ArticleLiterature Review

Diagnostic Performance of Stress Cardiac Magnetic Resonance Imaging in the Detection of Coronary Artery Disease

November 2007
Journal of the American College of Cardiology 50(14):1343-53

November 2007
50(14):1343-53

DOI:10.1016/j.jacc.2007.06.030

Source
PubMed

Authors:

Ben Dwamena

University of Michigan

Asim F Choudhri

The University of Tennessee Health Science Center

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The purpose of our study was to conduct an evidence-based evaluation of stress cardiac magnetic resonance imaging (MRI) in the diagnosis of coronary artery disease (CAD). Stress cardiac MRI has recently emerged as a noninvasive method in the detection of CAD, with 2 main techniques in use: 1) perfusion imaging; and 2) stress-induced wall motion abnormalities imaging. We examined studies from January 1990 to January 2007 using MEDLINE and EMBASE. A study was included if it: 1) used stress MRI as a diagnostic test for CAD (> or =50% diameter stenosis); and 2) used catheter X-ray angiography as the reference standard. Thirty-seven studies (2,191 patients) met the inclusion criteria, with 14 datasets (754 patients) using stress-induced wall motion abnormalities imaging and 24 datasets (1,516 patients) using perfusion imaging. Stress-induced wall motion abnormalities imaging demonstrated a sensitivity of 0.83 (95% confidence interval [CI] 0.79 to 0.88) and specificity of 0.86 (95% CI 0.81 to 0.91) on a patient level (disease prevalence = 70.5%). Perfusion imaging demonstrated a sensitivity of 0.91 (95% CI 0.88 to 0.94) and specificity of 0.81 (95% CI 0.77 to 0.85) on a patient level (disease prevalence = 57.4%). In studies with high disease prevalence, stress cardiac MRI, using either technique, demonstrates overall good sensitivity and specificity for the diagnosis of CAD. However, limited data are available regarding use of either technique in populations with low disease prevalence.

Fast-Strain Encoded Cardiac Magnetic Resonance During Vasodilator Perfusion Stress Testing

Article

Full-text available

Nov 2021

Background: Cardiac magnetic resonance perfusion imaging during vasodilator stress is an established modality in patients with suspected and known coronary artery disease (CAD). Aim: This study aimed to evaluate the performance of fast-Strain-Encoded-MRI (fast-SENC) for the diagnostic classification and risk stratification of patients with ischemic heart disease. Methods: Perfusion and fast-SENC cardiac magnetic resonance (CMR) images were retrospectively analyzed in 111 patients who underwent stress CMR. The average myocardial perfusion score index, global and segmental longitudinal and circumferential strain (GLS and GCS and SLS and SCS, respectively), were measured at rest and during stress. The combination of SLS and SCS was referred to as segmental aggregate strain (SAS). Segments exhibiting perfusion defects or SAS impairment during stress were defined as “ischemic.” All-cause mortality, non-fatal infarction, and urgent revascularization were deemed as our combined clinical endpoint. Results: During adenosine stress testing, 44 of 111 (39.6%) patients exhibited inducible perfusion abnormalities. During a mean follow-up of 1.94 ± 0.65 years, 25 (22.5%) patients reached the combined endpoint (death in n = 2, infarction in n = 3 and urgent revascularization in n = 20). Inducible perfusion defects were associated with higher number of segments with inducible SAS reduction ≥6.5% (χ² = 37.8, AUC = 0.79, 95% CI = 0.71–0.87, p < 0.001). In addition, patients with inducible perfusion defects or SAS impairment exhibited poorer outcomes (AUCPerf = 0.81 vs. AUCSAS = 0.74, p = NS vs. each other, and χ² = 30.8, HR = 10.3 and χ² = 9.5, HR = 3.5, respectively, p < 0.01 for both). Conclusion: Purely quantitative strain analysis by fast-SENC during vasodilator stress was related to the diagnosis of ischemia by first-pass perfusion and is non-inferior for the risk stratification of patients with ischemic heart disease. This may bear clinical implications, especially in patients with contraindications for contrast agent administration.

What Is the Clinical Impact of Stress CMR After the ISCHEMIA Trial?

Article

Full-text available

Jun 2021

After progressively receding for decades, cardiovascular mortality due to coronary artery disease has recently increased, and the associated healthcare costs are projected to double by 2030. While the 2019 European Society of Cardiology guidelines for chronic coronary syndromes recommend non-invasive cardiac imaging for patients with suspected coronary artery disease, the impact of non-invasive imaging strategies to guide initial coronary revascularization and improve long-term outcomes is still under debate. Recently, the ISCHEMIA trial has highlighted the fundamental role of optimized medical therapy and the lack of overall benefit of early invasive strategies at a median follow-up of 3.2 years. However, sub-group analyses excluding procedural infarctions with longer follow-ups of up to 5 years have suggested that patients undergoing revascularization had better outcomes than those receiving medical therapy alone. A recent sub-study of ISCHEMIA in patients with heart failure or reduced left ventricular ejection fraction (LVEF <45%) indicated that revascularization improved clinical outcomes compared to medical therapy alone. Furthermore, other large observational studies have suggested a favorable prognostic impact of coronary revascularization in patients with severe inducible ischemia assessed by stress cardiovascular magnetic resonance (CMR). Indeed, some data suggest that stress CMR-guided revascularization assessing the extent of the ischemia could be useful in identifying patients who would most benefit from invasive procedures such as myocardial revascularization. Interestingly, the MR-INFORM trial has recently shown that a first-line stress CMR-based non-invasive assessment was non-inferior in terms of outcomes, with a lower incidence of coronary revascularization compared to an initial invasive approach guided by fractional flow reserve in patients with stable angina. In the present review, we will discuss the current state-of-the-art data on the prognostic value of stress CMR assessment of myocardial ischemia in light of the ISCHEMIA trial results, highlighting meaningful sub-analyses, and still unanswered opportunities of this pivotal study. We will also review the available evidence for the potential clinical application of quantifying the extent of ischemia to stratify cardiovascular risk and to best guide invasive and non-invasive treatment strategies.

Routine Functional Testing or Standard Care in High-Risk Patients after Percutaneous Coronary Intervention

Article

Full-text available

May 2024
Curr Cardiol Rep

Purpose of Review This review aimed to collate the available evidence on outcomes following routine functional stress testing vs standard of care (i.e. symptom-guided stress testing) in high-risk patients following percutaneous coronary intervention (PCI). Recent Findings The most recent pragmatic POST-PCI trial provided randomized evidence showing that routine functional stress testing post-PCI did not lead to a reduction in 2-year ischemic cardiovascular events or all-cause mortality, as compared to a symptom-guided standard-of-care approach. This was also true for sub-analyses including multivessel or left main disease, diabetics, as well as following imaging or physiology guided PCI. Summary In the absence of a change in their clinical or functional status suggestive of stent failure, post-PCI routine periodic stress testing in stable patients on guideline-directed medical therapy is currently not recommended by American clinical practice guidelines. While evidence on the cost-effectiveness of routine stress testing strategy is scarce, physician, payer, and policy-level interventions to reduce inappropriate use of routine functional testing need to be addressed.

Simultaneous Viability Assessment and Invasive Coronary Angiography Using a Therapeutic CT System in Chronic Myocardial Infarction Patients

Article

May 2024

Safety, feasibility, and hemodynamic response of regadenoson for stress perfusion CMR

Article

Full-text available

Jun 2023

Owing to its pharmacodynamics and posology, the use of regadenoson for stress cardiac magnetic resonance (CMR) has potential advantages over other vasodilators. We sought to evaluate the safety, hemodynamic response and diagnostic performance of regadenoson stress-CMR in routine clinical practice. All regadenoson stress-CMR examinations performed between May 2017 and July 2020 at our institution were retrospectively reviewed. A total of 698 studies were included for the final analysis. A conventional stress/rest protocol was performed using a 1.5T MRI scanner (Magnetom Aera, Siemens Healthineers, Erlangen, Germany). Adverse events, clinical symptoms, and hemodynamic response were assessed. Diagnostic accuracy of the test was evaluated in patients who underwent invasive coronary angiography. Nearly half of patients (48.5%) remained asymptomatic. Most common clinical symptoms included dyspnea (137, 19.6%), chest pain (116, 16.6%) and flushing (44, 6.3%). Two patients (0.28%) could not complete the examination due to severe hypotension or unbearable chest pain. Overall, an increase in heart rate (HR) response (36.2% [IQR: 22.5?50.9]) and a decrease in systolic and diastolic blood pressure (BP) (median systolic BP response of -5% [IQR: -11.5-0.6]; median diastolic BP response of -6.3 mmHg [IQR: -13.4-0]) was observed. Patients with symptoms induced by regadenoson showed higher HR response (40.3%, IQR: 26.4?56.1 vs. 32.4%, IQR: 19-45.6, p < 0.001), whereas a blunted HR response was observed in diabetic (29.6%, IQR: 18.4?42 p < 0.001), obese (31.7%, IQR: 20.7?46.2 p = 0.005) and patients aged 70 years or older (32.9%, IQR: 22.6?43.1 p < 0.001). Overall, regadenoson stress-CMR showed 95.65% (IQ 91.49?99.81) sensitivity, 54.84% (IQ 35.71?73.97) specificity, 86.99% (IQ 82.74?94.68) positive predictive value, and 77.27% (IQ 57.49?97.06) negative predictive value for detecting significant coronary stenosis as compared with invasive coronary angiography. Regadenoson is a well-tolerated vasodilator that can be safely employed for stress perfusion CMR, with high diagnostic performance.

Safety and Efficacy of Regadenoson for Pediatric Stress Perfusion Cardiac MRI with Quantification of Myocardial Blood Flow

Article

Full-text available

Sep 2022

Myocardial stress perfusion magnetic resonance imaging is a non-invasive tool to assess for myocardial ischemia and viability. Pediatric myocardial stress perfusion MRI can be challenging due to multiple intravenous lines, sedation, inadequate breath holding, fast heart rates, and complex anatomy. We performed a retrospective analysis in 39 children to evaluate safety and efficacy of regadenoson, a coronary vasodilator administered via a single intravenous line (6–10 mcg/kg), with respiratory motion correction (MOCO) and semi-quantitative blood flow analysis. Stress response data and adverse events were recorded, and image quality compared between native and MOCO reconstructions, assessing for perfusion deficits. Semi-quantitative analysis compared myocardial perfusion reserve index (MPRI) between patients who had a focal perfusion defect, patients who had undergone an orthotopic heart transplant, and non-transplant patients with no focal defects. Stress perfusion was completed in 38/39 patients (median age 15 years with a 41 ± 27% rise in heart rate (p < 0.005). Fifteen out of thirty-eight had transient minor side effects with no major adverse events. MOCO image quality was better than non-MOCO (4.63 vs. 4.01 at rest, p < 0.005: 4.41 vs. 3.84 at stress, p < 0.005). Reversible perfusion defects were seen in 4/38 patients with lower segmental mean MPRI in the area of the perfusion defect, nearing statistical significance when compared to non-transplant patients with no defects (0.78 ± 0.22 vs. 0.99 ± 0.36, p = 0.07). The global MPRI of the 16 patients who had undergone orthotopic heart transplant was significantly lower than the non-transplant patients (0.75 ± 0.22 vs. 0.92 ± 0.23, p = 0.03). Regadenoson is a safe and effective coronary vasodilator for pediatric stress perfusion MRI with MOCO producing better image quality and allowing for semi-quantitative assessment of perfusion deficits that correlate with qualitative assessment.

C-CADZ: computational intelligence system for coronary artery disease detection using Z-Alizadeh Sani dataset

Article

Full-text available

Jun 2021
APPL INTELL

Coronary artery disease (CAD) is one of the most lethal diseases which is major cause of deaths around the globe. CAD is among such diseases with mortality rate approximately 7 million per annum. Though, early detection, prognostication and timely diagnosis can help in mortality rate reduction. Conventional CAD detection systems are cumbersome and expensive. Moreover, scarcity or uneven distribution of radiologists in different geographical locations is a hindrance in early diagnosis. Therefore, this is the time when researchers and doctors are collaboratively looking forward for developing a computational intelligence system in the area of medical imaging systems for prognostication, identification, treatment and disease diagnosis. To support the vision of researchers, a computational intelligence system for coronary artery disease diagnosis, C-CADZ, has been proposed. To validate the model, C-CADZ, the dataset namely, Z-Alizadeh Sani CAD dataset from UCI repository is considered. C-CADZ utilizes the fixed analysis of mixed data (FAMD) for feature extraction. FAMD extracts 96 features. In order to retrieve significant features, nature-inspired algorithms are utilized. C-CADZ implemented Synthetic Minority Oversampling Technique (SMOTE) to handle class-imbalanced data as machine learning (ML) predictive models are built to handle class-balanced datasets. Z-Score normalization technique is used for normalizing the dataset. Furthermore, C-CADZ is trained using ML classifiers, Random Forest (RF) and Extra Trees (ET) and validated using holdout validation scheme with hold-out ratio 3 : 1. Experimentation results show that C-CADZ outperforms state-of-the-art methods of last decades in terms of accuracy. C-CADZ has gained an increase in accuracy from state-of-the-art methods published in 2020 by 5.17% with performance metric 〈Acc, Sens, Spec〉≡〈97.37, 98.15, 95.45〉. The performance analysis shows that achieving highest accuracy and the stable nature of boxplot and ROC-AUC curve of RF-ET makes it suitable for heart disease prediction.

Role of Computed Tomography and Magnetic Resonance Imaging in the Diagnosis of Coronary Artery Disease: Indications and Applications

Article

Full-text available

Sep 2023

Coronary artery disease (CAD) is the leading cause of death worldwide. The diagnosis of CAD relies on the clinical history, electrocardiographic changes, and imaging findings. The available imaging methods include transthoracic echocardiography, computed tomography (CT), cardiac magnetic resonance (CMR) imaging, and invasive angiography. Over the last two decades, cardiac CT and CMR have emerged as promising noninvasive modalities in the assessment of patients with suspected and established CAD. Both the modalities have their own advantages and disadvantages which complement each other in comprehensive evaluation of CAD aiding in the diagnosis, guiding clinical decision-making, and improving risk stratification. In this article, we provide an overview of the techniques and clinical applications of cardiac CT and CMR imaging in the assessment of patients with CAD.

Bimetallic Metal–Organic Framework Nanoparticles for Monitoring Metabolic Changes in Cardiovascular Disorders

Article

Apr 2023

A group of disorders known as cardiovascular diseases (CVDs) affect the blood vessels that supply the heart muscle. CVDs are the leading global cause of death; however, the absence of a successful metabolomic strategy has impeded the advancement of CVD research. Because of this great challenge, bimetallic metal−organic framework (MOF) nanoparticles (NPs) have been developed for metabolic finger printings (MFs) in the study of molecular changes in CVD and coronary artery disease (CAD). A simple method for the design of various bimetallic MOF-NPs based on Zeolitic Imidazolate Frameworks (ZIFs) and bimetallic structure is reported. The serum MF was determined by examining 500 nL of natural serum in a few of seconds using the best bimetallic MOFs candidate (containing both Zn and Cu) integrated with assisted laser desorption/ionization mass spectrometry (LDI MS). Through the disclosed technology and a serum-based organization model, CVD patients could be differentiated from controls and CAD that have a sensitivity of 96% and a specificity of 93%. Furthermore, a portion of serum metabolic profiles with consistent changes can be used to track the progression of CVD, CAD, and controls. This study presents a state-of-the-art molecular approach for the metabolomic characterization of CVD and CAD that could one day be utilized to mimic clinical decisions in personalized therapy for cardiovascular disorders.

Preoperative Stress Testing before Non-Cardiac Surgery

Article

Full-text available

Mar 2023

The current guidelines from various medical societies provide a good summary of data regarding various preoperative exercise tests in patients prior to non-cardiac surgical interventions. However, there is no consensus among experts on the appropriateness of these methods for identifying risk groups for potential perioperative complications. A large volume of published studies describes the role of preoperative exercise stress testing impact in improving the prediction of potential cardiovascular (CV) risk in patients after non-cardiac surgery. Numerous stress tests are available in clinical practice, and the methods used and the best choice depends on the purpose of the study and the availability of equipment in the hospital. Traditionally, the value of exercise electrocardiography (ECG), or ECG stress test, has been based on the belief that it is beneficial for perioperative cardiac risk prediction. However, in the past two decades, the key role of this method has lost its importance due to the growing trend toward the use of imaging techniques. Moreover, in light of current trends, the six-minute walk test (6MWT) is a helpful tool in preoperative assessment and plays an important role in postoperative rehabilitation. Interestingly, the recent finding showed how 6MWT affects the risk of postoperative complications. Cardiopulmonary testing, as a dynamic clinical tool, determines the cardiorespiratory status of a patient. Various clinical indications for cardiopulmonary exercise testing include evaluation of therapy, stratification of risk factors, diagnosis of disease, and control of physical activity. Stress testing is one of the most practical ways of predicting perioperative risk and managing patients. This test is based on ischemia provoked by pharmacological agents or exercise. There is no established evidence of a significant advantage of pharmacological stress over exercise stress imaging in subjects who are capable enough to be physically active. All of these studies examined a stress test for induced myocardial ischemia. Currently, there are no data on the use of ischaemic stress tests, especially diastolic stress tests, in the assessment of perioperative risk before non-cardiac surgical interventions. We consider it promising and essential to continue research in this direction in patients with coronary heart disease and other categories of cardiac patients, in particular, comorbid and low-symptomatic individuals, before elective high-risk surgical interventions.

Myocardial perfusion in heart disease

Thesis

Nov 2022

Kristopher Knott

Heart disease: Coronary heart disease is a major cause of mortality and morbidity in the UK and globally. It is managed with medical therapy and coronary revascularisation to reduce symptoms and reduce risk of major adverse cardiovascular events. When patients present with chest pain, it is important to risk stratify those that would most benefit from invasive coronary assessment and those that can be managed with medical therapy alone. Myocardial perfusion techniques have been developed in order to do this. Cardiovascular magnetic resonance (CMR) with stress perfusion: CMR allows the non-invasive assessment of coronary artery disease (CAD). Under conditions of vasodilator stress, a gadolinium based contrast agent is injected and during the first pass through the left ventricle, perfusion defects can be observed. There is a strong evidence base for perfusion CMR but the technique is qualitative, relies on experienced operators and potentially misses globally low perfusion such as in cases of “balanced” ischaemia. Quantitative perfusion CMR: In contrast, quantitative perfusion techniques allow the calculation of myocardial blood flow (MBF). It is more objective, less reliant on the expert observer and can give additional insights into microvascular disease and cardiomyopathy. As well as being less subjective, quantitative perfusion has other advantages for example it allows full assessment of ischaemic burden and may contain prognostic information that could be used to risk stratify and improve patient care. However, quantitative perfusion has been outside the realm of routine clinical practice due to difficulties in acquiring suitable data for full quantification and the laborious nature of analysing it. Perfusion mapping: Peter Kellman, Hui Xue and colleagues at the National Institutes for Health, USA developed the “perfusion mapping” technique to address these limitations. Perfusion maps are generated automatically and inline during the CMR scan and each voxel encodes myocardial blood flow. This allows the instant quantification of MBF without complex acquisition techniques and post processing. In this thesis I have taken perfusion mapping and deployed in the real-world at a scale an order of magnitude higher than prior quantitative perfusion studies, developing the evidence base for routine clinical use across a broad range of diseases and scenarios: In coronary artery disease: I have shown that perfusion mapping is accurate to detect coronary artery stenosis as defined by 3D quantitative coronary angiography in a single centre, 50 patient study. Transmural and subendocardial perfusion are particularly sensitive to detect coronary stenoses with performances similar to expert readers. There is a high sensitivity and high negative predictive value making perfusion mapping a good “rule-out” test for coronary disease. Quantitative perfusion and prognosis: I investigated whether stress MBF and myocardial perfusion reserve (MPR) calculated by perfusion mapping would encode prognostic information in a 1049 patient multi-centre study over a mean follow up time of 605 days. Both stress MBF and MPR were independently associated with death and major adverse cardiovascular events (MACE). The hazard ratio for MACE was 2.14 for each 1ml/g/min decrease in stress MBF and 1.74 for each unit decrease in MPR. This work can now be taken forward with prospective studies in order to better risk stratify patients, including those without perfusion defects on clinical read. Reference ranges and non-obstructive coronary disease: I sought to determine the factors that contribute to perfusion in a multi-centre registry study. In patients with no obstructive coronary artery disease, stress MBF was reduced with age, diabetes, left ventricular hypertrophy (LVH) and the use of beta blockers. Rest MBF was influenced by sex (higher in females) and reduced with beta blockers. This study suggests patient factors beyond coronary artery disease (and therefore likely microvascular disease) should also be considered when interpreting quantitative perfusion studies. In cardiomyopathy: I also investigated myocardial perfusion in cardiomyopathy looking at Fabry disease as an example disease. In a prospective, observational, single centre study of 44 patients and 27 controls I found Fabry patients had reduced perfusion (and therefore likely microvascular dysfunction), particularly in the subendocardium and was associated with left ventricular hypertrophy (LVH), glycophospholipid storage and scar. Perfusion was reduced even in patients without LVH suggesting it is an early disease marker. In conclusion, in this thesis, I have developed an evidence base for quantitative perfusion CMR and demonstrated how it can be integrated into routine clinical care. Perfusion mapping is accurate for detecting coronary artery stenosis and encodes prognostic information. Further work in this area could enable patients to be risk stratified based on their myocardial perfusion in order to reduce the morbidity and mortality associated with epicardial and microvascular coronary artery disease. Following on from this work, two further British Heart Foundation Clinical Research Training Fellowships have been awarded to further investigate quantitative perfusion in patients following surgical revascularisation of coronary disease and in patients with hypertrophic cardiomyopathy.

Using neural network and support vector machine learning methods for classification of multi-lead ECG signals

Article

Full-text available

Jan 2023

Introduction ECG data play an important role in the diagnostics of various cardiovascular diseases. Classification of multi-lead ECG signals could be challenging even for well-trained physicians. In this study we propose a new approach for multi-lead ECG classification. Method Five-types of 15-lead ECG data namely healthy control, bundle branch block, cardiomyopathy, Dysrhythmia, and myocardial infarction patients from two types of datasets, 5319 and 6647 heartbeats from Baqiyatallah and PTB Diagnostic ECG database, were used, respectively. One-dimensional total variation regularization was used to denoising ECG data. Heartbeats were extracted by one cardiologist and saved as images with jpg format. Histogram of oriented gradients method was used to extract feature of images. for classification task support vector machine and fully connected neural network were used. Five-fold cross validation was used for validating the models. Result For 15-lead ECG PTB Diagnostic database, the best classification models are SVM model with cubic (accuracy: 99.9%, Range: 99.77% - 100%) and quadratic (accuracy: 99.88%, Range: 99.77%-100%) kernel function, for this dataset fully connected accuracy is 99.4% with range of 99.02%- 99.70%. Regarding to the Baqyatallah dataset SVM with cubic (accuracy: 99.83%, Range:99.72%-100%) and quadratic (accuracy: 99.77%, Range: 99.62%-99.9%) were the best classification model and the accuracy for fully connected neural network was 99.1% with the range of 98.59%-99.62% based on HOG descriptors. Expected sigmodal kernel all classification method have accuracy more than 99%. Discussion simultaneous use of HOG feature extraction method and appropriate classification algorithm such as SVM or fully connected neural network can classify 15-lead ECG heart-beat for different heart disease with high accuracy and adding other relevant patients’ information can be easily done in order to increase the method performance.

LRSE-Net: Lightweight Residual Squeeze-and-Excitation Network for Stenosis Detection in X-ray Coronary Angiography

Article

Full-text available

Nov 2022

Coronary heart disease is the primary cause of death worldwide. Among these, ischemic heart disease and stroke are the most common diseases induced by coronary stenosis. This study presents a Lightweight Residual Squeeze-and-Excitation Network (LRSE-Net) for stenosis classification in X-ray Coronary Angiography images. The proposed model employs redundant kernel deletion and tensor decomposition by Depthwise Separable Convolutions to reduce the model parameters up to 48.6 x concerning a Vanilla Residual Squeeze-and-Excitation Network. Furthermore, the reduction ratios of each Squeeze-and-Excitation module are optimized individually to improve the feature recalibration. Experimental results for Stenosis Detection on the publicly available Deep Stenosis Detection Dataset and Angiographic Dataset demonstrate that the proposed LRSE-Net achieves the best Accuracy—0.9549/0.9543, Sensitivity—0.6320/0.8792, Precision—0.5991/0.8944, and F1-score—0.6103/0.8944, as well as competitive Specificity of 0.9620/0.9733.

Diagnostic radiology methods for assessing coronary artery bypass graft viability

Article

Full-text available

Oct 2022

The review describes available modern radiological methods which are currently applied for a detailed and comprehensive anatomical and functional assessment of the viability of various coronary artery bypass grafts. In addition, it presents some aspects of the implementation of these methods and clinical interpretation of the results.

Safety of Stress Cardiovascular Magnetic Resonance in Patients With Moderate to Severe Aortic Valve Stenosis

Article

Full-text available

Sep 2022

Background: Dobutamine and adenosine stress cardiac magnetic resonance (CMR) imaging is relatively contraindicated in patients with moderate to severe aortic valve stenosis (AS). We aimed to determine the safety of dobutamine and adenosine stress CMR in patients with moderate to severe AS. Methods: In this retrospective study patients with AS who underwent either dobutamine or adenosine stress CMR for exclusion of obstructive coronary artery disease were enrolled. We recorded clinical data, CMR and echocardiography findings, and complications as well as minor symptoms. Patients with AS were compared to matched individuals without AS. Results: A total of 187 patients with AS were identified and compared to age-, gender- and body mass index-matched 187 patients without AS. No severe complications were reported in the study nor the control group. The reported frequency of non-severe complications and minor symptoms were similar between the study and the control groups. Nineteen patients with AS experienced non-severe complications or minor symptoms during dobutamine stress CMR compared to eighteen patients without AS (p = 0.855). One patient with AS and two patients without AS undergoing adenosine stress CMR experienced minor symptoms (p = 0.562). Four examinations were aborted because of chest pain, paroxysmal atrial fibrillation and third-degree atrioventricular block. Inducible ischaemia, prior coronary artery bypass grafting, prior stroke and age were associated with a higher incidence of complications and minor symptoms. Conclusions: Moderate to severe AS was not associated with complications during CMR stress test. The incidence of non-severe complications and minor symptoms was greater with dobutamine.

Dobutamine Stress Cardiac MRI in Pediatric Patients with Suspected Coronary Artery Disease

Article

Full-text available

Sep 2022
PEDIATR CARDIOL

Following current practice, pediatric patients with treated congenital coronary malformations or acquired coronary disease undergo Cardio-Pulmonary Exercise Test (CPET), stress Echocardiography and Electrocardiography (sEcho, sEKG), and Coronary Angiography (CA). Stress cMRI can assess cardiac function, myocardial viability, and stress/rest perfusion deficit—without radiation exposure, general anesthesia, and hospitalization—in a single non-invasive exam. The aim of our pilot study is to assess the feasibility and diagnostic accuracy of Dobutamine stress cMRI compared to the current procedures (sEcho, CPET, CA). The prospective study is focused on pediatric patients, at risk for or with previously diagnosed coronary artery disease: d-looped TGA after arterial Switch, Kawasaki disease, and anomalous origin of left coronary artery from pulmonary artery (ALCAPA) after coronary artery reimplantation. We have compared the results of MRI coronary angiography, and Dobutamine stress cMRI with traditional tests. All these diagnostic exams were acquired in a timeframe of 3 month, in a blinded fashion. All the 13 patients (age: 12 ± 2 years, median 12,7 y) recruited, completed the study without major adverse events. The mean heart rate-pressure product was 25,120 ± 5110 bpm x mm Hg. The target heart rate of 85% of the maximal theoretical was reached by 10 (77%) patients. The comparison between cardiac MRI coronarography versus the gold standard Coronary Angiography to identify the patency of the origin and the proximal pathway of the coronary arteries shows a sensitivity of 100% (confidence interval: 2,5–100%), specificity 92% (confidence interval: 64–100%). The stress test was well tolerated for the 77% of the patients and completed by the totality of patients (Table 3). Three patients (23%) had mild symptoms: nausea, vomiting, or general discomfort. In pediatric patients with a potential or definite diagnosis of coronary artery disease, stress cMRI combines an effective assessment of proximal coronary arteries anatomy with cardiac function, myocardial perfusion, and viability in a single examination. Stress cMRI can be proposed as alternative, standalone test.

2022 ESC Guidelines on cardiovascular assessment and management of patients undergoing non-cardiac surgery

Article

Full-text available

Aug 2022

Improving Convolutional Neural Network Learning based on a Hierarchical Bezier Generative Model for Stenosis Detection in X-ray images

Article

Mar 2022
COMPUT METH PROG BIO

Background and Objective: Automatic detection of stenosis on X-ray Coronary Angiography (XCA) images may help diagnose early coronary artery disease. Stenosis is manifested by a buildup of plaque in the arteries, decreasing the blood flow to the heart, increasing the risk of a heart attack. Convolutional Neural Networks (CNNs) have been successfully applied to identify pathological, regular, and featured tissues on rich and diverse medical image datasets. Nevertheless, CNNs find operative and performing limitations while working with small and poorly diversified databases. Transfer learning from large natural image datasets (such as ImageNet) has become a de-facto method to improve neural networks performance in the medical image domain. Methods: This paper proposes a novel Hierarchical Bezier-based Generative Model (HBGM) to improve the CNNs training process to detect stenosis. Herein, artificial image patches are generated to enlarge the original database, speeding up network convergence. The artificial dataset consists of 10,000 images containing 50% stenosis and 50% non-stenosis cases. Besides, a reliable Fréchet Inception Distance (FID) is used to evaluate the generated data quantitatively. Therefore, by using the proposed framework, the network is pre-trained with the artificial datasets and subsequently fine-tuned using the real XCA training dataset. The real dataset consists of 250 XCA image patches, selecting 125 images for stenosis and the remainder for non-stenosis cases. Furthermore, a Convolutional Block Attention Module (CBAM) was included in the network architecture as a self-attention mechanism to improve the efficiency of the network. Results: The results showed that the pre-trained networks using the proposed generative model outperformed the results concerning training from scratch. Particularly, an accuracy, precision, sensitivity, and F1-score of 0.8934, 0.9031, 0.8746, 0.8880, 0.9111, respectively, were achieved. The generated artificial dataset obtains a mean FID of 84.0886, with more realistic visual XCA images. Conclusions: Different ResNet architectures for stenosis detection have been evaluated, including attention modules into the network. Numerical results demonstrated that by using the HBGM is obtained a higher performance than training from scratch, even outperforming the ImageNet pre-trained models.

Comparative Analysis of Myocardial Viability Multimodality Imaging in Patients with Previous Myocardial Infarction and Symptomatic Heart Failure

Article

Full-text available

Mar 2022

Background and Objectives: To compare the accuracy of multimodality imaging (myocardial perfusion imaging with single-photon emission computed tomography (SPECT MPI), 18F-fluorodeoxyglucose positron emission tomography (18F-FDG PET), and cardiovascular magnetic resonance (CMR) in the evaluation of left ventricle (LV) myocardial viability for the patients with the myocardial infarction (MI) and symptomatic heart failure (HF). Materials and Methods: 31 consecutive patients were included in the study prospectively, with a history of previous myocardial infarction, symptomatic HF (NYHA) functional class II or above, reduced ejection fraction (EF) ≤ 40%. All patients had confirmed atherosclerotic coronary artery disease (CAD), but conflicting opinions regarding the need for percutaneous intervention due to the suspected myocardial scar tissue. All patients underwent transthoracic echocardiography (TTE), SPECT MPI, 18F-FDG PET, and CMR with late gadolinium enhancement (LGE) examinations. Quantification of myocardial viability was assessed in a 17-segment model. All segments that were described as non-viable (score 4) by CMR LGE and PET were compared. The difference of score between CMR and PET we named reversibility score. According to this reversibility score, patients were divided into two groups: Group 1, reversibility score > 10 (viable myocardium with a chance of functional recovery after revascularization); Group 2, reversibility score ≤ 10 (less viable myocardium when revascularisation remains questionable). . Results: 527 segments were compared in total. A significant difference in scores 1, 2, 3 group, and score 4 group was revealed between different modalities. CMR identified “non-viable” myocardium in 28.1% of segments across all groups, significantly different than SPECT in 11.8% PET in 6.5% Group 1 (viable myocardium group) patients had significantly higher physical tolerance (6 MWT (m) 3892 ± 94.5 vs. 301.4 ± 48.2), less dilated LV (LVEDD (mm) (TTE) 53.2 ± 7.9 vs. 63.4 ± 8.9; MM (g) (TTE) 239.5 ± 85.9 vs. 276.3 ± 62.7; LVEDD (mm) (CMR) 61.7 ± 8.1 vs. 69.0 ± 6.1; LVEDDi (mm/m2) (CMR) 29.8 ± 3.7 vs. 35.2 ± 3.1), significantly better parameters of the right heart (RV diameter (mm) (TTE) 33.4 ± 6.9 vs. 38.5 ± 5.0; TAPSE (mm) (TTE) 18.7 ± 2.0 vs. 15.2 ± 2.0), better LV SENC function (LV GLS (CMR) −14.3 ± 2.1 vs. 11.4 ± 2.9; LV GCS (CMR) −17.2 ± 4.6 vs. 12.7 ± 2.6), smaller size of involved myocardium (infarct size (%) (CMR) 24.5 ± 9.6 vs. 34.8 ± 11.1). Good correlations were found with several variables (LVEDD (CMR), LV EF (CMR), LV GCS (CMR)) with a coefficient of determination (R2) of 0.72. According to the cut-off values (LVEDV (CMR) > 330 mL, infarct size (CMR) > 26%, and LV GCS (CMR) < −15.8), we performed prediction of non-viable myocardium (reversibility score < 10) with the overall percentage of 80.6 (Nagelkerke R2 0.57). Conclusions: LGE CMR reveals a significantly higher number of scars, and the FDG PET appears to be more optimistic in the functional recovery prediction. Moreover, using exact imaging parameters (LVEDV (CMR) > 330 mL, infarct size (CMR) > 26% and LV GCS (CMR) < −15.8) may increase sensitivity and specificity of LGE CMR for evaluation of non-viable myocardium and lead to a better clinical solution (revascularization vs. medical treatment) even when viability is low in LGE CMR, and FDG PET is not performed.

Long‐term prognostic value of vasodilator stress cardiac magnetic resonance in patients with atrial fibrillation

Article

Full-text available

Dec 2021

Aims: Although the prevalence of coronary artery disease (CAD) is high among patients with atrial fibrillation (AF), studies on stress perfusion cardiac magnetic resonance (CMR) imaging frequently exclude patients with AF, and its prognostic and diagnostic value in high-risk patients with suspected or known CAD remains unclear. Methods and results: In this longitudinal cohort study, we included 164 consecutive patients with AF during vasodilator perfusion CMR. Diagnostic value was evaluated regarding invasive coronary angiography in a subset of patients. We targeted a follow-up of >5 years and used CMR results as stratification, and the primary outcome was major adverse cardiac events [MACE, cardiovascular (CV) death and myocardial infarction (MI)]. Secondary outcomes included late coronary revascularization or stroke and the components of the primary outcome. Of the whole cohort (73.8% male, mean age 72.2 years ± 7.8 SD), 99.4% were successfully scanned (163/164 patients). Median CHA2DS2-VASc score was 4 [interquartile range (IQR) 3-5], and median 10-year risk for CV events based on SMART risk score was high (24%, IQR 16-32%). Thirty-two patients (19.6%) presented with ischaemia and 52 patients (31.9%) with late gadolinium enhancement (LGE). A combination of LGE and inducible ischaemia was present in 20 patients (12.3%). Diagnostic accuracy was 86.2% [confidence interval (CI) 68.3-96.1%]. The median follow-up was 6.6 years (IQR 3.6-7.8). Ischaemia in vasodilator perfusion CMR was significantly associated with the occurrence of MACE [P < 0.01; hazard ratio (HR) 2.65, CI 1.39-5.08], as well as LGE (P = 0.03; 1.74, CI 1.07-3.64) and the combination of both (P < 0.01; HR 2.67, CI 1.59-5.62). After adjustment by age, left ventricular ejection fraction, and the presence of diabetes, ischaemia in vasodilator perfusion CMR remained significantly associated with the occurrence of MACE (2.10, CI 1.08-4.10; P = 0.03). In secondary endpoint analysis, there was a significant association of ischaemia in CMR with CV death (P < 0.05; HR 1.93, CI 0.95-3.9) and MI (P < 0.01; HR 13, CI 1.35-125.4), while no significant association was found regarding the occurrence of revascularization (P = 0.45; HR 1.43, CI 0.57-3.58) or stroke (P = 0.99; HR 0.99, CI 0.21-2.59). Conclusions: Vasodilator stress perfusion CMR demonstrated an excellent diagnostic and significant prognostic value at long-term follow-up in high-risk patients with persistent AF and suspected or known CAD.

Myocardial Viability, Functional Status, and Collaterals of Patients With Chronically Occluded Coronary Arteries

Article

Full-text available

Nov 2021

Objective: Viability and functional assessments are recommended for indication and intervention for chronic coronary total occlusion (CTO). We aimed to evaluate myocardial viability and left ventricular (LV) functional status by using cardiovascular magnetic resonance (CMR) and to investigate the relationship between them and collaterals in patients with CTO. Materials and Methods: We enrolled 194 patients with one CTO artery as detected by coronary angiography. Patients were scheduled for CMR within 1 week after coronary angiography. Results: A total of 128 CTO territories (66%) showed scar based on late gadolinium enhancement (LGE) imaging. There were 1,112 segments in CTO territory, while only 198 segments (18%) subtended by the CTO artery showed transmural scar (i.e., >50% extent on LGE). Patients with viable myocardium had higher LV ejection fraction (LVEF) (56.7 ± 13.5% vs. 48.3 ± 15.4%, p < 0.001) than those with transmural scar. Angiographically, well-developed collaterals were found in 164 patients (85%). There was no significant correlation between collaterals and the presence of myocardial scar ( p = 0.680) or between collaterals and LVEF ( p = 0.191). Nevertheless, more segments with transmural scar were observed in patients with poorly-developed collaterals than in those with well-developed collaterals (25 vs. 17%, p = 0.010). Conclusion: Myocardial infarction detected by CMR is widespread among patients with CMO, yet only a bit of transmural myocardial scar was observed within CTO territory. Limited number of segments with transmural scar is associated with preserved LV function. Well-developed collaterals are not related to the prevalence of myocardial scar or systolic functioning, but could be related to reduce number of non-viable segments subtended by the CTO artery.

Stress testing and noninvasive coronary imaging: What’s the best test for my patient?

Article

Full-text available

Sep 2021

Coronary artery disease (CAD) causes significant morbidity and mortality. Accurate noninvasive evaluation is important to facilitate appropriate diagnosis and treatment. The ubiquitous nature of CAD requires all practitioners, regardless of their specialty, to be familiar with noninvasive diagnostic modalities. This article reviews currently available tests, including specific features, diagnostic and prognostic value, strengths, and limitations.

Clinical Translation of Three-Dimensional Scar, Diffusion Tensor Imaging, Four-Dimensional Flow, and Quantitative Perfusion in Cardiac MRI: A Comprehensive Review

Article

Full-text available

Jul 2021

Cardiovascular magnetic resonance (CMR) imaging is a versatile tool that has established itself as the reference method for functional assessment and tissue characterisation. CMR helps to diagnose, monitor disease course and sub-phenotype disease states. Several emerging CMR methods have the potential to offer a personalised medicine approach to treatment. CMR tissue characterisation is used to assess myocardial oedema, inflammation or thrombus in various disease conditions. CMR derived scar maps have the potential to inform ablation therapy—both in atrial and ventricular arrhythmias. Quantitative CMR is pushing boundaries with motion corrections in tissue characterisation and first-pass perfusion. Advanced tissue characterisation by imaging the myocardial fibre orientation using diffusion tensor imaging (DTI), has also demonstrated novel insights in patients with cardiomyopathies. Enhanced flow assessment using four-dimensional flow (4D flow) CMR, where time is the fourth dimension, allows quantification of transvalvular flow to a high degree of accuracy for all four-valves within the same cardiac cycle. This review discusses these emerging methods and others in detail and gives the reader a foresight of how CMR will evolve into a powerful clinical tool in offering a precision medicine approach to treatment, diagnosis, and detection of disease.

Transfer Learning in Segmenting Myocardium Perfusion Images

Chapter

Mar 2024

Cardiac magnetic resonance perfusion (CMRP) images are used to assess the local function and permeability of the heart muscle. The perfusion analysis requires the segmentation of cardiac inner and outer walls of the left ventricle (LV). However, the available perfusion datasets are limited or have no annotations. A fair dataset was annotated to employ the latest and most effective Deep Learning (DL) methodologies. In this paper, we employ similar cardiac imaging protocols in terms of cardiac geometry by initially training using CINE images and performing domain adaptation to CMRP images using Unet architectures with different backbones (VGG16, ResNet50, and ResNet152). We also experimented transfer learning (TL) with ImageNet weights by using these architectures separately. Surprisingly, the results were considerable; using CINE images’ weights with ResNet50 as a backbone encoder had better results than other models. This experiment's validation results of dice coefficient, recall, precision, and dice loss results are 0.85, 0.776, 0.94, and 0.148, respectively. The complexity of the data was investigated by finding the intra-observer error using the dice coefficient; the mean result of the intra-observer was 0.796. This study showed how valuable finding TL may help in studying the CMRP images and if the insufficiency of data could be overcome to develop more models to assist in diagnosing heart diseases.

Artificial intelligence in cardiovascular imaging: advances and challenges

Chapter

Jan 2024

Cardiac Imaging in Women with Suspected Ischemic Heart Disease

Chapter

Nov 2023

Cardiovascular imaging has undergone advances over the past decades and is increasingly used for the diagnosis of atherosclerotic disease in men and women. Recent guidelines suggest the use of stress imaging in symptomatic women at intermediate or high pretest probability of having ischemic heart disease, as well as the use of coronary computed tomography angiography to delineate the presence and location of coronary plaque. There are differences in pathophysiology of atherosclerotic disease in women, as women are more likely to have nonobstructive disease, often caused by abnormal coronary reactivity, microvascular dysfunction, as well as plaque erosion and distal microembolization. Myocardial perfusion imaging with positron emission tomography (PET) or magnetic resonance imaging (MRI) can aid in the diagnosis of microvascular dysfunction, making it even more valuable in women for an earlier and more accurate diagnosis leading to improved management and outcomes in women.

Chest Pain Evaluation – Diagnostic Testing

Article

Full-text available

Sep 2023

Chest pain/discomfort (CP) is a common symptom and can be a diagnostic dilemma for many clinicians. The misdiagnosis of an acute or progressive chronic cardiac etiology may carry a significant risk of morbidity and mortality. This review summarizes the different options and modalities for establishing the diagnosis and severity of coronary artery disease. An effective test selection algorithm should be individually tailored to each patient to maximize diagnostic accuracy in a timely fashion, determine short- and long-term prognosis, and permit implementation of evidence-based treatments in a cost-effective manner. Through collaboration, a decision algorithm was developed (www.chowmd.ca/cadtesting) that could be adopted widely into clinical practice.

The Prognostic Value of Qualitative and Quantitative Stress CMR in Patients with Known or Suspected CAD

Article

Aug 2023

Background: Recent studies suggest that quantitative cardiac magnetic resonance (CMR) may have more accuracy than qualitative CMR in coronary artery disease (CAD) diagnosis. However, the prognostic value of quantitative and qualitative CMR has not been compared systematically. Objectives: The objective was to conduct a systematic review and meta-analysis assessing the utility of qualitative and quantitative stress CMR in the prognosis of patients with known or suspected CAD. Methods: A comprehensive search was performed through Embase, Scopus, Web of Science, and Medline. Studies that used qualitative vasodilator CMR or quantitative CMR assessments to compare the prognosis of patients with positive and negative CMR results were extracted. A meta-analysis was then performed to assess: 1) major adverse cardiovascular events (MACE) including cardiac death, nonfatal myocardial infarction (MI), unstable angina, and coronary revascularization; and 2) cardiac hard events defined as the composite of cardiac death and nonfatal MI. Results: Forty-one studies with 38,030 patients were included in this systematic review. MACE occurred significantly more in patients with positive qualitative (HR: 3.86; 95% CI: 3.28-4.54) and quantitative (HR: 4.60; 95% CI: 1.60-13.21) CMR assessments. There was no significant difference between qualitative and quantitative CMR assessments in predicting MACE (P = 0.75). In studies with qualitative CMR assessment, cardiac hard events (OR: 7.21; 95% CI: 4.99-10.41), cardiac death (OR: 5.63; 95% CI: 2.46-12.92), nonfatal MI (OR: 7.46; 95% CI: 3.49-15.96), coronary revascularization (OR: 6.34; 95% CI: 3.42-1.75), and all-cause mortality (HR: 1.66; 95% CI: 1.12-2.47) were higher in patients with positive CMR. Conclusions: The presence of myocardial ischemia on CMR is associated with worse clinical outcomes in patients with known or suspected CAD. Both qualitative and quantitative stress CMR assessments are helpful tools for predicting clinical outcomes.

Kardio-MRT in der Sportkardiologie

Chapter

Jun 2023

Diagnosis and Treatment of Cardiovascular Disease in Women

Article

Aug 2018

The Role and Advantages of Cardiac Magnetic Resonance in the Diagnosis of Myocardial Ischemia

Article

Feb 2023

Ischemic heart disease continues to be the leading cause of death and disability worldwide. For the diagnosis of ischemic heart disease, some form of cardiac stress test involving exercise or pharmacological stimulation continues to play an important role, despite advances within modalities like computer tomography for the noninvasive detection and characterization of epicardial coronary lesions. Among noninvasive stress imaging tests, cardiac magnetic resonance (CMR) combines several capabilities that are highly relevant for the diagnosis of ischemic heart disease: assessment of wall motion abnormalities, myocardial perfusion imaging, and depiction of replacement and interstitial fibrosis markers by late gadolinium enhancement techniques and T1 mapping. On top of these qualities, CMR is also well tolerated and safe in most clinical scenarios, including in the presence of cardiovascular implantable devices, while in the presence of renal disease, gadolinium-based contrast should only be used according to guidelines. CMR also offers outstanding viability assessment and prognostication of cardiovascular events. The last 2019 European Society of Cardiology guidelines for chronic coronary syndromes has positioned stress CMR as a class I noninvasive imaging technique for the diagnosis of coronary artery disease in symptomatic patients. In the present review, we present the current state-of-the-art assessment of myocardial ischemia by stress perfusion CMR, highlighting its advantages and current shortcomings. We discuss the safety, clinical, and cost-effectiveness aspects of gadolinium-based CMR-perfusion imaging for ischemic heart disease assessment.

Chronic Coronary Artery Disease

Chapter

Mar 2023

This chapter presents multiple‐choice question‐and‐answers on the topic of chronic coronary artery disease. It is written for the primary purpose of helping candidates prepare for the American Board of Internal Medicine subspecialty certification. It will be very useful for those preparing for initial and recertification exams in Cardiology. Each of the 44 questions is followed by four answers to choose from and the discussions address not only the rationale behind picking the right choice, but also fills in information around the topic so that important key concepts are clearly laid out. The answers are explained in detail, accompanied by references to major trials and some clinical pearls. The chapter also facilitates comprehensive and critical review of cardiovascular medicine to enhance one's diagnostic and therapeutic skills.

A Comprehensive Review: Epidemiological Strategies, Catheterization and Biomarkers used as a Bioweapon in Diagnosis and Management of Cardio Vascular Diseases

Article

Feb 2023
CURR PROB CARDIOLOGY

Coronary artery disease (CAD) is a serious health problem that causes a considerable number of mortality in a number of affluent nations throughout the world. The estimated death encountered in many developed countries includes including Pakistan, reached 111,367 and accounted for 9.87% of all deaths, despite the mortality rate being around 7.2 million deaths per year, or 12% of all estimated deaths accounted annually around the globe, with improved health systems. Atherosclerosis progressing causes the coronary arteries to become partially or completely blocked, which results in CAD. Additionally, smoking, diabetes mellitus, homocystinuria, hypertension, obesity, hyperlipidemia, and psychological stress are risk factors for CAD. The symptoms of CAD include angina which is described as a burning, pain or discomfort in the chest, nausea, weakness, shortness of breath, lightheadedness, and pain or discomfort in the arms or shoulders. Atherosclerosis and thrombosis are the two pathophysiological pathways most frequently involved in acute coronary syndrome (ACS). Asymptomatic plaque disruption, plaque bleeding, symptomatic coronary blockage, and myocardial infarction are the prognoses for CAD. In this review, we will focus on medicated therapy which is being employed for the relief of angina linked with CAD including antiplatelet medicines, nitrates, calcium antagonists, blockers, catheterization, and the frequency of recanalized infarct-related arteries in patients with acute anterior wall myocardial infarction (AWMI). Furthermore, we have also enlightened the importance of biomarkers that are helpful in the diagnosis and management of CAD.

An automatic segmentation method with self-attention mechanism on left ventricle in gated PET/CT myocardial perfusion imaging

Article

Nov 2022
COMPUT METH PROG BIO

Objectives We aimed to propose an automatic segmentation method for left ventricular (LV) from 16 electrocardiogram (ECG) -gated ¹³N-NH3 PET/CT myocardial perfusion imaging (MPI) to improve the performance of LV function assessment. Methods Ninety-six cases with confirmed or suspected obstructive coronary artery disease (CAD) were enrolled in this research. The LV myocardial contours were delineated by physicians as ground truth. We developed an automatic segmentation method, which introduces the self-attention mechanism into 3D U-Net to capture global information of images so as to achieve fine segmentation of LV. Three cross-validation tests were performed on each gate (64 vs. 32 for training vs. validation). The effectiveness was validated by quantitative metrics (modified hausdorff distance, MHD; dice ratio, DR; 3D MHD) as well as cardiac functional parameters (end-systolic volume, ESV; end-diastolic volume, EDV; ejection fraction, EF). Furthermore, the feasibility of the proposed method was also evaluated by intra- and inter-observers with DR and 3D-MHD. Results Compared with backbone network, the proposed approach improved the average DR from 0.905 ± 0.0193 to 0.9202 ± 0.0164, and decreased the average 3D MHD from 0.4611 ± 0.0349 to 0.4304 ± 0.0339. The average relative error of LV volume between proposed method and ground truth is 1.09±3.66%, and the correlation coefficient is 0.992±0.007 (P< 0.001). The EDV, ESV, EF deduced from the proposed approach were highly correlated with ground truth (r ≥ 0.864, P< 0.001), and the correlation with commercial software is fair (r ≥ 0.871, P < 0.001). DR and 3D MHD of contours and myocardium from two observers are higher than 0.899 and less than 0.5194. Conclusion The proposed approach is highly feasible for automatic segmentation of the LV cavity and myocardium, with potential to benefit the precision of LV function assessment.

USING NON-INVASIVE METHODS FOR EVALUATING MYOCARDIAL ISCHEMIA IN ASSESSMENT OF THE FUNCTIONAL SIGNIFICANCE OF INTERMEDIATE CORONARY ARTERY STENOSES IN PATIENTS WITH CHRONIC ISCHEMIC HEART DISEASE

Article

Sep 2016

Key points of using non-invasive methods for evaluating myocardial ischemia (exercise electrocardiogram, stress echocardiography, single photon emission computed tomography and myocardial perfusion imaging with stress-test) in clinical practice to determine the functional significance of intermediate coronary artery stenoses (50-70% of the vascular lumen) are discussed in the review.

Clustering of patients with inconclusive non-invasive stress testing referred for vasodilator stress cardiovascular magnetic resonance

Article

Oct 2022
ARCH CARDIOVASC DIS

Background. – Inconclusive non-invasive stress testing is associated with impaired outcome. This population is very heterogeneous, and its characteristics are not well depicted by conventional methods. Aims. – To identify patient subgroups by phenotypic unsupervised clustering, integrating clinical and cardiovascular magnetic resonance data to unveil pathophysiological differences between subgroups of patients with inconclusive stress tests. Methods. – Between 2008 and 2020, consecutive patients with a first inconclusive non-invasive stress test referred for stress cardiovascular magnetic resonance were followed for the occurrence of major adverse cardiovascular events (defined as cardiovascular death or myocardial infarction). A cluster analysis was performed on clinical and cardiovascular magnetic resonance variables. Results. – Of 1402 patients (67% male; mean age 70 ± 11 years) who completed the follow-up (median 6.5 years, interquartile range 5.6–7.5 years), 197 experienced major adverse cardiovascular events (14.1%). Three distinct phenogroups were identified based upon unsupervised hierarchical clustering of principal components: phenogroup 1 = history of percutaneous coronary intervention with viable myocardial scar and preserved left ventricular ejection fraction; phenogroup 2 = atrial fibrillation with preserved left ventricular ejection fraction; and phenogroup 3 = coronary artery bypass graft with non-viable myocardial scar and reduced left ventricular ejection fraction. Using survival analysis, the occurrence of major adverse cardiovascular events (P = 0.007), cardiovascular mortality (P = 0.002) and all-cause mortality (P < 0.001) differed among the three phenogroups. Phenogroup 3 presented the worse prognosis. In each phenogroup, ischaemia was associated with major adverse cardiovascular events (phenogroup 1: hazard ratio 2.79, 95% confidence interval 1.61–4.84; phenogroup 2: hazard ratio 2.59, 95% confidence interval 1.69–3.97; phenogroup 3: hazard ratio 3.16, 95% confidence interval 1.82–5.49; all P < 0.001). Conclusions. – Cluster analysis of clinical and cardiovascular magnetic resonance variables identified three phenogroups of patients with inconclusive stress testing, with distinct prognostic profiles.

Collateral presence and extent do not predict myocardial viability and ischemia in chronic total occlusions: A stress-CMR study

Article

Sep 2022

Background: well-developed collaterals are assumed as a marker of viability and ischemia in chronic total occlusions (CTO). We aim to correlate viability and ischemia with collateral presence and extent in CTO patients by cardiac magnetic resonance (CMR). Methods: multicentre study of 150 CTO patients undergoing stress-CMR, including adenosine if normal systolic function, high-dose-dobutamine for patients with akinetic/>2 hypokinetic segments and EF ≥35%, otherwise low-dose-dobutamine (LDD); all patients underwent late gadolinium enhancement (LGE) imaging. Viability was defined as mean LGE transmurality ≤50% for adenosine, as functional improvement for dobutamine-stress-test, ischemia as ≥1.5 segments with perfusion defects outside the scar zone. Results: Rentrop 3/CC 2 defined well-developed (WD, n = 74) vs poorly-developed collaterals (PD, n = 76). Viability was equally prevalent in WD vs PD: normo-functional myocardium with ≤50% LGE in 52% vs 58% segments, p = 0.76, functional improvement by LDD in 48% vs 52%, p = 0.12. Segments with none, 1-25%,26-50%,51-75% LGE showed viability by LDD in 90%,84%,81%,61% of cases, whilst in 12% if 76-100% LGE (p < 0.01). There was no difference in WD vs PD for ischemia presence (74% vs 75%, p = 0.99) and extent (2.7 vs 2.8 segments, p = 0.77). Conclusions: in a large cohort of CTO patients, presence and extent of collaterals did not predict viability and ischemia by stress-CMR. Scar extent up to 75% LGE was still associated with viability, whereas ischemia was undetectable in 25% of patients, suggesting that the assessment of CTO patients with CMR would lead to a more comprehensive evaluation of viability and ischemia to guide revascularization.

Cardiovascular imaging techniques for the assessment of coronary artery disease

Article

Aug 2022

Coronary artery disease continues to be the leading cause of morbidity and mortality worldwide. Recent clinical trials have not demonstrated any mortality benefit of percutaneous coronary intervention compared to medical management alone in the treatment of stable angina. While invasive coronary angiography remains the gold standard for diagnosing coronary artery disease, it comes with significant risks, including myocardial infarction, stroke and death. There have been significant advances in imaging techniques to diagnose coronary artery disease in haemodynamically stable patients. The latest National Institute for Health and Care Excellence and European College of Cardiology guidelines emphasise the importance of using these imaging techniques first to inform diagnosis. This review discusses these guidelines and imaging techniques, alongside their benefits and drawbacks.

Machine-Learning Score Using Stress CMR for Death Prediction in Patients With Suspected or Known CAD

Article

Jul 2022

Background In patients with suspected or known coronary artery disease, traditional prognostic risk assessment is based on a limited selection of clinical and imaging findings. Machine learning (ML) methods can take into account a greater number and complexity of variables. Objectives This study sought to investigate the feasibility and accuracy of ML using stress CMR and clinical data to predict 10-year all-cause mortality in patients with suspected or known coronary artery disease, and compared its performance with existing clinical or CMR scores. Methods Between 2008 and 2018, a retrospective cohort study with a median follow-up of 6.0 (IQR: 5.0-8.0) years included all consecutive patients referred for stress CMR. Twenty-three clinical and 11 stress CMR parameters were evaluated. ML involved automated feature selection by random survival forest, model building with a multiple fractional polynomial algorithm, and 5 repetitions of 10-fold stratified cross-validation. The primary outcome was all-cause death based on the electronic National Death Registry. The external validation cohort of the ML score was performed in another center. Results Of 31,752 consecutive patients (mean age 63.7 ± 12.1 years and 65.7% male), 2,679 (8.4%) died with 206,453 patient-years of follow-up. The ML score (ranging from 0 to 10 points) exhibited a higher area under the curve compared with Clinical and Stress Cardiac Magnetic Resonance score, European Systematic Coronary Risk Estimation score, QRISK3 score, Framingham Risk Score, and stress CMR data alone for prediction of 10-year all-cause mortality (ML score: 0.76 vs Clinical and Stress Cardiac Magnetic Resonance score: 0.68, European Systematic Coronary Risk Estimation score: 0.66, QRISK3 score: 0.64, Framingham Risk Score: 0.63, extent of inducible ischemia: 0.66, extent of late gadolinium enhancement: 0.65; all P < 0.001). The ML score also exhibited a good area under the curve in the external cohort (0.75). Conclusions The ML score including clinical and stress CMR data exhibited a higher prognostic value to predict 10-year death compared with all traditional clinical or CMR scores.

Automatic prediction of coronary artery disease using differential evolution-based support vector machine

Article

Jun 2022

Coronary artery disease (CAD) is a common heart disease that causes the blockage of coronary arteries. To reduce fatality, an accurate diagnosis of this disease is very important. Angiography is one of the most trustworthy and conventional methods for CAD diagnosis however, it is risky, expensive, and time-consuming. Therefore in this study, we proposed a differential evolution-based support vector machine (SVM) for early and accurate detection of CAD. To improve the accuracy, different data preprocessing techniques such as one-hot encoding and normalization are also used with differential evolution for feature selection before performing classification. The proposed approach is benchmarked with the Z-Alizadeh Sani and Cleveland datasets against four state-of-the-art machine learning algorithms, and a highly cited genetic algorithm-based SVM (N2GC-nuSVM). The experimental results show that our proposed differential evolution-based SVM outperforms all the compared algorithms. The proposed method provides accuracies of 95±1% and 86.22% for predicting CAD on the benchmark datasets.

ACR Appropriateness Criteria® Chronic Chest Pain-High Probability of Coronary Artery Disease: 2021 Update

Article

May 2022
J Am Coll Radiol

Management of patients with chronic chest pain in the setting of high probability of coronary artery disease (CAD) relies heavily on imaging for determining or excluding presence and severity of myocardial ischemia, hibernation, scarring, and/or the presence, site, and severity of obstructive coronary lesions, as well as course of management and long-term prognosis. In patients with no known ischemic heart disease, imaging is valuable in determining and documenting the presence, extent, and severity of obstructive coronary narrowing and presence of myocardial ischemia. In patients with known ischemic heart disease, imaging findings are important in determining the management of patients with chronic myocardial ischemia and can serve as a decision-making tool for medical therapy, angioplasty, stenting, or surgery. This document summarizes the recent growing body of evidence on various imaging tests and makes recommendations for imaging based on the available data and expert opinion. This document is focused on epicardial CAD and does not discuss the microvascular disease as the cause for CAD. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

One-stop shop cardiovascular imaging

Article

Jan 2011

Cardiac CT, MR, SPECT, ECHO, and PET: What test, when?

Article

May 2011

Is radiation-induced cardiac toxicity reversible? Prospective evaluation of breast cancer patients enrolled in a phase-III randomized controlled trial

Article

Jan 2022
INT J RADIAT ONCOL

Objectives Myocardial perfusion defects after breast radiotherapy (RT) correlates with volume of irradiated left ventricle (LV). We aimed to determine the relationship between myocardial perfusion, LV dosimetry, and grade ≥2 latent cardiac events (LCE) in breast cancer (BC) patients undergoing adjuvant RT. Methods A randomized study evaluated the benefit of inverse-planned intensity modulated radiotherapy (IMRT) over forward-planned IMRT for radiation toxicity in breast cancer. A secondary end-point was evaluation of cardiac perfusion by single-photon emission computed tomography (SPECT) done at baseline, 6 months and 1, 2 and 5 years post RT. Receiver Operating Curve and regression analysis were done to identify association between perfusion, radiation dose-volumes and the risk of LCE. Results Of 181 patients that received adjuvant RT, 102 were left-sided and 79 were right breast cancer patients. Median follow-up was 127 months (19-160 months). A significant worsening of perfusion defects occurred post-RT in the left-sided group which improved by 1 year. LCE were 16(17.2%) in left-sided and 4(5.5%) in the right-sided groups respectively. Perfusion changes did not correlate with LCE, but LV dose-volumes correlated with LCE. Maintaining the LV volume receiving 5Gy and 10 Gy to <42cc and <38cc respectively, can reduce the risk of radiation related late cardiac events at 10 years to <5% over baseline. Conclusions and relevance RT was associated with short-term perfusion defects that improved within 1 year and was not correlated with late cardiac events. The ventricular volumes receiving 5 and 10 Gy were correlated with late cardiac events.

PET/MR: Perfusion and Viability

Chapter

Jan 2022

The clinical introduction of hybrid PET/MRI in 2010 was accompanied by great expectations. In the field of cardiovascular imaging, great opportunities were seen, especially in perfusion and viability imaging, through the combination of molecular imaging by PET and detailed, morphological imaging with high spatial resolution by MRI. However, some challenges also arose, which relate in particular to the attenuation correction of PET data using MRI data. In this chapter, we address these issues and the opportunities and possibilities of perfusion and viability imaging using hybrid PET/MRI.

The evolving role of coronary computed tomography in understanding sex differences in coronary atherosclerosis

Article

Oct 2021

Our understanding of sex differences in subclinical atherosclerosis and plaque composition and characteristics have greatly improved with the use of coronary computed tomography (CCTA) over the past years. CCTA has emerged as an important frontline diagnostic test for women, especially as we continue to understand the impact of non-obstructive atherosclerosis as well as diffuse, high risk plaque as precursors of acute cardiac events in women. Based on its ability to identify complex plaque morphology such as low attenuation plaque, high risk non calcified plaque, positive remodeling, fibrous cap, CCTA can be used to assess plaque characteristics. CCTA can avoid false positive of other imaging studies, if included earlier in assessment of ischemic symptoms. In the contemporary clinical setting, CCTA will prove useful in further understanding and managing cardiovascular disease in women and those without traditional obstructive coronary disease.

Long-Term Prognostic Value of Stress Cardiovascular Magnetic Resonance-Related Coronary Revascularization to Predict Death: A Large Registry With >200 000 Patient-Years of Follow-Up

Article

Oct 2021
CIRC-CARDIOVASC IMAG

Background: Although the benefit of coronary revascularization in patients with stable coronary disease is debated, data assessing the potential interest of stress cardiovascular magnetic resonance (CMR) to guide coronary revascularization are limited. We aimed to assess the long-term prognostic value of stress CMR-related coronary revascularization in consecutive patients from a large registry. Methods: Between 2008 and 2018, a retrospective cohort study with a median follow-up of 6.0 years (interquartile range, 5.0-8.0) included all consecutive patients referred for stress CMR. CMR-related coronary revascularization was defined by any coronary revascularization performed within 90 days after CMR. The primary outcome was all-cause death based on the National Death Registry. Results: Among the 31 762 consecutive patients (mean age 63.7±12.1 years and 65.7% males), 2679 (8.4%) died at 206 453 patient-years of follow-up. Inducible ischemia and late gadolinium enhancement by CMR were associated with death (both P<0.001). In multivariable Cox regression, inducible ischemia and late gadolinium enhancement were independent predictors of death (hazard ratio, 1.61 [99.5% CI, 1.41-1.84]; hazard ratio, 1.62 [99.5% CI, 1.41-1.86], respectively; P<0.001). In the overall population, CMR-related coronary revascularization was an independent predictor of greater survival (hazard ratio, 0.58 [99.5% CI, 0.46-0.74]; P<0.001). In 1680, 1:1 matched patients using a limited number of variables (840 revascularized, 840 nonrevascularized), CMR-related revascularization was associated with a lower incidence of death in patients with severe inducible ischemia (≥6 segments, P<0.001) but showed no benefit in patients with mild or moderate ischemia (<6 segments, P=0.109). Using multivariable analysis in the propensity-matched population, CMR-related revascularization remained an independent predictor of a lower incidence of all-cause mortality (hazard ratio, 0.66 [99.5% CI, 0.54-0.80], P<0.001). Conclusions: In this large observational series of consecutive patients, stress perfusion CMR had important incremental long-term prognostic value to predict death over traditional risk factors. CMR-related revascularization was associated with a lower incidence of death in patients with severe ischemia.

Deep Learning Algorithm Predicts Angiographic Coronary Artery Disease in Stable Patients Using Only a Standard 12-Lead Electrocardiogram

Article

Aug 2021
CAN J CARDIOL

Background Current electrocardiogram analysis algorithms cannot predict the presence of coronary artery disease (CAD), especially in stable patients. This study assessed the ability of an artificial intelligence algorithm (ECGio) to predict the presence, location, and severity of coronary artery lesions in an unselected stable patient population. Methods A cohort of 1659 stable outpatients were randomly divided into training (86%) and validation (14%) subsets, maintaining population characteristics. ECGio was trained and validated using electrocardiograms paired with retrospectively-collected angiograms. Coronary artery lesions were classified in two analyses. The primary classification was no/mild (<30% diameter stenosis [DS]) vs moderate (30-70% DS) vs severe (≥70% DS) CAD. The secondary classification was yes/no based on ≥50% DS in any vessel. Results In the primary analysis, 22 had no angiographic CAD and were grouped Mild CAD (56 patients, DS <30%), 31 had Moderate CAD (DS 30-70%), and 113 had severe CAD (DS ≥70%). Weighted average sensitivity was 93.2% and weighted average specificity was 96.4%. In the secondary analysis, 93 had significant CAD; and 128 did not. There was sensitivity of 93.1% and specificity of 85.6% in determining the presence of clinically significant disease (≥50% DS) in any vessel. ECGio was able to predict stenosis with average vessel error in the LAD of 18%, the LCX of 19%, the RCA of 18%, and the LM of 8%. Conclusion This study strongly suggests that it is possible to utilize an artificial intelligence algorithm to determine the presence and severity of CAD in stable patients using data from a 12-lead electrocardiogram.

Myocardial Perfusion and Viability Imaging in Coronary Artery Disease: Clinical Value in Diagnosis, Prognosis, and Therapeutic Guidance

Article

Full-text available

Apr 2021
AM J MED

Coronary artery disease is a leading cause of morbidity and mortality worldwide. Non-invasive imaging tests play a significant role in diagnosing coronary artery disease, as well as risk stratification and guidance for revascularization. Myocardial perfusion imaging, including single photon emission computed tomography and positron emission tomography, has been widely employed. In this review, we will review test accuracy, and clinical significance of these methods for diagnosing and managing coronary artery disease. We will further discuss the comparative usefulness of other non-invasive tests - stress echocardiography, coronary computed tomography angiography and cardiac magnetic resonance imaging - in the evaluation of ischemia and myocardial viability.

Contemporary advances in medical imaging

Chapter

Jan 2021

Contemporary advances in imaging technology have revolutionized the field of cardiovascular disease with improved detection of disease states coupled with innovative therapeutic interventions. As a result, clinicians have a plethora of diagnostic tools including echocardiography, cardiac computed tomography (CT), cardiac magnetic resonance (CMR), and nuclear imaging. Echocardiography is widely available and provides a comprehensive assessment of cardiac anatomy, function, and hemodynamics. Complementary to echocardiography, CMR provides accurate cardiac volumes, function, and noninvasive hemodynamic assessment of valvular disease and flows. Innovations in cardiac CT have provided the ability to noninvasively image the coronary arteries, as well as cardiac structures that are useful in preprocedural planning for cardiac surgery or transcatheter heart interventions. Nuclear imaging has previously been the mainstay of ischemia assessment in coronary artery disease using exercise or vasodilator testing. Advances in CT-fractional flow reserve, CMR with scar imaging, and positron emission tomography (PET) with coronary flow reserve provide an ability to detect ischemia while extracting vital prognostic data for each patient. Recent advances in technetium-99m pyrophosphate, PET, and CMR have improved the ability to noninvasively detect cardiomyopathies such as cardiac amyloidosis, sarcoidosis, and inflammatory or infiltrative diseases. Nevertheless, each imaging modality is complementary to each other and often a multimodality patient-specific approach is needed. Furthermore, the integration of artificial intelligence within a clinical workflow allows for a safer, time and cost-effective approach to clinical practice and management.

Myocardial perfusion scintiqraphy: The evidence

Article

Full-text available

Aug 2004

Dipyridamole magnetic resonance imaging: A comparison with thallium-201 emission tomography

Article

Full-text available

Jan 1991
Br Heart J

Limitation of space and motion artefact make magnetic resonance imaging during dynamic exercise difficult. Pharmacological stress with dipyridamole can be used as an alternative to exercise for thallium scanning. Forty patients with a history of angina and an abnormal exercise electrocardiogram were studied by dipyridamole thallium myocardial perfusion tomography and dipyridamole magnetic resonance wall motion imaging with a cine gradient refocused sequence. Images for both scans were obtained in the oblique horizontal and vertical long axis and short axis planes before and after pharmacological stress with dipyridamole. The myocardium was divided into nine segments for direct comparison of perfusion with wall motion. Segments were assessed visually into grades--normal, hypokinesis or reduced perfusion, and akinesis or very reduced perfusion. After dipyridamole there were reversible wall motion abnormalities in 24 (62%) of 39 patients with coronary artery disease and 24 (67%) of 36 patients with reversible thallium defects. The site of wall motion deterioration was always the site of a reversible thallium defect. Thallium defects affecting more than two segments were always associated with wall motion deterioration but most single segment thallium defects were undetected by magnetic resonance imaging. There was a significant correlation between detection of wall motion abnormality, the angiographic severity of coronary artery disease, and the induction of chest pain by dipyridamole. There were no significant differences in ventricular volume or ejection fraction changes after dipyridamole between the groups with and without detectable reversible wall motion changes but the normalised magnetic resonance signal intensity of the abnormally moving segments was significantly less than the signal intensity of the normal segments. In nine patients the change was apparent visually and it was maximal in the subendocardial region. Magnetic resonance imaging of reversible wall motion abnormalities in patients with coronary artery disease is feasible during pharmacological stress with dipyridamole and may be associated with a reduced magnetic resonance signal. The failure to show wall motion abnormalities in all cases of reversible thallium defects may be because the defect was small or because dipyridamole caused perfusion defects in the absence of myocardial ischaemia.

Real-Time MR Image Acquisition during High-Dose Dobutamine Hydrochloride Stress for Detecting Left Ventricular Wall-Motion Abnormalities in Patients with Coronary Arterial Disease1

Article

Full-text available

Oct 2002

To compare the accuracy of real-time magnetic resonance (MR) imaging with that of standard echo-planar MR imaging for detecting myocardial wall-motion abnormalities at rest and during dobutamine hydrochloride-induced stress in patients with coronary arterial disease. In 22 patients with coronary arterial disease, left ventricular wall motion was examined at rest and during dobutamine hydrochloride stress, by using echo-planar MR imaging and a new technique with real-time segmented k-space turbo gradient-echo echo-planar MR imaging (repetition time, 16.5 msec; echo time, 6.8 msec). Wall-motion abnormalities were determined visually for each perfusion territory, and Cohen kappa coefficients were calculated for real-time imaging in comparison with echo-planar imaging. Coronary angiography was performed in all patients. Sensitivity and specificity for real-time and echo-planar imaging were calculated for detecting significant coronary arterial stenosis. kappa values for detecting wall-motion abnormalities at real-time imaging, in comparison with echo-planar MR imaging, were 0.97 at rest and 0.94 at maximum dobutamine hydrochloride stress. At comparison with those of angiography, the sensitivity and specificity for detecting significant coronary arterial stenosis were 88% (14 of 16 patients) and 83% (five of six patients), respectively, for echo-planar imaging and 81% (13 of 16 patients) and 83% (five of six patients), respectively, for real-time imaging. Real-time MR imaging is possible under stress conditions and allows accurate detection of wall-motion abnormalities.

Dobutamine Induced Myocardial Perfusion Reserve Index with Cardiovascular MR in Patients with Coronary Artery Disease

Article

Full-text available

Jan 2002

Currently, adenosine or dipyridamole is commonly used for the assessment of perfusion reserve. With intolerance to these agents, dobutamine can be used alternatively or it can be used for a combined examination of wall motion and perfusion. The aim of the study was to analyze the feasibility of cardiovascular magnetic resonance (CMR) to assess perfusion reserve with dobutamine. Alterations of myocardial perfusion were noninvasively assessed in 23 patients with and 4 without significant coronary artery disease by calculation of a myocardial perfusion reserve index from the upslope of the signal intensity curves of a first pass gadolinium bolus before and during dobutamine infusion (20 micrograms/min/kg). An ischemic threshold value of perfusion reserve index was determined from patients without significant coronary artery disease. Significant differences were found between ischemic and remote to ischemic segments in patients with single vessel disease (0.90 +/- 0.18 vs. 1.73 +/- 0.32, p < 0.0001). Differences between nonischemic segments in patients without and ischemic segments in patients with coronary artery disease were significant (2.0 +/- 0.39 vs. 0.97 +/- 0.20, p < 0.001). A cut-off value for myocardial perfusion reserve index of 1.22 for the detection of significant coronary artery stenosis yielded a sensitivity, specificity, and diagnostic accuracy of 81, 73, and 77%, respectively. Dobutamine MR is feasible in the evaluation of myocardial perfusion and can be used for the detection of myocardial ischemia alternatively to adenosine or dipyridamole in patients with coronary artery disease.

Magnetic Resonance Perfusion Measurements for the Noninvasive Detection of Coronary Artery Disease

Article

Full-text available

Aug 2003
CIRCULATION

With MRI, an index of myocardial perfusion reserve (MPRI) can be determined. We assessed the value of this technique for the noninvasive detection of coronary artery disease (CAD) in patients with suspected CAD. Eighty-four patients referred for a primary diagnostic coronary angiography were examined with a 1.5 T MRI tomograph (Philips-ACS). For each heartbeat, 5 slices were acquired during the first pass of 0.025 mmol gadolinium-diethylenetriamine pentaacetic acid/kg body weight before and during adenosine vasodilation by using a turbo-gradient echo/echo-planar imaging-hybrid sequence. MPRI was determined from the alteration of the upslope of the myocardial signal intensity curves for 6 equiangular segments per slice. Receiver operating characteristics were performed for different criteria to differentiate ischemic and nonischemic segments. Prevalence of CAD was 51%. Best results were achieved when only the 3 inner slices were assessed and a threshold value of 1.1 was used for the second smallest value as a marker for significant CAD. This approach yielded a sensitivity of 88%, specificity of 90%, and accuracy of 89%. The determination of MPRI with MRI yields a high diagnostic accuracy in patients with suspected CAD.

The Impact of Myocardial Flow Reserve on the Detection of Coronary Artery Disease by Perfusion Imaging Methods: An NHLBI WISE Study

Article

Full-text available

Jul 2003

Myocardial flow reserve (MFR) is not routinely assessed in myocardial perfusion imaging (MPI) studies but has been hypothesized to affect test accuracy when assessing disease severity by coronary vessel lumenography. Magnetic resonance imaging (MRI) is an emerging diagnostic technique that can both perform MPI and assess MFR. We studied women (n = 184) enrolled in the Women's Ischemia Syndrome Evaluation (WISE) study with symptoms suggesting ischemic heart disease. Tests performed were coronary angiography and MPI by both MR and gated radionuclide single photon emission computed tomography (gated-SPECT). The MFR index was calculated using the MR data acquired at baseline and under vasodilation (dipyridamole) conditions. The study was structured with a pilot and an implementation phase. During the pilot phase (n = 46) data were unmasked and an MFR threshold was defined to divide patients into those with an adequate (AMFRI) or inadequate (IMFRI) MFR index. During the implementation phase, the MFR index threshold was prospectively applied to patients (n = 138). In the implementation phase, MPI ischemia detection accuracy compared to severe (> or = 70%) coronary artery diameter narrowing by angiography was higher in the AMFRI vs. the IMFRI group for MRI (86% vs. 70%, p < 0.05) and gated-SPECT (89% vs. 67%, p < 0.01). The IMFRI group (n = 55, 30% of study population) had a higher resting rate-pressure product compared with the AMFRI group (10,599 +/- 2871 vs. 9378 +/- 2447 bpm mm Hg, p < 0.01), consistent with higher resting myocardial flow. When compared with each other, MRI and gated-SPECT MPI showed no difference in accuracy among MFR groups. Myocardial perfusion patterns in the IMFRI group may have resulted in atypical perfusion patterns, which either masked or mimicked epicardial coronary artery disease.

Whiting P, Rutjes AWS, Reitsma JB, Bossuyt PMM, Kleijnen JThe development of QUADAS: a tool for the quality assessment of studies of diagnostic accuracy included in systematic reviews. BMC Med Res Methodol 3: 1-13

Article

Full-text available

Dec 2003
BMC MED RES METHODOL

In the era of evidence based medicine, with systematic reviews as its cornerstone, adequate quality assessment tools should be available. There is currently a lack of a systematically developed and evaluated tool for the assessment of diagnostic accuracy studies. The aim of this project was to combine empirical evidence and expert opinion in a formal consensus method to develop a tool to be used in systematic reviews to assess the quality of primary studies of diagnostic accuracy. We conducted a Delphi procedure to develop the quality assessment tool by refining an initial list of items. Members of the Delphi panel were experts in the area of diagnostic research. The results of three previously conducted reviews of the diagnostic literature were used to generate a list of potential items for inclusion in the tool and to provide an evidence base upon which to develop the tool. A total of nine experts in the field of diagnostics took part in the Delphi procedure. The Delphi procedure consisted of four rounds, after which agreement was reached on the items to be included in the tool which we have called QUADAS. The initial list of 28 items was reduced to fourteen items in the final tool. Items included covered patient spectrum, reference standard, disease progression bias, verification bias, review bias, clinical review bias, incorporation bias, test execution, study withdrawals, and indeterminate results. The QUADAS tool is presented together with guidelines for scoring each of the items included in the tool. This project has produced an evidence based quality assessment tool to be used in systematic reviews of diagnostic accuracy studies. Further work to determine the usability and validity of the tool continues.

Myocardial perfusion scintigraphy: The evidence

Article

Full-text available

Mar 2004

This review summarises the evidence for the role of myocardial perfusion scintigraphy (MPS) in patients with known or suspected coronary artery disease. It is the product of a consensus conference organised by the British Cardiac Society, the British Nuclear Cardiology Society and the British Nuclear Medicine Society and is endorsed by the Royal College of Physicians of London and the Royal College of Radiologists. It was used to inform the UK National Institute of Clinical Excellence in their appraisal of MPS in patients with chest pain and myocardial infarction. MPS is a well-established, non-invasive imaging technique with a large body of evidence to support its effectiveness in the diagnosis and management of angina and myocardial infarction. It is more accurate than the exercise ECG in detecting myocardial ischaemia and it is the single most powerful technique for predicting future coronary events. The high diagnostic accuracy of MPS allows reliable risk stratification and guides the selection of patients for further interventions, such as revascularisation. This in turn allows more appropriate utilisation of resources, with the potential for both improved clinical outcomes and greater cost-effectiveness. Evidence from modelling and observational studies supports the enhanced cost-effectiveness associated with MPS use. In patients presenting with stable or acute chest pain, strategies of investigation involving MPS are more cost-effective than those not using the technique. MPS also has particular advantages over alternative techniques in the management of a number of patient subgroups, including women, the elderly and those with diabetes, and its use will have a favourable impact on cost-effectiveness in these groups. MPS is already an integral part of many clinical guidelines for the investigation and management of angina and myocardial infarction. However, the technique is underutilised in the UK, as judged by the inappropriately long waiting times and by comparison with the numbers of revascularisations and coronary angiograms performed. Furthermore, MPS activity levels in this country fall far short of those in comparable European countries, with about half as many scans being undertaken per year. Currently, the number of MPS studies performed annually in the UK is 1,200/million population/year. We estimate the real need to be 4,000/million/year. The current average waiting time is 20 weeks and we recommend that clinically appropriate upper limits of waiting time are 6 weeks for routine studies and 1 week for urgent studies.

Combined Coronary and Perfusion Cardiovascular Magnetic Resonance for the Assessment of Coronary Artery Stenosis

Article

Full-text available

Feb 2004

The purpose of this study was to evaluate the feasibility and accuracy of combined coronary and perfusion cardiovascular magnetic resonance (CMR) in the assessment of coronary artery stenosis. Thirty-five consecutive patients (27 men, eight women, age range 34-81 years), undergoing cardiac catheterization, were assessed with 3D coronary CMR and rest-stress perfusion CMR. Significant coronary stenosis was determined by vessel narrowing or signal loss with coronary CMR, and by abnormal contrast enhancement with perfusion CMR. Coronary artery diameter stenosis greater than 50% was considered significant with conventional cardiac catheterization. Seventeen patients had significant coronary artery disease, and in these there were 35 significant stenoses on cardiac catheterization. All left main stem arteries were normal on both cardiac catheterization and coronary CMR. For the diagnosis of coronary artery stenosis, coronary CMR had a sensitivity of 92% for the left anterior descending artery (LAD), 79% for the right coronary artery (RCA), but only 13% for the circumflex coronary artery (LCX). Perfusion CMR had corresponding sensitivities of 69%, 86%, and 63%, respectively. For all arteries the accuracies for coronary and perfusion CMR were 67% and 72%, respectively. Combining coronary and perfusion CMR improved the accuracy to 77%. These data demonstrate that in patients with suspected coronary artery disease, combined coronary and perfusion CMR is feasible, increases the accuracy of detection of significant coronary stenosis, and offers the possibility of combined anatomical and hemodynamic assessment of coronary artery stenosis.

Cardiac imaging in coronary artery disease: Differing modalities

Article

Full-text available

Sep 2005
HEART

Coronary artery disease (CAD) remains one of the leading causes of morbidity and mortality worldwide. Moreover, the disease is reaching endemic proportions and will put an enormous strain on health care economics in the near future. Non-invasive testing is important to exclude CAD with a high certainty on the one hand, and to detect CAD with its functional consequences at an early stage, to guide optimal patient management, on the other hand. For these purposes, non-invasive imaging techniques have been developed and used extensively over the last years. Currently, the main focus of non-invasive imaging for diagnosis of CAD is twofold: (1) functional imaging , assessing the haemodynamic consequences of obstructive coronary artery disease; and (2) anatomical imaging , visualising non-invasively the coronary artery tree. For functional imaging, nuclear cardiology, stress echocardiography, and magnetic resonance imaging (MRI) are used, whereas for anatomical imaging or non-invasive angiography, MRI, multislice CT (MSCT), and electron beam CT (EBCT) are used. This manuscript will update the reader on the current status of non-invasive imaging, with a special focus on functional imaging versus anatomical imaging for the detection of CAD. The accuracies of the different imaging modalities are illustrated using pooled analyses of the available literature data when available. ### What information does functional imaging provide? The hallmark of functional imaging is the detection of CAD by assessing the haemodynamic consequences of CAD rather than by direct visualisation of the coronary arteries. For this purpose, regional perfusion or wall motion abnormalities are induced (or worsened) during stress, reflecting the presence of stress induced ischaemia. Ischaemia induction is based on the principle that although resting myocardial blood flow in regions supplied by stenotic coronary arteries is preserved, the increased flow demand during stress cannot be met, resulting in a sequence of events referred to as “the ischaemic cascade”.1 Initially perfusion abnormalities are …

Determination of interobserver variability for identifying inducible left ventricular wall motion abnormalities during dobutamine stress magnetic resonance imaging

Article

Full-text available

Jun 2006

To determine the interobserver variability for identifying inducible left ventricular (LV) wall motion abnormalities during high-dose dobutamine/atropine stress cardiovascular magnetic resonance (DSMR). Four readers from various institutions were supplied with the image data from 150 consecutive DSMR examinations and asked to grade wall motion and image quality throughout graded doses of dobutamine infusion administered to achieve 85% of the maximum age-predicted heart rate. Inducible ischaemia was identified if more than one segment demonstrated a new or worsening LV wall motion abnormality, and significant stenosis was defined as > or =50% luminal diameter reduction by quantitative contrast coronary angiography. Seventy-seven patients (51%) had luminal narrowings > or =50%. Diagnostic performance (sensitivity, specificity, diagnostic accuracy) of all readers was 78.2, 87.0 and 82.5%. Disagreement between two readers occurred in every seventh examination. Agreement on the presence or absence of inducible wall motion abnormalities was moderate (mean kappa value 0.59, range 0.52-0.76). Diagnostic performance and disagreement were independent of the presence of luminal narrowings > or =50% or the number of diseased coronary vessels. Image quality was regarded excellent in 89.3% of standard views. In the setting of multiple observers from different institutions performing a diagnostic reading of DSMR examinations carried out at a single centre, the interobserver variability was low for identifying inducible LV wall motion abnormalities indicative of coronary arterial luminal narrowings > or =50%.

ACCF/ACR/SCCT/SCMR/ASNC/NASCI/SCAI/SIR 2006 appropriateness criteria for cardiac computed tomography and cardiac magnetic resonance imaging: a report of the American College of Cardiology Foundation Quality Strategic Directions Committee Appropriateness Criteria Working Group, American College of Radiology, Society of Cardiovascular Computed Tomography, Society for Cardiovascular Magnetic Resonance, American Society of Nuclear Cardiology, North American Society for Cardiac Imaging, Society for C

Article

Full-text available

Nov 2006

Under the auspices of the American College of Cardiology Foundation (ACCF) together with key specialty and subspecialty societies, appropriateness reviews were conducted for 2 relatively new clinical cardiac imaging modalities, cardiac computed tomography (CCT) and cardiac magnetic resonance (CMR) imaging. The reviews assessed the risks and benefits of the imaging tests for several indications or clinical scenarios and scored them based on a scale of 1 to 9, where the upper range (7 to 9) implies that the test is generally acceptable and is a reasonable approach, and the lower range (1 to 3) implies that the test is generally not acceptable and is not a reasonable approach. The mid-range (4 to 6) indicates an uncertain clinical scenario. The indications for these reviews were drawn from common applications or anticipated uses, as few clinical practice guidelines currently exist for these techniques. These indications were reviewed by an independent group of clinicians and modified by the Working Group, and then panelists rated the indications based on the ACCF Methodology for Evaluating the Appropriateness of Cardiovascular Imaging, which blends scientific evidence and practice experience. A modified Delphi technique was used to obtain first and second round ratings of clinical indications after the panelists were provided with a set of literature reviews, evidence tables, and seminal references. The final ratings were evenly distributed among the 3 categories of appropriateness for both CCT and CMR. Use of tests for structure and function and for diagnosis in symptomatic, intermediate coronary artery disease (CAD) risk patients was deemed appropriate, while repeat testing and general screening uses were viewed less favorably. It is anticipated that these results will have a significant impact on physician decision making and performance, reimbursement policy, and future research directions.

Accelerated 4D Dobutamine Stress MR Imaging with k-t BLAST: Feasibility and Diagnostic Performance 1

Article

Full-text available

Dec 2006

To prospectively determine feasibility and diagnostic performance (with angiography as reference standard) of k-space and time (k-t) broad-use linear acquisition speed-up technique (k-t BLAST) cine imaging during dobutamine stress for identification of inducible cardiac wall motion abnormalities. The study was conducted according to standards of the Charité and Virchow-Klinikum Ethics Committee. Patients gave written consent. Dobutamine stress magnetic resonance (MR) imaging was conducted in 65 patients (mean age, 63 years +/- 9 [standard deviation]; 49 men) with conventional cine steady-state free precession (SSFP). Accelerated four-dimensional (4D) k-t BLAST single-breath-hold imaging with complete left ventricular (LV) coverage was also performed at rest and during stress. For the cine SSFP and accelerated cine techniques, duration of imaging at rest and LV end-diastolic volume and ejection fraction were assessed. Segmental agreement for resting and inducible wall motion abnormalities was determined. In a subgroup (n = 40), direct comparison between SSFP and accelerated cine was performed for coronary stenosis detection. A paired Student t test was used to assess significance of continuous variables. Pearson correlation was used to test correlation between the techniques. Sensitivity, specificity, and diagnostic accuracy were calculated (standard definitions). For quantitative measurement of agreement, Cohen kappa was applied. For accelerated cine, imaging duration at rest was shortened by 40%. Correlations between cine SSFP and accelerated cine for LV parameters were 135 mL +/- 37 versus 129 mL +/- 31 (r = 0.89) for end-diastolic volume and 59% +/- 8 versus 58% +/- 7 (r = 0.95) for ejection fraction. kappa Values for segmental wall motion at rest and stress ranged from 0.77 to 0.91. Sensitivity, specificity, and diagnostic accuracy for coronary stenosis (>or=50%) detection based on arterial territory were 82%, 87%, and 86%, respectively, for cine SSFP and 82%, 86%, and 85%, respectively, for accelerated cine imaging. Accelerated 4D k-t BLAST wall motion imaging at rest and at dobutamine stress is rapid and feasible; LV measurements were nearly identical between the imaging approaches. Segmental wall motion analysis at rest and at stress show excellent agreement and reliable depiction of myocardial territories supplied by coronary arteries with 50% or more luminal narrowing.

The development of QUADAS: A tool for the quality assessment of studies of diagnostic accuracy included in systematic reviews

Article

Nov 2003
BMC MED RES METHODOL

In the era of evidence based medicine, with systematic reviews as its cornerstone, adequate quality assessment tools should be available. There is currently a lack of a systematically developed and evaluated tool for the assessment of diagnostic accuracy studies. The aim of this project was to combine empirical evidence and expert opinion in a formal consensus method to develop a tool to be used in systematic reviews to assess the quality of primary studies of diagnostic accuracy. METHODS: We conducted a Delphi procedure to develop the quality assessment tool by refining an initial list of items. Members of the Delphi panel were experts in the area of diagnostic research. The results of three previously conducted reviews of the diagnostic literature were used to generate a list of potential items for inclusion in the tool and to provide an evidence base upon which to develop the tool. RESULTS: A total of nine experts in the field of diagnostics took part in the Delphi procedure. The Delphi procedure consisted of four rounds, after which agreement was reached on the items to be included in the tool which we have called QUADAS. The initial list of 28 items was reduced to fourteen items in the final tool. Items included covered patient spectrum, reference standard, disease progression bias, verification bias, review bias, clinical review bias, incorporation bias, test execution, study withdrawals, and indeterminate results. The QUADAS tool is presented together with guidelines for scoring each of the items included in the tool. CONCLUSIONS: This project has produced an evidence based quality assessment tool to be used in systematic reviews of diagnostic accuracy studies. Further work to determine the usability and validity of the tool continues

Cardiac perfusion magnetic resonance imaging for the quantitative assessment of symptomatic coronary artery disease. A comparison with pressure derived fractional flow reserve, coronary angiography and SPECT

Conference Paper

Aug 2004

Comparison between contrast enhanced magnetic resonance imaging and positron emission tomography for the assessment of myocardial flow reserve.

Article

May 2002

Assessment of non-ST-segment elevation acute coronary syndromes with cardiac magnetic resonance imaging

Article

Apr 2005

Echo‐planar magnetic resonance myocardial perfusion imaging: Parametric map analysis and comparison with thallium SPECT

Article

Feb 2001
J MAGN RESON IMAGING

Magnetic resonance (MR) perfusion FLASH imaging has been used for assessing coronary artery disease (CAD). Echo-planar MR techniques have advantages in speed and in making MR perfusion imaging results more clinically accessible through parametric maps, but have not been previously assessed. We implemented a spin-echo, echo-planar MR technique and applied it at rest and during adenosine stress in 26 patients with CAD and abnormal thallium single-photon-emission computed tomography (SPECT), and analyzed the results by using a newly developed parametric map analysis of time to peak, peak intensity, and slope of contrast washin. The results were compared with the results of conventional visual analysis of the perfusion cine series. For detecting abnormal coronary territories, MR and SPECT were comparable for sensitivity, specificity, and accuracy (thallium, 70%, 78%, and 73%; MR, 79% 83%, and 80%; P = NS). There was good agreement between thallium and MR during stress (kappa = 0.49), but defects were larger by MR (2.4 vs. 3.1 segments for slope; P < 0.01). Additional segments were detected at rest by MR (58 for slope vs. 25 for thallium), which correlated with areas that became abnormal with stress in the thallium (sensitivity, 100%; specificity, 63%). The parametric maps were easier and faster to interpret than review of the original first-pass series of images (χ2 = 10.8; P < 0.04). The diagnostic performance of echo-planar perfusion MR and SPECT was similar, and combining the results with parametric mapping was useful for interpretation and considerably improved data display for clinical interpretation. MR, however, was faster and yielded images of higher resolution with no radiation burden. In multislice mode, these new MR techniques may have clinical value. J. Magn. Reson. Imaging 2001;13:192–200. © 2001 Wiley-Liss, Inc.

Magnetic Resonance Imaging in Coronary Artery Disease

Chapter

Jul 2011

The management of patients with chest pain requires answers to two principal questions. Firstly, is myocardial ischemia the cause of the pain and, if so, where is it and how extensive is it? Secondly, what form of treatment is most likely to abolish symptoms and improve prognosis, in particular, is coronary arteriography required prior to a revascularization procedure?

Magnetic resonance imaging during dobutamine stress in coronary artery disease

Article

Aug 1992
AM J CARDIOL

Cine magnetic resonance imaging (MRI) provides a tomographic method of assessing regional ventricular function in any desired plane. It has not been possible to obtain adequate images during dynamic exercise, and this has limited its value in patients with coronary artery disease (CAD). Therefore, an infusion of dobutamine was used to study 25 patients with exertional chest pain and abnormal exercise electrocardiograms. Areas of abnormal wall motion were compared with areas of abnormal myocardial perfusion imaged by dobutamine thallium emission tomography and with coronary arteriography. Twenty-two patients had significant CAD. Twenty-one (96%) of these patients had reversible myocardial ischemia shown by dobutamine thallium tomography, and 20 (91%) had reversible wall motion abnormalities shown by dobutamine MRI. Comparison of abnormal segments of perfusion and wall motion showed 96% agreement at rest, 90% agreement during stress, and 91% agreement for the assessment of functional reversibility. The normalized magnetic resonance signal intensity of the ischemic segments showed a small but significant reduction when compared with that of normal segments (-67 units [9.2%]; p less than 0.05). Dobutamine infusion was well-tolerated, despite causing chest discomfort in 24 patients (96%). Nine patients (36%) developed a minor dysrhythmia that was usually ventricular premature complexes, but this did not limit infusion, and other side effects were mild. The short plasma half-life of dobutamine makes it ideal as a stress agent for imaging techniques (such as MRI), and these results suggest that it is more effective in the provocation of wall motion abnormalities than is dipyridamole in patients with CAD.

Feasibility of high-dose dipyridamole-magnetic resonance imaging for detection of coronary artery disease and comparison with coronary angiography

Article

Feb 1992
AM J CARDIOL

To assess the feasibility, safety and usefulness of gradient-echo magnetic resonance imaging (MRI) combined with pharmacologic stress testing for the detection of coronary artery disease, 23 patients without previous myocardial infarction but with significant stenosis (greater than 70% diameter stenosis) of greater than or equal to 1 major coronary artery were selected for dipyridamole-MRI stress testing. Each patient underwent MRI at rest, and high-dose dipyridamole-MRI (0.75 mg/kg over 10 minutes) of corresponding basal and midventricular short-axis tomograms. Additionally, these patients performed symptom-limited exercise stress tests. All short-axis tomograms were evaluated on a standardized segmental basis by grading each segment as normal, hypokinetic, akinetic or dyskinetic. Dipyridamole-MRI was considered pathologic if segmental wall motion deteriorated by greater than or equal to 1 grade after dipyridamole. For comparison with coronary angiography, segmental wall motion gradings were related to the respective coronary artery territories in the short-axis plane. Pathologic dipyridamole-MRI was obtained in 18 of 23 (78%) patients. For 1- and 2-vessel diseases, sensitivity was 69 and 90%, respectively. Exercise stress tests were pathologic in 14 of 23 (66%) patients. For 1- and 2-vessel diseases, sensitivity of exercise stress test was 58% (7 of 12 patients) and 77% (7 of 9), respectively. Sensitivity/specificity of dipyridamole-MRI for the localization of the stenosed coronary artery was 78/100% for left anterior descending, 73/100% for left circumflex, and 88/87% for right coronary artery stenoses. It is concluded that dipyridamole-MRI is a feasible nonexercise-dependent test for detection and localization of functionally significant coronary artery disease.

Measuring the Accuracy of Diagnostic Systems

Article

Jul 1988

John A. Swets

Diagnostic systems of several kinds are used to distinguish between two classes of events, essentially "signals" and "noise". For them, analysis in terms of the "relative operating characteristic" of signal detection theory provides a precise and valid measure of diagnostic accuracy. It is the only measure available that is uninfluenced by decision biases and prior probabilities, and it places the performances of diverse systems on a common, easily interpreted scale. Representative values of this measure are reported here for systems in medical imaging, materials testing, weather forecasting, information retrieval, polygraph lie detection, and aptitude testing. Though the measure itself is sound, the values obtained from tests of diagnostic systems often require qualification because the test data on which they are based are of unsure quality. A common set of problems in testing is faced in all fields. How well these problems are handled, or can be handled in a given field, determines the degree of confidence that can be placed in a measured value of accuracy. Some fields fare much better than others.

Magnetic resonance imaging during dobutamine stress for detection and localization of coronary artery disease. Quantitative wall motion analysis using a modification of the centerline method

Article

Aug 1994

Quantitative measurement of wall motion is essential to assess objectively the functional significance of coronary artery disease. We developed a quantitative wall thickening analysis on stress magnetic resonance images. This study was designed to assess the clinical value of magnetic resonance imaging (MRI) during dobutamine stress for detection and localization of myocardial ischemia in patients with suspected coronary artery disease. Thirty-nine consecutive patients with clinically suspected coronary artery disease referred for coronary arteriography and 10 normal volunteers underwent gradient-echo MRI at rest and during peak dobutamine stress (infusion rate, 20 micrograms.kg-1.min-1). MRI was performed in the short-axis plane at four adjacent levels. Display in a cine loop provided a qualitative impression of regional wall motion (cine MRI). A modification of the centerline method was applied for quantitative wall motion analysis by means of calculation of percent systolic wall thickening. Short-axis cine MRI images were analyzed at 100 equally spaced chords constructed perpendicular to a centerline drawn midway between the end-diastolic and end-systolic contours. Dobutamine MRI was considered positive for coronary artery disease if the percent systolic wall thickening of more than four adjacent chords was < 2 SD below the mean values obtained from the normal volunteers. The overall sensitivity of dobutamine MRI for the detection of significant coronary artery disease (diameter stenosis > or = 50%) was 91% (30 of 33), specificity was 80% (5 of 6), and accuracy was 90% (35 of 39). The sensitivity for identifying one-vessel disease was 88% (15 of 17), for two-vessel disease 91% (10 of 11), and for three-vessel disease 100% (5 of 5). The sensitivity for detection of individual coronary artery lesions was 75% for the left anterior descending coronary artery, 87% for the right coronary artery, and 63% for the left circumflex coronary artery. Dobutamine MRI clearly identifies wall motion abnormalities by quantitative analysis using a modification of the centerline method. Dobutamine MRI is an accurate method for detection and localization of myocardial ischemia and may emerge as a new noninvasive approach for evaluation of patients with known or suspected coronary artery disease.

Coronary artery disease: Findings with GRE MR imaging and Tc-99m- methoxyisobutyl-isonitrile SPECT during simultaneous dobutamine stress

Article

Nov 1994

This study compared gradient-recalled echo (GRE) magnetic resonance (MR) imaging with technetium-99m-methoxyisobutyl isonitrile (MIBI) single photon emission computed tomography (SPECT) during the same dobutamine stress for the localization of coronary artery stenoses. In 35 consecutive patients (28 men and seven women, aged 41-79 years) with angiographically documented coronary artery disease, corresponding GRE MR images and SPECT tomograms were acquired at rest and during dobutamine infusion and were evaluated for regional wall motion or perfusion abnormalities. Images in both examinations could be analyzed in 32 of 35 (91%) patients. Wall motion or perfusion abnormalities were observed in 27 of 32 (84%) GRE MR imaging and in 28 of 32 (87%) SPECT examinations. Sensitivity and specificity of dobutamine GRE MR imaging and dobutamine SPECT for the localization of left anterior descending coronary artery stenoses were 74% and 100% versus 70% and 100% for the combined left circumflex and right coronary artery perfusion territories. GRE MR imaging and SPECT have a high concordance with respect to the detection of a dobutamine-induced ischemic response.

Dobutamine stress MRI for detection of coronary artery disease

Article

Aug 1993
J AM COLL CARDIOL

The clinical value of cine magnetic resonance imaging (MRI) during dobutamine stress for detection of coronary artery disease was evaluated in 45 patients with chest pain who were admitted for coronary arteriography. Development of stress-induced wall motion asynergy is considered an early and reliable sign of myocardial ischemia preceding electrocardiographic (ECG) changes and angina. As physical exercise during MRI is difficult because of motion artifacts and space restriction, dobutamine infusion was used to induce cardiovascular stress. Cine MRI tomograms were obtained in six adjacent short-axis planes. After baseline acquisition, dobutamine was administered to a maximal dose of 20 micrograms/kg per min. Both at rest and during peak dobutamine stress, magnetic resonance images were displayed in a cinematographic loop to assess regional wall motion qualitatively. Results of dobutamine MRI were considered positive for coronary artery disease if any new or worsening wall motion abnormality developed. Immediately after MRI at peak dobutamine infusion, dobutamine electrocardiography was performed outside the magnetic environment. In addition, all patients performed symptom-limited exercise electrocardiography. Significant coronary artery disease (> 50% diameter stenosis) was present in 37 patients. During peak dobutamine stress, wall motion asynergy developed or worsened in 30 patients, yielding an overall sensitivity for detection of coronary artery disease of 81% and a specificity of 100%. Corresponding data were 51% and 63% for dobutamine electrocardiography and 70% and 63% for exercise electrocardiography. The sensitivity of dobutamine MRI for the detection of coronary artery disease in patients with single-, double- and triple-vessel disease was 75% (15 of 20 patients), 80% (8 of 10) and 100% (7 of 7), respectively. Dobutamine MRI is an accurate nonexercise-dependent method for the assessment of myocardial ischemia in patients with coronary artery disease.

Comparison between qualitative and quantitative wall motion analyses using dipyridamole stress breath-hold cine magnetic resonance imaging in patients with severe coronary artery stenosis

Article

Dec 1997
MAGN RESON IMAGING

Breath-hold cine magnetic resonance imaging (MRI) at rest and during dipyridamole infusion was used to study wall motion abnormalities in patients with severe coronary artery stenosis proven by coronary angiography. Sixteen patients without myocardial infarction but at least one major coronary artery with > or = 70% diameter narrowing were included. Qualitative "visual" assessment of wall motion, as well as quantitative measurement "wall thickening changes (%)" were compared using receiver operating characteristic curve analysis. 201Tl-single-photon emission computed tomography (SPECT) was also studied for comparison. Using qualitative analysis, coronary artery disease detection rate was comparable when assessing wall motion abnormalities with dipyridamole-MRI (79%) and with dipyridamole-induced perfusion defects with 201-thallium-SPECT (75%). Furthermore, sensitivity and specificity for identification of all diseased coronary territories were comparable for both imaging modalities (sensitivity of dipyridamole-MRI and 201thallium-SPECT, 80% vs. 69%; specificity, 75% vs. 80%). The quantitative method has a substantially higher sensitivity than the qualitative method in identifying all diseased territories (Az = 0.81, p < 0.01 vs. Az = 0.55 and 0.59). In addition, we demonstrated that the quantitative method had higher performance than the qualitative one in identifying the diseased vessels territories related to 1-vessel, 2-vessel, and each of individual coronary artery stenoses.

Noninvasive Diagnosis of Ischemia-Induced Wall Motion Abnormalities With the Use of High-Dose Dobutamine Stress MRI Comparison With Dobutamine Stress Echocardiography

Article

Feb 1999

The analysis of wall motion abnormalities with dobutamine stress echocardiography (DSE) is an established method for the detection of myocardial ischemia. With ultrafast magnetic resonance tomography, identical stress protocols as used for echocardiography can be applied. In 208 consecutive patients (147 men, 61 women) with suspected coronary artery disease, DSE with harmonic imaging and dobutamine stress magnetic resonance (DSMR) (1.5 T) were performed before cardiac catheterization. DSMR images were acquired during short breath-holds in 3 short-axis views and a 4- and a 2-chamber view (gradient echo technique). Patients were examined at rest and during a standard dobutamine-atropine scheme until submaximal heart rate was reached. Regional wall motion was assessed in a 16-segment model. Significant coronary heart disease was defined as >/=50% diameter stenosis. Eighteen patients could not be examined by DSMR (claustrophobia 11 and adipositas 6) and 18 patients by DSE (poor image quality). Four patients did not reach target heart rate. In 107 patients, coronary artery disease was found. With DSMR, sensitivity was increased from 74.3% to 86.2% and specificity from 69.8% to 85.7% (both P<0.05) compared with DSE. Analysis for women yielded similar results. High-dose dobutamine magnetic resonance tomography can be performed with a standard dobutamine/atropine stress protocol. Detection of wall motion abnormalities by DSMR yields a significantly higher diagnostic accuracy in comparison to DSE.

Utility of Fast Cine Magnetic Resonance Imaging and Display for the Detection of Myocardial Ischemia in Patients Not Well Suited for Second Harmonic Stress Echocardiography

Article

Nov 1999
CIRCULATION

Some patients referred for pharmacological stress testing with transthoracic echocardiography (TTE) are unable to undergo testing owing to poor acoustic windows. Fast cine MRI can be used to assess left ventricular contraction, but its utility for detection of myocardial ischemia in patients poorly suited for echocardiography is unknown. One hundred fifty-three patients (86 men and 67 women aged 30 to 88 years) with poor acoustic windows that prevented adequate second harmonic TTE imaging were consecutively referred for MRI to diagnose inducible myocardial ischemia during intravenous dobutamine and atropine. Diagnostic studies were completed in an average of 53 minutes. No patients experienced myocardial infarction, ventricular fibrillation, exacerbation of congestive heart failure, or death. In patients who underwent computer-assisted quantitative coronary angiography, the sensitivity and specificity for detecting a >50% luminal diameter narrowing were 83% and 83%, respectively. In the 103 patients with a negative MRI examination, the cardiovascular occurrence-free survival rate was 97%. Fast cine cardiac MRI provides a mechanism to assess left ventricular contraction and diagnose inducible myocardial ischemia in patients not well suited for stress echocardiography.

Noninvasive Detection of Myocardial Ischemia From Perfusion Reserve Based on Cardiovascular Magnetic Resonance

Article

Mar 2000
CIRCULATION

Myocardial perfusion reserve can be noninvasively assessed with cardiovascular MR. In this study, the diagnostic accuracy of this technique for the detection of significant coronary artery stenosis was evaluated. In 15 patients with single-vessel coronary artery disease and 5 patients without significant coronary artery disease, the signal intensity-time curves of the first pass of a gadolinium-DTPA bolus injected through a central vein catheter were evaluated before and after dipyridamole infusion to validate the technique. A linear fit was used to determine the upslope, and a cutoff value for the differentiation between the myocardium supplied by stenotic and nonstenotic coronary arteries was defined. The diagnostic accuracy was then examined prospectively in 34 patients with coronary artery disease and was compared with coronary angiography. A significant difference in myocardial perfusion reserve between ischemic and normal myocardial segments (1.08+/-0.23 and 2.33+/-0.41; P<0.001) was found that resulted in a cutoff value of 1.5 (mean minus 2 SD of normal segments). In the prospective analysis, sensitivity, specificity, and diagnostic accuracy for the detection of coronary artery stenosis (> or =75%) were 90%, 83%, and 87%, respectively. Interobserver and intraobserver variabilities for the linear fit were low (r=0.96 and 0.99). MR first-pass perfusion measurements yielded a high diagnostic accuracy for the detection of coronary artery disease. Myocardial perfusion reserve can be easily and reproducibly determined by a linear fit of the upslope of the signal intensity-time curves.

Assessment of Myocardial Perfusion in Coronary Artery Disease by Magnetic Resonance: A Comparison With Positron Emission Tomography and Coronary Angiography

Article

May 2001
CIRCULATION

Monitoring contrast medium wash-in kinetics in hyperemic myocardium by magnetic resonance (MR) allows for the detection of stenosed coronary arteries. In this prospective study, the quality of a multislice MR approach with respect to the detection and sizing of compromised myocardium was determined and compared with positron emission tomography (PET) and quantitative coronary angiography. A total of 48 patients and healthy subjects were studied by MR using a multislice hybrid echo-planar pulse sequence for monitoring the myocardial first pass kinetics of gadolinium-diethylenetriamine pentaacetic acid bismethylamide (Omniscan; 0.1 mmol/kg injected at 3 mL/s IV) during hyperemia (dipyridamole 0.56 mg/kg). Signal intensity upslope as a measure of myocardial perfusion was calculated in 32 sectors per heart from pixelwise parametric maps in the subendocardial layer and for full wall thickness. Before coronary angiography, coronary flow reserve (hyperemia induced by dipyridamole 0.56 mg/kg) was determined in corresponding sectors by (13)N-ammonia PET. Receiver-operator characteristic analysis of subendocardial upslope data revealed a sensitivity and specificity of 91% and 94%, respectively, for the detection of coronary artery disease as defined by PET (mean coronary flow reserve minus 2SD of controls) and a sensitivity and specificity of 87% and 85%, respectively, in comparison with quantitative coronary angiography (diameter stenosis >/=50%). The number of pathological sectors per patient on PET and MR studies correlated linearly (slope, 0.94; r=0.76; P<0.0001). The presented MR approach reliably identifies patients with coronary artery stenoses and provides information on the amount of compromised myocardium, even when perfusion abnormalities are confined to the subendocardial layer. This modality may qualify for its clinical application in the management of coronary artery disease.

Assessment of coronary flow reserve: Comparison between contrast-enhanced magnetic resonance imaging and positron emission tomography

Article

Apr 2002
J AM COLL CARDIOL

The study compared flow reserve indices by magnetic resonance imaging (MRI) with quantitative measures of coronary angiography and positron emission tomography (PET). The noninvasive evaluation of myocardial flow by MRI has recently been introduced. However, a comparison to quantitative flow measurement as assessed by PET has not been reported in patients with coronary artery disease (CAD). Two groups of healthy volunteers and 25 patients with angiographically documented CAD were examined by MRI and PET at rest and during adenosine stress. Dynamic MRI was performed using a multi-slice ultra-fast hybrid sequence and a rapid gadolinium-diethylenetriaminepenta-acetic acid bolus injection (0.05 mmol/l). Upslope and peak-intensity indices were regionally determined from first-pass signal intensity curves and compared to N-13 ammonia PET flow reserve measurements. In healthy volunteers, the upslope analysis showed a stress/rest index of 2.1 plus minus 0.6, which was higher than peak intensity (1.5 plus minus 0.3), but lower than flow reserve by PET (3.9 plus minus 1.1). Localization of coronary artery stenoses (> 75%, MRI < 1.2), based on the upslope index, yielded sensitivity, specificity and diagnostic accuracy of 69%, 89% and 79%, respectively. Upslope index correlated with PET flow reserve (r = 0.70). A reduced coronary flow reserve (PET < 2.0, MRI < 1.3) was detected by the upslope index with sensitivity, specificity and diagnostic accuracy of 86%, 84% and 85%, respectively. Magnetic resonance imaging first-pass perfusion measurements underestimate flow reserve values, but may represent a promising semi-quantitative technique for detection and severity assessment of regional CAD.

Magnetic resonance perfusion imaging in patients with coronary artery disease: A qualitative approach

Article

Nov 2002

Although contrast-enhanced first pass magnetic resonance imaging (MRI) has potential to quantify blood flow through extensive image post-processing, clinical utility is likely to depend on rapid qualitative analysis. To investigate use of an on-line analytical approach for detection of coronary artery disease (CAD). Thirty subjects with CAD underwent contrast-enhanced rest/adenosine stress MRI with basal, mid-papillary and apical short-axis image acquisition. Each short axis was divided into eight regions of interest (ROI). Regional perfusion was visually classified as normal or impaired according to transmural distribution and defect reversibility. MRI and angiographic data were compared. Qualitative MRI reporting was possible for 98% ROI. Eighty-six coronary artery (CA) territories were assessed of which 71 (83%) had stenoses. Sensitivity and specificity for detection of stenoses were 93 and 60%, respectively. The proportion of hypoperfused ROI rose from 31% with < 50% stenosis to 65% with occlusion. More transmural defects were seen in infarction-related territories (75 vs. 54%, p < 0.05). More ROI demonstrated defect reversibility in occluded rather than in stenosed infarction-related vessels (89 vs. 58%, p < 0.05). Occluded vessels with grade 2-3 collaterals contained a higher proportion of normal ROI (44 vs. 25%, p < 0.05). Qualitative MRI analysis had high sensitivity and moderate specificity for detecting CA stenoses. Additional information was obtained relating to lesion severity, previous infarction, myocardial viability and impact of collateral circulation. The technique has potential for de novo diagnosis of CAD and as a complementary modality to angiography to assess the significance of given angiographic lesions.

Combined First-Pass Perfusion and Viability Study at MR Imaging in Patients with Non–ST Segment-Elevation Acute Coronary Syndromes: Feasibility Study1

Article

Apr 2003

To assess the feasibility of combined perfusion and viability testing by using magnetic resonance (MR) imaging in one setting in patients with non-ST segment-elevation acute coronary syndromes. The data of 13 patients (mean age, 68 years; range, 40-85 years) at high risk for myocardial infarction who underwent MR imaging at 1.5 T were reviewed. Risk factors were increased troponin T levels in seven, reversible ST depression on an electrocardiogram in four, history of myocardial infarction in two, and presence of heart failure in four. Cine imaging of the left ventricle was performed with a true-fast imaging with steady-state precession (FISP) sequence to assess the regional myocardial contraction and ejection fraction. After injection of 0.1 mmol per kilogram of body weight of gadopentetate dimeglumine, first-pass MR images were obtained by using an inversion-recovery true-FISP sequence at rest and during infusion of adenosine (140 microg/kg/min). Resting and stress images were assessed qualitatively for abnormal regional perfusion (hypoenhancement). The myocardium was divided into three radial segments corresponding to the three coronary artery territories. Delayed (after 15 minutes) contrast material-enhanced images were acquired with use of a segmented inversion-recovery fast low-angle shot sequence. Conventional coronary angiograms were compared with the first-pass images. A more than 50% stenosis in diameter in any coronary artery was considered substantial. Mann-Whitney test was used to assess any significant difference between the left ventricular ejection fraction (LVEF) in patients with and those without myocardial infarct. Mean LVEF was 51.5% (range, 30%-77%). First-pass stress perfusion studies depicted 25 segments of hypoenhancement in 11 patients. Comparison of first-pass perfusion defects with findings on coronary angiograms indicated an overall sensitivity of 92% (24 of 26) and specificity of 92% (12 of 13) in detection of substantial coronary artery disease. Infarcts detected from hyperenhancement on delayed contrast-enhanced images were present in eight segments (four were transmural) in five patients. No significant difference was noted in the LVEF between patients with and those without infarct (P =.724). Combined stress perfusion and viability MR imaging was feasible in patients with acute coronary syndromes. First-pass MR perfusion defects compare well with the presence of substantial coronary artery stenosis on conventional angiograms.

Feasibility to detect severe coronary artery stenoses with upright treadmill exercise magnetic resonance imaging

Article

Sep 2003
AM J CARDIOL

We performed treadmill exercise magnetic resonance imaging in 27 patients with exertional chest pain who were referred for contrast coronary angiography to determine the feasibility of this method to identify severe coronary artery stenoses. The sensitivity and specificity for detecting >70% coronary artery luminal diameter narrowings on contrast coronary angiography were 79% and 85%, respectively.

Noninfarcted Myocardium: Correlation between Dynamic First-Pass Contrast-enhanced Myocardial MR Imaging and Quantitative Coronary Angiography1

Article

Oct 2003

To determine the accuracy of first-pass contrast material-enhanced stress myocardial magnetic resonance (MR) imaging for depiction of myocardial ischemia in patients without myocardial infarction. First-pass contrast-enhanced MR images of the entire left ventricle were acquired in 104 patients at rest and during dipyridamole-induced stress by using an interleaved notched saturation technique. Coronary angiography was performed in all patients, and stress perfusion single photon emission computed tomography (SPECT) was performed in 69 patients. Receiver operating characteristic curve analysis was performed to compare the diagnostic accuracies of first-pass contrast-enhanced stress MR imaging and stress SPECT, with coronary angiography as the reference standard. The overall sensitivity of MR imaging for depicting at least one coronary artery with significant stenosis was 90% (69 of 77 patients). The sensitivities of MR imaging for depiction of single-, double-, and triple-vessel stenoses were 85% (33 of 39 patients), 96% (22 of 23 patients), and 100% (15 of 15 patients), respectively. The specificity of MR imaging for identification of patients with significant coronary artery stenoses was 85% (23 of 27 patients). The areas under the receiver operating characteristic curve for detection of significant stenosis in individual coronary arteries were 0.888 (observer 1) and 0.911 (observer 2) for MR imaging and 0.707 (observer 1, P <.001) and 0.750 (observer 2, P <.001) for SPECT. In patients without myocardial infarction, stress enhancement at dynamic MR imaging correlates more closely with quantitative coronary angiography results than does stress enhancement at SPECT.

Whole-Heart Dipyridamole Stress First-Pass Myocardial Perfusion MRI for the Detection of Coronary Artery Disease

Article

Jun 2004

A whole-heart coverage MRI sequence, which employes a hybrid of fast gradient echo and echo planar acquisition imaging (FastCard EchoTrain), has recently been developed. Using this sequence, a first-pass myocardial perfusion MRI was shown to be a good noninvasive modality for detecting coronary artery disease (CAD) in a clinical setting. In addition, the clinical usefulness of delayed enhanced MRI has recently been reported. The objectives of this study were (1) to investigate the accuracy of dipyridamole stress first-pass myocardial perfusion MRI for diagnosing CAD (> 50% stenosis) and (2) to clarify whether additional delayed enhancement MRI has any clinical significance. We performed first-pass myocardial perfusion MRI in 102 consecutive patients (66 +/- 9 years old) suspected to have CAD or new lesions in patients with well-documented prior myocardial infarction (MI). Using a 1.5 T cardiac MR imager (GE CV/i), eight short axis MR images of the left ventricle were acquired by injecting gadolinium (0.1 mmol/kg) under dipyridamole infusion stress (0.56 mg/kg). Fifteen minutes later, aminophylline (250 mg) was injected and first-pass perfusion MRI was repeated in the resting state in order to evaluate both the presence of perfusion defect and delayed enhancement. The presence of perfusion defect and delayed enhancement was determined based on a visual qualitative analysis by the agreement of two separate readers who were blinded to any clinical information. Based on the stress and rest findings, no defect, reversible defect, or fixed defect with or without delayed enhancement was recorded in any patient. The MR findings revealed 76 CAD patients, including 24 MI patients with new lesions and 26 patients without CAD on coronary angiography. The presence of stress perfusion defect had a 93% sensitivity and an 85% specificity for diagnosing CAD. A fixed defect showed an 86% sensitivity and a 66% specificity for diagnosing a prior MI. Patients with a fixed defect with delayed enhancement had more significant stenosis in the infarct related artery than in those without any enhancement (11/26 vs 15/20, P < 0.05). Dipyridamole stress first-pass myocardial perfusion MRI using the FastCard EchoTrain was found to be a clinically useful and accurate modality for diagnosing CAD.

Comparison of dobutamine stress magnetic resonance, adenosine stress magnetic resonance and adenosine stress perfusion

Article

Sep 2004
CIRCULATION

Dobutamine stress MR (DSMR) is highly accurate for the detection of inducible wall motion abnormalities (IWMAs). Adenosine has a more favorable safety profile and is well established for the assessment of myocardial perfusion. We evaluated the diagnostic value of IWMAs during dobutamine and adenosine stress MR and adenosine MR perfusion compared with invasive coronary angiography. Seventy-nine consecutive patients (suspected or known coronary disease, no history of prior myocardial infarction) scheduled for cardiac catheterization underwent cardiac MR (1.5 T). After 4 minutes of adenosine infusion (140 microg x kg(-1) x min(-1) for 6 minutes), wall motion was assessed (steady-state free precession), and subsequently perfusion scans (3-slice turbo field echo-echo planar imaging; 0.05 mmol/kg Gd-BOPTA) were performed. After a 15-minute break, rest perfusion was imaged, followed by standard DSMR/atropine stress MR. Wall motion was classified as pathological if > or =1 segment showed IWMAs. The transmural extent of inducible perfusion deficits (<25%, 25% to 50%, 51% to 75%, and >75%) was used to grade segmental perfusion. Quantitative coronary angiography was performed with significant stenosis defined as >50% diameter stenosis. Fifty-three patients (67%) had coronary artery stenoses >50%; sensitivity and specificity for detection by dobutamine and adenosine stress and adenosine perfusion were 89% and 80%, 40% and 96%, and 91% and 62%, respectively. Adenosine IWMAs were seen only in segments with >75% transmural perfusion deficit. DSMR is superior to adenosine stress for the induction of IWMAs in patients with significant coronary artery disease. Visual assessment of adenosine stress perfusion is sensitive with a low specificity, whereas adenosine stress MR wall motion is highly specific because it identifies only patients with high-grade perfusion deficits. Thus, DSMR is the method of choice for current state-of-the-art treatment regimens to detect ischemia in patients with suspected or known coronary artery disease but no history of prior myocardial infarction.

Detection of coronary artery disease by magnetic resonance myocardial perfusion imaging with various contrast medium doses: First european multi-centre experience

Article

Sep 2004

Magnetic resonance (MR) first-pass myocardial perfusion imaging during hyperaemia detects coronary artery stenoses in humans with test sensitivity depending on contrast medium (CM)-induced signal change in myocardium. In this prospective multi-centre study, the effect of CM dose on myocardial signal change and on diagnostic performance was evaluated using a stress-only approach. Ninety-four patients with known or suspected coronary artery disease (CAD) were randomised to 0.05,0.10, or 0.15 mmol/kg body weight of an extravascular CM (Gd-DTPA) and X-ray coronary angiography was performed within 30 days prior/after the MR examination. A multi-slice MR technique with identical hardware and software in all centres was used during hyperaemia (adenosine 0.14 mg/kg/min) to monitor myocardial CM wash-in kinetics and data were analysed semi-automatically in a core laboratory. Protocol violations resulted in 80 complete studies with CAD (defined as > or =1 vessel with diameter stenosis > or =50% on quantitative coronary angiography) present in 19/29, 13/24, and 20/27 patients for doses 1, 2, and 3, respectively. In normal myocardium, the upslope increased with CM dose (overall-p<0.0001, ANOVA). For CAD detection the area under the receiver operator characteristics curve for subendocardial data (3 slices with quality score<4 representing 86% of cases) was 0.91+/-0.07 and 0.86+/-0.08 for doses 2 and 3, respectively, and was lower for dose 1 (0.53+/-0.13, p<0.01 and p<0.02 vs. doses 2 and 3, respectively). Corresponding sensitivities/specificities (95% confidence intervals) for pooled doses 2/3 were 93% (77-99%; ns vs. dose 1) and 75% (48-92%;p<0.05 vs. dose 1), respectively. With increasing doses of CM, a higher signal response in the myocardium was achieved and consequently this stress-only protocol, with CM doses of 0.10-0.15 mmol/kg combined with a semi-automatic analysis, yielded a high diagnostic performance for the detection of CAD.

Assessment of non-ST-segment elevation acute coronary syndromes with cardiac magnetic resonance imaging

Article

Jan 2005
J AM COLL CARDIOL

The goal of this study was to determine: 1) if the presence of significant coronary stenosis in patients presenting with non-ST-segment elevation acute coronary syndromes (NSTE-ACS) can be predicted by cardiac magnetic resonance (CMR) imaging; and 2) if the analysis of several CMR methods improves its diagnostic yield compared with analysis of individual methods. With modern acquisition techniques, several CMR methods for the assessment of coronary artery disease (CAD) can be combined in a single noninvasive scanning session. Such a multicomponent CMR examination has not previously been applied to a large patient population, in particular those with a high prevalence of CAD in an acute situation. Sixty-eight patients presenting with NSTE-ACS underwent CMR imaging of myocardial function, perfusion (rest and adenosine-stress), viability (by late contrast enhancement), and coronary artery anatomy. Visual analysis of CMR was carried out. First, all CMR data were reviewed in combination ("comprehensive analysis"). In further separate analyses, each CMR method was analyzed individually. The ability of CMR to detect coronary stenosis >/=70% on X-ray angiography was determined. Comprehensive CMR analysis yielded a sensitivity of 96% and a specificity of 83% to predict the presence of significant coronary stenosis and was more accurate than analysis of any individual CMR method; CMR was significantly more sensitive and accurate than the Thrombolysis In Myocardial Infarction risk score (p < 0.001). Cardiac magnetic resonance imaging accurately predicts the presence of significant CAD in patients with NSTE-ACS. In this study, a comprehensive analysis of several CMR methods improved the accuracy of the test.

Color-Encoded Semiautomatic Analysis of Multi-Slice First-Pass Magnetic Resonance Perfusion: Comparison to Tetrofosmin Single Photon Emission Computed Tomography Perfusion and X-Ray Angiography

Article

Nov 2004

Cardiovascular magnetic resonance (CMR) perfusion can accurately detect coronary artery disease (CAD). However, the absence of efficient, easy-to-use and reliable image analysis software is an obstacle to its introduction into clinical practice. The aim of this study was to evaluate new color-encoded semiautomatic software for analysis of first-pass CMR perfusion in comparison to tetrofosmin myocardial single photon emission computed tomography (SPECT), using X-ray angiography as the standard of truth for the detection of CAD. Thirty-two patients underwent both SPECT and CMR perfusion at rest and adenosine stress. Twenty of these patients also underwent X-ray angiography. Off-line CMR image analysis consisted of six steps to generate a color display of the myocardial perfusion reserve index (MPRI). The MPRI color-maps were analyzed visually and compared to SPECT. In comparison to X-ray angiography overall accuracy was 87% for CMR and 77% for SPECT perfusion to detect significant CAD (stenosis > or =70%). In comparison with SPECT sensitivity was 80%, specificity 91%, and the overall agreement 89% for CMR. Post-processing of CMR perfusion data using new semiautomatic software to generate and display the MPRI visually as color-encoded images is feasible and fast. In this study it yielded higher accuracy than SPECT to detect significant CAD on X-ray angiography. Correlation between SPECT and CMR accuracy for detection of perfusion defects was high. This method may accelerate the time-consuming analysis of CMR perfusion data, thus enabling a more widespread clinical utility.

Assessment of coronary artery disease with nicorandil stress magnetic resonance imaging

Article

Jan 2005
Osaka City Med J

Although dipyridamole and adenosine have been used as vasodilator agents, we believe they are inadequate for vasodilator perfusion magnetic resonance imaging, due to adverse effects (flushing, warmth, headaches, and arrhythmia). Nicorandil, a potassium channel opener, has been reported to increase coronary blood flow and it was associated with fewer adverse effects than adenosine or dipiridamole. We set out to investigate whether the coronary artery stenosis could be assessed by nicorandil stress perfusion magnetic resonance imaging. First-pass contrast-enhanced magnetic resonance images of the left ventricle acquired from 50 patients at rest and during intravenous administration of nicorandil using multi-slice turbo field echo with multi shot echo-planar-imaging. Coronary angiography was performed within 1 week. There was no adverse effects during nicorandil stress in any patients. The overall sensitivity and specificity of magnetic resonance imaging in identifying patients with significant stenosis of at least one coronary artery were 93.9% (31 of 33 patients) and 94.1% (16 of 17 patients), respectively. The sensitivity of magnetic resonance imaging for detecting significant stenosis in the left anterior descending artery was 87.5%; the sensitivity in the left circumflex artery was 80%; the sensitivity in the right coronary artery was 92.3%. Similar sensitivities were observed for all 3 vascular regions, indicating that all myocardial segments were visualized with similar image quality. The present study shows that nicorandil stress perfusion magnetic resonance imaging is a safe, feasible technique for assessing coronary artery stenosis severity in a totally-noninvasive manner.

Coronary Artery Disease: Myocardial Perfusion MR Imaging with Sensitivity Encoding versus Conventional Angiography1

Article

Jun 2005

To evaluate the technical performance of sensitivity encoding (SENSE)-accelerated myocardial perfusion magnetic resonance (MR) imaging and prospectively assess the diagnostic accuracy of this examination for depiction of significant coronary artery disease (CAD). All 102 subjects provided written informed consent, and the local ethics committee approved the study. A saturation-recovery segmented k-space gradient-echo pulse sequence was combined with SENSE to allow dynamic acquisition of myocardial perfusion data on four parallel short-axis MR image sections at every heartbeat. This technique was evaluated in 10 healthy volunteers and in 92 patients scheduled to undergo conventional coronary angiography. Gadopentetate dimeglumine was peripherally injected at rest and during adenosine-induced stress. The maximal upslope of the signal intensity-time profiles was plotted for 16 myocardial segments defined on three MR image sections, and a myocardial perfusion reserve index (MPRI) between stress and rest, normalized to the input function from the blood pool of the most basal section, was calculated. Areas under receiver operating characteristic curves (AUCs) were used to assess the diagnostic performance of cardiac MR imaging for depiction of greater than 70% CAD seen at coronary angiography, the reference standard. In volunteers, the mean myocardial enhancement was 2.1 +/- 1.2 (standard deviation), with homogeneous signal intensity distribution across the segments. The diagnostic accuracy of MPRI measurements was high (AUC, 0.908; sensitivity, 88% [52 of 59 patients]; specificity, 82% [27 of 33 patients]). Diagnostic performance was similar among separate analyses of the three coronary territories and among separate analyses of data in the patients with diabetes mellitus, left ventricular hypertrophy, or myocardial infarction. Multisection myocardial perfusion MR imaging with SENSE is feasible and has high diagnostic accuracy in the detection of CAD.

Diagnostic Accuracy of Stress First-Pass Contrast-Enhanced Myocardial Perfusion MRI Compared with Stress Myocardial Perfusion Scintigraphy

Article

Aug 2005

The purpose of this study was to determine the diagnostic accuracy of stress perfusion MRI acquired with saturation-recovery prepared turbo fast low-angle shot (turbo FLASH) compared with stress myocardial perfusion scintigraphy. Recent studies show that first-pass contrast-enhanced myocardial perfusion MRI can provide noninvasive detection of low-limiting stenosis in the coronary artery. First-pass contrast-enhanced MR images were acquired at rest and during stress in 40 patients with suspected coronary artery disease. All patients underwent thallium-201 SPECT without attenuation correction and coronary angiography. Two reviewers independently assigned one of five confidence grades without knowing the results of coronary angiography for receiver operating characteristic (ROC) analysis. Luminal stenosis >70% on coronary angiography was used as a reference standard. On coronary angiography, 70% or greater diameter stenosis of the coronary artery was observed in 21 (52.5%) of 40 patients. The areas under the ROC curve for detection of significant stenosis in the individual coronary artery were 0.86 (observer 1) and 0.84 (observer 2) for MRI. These values were 0.79 (observer 1, p = not significant) and 0.72 (observer 2, p = not significant) for 201Tl SPECT. The diagnostic accuracy of stress perfusion MRI acquired with saturation-recovery-prepared turbo FLASH was comparable with that of stress 201Tl SPECT. Stress first-pass contrast-enhanced MRI is a noninvasive technique that can be used as an alternative to stress myocardial perfusion scintigraphy.

Evaluation of ischemic heart disease on a 1.5 tesla scanner: Combined first-pass perfusion and viability study

Article

Jul 2005

We implemented a fast gradient echo (GRE) sequence with an echo-planar imaging (EPI) read-out (FGRE-ET) to conduct myocardial perfusion studies on a conventional scanner. The accuracy of combined perfusion and viability studies is evaluated in comparison with coronary angiography (CAG). We enrolled 33 patients suspected of having coronary artery disease in this study. Short-axis perfusion images of the left ventricles were acquired following intravenous bolus injection of gadolinium-DTPA (0.05 mml/kg), both after myocardial loading by dipyridamole (0.56 mg/kg) and at rest. Viability studies were obtained using an inversion-recovery FGRE sequence. Radiologists performed blinded film readings. The findings with perfusion and the viability studies were compared with CAG on a segment-to-segment basis corresponding to the coronary arteries' territories. Stenosis equal to or greater than 75% in diameter was considered significant on CAG. The results were also compared with single photon emission computed tomography (SPECT) in 23 patients. The combination of perfusion and viability studies showed 85.7% sensitivity, 88.9% specificity, and 87.2% accuracy in comparison with CAG. SPECT revealed respective rates of 71.7%, 78.3%, and 73.9% in 23 patients of this group. Myocardial perfusion studies using FGRE-ET were feasible and accurate, even on a conventional scanner.

Reitsma JB, Glas AS, Rutjes AWS, Scholten RJPM, Bossuyt PM, Zwinderman AH. Bivariate analysis of sensitivity and specificity produces informative summary measures in diagnostic reviews. J Clin Epidemiol 58: 982-990

Article

Nov 2005
J CLIN EPIDEMIOL

Studies of diagnostic accuracy most often report pairs of sensitivity and specificity. We demonstrate the advantage of using bivariate meta-regression models to analyze such data. We discuss the methodology of both the summary Receiver Operating Characteristic (sROC) and the bivariate approach by reanalyzing the data of a published meta-analysis. The sROC approach is the standard method for meta-analyzing diagnostic studies reporting pairs of sensitivity and specificity. This method uses the diagnostic odds ratio as the main outcome measure, which removes the effect of a possible threshold but at the same time loses relevant clinical information about test performance. The bivariate approach preserves the two-dimensional nature of the original data. Pairs of sensitivity and specificity are jointly analyzed, incorporating any correlation that might exist between these two measures using a random effects approach. Explanatory variables can be added to the bivariate model and lead to separate effects on sensitivity and specificity, rather than a net effect on the odds ratio scale as in the sROC approach. The statistical properties of the bivariate model are sound and flexible. The bivariate model can be seen as an improvement and extension of the traditional sROC approach.

Prognosis of Negative Adenosine Stress Magnetic Resonance in Patients Presenting to an Emergency Department With Chest Pain

Article

May 2006

This study was designed to determine the diagnostic value of adenosine cardiac magnetic resonance (CMR) in troponin-negative patients with chest pain. We hypothesized that adenosine CMR could determine which troponin-negative patients with chest pain in an emergency department have coronary artery disease (CAD) or future adverse cardiac events. Adenosine stress CMR was performed on 135 patients who presented to the emergency department with chest pain and had acute myocardial infarction (MI) excluded by troponin-I. The main study outcome was detecting any evidence of significant CAD. Patients were contacted at one year to determine the incidence of significant CAD defined as coronary artery stenosis >50% on angiography, abnormal correlative stress test, new MI, or death. Adenosine perfusion abnormalities had 100% sensitivity and 93% specificity as the single most accurate component of the CMR examination. Both cardiac risk factors and CMR were significant in Kaplan-Meier analysis (log-rank test, p = 0.0006 and p < 0.0001, respectively). However, an abnormal CMR added significant prognostic value in predicting future diagnosis of CAD, MI, or death over clinical risk factors. In receiver operator curve analysis, adenosine CMR was a more accurate predictor than cardiac risk factors (p < 0.002). In patients with chest pain who had MI excluded by troponin-I and non-diagnostic electrocardiograms, an adenosine CMR examination predicted with high sensitivity and specificity which patients had significant CAD during one-year follow-up. Furthermore, no patients with a normal adenosine CMR study had a subsequent diagnosis of CAD or an adverse outcome.

Improved Detection of Coronary Artery Disease by Stress Perfusion Cardiovascular Magnetic Resonance With the Use of Delayed Enhancement Infarction Imaging

Article

Apr 2006

We tested a pre-defined visual interpretation algorithm that combines cardiovascular magnetic resonance (CMR) data from perfusion and infarction imaging for the diagnosis of coronary artery disease (CAD). Cardiovascular magnetic resonance can assess both myocardial perfusion and infarction with independent techniques in a single session. We prospectively enrolled 100 consecutive patients with suspected CAD scheduled for X-ray coronary angiography. Patients had comprehensive clinical evaluation, including Rose angina questionnaire, 12-lead electrocardiography, C-reactive protein, and calculation of Framingham risk. Cardiovascular magnetic resonance included cine, adenosine-stress and rest perfusion-CMR, and delayed enhancement-CMR (DE-CMR) for infarction imaging. Matched stress-rest perfusion defects in the absence of infarction by DE-CMR were considered artifactual. All patients underwent X-ray angiography within 24 h of CMR. Ninety-two patients had complete CMR examinations. Significant CAD (> or =70% stenosis) was found in 37 patients (40%). The combination of perfusion and DE-CMR had a sensitivity, specificity, and accuracy of 89%, 87%, and 88%, respectively, for CAD diagnosis, compared with 84%, 58%, and 68%, respectively, for perfusion-CMR alone. The combination had higher specificity and accuracy (p < 0.0001), owing to incorporating the exceptionally high specificity (98%) of DE-CMR. Receiver operating characteristic curve analysis demonstrated the combination provided better performance than cine, perfusion, or DE-CMR alone. The accuracy was high in single-vessel and multivessel disease and independent of CAD location. Multivariable analysis including standard clinical parameters demonstrated the combination was the strongest independent CAD predictor. A combined perfusion and infarction CMR examination with a visual interpretation algorithm can accurately diagnose CAD in the clinical setting. The combination is superior to perfusion-CMR alone.

Cardiac magnetic resonance perfusion imaging for the functional assessment of coronary artery disease: A comparison with coronary angiography and fractional flow reserve

Article

Jun 2006

Diagnostic Performance of Stress Perfusion and Delayed-Enhancement MR Imaging in Patients with Coronary Artery Disease 1

Article

Aug 2006

To prospectively determine the accuracy of a combined magnetic resonance (MR) imaging approach (stress first-pass perfusion imaging followed by delayed-enhancement imaging) for depicting clinically significant coronary artery stenosis (> or = 70% stenosis) in patients suspected of having or known to have coronary artery disease (CAD), with coronary angiography serving as the reference standard. The committee on human research approved the study protocol, and all participants gave written informed consent. This study was HIPAA compliant. Forty-seven patients (38 men and nine women; mean age, 63 years +/- 5.3 [standard deviation]) scheduled for coronary angiography were prospectively enrolled: 33 were suspected of having CAD (group A) and 14 had experienced a previous myocardial infarction and were suspected of having new lesions (group B). The MR imaging protocol included cine function, gadolinium-enhanced stress and rest first-pass perfusion MR imaging, and delayed-enhancement MR imaging. Myocardial ischemia was defined as a segment with perfusion deficit at stress first-pass perfusion MR imaging and no hyperenhancement at delayed-enhancement imaging. Myocardial infarction was defined as an area with hyperenhancement at delayed-enhancement imaging. One patient was excluded from analysis because of poor-quality MR images. Coronary angiography depicted significant stenosis in 30 of 46 patients (65%). In a per-vessel analysis (n = 138), stress first-pass perfusion MR imaging and delayed-enhancement imaging yielded sensitivity of 0.87, specificity of 0.89, and accuracy of 0.88, when compared with coronary angiography. The diagnostic accuracy of stress first-pass perfusion MR imaging and delayed-enhancement imaging was slightly better than that of stress and rest first-pass perfusion MR imaging in the entire population (0.88 vs 0.85), in group A (0.86 vs 0.82), and in group B (0.93 vs 0.90). Stress first-pass perfusion MR imaging followed by delayed-enhancement imaging is an accurate method to depict significant coronary stenosis in patients suspected of having or known to have CAD.

Clinical implication of adenosine-stress cardiac magnetic resonance imaging as potential gatekeeper to invasive examination in patients with AHA/ACC class II indication for coronary angiography

Article

Oct 2006

Real world cardiology is faced with a low diagnostic yield of coronary angiography (CXA) in patients presenting with ACC/AHA class II CXA indication. Our aim was to analyze the clinical implication of a Cardiac MR (CMR) protocol including adenosine stress perfusion in this patient population. We examined whether CMR could enhance appropriate CXA indication and thus reduce the rate of pure diagnostic CXA. In addition, we compared the relative impact of CMR exam components (perfusion, function and viability assessment) in achieving this target. 176 patients were referred for CXA with class II indication. 171 underwent complete additional CMR exam in a 1.5-T whole body CMR-scanner for myocardial function, ischemia and viability prior to CXA. The routine protocol for assessment of CAD consisted of functional imaging (long and short axes), adenosine stress- and rest-perfusion in short axis orientation and "late enhancement" imaging in long and short axes. Images were analyzed by two independent and blinded investigators. Interobserver differences were resolved by a third reader. There was a high association between CMR results and subsequent invasive findings (chi square for CMR perfusion deficit and stenosis >70% in CXA: 113.7, p<0.0001). 109 (63.7%) of our patients had relevant perfusion deficits as seen by CMR and matching coronary artery stenosis >70%. Four (2.3%) patients had false negative CMR findings. In 58 patients (33.9%) no relevant coronary artery stenosis could be observed, correctly predicted by CMR in 48 cases; in 10 (5.8%) patients CMR provided false positive results. Sensitivity of CMR to detect relevant CAD (>70% luminal narrowing) was 0.96, specificity 0.83, positive predictive value 0.92 and negative predictive value 0.92. Of the CMR components, perfusion deficit was the strongest independent predictor (odds ratio 132.3, p < 0.0001). In a great number of patients being referred to cath lab with ACC/AHA class II indication for CXA, CMR provides a high accuracy for decision making regarding appropriateness of the invasive exam. CMR prior to CXA could substantially reduce pure diagnostic coronary angiographies in patients with intermediate probability for CAD, in our patient-cohort from approximately 34% to 6%. Further studies are warranted to identify rare false negative CMR results.

Diagnostic Performance of Stress Cardiac Magnetic Resonance Imaging in the Detection of Coronary Artery Disease

Abstract

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