Christian Fink
Publications
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2.65Impact points
Prognostic value of perfusion defect volume at dual energy CTA in patients with pulmonary embolism: Correlation with CTA obstruction scores, CT parameters of right ventricular dysfunction and adverse clinical outcome.
European journal of radiology. 04/2012;
PURPOSE: To investigate the prognostic value of perfusion defect volume (PDvol) at dual-energy-CT-angiography (DE-CTA) in patients with acute pulmonary embolism (PE) by correlating PDvol with CTA-obstruction-scores (OS), CT parameters of right-ventricular-dysfunction (RVD), and adverse-clinical-outc... [more] PURPOSE: To investigate the prognostic value of perfusion defect volume (PDvol) at dual-energy-CT-angiography (DE-CTA) in patients with acute pulmonary embolism (PE) by correlating PDvol with CTA-obstruction-scores (OS), CT parameters of right-ventricular-dysfunction (RVD), and adverse-clinical-outcome. MATERIALS AND METHODS: DE-CTA of 60 patients (mean age: 65±14.4 years) with PE were analyzed. Iodine maps were generated, and normalized PDvol - defined as volume of perfusion defects/total lung volume - was quantified. Furthermore, established prognostic parameters (Qanadli and Mastora-OS, and CT parameters of RVD) were obtained. CT parameters of RVD - namely the right ventricle/left ventricle (RV/LV) diameter ratio measured on transverse sections (RV/LVtrans), four-chamber views (RV/LV4ch), and RV/LV volume ratios (RV/LVvol) - were assessed. PDvol was correlated with OS, CT parameters of RVD and adverse clinical outcome (defined as the need for intensive care treatment or death). RESULTS: 10 of 60 patients with PE experienced adverse clinical outcome. Patients with adverse clinical outcome showed significantly higher PDvol (35±11% vs. 23±10%, p=0.002), RV/LV ratios (RV/LV4ch 1.46±0.32 vs. 1.18±0.26, p=0.005; RV/LVvol 2.25±1.33 vs. 1.19±0.56, p=0.002) and higher Mastora global scores (52 vs. 13, p=0.02) compared to those without adverse clinical outcome. A weak correlation was observed between PDvol and the Mastora global score (r=0.5; p=0.0003), as well as between PDvol and RV/LV4Ch (r=0.432, p=0.0006). No correlation was found between PDvol and the Qanadli score or the remainder of the RVD-CT parameters. CONCLUSION: The extent of perfusion defects as assessed by DE-CTA correlates with adverse clinical outcome in patients with PE. Therefore, volumetric quantification of perfusion defects at DE-CTA allows the identification of low-risk patients who do not require intensified monitoring and treatment.
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2.95Impact points
Aortoiliac CT Angiography for Planning Transcutaneous Aortic Valve Implantation: Aortic Root Anatomy and Frequency of Clinically Significant Incidental Findings.
AJR. American journal of roentgenology. 04/2012; 198(4):939-45.
The purpose of this article is to assess aortic root and iliofemoral vessel anatomy and the frequency of clinically significant incidental findings on aortoiliac CT angiography (CTA) performed for planning of transcutaneous aortic valve implantation. Aortoiliac CTA studies of 207 patients scheduled ... [more] The purpose of this article is to assess aortic root and iliofemoral vessel anatomy and the frequency of clinically significant incidental findings on aortoiliac CT angiography (CTA) performed for planning of transcutaneous aortic valve implantation. Aortoiliac CTA studies of 207 patients scheduled for transcutaneous aortic valve implantation were analyzed. Anatomic dimensions relevant to the interventional procedure, including diameter of the aortic annulus and sinus of Valsalva, distance between aortic annulus and coronary ostia, coronary leaflet length, left ventricular outflow tract diameter, and vessel diameter of iliac arteries, were analyzed. Clinically significant incidental findings were recorded. The mean (± SD) maximum and minimum diameters of the aortic annulus were 29 ± 3.9 mm and 23.5 ± 4.1 mm, respectively. The mean distances between aortic annulus and the ostium of the left and right coronary artery were 13.5 ± 3.2 mm and 14.8 ± 3.9 mm, respectively. The mean maximum and minimum diameters of the left ventricular outflow tract were 27 ± 4 mm and 1.9 ± 4 mm, respectively. The mean diameter of the sinus of Valsalva was 33.4 ± 5.1 mm. The mean diameters of the right and left external iliac artery were 8 ± 1 and 8 ± 2 mm, respectively. Almost half the patients (101/207) had clinically significant incidental findings, including noncalcified pulmonary nodules larger than 8 mm (n = 7), pulmonary embolism (n = 3), or aortic aneurysm (n = 12). Aortoiliac CTA provides relevant information on aortic root and iliofemoral vessel anatomy for preinterventional planning. CTA reveals clinically significant incidental findings in a high number of patients considered for transcutaneous aortic valve implantation, which may have a significant impact on patient selection.
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2.03Impact points
Imaging of Tumor Viability in Lung Cancer: Initial Results Using 23Na-MRI.
RoFo : Fortschritte auf dem Gebiete der Rontgenstrahlen und der Nuklearmedizin. 02/2012; 184(4):340-344.
Purpose: 23Na-MRI has been proposed as a potential imaging biomarker for the assessment of tumor viability and the evaluation of therapy response but has not yet been evaluated in patients with lung cancer. We aimed to assess the feasibility of 23Na-MRI in patients with lung cancer. Materials and Me... [more] Purpose: 23Na-MRI has been proposed as a potential imaging biomarker for the assessment of tumor viability and the evaluation of therapy response but has not yet been evaluated in patients with lung cancer. We aimed to assess the feasibility of 23Na-MRI in patients with lung cancer. Materials and Methods: Three patients with stage IV adenocarcinoma of the lung were examined on a clinical 3 Tesla MRI system (Magnetom TimTrio, Siemens Healthcare, Erlangen, Germany). Feasibility of 23Na-MRI images was proven by comparison and fusion of 23Na-MRI with 1H-MR, CT and FDG-PET-CT images. 23Na signal intensities (SI) of tumor and cerebrospinal fluid (CSF) of the spinal canal were measured and the SI ratio in tumor and CSF was calculated. One chemonaive patient was examined before and after the initiation of combination therapy (Carboplatin, Gemcitabin, Cetuximab). Results: All 23Na-MRI examinations were successfully completed and were of diagnostic quality. Fusion of 23Na-MRI images with 1H-MRI, CT and FDG-PET-CT was feasible in all patients and showed differences in solid and necrotic tumor areas. The mean tumor SI and the tumor/CSF SI ratio were 13.3 ± 1.8 × 103 and 0.83 ± 0.14, respectively. In necrotic tumors, as suggested by central non-FDG-avid areas, the mean tumor SI and the tumor/CSF ratio were 19.4 × 103 and 1.10, respectively. Conclusion: 23Na-MRI is feasible in patients with lung cancer and could provide valuable functional molecular information regarding tumor viability, and potentially treatment response.
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3.54Impact points
CT Angiography of the Aorta Is Superior to Transesophageal Echocardiography for Determining Stroke Subtypes in Patients with Cryptogenic Ischemic Stroke.
Cerebrovascular diseases (Basel, Switzerland). 02/2012; 33(4):322-328.
Background: The etiology of ischemic strokes remains cryptogenic in about one third of patients, even after extensive workup in specialized centers. Atherosclerotic plaques in the aorta can cause thromboembolic events but are often overlooked. They can elude standard identification by transesophagea... [more] Background: The etiology of ischemic strokes remains cryptogenic in about one third of patients, even after extensive workup in specialized centers. Atherosclerotic plaques in the aorta can cause thromboembolic events but are often overlooked. They can elude standard identification by transesophageal echocardiography (TEE), which is invasive or at best uncomfortable for many patients. CT angiography (CTA) can be used as an alternative or in addition to TEE if this technique fails to visualize every part of the aorta and in particular the aortic arch. Methods: We prospectively studied 64 patients (47 men, age 60 ± 13 years) classified as having cryptogenic stroke after standard and full workup [including brain MRI and 24-hour electrocardiogram (ECG)] with ECG-triggered CTA of the aorta in search of plaques and compared the results with those of TEE. Investigators were blinded to the results of both techniques. Plaques were graded on CTA according to their presence (0 = not present; 1 = mild; 2 = severe) and degree of calcification (1a or 2a = noncalcified; 1b or 2b = calcified). Associations with risk factors and infarct localization were also assessed. Results: Only 21 of 64 patients (32.8%) had aortic plaques identified by TEE, compared to 43 of 64 (67.2%) with CTA (p < 0.05). The plaque localization was as follows (TEE vs. CTA): ascending aorta, 10 vs. 20 (p < 0.05); aortic arch, 10 vs. 40 (p < 0.05), and descending aorta, 20 vs. 34 (p < 0.05). Grade 1 plaques were most commonly found in the aortic arch (25; 39%), while grade 2 plaques were most often detected in the aortic arch (15; 23.4%) and the descending aorta (14; 21.9%). There was no significant correlation between plaque location, infarct territory or vascular risk profile, except for hypertension (p = 0.003), which was significantly associated with the presence of plaques. Conclusions: CTA identifies more plaques throughout the aortic arch and around the origins of the major cerebral arteries in particular compared to TEE. These may represent potential embolic sources of acute ischemic stroke. Better plaque detection may have an impact on the best available secondary prevention regimen in individual patients if proximal embolic sources are suspected.
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4.85Impact points
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2.65Impact points
Dual-energy CT angiography of the lungs: comparison of test bolus and bolus tracking techniques for the determination of scan delay.
European journal of radiology. 01/2012; 81(1):132-8.
To prospectively compare test bolus and bolus tracking for the determination of scan delay of pulmonary dual-energy CT angiography in patients with suspected pulmonary embolism. 60 consecutive patients referred for CTA for exclusion of PE were randomized either into a test bolus group or into a bolu... [more] To prospectively compare test bolus and bolus tracking for the determination of scan delay of pulmonary dual-energy CT angiography in patients with suspected pulmonary embolism. 60 consecutive patients referred for CTA for exclusion of PE were randomized either into a test bolus group or into a bolus tracking group. All exams were performed on a 64-channel dual source CT scanner. A standard single-acquisition dual-energy CTA was performed after injection of 100ml Iomeprol 400 followed by a saline chaser of 4 ml/s. The scan delay was determined using either test bolus (n=30) or bolus tracking (n=30). Test bolus was performed using an additional 20 ml Iomeprol 400 injected with a rate of 4 ml/s during acquisition of a series of dynamic low-dose monitoring scans followed by injection of a saline bolus of 20 ml using the same flow rate. For DECT angiography of the lungs 100ml Iomeprol 400 was injected with an injection rate of 4 ml/s followed by a saline chaser of 20 ml using the same flow rate. Attenuation profiles of different vascular segments (pulmonary arteries, pulmonary parenchyma, aorta, all 4 heart chambers) were measured to evaluate the timing techniques. Overall image quality of dual-energy "perfusion" maps and virtual 120 kV CTA images was evaluated by two radiologists regarding the present of artifacts. In all patients an adequate and homogeneous contrast enhancement of more than 400 Hounsfield units (HU) was achieved in the different vascular districts. No statistically significant difference between test bolus and bolus tracking was found regarding vessel attenuation or overall image quality. A homogeneous opacification of the different vascular territories and the pulmonary parenchyma as well as a sufficient image quality can be achieved with either bolus tracking or test bolus techniques.
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2.65Impact points
Attenuation-based characterization of coronary atherosclerotic plaque: comparison of dual source and dual energy CT with single-source CT and histopathology.
European journal of radiology. 10/2011; 80(1):54-9.
To compare different CT acquisition techniques regarding for attenuation-based characterization of coronary atherosclerotic plaques using histopathology as the standard of reference. In a post mortem study 17 human hearts were studied with dual-source CT (DSCT) and dual energy CT (DECT) mode on a DS... [more] To compare different CT acquisition techniques regarding for attenuation-based characterization of coronary atherosclerotic plaques using histopathology as the standard of reference. In a post mortem study 17 human hearts were studied with dual-source CT (DSCT) and dual energy CT (DECT) mode on a DSCT as well as with 16-slice single-source CT (SSCT). At autopsy, atherosclerotic lesions were cut at 5 μm sections. Histopathologic classification of the plaques according to the American Heart Association (AHA) criteria was performed by two pathologists. Attenuation values of all plaques were measured in DSCT, DECT and SSCT studies, respectively and classified based on attenuation according to modified AHA criteria. 58 coronary plaques were identified at autopsy. Regardless of the CT technique only 52/58 plaques were found at CT (sensitivity=89.6%). There was no significant difference between the mean attenuation values of different plaque types between DSCT, DECT, and SSCT: type IV: 11HU/8HU/19HU; type Va: 44HU/45HU/52HU; type Vb: 1088HU/966HU/1079HU). The sensitivity for correct classification varied depending on the plaque type (type II=0%, type III=0%, type IV=43%, type Va=58%, Vb=97%). Independent of the used acquisition technique, SSCT, DSCT and DECT show similar results for attenuation-based characterization of atherosclerotic coronary plaques.
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Coronary computed tomography--present status and future directions.
International journal of clinical practice. Supplement. 10/2011;
The use of coronary computed tomography angiography (cCTA) is growing rapidly, in large part because of fast-paced technical innovations that have increased diagnostic accuracy while providing new opportunities for radiation dose reduction. cCTA using recent generation CT scanners has been repeatedl... [more] The use of coronary computed tomography angiography (cCTA) is growing rapidly, in large part because of fast-paced technical innovations that have increased diagnostic accuracy while providing new opportunities for radiation dose reduction. cCTA using recent generation CT scanners has been repeatedly shown to have excellent negative predictive value for ruling out significant coronary stenosis in comparison with invasive coronary angiography (ICA) and is now accepted for this use in selected populations. Current work is increasingly focused on evaluating and optimising radiation dose reduction techniques, the cost-effectiveness of cCTA implementation, and the impact of cCTA on patient management and outcomes. In addition, the potential value of emerging applications, such as atherosclerotic plaque characterisation and myocardial perfusion and viability assessment, are undergoing intense investigation.
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5.53Impact points
Pulmonary embolism: ct signs and cardiac biomarkers for predicting right ventricular dysfunction.
The European respiratory journal : official journal of the European Society for Clinical Respiratory Physiology. 09/2011;
To prospectively evaluate the accuracy of quantitative cardiac CT parameters and two cardiac biomarkers (NT-pro-Brain Natriuretic Peptide (NT-pro-BNP); troponin I), alone and in combination, for predicting right ventricular dysfunction (RVD) in patients with acute pulmonary embolism (PE).557 consecu... [more] To prospectively evaluate the accuracy of quantitative cardiac CT parameters and two cardiac biomarkers (NT-pro-Brain Natriuretic Peptide (NT-pro-BNP); troponin I), alone and in combination, for predicting right ventricular dysfunction (RVD) in patients with acute pulmonary embolism (PE).557 consecutive patients with suspected PE underwent pulmonary CTA. Patients with PE also underwent echocardiography and NT-pro-BNP/troponin I serum level measurements. 3 different CT measurements were obtained (RV/LVaxial, RV/LV4-CH), and RV/LVvolume). CT measurements and NT-pro-BNP/troponin I serum levels were correlated with RVD at echocardiography.Patients with RVD (n=77) showed significantly higher RV/LV ratios and NT-pro-BNP/troponin I levels compared to those without RVD (RV/LVaxial 1.68±0.84 vs. 1.00±0.21; RV/LV4ch 1.52±0.45 vs. 1.01±0.21; RV/LVvolume 1.97±0.53 vs. 1.07±0.52; serum NT-pro-BNP 6372±2319 vs. 1032±1559 ng·L(-1); troponin I 0.18±0.41 vs. 0.06±0.18). The area under the curve for the detection of RVD of RV/LVaxial, RV/LV4Ch, RV/LVvolume, NT-pro-BNP and troponin I were 0.84, 0.87, 0.93, 0.83 and 0.70 respectively. The combination of biomarkers and RV/LVvolume increased the AUC to 0.95 (RV/LVvolume with NT-pro-BNP) and 0.93 (RV/LVvolume with troponin I).RV/LVvolume is the most accurate CT parameter for identifying patients with RVD. A combination of RV/LVvolume with NT-pro-BNP or troponin I measurements improves the diagnostic accuracy of either test alone.
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4.85Impact points
Contrast-enhanced dual-energy CT of gastrointestinal stromal tumors: is iodine-related attenuation a potential indicator of tumor response?
Investigative radiology. 09/2011; 47(1):65-70.
To assess the correlation of true nonenhanced (TNE) and virtually nonenhanced (VNE) images of abdominal dual-energy computed tomography (DECT) in patients with metastatic gastrointestinal stromal tumors (GIST), and further to investigate the correlation of iodine-related attenuation (IRA) of DECT wi... [more] To assess the correlation of true nonenhanced (TNE) and virtually nonenhanced (VNE) images of abdominal dual-energy computed tomography (DECT) in patients with metastatic gastrointestinal stromal tumors (GIST), and further to investigate the correlation of iodine-related attenuation (IRA) of DECT with the Choi criteria. Twenty-four consecutive patients (5 women aged 61 ± 10 years) with metastatic GIST underwent DECT of the abdomen (80 kV, 140 kV) using first-generation dual-source computed tomography (CT). All patients had at least one or more liver lesions (median, 4; maximum, 9). Image data were processed with a dedicated DECT software algorithm designed for evaluation of iodine distribution in soft tissue lesions, and VNE CT images were generated. The tumor density (according to Choi criteria) and the maximum transverse diameter of the lesions (according to Response Evaluation Criteria in Solid Tumors [RECIST]) were determined. TNE and VNE lesion attenuation and Choi criteria and IRA were correlated with each other. A total of 291 liver lesions were evaluated, of which 220 were cystic and 71 were solid. The mean lesion size was 4.5 ± 3.2 cm (1.1-18.7 cm). The mean attenuation of all lesions was significantly higher in the TNE images than in the VNE images (P=0.0001). Pearson statistics revealed an excellent correlation of r=0.843 (P=0.0001) between IRA and Choi criteria for all lesions. DECT showed significantly higher IRA in progressive (23.3 ± 9.5 HU) lesions compared with stable or regressive (17.8 ± 9.1 HU) lesions (P=0.0185). Similarly, the Choi criteria differed significantly between progressive (39.9 ± 12.8 HU) and stable/regressive (31.1 ± 10.3 HU) lesions (P=0.0003). DECT is a promising imaging method for the assessment of treatment response in GIST, as IRA might be a more robust response parameter than the Choi criteria. VNE CT data calculated from DECT may eliminate the need for acquisition of a separate unenhanced data set.
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2.65Impact points
Correlation of CT angiographic pulmonary artery obstruction scores with right ventricular dysfunction and clinical outcome in patients with acute pulmonary embolism.
European journal of radiology. 09/2011;
OBJECTIVE: To correlate CTA pulmonary artery obstruction scores (OS) with right ventricular dysfunction (RVD) and clinical outcome in patients with acute pulmonary embolism (PE). MATERIALS AND METHODS: In a prospective study of 50 patients (66±12.9 years) with PE pulmonary artery OS (Qanadli, Mastor... [more] OBJECTIVE: To correlate CTA pulmonary artery obstruction scores (OS) with right ventricular dysfunction (RVD) and clinical outcome in patients with acute pulmonary embolism (PE). MATERIALS AND METHODS: In a prospective study of 50 patients (66±12.9 years) with PE pulmonary artery OS (Qanadli, Mastora, and Mastora central) were assessed by two radiologists. To assess RVD all patients underwent echocardiography within 24h. Furthermore, RVD on CT was assessed by calculating the right ventricular/left ventricular (RV/LV) diameter ratios on transverse (RV/LVtrans) and four-chamber views (RV/LV4ch) as well as the RV/LV volume ratio (RV/LVvol). OS were correlated with RVD and the occurrence of adverse clinical outcomes (defined as death, need for intensive care treatment, or cardiac insufficiency ≥NYHA III). RESULTS: Mean Mastora, Qanadli, and Mastora central OS were 26.4±17.7, 12.6±9.9 and 7.5±9, respectively. Echocardiography demonstrated moderate and severe RVD in 10 and 5 patients, respectively. Patients with moderate and severe RVD showed significantly higher Mastora central scores than patients without RVD (14±10.8 vs. 5.9±7.8 [p=0.05]; 17.6±13.2 vs. 5.9±7.8 [p=0.038]). A relevant correlation (i.e. r≥0.6) between OS and CT parameters for RVD were only found for the Mastora score and the Mastora central score (RV/LV4ch: r=0.61 and 0.68, RV/LVvol: r=0.61 and 0.6). 18 patients experienced an adverse clinical outcome. None of the OS differed significantly between patients with and without adverse clinical outcome. CONCLUSION: Pulmonary artery obstruction scores can differentiate between patients with and without RVD. However, in this study, obstruction scores were not correlated to adverse clinical outcome.
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2.65Impact points
Quantification of left and right ventricular function and myocardial mass: Comparison of low-radiation dose 2nd generation dual-source CT and cardiac MRI.
European journal of radiology. 08/2011;
OBJECTIVE: To prospectively evaluate the accuracy of left and right ventricular function and myocardial mass measurements based on a dual-step, low radiation dose protocol with prospectively ECG-triggered 2nd generation dual-source CT (DSCT), using cardiac MRI (cMRI) as the reference standard. MATER... [more] OBJECTIVE: To prospectively evaluate the accuracy of left and right ventricular function and myocardial mass measurements based on a dual-step, low radiation dose protocol with prospectively ECG-triggered 2nd generation dual-source CT (DSCT), using cardiac MRI (cMRI) as the reference standard. MATERIALS AND METHODS: Twenty patients underwent 1.5T cMRI and prospectively ECG-triggered dual-step pulsing cardiac DSCT. This image acquisition mode performs low-radiation (20% tube current) imaging over the majority of the cardiac cycle and applies full radiation only during a single adjustable phase. Full-radiation-phase images were used to assess cardiac morphology, while low-radiation-phase images were used to measure left and right ventricular function and mass. Quantitative CT measurements based on contiguous multiphase short-axis reconstructions from the axial CT data were compared with short-axis SSFP cardiac cine MRI. Contours were manually traced around the ventricular borders for calculation of left and right ventricular end-diastolic volume, end-systolic volume, stroke volume, ejection fraction and myocardial mass for both modalities. Statistical methods included independent t-tests, the Mann-Whitney U test, Pearson correlation statistics, and Bland-Altman analysis. RESULTS: All CT measurements of left and right ventricular function and mass correlated well with those from cMRI: for left/right end-diastolic volume r=0.885/0.801, left/right end-systolic volume r=0.947/0.879, left/right stroke volume r=0.620/0.697, left/right ejection fraction r=0.869/0.751, and left/right myocardial mass r=0.959/0.702. Mean radiation dose was 6.2±1.8mSv. CONCLUSIONS: Prospectively ECG-triggered, dual-step pulsing cardiac DSCT accurately quantifies left and right ventricular function and myocardial mass in comparison with cMRI with substantially lower radiation exposure than reported for traditional retrospective ECG-gating.
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3.59Impact points
Functional imaging of lung cancer using dual energy CT: how does iodine related attenuation correlate with standardized uptake value of 18FDG-PET-CT?
European radiology. 08/2011; 22(1):93-103.
To investigate the correlation between maximum standardized uptake value (SUV(max)) of (18)FDG PET-CT and iodine-related attenuation (IRA) of dual energy CT (DECT) of primary tumours and (18)FDG PET-CT positive thoracic lymph nodes (LN) in patients with lung cancer. 37 patients with lung cancer (27 ... [more] To investigate the correlation between maximum standardized uptake value (SUV(max)) of (18)FDG PET-CT and iodine-related attenuation (IRA) of dual energy CT (DECT) of primary tumours and (18)FDG PET-CT positive thoracic lymph nodes (LN) in patients with lung cancer. 37 patients with lung cancer (27 NSCLC, 10 SCLC, 86 (18)FDG PET-CT positive thoracic LN) who underwent both (18)FDG PET-CT and DECT were analyzed. The mean study interval between (18)FDG PET-CT and DECT was ≤21 days in 17 patients. The mean and maximum IRA of DECT as well as of virtual unenhanced and virtual 120 kV images of DECT was analyzed and correlated to the SUV(max) of (18)FDG PET-CT in all tumours and (18)FDG PET-CT positive thoracic lymph nodes. Further subgroup analysis was performed for histological subtypes in all groups. A moderate correlation was found between SUV(max) and maximum IRA in all tumours (n = 37;r = 0.507;p = 0.025) whereas only weak or no correlation were found between SUV(max) and all other DECT measurements. A strong correlation was found in patients with study intervals ≤21 days (n = 17; r = 0.768;p = 0.017). Analysis of histological subtypes of lung cancer showed a strong correlation between SUV(max) and maximum IRA in the analysis of all patients with NSCLC (r = 0.785;p = 0.001) and in patients with NSCLC and study intervals ≤21 days (r = 0.876;p = 0.024). Thoracic LN showed moderate correlation between SUV(max) and maximum IRA in patients with study intervals ≤21 days (r = 0.654; p = 0.010) whereas a weak correlation was found between SUV(max) and maximum IRA in patients with study intervals >21 days (r = 0.299; p = 0.035). DECT could serve as a valuable functional imaging test for patients with NSCLC as the IRA of DECT correlates with SUV(max) of (18)FDG PET-CT.
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4.85Impact points
Multicenter comparison of high concentration contrast agent iomeprol-400 with iso-osmolar iodixanol-320: contrast enhancement and heart rate variation in coronary dual-source computed tomographic angiography.
Investigative radiology. 07/2011; 46(7):457-64.
To compare a contrast agent with high iodine concentration with an iso-osmolar contrast agent for coronary dual-source computed tomography angiography (DS-CTA), and to assess whether the contrast agent characteristics may affect the diagnostic quality of coronary DS-CTA. Patients were randomized to ... [more] To compare a contrast agent with high iodine concentration with an iso-osmolar contrast agent for coronary dual-source computed tomography angiography (DS-CTA), and to assess whether the contrast agent characteristics may affect the diagnostic quality of coronary DS-CTA. Patients were randomized to receive either 80 mL of iodixa:nol-320 (Visipaque, GE Healthcare, Chalfont St. Giles, United Kingdom) or iomeprol-400 (Iomeron, Bracco Imaging SpA, Milan, Italy) at 5 mL/s. Mean, minimum, maximum heart rate, and its variation (max-min) were assessed during calcium scoring scan and coronary DS-CTA. Three off-site readers independently evaluated the image sets in terms of technical adequacy, reasons for inadequacy, vessel visualization, diagnostic confidence (based on a 5-point scale), and arterial contrast opacification in Hounsfield units (HUs). Ninety-six patients were included in the final evaluation. No significant differences were observed for pre- and postdose heart rate values for iomeron-400 compared with iodixanol-320, and changes in heart rate variation were also not significantly different (-2.3 ± 11.7 vs. -2.5 ± 7.3 bpm, P > 0.1). Contrast measurements in all analyzed vessels were significantly higher for iomeprol-400 (mean, 391.5-441.4 HU) compared with iodixanol-320 (mean, 332.3-365.5 HU, all P ≤ 0.0038). There was no significant difference in qualitative visualization of coronary arteries (mean scores, 4.3-4.5 for iomeprol, 4.1-4.3 for iodixanol, P = 0.15-0.28), or in diagnostic confidence scores. HU were inversely correlated with the number of insufficiently opacified segments (all readers P ≤ 0.0006). The high-iodine concentration contrast medium iomeprol-400 demonstrated significant benefit for coronary arterial enhancement compared with the iso-osmolar contrast medium iodixanol-320 when administered at identical flow rates and volumes for coronary DS-CTA. In addition, higher enhancement levels were found to be associated with lower numbers of inadequately visualized segments. Finally, observed mean heart rate changes after intravenous contrast injection were generally small during the examination and comparable for both agents.
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4.85Impact points
Gadofosveset: parameter optimization for steady-state imaging of the thoracic and abdominal vasculature.
Investigative radiology. 06/2011; 46(11):678-85.
Comparison of 3 optimized pulse sequences for thoracoabdominal contrast-enhanced magnetic-resonance angiography by signal-to-noise measurements and time-dependent T1 mapping in the steady state after injection of 0.03 mmol/kg BW gadofosveset. After institutional review board approval, 15 healthy vol... [more] Comparison of 3 optimized pulse sequences for thoracoabdominal contrast-enhanced magnetic-resonance angiography by signal-to-noise measurements and time-dependent T1 mapping in the steady state after injection of 0.03 mmol/kg BW gadofosveset. After institutional review board approval, 15 healthy volunteers (19-46 years, mean age: 31.5 years) were included in this prospective, intraindividual comparison study. All examinations were performed at 1.5 T. Three pulse sequences: volume interpolated breath-hold examination (VIBE) sequences as VIBESEMI (echo time [TE]: 1.64 milliseconds, repetition time [TR]: 3.77 milliseconds, FA: 15 degrees, voxel size: 1.2 × 1.2 × 1.2 mm) with short TR, VIBEOPT (TE: 2.2 milliseconds, TR: 5.2, FA: 15 degree, voxel size: 1.2 × 1.2 × 1.2 mm) with long TR, and a typical 3-dimensional fast low angle shot (FLASH) sequence (TE: 1.39 milliseconds, TR: 3.77 milliseconds, FA: 25 degree, voxel size: 1.0 × 0.8 × 1.0 mm) were repeated 10, 20, 30, and 40 minutes after the injection of 0.03 mmol/kg BW gadofosveset (mean dose: 9.7 mL). Mean signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were computed for the aorta and the inferior vena cava (IVC). Three-dimensional gradient echo sequences with variable flip angles were performed for T1 mapping 0 to 50 minutes postinjection (p.i.). Additional phantom measurements were performed to compare the sequences. Significantly higher SNR values of the FLASH were found at every point compared with VIBEOPT (P = 0.002-P = 0.004), but only 10, respectively, 20 minutes p.i. to VIBESEMI. No significant differences of SNR were obtained between VIBESEMI and VIBEOPT. In the aorta, the maximal percentage gain of SNR was 29.2% for 3D-FLASH compared with VIBESEMI. Similar, but mostly not significant, results were obtained regarding the SNR in the IVC with the 3D-FLASH sequence yielding higher SNR versus both comparators (P = 0.007-P = 0.466). Except 10 minutes p.i., CNR analysis yielded higher values for the VIBESEMI versus both comparators in the aorta as well as in the IVC. No statistical significant difference was found for the VIBESEMI versus the 3D-FLASH sequence in all comparisons. Regarding the phantom measurements, statistically significant higher SNR was found for the VIBESEMI versus the 3D-FLASH. The T1 time in the aorta decreased p.i. from 1227 ± 383 milliseconds to 141 ± 27 milliseconds and showed over the time a slow reincrease to 175 ± 29 milliseconds at 50 minutes p.i. Ten to 30 minutes after injection of gadofosveset, a relatively constant longitudinal relaxation is given. In this steady state, no additional improvements were obtained by theoretically optimized sequence parameters in the VIBEOPT with a longer TR.
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6.34Impact points
Evaluation of heavily calcified vessels with coronary CT angiography: comparison of iterative and filtered back projection image reconstruction.
Radiology. 06/2011; 260(2):390-9.
To prospectively compare traditional filtered back projection (FBP) and iterative image reconstruction for the evaluation of heavily calcified arteries with coronary computed tomography (CT) angiography. The study had institutional review board approval and was HIPAA compliant. Written informed cons... [more] To prospectively compare traditional filtered back projection (FBP) and iterative image reconstruction for the evaluation of heavily calcified arteries with coronary computed tomography (CT) angiography. The study had institutional review board approval and was HIPAA compliant. Written informed consent was obtained from all patients. Fifty-five consecutive patients (35 men, 20 women; mean age, 58 years ± 12 [standard deviation]) with Agatston scores of at least 400 underwent coronary CT angiography and cardiac catheterization. Image data were reconstructed with both FBP and iterative reconstruction techniques with corresponding cardiac algorithms. Image noise and subjective image quality were compared. To objectively assess the effect of FBP and iterative reconstruction on blooming artifacts, volumes of circumscribed calcifications were measured with dedicated volume analysis software. FBP and iterative reconstruction series were independently evaluated for coronary artery stenosis greater than 50%, and their diagnostic accuracy was compared, with cardiac catheterization as the reference standard. Statistical analyses included paired t tests, Kruskal-Wallis analysis of variance, and a modified McNemar test. Image noise measured significantly lower (P = .011-.035) with iterative reconstruction instead of FBP. Image quality was rated significantly higher (P = .031 and .042) with iterative reconstruction series than with FBP. Calcification volumes measured significantly lower (P = .019 and .026) with iterative reconstruction (44.3 mm(3) ± 64.7 and 46.2 mm(3) ± 68.8) than with FBP (54.5 mm(3) ± 69.5 and 56.3 mm(3) ± 72.5). Iterative reconstruction significantly improved some measures of per-segment diagnostic accuracy of coronary CT angiography for the detection of significant stenosis compared with FBP (accuracy: 95.9% vs 91.8%, P = .0001; specificity: 95.8% vs 91.2%, P = .0001; positive predictive value: 76.9% vs 61.1%, P = .0001). Iterative reconstruction reduces image noise and blooming artifacts from calcifications, leading to improved diagnostic accuracy of coronary CT angiography in patients with heavily calcified coronary arteries.
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3.59Impact points
Coronary CT angiography: image quality, diagnostic accuracy, and potential for radiation dose reduction using a novel iterative image reconstruction technique-comparison with traditional filtered back projection.
European radiology. 05/2011; 21(10):2130-8.
To compare image noise, image quality and diagnostic accuracy of coronary CT angiography (cCTA) using a novel iterative reconstruction algorithm versus traditional filtered back projection (FBP) and to estimate the potential for radiation dose savings. Sixty five consecutive patients (48 men; 59.3 ±... [more] To compare image noise, image quality and diagnostic accuracy of coronary CT angiography (cCTA) using a novel iterative reconstruction algorithm versus traditional filtered back projection (FBP) and to estimate the potential for radiation dose savings. Sixty five consecutive patients (48 men; 59.3 ± 7.7 years) prospectively underwent cCTA and coronary catheter angiography (CCA). Full radiation dose data, using all projections, were reconstructed with FBP. To simulate image acquisition at half the radiation dose, 50% of the projections were discarded from the raw data. The resulting half-dose data were reconstructed with sinogram-affirmed iterative reconstruction (SAFIRE). Full-dose FBP and half-dose iterative reconstructions were compared with regard to image noise and image quality, and their respective accuracy for stenosis detection was compared against CCA. Compared with full-dose FBP, half-dose iterative reconstructions showed significantly (p = 0.001 - p = 0.025) lower image noise and slightly higher image quality. Iterative reconstruction improved the accuracy of stenosis detection compared with FBP (per-patient: accuracy 96.9% vs. 93.8%, sensitivity 100% vs. 100%, specificity 94.6% vs. 89.2%, NPV 100% vs. 100%, PPV 93.3% vs. 87.5%). Iterative reconstruction significantly reduces image noise without loss of diagnostic information and holds the potential for substantial radiation dose reduction from cCTA.
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4.85Impact points
Optimization of contrast material delivery for dual-energy computed tomography pulmonary angiography in patients with suspected pulmonary embolism.
Investigative radiology. 05/2011; 47(1):78-84.
To prospectively compare subjective and objective measures of image quality using 4 different contrast material injection protocols in dual-energy computed tomography pulmonary angiography (CTPA) studies of patients with suspected pulmonary embolism. A total of 100 consecutive patients referred for ... [more] To prospectively compare subjective and objective measures of image quality using 4 different contrast material injection protocols in dual-energy computed tomography pulmonary angiography (CTPA) studies of patients with suspected pulmonary embolism. A total of 100 consecutive patients referred for CTPA for the exclusion of pulmonary embolism were randomized into 1 of 4 contrast material injection protocols manipulating iodine concentration and iodine delivery rate (IDR, expressed as grams of iodine per second): Iomeprol 400 at 3 mL/s (IDR = 1.2 gI/s), iomeprol 400 at 4 mL/s (IDR = 1.6 gI/s), iomeprol 300 at 5.4 mL/s (IDR = 1.6 gI/s), or iomeprol 300 at 4 mL/s (IDR = 1.2 gI/s). Total iodine delivery was held constant. Dual-energy CTPA of the lungs were acquired and used to calculate virtual 120 kV CTPA images as well as iodine perfusion maps. Attenuation values in the thoracic vasculature and image quality of virtual 120 kV CTPAs were compared between groups. Iodine perfusion maps were also compared by identifying differences in the extent of beam-hardening artifacts and subjective image quality. Protocols with an IDR of 1.6 gI/s provided the best attenuation profiles. CTPA image quality was greatest in the high concentration, high IDR (1.6 gI/s) protocol (P < 0.05 for all group comparisons) with no differences between the other groups (all P ≥ 0.05). Extent of beam-hardening artifacts and perfusion map image quality was significantly better using the high concentration, high IDR protocol as compared with all groups (P < 0.05 for all comparisons) and significantly worse using the low concentration, low IDR protocol as compared with all groups (all P ≥ 0.05); no difference was found between the high concentration, low IDR protocol and the low concentration, high IDR protocol (P = 0.73 for comparison of beam-hardening artifacts; P = 0.50 for comparison of perfusion map image quality). High iodine concentration and high IDR contrast material delivery protocols provide the best image quality of both CTPA and perfusion map images of the lung through high attenuation in the pulmonary arteries and minimization of beam-hardening artifacts.
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2.95Impact points
Radiation dose at coronary CT angiography: second-generation dual-source CT versus single-source 64-MDCT and first-generation dual-source CT.
AJR. American journal of roentgenology. 05/2011; 196(5):W550-7.
The purpose of this study was to assess the radiation doses of different coronary CTA (CTA) protocols: second-generation dual-source 128-MDCT, first-generation dual-source 64-MDCT, and single-source 64-MDCT. Thermoluminescent dosimetry was used to determine scanner-specific dose coefficients for sta... [more] The purpose of this study was to assess the radiation doses of different coronary CTA (CTA) protocols: second-generation dual-source 128-MDCT, first-generation dual-source 64-MDCT, and single-source 64-MDCT. Thermoluminescent dosimetry was used to determine scanner-specific dose coefficients for standard coronary CTA of an anthropomorphic phantom. These coefficients were used to estimate the effective doses (EDs) of retrospectively gated, prospectively triggered, and prospectively triggered high pitch coronary CTA performed at 100 and 120 kV. The coronary CTA protocols used in imaging of 43 patients undergoing dual-source 128-MDCT were analyzed for ED, image quality, and signal-to-noise ratio. Regardless of coronary CTA protocol and CT system, imaging at 100 kV lowered the ED 40-50%. In retrospectively gated 120-kV coronary CTA, the ED ranged from 5.7 to 10.7 mSv and was approximately 50% lower with single-source 64-MDCT than with either DSCT protocol. In prospectively triggered 120-kV coronary CTA, the ED ranged from 3.8 to 4.0 mSv. The lowest ED of all protocols (1.3 mSv) was observed in prospectively triggered high-pitch 100-kV coronary CTA performed with dual-source 128-MDCT. Patient measurements showed similar dose reductions for prospective triggering and low voltage settings without an influence on signal-to-noise ratio or image quality. A combination of prospective triggering with low voltage settings is an effective measure for reducing the ED of coronary CTA to values of 2-4 mSv independent of scanner system. Further dose reduction to nearly 1 mSv can be achieved with high-pitch prospectively triggered coronary CTA.
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2.65Impact points
Venous thromboembolism: additional diagnostic value and radiation dose of pelvic CT venography in patients with suspected pulmonary embolism.
European journal of radiology. 04/2011; 80(1):50-3.
To assess the additional diagnostic value of indirect CT venography (CTV) of the pelvis and upper thighs performed after pulmonary CT angiography (CTA) for the diagnosis of venous thromboembolism (VTE). In a retrospective analysis, the radiology information system entries between January 2003 and De... [more] To assess the additional diagnostic value of indirect CT venography (CTV) of the pelvis and upper thighs performed after pulmonary CT angiography (CTA) for the diagnosis of venous thromboembolism (VTE). In a retrospective analysis, the radiology information system entries between January 2003 and December 2007 were searched for patients who received pulmonary CTA and additional CTV of the pelvis and upper thighs. Of those patients, the radiology reports were reviewed for the diagnosis of pulmonary embolism (PE) and deep venous thrombosis (DVT) in the pelvic veins and veins of the upper thighs. In cases with an isolated pelvic thrombosis at CTV (i.e. which only had a thrombosis in the pelvic veins but not in the veins of the upper thigh) ultrasound reports were reviewed for the presence of DVT of the legs. The estimated radiation dose was calculated for pulmonary CTA and for CTV of the pelvis. In the defined period 3670 patients were referred to our institution for exclusion of PE. Of those, 642 patients (353 men, 289 women; mean age, 65±15 years, age range 18-98 years) underwent combined pulmonary CTA and CTV. Among them, PE was found in 227 patients (35.4%). In patients without PE CTV was negative in all cases. In patients with PE, CTV demonstrated pelvic thrombosis in 24 patients (3.7%) and thrombosis of the upper thighs in 43 patients (6.6%). Of those patients 14 (2.1%) had DVT in the pelvis and upper thighs. In 10 patients (1.5%) CTV showed an isolated pelvic thrombosis. Of those patients ultrasound reports were available in 7 patients, which revealed DVT of the leg veins in 5 cases (1%). Thus, the estimated prevalence of isolated pelvic thrombosis detected only by pelvic CTV ranges between 1-5/642 patients (0.1-0.7%). Radiation dose ranges between 4.8 and 9.7 mSv for additional CTV of the pelvis. CTV of the pelvis performed after pulmonary CTA is of neglectable additional diagnostic value for the detection of VTE, because the additional radiation dose is high and isolated pelvic DVT is very rare. Venous imaging of the legs (preferably by radiation-free ultrasound) is sufficient for the diagnosis of underlying DVT in patients with suspected PE.
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