Coronary artery calcification score by multislice computed tomography predicts the outcome of dobutamine cardiovascular magnetic resonance imaging
University of Groningen, Groningen, Groningen, Netherlands European Radiology
(Impact Factor: 4.01).
07/2005; 15(6):1128-34. DOI: 10.1007/s00330-005-2706-0
The aim of this study was to determine whether a coronary artery calcium (CAC) score of less than 11 can reliably rule out myocardial ischemia detected by dobutamine cardiovascular magnetic resonance imaging (CMR) in patients suspected of having myocardial ischemia. In 114 of 136 consecutive patients clinically suspected of myocardial ischemia with an inconclusive diagnosis of myocardial ischemia, dobutamine CMR was performed and the CAC score was determined. The CAC score was obtained by 16-row multidetector compued tomography (MDCT) and was calculated according to the method of Agatston. The CAC score and the results of the dobutamine CMR were correlated and the positive predictive value (PPV) and the negative predictive value (NPV) of the CAC score for dobutamine CMR were calculated. A total of 114 (87%) of the patients were eligible for this study. There was a significant correlation between the CAC score and dobutamine CMR (p<0.001). Patients with a CAC score of less than 11 showed no signs of inducible ischemia during dobutamine CMR. For a CAC score of less than 101, the NPV and the PPV of the CAC score for the outcome of dobutamine CMR were, respectively, 0.96 and 0.29. In patients with an inconclusive diagnosis of myocardial ischemia a MDCT CAC score of less than 11 reliably rules out myocardial ischemia detected by dobutamine CMR.
Available from: Elena Aikawa
- "Clinical studies show that calcium score is an excellent predictor of cardiovascular morbidity and mortality, and coronary calcification is the most widely used marker of the advancement of atherosclerosis [1,2]; however, the link between calcification and plaque rupture is still controversial [3▪]. Moreover, the identification of atheromas prone to rupture and cause subsequent acute cardiovascular events, such as myocardial infarction and stroke, is still challenging. "
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ABSTRACT: Purpose of review
Atherosclerotic plaque rupture and subsequent acute events, such as myocardial infarction and stroke, contribute to the majority of cardiovascular-related deaths. Calcification has emerged as a significant predictor of cardiovascular morbidity and mortality, challenging previously held notions that calcifications stabilize atherosclerotic plaques. In this review, we address this discrepancy through recent findings that not all calcifications are equivalent in determining plaque stability.
The risk associated with calcification is inversely associated with calcification density. As opposed to large calcifications that potentially stabilize the plaque, biomechanical modeling indicates that small microcalcifications within the plaque fibrous cap can lead to sufficient stress accumulation to cause plaque rupture. Microcalcifications appear to derive from matrix vesicles enriched in calcium-binding proteins that are released by cells within the plaque. Clinical detection of microcalcifications has been hampered by the lack of imaging resolution required for in-vivo visualization; however, recent studies have demonstrated promising new techniques to predict the presence of microcalcifications.
Microcalcifications play a major role in destabilizing atherosclerotic plaques. The identification of critical characteristics that lead to instability along with new imaging modalities to detect their presence in vivo may allow early identification and prevention of acute cardiovascular events.
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ABSTRACT: Wall motion imaging with cardiac magnetic resonance imaging (CMR) provides important functional information about global and regional myocardial function. This review will give an overview of the current state of myocardial wall motion imaging, especially focusing on the clinical role of dobutamine stress CMR in ischaemic heart disease. Dobutamine stress CMR provides functional information on the myocardium under conditions of pharmacologically induced stress. High-dose dobutamine is used for wall motion analysis of the left ventricle. Wall motion abnormalities are indicative of myocardial ischaemia and occur in the ischaemic cascade before the onset of chest pain and ECG abnormalities. As a result of technological advances, dobutamine stress CMR has evolved towards a very accurate cardiac stress test. The current state of dobutamine stress CMR allows us to obtain cine MR images with high spatial and temporal resolution in rest and during stress. The use of myocardial tagging has improved the diagnostic accuracy even further. The addition of first-pass perfusion imaging at peak dose dobutamine might enhance accuracy even more. Besides being able to detect myocardial ischaemia, low-dose dobutamine can be used to assess myocardial viability. With these capabilities, viability, wall motion and myocardial perfusion can be assessed in a single examination. The safety and feasibility of dobutamine stress CMR has been proven. The technique and clinical implications are discussed.
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ABSTRACT: The objective of this study was to investigate the factors that may influence image quality on multidetector computed tomography (MDCT) coronary angiography (CA).
Two hundred twenty-four consecutive patients (161 men and 63 women; mean age, 52 years; age range, 34-76 years) evaluated with MDCT CA were included in the study. The evaluation of the quality of the patients' images was mainly based on the contrast material phase (early phase, optimal phase, or late phase) and the level of stepladder artifact (none, acceptable, or unacceptable). In addition, factors such as patient selection, patient preparation, scanning, processing, and steps of analysis, which may be affecting the quality of a final image, were examined independently.
Patients who could not achieve sufficient breath-holding despite multiple breath exercises, those with a calcium score of 500 or higher, those with a heart rate greater than 90 bpm after metoprolol administration (because of shortening of the diastolic phase in the most still period), and those whose scanning was not completed were excluded from the study. The results for the remaining 224 patients were evaluated. Based on the contrast phase, there were 66 (29.5%) patients in the first group (early), 93 (41.5%) in the second group (optimal), and 65 (29%) in the third group (late). Among the 224 patients, the images of 152 (67.9%) had no stepladder artifact, those of 67 (29.9%) were of acceptable image quality, and those of 5 (2.2%) were of unacceptable image quality.
It is important to obtain high-quality images to achieve correct interpretation with coronary artery CT angiography. This study aimed to describe a technique performed on 224 patients based on an array of factors ranging from patient selection to postprocessing. The results show that patient selection, cooperation with the patient, and breath-holding exercises play a very important role in obtaining the best images. In addition, a proper scanning technique (e.g., placement of electrocardiographic electrodes and contrast material phase) and postprocessing (e.g., reconstruction interval) may also contribute to obtaining high-quality images.
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