Background-We investigated the ability of multidetector spiral computed tomography (MDCT) to detect atherosclerotic plaque in nonstenotic coronary arteries. Methods and Results-In 22 patients without significant coronary stenoses, contrast-enhanced MDCT (0.75-mm collimation, 420-ms rotation) and intravascular ultrasound (IVUS) of one coronary artery were performed. A total of 83 coronary segments were imaged by IVUS (left main, 19; left anterior descending, 51; left circumflex, 4; right coronary, 9). MDCT data sets were evaluated for the presence and volume of plaque in the coronary artery segments. Results were compared with IVUS in a blinded fashion. For the detection of segments with any plaque, MDCT had a sensitivity of 82% (41 of 50) and specificity of 88% (29 of 33). For calcified plaque, sensitivity was 94% (33 of 36) and specificity 94% (45 of 47). Coronary segments containing noncalcified plaque were detected with a sensitivity of 78% (35 of 45) and specificity of 87% (33 of 38), but presence of exclusively noncalcified plaque was detected with only 53% sensitivity (8 of 15). If analysis was limited to the 41 proximal segments (segments 1, 5, 6, and 11 according to American Heart Association classification), sensitivity and specificity were 92% and 88% for any plaque, 95% and 91% for calcified plaque, and 91% and 89% for noncalcified plaque. MDCT substantially underestimated plaque volume per segment as compared with IVUS (24Ϯ35 mm 3 versus 43Ϯ60 mm 3 , PϽ0.001). Conclusions-The results indicate the potential of MDCT to detect coronary atherosclerotic plaque in patients without significant coronary stenoses. However, further improvements in image quality will be necessary to achieve reliable assessment, especially of noncalcified plaque throughout the coronary tree. Key Words: tomography Ⅲ atherosclerosis Ⅲ coronary disease D irect, noninvasive imaging of coronary atherosclerotic plaque might potentially improve risk stratification for the occurrence of coronary events in selected asymptomatic individuals. 1,2 Initial reports of the ability of contrastenhanced multidetector spiral computed tomography (MDCT) to visualize noncalcified coronary atherosclerotic plaque have thus received widespread attention. [3][4][5][6][7][8] However, the ability of MDCT to detect and quantify coronary atherosclerotic plaque in vivo has never been systematically validated. We therefore evaluated the ability of MDCT with submillimeter slice collimation to detect and quantify coronary atherosclerotic plaque in patients without significant coronary artery stenoses in comparison with intravascular ultrasound (IVUS). Methods PatientsIn 22 patients (14 male, 8 female; mean age, 58 years), MDCT was performed as part of research protocols that enrolled consecutive subjects who were scheduled for invasive coronary angiography for clinical reasons. In all patients, coronary artery stenoses (Ն50% diameter reduction) had been ruled out by coronary angiography, and an IVUS study of the largest coronary vessel was performed. Patients wi...

We introduce the concept of noninvasive detection and characterization of coronary atherosclerotic lesions in patients with ACS by MDCT. We identified differences in lesion morphology and plaque composition between culprit lesions in ACS and stable lesions in ACS or stable angina, consistent with previous intravascular ultrasound studies.

Background To determine whether high-risk plaque as detected by coronary computed tomography angiography (CTA) permits improved early diagnosis of acute coronary syndrome (ACS) independent to the presence of significant CAD in acute chest pain patients. Objectives The primary aim was to determine whether high-risk plaque features, as detected by CTA in the emergency department, may improve diagnostic certainty of ACS independent and incremental to the presence of significant CAD and clinical risk assessment in patients with acute chest pain but without objective evidence of myocardial ischemia or myocardial infarction. Methods We included patients randomized to the CCTA arm of ROMICAT II trial. Readers assessed coronary CTA qualitatively for the presence of non-obstructive CAD (1-49% stenosis), significant CAD (≥50% or ≥70% stenosis), and the presence of at least 1 of the high-risk plaque features (positive remodeling, low < 30 Hounsfield Units plaque, napkin-ring sign, spotty calcium). In logistic regression analysis, we determined the association of high-risk plaque with ACS [myocardial infarction (MI) or unstable angina pectoris (UAP)] during the index hospitalization and whether this was independent of significant CAD and clinical risk assessment. Results Overall 37 of 472 patients who underwent coronary CTA with diagnostic image quality (mean age 53.9±8.0 years, 52.8% men) had ACS (7.8%; MI n=5, UAP n=32)]. CAD was present in 262 (55.5%) patients [non-obstructive CAD 217 (46.0%) patients, significant CAD with ≥50% stenosis 45 (9.5%) patients]. High-risk plaques were more frequent in patients with ACS and remained a significant predictor of ACS (OR 8.9, 95% CI 1.8-43.3, p=0.006) after adjusting for ≥50% stenosis (OR 38.6, 95% CI 14.2-104.7, p<0.001) and clinical risk assessment (age, gender, number of cardiovascular risk factors). Similar results were observed after adjusting for ≥70% stenosis. Conclusions In patients presenting to the ED with acute chest pain but negative initial electrocardiogram and troponin, presence of high-risk plaque on coronary CTA increases the likelihood of ACS independent of significant CAD and clinical risk assessment (age, gender, and number of cardiovascular risk factors).