Characterization of noncalcified coronary plaques and identification of culprit lesions in patients with acute coronary syndrome by 64-slice computed tomography.

OBJECTIVES: We sought to characterize noncalcified coronary atherosclerotic plaques in culprit and remote coronary atherosclerotic lesions in patients with acute coronary syndrome (ACS) with 64-slice computed tomography (CT). BACKGROUND: Lower CT density, positive remodeling, and adjacent spotty coronary calcium are characteristic vessel changes in unstable coronary plaques. METHODS: Of 147 consecutive patients who underwent contrast-enhanced 64-slice CT examination for coronary artery visualization, 101 (ACS; n = 21, non-ACS; n = 80) having 228 noncalcified coronary atherosclerotic plaques (NCPs) were studied. Each NCP detected within the vessel wall was evaluated by determining minimum CT density, vascular remodeling index (RI), and morphology of adjacent calcium deposits. RESULTS: The CT visualized more NCPs in ACS patients (65 lesions, 3.1 +/- 1.2/patient) than in non-ACS patients (163 lesions, 2.0 +/- 1.1/patient). Minimum CT density (24 +/- 22 vs. 42 +/- 29 Hounsfield units [HU], p < 0.01), RI (1.14 +/- 0.18 vs. 1.08 +/- 0.19, p = 0.02), and frequency of adjacent spotty calcium of NCPs (60% vs. 38%, p < 0.01) were significantly different between ACS and non-ACS patients. Frequency of NCPs with minimum CT density <40 HU, RI >1.05, and adjacent spotty calcium was approximately 2-fold higher in the ACS group than in the non-ACS group (43% vs. 22%, p < 0.01). In the ACS group, only RI was significantly different between 21 culprit and 44 nonculprit lesions (1.26 +/- 0.16 vs. 1.09 +/- 0.17, p < 0.01), and a larger RI (> or = 1.23) was independently related to the culprit lesions (odds ratio: 12.3; 95% confidential interval: 2.9 to 68.7, p < 0.01), but there was a substantial overlap of the distribution of RI values in these 2 groups of lesions. CONCLUSIONS: Sixty-four-slice CT angiography demonstrates a higher prevalence of NCPs with vulnerable characteristics in patients with ACS as compared with stable clinical presentation.

Comprehensive evaluation of noncalcified coronary plaque characteristics detected using 64-slice computed tomography in patients with proven or suspected coronary artery disease.

BACKGROUND: Multislice computed tomography has recently been shown to have the potential to characterize noncalcified coronary atherosclerotic lesions (NCALs). We evaluated the relationship among computed tomography (CT) density, arterial remodeling, and the adherent calcium morphology of NCALs detected using 64-slice CT. METHODS: We studied 138 patients with proven or suspected coronary artery disease who underwent contrast-enhanced 64-slice CT examination. For each NCAL detected within the vessel wall, we determined the minimum CT density, remodeling index (RI = lesion/reference vessel area), and the presence or absence of coronary calcium in or adjacent to each NCAL and its morphology. Intravascular ultrasound (IVUS) was additionally performed in a subset of 21 patients. RESULTS: A total of 202 NCALs were detected in 97 patients. The mean CT density of 98 lesions with positive remodeling (PR) (RI >1.05) was significantly lower than that of 104 lesions without PR (25 +/- 23 vs 56 +/- 28 Hounsfield units, P < .001); and spotty calcium was more frequently observed with the PR lesions than non-PR lesions (59% vs 22%, P < .001). The mean CT density of the PR lesions with spotty calcium (n = 58) was substantially lower than that of the non-PR lesions without adherent calcium (n = 45) (20 +/- 20 vs 67 +/- 24 Hounsfield units, P < .001). Evaluation of the components, RI, and adherent calcium morphology of 38 NCALs by 64-slice CT was in close agreement with the IVUS findings. CONCLUSIONS: Lower CT density, PR, and adherent spotty calcium, which may indicate plaque vulnerability, are intimately co-related in NCALs detected using 64-slice CT; these findings are consistent with those of IVUS.