Abstract 205: Detection of Vulnerable Plaque by Multislice Computed Tomography, Comparative Study With Optical Coherence Tomography
Back ground: Acute coronary syndrome is commonly caused by disruption of vulnerable plaque that is characterized by thin fibrous cap (<65 μm) and large lipid pool. Noninvasive detection of vulnerable plaque using multislice computed tomography (MSCT) could be useful for risk stratification in patients with coronary artery disease. The purpose of this study is to investigate the possibility of MSCT to detect a thin-capped fibroatheroma (TCFA) by comparing the optical coherence tomography (OCT) findings.
Methods and results: From January 2008 to March 2009, 77 lesions (19 unstable angina pectoris (uAP) culprit, 19 uAP non-culprit and 39 stable angina pectoris) in 43 patients were evaluated by MSCT and OCT. Based on OCT findings, lesions were classified as TCFA group (n=40) and non-TCFA group (n=37). The mean CT density value of the lesion was significantly lower in TCFA group (63.4±25.1 vs. 137.4±60.9 Hounsfield units (HU), p<0.0001). The optimal thresholds of mean CT density value identified by receiver operating curve was 68.5 HU (the area under the curve was 0.859) with a sensitivity of 55% and a specificity of 81%. Signet ring like appearance was observed more frequently in the TCFA group (57.5% vs. 13.5%, p<0.0001). Positive vessel remodeling was identified more frequently in TCFA group (67.5% vs. 18.9%, p<0.0001). There was no significant difference in spotty calcification between two groups (35.0 % vs. 24.3%, p=0.31). In multivariate analysis, the independent predictors of TCFA were positive vessel remodeling (Odds ratio (OR) 6.59; 95% confidential interval (CI), 1.99 – 21.71; p = 0.002), mean CT density value ≤68.5HU (OR 4.31; 95%CI, 1.26 – 14.80; p=0.020), and signet ring like appearance (OR 3.72; 95%CI, 1.02 – 13.65; p=0.047). Presence of all 3 findings of positive vessel remodeling, mean CT density value ≤68.5 and signet ring like appearance provided a high positive predictive value of 93%. Absence of all 3 findings showed a high negative predictive value of 88%.
Conclusion: The parameters of MSCT associated with TCFA identified by OCT were positive vessel remodeling, low mean CT density value and signet ring like appearance. MSCT may have potential to detect a vulnerable plaque and assess the risk of patients with coronary artery disease noninvasively.