Abstract 3408: Assessment of Plaque Characteristics in Acute Coronary Syndrome by Multidetector Computed Tomography
Backgrounds: Multidetector Computed Tomography (MDCT) permits non-invasive assessment of arterial remodeling and plaque composition in the atherosclerotic coronary lesions, which may play an important role in the progression of atherosclerosis. We have reported that intra-plaque enhancement (IPE) is closely associated with the progressive coronary lesions. In this study, we evaluated arterial remodeling, plaque composition, and frequency of IPE in the culprit lesion of acute coronary syndrome (ACS), and compared the results with those in stable angina (SA).
Methods: One hundred nine patients with ACS (n=38) or SA (n=71) underwent MDCT and invasive coronary angiography (CAG). In CAG, a total of 138 significant stenoses were detected and assessed by 16-slice MDCT. Assessment of the lesions was performed in the cross-sectional images. The vessel area was measured at both the lesion and the reference segment. The remodeling index (RI) was calculated by dividing the vessel area of the lesion by the reference segment. Positive remodeling (PR) was defined as RI higher than 1.1. Mean CT density (CTD) was obtained and plaque composition was classified into one of three categories of soft plaques (CTD<70HU), fibrous plaques (70HU≤CTD<128HU), or calcified plaques by CTD. IPE was defined as a partial enhancement not by dense calcification in lower CTD plaque. RI, plaque composition, and frequency of IPE were compared between culprit lesions of ACS and SA.
Results: Thirty five ACS lesions and 103 stable lesions were analyzed. Mean RI was higher in ACS lesions than in SA (1.14±0.21 vs 0.92±0.20 , p<0.01), and PR was more frequently observed in ACS lesions (50% vs 14%, p<0.01). CTD was 83 HU in ACS, and 103 HU in SA. Soft plaque (CTD<70) was more frequently observed in ACS than in SA (74% vs 54%, p<0.05). Frequency of IPE was significantly higher in ACS than in SA (48.6% vs 26.2%, p<0.05). RI and the presence of soft plaque showed significant correlation. No significant correlation was observed either between RI and IPE or between soft plaque and IPE.
Conclusions: Differences in arterial remodeling and plaque composition between culprit lesion of ACS and SA were confirmed in MDCT. IPE might represent a progressive feature of the coronary lesions.