Abstract 21405: Dynamic Enhancement Pattern is Different Between Unstable and Stable Coronary Plaque: Analysis With 320-Row Area Detector Computed Tomography

Abstract

Introduction: Intraplaque neovascularization is a marker of unstable coronary plaque. We investigated a difference in dynamic enhancement pattern of coronary plaque between stable and unstable angina pectoris, using 320-row area detector computed tomography (CT), which enables whole-heart volumetric acquisition in a single gantry rotation. Hypothesis & Methods: We analyzed 106 coronary plaque segments in 38 patients (mean age 69.8±8.3 years, 32 male) with angina pectoris (13 stable, 25 unstable) who underwent coronary CT and percutaneous coronary intervention (PCI). Coronary plaques were evaluated using 320-row area detector CT with and without contrast enhancement. Culprit plaques (PCI target) of unstable patients were defined as unstable plaque(n=35), whereas culprit plaques of stable patients and non-culprit plaque were defined as stable plaque(n=71). Coronary plaque without contrast enhancement, corresponding to the plaque detected by contrast enhanced CT, was identified using unique calcification as a landmark. The mean Hounsfield unit (HU) in the coronary plaque was measured, and the presence of positive vascular remodeling was evaluated. Coronary artery stenosis was quantified by coronary angiography. Results: Unstable patients were younger than stable patients (66.6±7.2 vs 76.1±6.7 years, p<0.01). Positive vascular remodeling and spotty calcification was more frequently observed in unstable than stable patients (68.4% vs 15.4%, p< 0.01 and 45.5% vs 86.4%, p<0.05 respectively). Coronary artery stenosis was not different between the 2 groups. In CT without contrast enhancement, plaque HU was not different between the 2 groups (unstable: 25.0±32.4 vs stable: 24.9±33.1). With contrast enhancement, plaque HU was significantly elevated in both groups from those without contrast enhancement to 53.9±24.1 (unstable: p<0.01) and to 42.6±33.5 (stable: p<0.01). Unstable plaque showed higher enhancement (delta HU) than stable plaque (28.9±23.5 vs 17.7±25.5, p=0.024). Conclusions: Dynamic enhancement pattern is different between unstable and stable coronary plaque. Compared to stable plaque, unstable plaque shows higher contrast enhancement, suggesting the increased neovascularization in the plaque.