Characterization of culprit lesions in acute coronary syndromes using coronary dual-source CT angiography

Abstract

Objective We analyzed typical morphological features of coronary atherosclerotic plaques in acute coronary syndromes (ACS) using contrast-enhanced coronary Dual-Source CT angiography (CTA) in comparison to stable coronary lesions. Patients and methods Fifty-five patients with ACS and 55 controls with stable angina pectoris (SAP) with similar atherosclerotic risk profile were studied. CT angiography was performed using a Dual-Source CT scanner (330 ms rotation, 2 × 64 × 0.6 mm collimation, 60–80 mL contrast agent i.v. at 6 mL/s) before invasive catheterization. We analyzed plaque volume (mm 3), mean and minimal CT density (HU), remodeling index, plaque type (calcified/non-calcified/mixed) and presence of “spotty” calcifications as well as presence of contrast rims. Results In patients with ACS and SAP, 28 and 10 lesions showed both calcified and non-calcified components, but in a greater proportion of non-calcified material, 6 and 23 lesions showed a greater proportion of calcified material and 21 and 8 lesions were completely non-calcified, respectively. None of the culprit plaques in ACS and 14 of the lesions in SAP were completely calcified. A “spotty” pattern of calcification within the plaque and a central filling defect surrounded by a rim of contrast were present in 11 and 14 of 55 ACS cases, but never in SAP lesions. For culprit lesions in ACS and for lesions in patients with SAP, mean plaque volumes were 192.8 ± 114.9 mm 3 and 103.8 ± 51.8 mm 3 ( p = 0.001), mean and minimal CT densities were 85.6 ± 45.1 HU and 47.2 ± 33.7 HU versus 143.8 ± 104.1 HU and 95.9 ± 84.0 HU ( p < 0.01) and mean remodeling indices were 1.6 ± 0.4 and 0.97 ± 0.17 ( p < 0.001), respectively. Conclusion Plaques of culprit lesions in ACS show specific morphologic characteristics in non-invasive coronary CT angiography. As compared to stable lesions, culprit lesions in ACS display greater proportion of non-calcified material and presence of “spotty” calcifications/contrast rims as well as larger plaque volumes, lower CT attenuation and higher remodeling indices.