Cardiac computed tomography and image analysis

All patients underwent a CCT with a third-generation dual source multidetector computed tomography scanner (Somatom Force, Siemens Healthcare AG, Germany). Details on the imaging protocols are given in the S1 Appendix. CCT derived parameters such as CACS, stenosis degree (in percentage of lumen reduction), non-calcified plaque volume (NCPV), calcified plaque volume (CPV), total plaque volume (TPV) and PB were calculated as previously reported [34]. Plaque segmentations were performed by two independent technicians and averaged values for each derived imaging parameter were considered. Only three patients showed multivessel CHD at CCT for whom the most significant plaque was considered for the segmentation and statistical analysis. All scans were analyzed by 2 experienced radiologists. After independent evaluations were made, a consensus interpretation was achieved according to the international SCCT guidelines [35]. Patients were grouped according to imaging parameters. Two representative examples of plaque segmentation by CCT to calculate imaging parameters are reported in Fig 1 and Fig 2.

(A) 3D volume rendering and (B) Curved multi planar reconstruction of a left anterior descending artery showing a proximal mostly non-calcified plaque with a spotty calcification (white arrow in (A) and (B) panels) and a distal calcified plaque. Semi-automatic segmentation of coronary vessel: calcified component (yellow), lipid component (green) and fibrotic (blue).

(A) Curved multi planar reconstruction of a right coronary artery showing a severe atherosclerosis with both calcified and non-calcified plaques. (B) Semi-automatic segmentation of coronary vessel: calcified component (yellow), lipid component (green) and fibrotic (blue).