Fig. 1

Coronary artery segments: (1) proximal segment of right coronary artery (RCA); (2) middle segment of RCA; (3) distal segment of RCA; (4) right posterolateral artery; (5) posterior descending artery; (6) left main coronary artery; (7) proximal segment of left anterior descending artery (LAD); (8) middle segment of LAD; (9) distal segment of LAD; 10.first diagonal branch; (11) second diagonal branch; (12) proximal segment of left circumflex (LCX); 13. distal segment of LCX; (14) first obtuse marginal branch; (15) second obtuse marginal branch; (16) left posterolateral artery. In this example, plaque distribute on proximal segment of RCA, proximal segment of LAD and proximal segment of LCX respectively. Segment involvement score was calculated by summation of the involved number of coronary segments. The segment involvement score in this example is 3 out of a possible 16. Segment stenosis score was calculated by summation of minimal plaque in the proximal RCA (scored 1), mild plaque in the proximal LAD (scored 2) and severe plaque in the proximal LCX (scored 4).The segment stenosis score is 7 out of a possible 80