RESUMEN
<p><b>OBJECTIVE</b>To observe the coronary vessel lumen diameter and bifurcation angle in subjects with normal CT coronary angiography (CTCA) imaging.</p><p><b>METHODS</b>64-row CT coronary angiography imaging from 526 adult people with excellent image quality and normal vascular image were analyzed in this study. The lumen diameter from the origin to distal with 2 mm lumen of left main coronary artery (LM), anterior descending branch (LAD), left circumflex branch (LCX) and right coronary artery (RCA) was measured at 1 cm interval in CPR image. The vascular tapered ratio was calculated. The bifurcation angle in the diagonal branch, obtuse marginal branch, posterior descending branch, acute marginal branch as well as the origin diameter was also measured in VR image.</p><p><b>RESULTS</b>The LAD average length was 13 cm and lumen diameter was 3.92 mm at origin and 2.10 mm at distal. The average decremented ratio of LAD was 7.7% (male 7.0%, female 8.4%). The maximal decremented ratio 8.0% - 10.0% occurred at 3 - 5 cm apart from the origin of LAD. The LCX average length was 13 cm and lumen diameter was 3.57 mm at origin and 2.10 mm at distal. The average decremented ratio of LCX was 9.7% (male 9.6%, female 9.7%). Lumen decremented ratio was less than 3.0% between origin and proximal 3 cm and 8.3% - 10.7% in the rest portion of the LCX. The RCA average length was 18 cm and lumen diameter was 3.97 mm at origin and 2.15 mm at distal. The average decremented ratio of RCA was 5.1% (male 4.9%, female 5.3%). The decremented ratio of RCR was less than 4.0% between origin and proximal 10 cm and 6.1% - 15.2% in the rest portion. The bifurcation angle was 50, 55, 66 and 76 degree for LAD with diagonal branch, LCX with obtuse marginal branch, RCA with posterior descending branch and RCA with obtuse marginal branch respectively.</p><p><b>CONCLUSION</b>Coronary artery length, lumen diameter and decremented ratio as well as bifurcation angel could be identified in 64 row CTCA image in vivo. This information could help us to understand the in vivo coronary artery anatomy.</p>