Coronary CT angiography with 64-MDCT: Assessment of vessel visibility

OBJECTIVE. The objective of our study was to evaluate the image quality of 64-MDCT for coronary angiography. SUBJECTS AND METHODS. Fifty consecutive CT coronary angiograms obtained on a 64-MDCT scanner were independently reviewed by two reviewers. Segments were scored as showing no motion (score of 1), minimal motion (2), moderate motion (3), respiratory motion (4), or vessel blurring (5). Opacification was graded as good (score of 1) or limited (2). Segments < 2 mm were graded as well seen; or as poorly seen or not seen. The scores for motion artifact, opacification, and visibility were combined for overall vessel assessment. Segments with a motion score of 1 or 2 that had good opacification and were well seen were judged to be assessable. RESULTS. A total of 714 segments were analyzed in 50 patients. Seven hundred segments were assessed in all patients (segments 1-3, 11-20, 4, or 27), and a ramus intermedius segment was evaluated in 14 patients. Combining the scores for both reviewers, the average motion score was 1 for 619 segments (86.7%), the average motion score for all segments in an individual patient was 1.14 (range, 1-3.35), and the average Opacification score for all segments in a patient was 1.02 (range, 1-1.38). A total of 374 segments were less than 2 mm in diameter. Combining the scores for both reviewers, an average of 36 segments (5.0% of 714) could not be identified by the reviewers, 319.5 segments (85.4%) were well seen, and 18.5 segments (4.9%) were poorly seen. Overall, an average of 637 segments (89.2%) were judged assessable by the reviewers. On a perpatient basis, 10 or more vessel segments were judged assessable in 47 patients (94%). CONCLUSION. On 64-MDCT, 89% of coronary artery segments are assessable. Ten or more vessel segments are assessable in 94% of patients.