[Initial experience of 640-slice CT coronary angiography in pacemaker patients].

Objective: To investigate the feasibility and image quality of coronary artery angiography with 640-slice CT system in the pacemaker patients.

Methods: ECG-triggered 640-slice CT coronary angiography was performed in 16 pacemaker patients. Image quality of the fifteen coronary segments and metal-related artifact originating from pacemaker were assessed by two experienced radiologists in consensus. Image quality was assessed using a 4-point grading scale. ECG trigger information was recorded.

Results: The rate of available diagnostic images was 99.07% (Grade 1 in 83.64%, Grade 2 in 15.42%, Grade 3 in 0.47% and Grade 4 in 0.47% of patients, respectively). Image quality and the effect of streak artifact were similar between the high heart rate group and low heart rate group (P > 0.05) and between normal pacing group and arrhythmia group (P > 0.05). In coronary MSCT angiography, streak artifact of the pacemaker can render segments of the coronary artery uninterpretable, especially on S1, S2, S3, S4 and S8 segments of the coronary artery. Small shifts in the reconstruction window resulted in significance reduction of streak artifact (χ(2) = 151.818, P < 0.01).

Conclusions: 640-slice gated CT coronary angiography could provide excellent image quality for patients with pacemaker. The streak artifact induced by pacemaker on some segments of the coronary artery could be improved by small shifts in the reconstruction window.