Image Quality of 256-Slice Computed Tomography for Coronary Angiography

To assess the image quality of 256-slice computed tomographic angiography (CTA) and to identify possible impact factors associated with image quality.

From November 2009 to January 2010, 506 patients underwent 256-slice CTA at our institute. A total of 451 patients were enrolled in our study, after 55 patients were excluded because of prior bypass surgery and stenting. CTA image quality was graded by two observers using a 4-point scale: excellent (score 1), good (score 2), moderate (score 3), poor and non-diagnostic (score 4). The coronary arteries were divided into 15 segments. Image quality was correlated to the subjects' age, gender, body mass index, heart rate, and calcium scores.

We evaluated 6650 coronary segments from CTA images of our enrolled 451 patients. The mean image quality score of all coronary segments was 1.14. Most coronary segments (99.7%) were assessable, and only 21 segments (0.3%) were non-diagnostic. A total of 5824 coronary segments were classified as having excellent image quality. Forty-two patients (9.3%) required control of heart rate with beta-blockers before CTA could be performed. Male patients had better image quality than female patients. Heart rate and severity of calcification were impact factors associated with image quality.

Examination with 256-slice CTA provides good image quality and can effectively evaluate most coronary segments.

Coronary angiography; Heart rate; Image quality; Multi-slice computed tomography.