Image Quality of 256-Slice Computed Tomography for Coronary Angiography.
OBJECTIVE
To assess the image quality of 256-slice computed tomographic angiography (CTA) and to identify possible impact factors associated with image quality.


METHODS
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.


RESULTS
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.


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


BACKGROUND
Coronary angiography; Heart rate; Image quality; Multi-slice computed tomography.
Division of Cardiology;
Shu-Ping
SP
Chao
Division of Nephrology;
Jyh-Gang
JG
Leu
Department of Diagnostic Radiology, Shin Kong Wu Ho-Su Memorial Hospital;
Wai-Yip
WY
Law
Department of Diagnostic Radiology, Shin Kong Wu Ho-Su Memorial Hospital;
Chu-Jen
CJ
Kuo
Division of Cardiology; ; Graduate Institute of Clinical Medicine, Taipei Medical University, Taipei, Taiwan.
Kou-Gi
KG
Shyu