Evaluation of Nitroglycerin Premedication on the Arterial Luminal Diameter and Branches of Coronary Arteries on 64-Multidetector Computed Tomography Angiography

Background The 64-multidetector computed tomography (64-MDCT) has developed into a mature clinical tool to detect coronary artery disease. This 64-MDCT system permits cross-sectional and longitudinal imaging of the coronary arteries with a high spatial and temporal resolution. However, small vessels, side branches and the distal portions of the main coronary arteries are not always optimally visualized. Purpose The aim of this study was to evaluate the effect of nitroglycerin (NTG) on lumen diameters and the number of visualized side branches of the coronary arteries on 64-MDCT. We also assessed whether NTG would affect the quality of the images of the coronary arteries obtained by 64-MDCT. Methods Sixty-seven patients were randomized and divided into two groups: Group C (31 patients, no sublingual NTG) and Group N (36 patients, sublingual NTG given before the scan). We measured the lumen diameter of the coronary artery and visibility of the side branches by using the 64-MDCT system and also evaluated the image quality by using the scores. Results The cardiac 64-MDCT images of these patients showed that the average diameters of the proximal segments in the right coronary artery, left main artery, left anterior descending coronary artery, and left circumflex coronary artery were 4.1 ± 0.7 mm, 3.9 ± 0.6 mm, 3.6 ± 0.7 mm, and 3.4 ± 0.6 mm, respectively, in Group N and 3.0 ± 0.5 mm, 3.1 ± 0.6 mm, 2.8 ± 0.5 mm, and 2.7 ± 0.5 mm, respectively in Group C. In addition, the scores for visibility and image quality for the side branches in Group N were significant higher than for those in Group C. Conclusion Our study indicates that CT coronary angiography using 64-MDCT with NTG administration produces images of diagnostically acceptable quality in all coronary segments. Thus, NTG might be recommended for routine 64-MDCT coronary angiography examinations.