Reduction of the Body Weight-adapted Volume of Contrast Material by Increasing the Injection Rate in 320-detector Row Coronary CT Angiography

Abstract

Background: 320-detector row dynamic volume computed tomography (CT) scanner was widely applied in coronary CT angiography (CCTA)，which made it possible to reduce the volume of contrast material (CM) used. Some studies have reported the feasibility of reducing the CM in 320-detector row CCTA using a weight-adapted injection protocol. However, it hasn't been studied to investigate what was the significance of increasing the injection rate with a lower volume of CM. Objective: To investigate the feasibility of reducing the body weight-adapted volume of CM by increasing the injection rate in 320-detector row CCTA. Methods: A total of 116 patients who underwent 320-detector row CCTA were divided into three groups. Group A received 0.7 ml/kg of CM (350 mg I/ml) at an injection rate of 5.0 ml/s (n = 40); group B received 0.6 ml/kg of CM at 5.5 ml/s (n = 39); group C received 0.5 ml/kg of CM at 6.0 ml/s (n = 37). A 30-ml 0.9% saline chaser was administered after the CM. Enhancement values of the cardiovascular territories and coronary arteries were measured and compared. Image quality was also evaluated and compared among the three groups. Result: Enhancement values of the proximal coronary arterial segments for group C were significantly lower than those for groups A and B (all, P < 0.05), whereas there were no significant differences between groups A and B (all, P > 0.05). Similar statistical results were found in the proportion of proximal coronary arterial segments with enhancement values ≥ 300 HU, image quality ratings and the proportion of the main of coronary arterial segments with image quality scores ≥ 3 on both per-vessel and per-patient analyses. Conclusion: At least 0.6 ml/kg with 350 mg I/ml of CM at 5.5 ml/s injection rate was required to achieve sufficient and credible evaluation of the coronary artery in 320-detector row CCTA.