Clinical Evaluation of Radiation Dose Benefit and Image Quality of the Step-and-Shoot Technique Electrocardiogram-gated Coronary Computed Tomography Angiography

Full Article

GG Lo, JKF Chan, SK Yu, CW Lau, YF Leung

Hong Kong J Radiol 2008;11:81-4

Objective: To evaluate the radiation dose reduction benefit and image quality performance of SnapShot Pulse in step-and-shoot mode for helical coronary computed tomography angiography.

Methods: Twenty coronary computed tomography angiography scans using SnapShot Pulse in stepand- shoot mode were randomly selected. Only patients with heart rate less than 65 bpm were included. The image quality and radiation dose of the 20 scans were compared with those of 20 randomly selected coronary computed tomography angiography scans performed previously using the helical mode. All examinations were performed on the same computed tomography scanner using the standard injection protocol. Two radiologists were involved in the evaluation of image quality of each segment of the coronary arteries in a double-blind manner using a 4-point scoring system.

Results: There was no statistically significant difference in the image quality assessment between the 2 groups. The radiation dose was at least 3 times lower for SnapShot Pulse in stepand- shoot mode compared with that in helical mode.

Conclusion: Coronary computed tomography angiography using the SnapShot Pulse technique in step-and-shoot mode can confer a beneficial radiation dose reduction, while preserving the image quality, when compared with conventional helical mode.