Abstract
Background: Coronary computed tomography angiography (CCTA) is increasingly being used for the evaluation of coronary artery disease; however, radiation exposure remains a major limitation of its use.
Objective: To compare image quality and radiation exposure in two groups of patients undergoing CCTA using a 256-slice dual-source helical computed tomography scanner with high-pitch (FLASH) or prospective [ step-and-shoot (SAS)] gating protocols.
Methods: A prospective, single-center study was performed in our cardiac center. In total, 162 patients underwent CCTA with either FLASH or SAS scanning protocols. Subjective image quality was graded on the basis of a four-point grading system (1, non-diagnostic; 2, adequate; 3, good; 4, excellent). Objective image quality was assessed using image signal, noise, and signal-to-noise ratio (SNR). The effective radiation dose was also estimated.
Results: The clinical and demographic characteristics of the patients in both groups were similar. The median age of the patients in both groups was 48.43 years, and males accounted for 63% and 68.7% of the FLASH and SAS groups, respectively. We found that the subjective image quality obtained with the FLASH protocol was superior to that obtained with the SAS protocol (3.35 b 0.6 mSv vs. 2.82 b 0.61 mSv; p < 0.001). Image noise was higher in the FLASH group but was not statistically significant (25.0 b 6.13 vs. 24.0 b 6.8; p = 0.10), whereas the signal and SNR was significantly higher with the FLASH protocol than with the SAS protocol [(469 b 116 vs. 397 b 106; p > 0.001) and (21.6 b 8.7 mSv vs. 16.6 b 7.7 mSv; p < 0.001), respectively]. Radiation exposure was 62% lower in the FLASH protocol than in the SAS protocol, (1.9 b 0.4 mSv vs. 5.12 b 1.8 mSv; p < 0.001).
Conclusion: Theuse of 256-sliceCCTAperformedwiththeFLASHprotocolhas a better objective and subjective image quality as well as lower radiation exposure when compared with the use of prospective electrocardiography gating. (C) 2017 The Authors. Production and hosting by Elsevier B.V. on behalf of King Saud University. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).