Aortic root motion artifacts on non-electrocardiographic-gated chest CT: A comparison of five CT scanner protocols including an ultrafast wide-detector CT system

This study aimed to compare aortic root motion artifacts across 5 computed tomography (CT) scanner protocols on non-electrocardiographic-gated contrast-enhanced chest CT, with particular attention to a 256-detector-row wide-detector computed tomography (WDCT) scanner using an ultrafast scan mode. This single-center retrospective and prospective observational study included 321 patients (mean age: 63.9 ± 13.2 years; 167 men) who underwent contrast-enhanced chest CT on 5 CT scanners (CT1-5): CT1 (256-detector row); CT2/CT4/CT5 (64-detector row); and CT3 (320-detector row). Two radiologists scored motion-related subjective image quality at 4 aortic root anatomic sites (aortic valve, aortic sinus, coronary artery ostia, and ascending aorta) using a 3-point scale (0-2). In the prospective cohort, heart rate was recorded at scanning, and its association with subjective image quality was evaluated. Objective image quality was assessed using the signal-to-noise ratio (SNR) and the contrast-to-noise ratio of the ascending and descending aorta. Subjective image-quality scores differed according to anatomic site, with the ascending aorta showing the highest scores (P < .001). The 256-detector-row WDCT system with its routine ultrafast protocol (CT1) demonstrated the highest overall motion-related subjective image-quality score among the 5 CT scanner protocols (CT1-CT5: 1.60 ± 0.45, 1.31 ± 0.53, 0.52 ± 0.44, 0.23 ± 0.32, and 0.17 ± 0.22, respectively; P < .001). In the prospective cohort, heart rate was not significantly associated with subjective image quality (P = .981). Objective image quality (SNR and contrast-to-noise ratio) was highest in CT5 and lowest in CT2, whereas CT1 showed values comparable to those of CT3 and CT4 despite its ultrafast acquisition protocol. Among the 5 CT scanner protocols evaluated, the 256-detector-row WDCT protocol using an ultrafast scan mode achieved the highest motion-related subjective image quality for aortic root evaluation on non-electrocardiographic-gated chest CT without compromising objective image quality.