Effect of bolus tracking region-of-interest position within the descending aorta on luminal enhancement of coronary arteries in coronary computed tomography angiography

To compare coronary artery luminal enhancement in coronary computed tomography angiography (CCTA) between ventral and dorsal region-of-interest (ROI) bolus tracking in the descending aorta. The records of 165 consecutive patients who underwent CCTA with non-helical acquisition from July 2017 to March 2018 were retrospectively examined. We performed 320-row CCTA with bolus tracking [scan triggered at 260 HU in the descending aorta] and 133 patients were finally included. ROI was set in the ventral and dorsal halves of the descending aorta in 68 and 65 patients, respectively. Contrast arrival time was significantly shorter in the dorsal group (ventral: 21.8 ± 0.372 s; dorsal: 20.7 ± 0.369; P = .0295). The mean density of the proximal and distal RCA was significantly higher in the ventral group (proximal: ventral, 428.1 ± 6.95 HU; dorsal, 405.5 ± 7.72 HU, P = .0318; distal: ventral, 418.0 ± 9.29 HU; dorsal, 393.2 ± 9.46 HU, P = .0133). Dorsal bolus tracking ROI in the descending thoracic aorta significantly reduced preparation time and RCA CT values.