Single-Bolus Sequential Triple-Rule-Out CT Angiography: Image Quality and Radiation Dose on Wide-Area Detector and Dual-Source CT

Background/Objectives: Single-pass triple-rule-out computed tomography (CT) angiography (TRO-CTA) must compromise among differing pulmonary, coronary, and aortic contrast-transit times. Wide-area detector CT (WAD-CT) and dual-source CT (DSCT) offer different coverage, temporal resolution, and dose profiles, but direct comparative evidence for a sequential single-bolus strategy is limited in selected emergency patients with overlapping concern for acute coronary syndrome, pulmonary embolism, or acute aortic syndrome. We compared territory-specific image quality and radiation dose; diagnostic accuracy was not assessed. Methods: This retrospective study included 114 adults (WAD-CT, n = 60; DSCT, n = 54). After test-bolus timing, one weight-based diagnostic bolus was used for sequential pulmonary, electrocardiography-synchronized coronary, and non-gated aortic acquisitions. Attenuation, noise, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), blinded dual-reader quality scores, and radiation dose were compared by territory. Results: Mean overall scores across the two readers were ≥3 for every examination in all phases. WAD-CT showed higher pulmonary trunk SNR (19.5 ± 8.9 vs. 14.3 ± 3.8; p = 0.002), higher ascending aortic SNR (24.9 ± 11.4 vs. 14.2 ± 3.0; p < 0.001), lower coronary and aortic noise, and 38.1% lower total estimated dose (6.40 ± 1.72 vs. 10.34 ± 6.91 mSv; p < 0.001). DSCT showed higher right coronary attenuation (671.8 ± 186.7 vs. 466.4 ± 128.9 Hounsfield units; p < 0.001), no significant difference in right coronary SNR (p = 0.681), and less aortic-root pulsation artifact (p < 0.001). Pulmonary- and coronary-phase overall scores were comparable. Conclusions: Both protocols provided acceptable territory-level image quality from one diagnostic bolus. WAD-CT provided lower coronary and aortic noise and estimated radiation dose, whereas DSCT provided higher coronary attenuation and less aortic-root pulsation artifact. Diagnostic accuracy and performance in subsegmental pulmonary arteries and distal or small coronary branches remain unestablished.