One-stop head-neck and coronary CT angiography: impact of high-concentration contrast media and low tube voltage on image quality and radiation dose

Objective To evaluate the combination of high-concentration contrast media (CM) and low tube voltage can reduce radiation dose in one-stop head-neck CT angiography (HNCTA) and coronary CTA (CCTA) without compromising image quality. Methods Patients with or suspected atherosclerosis randomly assigned to four groups. Group A and B underwent conventional-dose (CD) protocols with 320 mg I/ml and 100 kV (HNCTA). Groups C and D underwent low-dose (LD) protocols using 400 mg I/ml and 80 kV (HNCTA). Group A and C with heart-to-cranial sequence, Group B and D with cranial-to-heart sequence. Subjective image quality was independently evaluated by two radiologists. The objective image quality and effective dose (ED) were compared. Results The group D achieved the highest scores on per-patient for one-stop CTA. The LD groups demonstrated comparable background noise, signal-to-noise-ratio (SNR), contrast-to-noise-ratio (CNR) in HNCTA. For CCTA, the LD groups exhibited lower background noise (all p < 0.05). Group C showed higher SNR and CNR in all coronary branches compared to group A ( p < 0.05), except in the aortic root ( p > 0.05). For radiation dose, the group D had the lowest ED (4.13 ± 0.63 mSv, p < 0.001). Conclusion The combination of 80 kV and 400 mg I/ml CM enables effective imaging of the one-stop CTA. The cranial-to-heart sequence in LD protocol may further reduce radiation dose without compromising image quality.