Reducing both radiation and contrast doses in coronary CT angiography in lean patients on a 16-cm wide-detector CT using 70kVp and ASiR-V algorithm, in comparison with the conventional 100-kVp protocol

ObjectiveTo investigate the value of prospectively ECG-triggered coronary CT angiography (CCTA) for lean patients with body mass index (BMI) 23kg/m(2) using 70kVp and high-level volume-based adaptive statistical iterative reconstruction (ASiR-V) algorithm on a 16-cm wide-detector CT system for reducing both radiation and contrast doses in comparison with the conventional 100-kVp protocol.Materials and methodsThirty patients (group A) were prospectively enrolled to undergo 70-kVp CCTA on a 16-cm wide-detector CT scanner with noise index (NI) of 36HU and at weight-dependent contrast dose rate of 16mg I/kg/s for 9-s injection. Images were reconstructed with 80% ASiR-V. Radiation dose, contrast dose, and image quality were statistically compared with 30 patients (group B) in database with matching BMI who underwent conventional 100-kVp CCTA with NI of 25HU, and at 25mg I/kg/s rate for 10-s injection and reconstructed with 60% ASiR-V.ResultsThere was no significant difference in patient demographics between the two groups (all p>0.05). The two groups also had similar mean CT values and contrast-noise ratio (CNR) and subjective image quality (all p>0.05). However, group A with 70kVp reduced the effective dose by 75.3% compared with group B (0.430.20mSv vs. 1.741.01mSv, p<0.001), and required 42.4% less contrast dose than group B (22.462.94ml vs. 38.995.10ml, p<0.001).ConclusionsProspectively ECG-triggered CCTA using 70kVp and high-level ASiR-V on a 16-cm wide-detector CT system provides diagnostic images with substantial reduction in both radiation and contrast doses for patients with BMI 23kg/m(2) compared to the conventional 100-kVp protocol.