Non-Electrocardiogram-Triggered 70-kVp High-Pitch Computed Tomography Angiography of the Whole Aorta With Iterative Reconstruction: Initial Results.

Abstract

To evaluate the feasibility of non-electrocardiogram (ECG)-triggered 70-kVp high-pitch aortic computed tomography angiography (CTA) with iterative reconstruction (IR) and reduced contrast agent using second-generation dual-source CT (DSCT). Seventy-seven patients were examined: group A (n = 21), 70-kVp high-pitch (3.2) CTA, 60 mL contrast agent and IR on second-generation DSCT; group B (n = 29), standard-pitch (1.2) CTA, automatic tube voltage selection, filtered back projection and 80 mL contrast agent on second-generation DSCT; group C (n = 27), 120-kVp standard-pitch (1.2) CTA, filtered back projection, and 80 mL contrast agent on first-generation DSCT. Computed tomography values, noise, signal-to-noise ratio, contrast-to-noise ratio, and subjective image quality were compared. Computed tomography values and noise of all aortic segments in group A were increased compared with groups B and C (P < 0.05). Group B showed the highest signal-to-noise ratio and contrast-to-noise ratio for all aortic segments (P < 0.05), whereas no significant differences were found between groups A and C (P > 0.05). Mean effective dose was 0.88 ± 0.08 mSv for group A, reduced by 93% compared to group C and by 90% compared to group B. Non-ECG-triggered 70-kVp high-pitch aortic CTA with IR provides equivalent diagnostic image quality with 90% reduction of radiation dose and 25% reduction of contrast volume compared with standard 120-kVp CTA.