Image quality and radiation dose of low-tube-voltage CT with reduced contrast media for right adrenal vein imaging

Objectives To compare image quality and radiation dose of right adrenal vein (RAV) imaging computed tomography (CT) among conventional, low kV, and low kV with reduced contrast medium protocols. Methods One-hundred-and-twenty patients undergoing adrenal CT were randomly assigned to one of three protocols: contrast dose of 600 mgI/kg at 120-kV tube voltage setting (600-120 group), 600 mgI/kg at 80 kV (600-80 group), and 360 mgI/kg at 80 kV (360-80 group). Iterative reconstruction was used for 80-kV groups. Signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of the RAV and size-specific dose estimates (SSDE) were measured. Three radiologists evaluated 4-point visualisation scores of RAV by consensus reading. Results The RAV detectability was 95%, 97.2%, and 97.3% for 600-120, 600-80, and 360-80 groups, respectively (p = 1.000). Visualisation scores were not significantly different among the groups (p = 0.152). There were no significant differences in CNR or SNR between the 600-120 and 360-80 groups. SSDE of the 360-80 group was significantly lower than that of the 600-120 group (5.86 mGy ± 1.44 vs. 7.27 mGy ± 1.81, p < 0.001). Conclusions 80-kV scans with 360 mgI/kg contrast media showed comparable detectability of RAV to conventional scans, while reducing 19% of SSDE.