Low-dose abdominal CT protocols with a tube voltage setting of 100 kVp or 80 kVp: Performance of radiation dose reduction and influence on visual contrast

• Performing abdominal CT with 80 kVp and 100 kVp setting enables radiation dose reductions compared with the 120 kVp setting with a similar CNR.
• CT images obtained using a 100 kVp tube voltage and optimized display settings displayed similar image contrast to those obtained at 120 kVp.
• Performing abdominal CT at 80 kVp resulted in altered visual contrast compared with the 120 kVp protocol.

AimTo evaluate the radiation dose, image quality, and influence on visual contrast of low tube voltage abdominal computed tomography (CT) and the effects of display setting optimization.Materials and methodsOne hundred and fifty-seven patients were randomly assigned to one of three protocols. Fifty-two patients underwent a 120 kVp protocol, and 53 and 52 patients underwent low-dose protocols with 100 and 80 kVp, respectively. The effective dose (ED), image noise, CT attenuation, and signal-to-noise ratio (SNR) of each organ of each protocol were compared using Dunnett's test. Qualitative analysis between the protocols was also performed.ResultsThe ED of the 100 and 80 kVp protocols were 22% and 37% reduced, respectively. There were no significant differences in the SNR between the protocols (120 kVp: 13.8 ± 3.5; 100 kVp: 13.9 ± 3.3; 80 kVp: 13.5 ± 2.9; p > 0.05). However, there were significant differences in contrast familiarity between the 120 kVp images and all the other images, except 100 kVp images, with optimized display settings (p < 0.05).ConclusionIn abdominal CT, an 80 kVp setting offers greater radiation dose reduction than a 100 kVp setting without significant deterioration of the SNR; however, the visual contrast between the organs might be changed.