Low Contrast Dose and Low Tube Voltage Combined with Adaptive Iterative Reconstruction in Abdominal CT Angiography in Patients with Different BMI

Objective: To investigate the image quality and radiation doses resulting from abdominal CTA when using low concentration contrast combined with low kV. Methods: 90 patients from our hospital during 2017 Jan. to 2018 Jun. were chosen for our study. The patients were divided into two groups: Group A: normal doses (120kV, 370mgI/mL), Group B: low doses group (100kV, 270mgI/mL). Group A and Group B were subdivided into three subgroups according to their BMI: A1, B1 (BMI<24), A2, B2 (2428). 100mL contrast medium was injected at the speed of 4mL/s, after then, 20mL saline was added. The CT value and CNR of abdominal aorta, common hepatic artery, splenic artery, superior mesenteric artery and right renal artery, were evaluated by both doctors and system. The data were analyzed by SPSS16.0 software. Results: no significant difference were found in CT value or CNR of abdominal aorta, common hepatic artery, splenic artery, superior mesenteric artery and right renal artery (P>0.05). However, the radiation doses were much lower in low dose group compared with normal group (P<0.05). We also found a negative correlation between CNR and BMI value in low dose group, but not in normal group. Conclusion: There is no difference in image quality or CT value between normal group and low group. Radiation doses were significantly reduced in low doses group.