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Use of low tube voltage and low contrast agent concentration yields good image quality for aortic CT angiography.
Wei, L, Li, S, Gao, Q, Liu, Y, Ma, X
Clinical radiology. 2016;(12):1313.e5-1313.e10
Abstract
AIM: To evaluate the impact of a "double-low" imaging protocol (low tube voltage and low contrast agent concentration) on image quality and radiation dose for aortic computed tomography (CT) angiography (CTA). MATERIALS AND METHODS This was a prospective study of 72 patients undergoing aortic CTA. They were randomised to the double-low and conventional CT (control) groups (n=36/group). Axial imaging was performed in the study group, and control patients were scanned with the conventional protocol. Double-low parameters were: 80-100 kV, 200 mAs, 128×0.625 collimation, 1-mm section thickness, 0.5-mm increments, 300 mm field of view (FOV), iohexol (300 mg iodine/ml, 1-1.5 ml/kg, injected at 4-5 ml/s). Control CT parameters were: 120 kV, 200-300 mAs, iopamidol (370 mg iodine/ml; 1-1.5 ml/kg, injected at 4-5 ml/s); the remaining parameters were the same as in the double-low group. RESULTS Image noise and quality scores of the double-low and control groups were 15.05±1.53 versus 14.67±1.53 and 3.52±0.51 versus 3.44±0.5 (both p>0.05), respectively. Radiation dose was 56% lower in the double-low group compared to control patients (6.76±1.08 versus 15.48±1.01 mSv, p<0.001). Iodine intake per-capita in the double-low group was 18% lower compared to the control group (300.25±7.2 versus 367.86±5.54 mgI/kg, p<0.001). CONCLUSIONS The "double-low" technique for aortic CTA significantly reduced the doses of radiation and iodine contrast agent, while maintaining good image quality.