Use of low tube voltage and low contrast agent concentration yields good image quality for aortic CT angiography.
OBJECTIVE
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).


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.
Department of Radiology, Qilu Hospital of Shandong University, Wenhua West Road No. 107, Jinan, 250012, Shandong, People's Republic of China; Department of Radiology, Liaocheng City People's Hospital, Dongchang West Road No. 67, Liaocheng 252000, Shandong, People's Republic of China.
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L
Wei
Department of Radiology, Liaocheng City People's Hospital, Dongchang West Road No. 67, Liaocheng 252000, Shandong, People's Republic of China.
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S
Li
Department of Radiology, Liaocheng City People's Hospital, Dongchang West Road No. 67, Liaocheng 252000, Shandong, People's Republic of China.
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Q
Gao
Department of Radiology, Liaocheng Dongchangfu People's Hospital, Dongguan Street No. 281, Liaocheng 252000, Shandong, People's Republic of China.
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Y
Liu
Department of Radiology, Qilu Hospital of Shandong University, Wenhua West Road No. 107, Jinan, 250012, Shandong, People's Republic of China. Electronic address: 1365608242@qq.com.
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Ma
D000368:Aged; D001011:Aorta / Q000000981:diagnostic imaging; D000072226:Computed Tomography Angiography / Q000379:methods*; D003287:Contrast Media; D017023:Coronary Angiography / Q000379:methods*; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D007472:Iohexol; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011829:Radiation Dosage; D011856:Radiographic Image Enhancement; D059629:Signal-To-Noise Ratio
D003287:Contrast Media; D007472:Iohexol