Abstract
BACKGROUND: Aortic computed tomography (CT) angiography (ACTA) is a key noninvasive tool for assessing aortic diseases, which typically requires high tube voltage and large volumes of contrast agent, thus potentially increasing radiation exposure and the risk of contrast agent-induced nephropathy. This study aimed to explore the effect of three-low technique (low tube voltage, low contrast agent injection rate, and low contrast agent volume) in CTA for patients with a body mass index (BMI) <30 kg/m(2), thus this technique may be used as an alternative to conventional ACTA. METHODS: Eighty patients with a BMI less than 30 kg/m(2) undergoing CTA examination with a Philips iCT 256-slice scanner were randomly assigned into two groups according to the examination technique used: three-low group (n=40): tube voltage: 100 kV, contrast agent injection rate: 3 mL/s, contrast agent volume: 50 mL; control group (n=40): tube voltage: 120 kV, injection rate: 5 mL/s, contrast agent: 80 mL. Aortic CT value and image noise were detected, the signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were computed, and the subjective score of the image quality was evaluated. The effective radiation dose was computed according to a formula. RESULTS: Compared with the control group, the effective radiation dose was decreased by 76.2% (10.32±0.46 vs. 2.46±0.71 mSv), while the aortic CT value was increased by approximately 13% (360.14±56.52 vs. 402.12±88.34 HU), the image noise (22.23±5.34 vs. 13.32±3.54) was higher, while the contrast agent volume (80 vs. 50 mL), SNR (24.2±7.4 vs. 20.6±6.1) and CNR (22.4±6.5 vs. 18.3±6.2) were lower in the three-low group, and all these differences between the two groups were statistically significant (all P<0.05). There was no statistically significant difference in the subjective score of image quality (4.4±0.8 vs. 4.2±0.9) between the two groups (P>0.05). CONCLUSIONS: Three-low technique has a good application value in CTA for patients with a BMI of lower than 30 kg/m(2); the effective radiation dose was decreased by 76.2%, the contrast agent volume was decreased by 37.5%, and all images met the diagnostic requirements.