Author(s)

Haidong Chen, Zhenjie Yu, Rungen Zhan, Weicheng Lin, Rong Zhou, Jiamin Li^*

Affiliation(s)

Department of Radiology, Zhuhai People's Hospital (Zhuhai Hospital affiliated with Jinan University), Zhuhai, 519000, P.R. China.

Corresponding Author

Jiamin Li

ABSTRACT

Objective: To improve the distal aortic image quality and reduce the whole radiation dose of high-pitch dual-source CT angiography using individual dose of contrast agent. Material and Methods: A total of 91 consecutive patients undergoing clinically indicated CT angiography (CTA) of the thoracoabdominal aorta on a dual-source scanner using either conventional dual-source CT angiography mode (n=47) or high-pitch dual-source CT angiography mode (n =44) during the arterial phase. For the high-pitch group, the delayed imaging time was the peak time of the femoral artery. The dose of contrast agent, contrast enhancement and signal noise ratio (SNR) were evaluated objectively. Subjective rating of the image quality throughout the thoracoabdominal aorta was assessed by two independent readers. Scanner-reported dose-length product values were used to estimate effective dose values. Results: Compared to conventional method, dual-source high-pitch aortic CT angiography dramatically shortened the total examination time by 78％ to 1.47±0.14 min. In the conventional group, there were 5 patients who had poor imaging of the distal arteries due to abdominal aortic aneurysm, so they needed additional re-scan. However, in the high-pitch group, all patients could obtain good images that meet the diagnosis requirements with only one scan. The mean dose of contrast agent decreased by 21.6% to 62.68±5.98 ml(P<0.001) in high-pitch group. Furthermore, the volume CT dose index, dose-length product and effective dose in high-pitch group were significantly lower than those in conventional group, reduced by 70.3%, 66.8% and 66.1% respectively (all P < 0.001). At the level of abdominal aorta, mean CT values, SNR and subjective rating were higher in high-pitch group compared to conventional group (all P < 0.05), whereas at the level of aortic root, there was no significant difference of SNR between two groups(P>0.05), the incidence of aortic root motion artifacts in the high-pitch group was significantly lower than that in the conventional group(P<0.05), and subjective rating was still much higher in high-pitch group than that in conventional group(P<0.05). Conclusion: High-pitch dual-source CT angiography using individual dose of contrast agent can not only effectively reduce the effective radiation dose, but also improve the image quality of the aortic root and distal end.

KEYWORDS

Dual-source CT, High-pitch, CT angiography, Aorta, individual dose of contrast agent

CITE THIS PAPER

Haidong Chen, Zhenjie Yu, Rungen Zhan, Weicheng Lin, Rong Zhou, Jiamin Li. Optimization of image quality and radiation dose via high-pitch aortic CT angiography with individual dose of contrast agent. Acta Translational Medicine. 2020, 3(1): 52-57.

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