Abstract：Objective To evaluate the application of Canon Genesis 640 slice CT variable pitch technique in ECG gated aorta vascular
imaging scans. Methods Patients undergoing aortic CTA were randomly divided into two groups using simple randomization
method: group 1 (n=31): scanning using the variable pitch technique, switchover of the three sections of pitch and the state of ECG
gating were done based on the need of different body parts. The first section: thoracic opening - tracheal bifurcation, pitch HP 91,
ECG-gating off. The second section: tracheal bifurcation - cardiac base, choose best pitch automatically according to heart rate, ECGgating
on. The third section: cardiac base- on the pubic symphysis, pitch HP 91, ECG-gating off. In group 2 (n=31), the conventional
spiral scan was used and best pitch was automatically selected according to the heart rate, with ECG-gating on. Two groups of
patients according to quality vein group lived 370 mgI/L Patients in both groups were intravenously injected with contrast agent at
the concentration of 370 mgI/L according to body mass. Group 1 was injected with contrast agent at 0.8 mL/kg according to body
mass at the injection rate of 4 mL/s, followed by 40 mL normal saline at the injection rate of 4 mL/s. In group 2, contrast agent was
injected at a rate of 4 mL/s according to the body mass of 1 mL/kg, followed by injection of 40 mL normal saline at a rate
of 4 mL/s. Automatic injection tracking trigger technique was used in both groups. The descending aorta of tracheal bifurcated
layer was selected to place the region of interest (ROI), and the scan was automatically triggered when the mean CT value in
ROI reached 180 HU. The dose length product (DLP), effective dose (ED), image signal-to-noise ratio (SNR) and contrast noise
ratio (CNR) of aortic vascular scan were calculated and evaluated objectively in both groups, and the image quality was evaluated
subjective. Results Group 1 scanning ED was (10.09±4.48) mSv, which decreased by 42% compared with group 2 (17.34±7.45) mSv
(t=4.638, P<0.001). There were no statistical differences in enhancement value, noise, SNR and CNR of renal artery in various parts
of the aorta (ascending aorta, aortic arch, origin of abdominal aorta, and bifurcation of abdominal aorta) and renal artery (P>0.05).
Image subjective evaluation between the two groups had no statistical significance. Conclusion In CTA scanning of aorta with ECT
gating technology, the application of variable pitch technology can not only guarantee image quality, but also significantly reduce
radiation dose and the amount of contrast agent.
徐凯，杜瑶，梁继祥，王沄，吴巧玲，孔令燕，付海鸿，金征宇. 可变螺距技术在主动脉血管成像中的应用价值[J]. 中国医疗设备, 2021, 36(9): 95-99.
XU Kai, DU Yao, LIANG Jixiang, WANG Yun, WU Qiaoling, KONG Lingyan, FU Haihong, JIN Zhengyu. Application Value of Variable Pitch Technique in Aortic Vascular Imaging. China Medical Devices, 2021, 36(9): 95-99.
