Abstract：Objective: To compare the image quality, radiation dose, and contrast dose of prospective ECG-gated sequence and large-pitch helical scan coronary imaging in patients of low heart rate in the third-generation dual-source CT. Materials and Methods: We prospectively collected 64 patients with coronary heart disease who underwent coronary CTA examination with heart rate less than or equal to 60 beats/min, and randomly divided these patients into groups A and B. Thirty patients in group A scanned with prospective ECG gating, using “step-point shot” combined with ECG trigger technology, and 34 patients in group B underwent large pitch spiral scan with the pitch of 3.2. Objective indicators for image quality evaluation include measurement of aortic root, left main trunk, proximal left anterior descending artery, proximal left circumflex artery, proximal coronary artery by enhanced CT values, signal-to-noise ratio(SNR), and contrast-to-noise ratio(CNR). 4-point methodwas used for subjective scoring of vascular segments. The effective radiation agent(ED) and contrast dose were recorded in 2 groups of patients. The objective indicators, radiation dose and contrast dose difference between the two groups were compared by t test. The difference of subjective score between the two groups was evaluated by χ2 test. Results: There were no significant differences in the CT values, SNR and CNR between the two groups(P>0.05). Among the 896 coronary arteries, 97.6%(409/419) in group A and 100%(477/477) in group B met the diagnostic request. 2.4%(10/419) in group A couldn’t meet the diagnosis request. Subjective scores of the two groups were statistically significant(P<0.01). The average radiation dose((0.62±0.19) mSv) of group B was reduced by 62.65% compared with group A((1.66±0.91) mSv); the contrast dose of group B((37.76±4.34) mL) was reduced by 25.82% compared with group A((50.90±9.51) mL). Both the radiation dose and contrast dose between group A and group B were statistically significant(P<0.01). Conclusion: For patients with heart rate ≤60 beats/min, the third-generation dual-source CT large-pitch spiral scan can provide sufficient diagnostic information for coronary examination and can significantly reduce radiation dose and contrast dose.
丁 毅，宋 彬，孙熙临，王 浩，林继先，罗运贺，徐晶晶. 第三代双源CT大螺距扫描冠脉成像在低心率患者中的应用分析[J]. 中国临床医学影像杂志, 2019, 30(11): 789-794.
DING Yi, SONG Bin, SUN Xi-lin, WANG Hao, LIN Ji-xian, LUO Yun-he, XU Jing-jing. High-pitch coronary CTA using the third-generation dual-source
CT: initial experience in patients with low heart rate. JOURNAL OF CHINA MEDICAL IMAGING, 2019, 30(11): 789-794.
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