320排容积CT三种心电扫描模式在胸腹主动脉CTA中的应用

目的探讨320排容积CT胸腹主动脉成像（CT angiography，CTA）在三种心电扫描模式下的图像质量及辐射剂量，为患者提供个性化扫描方案。方法183例疑似主动脉疾病患者随机分为三组。采用前瞻Wide-Volume扫描（A组）；前瞻性心电门控螺旋扫描（B组）；VHP扫描（可变螺距螺旋扫描）（C组）。每组再根据心率分成两个亚组，亚组1心率〉70次／min，亚组2心率〈70次／min。获得的6组图像数据分别进行图像处理，由2名有经验的放射科医师评价图像质量并进行统计学分析。结果183例患者全部获得满意图像质量。三组中，前瞻性心电门控螺旋扫描获图像质量最佳（主动脉评分-x=1．04分；冠状动脉评分-x=1．18分），辐射剂量最低（-x=13．62mSv），在低心率组（〈70次／rain）扫描时间最短（-x=14．1s）；前瞻Wide-Volume扫描在高心率组（〉70次／min）扫描时间最短（-x=14．5s）；VHP扫描辐射剂量最高（-x=24．04mSv）。各组间对比剂用量差异无统计学意义（A组-x=78．1ml；B组-x=79．6ml；C组-x=80．2ml，P〉O．05）。结论前瞻性心电门控螺旋扫描适用较低心率患者（心率〈70次／min），前瞻Wide-Volume扫描适用于较高心率患者（心率〉70次／min），VHP扫描辐射剂量较高，对比前两种方法无明显优势。

Application of the aorta 320-MDCT Angiography using three ECG-gating scanning models

Objective To evaluate image quality and radiation dose using three types of ECG-gating mode of 320 - MDCT in the aortic angiography examination so as to provide personalized scanning solutions for patients. Methods 183 patients with suspected aortic disease were randomly divided into three groups： prospective ECG-gating wide-volume scanning （group A）, prospective ECG-gating spiral scanning （group 13）, and Variable Helical pitch scanning （ group C）. Accord- ing to the heart rate of patient, each group was divided into two subgroups, and group 1, heart rate 〉 70 bpm, and group 2, heart rate 〈70 bpm. 6 seg of image data were for image processing. Two experienced radiologists performed image quality evaluation and statistical analysis. Results Al1183 patients got the satisfied quality of image. In the three groups, the image quality was the best using prospective ECG-gating spiral scanning model （Aortic score-x=1.04; Coronary artery -x= 1.18）, radiation dose was the lowest （ -x= 13.62 mSv）, and scanning time was the shortest in low heart rate group （ -x= 14. ls）. In high heart rate subgroup, the scanning time was the shortest using prospective wide-volume scanning （ x = 14.5s）. Variable Helical pitch scanning radiation dose the highest （ -x=24.04 mSv）. Each group contrast agent differ- ence was not statistically significant （group A-x=78.1 ml; group B-x=79.6 ml; C group-x= 80.2 ml, P 〉0.05）. Con- clusion Prospective ECG-gating spiral scanning model is suitable for patients with heart rate 〈70 bpm, prospective ECG- gating wide-volume scanning is applicable to patients with heart rate 〉70 bpm. Variable Helical pitch scanning radiation dose is higher compared to two other methods, which has no obvious advantage.