前瞻性心电门控技术在CT肺动脉血管成像中的应用

目的：研究256层螺旋CT前瞻性心电门控技术在肺动脉血管成像（CTPA）中的应用价值。方法：连续选取本院使用Philips 256层螺旋CT行CTPA检查的患者资料90例,利用完全随机设计每组30例分为3组：①非心电门控螺旋扫描组（简称非门控组）;②前瞻性心电门控组（简称前瞻组）;③回顾性心电门控组（简称回顾组）。记录各组患者年龄、性别、心率、扫描时间、扫描范围、容积CT剂量指数（CTDIvol）、剂量长度乘积（DLP）,根据公式计算出有效放射剂量（ED）。由3位有经验的放射科医生以双盲法对肺动脉图像质量进行评分,并评价在扫描范围内的冠状动脉运动伪影。结果：三组95.6%（86/90）的病例评分≥3分。图像质量评分、冠状动脉运动伪影出现率、扫描时间、辐射剂量差异有显著性意义。图像评分：前瞻组明显优于非门控组,与回顾组相近;冠状动脉运动伪影出现率：三组分别为88.1%、21.5%和15.9%,前瞻组和回顾组明显低于非门控组;辐射剂量：前瞻组和非门控组的辐射剂量分别为（7.59±0.87）和（7.49±0.80）mSv,两者差异无显著性意义,明显低于回顾组辐射剂量[（18.96±1.60）mSv];扫描时间：前瞻组平均扫描时间为（8.66±0.86）s,比回顾组和非门控组分别增加1.0s和5.5s。不同心率患者前瞻性心电门控CTPA的图像质量评分差异无显著性意义。结论：应用256层螺旋CT前瞻性心电门控技术行CTPA检查是一种可行方法,在不增加患者辐射剂量的前提下,明显改善肺动脉图像质量。

The application of prospective ECG-gated technique in CT pulmonary angiography

Objective：To study the application value of the prospective ECG-gated 256-slice spiral CT in pulmonary angiography.Methods：90 cases having undergone CTPA on Philips 256-slice spiral CT from July to December 2009 in our hospital were selected and divided randomly into three groups （30 cases each）：non ECG-gated helical scan group （non-gated group）;prospective ECG-gated group （prospective group）;retrospective ECG-gated group （retrospective group）.Scan time, scan length,CTDIvol and DLP of each group,together with the patients′ age,gender and heart rate were recorded and computed for an effective radiation dose （ED）.Three radiologists with experience estimated the scoring of image quality by double blind method and the coronary artery motion artifacts in scanning range.Results：The scoring of 95.6% of the cases （86/90） in these three groups was greater than or equal to 3.The scoring of image quality,the frequency of the coronary artery motion artifacts,scan time and radiation dose of three groups were significantly different.The scoring of image：the scoring of non-gated group was significantly lower than that of prospective group,equivalent to retrospective group.Coronary motion artifacts：three groups were respectively 88.1%,21.5% and 15.9%.Prospective and retrospective groups were significantly lower than non-gated group.Radiation dose：（7.59＋0.87）mSv for prospective group,（7.49＋0.80）mSv for non-gated group,having no significant difference but obviously lower than the dose of retrospective group （18.96＋1.60）mSv.Scan time：compared with retrospective and non-gated group,the mean scan time of prospective group which was （8.66＋0.86）s increased 1 and 5.5 second respectively.Different heart rates didn＇t influence the image quality of prospective ECG-gated CT pulmonary angiography obviously.Conclusion：Prospective ECG-gated technique on 256-slice spiral CT is a practicable method in performing CT pulmonary angiography,which can improve the image quality in the case of not increasing the radiation dose of patients obviously.