ECG电流调控技术对64MDCT冠状动脉成像质量和放射剂量的影响及评估  

Evaluation of electrocardiograph modulated milliampere with 64-row multidetector CT on image quality and exposure dosage in coronary artery imaging

作　　者：高建华[1] 王贵生[1] 李剑颖[2] 孙宪昶[1] 扬帆[1] 戴汝平 

机构地区：[1]武警总医院CT室,北京100039 [2]GE中国CT影像研究室,北京100176 [3]阜外医院放射科,北京100037

出　　处：《医学影像学杂志》2007年第10期1095-1098,共4页Journal of Medical Imaging

摘　　要：目的：通过开启或关闭ECG（心电图）电流（mA）调控对图像质量和放射剂量影响的对照研究，评估ECG电流调控技术对降低64MDCT成像放射剂量的作用和价值。方法：按照统一的纳入标准，连续选取100例患者（男54例，女46例，年龄36—80岁，平均58．9岁），使用GEu出speed VCT机完成冠状动脉检查。将病人分为NE、UE两组，每组50例。两组在性别比例、年龄、身高、体重及心率五个方面无显著性差异（P〉0．05）。NE组扫描时关闭ECG电流调控，UE组扫描时开启ECG电流调控。其它扫描参数相同：120kV，0．35s／r，层厚0．625mm，Pitch 0．20—0．26，Bowtie选用large body,模式。①以双盲法对两组图像从冠脉节段的显示数目、细小分支显示率、血管边缘锐利度、血管内对比剂清晰度四个方面以1—4分（4分为优）进行图像质量评分。评分有分歧的由两人共同商讨后达成一致；②分别选取两组图像中面积相等的感兴趣区（砌，面积为100mm^2），在相同轴位图像上（均为左冠状动脉主干自左窦发出的层面）测量升主动脉中心部的噪声值（均值及标准差），比较NE组和UE组图像噪声差异；③记录关闭或开启ECG电流调控扫描产生的容积CT剂量指数（CTDI-vol）和剂量长度乘积（DLP），根据ED=DIP×C公式换算成有效剂量（ED）。其中C采用European Guidelines on Quality Crite．ria for Computed Tomograpgy提出的胸部平均值0．017；④应用SPSS10．0软件对NE组和UE组间图像质量评分、图像噪声、CTDIvol、ED均值差异进行t检验，P〈0．05为有统计学意义。结果：①NE组、UE组图像质量评分分别为（3．56±0．54）分、（3．68±0．47）分，P〉0．05，两组间无显著性差异；②NE组、UE组图像噪声分别为27．54±4．52、28．09±4．85，P〉0．05，两组间无显著性差异；③NE组、UE组CTDIvol、ED均值分别为（87．91±8．38）mGy／cm和�Objective： To evaluate the impact of ECG mA modulation method of 64-slice multi-detector CT （MDCT） on image quality and X-ray dosage in cr coronary artery imaging.Methods： 100 patients （54 male and 46 female, ages between 36 and 80, with average age of 55.4） underwent cardiac scans using GE LightSpecd 64-row VCT were divided into two groups with 50 patients each with the use OfECG mA modulation （UE group） and without （NE group）. The patient distributions in terms of sex, age, height, weight and heart rate were similar for the two groups with no significant difference （ P 〉 0.05）. The full mA portion covers 40% to 80% of the cardiac phases for the ECG mA modulation scans with mA modulation of 80%. The scanning were 120kV, 640mA, 0.35s rotation speed, 0.625mm slice thickness, 0.20-0.26 pitch, with body bewtie. For the two of UE and NE groups, the coronary scanning were performed with and without the use of ECG mA modulation, respectively, and recorded the CTDIw values for each group and converted into effective dose using European DLP method and conversion factor of 0.017 for chest CT scan to reflect overall dose to patients. Two experienced radiologists quantitatively evaluated the image quality blindly in terms of the number of coronary arteries and smaller branches identifled, the sharpness of vessel edges and the clarity of contrast agent in the vessel using scores of 1 - 4 with 4 being the highest. Image noises were also measured for the two sets with ROI of 100mm^2 placed at the center of the ascending aorta in the same place for both groups. The statistical analyses were performed with the spss 10.0 software. Results：The image quality scores for the NE and UE groups were 3.56 ± 0.54 and 3.68 ± 0.47, respectively. There was no significant difference between two groups with t-test （ P 〉 0.05）. The noise measurements for the NE and UE groups were 27.54 ± 4.52 and 28.09 ± 4.85, respectively, and no significant difference between the two groups （ P 〉0.05）. However, the

关 键 词：体层摄影术 X线计算机 冠状动脉 心电描记术 显像术 射线剂量 

分 类 号：R814.2[医药卫生—影像医学与核医学] R814.42[医药卫生—放射医学]