低心率下第二代双源CT冠脉成像Flash扫描与序列扫描图像质量及伪影比较

摘要

目的:比较低心率下CT前瞻性心电触发Flash扫描与序列扫描的冠状动脉图像质量及伪影.方法:回顾性连续收集Flash扫描(A组)与序列扫描(B组)冠状动脉CT成像各80例患者,心率均≤70次/min.4级法评价2组图像质量,初步分析伪影特点及成因.结果:A、B2组可评价冠状动脉节段为98.37％和99.29％,差异无统计学意义(x2＝3.56,P＝0.094);可评价患者为85.00％和96.25％,差异有统计学意义(x2=4.708,P＝0.035);平均节段质量评分为(1.295±0.60)分和(1.21±0.59)分,差异有统计学意义(Z=-2.591,P＝0.010).A组的4级图像大部分分布于右冠中远段,多数出现在心率大于65次/min的患者中,均为心脏搏动伪影.B组4级图像散在分布于冠脉各段中,为呼吸及心脏搏动伪影.A组辐射剂量明显低于B组,差异有统计学意义.结论:低心率下Flash与序列扫描均可获得高质量冠状动脉图像,序列扫描略优于Flash扫描;Flash扫描右冠状动脉中远段出现心脏搏动伪影概率大,序列扫描易产生呼吸及心律不齐所致伪影.%Objective:To compare the image quality and analyze the artifacts between the prospective ECG-gated high-pitch spi ral mode (Flash mode) and the prospective ECG-gated sequential acquisition mode(sequential mode)for coronary artery imaging in lower heart rate.Methods:Each group had 80 subjects with heart rate ≤70 bpm.In group A,CT was performed using Flash mode,and the data acquisition was obtained at 60％ of the R-R interval.In group B,Data was collected using the sequential mode at 35 ％-75 ％ of the R-R interval.Image quality (IQ) was evaluated using a four-point scale (1 =excellent,4 =unevaluable).Results:There was no significant difference between two groups on the basis of segment in image quality(group A,98.37％ ; group B,99.29％ ; P=0.094),but there was significant difference on the basis of patient(group A,85％ ; group B,96.25％; P=0.035)andinmeanIQscore between groups (1.295±0.60 vs.1.21±0.59,Z=-2.591,P=0.010).In group A,all of IQ score in 4th were shown at the middle and distal segments of the right coronary artery,and these artifacts were not caused by respiratory motion,and the heart rates of most of these cases were more than 65 bpm.In group B,however,the artifacts with IQ score in 4th were randomly distributed in three branches of coronary artery.They were caused by both of breathing and cardiac motion.Conclusion:At the low heart rate,the high quality of coronary artery imaging can be similarly acquired by Flash and sequential scan mode,respectively.However,in Flash mode,the cardiac motion artifacts happened more easily at the middle and distal segments of the right coronary artery.