双源CT大螺距前瞻性双次扫描模式在冠状动脉旁路移植术后随访中的应用

摘要

目的 探讨双源CT大螺距前瞻性心电门控双次扫描模式(Double Flash)在冠脉旁路移植(CABG)术后随访中的应用价值.方法 纳入2012年4月-2014年12月在解放军总医院采用冠状动脉CT成像(CCTA)检查的CABG术后患者61例,采用随机数字表法将患者分为A组(Double Flash扫描模式,30例)和B组(回顾性心电门控螺旋扫描模式,31例).由两位高年资医师以双盲法采用4分法(1分为优秀,4分为不能诊断)评价图像质量,分别记录计算两种扫描模式患者的容积CT剂量指数(CTDIvol)和有效辐射剂量(ED).结果 两组冠状动脉移植血管共有139根.其中A组移植血管69根,包括动脉桥25根,静脉桥44根;B组移植血管70根,包括动脉桥29根,静脉桥41根.A组的图像质量评分(1.22±0.57)与B组(1.21±0.61)比较差异无统计学意义(P＞0.05).A组的ED和CTDIvol(分别为4.34± 1.88mSv和5.70±2.36mGy)明显低于B组(分别为17.07±2.13mSv和40.95±3.12mGy),差异均有统计学意义(P＜0.001).结论 与普通回顾性心电门控螺旋扫描模式比较,双源CT Double Flash扫描模式可在保证图像质量的同时明显降低辐射剂量,可应用于CABG的术后随访.%Objective To evaluate the application of high-pitch dual-source CT with prospective ECG gated double scan mode (Double Flash) in postoperative follow-up of coronary artery bypass grafting (CABG).Methods Sixty-one patients undergone CABG and received coronary CT angiography (CCTA) from Apr.2012 to Dec.2014 were enrolled in present study.The patients were randomly divided into two groups according to scanning mode:group A (Double Flash mode,30 cases) and group B (retrospective ECG gated spiral mode,31cases).Evaluation parameters included volumetric CT dose index (CTDIvol) and effective radiation dose (ED).All the coronary segments were evaluated with double blind method by two independent observers according to the image quality (IQ) on 4-point scale (1:excellent to 4:non-diagnostic).Results There were 139 coronary artery bypass grafts in 2 groups.Group A had 69 grafts,including 25 artery grafts and 44 venous grafts.Group B had 70 grafts,including 29 grafts and 41 venous grafts.No significant difference was found in IQ.between the two groups for all coronary segments (1.22 ± 0.57 vs.1.21 ± 0.61,P=0.975).ED (4.34 ± 1.88 vs.17.07 ± 2.13mSv,P＜0.001) and CTDIvol (5.70 ± 2.36 vs.40.95 ± 3.12mGy,P＜0.001) were significantly lower in group A than in group B.Conclusion Double Flash spiral protocol of dual-source CCTA can acquire good image quality with reduced radiation dose during assessment of CABG patency,and might have potential value in the follow-up of CABG patency.