16排CT对冠状动脉桥血管病变评估的临床应用价值

目的探讨16排计算机断层扫描技术对冠状动脉桥血管病变评估的临床应用价值。方法本研究共入选62例冠状动脉旁路移植术后患者,其中6例因心率控制不佳被排除。对其余56例共152条桥血管(其中内乳动脉桥48条,隐静脉桥104条)分别用16排CT造影(CTA)和常规冠状动脉造影(CAG)进行检查。CTA检查均通过回顾性心电图门控方法进行。患者平均心率(58±6)次/min。在CTA检查过程中以4ml/s速度静脉注入120ml的Visipaque320造影剂。冠状动脉桥血管的通畅和狭窄程度由两位有经验的医师来评估。结果在本研究中,CTA方法能显示所有冠状动脉桥血管;CTA还能显示所有桥血管近端吻合处以及71%的远端吻合处。并且,经CTA检查发现有29条桥血管发生闭塞,13条桥血管有显著狭窄病变。通过CAG检查比较CTA结果证实:在所有42条CTA检查发现闭塞或狭窄的冠状动脉桥血管中,CAG显示有34条桥血管有闭塞或狭窄;在所有110条CTA检查显示正常的冠状动脉桥血管中,CAG显示有108条桥血管正常,有8例假阳性和2例假阴性发生。CTA检查的敏感性94%,特异性95%;阳性预测值86%,阴性预测值99%。结论CTA可提供清晰的冠状动脉桥血管图像以及较高的诊断准确性。CTA可作为评估冠状动脉桥血管病变的一种无创检查方法。

The clinical value of sixteen-detector row computed tomography angiography for the assessment of coronary artery bypass graft

OBJECTIVE: The aim of this study was to evaluate the value of sixteen-detector row computed tomography angiography (CTA) for the assessment of coronary artery bypass graft (CABG). METHODS: Sixty-two consecutive patients undergoing coronary artery bypass grafting were recruited. Among them, 6 patients were excluded from the study due to unfavorable control of heart rate. A total of 56 patients with 152 coronary artery bypass grafts (internal mammary artery, n = 48; saphenous venous grafts, n = 104) were examined by computed tomography angiography (CTA) with sixteen-detector row CT and by conventional invasive coronary angiography (CAG). All CT procedures were performed with retrospective electrocardiogram gating method. The patients' mean heart rate was 58 +/- 6 beats/minute. 120 ml of Visipaque 320 were continuously injected with the rate of 4.0 ml/sec during the procedure. The patency and the stenosis of coronary artery bypass grafts were evaluated by two experienced readers. RESULTS: All the coronary artery bypass grafts were visualized by CTA, and all the proximal bypass anastomoses and 71% of the distal bypass anastomoses were also visualized by CTA. Furthermore, 29 occlusions and 13 significant stenoses of coronary artery bypass grafts were detected by CTA. The comparison of the results between CTA and CAG showed that among all the 42 occluded and stenosed coronary artery bypass grafts detected by CTA, 34 were confirmed by CAG; among all the 110 normal coronary artery bypass grafts detected by CTA, 108 were confirmed by CAG. There were 8 false positive and 2 false negative findings, resulting in a sensitivity of 94%, a specificity of 95%, a positive predictive value of 86%, and a negative predictive value of 99%. CONCLUSION: Sixteen-detector row CTA technology may provide a reliable visualization and higher diagnostic accuracy of coronary artery bypass grafts lesions. This technique can be used as a noninvasive procedure for the diagnosis of suspected coronary artery bypass grafts dysfunction.