64排螺旋CT心肌灌注显像评价冠状动脉狭窄对心肌缺血的诊断效能

Diagnostic efficiency of 64-slice CT angiography of myocardial perfusion to myocardial ischemia of coronary stenosis

目的利用99mTc-MIBI心肌灌注显像(MPI)探讨64排螺旋CT冠状动脉造影(CTCA)发现的冠状动脉狭窄对心肌缺血的诊断效能。方法30例患者接受MPI和CTCA检查。将CTCA三支冠状动脉分为12段,以MPI为诊断标准,分别以CTCA血管狭窄≥50%和≥75%为截断值,统计对应节段MPI是否出现异常,分析CTCA诊断的冠状动脉狭窄对心肌缺血的效能评价。结果MPI发现灌注异常9例(6例可逆性,3例固定性血流灌注减低)。CTCA共分析327个冠状动脉节段,其中狭窄≥50%者占25段(7.65%);狭窄≥75%者12段(3.67%)。以MPI异常为标准观察病变血管,以狭窄≥50%为界值时,CTCA的敏感性、特异性、阴性预测值(NPV)、阳性预测值(PPV)和准确性分别是68.42%、96.14%、99.01%、52.00%和95.41%;以狭窄≥75%为界值,则分别为66.67%、99.04%、98.73%、66.67%、97.55%。以MPI异常为标准观察患者,当血管狭窄≥50%为界值时,CTCA的敏感性、特异性、NPV、PPV和准确性分别是66.67%、57.14%、80.00%、40.00%和60.00%;当≥75%为界值时,上述指标分别是55.56%、85.71%、81.82%、62.50%和76.67%。结论正常CTCA对心肌缺血患者的排查是可靠的,CTCA异常是否存在心肌缺血需要进一步检查。

Objective To investigate the diagnostic efficiency of 64-slice CT coronary angiography （CTCA） to myocardial ischemia of coronary stenosis. Methods ^99m Tc-MIBI myocardial perfusion imaging （MPI） and 64-slice CTCA were performed in 30 patients with myocardial ischemia of coronary stenosis. Three coronary arteries were divided in to 12 segments in each patient, the diagnostic efficiency of CTCA to myocardial ischemia of coronary stenosis were eveluated taking MPI as diagnostic standard, and stenoses ≥50% and ≥75% as the cutoff value. Results In 9 patients, perfusion defected were found （6 reversible, 3 fixed） on MPI. A total of 327 coronary arteries＇ segments were analyzed, quantitative CTCA revealed stenoses ≥50% in 25 segments （7.65%） and stenoses ≥75% in 12 segments （3.67%）. When the cut-off was ≥50%, the sensitivity, specificity, negative and positive predictive value （NPV, PPV） and accuracy of CTCA by the abnormal images of MPI as diagnostic standard to observe abnormal arteries was 68.42%, 96.14%, 99.01%, 52.00% and 95.41%, respectively; and 66.67%, 99.04%, 98.73%, 66.67% and 97.55%, respectively, when cut-off at ≥75%. Taking abnormal MPI as diagnostic standard to observe the patients, the sensitivity, specificity, NPV, PPV and accuracy of CTCA was 66.67%, 57.14%, 80.00%, 40.00% and 60.00% respectively, with the cut-off at ≥50%; and was 55.56%, 85.71%, 81.82%, 62.50% and 76.67%, respectively, with the cut-off at ≥75%. Conclusion Sixty-four-slice CTCA is a reliable tool to rule out functionally relevant myocardial ischemia of coronary artery disease. However, further examination is neeessory for patients with abnormal CTCA.