三维动态增强MR血管造影诊断肾动脉狭窄:与DSA对照研究

目的评价三维动态增强磁共振血管造影(CEMRA)诊断肾动脉狭窄的价值.方法对28例可疑肾动脉狭窄的病人行CEMRA和DSA检查,由两位医师独立对图像进行分析均并最终达成一致,分5级记录肾动脉的情况,统计CEMRA诊断肾动脉狭窄(＞50%)的敏感度、特异性、阳性预测值和阴性预测值,并用ROC法分析其诊断价值.用CohenKappa法评价CEMRA与DSA在诊断肾动脉狭窄和对狭窄分级方面的一致性.观察副肾动脉显示情况.结果CEMRA诊断肾动脉狭窄(＞50%)的敏感度为95.0%、特异性为94.4%、阳性预测值为90.4%、阴性预测值为97.1%,其ROC曲线下面积为0.955,两种方法诊断肾动脉狭窄和对狭窄分级的κ值分别为0.924和0.899.CEMRA副肾动脉显示率为87.5%(7/8).结论CEMRA可以准确诊断有意义的肾动脉狭窄(＞50%),做出肾动脉狭窄的除外诊断,避免不必要的DSA检查,可作为诊断肾动脉病变的首选影像检查方法.

Three-dimensional contrast enhanced MR angiography in diagnosis of renal artery stenosis: comparison with DSA

Objective To assess the value of three-dimensional dynamic contrast-enhanced MR angiography (CEMRA) in the diagnosis of renal artery stenosis. Methods Twenty-eight consecutive patients suspected of renal artery stenosis underwent both DSA and CEMRA. Two radiologists evaluated the main renal arteries on CEMRA and DSA images in consensus. The renal arteries were recorded as five grades: Grade 1: normal; Grade 2: stenosis<50%; Grade 3: stenosis 50%-75%; Grade 4: stenosis>75%; Grade 5: occlusion. The data were analyzed by SPSS 11.5 software. The sensitivity, specificity, positive predictive value and negative predictive values of CEMRA were calculated. Receiver operating characteristic (ROC) analysis was performed for depiction of hemodynamically significant stenosis (>50%). Cohen Kappa analysis was used to assess agreement between the two imaging modalities in grading of stenosis and depiction of significant stenosis. Accessory renal arteries were also evaluated. Results The sensitivity, specificity, positive predictive value and negative predictive value of CEMRA for depiction of renal artery stenosis was 95.0%, 94.4%, 90.4%, and 97.1%, respectively. The area under the ROC curve was 0.955. Kappa was 0.924 for detection of significant stenosis and 0.899 for grading of stenosis. The detection rate of accessory renal artery was 87.5% (7/8). Conclusion CEMRA should be the first choice method in the diagnosis of renal artery stenosis. It can accurately diagnose significant stenosis (>50%), and have consistency with DSA in grading renal stenosis. Performing CEMRA in patients suspected of renal artery stenosis can help to avoid unnecessary DSA procedure.