双能CT虚拟去钙技术对股骨头坏死的诊断价值

目的:探讨双能CT虚拟去钙技术(VNCa)对股骨头坏死的诊断价值。方法:回顾性分析86例临床拟诊为股骨头坏死患者的常规CT、VNCa和MR图像。共172个髋关节,其中股骨头坏死120个,正常股骨头52个。以MRI诊断结果作为参考标准,阅片者1、2分别进行两次诊断分析:A组仅使用常规CT图像,B组使用常规CT和VNCa图像,比较两组的诊断结果。测量并比较股骨头坏死区与正常股骨头在VNCa和常规CT(rCT)图像上的CT值(CTVNCa和rCT),并进行ROC曲线分析。结果:A组中阅片者1对股骨头坏死的诊断敏感度、特异度、符合率、阳性和阴性预测值分别为0.750、0.962、0.814、0.978和0.577;阅片者2分别为0.791、0.952、0.843、0.979和0.667。B组中阅片者1的诊断敏感度、特异度、符合率、阳性和阴性预测值分别为0.933、0.904、0.919、0.957和0.855;阅片者2分别为0.958、0.923、0.948、0.966和0.868。B组的诊断敏感度、符合率和阴性预测值较A组明显提高,曲线下面积分别由0.559、0.545提高到0.899、0.879。两位阅片者测量的股骨头坏死区的CTVNCa值均显著高于正常股骨头,差异具有统计学意义(Z=-8.294,P<0.0001;Z=-7.876,P<0.0001)。两位阅片者测量的股骨头坏死区和正常股骨头的常规CT值的差异无统计学意义(Z=-1.227,P=0.220;Z=-0.994,P=0.345)。结论:基于双能CT的VNCa技术可用于股骨头坏死的诊断,且诊断效能较高。

Diagnostic performance of virtual non-calcium technique on dual-energy CT in osteonecrosis of the femoral head

Objective:To investigate the diagnostic performance of virtual non-calcium technique(VNCa)on dual-energy CT(DECT)in the detection of osteonecrosis of the femoral head.Methods:Conventional and VNCa DECT images and MR images of 89 patients with clinically suspected osteonecrosis of femoral head were retrospectively collected and analyzed.A total of 172 hips(including 120 femoral heads with osteonecrosis and 52 normal femoral heads)were finally included according to selection criteria.Diagnosis was made by two radiologists in two sessions on two sets of CT images:group A,only conventional,and group B,both conventional and VNCa.MRI diagnosis results were taken as reference,diagnostic performances of the two reading sessions were compared.The CT values on VNCa and regular CT images in ROI named as CTVNCa and rCT were measured.Quantitative analyses of CTVNCa were performed and a cut-off value was obtained through receiver operating characteristic(ROC)analysis.Both VNCa and conventional CT values of the femoral head osteonecrosis and normal femoral head were compared according to MRI results.Results:In group A,the sensitivity,specificity,accuracy,positive predictive value(PPV)and negative predictive value(NPV)of reader 1 were 0.750,0.962,0.814,0.978 and 0.577,and those of reader 2 were 0.791,0.952,0.843,0.979 and 0.667,respectively.In group B,the sensitivity,specificity,accuracy,PPV and NPV of reader 1 were 0.933,0.904,0.919,0.957 and 0.855,and those of reader 2 were 0.958,0.923,0.948,0.966 and 0.868,respectively.The sensitivity,accuracy and NPV value were improved in the second session for both readers.Compared with group A,the area under the ROC curve increased from 0.559,0.545 to 0.899 and 0.879,respectively.CT values on VNCa images of early osteonecrosis of the femoral head were significantly higher than those of normal femoral head with significant differences(Z=-8.294,P<0.0001;Z=-7.876,P<0.0001).There was no significant difference between regular CT values of osteonecrosis of the femoral head and the normal femoral head(Z=-1.227,P=0.220;Z=-0.994,P=0.345).Conclusion:Virtual non-calcium technique on dual-energy CT can be useful in detection of osteonecrosis of the femoral head with higher diagnostic performance compared with conventional CT.