双能CT虚拟去钙技术在踝关节处骨髓水肿中的诊断价值

Diagnostic Value of Dual-Energy CT Virtual Noncalcium Technique in Bone Marrow Edema of Ankle Joint

目的探讨双能CT(DECT)虚拟去钙(VNCa)技术在急性创伤患者踝关节处骨髓水肿(BME)中的诊断价值。方法63例患者在踝关节急性外伤后24h内接受双源DECT(80k VP和Sn140k VP)和MRI成像。DECT使用Liver VNC软件三材料分解法生成踝关节处的VNCa图像,由两名放射科医师使用二元系统对图像进行分级(1=存在BME,0=不存在BME),对VNCa图像的CT值进行受试者操作特性曲线(ROC)分析,以MRI结果作为“金标准”。结果MRI显示51/63例患者存在BME,DECT显示49/51例患者存在BME(96.08%),两名医师通过DECT的VNCa图像显示BME的敏感性、特异性、阴性预测值、阳性预测值和准确性分别为96.08%、91.67%、84.62%、98.00%、95.24%和96.00%、92.31%、85.71%、97.96%、95.24%,阅片医师间对DECT图像定性分级的一致性较高(Kappa=0.84)。定量分析DECT的阳性区域平均CT值为(-11.84±35.09)HU,阴性区域平均CT值为(-61.82±39.52)HU,两区域CT值对比有显著差异(P<0.001)。VNCa图像CT值曲线下面积(AUC)为0.83(95%置信区间0.73~0.93),诊断阈值为-24.14HU,定量分析DECT的敏感性、特异性、阴性预测值、阳性预测值和准确性分别为98.00%、92.31%、92.31%、98.00%、96.83%。结论DECT可以诊断踝关节处急性创伤背景下的BME,与MRI相比无明显差别。

Objective To explore the diagnostic value of dual-energy CT virtual noncalcium technology in bone marrow edema at the ankle of patients with acute trauma.Methods Sixty-three patients underwent DECT scan and MRI imaging within 24 hours after acute ankle trauma.VNCa images at the ankles were generated with Liver VNC software by three-factor analysis using DECT scan.These images were graded by two radiologists using a binary system(1=presence of BME,0=absence of BME);CT values of the VNCa images were analyzed by receiver operating characteristic curve(ROC),and MRI results were used as"golden standard".Results The results of MRI imaging showed that BME was present in 51/63 patients(80.95%),and the results of DECT scan showed that BME was present in 49/51patients(96.08%).The DECT-VNCa images analyzed by the two radiologists showed that the sensitivity,specificity,negative predictive value,positive predictive value and accuracy of BME were 96.08%,91.67%,84.62%,98.00%,95.24%and 96.00%,92.31%,85.71%,97.96%,95.24%,respectively.The consistency of qualitative grading of DECT images by them was higher(Kappa=0.84).Quantitative analysis of these images showed that the average CT value of the positive area was(-11.84±35.09)HU,and the average CT value of the negative area was(-61.82±39.52)HU;There was a significant difference between the CT values of the two areas(P<0.001),and the difference was statistically significant.The area under the curve(AUC)for the CT values of the VNCa images was 0.83(95%confidence interval is from 0.73 to 0.93),and the diagnostic threshold was-24.14HU.The sensitivity,specificity,negative predictive value,positive predictive value,and accuracy of the quantitative analysis of DECT were 98.00%,92.31%,92.31%,98.00%,96.83%.Conclusion DECT can be used to diagnose BME in the context of acute trauma at the ankle,and it has no significant difference compared with MRI.