双能CT成像技术在骶髂关节炎中的应用探讨

Application of dual-energy CT imaging technique in sacroiliitis

目的探讨利用双能CT(DECT)虚拟去钙(VNCa)技术检测骶髂关节炎患者骨髓水肿(BME)的可行性和诊断准确性。方法经临床确诊的骶髂关节炎患者47例共89个关节纳入研究,利用DECT的VNCa图像来显示BME,VNCa图像由两名独立医师采用二进制系统独立评分,用基于兴趣区的定量分析在VNCa图像上放置感兴趣区,并测量CT值,根据受试者工作特性(ROC)曲线和ROC曲线下面积计算VNCa图像CT值。以MRI诊断结果为参考标准评价诊断效果。结果在参与分析的89个骶髂关节中,MRI诊断出55个骶髂关节存在BME(62%)。医师1和医师2定性分析对DECT诊断BME的敏感性、特异性、准确性、阳性预测值(PPV)和阴性预测值(NPV)分别为87%(48/55)和93%(51/55)、94%(32/34)和91%(31/34)、82%(32/39)和89%(31/35)、90%(80/89)和92%(82/89)、96%(48/50)和94%(51/54)。医师间对VNCa图像上BME的阅读的一致性近乎完美(K=0.81)。医师1的ROC曲线下面积为0.93,以-33.4 HU为阈值,总体敏感性为90%(49/55),特异性为83%(28/34),准确性为87%(77/89)。医师2的ROC曲线下面积为0.91,以-42.35 HU为阈值,得出总体敏感性为94%(52/55),特异性为80%(27/34),准确性为87%(77/89)。结论DECT结合VNCa图像重建可以对骶髂关节炎患者的BME进行定性分析和定量分析,其精度与MRI相当,具有较高的可行性和诊断准确性。

Objective To explore the feasibility and diagnostic accuracy of dual-energy CT(DECT)virtual noncalcium(VNCa)technique in the detection of bone marrow edema(BME).Methods A total of 89 joints from 47 patients clinically diagnosed with sacroiliitis were included in the study.The DECT-based VNCa was used to visualize the BME.The VNCa image was scored independently by two independent physicians using a binary system.The region of interest(ROC)was placed on the VNCa imaging by quantitative analysis based on ROI,and the CT value was measured.The CT value of the VNCa image was calculated according to the receiver operating characteristic(ROC)curve and area under the ROC curve(AUC).MRI diagnosis results were used as the reference standard to evaluate the diagnostic effects.Results MRI diagnosis results showed that 55 of the 89 sacroiliac joints(62%)analyzed had a BME.According to the qualitative analysis by physician 1,the sensitivity,specificity,accuracy,positive predictive value(PPV),and negative predictive value(NPV)of DECT in diagnosing the BME were 87%(48/55),94%(32/34),82%(32/39),90%(80/89),and 96%(48/50),respectively.According to the qualitative analysis by physician 2,the sensitivity,specificity,accuracy,positive predictive value(PPV),and negative predictive value(NPV)of DECT in diagnosing the BME were 93%(51/55),91%(31/34),89%(31/35),92%(82/89),and 94%(51/54),respectively.The interpretations of BME on the VNCa image by two physicians were almost consistent(K=0.81).As for the diagnostic results of physician 1,the AUC was 0.93,with-33.4 HU as the threshold value,the overall sensitivity,specificity,and accuracy were 90%(49/55),83%(28/34),and 87%(77/89),respectively.As for the diagnostic results of physician 2,the AUC was 0.91,with-42.35 HU as the threshold value,the overall sensitivity,specificity,and accuracy were 94%(52/55),80%(27/34),and 87%(77/89),respectively.Conclusion DECT in combination with VNCa image reconstruction,featured by high feasibility and diagnostic accuracy,can be used for qualitative and quantitative analysis of BME in patients with sacroiliitis,showing accuracy comparable to MRI.