Diagnostic Accuracy Of Magnetic Resonance Imaging Versus Transvaginal Ultrasound For Posterior Deep Infiltrating Endometriosis:Compareing With Laparoscopic Surgery And Pathology

Objective:To analyze the image features and compare the diagnostic accuracy of T2 WI MRI and transvaginal ultrasound for the detection of posterior deep infiltrating endometriosis.Methods:Retrospective analysis of 78 consecutive women who underwent MRI and transvaginal ultrasound within 3 days between June 2017 and February 2019.Two MRI readers and a US reader were blinded to clinical and histopathologic findings.The laparoscopic surgery and pathology served as the golden standard.Diagnostic efficiency of MRI and TVS was analyzed and Chi square tests(McNemar)was used to compare the differences.The involvement of uterosacral ligament,rectovaginal septum and rectum whether or not were observed.The width,shape and signal of DIE lesions of uterosacral ligament were observed,measured and analyzed on MR.The involvement range,longitudinal diameter,depth,and signal of DIE lesions of rectum were measured and analyzed on MR.Results:1.The accuracy of MRI in the diagnosis of rectal endometriosis was 87.2%,60%and 100% respectively.2.MRI signal characteristics of rectal endometriosis: 30 cases with low signal onT2 WI and 8 cases with mixed signal on T2 WI.Among 15 cases involving serosa,11 cases were low signal on T2 WI,4 cases were mixed signal on T2 WI,23 cases involved muscular layer,19 cases were low signal on T2 WI and 4 cases were mixed signal on T2 WI.3.The average longitudinal diameter,median depth and median depth of rectal endometriosis lesions were 30.01 mm,28 mm(23,37),8.04 mm and 8(5,11)respectively.4.The average width of the left uterosacral ligament was 8.47 mm,median 8 mm(5,12)and that of the right uterosacral ligament was 6.45 mm,median 8 mm(4,8).As the diagnosis threshold of the right uterosacral ligament DIE lesion width was 7mm,the area under ROC curve was 0.98(95% CI: 0.971,0.990).As the diagnosis threshold of the left uterosacral ligament DIE lesion width was 5mm,the area under ROC curve was 0.988(95% CI: 0.980,0.995).5.The diagnostic accuracy,sensitivity,specificity,positive likelihood ratio and negative likelihood ratio of bilateral uterosacral ligaments on MRI were 84.5%,83.5%,83.7%,5.13 and 0.18,respectively.6.The sensitivity,specificity,false positive,false negative and diagnostic index of bilateral abnormal uterosacral ligament morphology on MRI were 99%,75%,1%,25%and 174%,respectively.7.The sensitivity,specificity,false positive,false negative and diagnostic index of low signal diagnosis of bilateral uterosacral ligaments on T2 WI were 92.5%,0,100%,7.5% and 92.5%,respectively.The accuracy and specificity of mixed signal diagnosis on T2 WI were 100%.8.The accuracy,sensitivity,specificity,positive likelihood ratio and negative likelihood ratio of MRI and TVS in the diagnosis of left uterosacral ligament were 87.2%vs 79.5%,84% vs 74%,92.9% vs 89.3%,11.76 vs 6.91,0.17 vs 0.29,respectively.There was no statistical difference between the two methods(P=0.344).9.The accuracy,sensitivity,specificity,positive likelihood ratio and negative likelihood ratio of MRI and TVS in the diagnosis of right uterosacral ligament were 82.3%vs 69.2%,85.7% vs 65.1%,66.7% vs 86.7%,2.571 vs 4.88 and 0.21 vs 0.4,respectively.There was statistical difference between the two methods(P=0.000).10.The accuracy,sensitivity,specificity,positive likelihood ratio and negative likelihood ratio of MRI and TVS in the diagnosis of rectovaginal septum were 88.5% vs82.1%,68% vs 52%,98.1% vs 96.2%,36.04 vs 13.78,0.33 vs 0.5,respectively.There wasno statistical difference between the two methods(P=0.453).11.The accuracy,sensitivity,specificity,positive likelihood ratio and negative likelihood ratio of MRI and TVS in rectal diagnosis were 87.2% vs 68%,88.9% vs 77.8%,85.7% vs 59.5%,6.23 vs 1.92,0.13 vs 0.37,respectively.There were no statistical differences between the two methods(P=0.167).Conclusion:1.MRI and TVS can accurately,non-invasively and effectively evaluate posterior pelvic endometriosis such as uterosacral ligament,rectovaginal septum and rectum before operation.Compared with TVS,MRI has higher diagnostic value for right uterosacral ligament.2.The accuracy of evaluating the involvement extent of EM lesions in rectum on MRI is high.The diagnostic accuracy of EM lesions involving muscular layer can reach100%.The underestimated cases are all those involving serosa layer.The main manifestations of rectal EM lesions were low signal intensity on T2 WI and mixed signal intensity on T2 WI in some cases.About half of the EM lesions involving serosa were low signal intensity on T2 WI,which is also the cause of underestimation of rectal EM lesions.3.The sensitivity and specificity of MRI in the diagnosis of abnormal morphology of uterosacral ligament adhesion are high,which is of high value in the diagnosis of endometriosis.EM of uterosacral ligament is mainly manifested as low signal on T2 WI,and a few manifested as mixed signal on T2 WI.The diagnostic accuracy and specificity of mixed signal on T2 WI are very high,while the overestimated cases and missed cases are all low signal on T2 WI,and the value of diagnosis of endometriosis only relying on low signal on T2 WI is not high.4.Conventional MRI can accurately assess EM lesions in the posterior pelvis,without cleaning the intestine and placement of fillers in the rectum and vagina.