Comparison between transvaginal sonography, saline contrast sonovaginography and magnetic resonance imaging in the diagnosis of posterior deep infiltrating endometriosis

OBJECTIVE: To compare clinical evaluation, transvaginal sonography (TVS), saline contrast sonovaginography (SCSV) and magnetic resonance imaging (MRI) in the diagnosis of posterior deep pelvic endometriosis (DPE). METHODS: Women suspected of having posterior DPE on the basis of subjective symptoms and clinical evaluation underwent digital vaginal and rectal examination, TVS, SCSV and MRI. Laparoscopy was performed and specimens were sent for histological examination. Sensitivity, specificity, positive and negative predictive value, as well as positive and negative likelihood ratios were analyzed for each diagnostic method. RESULTS: Fifty-four out of 102 women suspected of having posterior DPE underwent laparoscopic surgery. Among these, in 46 (85.2%) cases DPE was confirmed at laparoscopic and histological examination. SCSV correctly identified 43 (93.5%) cases, presenting higher accuracy than did the other procedures. SCSV and MRI were more accurate in diagnosing and discriminating between the different locations of endometriotic lesions, with respective sensitivities of 94.7 and 73.1% for vaginal fornix, 88.9 and 66.7% for the uterosacral ligaments and 80.6 and 83.3% for involvement of the rectovaginal septum. The specificity of SCSV and MRI, respectively, was 97.1 and 94.3% for vaginal fornix, 95.6 and 95.6% for uterosacral ligaments and 100 and 77.8% for involvement of the rectovaginal septum. In the diagnosis of rectal endometriosis, we found a sensitivity of 66.7% for both techniques and specificity of 93.8% for SCSV and 95.8% for MRI. CONCLUSION: TVS should be used as the first-line diagnostic technique and SCSV and/or MRI as second-line methods in the diagnosis of posterior DPE.