Assessment of pelvic endometriosis: correlation of US and MRI with laparoscopic findings

The purpose of this study was to evaluate the contribution of ultrasound (US) and magnetic resonance (MR) imaging in the diagnosis and local staging of endometriosis by comparing results with laparoscopic findings. We evaluated 36 consecutive women with suspected or clinically diagnosed endometriosis. Thirty-two out of 36 patients met the following inclusion criteria: transabdominal and endocavitary (US) examination and MR imaging, followed by laparoscopy performed within 2 weeks. US and MR findings were classified based on location, number and morphology (small nodules, large nodules, laminar lesions, cystic lesions, complex lesions, adhesions, cul-de-sac obliteration). Laparoscopy, considered the gold standard, identified 143 lesions in 32 patients. US detected 101 lesions, and MR detected 92 lesions, which were subsequently divided by morphologic appearance. Sensitivity and specificity of the two imaging techniques in the recognition of the different locations were 58% and 25%, respectively, for US and 56% and 50%, respectively, for MR imaging. Results of the two techniques in the different locations examined were similar, with the exception of lesions in the rectovaginal septum, which were better detected by US, and for adhesions and cul-de-sac obliteration, which were more easily detected by MR. Both US and MR are accurate in the diagnosis of endometriosis. There are no significant differences in staging of pelvic endometriosis between US and MR. US examination is the primary evaluation in cases of suspected disease and for the rectovaginal septum. MR examination is recommended for correct classification in doubtful cases and in cases of suspected extrapelvic lesions and adhesions.