Deep pelvic endometriosis: limited additional diagnostic value of postcontrast in comparison with conventional MR images

Objectives: To determine the value of postcontrast MR imaging (MRI) in cases of suspected pelvic endometriosis by assessing interobserver variability of MR imaging according to the endometriotic locations.

Methods: This retrospective study included 158 patients with clinical suspicion of endometriosis who had undergone surgery after MRI between January 2004 and April 2009. Three radiologists with different degrees of experience were independently asked to determine the presence of rectosigmoid colon, vaginal, and bladder endometriosis using both conventional and a combination of conventional and postcontrast MRI. Descriptive analysis, ROC analysis and interobserver agreements (kappa values) were calculated.

Results: Rectosigmoid colon, vaginal, and bladder endometriosis was present in 65, 39 and eight patients, respectively. The accuracy of conventional assessment for readers 1, 2, and 3 for rectosigmoid colon, vaginal and bladder endometriosis was 77.2%, 74.1% and 96.8%, and 73.4%, 76.6% and 98.7%, and 86.1%, 88.6% and 99.4%, respectively. The accuracy of conventional and postcontrast MR images for readers 1, 2, and 3 for rectosigmoid colon, vaginal and bladder endometriosis was 77.8%, 78.5% and 98.1%, and 83.5%, 83.5% and 99.4%, and 87.3%, 89.2% and 99.4%, respectively.

Conclusions: Interobserver variability of MRI using conventional MRI alone is excellent for the diagnosis of DPE. No significant benefit of intravenous gadolinium, rectal or vaginal administration has been demonstrated.