Objective: To compare the accuracy of magnetic resonance enema (MR-e) and rectal water-contrast transvaginal sonography (RWC-TVS) in the diagnosis of rectosigmoid endometriosis.
Methods: This prospective study included 286 patients of reproductive age with clinical suspicion of rectosigmoid endometriosis. Patients underwent MR-e and RWC-TVS before laparoscopic excision of endometriotic lesions. The findings of MR-e and RWC-TVS were compared with surgical and histological results.
Results: Of the 286 patients included in the study, 151 (52.8%) had rectosigmoid endometriosis. MR-e and RWC-TVS had similar accuracy in the diagnosis of rectosigmoid endometriosis (P = 0.063). In the diagnosis of rectosigmoid endometriosis with MR-e, the sensitivity was 95.4% (95% CI, 90.7-99.1%), specificity was 97.8% (95% CI, 93.6-99.5%), positive predictive value (PPV) was 98.0% (95% CI, 94.1-99.6%), negative predictive value (NPV) was 95.0% (95% CI, 89.9-97.9%), positive likelihood ratio (LR+) was 42.91 (95% CI, 14.01-131.46) and negative likelihood ratio (LR-) was 0.05 (95% CI, 0.02-0.10). For diagnosis with RWC-TVS, sensitivity was 92.7% (95% CI, 87.3-96.3%), specificity was 97.0% (95% CI, 92.6-99.2%), PPV was 97.2% (95% CI, 93.0-99.2%), NPV was 92.3% (95% CI, 86.6-96.1%), LR+ was 31.29 (95% CI, 11.90-82.25) and LR- was 0.08 (95% CI, 0.04-0.13). MR-e and RWC-TVS underestimated the size of the endometriotic nodules; for both imaging techniques the underestimation was greater for nodules with a diameter ≥ 30 mm. There was no significant difference in the mean intensity of pain experienced by the patients during the two examinations.
Conclusions: RWC-TVS should be the first-line investigation in patients with clinical suspicion of rectosigmoid endometriosis and physicians should be trained in performing this examination. Considering that MR-e is more expensive than RWC-TVS, it should be used only when the findings of RWC-TVS are unclear. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.
Keywords: bowel endometriosis; diagnosis; endometriosis; magnetic resonance; transvaginal ultrasonography.
Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.