Accuracy of rectal endoscopic ultrasonography and magnetic resonance imaging in the diagnosis of rectal involvement for patients presenting with deeply infiltrating endometriosis.

OBJECTIVE To compare the accuracy of rectal endoscopic ultrasonography (REU) and magnetic resonance imaging (MRI) for predicting rectal wall involvement in patients presenting histologically proven deeply infiltrating endometriosis (DIE). METHODS This was a retrospective study of a continuous series of 81 patients presenting histologically proven DIE who underwent preoperative investigations using both REU and MRI. The sonographer and the radiologist, who were unaware of the clinical findings and patient history, but knew that DIE was suspected, were asked whether there was involvement of the digestive wall. RESULTS Rectal DIE was confirmed histologically in 34 of the 81 (42%) patients. For the diagnosis of rectal involvement, sensitivity, specificity and positive and negative predictive value for REU were 97.1%, 89.4%, 86.8% and 97.7% and for MRI they were 76.5%, 97.9%, 96.3% and 85.2%. CONCLUSION The sensitivity and negative predictive value of REU were higher than those of MRI suggesting that REU performs better than MRI in the diagnosis of rectal involvement for patients presenting with DIE. Prospective studies with a large number of patients are needed in order to validate these preliminary results.