Accuracy of magnetic resonance imaging and rectal endoscopic sonography for the prediction of location of deep pelvic endometriosis

BACKGROUND: We compared the accuracy of magnetic resonance imaging (MRI) and rectal endoscopic sonography (RES) for the diagnosis of deep pelvic endometriosis (DPE), with respect to surgical and histological findings. METHODS: Longitudinal study of 88 consecutive patients referred for surgical management of DPE, who underwent both MRI and RES pre operatively. The diagnostic criteria were identical for MRI and RES and were based on visualization of hypointense/hypoechoic areas in specific locations. DPE was diagnosed when at least one site was involved. We calculated the sensitivity, specificity, predictive values, accuracy and 95% confidence interval of MRI and RES for DPE. RESULTS: DPE and endometriomas were present in 97.7 and 39.7% of women, respectively. The sensitivity, specificity and positive and negative predictive values of MRI and RES, respectively, were 84.8 and 45.6%, 88.8 and 40%, 98.5 and 87.8% and 40 and 8.5% for uterosacral endometriosis; 77.7 and 7.4%, 70% and 100, 85.3 and 100% and 89.7 and 70.9% for vaginal endometriosis and 88.3 and 90%, 92.8 and 89.3%, 96.4 and 94.7% and 78.8 and 80.6% for colorectal endometriosis. CONCLUSIONS: MRI is more accurate than RES for the diagnosis of uterosacral and vaginal endometriosis, whereas the two methods are similarly accurate for colorectal endometriosis.