Location-dependent value of pelvic MRI in the preoperative diagnosis of endometriosis

Abstract

Objectives: To investigate the value of magnetic resonance imaging (MRI) in the preoperative diagnosis of specific anatomical locations of endometriosis.

Study design: Between July 2008 and April 2011, 152 women (mean age 33.5 ± 6.1 years) with clinical and sonographic suspicion of endometriosis underwent pelvic MRI using T2 and unenhanced T1 sequences with and without fat saturation. Two radiologists interpreted the following regions by consensus according to a standardized protocol: ovaries, vagina, pouch of Douglas, rectosigmoid colon, uterosacral ligament (USL), bladder, peritoneum, and other pelvic regions. The results of MRI were retrospectively correlated with the laparoscopic and histopathologic findings. The main outcome parameters, sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), accuracy, positive likelihood ratio (LR+) and the negative likelihood ratio (LR-), were determined.

Results: Sensitivity, specificity, PPV, NPV, accuracy, positive and the negative likelihood ratio were 87.6%, 84.6%, 94.3%, 70.2%, 86.8%, 5.69 and 0.15 for the pouch of Douglas (vagina: 81.4%, 81.7%, 79.2%, 83.8%, 81.6%, 4.45, 0.23; rectosigmoid colon: 80.2%, 77.5%, 80.2%, 77.5%, 78.9%, 3.56, 0.25; USL: 77.5%, 68.2%, 77.5%, 68.2%, 73.7%, 2.44, 0.33; ovaries: 86.3%, 73.6%, 78.4%, 82.8%, 80.3%, 3.27, 0.19; urinary bladder: 81.0%, 94.7%, 70.8%, 96.9%, 92.8%, 15.15, 0.20; peritoneum: 35.3%, 88.1%, 60.0%, 73.0%, 70.4%, 2.97, 0.73). All endometriotic implants at other localization were detected (abdominal wall in 4, groin in one patient).

Conclusions: The value of MRI in preoperative diagnosis of endometriosis is dependent on the location of endometriosis. The highest accuracy was found in bladder endometriosis and the lowest in peritoneal endometriosis.