Accuracy of transvaginal sonography and rectal endoscopic sonography in the diagnosis of deep infiltrating endometriosis

Abstract

Objectives: To compare the accuracy of transvaginal sonography (TVS) and rectal endoscopic sonography (RES) for the diagnosis of deep infiltrating endometriosis (DIE), with respect to surgical and histological findings.

Methods: This was a longitudinal study of 81 consecutive patients referred for surgical management of DIE, who underwent both TVS and RES preoperatively. The diagnostic criteria were identical for TVS and RES, and were based on visualization of hypoechoic areas in specific locations (uterosacral ligaments, vagina, rectovaginal septum and intestine). We calculated the sensitivity, specificity, predictive values and accuracy of TVS and RES for the diagnosis of DIE.

Results: Endometriosis was confirmed histologically in 80/81 (98.7%) patients. Endometriomas and DIE were present in 43.2% and 97.5% of the women, respectively. For the diagnosis of DIE overall, TVS and RES, respectively, had a sensitivity of 87.3% and 74.7%, a positive predictive value of 98.6% and 98.3%, and an accuracy of 86.4% and 74%. For the diagnosis of uterosacral endometriosis, they had a sensitivity of 80.8% and 46.6%, a specificity of 75% and 50.0%, a positive predictive value of 96.7% and 89.5% and a negative predictive value of 30% and 9.3%. For the diagnosis of intestinal endometriosis, they had a sensitivity of 92.6% and 88.9%, a specificity of 100% and 92.6%, a positive predictive value of 100% and 96% and a negative predictive value of 87% and 80.6%.

Conclusion: TVS is apparently more accurate than is RES for predicting DIE in specific locations, and should thus be the first-line imaging technique in this setting.