Endometriomas: Diagnostic performance of US

PURPOSE: To determine the diagnostic performance of specific ultrasonograph ic (US) features in discriminating endometriomas from other adnexal masses. MATERIALS AND METHODS: Two sonologists independently reviewed the sonograms of 252 adnexal masses in 226 women and recorded US features by using a sta ndardized checklist. The diagnostic performance of specific US features and overall reviewer impression in discriminating endometriomas from other adn exal masses were evaluated. RESULTS: There were 40 endometriomas. Diffuse low-level internal echoes wer e present in 38 (95%) endometriomas and 40 (19%) nonendometriomas (positive likelihood ratio, 5). The positive likelihood ratio for the diagnosis of e ndometrioma increased to 8 if masses with neoplastic features at gray-scale US were excluded, allowing identification of 30 endometriomas (75%). The p resence of multilocularity or hyperechoic wall foci further increased the p ositive likelihood ratio to 48, allowing the identification of 18 endometri omas (45%). CONCLUSION: An adnexal mass with diffuse low-level internal echoes and abse nce of particular neoplastic features is highly likely to be an endometriom a if multilocularity or hyperechoic wall foci are present. A patient with a mass with diffuse low-level internal echoes and other US features may bene fit from additional imaging.