Imaging characterization of adnexal lesions: Do CT findings correlate with US?

Objective: To compare contrast-enhanced CT and US agreement in characterizing adnexal lesions in late post-menopausal women.

Materials And Methods: This was a HIPAA-compliant IRB-approved retrospective review of the contrast-enhanced CTs of 130 late post-menopausal women (> 55 years). The lesions were classified as simple cystic, minimally complex cystic, complex cystic, solid-cystic, or solid based on CT and US morphology. Findings were analyzed to evaluate agreement between CT and US on adnexal lesion characterization.

Results: One forty-one adnexal lesions were assessed by both contrast-enhanced CT and US. Overall, there was good agreement between CT and US, which agreed on the lesion morphology in 114 (81%) cases with an unweighted kappa value of 0.68 (95% CI 0.56-0.78). By CT, 83 (59%) were classified as simple cystic, of which 73/83 (88%) were confirmed as simple cystic by US. Of the remaining 10 CT simple cysts, 9 were reclassified by US as minimally complex cystic and one as complex cystic. Eight of these lesions were benign based on pathology or follow-up imaging, while two lesions remained indeterminate. By CT, 27 lesions (19%) were classified as minimally complex, while US reclassified 13 (48%) of the lesions (eight to simple cystic and five as complex or solid-cystic). Among the 31 remaining lesions, there were 4 (13%) discordances between CT and US.

Conclusion: There is good agreement between CT and US in characterizing adnexal lesion morphology, particularly simple cysts. However, there was significant discordance seen with characterization of minimally complex cysts, indicating that these lesions need US follow-up.