Characterization of adnexal lesions using photoacoustic imaging to improve sonographic O‐RADS risk assessment.

Objective: To assess the impact of photoacoustic imaging (PAI) on the assessment of ovarian/adnexal lesion(s) of different risk categories using the sonographic ovarian‐adnexal imaging‐reporting‐data system (O‐RADS) in women undergoing planned oophorectomy. Method: This prospective study enrolled women with ovarian/adnexal lesion(s) suggestive of malignancy referred for oophorectomy. Participants underwent clinical ultrasound (US) examination followed by coregistered US and PAI prior to oophorectomy. Each ovarian/adnexal lesion was graded by two radiologists using the US O‐RADS scale. PAI was used to compute relative total hemoglobin concentration (rHbT) and blood oxygenation saturation (%sO2) colormaps in the region of interest. Lesions were categorized by histopathology into malignant ovarian/adnexal lesion, malignant Fallopian tube only and several benign categories, in order to assess the impact of incorporating PAI in the assessment of risk of malignancy with O‐RADS. Malignant and benign histologic groups were compared with respect to rHbT and %sO2 and logistic regression models were developed based on tumor marker CA125 alone, US‐based O‐RADS alone, PAI‐based rHbT with %sO2, and the combination of CA125, O‐RADS, rHbT and %sO2. Areas under the receiver‐operating‐characteristics curve (AUC) were used to compare the diagnostic performance of the models. Results: There were 93 lesions identified on imaging among 68 women (mean age, 52 (range, 21–79) years). Surgical pathology revealed 14 patients with malignant ovarian/adnexal lesion, two with malignant Fallopian tube only and 52 with benign findings. rHbT was significantly higher in malignant compared with benign lesions. %sO2 was lower in malignant lesions, but the difference was not statistically significant for all benign categories. Feature analysis revealed that rHbT, CA125, O‐RADS and %sO2 were the most important predictors of malignancy. Logistic regression models revealed an AUC of 0.789 (95% CI, 0.626–0.953) for CA125 alone, AUC of 0.857 (95% CI, 0.733–0.981) for O‐RADS only, AUC of 0.883 (95% CI, 0.760–1) for CA125 and O‐RADS and an AUC of 0.900 (95% CI, 0.815–0.985) for rHbT and %sO2 in the prediction of malignancy. A model utilizing all four predictors (CA125, O‐RADS, rHbT and %sO2) achieved superior performance, with an AUC of 0.970 (95% CI, 0.932–1), sensitivity of 100% and specificity of 82%. Conclusions: Incorporating the additional information provided by PAI‐derived rHbT and %sO2 improves significantly the performance of US‐based O‐RADS in the diagnosis of adnexal lesions. © 2023 International Society of Ultrasound in Obstetrics and Gynecology. [ABSTRACT FROM AUTHOR]