Clinical Utility of Doppler Ultrasonography in Preoperative Risk Stratification of Ovarian Masses: A Retrospective Multi-Centric Analysis.

Background: Differentiating benign from malignant ovarian lesions before surgery remains a significant clinical challenge. Reliable preoperative assessment is crucial for appropriate treatment planning and improving patient prognosis. Color Doppler ultrasonography, particularly through evaluation of the resistance index (RI), has gained attention as a non-invasive method for assessing tumor vascularity associated with malignancy. Objective: To assess the diagnostic performance of the resistance index measured by preoperative Doppler ultrasonography in distinguishing benign from malignant ovarian masses. Methods: We performed a retrospective study including 470 patients who underwent surgical exploration for adnexal masses at Al-Azhar University, Ain Shams University, Badya University and Zagazig University Hospitals between May 2020 and May 2025. Clinical parameters, sonographic findings, and final histopathological diagnoses were reviewed. Statistical analysis included logistic regression and receiver operating characteristic (ROC) curve analysis to determine the predictive accuracy of RI. Results: Malignant tumors exhibited significantly lower RI values compared to benign masses (mean 0.48±0.07). An optimal cutoff value of ≤0.54 yielded excellent discriminative ability, with an area under the ROC curve (AUC) of 0.966. At this threshold, sensitivity reached 85.2% and specificity 91.6%, with an overall accuracy of 90.2%. Additional sonographic features, including the presence of papillary projections and septations, were strongly linked to malignancy, whereas simple cystic appearance with thin walls was associated with benign pathology. Conclusions: The resistance index derived from Doppler ultrasonography represents a valuable and reliable parameter for preoperative characterization of ovarian masses. Its integration into routine imaging protocols may enhance early detection of malignancy and support more informed surgical decision-making.