Fat-containing adnexal masses on MRI: solid tissue volume and fat distribution as a guide for O-RADS Score assignment

摘要

Purpose To explore ways to improve O-RADS MRI scoring for fat-containing adnexal masses, by investigating methods for quantifying solid tissue volume and fat distribution and evaluating their associations with malignancy. Methods This retrospective, single-center study included patients with fat-containing adnexal masses on MRI during 2008-2021. Two radiologists independently reviewed overall size (Size(overall)), size of any solid tissue (Size(anysolid)), size of solid tissue that was not Rokitansky nodule (Size(non-Rokitansky)), and fat distribution. Wilcoxon test, Fisher-exact test, and ROC curve analysis were performed. Reference standard was pathology or follow-up > 24 months. Results 188 women (median age 35 years) with 163 benign and 25 malignant lesions were included. Size(overall) (R1, 9.9 cm vs 5.9 cm; R2, 12.4 cm vs 6.0 cm), Size(anysolid) (R1, 5.1 cm vs 1.2 cm; R2, 3.2 cm vs 0.0 cm), Size(non-Rokitansky) (R1, 5.1 cm vs 0.0 cm; R2, 3.1 cm vs 0.0 cm), and fat distribution differed significantly between malignant and benign lesions (p = 1.2 cm; R2, >= 1.0 cm) yielded sensitivity and specificity of 0.72 and 0.93 (R1) and 0.76 and 0.95 (R2). Among immature teratomas, 85.7 displayed scattered fat. Conclusion Overall size, size of (any or non-Rokitansky-nodule) solid tissue, and fat distribution differed between benign and malignant fat-containing adnexal masses. Incorporating these would constitute simple and practical approaches to refining O-RADS MRI scoring.