Prediction of grading of ovarian endometrioid carcinoma using conventional MRI features

Objective: The purpose of this study was to evaluate MRI findings of ovarian endometrioid carcinoma (OEC) as a predictor of histological grade.

Materials and methods: This study included 60 patients with histopathologically confirmed OEC (20, 30, and 10 with grades 1, 2, and 3, respectively). Clinical and MRI results were retrospectively reviewed. We compared the following parameters between the three grades: age, tumor markers, presence of uterine corpus cancer, bilaterality, configuration, peritoneal dissemination, abnormal ascites, signal intensities of cystic and solid components, tumor size, and apparent diffusion coefficient (ADC) values of solid components.

Results: T1-hyperintense cysts were more common in grade 1 than in grades 2-3 OEC (80% vs. 60%, vs. 40%, p < 0.05). The signal intensity ratio between the cystic components with the largest solid component and muscle (1.49 vs. 1.08 vs. 0.98, p < 0.05) was higher in grade 1 than in grades 2-3 OEC. Necrosis within solid components was less common in grade 1 than in grades 2-3 OEC (31% vs. 68% vs. 88%, p < 0.05), and the ADC values of solid components were higher in grade 1 than in grades 2-3 OEC (1.10 vs. 0.99 vs. 0.79 × 10^-3 mm2/sec, p < 0.05). There were no significant differences in other factors.

Conclusion: On T1-weighted images, grade 1 OEC showed a higher signal intensity in the cystic components than grades 2-3 OEC. Necrosis and lower ADC values were more frequently observed in grades 2-3 than in grade 1 OEC.