MRI characteristics of FIGO stage IA epithelial ovarian cancer (EOC)

To investigate the MRI characteristics of FIGO stage IA EOC with different pathologic subtypes in order to improve the radiologists' understanding of these diseases.

In this retrospective study, we recruited patients who underwent surgery due to EOC at our hospital and were staged as FIGO IA from January 2013 to May 2024. The MR imaging and clinical features were evaluated by radiologists specialized in gynecology. Kruskal-Wallis test and Chi-squared test were performed to assess the difference between groups.

A total of 34 patients with a mean age of 56 years included serous carcinoma 9 cases (26 %), endometrioid carcinoma 9 cases (26 %), clear cell carcinoma 10 cases (29 %), mucinous carcinoma 6 cases (18 %). 2 patients synchronously developed ovarian cancer and uterus endometrial cancer. The median CA125 level was 65.6 U/ml (95 % CI, 21.6 to 92.8) and laterality ratio was 17:18 (left: right). Median diameter of tumor was 10.9 cm (95 % CI, 8.0 to 11.8). There were 6 cases of pure solid tumor, 5 cases of unilocular cystic-solid tumor and 23 multilocular cystic-solid tumor. 17 cases appeared hemorrhage signal and 6 of which had mixed signals in the loculi. As for enhancement pattern, total 10 cases of type I, 11 cases of type II and 13 cases of type III. Solid tissue in 33 (97 %) cases demonstrated restricted diffusion in DWI sequence. 9 cases presented ascites. There were 5 factors showed significant differences among different pathologic subtypes (p < 0.05), including maximum diameter, general morphology, growth pattern of solid tissue, grouped septa and presence of mixed signals in the loculi.

The imaging performance of FIGO stage IA EOC were variable, and there were differences in imaging characteristics among different pathological subtypes, which can improve current understanding of FIGO stage IA EOC and reduce clinical diagnostic omissions.