Diagnostic value of magnetic resonance imaging for malignant ovarian tumors mis-subclassified by the ultrasound-based ADNEX model

Meijiao Jiang ^1* Congcong Yuan ² Siwei Lu ^1* Yunkai Zhu ^3* Caiting Chu ^1* Wenhua Li ^1,4*

• ¹ Department of Radiology, Xinhua Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
• ² Department of Ultrasound Diagnosis, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, Shanghai Municipality, China
• ³ Department of Ultrasound Diagnosis, Xinhua Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, Shanghai Municipality, China
• ⁴ Department of Radiology, Chongming Branch, Xinhua Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, Shanghai Municipality, China

Objective: Accurately predicting metastatic cancer to the adnexa, stage I and advanced ovarian cancer before surgery is crucial. The ADNEX model, based on ultrasound, is currently the only prediction model that can differentiate between these types. This study aims to analyze MRI features and diagnostic value in malignant ovarian tumors mis-subclassified by the ADNEX model, considering their diverse histopathologic types.Methods: From January 2018 to September 2022, 164 patients with pathologically confirmed ovarian malignancies were selected from those who had examined by ultrasound. 51 patients mis-subclassified by ADNEX model were compared their clinical and MRI characteristics with histopathological types.Results: 30 were confirmed with primary ovarian cancer (5 with HGSOC, 14 with CCC, 2 with EC, 4 with MC, 2 with GCT, one with YST, one with immature teratoma, and one with dysgerminoma). 21 patients had metastatic ovarian tumors (10 with colorectal cancer, 4 with gastric cancer, 2 with uterine cervical cancer, 3 with endometrial cancer, one with breast cancer, and one with LAMN). The only significant difference between the two groups was in CEA. The mean diameter of the primary and metastatic ovarian tumors was 10.29cm (range: 3.61-26.02cm) and 8.58cm (range: 3.10-20.30cm), respectively. 42 masses were lobulated (82.35%, 42/51), 26 masses were solid-cystic (26/51, 50.98%). There was a significantly differences between CCC and other tumors, with mean ADC values of 1.01×10 -3 mm 2 /s (range: 0.68-1.28×10 -3 mm 2 /s) and 0.74×10 -3 mm 2 /s (range: 0.48-0.99×10 -3 mm 2 /s), respectively(P=0.000). 50 masses presented isointense-T1, hyperintense-T2 and hyperintense-DWI signal on MRI (50/51,98.04%). 33 masses showed intensive enhancement (33/51,64.71%). 17 masses had necrosis (17/51, 33.33%), with the majority being HGSOC, ovarian metastases from colorectal and gastric cancers (12/17, 70.59%). 19 masses presented hemorrhage (19/51,37.25%), with the majority being CCC (10/19, 52.63%). 46 masses were diagnosed correctly by MRI (46/51,90.20%). 35 and 15 masses were rated as O-RADS score 5 and score 4, respectively. One mass was rated as score 3. Conclusions: DWI signal, ADC value, degree of enhancement, and characteristic components within the mass on MRI can provide supplementary information for malignant ovarian tumors mis-subclassified by the ADNEX model.