Ovarian Masses and O-RADS

A Systematic Approach to Evaluating and Characterizing Adnexal Masses With Ultrasound

Ana Mitchell, MD; Austin Kwong, MD; Simran Sekhon, MD; John P McGahan, MD, FACR


Appl Radiol. 2021;50(3):24-31. 

In This Article

O-RADS 4 and 5 Lesions

Worrisome ultrasound features of O-RADS 4 and 5 lesions include the presence of multilocular cysts, solid components within the lesion, papillary projections, large size, and higher color flow grades (Table II, Figures 6, 7). These features can be present in solid lesions such as sex cord tumors or ovarian metastases, which will be explained in greater detail in Part II of this review (Table 4). Of these lesions, the most worrisome are surface epithelial neoplasms. These tumors constitute approximately 90% of all malignant ovarian tumors and include serous or mucinous cyst adenocarcinomas. Serous neoplasms have a higher frequency of malignancy than do mucinous neoplasms.

Figure 6.

Fallopian tube cancer. (A) Longitudinal view demonstrates a multiseptated mass with mural nodularity and color flow (arrow). (B) Coronal image through the same region demonstrates mural nodularity with strong color flow noted within this mass (arrow) and with thick septations. These findings are strongly indicative of malignancy (O-RADS 4 or 5).

Figure 7.

Ovarian mucinous adenocarcinoma. (A) Ultrasound examination demonstrates a >10 cm multilocular cyst with solid components with color flow (not shown). (B) Corresponding T2 MRI shows similar findings of a multilocular cyst with a solid component that enhanced avidly (not shown) (O-RADS MRI 5).

An unusual type of surface epithelial tumor with concerning features is the borderline tumor. These tumors are typically diagnosed pathologically after surgery. They occur in younger patients and have a 10-year survival rate as high as 95% (Figure 8). Surface epithelial neoplasms will be discussed in more detail in Part II.

Figure 8.

Borderline mucinous cystadenoma. (A) CT scan demonstrating large, predominantly cystic mass arising from the pelvis, with suggestions of septations within the mass. Free fluid was noted within the abdomen/pelvis. (B) Color Doppler image clearly demonstrates the mixed echogenic septations and moderate color flow within them. (C) Doppler tracing of one of the color flow septations demonstrates an arterial waveform with very high diastolic flow within the mass (arrow). Findings are worrisome for malignancy.