Table 2.
O-RADS MRI Risk Stratification and Management System.
| O-RADS MRI Score | Risk Category | Positive Predictive Value for Malignancy | Lexicon Description |
|---|---|---|---|
| 0 | Incomplete evaluation | N/A | N/A |
| 1 | Normal ovaries | N/A | No ovarian lesion |
| Follicle defined as simple cyst ≤ 3 cm in a premenopausal woman | |||
| Hemorrhagic cyst ≤ 3 cm in a premenopausal woman | |||
| Corpus luteum +/− hemorrhage ≤ 3 cm in a premenopausal woman | |||
| 2 | Almost certainly benign | <0.5% | Cyst: Unilocular- any type of fluid content - No wall enhancement - No enhancing solid tissue * |
| Cyst: Unilocular–simple or endometriotic fluid content -Smooth enhancing wall -No enhancing solid tissue | |||
| Lesion with lipid content ** - No enhancing solid tissue | |||
| Lesion with solid tissue showing dark signal on T2/DWI -Homogeneously hypointense on T2 and DWI | |||
| Dilated fallopian tube-simple fluid content - Thin, smooth wall/endosalpingeal folds with enhancement - No enhancing solid tissue | |||
| Para-ovarian cyst–any type of fluid - Thin, smooth wall +/− enhancement - No enhancing solid tissue | |||
| 3 | Low risk | ~5% | Cyst: Unilocular–proteinaceous, hemorrhagic or mucinous fluid content - Smooth enhancing wall - No enhancing solid tissue |
| Cyst: Multilocular-Any type of fluid, no lipid content - Smooth septae and wall with enhancement-No enhancing solid tissue | |||
| Lesion with solid tissue (excluding T2 dark/DWI dark) - Low risk time intensity curve on DCE MRI | |||
| Dilated fallopian tube - Non-simple fluid: Thin wall/folds - Simple fluid: Thick, smooth wall/folds - No enhancing solid tissue | |||
| 4 | Intermediate risk | ~50% | Lesion with solid tissue (excluding T2 dark/DWI dark) - Intermediate risk time intensity curve on DCE MRI - If DCE MRI is not feasible, score 4 is any lesion with solid tissue (excluding T2 dark/DWI dark) that is enhancing ≤ myometrium at 30–40 s on non-DCE MRI |
| Lesion with lipid content - Large volume enhancing solid tissue | |||
| 5 | High risk | ~90% | Lesion with solid tissue (excluding T2 dark/DWI dark) - High risk time intensity curve on DCE MRI - If DCE MRI is not feasible, score 5 is any lesion with solid tissue (excluding T2 dark/DWI dark) that is enhancing > myometrium at 30–40 s on non-DCE MRI |
| Peritoneal, mesenteric or omental nodularity or irregular thickening with or without ascites |
* Solid tissue: a lesion component that enhance and conforms to one of the following morphologies: mural nodule, papillary projection, irregular wall/septation or other larger solid portions. ** Minimal enhancement of Rokitansky nodules in lesion containing lipid does not change to O-RADS MRI 4 DCE = dynamic contrast enhancement with a time resolution of 15 s or less, DWI = diffusion weighted images, MRI = magnetic resonance imaging, N/A = not applicable.