The O-RADS system is system for standardised reporting of ovarian and adnexal imaging. It is part of a family of reporting and data systems (RADS) published by the American College of Radiology
O-RADS was initially designed for sonographic study only, but was later extended to include MRI. The system outlines six risk categories, O-RADS (US or MRI) 0-6. Strictly speaking O-RADS 0 denotes an incomplete or inconclusive study so 5 risk categories is perhaps more accurate.
- O-RADS 0: Incomplete evaluation
- O-RADS 1: Normal ovary
- O-RADS 2: Almost certainly benign (<1% risk of malignancy)
- O-RADS 3: Low risk (1-9% risk of malignancy)
- O-RADS 4: Intermediate risk (10-49% risk of malignancy)
- O-RADS 5: High risk (>50% risk of malignancy)
O-RADS (US)
O-RADS US 1
Physiological; follicle or corpus luteum ≤3cm.
O-RADS US 2
- Simple cysts or non-simple smooth unilocular or bilocular cysts <10cm.
- So called classical benign lesions <10cm (or any size for extraovarian lesions).
O-RADS US 3
- Cysts or classical benign lesions ≥10cm.
- Smooth multilocular cysts <10cm without very strong doppler flow.
- Some solid lesions with shadowing and without strong doppler flow.
O-RADS 4
- Irregular bilocular cysts without solid components
- Multilocular cysts ≥10cm without strong doppler flow, or those or any size with very strong doppler flow.
- Cysts with solid components and minimal doppler flow.
- Solid, non-shadowing lesions without strong doppler flow.
O-RADS 5
- Everything else…
- Unilocular cysts with ≥ papillary projections or solid components.
- Bilocular or multilocular cysts with solid components and strong doppler flow.
- Solid lesions with strong doppler flow or irregularity
- Ascites
- Peritoneal nodules