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About O-RADS US

O-RADS US (Ovarian-Adnexal Reporting and Data System Ultrasound) is a standardized risk stratification system for adnexal masses based on ultrasound features.

Version used on the site: O-RADS US v2022: An Update from the American College of Radiology's Ovarian-Adnexal Reporting and Data System US Committee.

O-RADS US 0: Incomplete evaluation

O-RADS US 1: Normal ovary

O-RADS US 2: Almost certainly benign (<1%)

O-RADS US 3: Low risk (<10%)

O-RADS US 4: Intermediate risk (10–<50%)

O-RADS US 5: High risk (≥50%)

O-RADS US Categories

Credit: American College of Radiology (ACR) — O-RADS® (Ovarian-Adnexal Reporting and Data System). Color palette based on ACR material.

0

O-RADS US 0 — Incomplete Evaluation

Risk: Not assessable

The lesion features relevant to risk stratification cannot be accurately assessed due to technical factors.

Ultrasound findings

1
Illustration: Technical factors prevent adequate evaluation

Suggested management

Repeat ultrasound (US) or MRI

1

O-RADS US 1 — Normal Ovary

Risk: Normal

No ovarian lesion. Normal ovary.

Menopausal status

Ultrasound findings (Pre-menopause)

1
Illustration: No ovarian lesion
2

Suggested management (Pre-menopause)

No management needed

2

O-RADS US 2 — Almost Certainly Benign

Risk: <1%

Simple smooth unilocular cysts and classic benign lesions (hemorrhagic, dermoid, endometrioma, paraovarian, peritoneal inclusion cyst, hydrosalpinx).

Menopausal status

Simple cyst

Illustration: Simple cyst ≤3 cm

Smooth non-simple unilocular/bilocular cyst

Illustration: Smooth non-simple unilocular cyst (internal echoes and/or incomplete septations) or smooth bilocular cyst ≤3 cm
Illustration: Smooth non-simple unilocular cyst (internal echoes and/or incomplete septations) or smooth bilocular cyst 3 cm to <10 cm

Classic benign lesion

Illustration: Typical hemorrhagic cyst ≤ 5 cm
Illustration: Typical hemorrhagic cyst > 5 cm and < 10 cm
Illustration: Typical dermoid cyst < 10 cm
3

O-RADS US 3 — Low Risk of Malignancy

Risk: <10%

Typically benign ovarian lesions ≥10 cm and other low-risk findings (large smooth cysts, irregular inner wall <3 mm, multilocular <10 cm with smooth wall, solid lesions with smooth surface).

Typically benign ovarian lesions ≥ 10 cm

1
Illustration: Typical hemorrhagic cyst ≥ 10 cm
2
3

Other lesions

1
Illustration: Smooth unilocular cyst ≥ 10 cm (simple or non-simple)
2
3
Illustration: Unilocular cyst of any size with irregular inner wall < 3 mm in height
4
Illustration: Multilocular cyst < 10 cm, smooth inner wall, color score (CS) = 1–3
5
Illustration: Solid lesion, with or without shadowing, smooth surface, any size, CS = 1
6

Suggested management

If not surgically removed, consider follow-up US at 6 months. In some scenarios, shorter imaging follow-up may be considered (e.g., clinical factors). During follow-up: • If smaller (≥10–15% decrease in average linear dimension), no further surveillance. • If stable, follow-up US at 24 months from the initial exam. • If enlarging (≥10–15% increase in average linear dimension), consider follow-up US at 12 and 24 months from the initial exam, then manage per gynecology. • For changing morphology, reassess using lexicon descriptors. • Clinical management with gynecology as needed. • For solid lesions, consider specialist US (if available) or MRI (with O-RADS MRI score).

4

O-RADS US 4 — Intermediate Risk

Risk: 10-<50%

Multilocular cyst without solid component ≥10 cm or with CS = 4, unilocular/multilocular cyst with a solid component, solid lesion with smooth surface and CS = 2–3.

Bilocular cyst without solid component

1

Multilocular cyst without solid component

1
Illustration: Multilocular cyst without solid component: ≥ 10 cm, smooth inner wall, CS = 1–3
2
Illustration: Multilocular cyst without solid component: any size, smooth inner wall, CS = 4
3
Illustration: Multilocular cyst without solid component: any size, irregular inner wall, any CS
4
Illustration: Multilocular cyst without solid component: any size, irregular septation, any CS

Unilocular cyst with solid component

1
Illustration: Unilocular cyst with solid component, any size, any CS
2
Illustration: Unilocular cyst with 0–3 papillary projections, any CS

Multilocular cyst with solid component

1
Illustration: Multilocular cyst with solid component, any size, CS = 1–2

Solid lesion

1
Illustration: Solid lesion, smooth surface, any size, CS = 2–3

Suggested management

Imaging options include specialist US (if available) and MRI (with O-RADS MRI score), per gynecologic oncologist protocol. Management by gynecology with consultation with gynecologic oncology or directly by gynecologic oncology.

5

O-RADS US 5 — High Risk

Risk: ≥50%

Unilocular cyst with ≥4 papillary projections, multilocular cyst with solid component and CS = 3–4, solid lesion with CS = 4 or irregular surface, ascites and/or peritoneal nodules.

Unilocular cyst (papillae)

1
Illustration: Unilocular cyst, any size, ≥ 4 papillary projections, any CS

Multilocular cyst with solid component

1
Illustration: Multilocular cyst with solid component, any size, CS = 3–4

Solid lesion

1
Illustration: Solid lesion with smooth surface, any size, CS = 4
2
Illustration: Solid lesion with irregular surface, any size, any CS

Additional findings

1
Illustration: Peritoneal implants and/or ascites

Suggested management

Management by gynecologic oncology

Glossary

Smooth and irregular

refer to inner walls/septation(s) for cystic lesions, and outer contour for solid lesions; irregular inner wall for cysts = <3 mm in height

Shadowing

must be diffuse or broad to qualify; excludes refractive artifact

CS

color score; degree of intralesional vascularity; 1 = none, 2 = minimal flow, 3 = moderate flow, 4 = very strong flow

Solid

excludes blood products and dermoid contents; solid lesion = ≥80% solid; solid component = protrudes ≥3 mm (height) into cyst lumen off wall or septation

PP

papillary projection; subtype of solid component surrounded by fluid on 3 sides

Bilocular / multilocular

Bilocular = 2 locules; multilocular = ≥3 locules; bilocular smooth cysts have a lower risk of malignancy, regardless of size or CS

References

Strachowski LM, Jha P, Phillips CH, Blanchette Porter MM, Froyman W, Glanc P, Guo Y, Patel MD, Reinhold C, Suh-Burgmann EJ, Timmerman D, Andreotti RF. O-RADS US v2022: An Update from the American College of Radiology's Ovarian-Adnexal Reporting and Data System US Committee. Radiology. 2023 Sep;308(3):e230685. doi: 10.1148/radiol.230685. PMID: 37698472.

Andreotti RF, Timmerman D, Strachowski LM, Froyman W, Benacerraf BR, Bennett GL, Bourne T, Brown DL, Coleman BG, Frates MC, Goldstein SR, Hamper UM, Horrow MM, Hernanz-Schulman M, Reinhold C, Rose SL, Whitcomb BP, Wolfman WL, Glanc P. O-RADS US Risk Stratification and Management System: A Consensus Guideline from the ACR Ovarian-Adnexal Reporting and Data System Committee. Radiology. 2020 Jan;294(1):168-185. doi: 10.1148/radiol.2019191150. Epub 2019 Nov 5. PMID: 31687921.