Adnexal Lesions: O-RADS US
Authors: Yang Guo, MD, Jessie Chai, MD, Carol Benson, MD, Atul Shinagare, MD
Date: June 5, 2025
Category | Term | Definition | Example |
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1. Major Categories A. Physiologic (consistent with normal ovarian physiology) |
Follicle | Simple cyst ≤ 3 cm in premenopausal women | ![]() |
Corpus luteum (CL) | Thick-walled cyst typically ≤3 cm, ± crenulated inner walls, ± internal echoes, with peripheral flow in premenopausal group. May be solid appearing with peripheral flow in premenopausal women | ![]() |
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B. Lesion (Not consistent with normal ovarian physiology) |
Unilocular, without solid component(s) |
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Unilocular cyst with solid component(s) | As above, but includes solid tissue ≥ 3 mm in height | ![]() |
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Bilocular, without solid component(s) |
Cystic lesion with 2 locules (single complete septation) ± internal echoes, incomplete septa, or wall/septal irregularity (< 3 mm height) |
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Bilocular, with solid component(s) |
As above and includes solid tissue ≥ 3 mm in height | ![]() |
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Multilocular cyst, without solid component(s) |
Cystic lesion with ≥ 3 locules (≥ 2 complete septations) | ![]() |
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Multilocular cyst with solid component(s) | As above and includes solid tissue ≥ 3 mm in height | ![]() |
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Solid or solid appearing (≥80%) |
Lesion with at least 80% solid tissue (based on echogenicity and echotexture)
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2. Size | Maximum diameter |
Maximal diameter of the lesion in any plane
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Average linear dimension |
(Maximum length + height + width)/3
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3. Solid or solid-appearing lesions A. External contour |
Smooth | Uniform/even outer margin | ![]() |
Irregular |
Non-uniform/uneven outer margin, includes lobulated |
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B. Shadowing |
Broad or diffuse |
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4. Cystic lesions: A. Inner Walls or Septations |
Smooth | Uniform/even inner margin or septation | ![]() |
Irregular |
Non-uniform/uneven inner margin or septation
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Calcifications |
High-level echogenicity within wall associated with posterior shadowing
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B. Internal content |
Hemorrhagic cyst descriptors |
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Dermoid cyst descriptors |
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Endometrioma descriptors |
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Septations |
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C. Solid or Solid-appearing component |
Solid component |
Focal wall thickening or solid tissue arising from cyst wall/septation that protrudes into cyst cavity ≥ 3 mm in height
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Papillary projection |
Solid component whose height ≥ 3mm, arise from cyst wall or septation and protrudes into the cyst cavity |
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5. Vascularity Color score (CS) = Overall subjective assessment of color Doppler flow within entire lesion (wall and/or internal component) |
CS = 1 |
No flow |
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CS = 2 |
Minimal Flow |
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CS = 3 |
Moderate Flow |
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CS = 4 |
Very strong Flow |
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6. General & Extra-Ovarian findings |
Paraovarian cyst |
Simple cyst separate from the adjacent ovary, includes paratubal cyst Moves independent of ovary with transducer pressure |
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Peritoneal inclusion cyst |
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Hydrosalpinx |
Anechoic, fluid-filled tubular structure
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Physiologic fluid |
Confined to pouch of Douglas and below uterine fundus when anteverted/anteflexed or between uterus and urinary bladder when retroverted/retroflexed |
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Ascites |
Fluid extends beyond pouch of Douglas or cul-de-sac and above uterine fundus when anteverted/anteflexed, and anterior/superior to uterus when retroverted/retroflexed |
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Peritoneal nodules |
Nodularity or focal thickening of the peritoneal lining or along the serosal surface of bowel |
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Utilizing O-RADS US Lexicon to Determine the Category of an Ovarian or Fallopian Tubal Lesion
- Major categories: A. (Physiologic) or B. (Lesion)
- Size: Maximal diameter
- Solid or solid appearing lesions:
- A. External contour (smooth or irregular?)
- B. Posterior Acoustic Features (broad, diffuse or absent?)
- Cystic lesions:
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- A. Inner margins or walls: Is the inner wall smooth or irregular? Any solid components or any papillary projections (if so, how many)?
- B. Internal content, cystic component
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- Vascularity: No flow, minimal flow, moderate flow or very strong flow (make sure scale for color is as low as possible while avoiding artifact)
- General and extra-ovarian findings: Free fluid (cul-de-sac fluid or ascites) and other (peritoneal thickening or nodule)
O-RADS Score | Risk Category | Lesion Descriptors Examples | Management | ||
Pre-menopausal | Post-menopausal | ||||
0 | Incomplete Evaluation | Lesion features relevant for risk stratification cannot be accurately characterized due to technical factors | Repeat US study or MRI | ||
1 | Normal Ovary | No ovarian lesion | None | ||
Physiologic cyst: follicle (≤ 3 cm) or corpus luteum (typically ≤3 cm) | |||||
2 | Almost Certainly Benign [< 1%] | Simple cyst![]() | ≤3 cm | None | Follow up in 1 year |
>3 cm to 5 cm | None | Follow up in 1 year | |||
>5 cm but <10 cm | Follow up US in 1 year | ||||
Unilocular, smooth, non-simple cyst (inner echoes and/or incomplete septations)![]() ——- Bilocular, smooth cyst | ≤3 cm | None | Follow up in 1 year | ||
>3 cm but < 10 cm | Follow up in 6 months | ||||
Typical benign ovarian lesion (Section 3) | < 10 cm | See separate table for descriptors and management | |||
Typical benign extraovarian lesion (Section 3) | Any size | ||||
3 | Low Risk Malignancy [1-< 10%] | Typical benign ovarian lesion, ≥ 10 cm (Section 3) | Imaging:
Clinical: Gynecologist | ||
Unilocular or bilocular cyst, smooth, ≥ 10 cm | |||||
Unilocular cyst, irregular, any size![]() | |||||
Multilocular cyst, smooth, < 10 cm, CS < 4![]() | |||||
Solid lesion, ± shadowing, smooth, any size, CS = 1![]() | |||||
Solid lesion, shadowing, smooth, any size, CS 2–3 | |||||
4 | Intermediate risk [10 – <50%] | Bilocular cyst without solid component(s): irregular, any size, any CS | Imaging: Options include:
Clinical: Gynecologist with gyn-oncologist consultation or solely by gyn-oncologist | ||
Multilocular cyst, no solid component
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Unilocular cyst with solid components
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Bi- or multilocular cyst, with solid component(s): Any size, CS = 1-2![]() | |||||
Solid, non-shadowing: Smooth, any size, CS = 2-3![]() | |||||
5. | High Risk [≥ 50%] | Unilocular cyst, ≥ 4 pps, any size, CS = any![]() | Imaging: Per gyn-oncologist consultation Clinical: Gyn-oncologist | ||
Bi- or multilocular cyst with solid component(s), any size, CS = 3-4![]() | |||||
Solid, smooth, ± shadowing, any size, CS = 4![]() | |||||
Solid irregular, any size, color score = any![]() | |||||
Ascites and/or peritoneal nodules![]() |
Note:
CS = color score; pp = papillary projection
Postmenopausal = ≥1 year amenorrhea (early: <5 yrs; late: ≥5 yrs); if uncertain or uterus surgically absent, use age >50 years (early ≥50 yrs but <55 yrs, late ≥55 yrs)
Lesion | Descriptors and Definitions For any atypical features on initial or follow-up exam, use other lexicon descriptors (eg, unilocular, multilocular, solid etc) | Management If sonographic features are only suggestive, and overall assessment is uncertain, consider follow-up US within 3 months |
Typical hemorrhagic cyst | Unilocular cyst, no internal vascularity*, and at least one of the following:
———-
| Imaging:
Clinical: Gynecologist as needed |
Typical Dermoid cyst | Cystic lesion ≤ 3 locules, no internal vascularity, and at least one of the following:
| Imaging:
Clinical: Gynecologist as needed |
Typical endometrioma | Cystic lesion with ≤ 3 locules, no internal vascularity, homogeneous low-level/ground glass echoes, and smooth inner walls/septation(s): ± peripheral punctate echogenic foci in wall | Imaging:
Clinical: Gynecologist as needed |
Typical para-ovarian cyst | Simple cyst separated from the ovary![]() | Imaging: None Clinical: Gynecologist as needed |
Typical Peritoneal Inclusion cyst | Fluid collection with ovary at margin or suspended within that conforms to adjacent pelvic organs: ±septations (representing adhesions)
| Imaging: None Clinical: Gynecologist as needed |
Typical hydrosalpinx | Anechoic, fluid-filled tubular structure
| Imaging: None Clinical: Gynecologist as needed |
*Excludes vascularity in walls or intervening septation(s)
- 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.