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
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
B. Lesion (Not consistent with normal ovarian physiology)	Unilocular, without solid component(s)	Single locule (no complete septation) May contain ≥ 1 incomplete septum ± internal echoes, incomplete septa, wall irregularity < 3 mm in height
	Unilocular cyst with solid component(s)	As above, but includes solid tissue ≥ 3 mm in height
	Bilocular, without solid component(s)	Cystic lesion with 2 locules (single complete septation) ± internal echoes, incomplete septa, or wall/septal irregularity (< 3 mm height)
	Bilocular, with solid component(s)	As above and includes solid tissue ≥ 3 mm in height
	Multilocular cyst, without solid component(s)	Cystic lesion with ≥ 3 locules (≥ 2 complete septations)
	Multilocular cyst with solid component(s)	As above and includes solid tissue ≥ 3 mm in height
	Solid or solid appearing (≥80%)	Lesion with at least 80% solid tissue (based on echogenicity and echotexture) ± internal vascularity May use term solid-appearing if no internal vascularity
2. Size	Maximum diameter	Maximal diameter of the lesion in any plane Used for risk stratification
2. Size	Average linear dimension	(Maximum length + height + width)/3 Used to assess interval change
3. Solid or solid-appearing lesions A. External contour	Smooth	Uniform/even outer margin
	Irregular	Non-uniform/uneven outer margin, includes lobulated
B. Shadowing	Broad or diffuse	Associated with calcifications and fibromatous lesions Relevant for solid smooth Differs from refractive artifact
4. Cystic lesions: A. Inner Walls or Septations	Smooth	Uniform/even inner margin or septation
	Irregular	Non-uniform/uneven inner margin or septation Focal wall or septal thickening < 3 mm in height
	Calcifications	High-level echogenicity within wall associated with posterior shadowing Risk assessment based upon smooth or irregular margin
B. Internal content	Hemorrhagic cyst descriptors	Unilocular, no internal echoes Reticular pattern: fine, thin intersecting lines Retractile clot: avascular component with echogenicity higher than adjacent fluid and angular, straight, or concave margins
	Dermoid cyst descriptors	Hyperechoic component (diffuse or regional) with shadowing Hyperechoic lines and dots Floating echogenic spherical structures
	Endometrioma descriptors	≤ 3 locules, no internal vascularity, may have flow in walls or intervening septa Homogeneous low-level internal echoes: ground glass echoes Peripheral punctate echogenic foci represent hemosiderin byproducts, highly characteristic albeit uncommon
	Septations	Complete: linear tissue within cyst cavity extending from wall to wall in all planes Incomplete: linear tissue within cyst cavity not extending from wall to wall in all planes
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 Excludes blood products and dermoid cyst contents May use term solid-appearing if no internal vascularity
C. Solid or Solid-appearing component	Papillary projection	Solid component whose height ≥ 3mm, arise from cyst wall or septation and protrudes into the cyst cavity
5. Vascularity Color score (CS) = Overall subjective assessment of color Doppler flow within entire lesion (wall and/or internal component)	CS = 1	No flow
	CS = 2	Minimal Flow
	CS = 3	Moderate Flow
	CS = 4	Very strong Flow
6. General & Extra-Ovarian findings	Paraovarian cyst	Simple cyst separate from the adjacent ovary, includes paratubal cyst Moves independent of ovary with transducer pressure
	Peritoneal inclusion cyst	Fluid collection with ovary at margin or suspended within that conforms to adjacent pelvic organs ± septations representing adhesions
	Hydrosalpinx	Anechoic, fluid-filled tubular structure Incomplete septation(s): internal linear tissue that does not extend from wall to wall in all planes Endosalpingeal folds: short round projections around inner walls of fluid-filled tube often equidistantly spaced
	Physiologic fluid	Confined to pouch of Douglas and below uterine fundus when anteverted/anteflexed or between uterus and urinary bladder when retroverted/retroflexed
	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
	Peritoneal nodules	Nodularity or focal thickening of the peritoneal lining or along the serosal surface of bowel

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:
- - 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
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)

US O-RADS Categories

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: If not surgically excised, consider follow up US within 6 months. If solid, may consider US specialist (if available) or MRI (with O-RADS MRI score) 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: US specialist (if available) or MRI (with O-RADS MRI score) or Per gyn-oncologist protocol Clinical: Gynecologist with gyn-oncologist consultation or solely by gyn-oncologist
		Multilocular cyst, no solid component Smooth, ≥ 10cm, CS < 4 —————————– Smooth, any size, CS = 4 —————————– Irregular, any size any CS
		Unilocular cyst with solid components < 4 pps or solid component(s) not considered a pp; any size
		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)

Classic Benign Ovarian and Extra-Ovarian Lesions

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:

Reticular pattern (fine, thin intersecting lines representing fibrin strands)

———-

Retractile clot (intracystic component with straight, concave or angular margins)

Imaging:

Pre-menopausal
- ≤5cm: None
- >5 cm but < 10 cm: follow up US in 2-3 months
Early postmenopausal (< 5 years)
- <10 cm, options to confirm include: follow-up US in 2-3 months or US specialist or MRI
Late postmenopausal (≥5years): should not occur; recategorize using other lexicon descriptors.

Clinical: Gynecologist as needed

Typical Dermoid cyst

Cystic lesion ≤ 3 locules, no internal vascularity, and at least one of the following:

Hyperechoic component(s) (diffuse or regional) with shadowing

———-

Hyperechoic lines and dots

———-

Floating echogenic spherical structure

Imaging:

≤3 cm: May consider follow-up US in 12 months
> 3 cm but < 10cm: if not surgically excised, follow-up US in 12 months

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:

Premenopausal: < 10 cm: if not surgically excised, follow-up US in 12 months
Postmenopausal: < 10 cm and initial exam, options to confirm include: follow-up US in 2-3 months or US specialist or MRI. Then, if not surgically excised, recommend follow-up US in 12 months

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

±Incomplete septation(s) (representing folds
±Endosalpingeal folds (short, round projections around inner walls)

Imaging: None

Clinical: Gynecologist as needed

*Excludes vascularity in walls or intervening septation(s)

Reference

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.