Adnexal Lesions: O-RADS US

Authors: Yang Guo, MDJessie Chai, MDCarol Benson, MDAtul Shinagare, MD

Date: June 5, 2025

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Category Term Definition Example

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, without solid component(s)

Bilocular, with solid component(s)

As above and includes solid tissue ≥ 3 mm in height Bilocular, with solid component(s)

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 
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 Inner Walls or Septations Smooth

Irregular

Non-uniform/uneven inner margin or septation

  • Focal wall or septal thickening < 3 mm in height

Inner Walls or Septations Irregular

Calcifications

High-level echogenicity within wall associated with posterior shadowing

  • Risk assessment based upon smooth or irregular margin 

Cystic lesions, Inner Walls or Septations, Calcifications

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
Internal content Endometrioma descriptors

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

Internal Content Separations

Internal Content Sepatations

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
Solid component
Papillary projection

Solid component whose height ≥ 3mm, arise from cyst wall or septation and protrudes into the cyst cavity

Solid Conpoment Papillary projection

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

Ovarian findings Peritoneal inclusion cyst

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
Ovarian findings Hydrosalpinx
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

  1. Major categories: A. (Physiologic) or B. (Lesion)
  2. Size: Maximal diameter
  3. Solid or solid appearing lesions:
    • A. External contour (smooth or irregular?)
    • B. Posterior Acoustic Features (broad, diffuse or absent?)
  4. 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 
  5. Vascularity: No flow, minimal flow, moderate flow or very strong flow (make sure scale for color is as low as possible while avoiding artifact)
  6. General and extra-ovarian findings: Free fluid (cul-de-sac fluid or ascites) and other (peritoneal thickening or nodule)
O-RADS ScoreRisk Category

Lesion Descriptors Examples

Management
Pre-menopausalPost-menopausal
0Incomplete EvaluationLesion features relevant for risk stratification cannot be accurately characterized due to technical factorsRepeat US study or MRI
1Normal OvaryNo ovarian lesionNone
Physiologic cyst: follicle (≤ 3 cm) or corpus luteum (typically ≤3 cm)
2Almost Certainly Benign [< 1%]Simple cyst
≤3 cmNoneFollow up in 1 year
>3 cm to 5 cmNoneFollow up in 1 year
>5 cm but <10 cmFollow up US in 1 year
Unilocular, smooth, non-simple cyst (inner echoes and/or incomplete septations)

——- Bilocular, smooth cyst
≤3 cmNoneFollow up in 1 year
>3 cm but < 10 cmFollow up in 6 months
Typical benign ovarian lesion (Section 3)< 10 cmSee separate table for descriptors and management
Typical benign extraovarian lesion (Section 3)Any size
3Low 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
4Intermediate 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)

LesionDescriptors 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 cystSimple 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)

  1. 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.
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