1. Major Categories

A. Physiologic

(consistent with normal ovarian physiology)

B. Lesion

(Not consistent with normal ovarian physiology)

*Single compartment

*May contain ≥ 1 incomplete septum

3. Solid or solid-appearing lesions

A. External contour

Non-uniform outer margin

A lobulated outer margin is considered irregular

B. Internal contents

Acoustic shadowing 
(internal contents)

Artifact produced by attenuated echoes behind a sound absorbing structure; commonly seen with calcification or fibromatous lesion

4. Cystic lesions:

A. Internal margin or wall including solid component

Regular, uniform inner margin that may include inner margin of a solid component that is not a papillary projection

*Irregular, non-uniform inner margin. May include wall irregularities due to incomplete septations, solid components < 3 mm height, papillary projections, the contour of the solid component or the margin of any internal cystic area within the solid component

B. Internal content, cystic component

Anechoic fluid

No internal echoes or internal structures of any kind

Area of increased echogenicity relative to ovarian parenchyma without acoustic shadowing (seen with dermoid cysts or hemorrhagic lesions)

5. Vascularity

Color score = Overall subjective assessment of color Doppler flow within entire lesion (wall and/or internal component)

Color score = 1

No flow

Minimal Flow

Moderate Flow

Very strong Flow

6. General & Extra-Ovarian findings

Fluid descriptors

Cul-de-sac fluid

Ascites

Peritoneal thickening or nodules

O-RADS Score and Risk Category

Lesion Descriptors Examples

Pre-menopausal

Post-menopausal

2: Almost Certainly Benign [< 1%]

Simple cyst

Non-simple unilocular cyst, smooth inner margin

Follow up in 1 year
If concerning, US specialist or MRI

>3 cm but <10 cm

Follow up in 8-12 weeks
If concerning, US specialist

3. Low Risk Malignancy
[1-< 10%]

US specialist or MRI

Unilocular cyst, any size with irregular inner wall < 3 mm height

 

Multilocular cyst < 10 cm, smooth inner wall, color score = 1-3

Solid smooth, any size, color score = 1

4: Intermediate risk [10 – <50%]

Unilocular cyst with solid component: any size, 0-3 papillary projections, color score = any

US specialist or MRI

Multilocular cyst, no solid component

• ≥ 10cm, smooth inner wall, color score = 1-3
• Any size, smooth inner wall, color score = 4
• Any size, irregular inner wall and/or irregular septation, any color score

Multilocular cyst, with solid component: Any size, color score = 1-2

Solid, smooth, any size, color score = 2-3

5. High Risk [≥ 50%]

Unilocular cyst: any size, ≥ 4 papillary projections, color score = any

GYN oncologist

Multilocular cyst with solid component: any size, color score = 3-4

Solid smooth, any size, color score = 4

Solid irregular, any size, color score = any

Ascites and/or peritoneal nodules

Classic Benign Ovarian Lesions
US O-RADS 2 if < 10 cm
US O-RADS 3 if ≥ 10 cm 

*Reticular pattern: Fine thin intersecting lines representing fibrin strands
*Retracting clot: An avascular echogenic component with angular, straight, or concave margins

Pre-menopausal

*Hyperechoic component with acoustic shadowing
*Hyperechoic lines and dots
*Floating echogenic spherical structures

* Optional initial follow up in 8-12 weeks based on certainty

* If not removed, annual US follow up

*US specialist or MRI if interval change

*US specialist, gynecologist or MRI

* If not removed, annual US follow up

*Ground glass or homogeneous low-level echoes

Classic Benign Extra-Ovarian Lesions
US O-RADS 2: Any size

Simple cyst separated from the ovary that typically moves independent of the ovary when pressure is applied by the transducer

*If simple, none

Follows the contour of the adjacent pelvic organs or peritoneum, does not exert mass effect and typically contains septations. The ovary is either at the margin or suspended within the lesion

Incomplete septation, tubular
*Endosalpingeal folds: short round projections around the inner wall of a fluid distended tubular structure