How to Use O-RADS US v2022: A Systematic Approach to Adnexal Lesions

How to Use O-RADS US v2022

O-RADS US was developed to describe ovarian and adnexal ultrasound findings using a shared lexicon, convert imaging features into a malignancy-risk category, and make management recommendations more consistent. Version 2022 clarified the scope of the system and several definitions, including the distinction between bilocular and multilocular cysts, acoustic shadowing in solid lesions, and management recommendations.

O-RADS recommendations provide clinical support for average-risk patients without acute symptoms. Management should be individualized in the setting of acute pain, suspected torsion, pregnancy, known malignancy, high genetic risk, or another specific clinical scenario.

Ask the right first question: Is there a lesion?

Before entering the O-RADS algorithm, determine which of these three groups the image belongs to:

1. Normal ovary or physiologic cyst
2. Typical classic benign lesion
3. Another cystic, solid, or solid-appearing lesion

This distinction matters because classic benign lesions such as a typical hemorrhagic cyst, dermoid, or endometrioma do not enter the general morphology algorithm from the beginning when no atypical feature is present.

What do the categories mean?

These risk ranges are not histopathologic diagnoses. They are risk estimates based on the lesion's imaging phenotype.

1. Is the lesion cystic or solid?

In O-RADS US v2022, a solid component is tissue that protrudes at least 3 mm into the cyst lumen from the wall or a septation. Blood products and dermoid contents are not considered solid tissue. A papillary projection is a subtype of solid component surrounded by fluid on three sides.

A solid or solid-appearing lesion is one in which approximately 80% or more of the lesion is solid. This distinction determines which branch of the algorithm uses features such as color score and acoustic shadowing.

2. Name the number of locules correctly

One practical change in v2022 is the following terminology:

• Unilocular: one cavity
• Bilocular: two locules
• Multilocular: three or more locules

A cyst with a single smooth septation and a size under 10 cm may be classified as O-RADS 2 when the other criteria are met. Calling every septated cyst “multilocular” out of habit may lead to unnecessary category escalation.

3. Assess the wall and septations

In cystic lesions, smoothness is assessed using the inner wall and septations. In solid lesions, the outer contour is assessed. Apparent irregularity should not merely reflect the imaging angle. Use multiple planes and adequate magnification.

An irregular wall or septation, a solid component, and papillary projections are among the key features that increase malignancy risk.

4. Standardize the color score

O-RADS US grades intralesional vascularity on four levels:

• Color score 1: No flow
• Color score 2: Minimal flow
• Color score 3: Moderate flow
• Color score 4: Very strong flow

This assessment depends on equipment settings. The color score is unreliable when the pulse repetition frequency, wall filter, or gain is inappropriate. Although identical settings may not be feasible in every case, Doppler technique must be optimized to demonstrate low-velocity flow.

5. Interpret acoustic shadowing correctly

Broad or diffuse acoustic shadowing in a solid lesion may support fibromatous content and is used in the v2022 algorithm as a feature that improves specificity. Edge-refraction artifact is not true shadowing. Confirm in more than one plane that the shadow originates broadly from the lesion.

6. Recognize classic benign lesions

When the appearance is typical, the following may fall within the classic benign group:

• Hemorrhagic cyst
• Dermoid cyst
• Endometrioma
• Paraovarian cyst
• Peritoneal inclusion cyst
• Hydrosalpinx

The word “typical” is essential. If there is a new solid component, definite internal vascularity, an irregular wall, or unexpected growth, do not leave the lesion under a classic benign label. Reassess it using the other lexicon descriptors.

Why do ascites and peritoneal nodules matter?

Ascites and/or peritoneal nodules that cannot be explained by another benign or malignant cause may upgrade an associated O-RADS 3 or 4 lesion to O-RADS 5. Heart failure, cirrhosis, infection, and other causes must be considered. Ascites in a patient with a small O-RADS 1–2-appearing lesion does not automatically indicate ovarian malignancy.

Example case 1: Low-risk cystic lesion

Findings: In a premenopausal patient, a 6.2 cm smoothly marginated bilocular cystic lesion in the right ovary, without a solid component or internal vascularity.

Under v2022, this morphology is assessed as a smooth bilocular cyst. The final category and follow-up recommendation should be confirmed using the official management table, together with lesion size, menopausal status, and clinical context.

Example reporting language:

In the right ovary, there is a 62 mm bilocular cystic lesion with smooth inner walls, no solid component or papillary projection, and no internal vascularity on Doppler imaging. The morphology is low risk according to the O-RADS US v2022 lexicon. The category and follow-up recommendation have been assigned according to the patient's menopausal status and the current O-RADS management table.

Example case 2: Cyst with a solid component

Findings: An 8 cm unilocular cyst containing three papillary projections, with definite but not maximal vascularity within the papillary structures.

In a unilocular cyst, the number of papillary projections and their vascularity are major determinants of risk category. A lesion with fewer than four papillary projections may enter the O-RADS 4 branch depending on the other features; four or more papillary projections support a higher-risk category. The final classification must be checked against the official algorithm.

Minimum elements of the report

Whenever possible, an adnexal lesion report should explicitly document:

• Laterality and organ of origin
• Three dimensions
• Cystic/solid composition and number of locules
• Inner-wall and septal smoothness
• Solid component and number of papillary projections
• Color score
• Acoustic shadowing
• Ascites/peritoneal nodules
• O-RADS category
• Management recommendation according to menopausal status

Common mistakes made by residents

1. Mistaking a blood clot for a solid component

Reticular fibrin strands and a retracting clot with concave margins favor a hemorrhagic cyst. When uncertain, use Doppler and follow-up findings.

2. Reporting a cyst with one septation as multilocular

In v2022, two locules are called “bilocular”; three or more are “multilocular.”

3. Assigning a color score without optimizing Doppler settings

Technically inadequate Doppler may produce a falsely low color score.

4. Treating every shadow as a benign feature

Edge refraction is not true broad or diffuse acoustic shadowing.

5. Reporting the category without the morphology

The category should be auditable. The report must contain the findings that led to it.

6. Giving a management recommendation without considering age and menopausal status

The follow-up approach for the same morphology may differ according to menopausal status.

Workstation checklist

1. Is the lesion ovarian or extraovarian in origin?
2. Is it physiologic or does it have a typical classic benign appearance?
3. Did I use the v2022 definition for the number of locules?
4. Did I clearly document the solid component and the number of papillary projections?
5. Were the Doppler settings adequate for assigning the color score?
6. Is there ascites or a peritoneal nodule, and could it have another explanation?
7. Are the category and recommendation consistent with menopausal status?

Frequently asked questions

Does O-RADS 3 mean suspected cancer?

O-RADS 3 is a low-risk category, with an estimated malignancy risk from 1% to less than 10%. Management depends on lesion type, size, menopausal status, and clinical context.

Can O-RADS be used in acute pelvic pain?

The morphological lexicon may be helpful, but management recommendations were designed for average-risk patients without acute symptoms. Emergencies such as torsion or rupture have separate clinical priority.

Are O-RADS MRI and O-RADS US the same category system?

No. The systems are complementary but use different imaging features and risk models. Ultrasound is the first-line test for most patients, whereas MRI is a problem-solving method for selected indeterminate lesions.

References

1. American College of Radiology. O-RADS Ultrasound. Source (opens in a new tab)
2. American College of Radiology. O-RADS Ultrasound v2022 Assessment Categories Algorithm. Source (opens in a new tab)
3. Strachowski LM, Jha P, Chawla TP, et al. O-RADS US v2022: An Update from the American College of Radiology's Ovarian-Adnexal Reporting and Data System US Committee. Radiology. 2023. Source (opens in a new tab)
4. Andreotti RF, Timmerman D, Strachowski LM, et al. O-RADS US Risk Stratification and Management System: A Consensus Guideline. Radiology. 2020;294(1):168–185. Source (opens in a new tab)