RadAsist is a platform developed for radiology education and reference. AI-powered suggestions (differential diagnosis, image analysis, chat) are assistive tools and do not replace clinical judgment. Final diagnosis and treatment decisions should always be made by qualified healthcare professionals.

RadAsist—From findings to diagnosis, from diagnosis to report

Privacy Policy Contact© 2026 RadAsist

Classifications

O-RADS MRI

2020ACR

Ovarian-Adnexal Reporting and Data System (MRI)

Classifies the malignancy risk of ovarian and adnexal lesions based on MRI features. O-RADS MRI categories 1-5 are determined.

Categories

1Normal0% malignancy

Normal ovary/adnexal structure

Physiologic follicle
Corpus luteum
Normal ovarian size

Management: Routine follow-up

2Benign<1% malignancy

Almost certainly benign lesion

Simple cyst (>=3cm premenopausal, any size postmenopausal)
Endometrioma (typical T1 hyperintense, T2 shading)
Mature cystic teratoma (fat-fluid level)
Hemorrhagic cyst (typical)

Management: No follow-up or routine US follow-up

3Low risk<5% malignancy

Low risk of malignancy

Uni/multilocular cystic, no solid component
Thin (<3mm) smooth wall/septa
T2 hypointense + T2 hyperintense structures together
Smooth solid lesion, T2 hypointense (fibroma)

Management: US follow-up or MR follow-up

4Intermediate riskIntermediate risk (~50%)

Intermediate risk of malignancy

Enhancing solid component (smooth, <1cm)
Enhancing papillary projection
Irregular septa (>=3mm)
No peritoneal/omental nodularity

Management: Gynecologic oncology consultation; surgical planning

5High riskHigh risk (>90%)

High risk of malignancy

Irregular enhancing solid component (>=1cm)
Peritoneal/omental nodularity or thickening
Ascites + solid adnexal mass
Invasion signs

Management: Gynecologic oncology consultation; surgery (staging)

References

Thomassin-Naggara I, et al. Ovarian-Adnexal Reporting Data System Magnetic Resonance Imaging (O-RADS MRI) Score for Risk Stratification. JAMA Netw Open 2020;3(1):e1919896.
ACR O-RADS MRI Risk Stratification System, 2020.

This classification system is intended for clinical decision support. Final diagnosis and treatment decisions rest with the clinician.