O-RADS Calculator

Ovarian-Adnexal Reporting and Data System - ACR risk stratification

1 Select Imaging Modality
Patient Status
2 Lesion Characteristics (US)
Lesion Type
Inner Wall/Septation
Solid Component
3 High-Risk Features
2 Lesion Characteristics (MRI)
Lesion Type
Fluid Content
Wall Enhancement
Enhancing Solid Tissue
Papillary projection, mural nodule, irregular wall/septa, or larger solid portion
4 High-Risk Features

About O-RADS

The Ovarian-Adnexal Reporting and Data System (O-RADS) is an ACR-developed risk stratification system that standardizes reporting and management of adnexal masses. It provides consistent terminology and evidence-based malignancy risk estimates.

O-RADS Scoring Overview

Score US Risk MRI Risk Management
1 Normal Normal/Physiologic Routine care
2 <1% <0.5% Routine follow-up or none
3 1-10% ~5% Short-term follow-up or MRI
4 10-50% ~50% Surgical consultation
5 >50% >90% GYN oncology referral

O-RADS US v2022

Classic Benign Lesions (Score 2)

  • Simple cyst: Anechoic, smooth walls, no solid component (any size premenopausal; ≤10cm postmenopausal)
  • Hemorrhagic cyst: Retractile clot, lace-like/fishnet strands
  • Dermoid: Echogenic lines/dots, fat-fluid level, Rokitansky nodule
  • Endometrioma: Homogeneous ground-glass echoes, no solid
  • Hydrosalpinx: Tubular, incomplete septa, cogwheel sign

Key US Features

  • Solid component: Strongest predictor of malignancy
  • Irregular inner wall: Papillary projections >3mm
  • Size ≥10cm: Upgrades multilocular without solid from 3 to 4
  • Ascites/peritoneal nodules: Automatic score 5

O-RADS MRI 2021

Solid Tissue Definition

Enhancing tissue with specific morphology:

  • Papillary projection: Branching from wall/septum
  • Mural nodule: >3mm nodular component
  • Irregular wall/septation: Uneven margins
  • Larger solid portion: Other enhancing solid tissue

NOT solid tissue: Smooth thin walls/septa, Rokitansky nodule, endosalpingeal folds, clot, debris

"Dark T2 / Dark DWI" Pattern

Homogeneous low signal on BOTH T2WI and high b-value DWI (entire lesion). Typical of fibroma, fibrothecoma, Brenner tumor. These are O-RADS MRI 2 regardless of enhancement.

Time Intensity Curve (TIC)

TIC Type Pattern O-RADS Score
Low-risk Gradual rise, no shoulder/plateau 3
Intermediate Shoulder + plateau, less steep than myometrium 4
High-risk Steep rise ≥ outer myometrium, then plateau/washout 5

References

  1. 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. doi:10.1148/radiol.2019191150
  2. Defined by ACR Committee. O-RADS US v2022: An Update. Radiology. 2023. doi:10.1148/radiol.230685
  3. Thomassin-Naggara I, Defined by ACR, et al. O-RADS MRI Risk Stratification System. Radiology. 2020;294(2):328-339. doi:10.1148/radiol.2019201694
  4. Defined by ACR Committee. O-RADS MRI Lexicon and Risk Stratification. Radiology. 2021. doi:10.1148/radiol.204371
  5. Defined by ACR Committee. O-RADS MRI Risk Stratification: Pearls and Pitfalls. Insights Imaging. 2024;15:49. doi:10.1186/s13244-023-01577-5
  6. American College of Radiology. O-RADS. ACR O-RADS