O-RADS Ultrasound · Adnexal Mass Risk Stratification

Step-by-step decision

Choose step by step as prompted; reaching an endpoint gives the management recommendation. You can go back a step or restart anytime.

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Full pathway

1. [Decision] Primary determination
   Primary determination: adequate technique / physiologic / needs morphology scoring? (O-RADS US v2022 is for the ovary, adnexa/tube, and paraovarian cyst (assessing malignancy risk). Not applicable: PID, ectopic pregnancy, normal ovary, torsion, clearly non-ovarian source (e.g. fibroid). Color score CS: 1 no flow/2 minimal/3 moderate/4 marked. First distinguish physiologic and classic benign lesions (CBL), score the rest by morphology.)
   • Technically inadequate/ovary not adequately seen → O-RADS 0 · technically inadequate
   • Premenopausal physiologic (follicle ≤3 cm/corpus luteum ≤3 cm) → O-RADS 1 · normal physiologic
   • Lesion needs morphology scoring (cystic/solid) → Morphology stratification
2. [End] O-RADS 0 · technically inadequate
   O-RADS 0 (incomplete evaluation/technically inadequate): optimize the exam (transvaginal + transabdominal, fill/timing adjustment, repeat later), MRI or expert ultrasound re-review then re-stratify if needed.
3. [End] O-RADS 1 · normal physiologic
   O-RADS 1 (premenopausal normal physiologic: follicle ≤3 cm/corpus luteum ≤3 cm): normal finding, no management or follow-up needed.
4. [Decision] Morphology stratification
   Morphology stratification: size / locularity / solid component / color score / typical benign features? (Unilocular = no complete septation; bilocular = one smooth complete septation; multilocular = ≥2 septations (v2022 distinguishes bilocular from multilocular). Classic benign lesions (CBL): hemorrhagic cyst, endometrioma, dermoid cyst (teratoma). Irregular inner wall/septation (focal thickening <3 mm, not a true solid component) raises the score.)
   • Uni/bilocular smooth <10 cm, or CBL <10 cm → O-RADS 2 · almost certainly benign (<1%)
   • Uni/bilocular smooth ≥10 cm or CBL ≥10 cm, or multilocular <10 cm smooth CS1–3, or smooth solid CS1 → O-RADS 3 · low risk (1–<10%)
   • Multilocular ≥10 cm or CS4, or solid component within cyst CS1–3, or smooth solid CS2–3 → O-RADS 4 · intermediate risk (10–<50%)
   • Irregular solid, or multilocular + solid component CS4, or ascites/peritoneal nodules → O-RADS 5 · high risk (≥50%)
5. [End] O-RADS 2 · almost certainly benign (<1%)
   O-RADS 2 (almost certainly benign, malignancy risk <1%): conservative management; follow-up by lesion type and size (some simple cysts/small CBL need no follow-up).
6. [End] O-RADS 3 · low risk (1–<10%)
   O-RADS 3 (low risk, 1–<10%): v2022 permits short-term ultrasound follow-up; solid O-RADS 3 is still better characterized with MRI; ultrasound expert/gynecology assessment if needed.
7. [End] O-RADS 4 · intermediate risk (10–<50%)
   O-RADS 4 (intermediate risk, 10–<50%): MRI for further characterization (O-RADS MRI) or gynecology/gynecologic oncology consult; integrate with CA125, etc.
8. [End] O-RADS 5 · high risk (≥50%)
   O-RADS 5 (high risk, ≥50%; irregular solid, multilocular + solid + high color score, ascites/peritoneal nodules): gynecologic oncology consult ± surgery; complete staging imaging and CA125.

Source guidelines & references

• ACR O-RADS US v2022 risk stratification and management (Radiology 2023)
• O-RADS US consensus (Radiology 2020) · source ↗

This pathway is our own synthesis of the decision logic in the guidelines above (not the guideline verbatim); thresholds and workflows change as guidelines update — in practice follow the latest guideline, your institution's protocol and the individual patient.

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