Interactive O-RADS Ultrasound Calculator
Use this tool to estimate an O-RADS US category (0–5) for adnexal lesions based on key ultrasound features. This is an educational aid and not a clinical diagnosis.
What is an O-RADS calculator?
The O-RADS Ultrasound system (Ovarian-Adnexal Reporting and Data System) is a standardized way to describe and risk-stratify ovarian and adnexal findings seen on ultrasound. Instead of vague wording like “complex cyst, follow clinically,” O-RADS provides a clearer framework that helps clinicians communicate risk and choose follow-up.
This calculator translates common ultrasound features into an estimated category from O-RADS 0 to O-RADS 5. It is helpful for learning and structured documentation, especially when comparing cases over time.
How this calculator estimates risk
The calculator uses key factors that strongly influence risk level:
- Exam completeness: Incomplete scans are classified as O-RADS 0.
- Lesion morphology: Simple, classic benign, unilocular, multilocular, or solid patterns.
- Size: Larger lesions may move into higher categories.
- Papillary projections: More projections generally imply greater concern.
- Doppler vascularity (color score): Stronger flow can indicate higher risk.
- Ascites/peritoneal nodules: These findings can upgrade to high-risk categories.
O-RADS category quick guide
O-RADS 0: Incomplete
Study is technically limited or incomplete. Repeat or additional imaging is usually needed.
O-RADS 1: Normal physiologic finding
Essentially normal ovarian/adnexal imaging appearance.
O-RADS 2: Almost certainly benign (<1%)
Typical examples include small simple cysts and classic benign lesions below key size thresholds.
O-RADS 3: Low risk (1% to <10%)
Usually lesions with low-level concerning features, often managed with follow-up imaging or specialist review depending on context.
O-RADS 4: Intermediate risk (10% to <50%)
More complex morphology or concerning vascularity. Often merits stronger workup (specialist review, possible MRI, and individualized planning).
O-RADS 5: High risk (≥50%)
Findings are highly suspicious for malignancy and typically require prompt referral to gynecologic oncology pathways.
Practical interpretation tips
- Use O-RADS as a structured communication tool, not a standalone diagnosis.
- Symptoms, age, tumor markers, MRI findings, and family history still matter.
- Postmenopausal patients often have a lower tolerance for indeterminate findings.
- When in doubt, compare with prior imaging and document interval change clearly.
Example use cases
Example 1: 4 cm simple cyst
Simple morphology, no ascites, low Doppler flow, small size: often falls in O-RADS 2.
Example 2: 12 cm multilocular smooth cyst
Larger size and complexity generally push risk upward, commonly O-RADS 4 depending on flow and other features.
Example 3: Irregular solid lesion with strong Doppler flow
Irregular solid architecture plus strong vascularity is highly suspicious and frequently classified as O-RADS 5.
Important limitations
This web calculator is a simplified educational model aligned with core O-RADS principles. It does not replace full ACR O-RADS documentation, institutional protocols, or physician judgment. Clinical decisions should be made by qualified professionals using complete imaging and patient context.
Final thoughts
A good O-RADS workflow improves consistency, reduces ambiguity in reports, and helps align radiology with gynecology and oncology teams. If you are learning adnexal mass risk stratification, this calculator is a practical starting point for understanding how morphology and vascularity influence category assignment.