🧫 CT Colonography C-RADS Classification
Get the colonic (C0–C4) and extracolonic (E0–E4) categories and management for CT colonography per C-RADS v2023. Instant, browser-side.
Clinical takeaway
Category set by the highest-grade lesion.
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When to use
Classify a CT colonography study and set the management for both colonic and extracolonic findings.
How it works
C1 normal → routine screening (5–10 yr); C2 (1–2 polyps 6–9 mm) → CTC surveillance ~3 yr or colonoscopy; C3 (≥ 10 mm or ≥ 3 polyps 6–9 mm) → colonoscopy; C4 suspected malignant → surgical/oncology referral.
Key points
- Category set by the highest-grade lesion.
- v2023 adds C2b (diverticular mass-like stricture) and merges E1/E2.
- Extracolonic E1/E2 need no follow-up; E3 work-up as indicated; E4 further management.
- E0 extracolonic reporting is optional in v2023.
References
Decision support for licensed clinicians only; not a substitute for clinical judgement, diagnosis or local protocols.
Worked calculation
The values below come from this tool's own example placeholders and are computed server-side with the formula shown on this page, so the arithmetic can be checked quickly. It demonstrates how to substitute values only — it is not clinical advice and not a real case.
| Colonic category (C) | C0 — Inadequate / non-diagnostic |
|---|---|
| Extracolonic category (E, optional) | Not assessed / not selected |
→Colonic managementRepeat / supplement
- Colon C0：Inadequate / non-diagnostic (poor prep or distension, or awaiting prior comparison); management: Repeat or supplement, then re-classify
- Note：C-RADS v2023: colonic C0–C4 (adds C2b diverticular mass-like stricture), extracolonic E0–E4 (E1/E2 merged, E0 reporting optional); category set by the highest-grade lesion
- Basis：C-RADS CT Colonography Reporting and Data System v2023
| Colonic category (C) | C4 — Suspected malignant mass |
|---|---|
| Extracolonic category (E, optional) | E4 — Potentially important |
→Colonic managementSurgical/oncology referral
- Colon C4：Suspected malignant mass (luminal narrowing/invasion); management: Surgical/oncology multidisciplinary referral
- Extracolonic E4：Potentially clinically important; management: Communicate and pursue further work-up/management
- Note：C-RADS v2023: colonic C0–C4 (adds C2b diverticular mass-like stricture), extracolonic E0–E4 (E1/E2 merged, E0 reporting optional); category set by the highest-grade lesion
Frequently asked questions
- What is CT Colonography C-RADS Classification?
- Get the colonic (C0–C4) and extracolonic (E0–E4) categories and management for CT colonography per C-RADS v2023. Instant, browser-side.
- How is CT Colonography C-RADS Classification calculated? What is the core formula?
- C1 normal → routine screening (5–10 yr); C2 (1–2 polyps 6–9 mm) → CTC surveillance ~3 yr or colonoscopy; C3 (≥ 10 mm or ≥ 3 polyps 6–9 mm) → colonoscopy; C4 suspected malignant → surgical/oncology referral.
- When is CT Colonography C-RADS Classification used?
- Classify a CT colonography study and set the management for both colonic and extracolonic findings.
- What are the key clinical points for CT Colonography C-RADS Classification?
- Category set by the highest-grade lesion. v2023 adds C2b (diverticular mass-like stricture) and merges E1/E2. Extracolonic E1/E2 need no follow-up; E3 work-up as indicated; E4 further management. E0 extracolonic reporting is optional in v2023.
- What are the limits and cautions when using CT Colonography C-RADS Classification?
- For licensed clinicians and clinical researchers. Interpret results with history, investigations and local protocols; not a diagnosis or prescription, and not a substitute for multidisciplinary decision-making or local guidelines.
- How is CT Colonography C-RADS Classification calculated in practice? Can you show a worked example?
- Inputs: Colonic category (C) C0 — Inadequate / non-diagnostic, Extracolonic category (E, optional) Not assessed / not selected → Result: Colonic management Repeat / supplement（Colon C0: Inadequate / non-diagnostic (poor prep or distension, or awaiting prior comparison); management: Repeat or supplement, then re-classify, Note: C-RADS v2023: colonic C0–C4 (adds C2b diverticular mass-like stricture), extracolonic E0–E4 (E1/E2 merged, E0 reporting optional); category set by the highest-grade lesion, Basis: C-RADS CT Colonography Reporting and Data System v2023） Inputs: Colonic category (C) C4 — Suspected malignant mass, Extracolonic category (E, optional) E4 — Potentially important → Result: Colonic management Surgical/oncology referral（Colon C4: Suspected malignant mass (luminal narrowing/invasion); management: Surgical/oncology multidisciplinary referral, Extracolonic E4: Potentially clinically important; management: Communicate and pursue further work-up/management, Note: C-RADS v2023: colonic C0–C4 (adds C2b diverticular mass-like stricture), extracolonic E0–E4 (E1/E2 merged, E0 reporting optional); category set by the highest-grade lesion）