RadEssentialReading-room reference
C-RADS (CT colonography)
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Colonic findings get a C category and extracolonic findings an E category; report both. Polyps are measured by the largest diameter of the head, excluding any stalk, on 2D or 3D views. Polyps under 6 mm are not reported.
Colonic findings
| Category | Findings | Management |
|---|---|---|
| C0 | Inadequate prep or insufflation (cannot exclude a ≥10 mm lesion), or awaiting prior studies | Complete or repeat |
| C1 | Normal colon or benign lesion; no polyp ≥6 mm. Lipoma, inverted diverticulum, diverticulosis | Routine screening, 5–10 yr |
| C2 | Intermediate polyp 6–9 mm, fewer than 3; or indeterminate finding (cannot exclude ≥6 mm polyp) | Surveillance or colonoscopy |
| C3 | Polyp ≥10 mm, or 3 or more polyps each 6–9 mm (possibly advanced adenoma) | Colonoscopy |
| C4 | Colonic mass, likely malignant: compromises the lumen or shows extracolonic invasion | Surgical consultation |
Extracolonic findings
| Category | Meaning | Examples |
|---|---|---|
| E0 | Limited exam: artifact severely limits soft tissues | — |
| E1 | Normal exam or anatomic variant | Retroaortic left renal vein |
| E2 | Clinically unimportant; no work-up | Simple liver or renal cyst, cholelithiasis without cholecystitis, vertebral hemangioma |
| E3 | Likely unimportant, incompletely characterized; work-up per local practice and patient preference | Minimally complex or homogeneously hyperattenuating renal cyst |
| E4 | Potentially important; communicate to the referring physician | Solid renal mass, lymphadenopathy, aortic aneurysm, non-uniformly calcified lung nodule ≥1 cm |
C2 surveillance: evidence supports delaying CTC follow-up at least 3 years, subject to the individual patient. Report polyp morphology (sessile, pedunculated, flat) and segment location.
Sources
- Zalis ME, Barish MA, Choi JR, et al. CT colonography reporting and data system: a consensus proposal. Radiology. 2005;236:3–9.PubMed ↗
Radessential summarizes published classification systems for practicing radiologists. Summaries are condensed; confirm details against the cited source before relying on them for patient care.