C-RADS™ v. 2023

ACR's CT Colonography Imaging Reporting & Data System, for describing colorectal and extra-colonic findings - Version 2023 (released January 2024)

C-RADS

Extra-colonic findings

Which of the following applies to the current exam?

Examination inadequate for assessment

No clinically important extracolonic findings

Stable previously known extracolonic findings that require no additional workup

Likely clinically unimportant finding

Likely clinically important finding

E0

Incidence rate of 3%

E1/E2

Incidence rate of 86-88%

No additional workup is indicated

E3

Incidence rate of 4-16%

Further workup may be warranted

E4

Incidence rate of 2-8%

Further workup needed

The scoring of extracolonic findings per C-RADS is very straightforward. Please refer to the following table:

E0 = Limited exam	Compromised by artifact; evaluation of extracolonic soft tissues is severely limited.	No recommendations.
E1 = Normal exam or anatomic variant	No extracolonic abnormalities visible. Anatomic Variant: eg, retroaortic left renal vein	No recommendations.
E2 = Clinically unimportant finding	Examples: a. Liver, Kidney: simple cysts b. Gallbladder: cholelithiasis without cholecystitis c. Vertebra: hemangioma	No work-up indicated.
E3 = Likely unimportant finding or incompletely characterized	Examples: a. Kidney: minimally complex or homogeneously hyperattenuating cyst	Subject to local practice and patient preference, work-up may be indicated.
E4 = Potentially important finding	Examples: a. Kidney: solid renal mass b. Lymphadenopathy c. Vasculature: aortic aneurysm d. Lung: non-uniformly calcified parenchymal nodule ≥1 cm	Communicate to referring physician as per accepted practice guidelines.

Click here to visit C-RADS page on ACR.

C-RADS™ v. 2023

Colonic findings

C0 = Inadequate Study

Repeat CTC or consider an alternative screening test if inadequate.

C0 = Awaiting prior comparisons

Amend when prior studies are available.

C1 = Normal Colon or Benign Lesion

Recommendation: Continue routine screening every 5-10 years

C2a = Intermediate Polyp or Indeterminate Finding

Recommendation: Repeat CTC in 3y or colonoscopy. For polyps 6 mm and greater, recommend polypectomy in suitable patients versus follow-up study in 3 years, subject to individual patient circumstance.

C2b = Likely benign diverticular finding

Likely benign: recommend repeat CTC in 5 y

Uncertain benign: recommend repeat CTC in ≤3 y

C3 = Polyp, Possibly Advanced Adenoma

Recommendation: Colonoscopy

Communicate to referring physician as per accepted guidelines for communication, such as American College of Radiology Practice Parameter for Communication of Diagnostic Imaging Findings. Subject to local practice, endoscopic biopsy may be indicated.

C4 = Likely Malignant Colonic Mass

Recommendation: Surgical and/or oncologic consultation.