Cognard Classification (Dural AV Fistula)
Derives the Cognard type (I to V) of an intracranial dural arteriovenous fistula from its venous drainage on angiography.
Open the calculator → Runs in your browser. Data leaves only if you deliberately send a problem report from the interactive tool.
Example
- Venous drainage
- Into a dural sinus
- If into a sinus: retrograde flow within the sinus
- Yes
- If into a sinus: reflux into cortical veins
- Yes
Result: Cognard type IIa+b: drainage into a sinus with reflux into the sinus and cortical veins. Cortical venous drainage is present, the aggressive group (about 8% annual hemorrhage in the source review).
The tool opens with these values already filled in. Replace them with your own.
What you enter
- Venous drainage
- If into a sinus: retrograde flow within the sinus
- If into a sinus: reflux into cortical veins
- If direct cortical: venous ectasia
How this is calculated
Citation
Cognard C, Gobin YP, Pierot L, et al. Cerebral dural arteriovenous fistulas: clinical and angiographic correlation with a revised classification of venous drainage. Radiology. 1995;194(3):671-680. Read the sources: Cognard 1995 ↗, Sim 2022 (types and risk) ↗
A reference and educational tool. Not medical, legal, or financial advice, and not a substitute for clinician judgment.