RadEssentialReading-room reference
Dural AV fistula: Cognard & Borden
Both systems are driven by venous drainage pattern. Cortical venous reflux (CVR) is the key feature that predicts hemorrhage and venous infarction.
Cognard
| Type | Venous drainage | Risk |
|---|---|---|
| I | Into sinus, antegrade flow | Benign |
| IIa | Into sinus, retrograde flow within sinus(es) | Low |
| IIb | Into sinus, antegrade, with reflux into cortical veins | Aggressive |
| IIa+b | Retrograde sinus flow and cortical venous reflux | Aggressive |
| III | Direct cortical venous drainage, no venous ectasia | Aggressive |
| IV | Direct cortical venous drainage with venous ectasia (>5 mm and >3× diameter of draining vein) | Aggressive |
| V | Drainage into spinal perimedullary veins | Myelopathy |
Borden
| Type | Venous drainage |
|---|---|
| I | Into dural sinus or meningeal vein, normal antegrade flow |
| II | Into dural sinus with cortical venous reflux |
| III | Directly into cortical veins (no sinus) |
On CTA/MRI, suspect CVR when there are dilated tortuous cortical veins without a parenchymal nidus, or venous congestion/edema. DSA remains the reference standard for classification.
Sources
- 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;194:671–680.PubMed ↗
- Borden JA, Wu JK, Shucart WA. A proposed classification for spinal and cranial dural arteriovenous fistulous malformations and implications for treatment. J Neurosurg. 1995;82:166–179.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.