Classification nomenclature for dural arteriovenous fistulas
| Classification | Description |
| Borden | |
| Type I | Venous drainage directly into dural sinus or meningeal veins |
| Type II | Venous drainage into dural sinus with CVR |
| Type III | Venous drainage directly into cortical veins only |
| Cognard | |
| Type I | Normal antegrade venous drainage into dural sinus |
| Type IIa | Retrograde venous drainage into dural sinus |
| Type IIb | Retrograde venous drainage into cortical veins (CVR) |
| Type IIa + b | Retrograde venous drainage into dural sinus with CVR |
| Type III | Direct venous drainage into cortical veins without venous ectasia |
| Type IV | Direct venous drainage into cortical veins with venous ectasia >5 mm |
| Type V | Direct venous drainage into spinal perimedullary plexus |
CVR, cortical venous reflux.