The Cognard classification is used alongside the Borden classification to classify dural arteriovenous fistulas. Using the Cognard classification, dural arteriovenous fistulas are divided into 5 different types[^1].
Classification
Cognard type | Description |
Type I | Normal anterograde flow in dural sinuses |
Type IIa | Retrograde flow in the sinuses |
Type IIb | Retrograde filling of cortical veins |
Type IIc | Retrograde drainage into the sinuses and cortical veins |
Type III | Direct drainage into cortical veins with retrograde flow |
Type IV | Direct drainage into cortical veins with venous ectasia > 5 mm and 3 times larger than the draining vein |
Type V | Drainage into spinal perimedullary veins |