Cerebral angiography is the diagnostic standard. MRIs are typically normal but can identify venous hypertension as a result of arterial-venous shunting. Classification Borden Classification The Borden Classification of dural<unk>  malformations or<unk> s, groups into three types based upon their venous drainage: # Type I: dural arterial supply drains anterograde into venous sinus. # Type II: dural arterial supply drains into venous sinus. High pressure in sinus results in both anterograde drainage and retrograde drainage via subarachnoid veins. # Type III: dural arterial supply drains retrograde into subarachnoid veins. Type I Type I<unk> s are supplied by meningeal arteries and drain into a meningeal vein or dural venous sinus. The flow within the draining vein or venous sinus is anterograde. # Type Ia – simple<unk> s have a single meningeal arterial supply # Type Ib – more complex<unk><unk> s are supplied by multiple meningeal arteries The distinction between Types Ia and Ib is somewhat specious as there is a rich system of meningeal arterial collaterals. Type I dural<unk> s are often asymptomatic, do not have a high risk of bleeding and do not necessarily need to be treated. Type II The high pressure within a Type II dural AV<unk>  causes blood to flow in a retrograde fashion into subarachnoid veins which normally drain into the sinus. Typically this is because the sinus has outflow obstruction. Such draining veins form venous varices or aneurysms which can bleed. Type II<unk> s need to be treated to prevent hemorrhage. The treatment may involve embolization of the draining sinus as well as clipping or embolization of the draining veins. Type III Type III dural AV<unk> s drain directly into subarachnoid veins. These veins can form aneurysms and bleed. Type III dural<unk> s need to be treated to prevent hemorrhage. Treatment can be as simple as clipping the draining vein at the site of the dural sinus. If treatment involves embolization, it will only typically be effective if the glue traverses the actual<unk>  and enters, at least slightly, the draining vein. The Cognard et al. Classification correlates venous drainage patterns with increasingly aggressive neurological clinical course. Classification Location and clinical course Type I Confined to sinus wall, typically after thrombosis. Type II IIa - confined to sinus with reflux (retrograde) into sinus but not cortical veins. IIb - drains into sinus with reflux (retrograde) into cortical veins (10-20% hemorrhage). Type III Drains direct into cortical veins (not into sinus) drainage (40% hemorrhage). Type IV Drains direct into cortical veins (not into sinus) drainage with venous ectasia (65% hemorrhage). Type V Spinal perimedullary venous drainage, associated with progressive myelopathy. To simplify the above systems of<unk>  classification, the two main factors that should be considered to determine aggressiveness of these lesions are: *<unk>  that have bleed (as opposed to those that have not before) *<unk>  resulting in cortical venous reflux Treatment decisions are more complicated and require consultation with a neurosurgeon and team familiar with these lesions.
Dural arteriovenous fistula
Arteriovenous fistula
Pseudoaneurysm
Developmental venous anomaly
Dural ectasia
Cavernous venous malformation
Subungual hematoma
Angiofibroma of soft tissue