Intracranial dural arteriovenous fistulas are abnormal connections between arteries and veins in dura-mater [1, 4] that occur mainly in women during the 5th- 6th decade [2, 4]. They account about 10% of all intracranial vascular malformations and localization is variable, being the posterior fossa the most frequent [1, 2, 4]. Symptomatology is determined by shunt localization [1, 2, 4] and vein drainage pattern . The most serious clinical presentation is hemorrhage, seizures or neurological deficits [1, 4].
Pathophysiology remains uncertain, but the most accepted theory in an acquired vein disorder [1, 3, 4]. Currently, the widest used scales are Cognard and Borden classifications [2, 4].
CT is the initial imaging test [1, 3 , 4]. It can depict dilated arteries, especially external carotid artery branches, accompanied by osseous resorption due to an enlargement of vascular foramina, and venous ectasia with surrounding edema and hydrocephalus [1, 2, 3]. Complicated cases can initiate with subdural, subarachnoid or most commonly intraparenchymal hemorrhage [1, 2, 4]. However, CT sensibility and specificity are limited [1, 3]. CT-Angiography rise sensibility up to 93%  and is important for treatment planning  but it can't evaluate precisely venous drain.
MRI is useful for screening and follow-up. T2 and SWI sequences show prominent and asymmetric vascular structures with hypointense signal inside the veins because of increased deoxyhemoglobin content while TOF images demonstrate arterial flow in venous vessels [1, 2, 3, 4]. Other imaging features are restricted diffusion and a better evaluation of parenchymal edema [3, 4]. Furthermore, gadolinium-enhanced time-resolve dynamic-
MRI increases sensibility and specificity up to 100% [3, 4]
Digital-subtraction angiography is the gold standard diagnosis technique due to its higher temporal, spatial and contrast resolution and allows endovascular therapy. [1, 2, 4]. Six-vessel angiography is recommended because shunt locations can be multiple and remote .
Treatment and follow up depend on natural history and patient preferences. Endovascular therapy is the first-line treatment if vessel anatomy is favourable. Procedure approach can be transarterial, transvenous or direct puncture [1, 2, 4].
Endovascular embolic agents include ethylene-vinyl-alcohol copolymer (Onyx). It's a nonadhesive embolic agent suspended in DMSO with tantalum for radioopacity. DMSO diffuses from the mixture on contact with blood causing polymer precipitation without vessel wall adhesion. This permits a more controlled injection, multiple pedicules and vein's origin treatment, and angiographic control during all the process. Therefore curative rates reach 80-100% [1, 4]
Open surgical treatment or radiosurgery are other treatments available [1, 2, 4].