**5. Diagnosis**

Catheter angiography is the gold standard technique for the diagnosis and classification of DAVFs. Based on the site of DAVF, this method is usually performed by using the four-vessel technique injections with an injection into the external carotid arteries. Several dural arterial feeders with early drainage into a dural sinus or cortical vein are mostly revealed on angiograms. Also, conventional angiograms are used to classify DAVFs based on the venous architecture and the extent of cortical venous reflux.

Among all the used methods for the diagnosis of DAVFs like CT, CT angiography, MRI and MR angiography, CT has been the initial neuroimaging method. Although it can reveal areas of ischemia, edema and ICH, it could not identify DAVF ideally. On the other hand, CTA has been a better method for identifying DAVFs, because it can show a dilated vessel associated with an ICH or calcification with chronically congested veins. Also, MRA has the same ability of CTA of showing dilated vessels.

As both MRA and CTA can show the site of DAVFs in relation to normal brain structures, they are both used as adjuvant methods to catheter angiography, which allows both techniques to be used in intraoperative navigation [14, 15].

*Arteriovenous Fistulas: The Pathological Bridge DOI: http://dx.doi.org/10.5772/intechopen.89724*

## **6. Rare cases**

## **6.1 Case 1**

This is the first case of a DAVF causing isolated intraventricular hemorrhage with radiographic evidence of several cortical venous refluxes into the subependymal venous network. Also, it is the first case of DAVF that was successfully cured using multimodality transvenous and trans-arterial embolization techniques. A hypertensive, diabetic 84-year-old woman whose modified Rankin scale score is 0, presented to the emergency room complaining of headache for 4 days, nausea, vomiting and worsening confusion with episodes of severe drowsiness. Noncontrast CT scan of the head, CT angiogram of the brain, and digital subtraction cerebral angiogram were performed. She was treated by transvenous coil embolization of the right transverse/sigmoid sinus using POD5 and penumbra −400 coils and trans-arterial onyx-18 embolization of the right middle meningeal artery. She had 4- and 6-week follow-up by diagnostic angiogram and 6-week follow-up by clinical examination. The angiogram 6-week follow-up revealed that the DAVF went through complete resolution; the clinical 6-week follow-up showed that the patient mental status returned to normal and her headache resolved [18].
