Selective angiography of the external carotid artery showing an indirect type D right<unk> , filling of the<unk>  sinus (arrow) and retrograde drainage into the right superior ophthalmic vein (arrowhead) This is based on MRI scan, magnetic resonance angiography and CT scan. A cerebral digital subtraction angiography (DSA) enhances visualization of the<unk> . * CT scans classically show an enlarged superior ophthalmic vein,<unk>  sinus enlargement ipsilateral (same side) as the abnormality and possibly diffuse enlargement of all the extraocular muscles resulting from venous engorgement. * Selective arteriography is used to evaluate arteriovenous<unk> s. * High resolution digital subtraction angiography may help in classifying<unk>  into dural and direct type and thus formulate a strategy to treat it either by a balloon or coil or both with or without preservation of parent ipsilateral carotid artery. Classification Various classifications have been proposed for<unk> . They may be divided into low-flow or high-flow, traumatic or spontaneous and direct or indirect. The traumatic<unk>  typically occurs after a basal skull fracture. The spontaneous dural<unk><unk>  which is more common usually results from a degenerative process in older patients with systemic hypertension and atherosclerosis. Direct<unk> s occur when the Internal Carotid artery (ICA) itself<unk> zes into the<unk>  sinus whereas indirect is when a branch of the ICA or External Carotid artery (ECA) communicates with the<unk>  sinus. A popular classification divides<unk>  into four varieties depending on the type of arterial supply. Type Description A<unk> us supply from the internal carotid artery B Supply from the dural branches of internal carotid artery C from meningeal branches of ext carotid artery D combined ICA+ECA
Carotid-cavernous fistula
Carotid artery dissection
Cirsoid aneurysm
Cavernous sinus thrombosis
Vertebral artery dissection
Vitreous hemorrhage
Carotid artery stenosis
Charcot–Bouchard aneurysm