Figure 12.

Right orbital AVM in a 14-year-old girl with progressive proptosis, strabismus and visual loss. A red pulsatile mass in the upper lid was already evident at clinical examination (A); a thrill was also perceptible at palpation. Coronal T2 TSE sequence (B) shows a massive trans-spatial expansile lesion occupying the entire orbit, distorting its anatomy; signal intensity is highly inhomogeneous due to the presence of tortuous flow-voids (black arrow in B) and blood products of varying age (white arrow in B). The other MR sequences did not demonstrate any intracranial extension of the vascular malformation (not shown). The arterial phase of the DSA (lateral view, C) depicts the dilated and slightly tortuous right ophthalmic artery (grey arrowhead, arising from the supraclinoid segment of the internal carotid artery) feeding the orbital AVM, the nidus (white asterisk) and the early opacification of the draining vein, the superior ophthalmic vein (white arrowhead). The venous drainage is better seen in the venous phase of the DSA (lateral view, D), occurring mainly through the dilated right superior ophthalmic vein (white arrowhead), which drains into the cavernous sinus.