Orbital inflammatory disease: Pictorial review and differential diagnosis

Figure 6 Indirect carotid-cavernous fistula. A: Coronal T2 MRI with fat saturation demonstrating mild infiltration of orbital fat (arrowhead) and thickening with high signal intensity in the EOMs. In this image, the lateral rectus muscle appears brightest (short white arrow). Note the enlarged SOV (long white arrow), suggesting CCF over myositis; B: Axial post-gadolinium T1 MRI with fat saturation. The SOV (long white arrow) is engorged secondary to retrograde flow from the cavernous sinus. The superior oblique muscle (short white arrow) is also enlarged; C: Angiogram with lateral projection common carotid artery injection (patient facing to the right) showing abnormal early filling in the cavernous sinus and SOV (short black arrows), as well as an abnormal tangle of vessels along dorsal surface of cavernous sinus (long black arrow), representing abnormally dilated intracavernous ICA branches. MRI: Magnetic resonance imaging; EOM: Extraocular muscles; SOV: Superior ophthalmic vein; CCF: Carotid cavernous fistula; ICA: Internal carotid artery.