Restricted diffusion in the superior ophthalmic vein and cavernous sinus in a case of cavernous sinus thrombosis

A previously healthy 14-year-old boy developed headache, stiff neck, fever, diplopia, right proptosis, and right complete sixth and partial third cranial nerve palsies. Orbital CT showed features of pansinusitis and orbital fat stranding. An initial diagnosis of orbital cellulitis was made. However, closer inspection of the CT disclosed nonfilling of the right superior ophthalmic vein (SOV) and both cavernous sinuses, suggesting cavernous sinus thrombosis (CST). CT venography (CTV) confirmed these features and disclosed nonobstructing thrombus within the left sigmoid sinus and proximal segments of both internal jugular veins. MRI with diffusion imaging disclosed evidence of restricted diffusion within the SOV and cavernous sinuses. These diffusion imaging findings, which may be analogous to those reported with brain parenchymal hematoma, have been described sparingly in intravascular hematoma.