Acute vasogenic edema induced by thrombosis of a giant intracranial aneurysm: a cause of pseudostroke after therapeutic occlusion of the parent vessel.

A 16-year-old male adolescent presenting with acute retro-orbital pain underwent emergent internal carotid occlusion for a giant cavernous aneurysm. Three weeks later, the patient complained of headache and right hemiparesis, which suggested an acute stroke. CT and MR imaging revealed vasogenic brain edema without infarct. The symptoms rapidly resolved with steroid therapy. Follow-up CT showed resolution of the edema. The imaging characteristics, clinical implications, and etiology of vasogenic edema occurring after thrombosis of a giant intracranial aneurysm are discussed.