Contrast-induced Encephalopathy after Coil Embolization of an Unruptured Internal Carotid Artery Aneurysm

A 58-year-old woman developed agraphia and mild right hemiparesis approximately one month after undergoing coil embolization of an unruptured left internal carotid artery aneurysm. MRI performed on day 39 post-coil embolization showed multiple lesions in the white matter with signal hyperintensity on T2-weighted and FLAIR images in the left middle cerebral artery territory. The patient's cerebrospinal fluid exhibited an elevated protein level at 46 mg/dL; however, no other findings suggested another underlying disease. Corticosteroids were administered, and, by day 50 post-coil embolization, the clinical findings and abnormal features on MRI had improved. The patient was therefore diagnosed with contrast-induced encephalopathy after coil embolization.