Incidentally Detected Cerebral Ischemia with Contralateral Muscular “Hemi-hypometabolism” on FDG PET in a Patient with Incidentally Discovered Internal Carotid Artery Occlusion

A 44-year-old man underwent fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) positron emission tomography/computed tomography (PET/CT) for evaluation of possible multiple myeloma and was found to have significant asymmetry in cerebral and muscular FDG uptake. Imaging demonstrated right cerebral hemisphere hypometabolism with crossed cerebellar diaschisis and asymmetric muscle uptake suggestive of chronic cerebral ischemia. Further evaluation with CT angiography identified right internal carotid artery occlusion. This case highlights unique FDG PET/CT features of chronic cerebral ischemia, including cerebral metabolic dysfunction, diaschisis, and asymmetric muscular uptake.