We report a case of a 46-year-old man who underwent a hybrid PET-MRI study 3 months after an acute ischemic stroke of the left middle cerebral artery territory. The FDG PET images show a severe hypometabolism occurring in the cortical and subcortical ischemic territory, as well as in functionally connected but intact areas, such as the homolateral pons and the contralateral cerebellar hemisphere. The MRI images show T2 hyperintensity in the pyramidal and frontopontine tract, associated with fiber degeneration, and no significant cerebellar atrophy. Hybrid PET-MRI imaging can measure various correlates (fiber degeneration and metabolic disconnection) of the diaschisis phenomenon.