A comparison study of SPECT and MRI was performed to investigate remote effects in 10 patients with chronic cerebrovascular disease. Hypoperfusion in the cerebellar hemisphere contralateral to supratentorial lesions, the overlying cerebral cortex ipsilateral to subcortical lesions, the thalamus ipsilateral to cortical lesions, and the visual cortex distant to optic radiation lesions was demonstrated using SPECT with 123I-IMP. Although hypoperfusion in these remote areas was considered to be related to irreversible degenerative processes in the chronic phase, MR images did not reveal any abnormalities.