[Perfusion brain SPECT and Alzheimer disease].

Alzheimer Disease (AD) is the most frequent cause of degenerative dementia. There is an asymptomatic phase of the disease. Brain single photon computed tomography (SPECT) is a simple way to investigate the cerebral blood flow. Alzheimer's disease is characterized by hypoperfusion in the medial temporal, associative posterior parietal cortex and frontal cortex. Brain SPECT could also have an interest in the early detection of amnesic mild cognitive impairment (MCI) patients with a high risk of conversion to AD. Indeed, the hypoperfusion of the associative parietal cortex in MCI patients is considered predictive of a rapid conversion to AD. Different scintigraphic patterns of neurodegenerative dementias could be used for their differential diagnosis.