Imagerie des affections dégénératives de l'encéphale

Neurodegenerative disorders are a group of diseases which all induce a progressive dysfunction of the central nervous system. Until recently, neuro imaging played only a marginal part in their diagnosis, and was mostly useful for the follow-up of some disorders. However, in the last score years, the ability of MRI to differentiate normal from pathological brain ageing has steadily improved. Three dimensional acquisitions and multi planar reconstructions enable precise volumetric measurements of individual brain regions. They are used to classify dementias and focal degenerative brain disorders. More recently, functional MRI methods (such as functional MRI, diffusion imaging and diffusion tensor imaging) and metabolic analyses (such as PET, SPECT and MR spectroscopy) provide insights on the physiopathology of these diseases. These methods are still mostly used in research settings but will progressively play an increasing part in the clinical management of these patients.