MR imaging in Fahr disease.

The calcifications of Fahr disease that are detected by CT in the dentate nuclei of the cerebellum, basal ganglia, and white matter of the cerebral hemispheres displayed three patterns with magnetic resonance imaging using the multiple echo technique: (a) cerebellar calcifications were undetected; (b) basal ganglia calcifications displayed low or no signal and appeared as "black" areas in four echoes; and (c) white matter calcifications displayed a high signal in the four echoes and appeared intensely white. The different behavior of the three calcified sites probably reflects different stages of the disease or different metabolic states with predominance of inert calcium deposits in the basal ganglia. In the white matter there is probably a higher concentration of binding proteins and mucopolysaccharides.