SIGNAL CHANGES ON MRI AND INCREASES IN REACTIVE MICROGLIOSIS, ASTROGLIOSIS, AND IRON IN THE PUTAMEN OF 2 PATIENTS WITH MULTIPLE SYSTEM ATROPHY

A correlation of clinical, MRI, and neuropathological data is reported in two patients with multiple system atrophy (MSA). On MRI, patient 1 showed striatal atrophy, reduction of T2 relaxation times within most of the putamen, and a band of hyperintense signal changes in the late ral putamen. In patient 2, MRI disclosed only shortening of the T2 sig nal in the putamen. Immunohistochemistry showed pronounced reactive mi crogliosis and astrogliosis in the affected brain regions. In patient 1, the area with the most pronounced microgliosis and astrogliosis mos t likely correlated with the area of hyperintense signal changes on MR I. This area also contained the highest amount of ferric iron, which w as increased in the putamen of patient 1 but not patient 2. It is unli kely that the hypointense signal changes in the putamen are due to an increase of iron alone. Reactive microglial and astroglial cells may p lay a part in the pathogenesis of MSA.