Visualizing manganese in the primate basal ganglia with magnetic resonance imaging

Abstract

The paramagnetism of manganese was exploited to obtain proton nuclear magnetic resonance (MR) images of manganese-rich tissue in the central nervous system in vivo. One Macaca fascicularis monkey inhaled MnCl2 aerosol prior to imaging. A second M. fascicularis and two Cebus apellas were administered MnCl2 in various doses intravenously. The monkeys' brains were imaged before and after manganese administration in coronal and horizontal planes that included the basal ganglia and substantia nigra. A T1-weighted pulse sequence exploited manganese's reduction of spin-lattice relaxation times and clearly distinguished several separate and specific regions after manganese administration: the caudate nucleus, the lenticular nuclei, the substantia nigra, a region corresponding to subthalamic nucleus and ventromedial hypothalamus, and the pituitary gland. The kinetics of manganese accumulation were important in determining the imaged intensity of these regions but the route of parenteral administration was not. Spin-lattice relaxation times showed that T1 was shortened at lower doses of manganese and remained shortened longer in the globus pallidus and pituitary gland while little effect appeared in gray and white matter. T1 effects in caudate and putamen effects were intermediate. These data suggest selective affinity for manganese in globus pallidus and pituitary.