Abstract #0955

Tammer R, Watanabe T, Boretius S, Frahm J, Michaelis T

Intracerebroventricular microinjection of potassium dichromate resulted in an enhancement of white matter tracts in T1-weighted MRI of mouse brain in vivo (2.35 T, 150 &[mu]m isotropic resolution). Pronounced signal increases were observed in corpus callosum, anterior commissure, and fornix as well as in the mammillothalamic tract and fasciculus retroflexus. The results suggest the diffusion of diamagnetic chromium(VI) to be followed by a reduction to paramagnetic chromium(III) due to the oxidation of myelin lipids and subsequent chromium retention. Without an enhancement of gray matter structures such as the hippocampal formation, chromium-induced contrast reveals novel information different from that obtainable using manganese.