Contrast-Enhanced Magnetization Transfer MRI at 9.4 T: Myelin Mapping in the Central Nervous System of Living Mice

Takashi Watanabe¹, Jens Frahm¹, Thomas Michaelis¹

This work demonstrates the use of MnCl₂ and Gd-DTPA to improve the white/gray matter contrast in magnetization-transfer MRI (3D FLASH) of the brain and spinal cord of living mice at 9.4 T. A systemic Mn²⁺ administration followed by an intraventricular Gd-DTPA administration increased the white/gray matter CNR by 136%. At 60 μm isotropic resolution, myelinated fibers and layers were delineated with the contrast agents, even within the gray matter. The contrast enhancement can be explained by its lower/higher concentration of the contrast agents in the white/gray matter, with the extracellular space in the white/gray matter estimated to be 15%/27%, respectively.