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Free keywords:
dorsal motor nucleus of vagus; gadolinium-based contrast agent; locus coeruleus; macrocyclic; magnetization transfer; nucleus ambiguus
Abstract:
Three-dimensional T1-weighted MRI of mouse brain in vivo (9.4 T, 80 µm isotropic resolution) identified assemblies of nerve cell bodies in the habenula, hippocampal formation, locus coeruleus, dorsal motor nucleus of vagus, and nucleus ambiguus as high signal intensities, while suppressing the signals of white matter by magnetization transfer and extracellular water protons by saturation. These observations indicate the presence of intracellular water protons with T1 values shortened by paramagnetic ions as the source of the bright signal. One day after an intraventricular injection of gadobutrol, a macrocyclic gadolinium-based contrast agent, T1-weighted MRI signal intensities of the nerve cell assemblies in the habenula, hippocampal formation, and locus coeruleus increased significantly. With simultaneous saturation of long-T1 protons of extracellular water, this finding indicates a T1-shortening of the intracellular water protons as a result of their interaction with gadolinium ions.
