Magnetic resonance microscopy of the C57BL mouse brain

With the rapid progression in gene technologies, transgenic, targeted, and chemically induced mutations in mice are continually created. The major goa l of these studies is to understand and characterize the effects of genotyp e on anatomy, physiology, and behavior and ultimately the role of genotype in development of disease. The demand for imaging techniques with high spat ial resolution potential is rising because such imaging tools would expedit e anatomical phenotyping in the genetically altered mice. Magnetic resonanc e microscopy (MRM) is a noninvasive, inherently three-dimensional (3D) imag ing technique capable of visualizing several anatomical structures in the s mall mouse. The 3D nature of MRM also allows for interpretation of complex spatial relationships between substructures, which is important when phenot yping anatomically. The goal of this paper is to systematically describe th ree major brain regions in the C57BL/6J mouse at microanatomical spatial re solution ranges using in vitro MRM. We explore different MR contrast parame ters, voxel sizes, and signal-to-noise ratios to best characterize C57BL/6J mouse brain microstructure by MRM. Further, we compare all MRM images with Nissl-stained brain sections. Major findings were as follows: T2* MR image s visualized several gross anatomical regions in the mouse brain but not, f or example, subregions within the hippocampus. Diffusion proton stains on t he other hand were superior to T2* MR images and delineated many subregions within the hippocampus proper. Finally, contrast enhancement facilitated v isualization of hippocampal anatomy on the T2* MR images. The results of th is study are part of an ongoing initiative at our Center focused on creatin g a complete C57BL/6J mouse anatomical 3D image database by MRM. (C) 2000 A cademic Press.