Quantitative Diffusion Tensor Imaging of White Matter Microstructure in Dog Brain at 7T

Abstract

The purpose of this study is to develop a noninvasive quantitative imaging scheme to assess the functional microanatomy of dog brain using high resolution diffusion tensor imaging (DTI) at 7-Tesla (T) magnetic resonance imaging (MRI) scanner. Diffusion weighted images (DWIs) along 25 diffusion-encoding directions, combined with T2 weighted images, were acquired using the standard spin-echo diffusion encoding scheme to determine the diffusion tensor matrix. Three diffusion indices: fractional anisotropy (FA), Trace/3 apparent diffusion coefficient (ADC), and volume ratio (VR) were measured within seven representative regions of interest (ROIs) from internal capsule, corpus callosum, caudate nucleus, hippocampus, thalamus, fornix, and cerebral cortex. Experimental results show much higher scalar contrast and more accurate fiber structures based on the FA weighted color map and fiber orientation map, indicating this high angular DTI technique at 7T is an accurate scheme to map the microstructures in fixed dog brains, which is also applicable for studying the functional microanatomy of other animal models.