The MT pool size ratio and the DTI radial diffusivity may reflect the myelination in shiverer and control mice

A quantitative magnetization transfer (qMT) technique was employed to quantify the ratio of the sizes of the bound and free water proton pools in ex vivo mouse brains. The goal was to determine the pool size ratio sensitivity to myelin. Fixed brains from both shiverer mice and control littermates were imaged. The pool size ratio in the corpus callosum of shiverer mice was substantially lower than that in the control mice, while there was no distinguishable difference in the pool size ratio in the gray matter. These results correlate with diffusion tensor imaging (DTI) derived radial diffusivity which previously was shown to reflect myelin integrity in this animal model. Histological study reveals the presence of myelin in control mice white matter and the absence of myelin in shiverer mice white matter, supporting the qMT and DTI results. Our findings support the view that qMT may be used for estimating myelin integrity.