Orthogonal diffusion-weighted MRI measures distinguish region-specific degeneration in cerebellar ataxia subtypes

The cerebellar peduncles are excellent candidates for composite indicators of regional degeneration in posterior fossa structures, as the peduncles show histopathological changes in degenerative ataxia. We postulate that magnetic resonance imaging will reveal evidence of disease specific peduncle degeneration through macrostructural (cross-sectional area) and microstructural (fractional anisotropy, mean diffusivity) measures. This study presents a "proof of principle" using orthogonal diffusion tensor imaging cross-sections of the cerebellar peduncles to distinguish categories of cerebellar disease.