Nerve Fiber Bundle Damage in Spinocerebellar Degeneration on Diffusion Tensor Imaging

This study aimed to investigate nerve fiber bundle damage associated with spinocerebellar degeneration, a dominant inherited neurological disorder, using magnetic resonance imaging (MRI) with diffusion tensor imaging (DTI).

Four cases of spinocerebellar degeneration and ten matched healthy subjects were retrospectively enrolled. DTI software was used for processing and analysis.

All patients had an abnormal spinocerebellar ataxia (SCA) type 3 gene mutation, with cerebellar and brainstem atrophy, a decreased signal in the pons and projection fibers. Significant interruption and destruction were revealed in the midline of the cerebellar peduncle, cerebellar arcuate fibers, and the spinothalamic and spinocerebellar tracts. Significant (p <0.05) decreases were detected in FA values in the cerebellar peduncle (0.51±0.04 vs. 0.68±0.02), cerebellar arcuate fibers (0.37±0.08 vs. 0.51±0.05), spinothalamic tract (0.42±0.03 vs. 0.49±0.05), and spinocerebellar tract (0.44±0.06 vs. 0.52±0.06) compared with healthy controls. Compared with healthy controls, significant (p <0.05) increases were detected in ADC values in the cerebellar peduncle (0.84±0.11 vs. 0.67±0.03), cerebellar arcuate fibers (0.87±0.12 vs. 0.66±0.05), spinothalamic tract (0.89±0.13 vs. 0.70±0.03) within the brainstem, and spinocerebellar tract (0.79±0.07 vs. 0.69±0.06).

The MRI DTI technique provides sufficient information for studying spinocerebellar degeneration and for conducting further research on its etiology and diagnosis. Some limitations were present, including the retrospective and single-center study design, a limited patient sample, and enrollment of only Chinese patients.

The MRI DTI technique can clearly demonstrate the degree of damage to nerve fiber bundles in the cerebellum and the adjacent relationship between the fiber bundles entering and exiting the cerebellum in patients with spinocerebellar degeneration.