A Study of Diffusion Tensor Imaging in Hirayama Disease

Area of Science:

• Neurology
• Neuroimaging
• Biomedical Engineering

Background:

• Hirayama disease (HD) is a motor neuron disease that can present with lower limb hyper-reflexia.
• Corticospinal tract dysfunction is a potential factor in HD, but its evaluation using diffusion tensor imaging (DTI) is understudied.

Purpose of the Study:

• To evaluate corticospinal tract function in Hirayama disease patients using DTI.
• To correlate DTI findings with clinical manifestations such as lower limb hyper-reflexia.

Main Methods:

• Patients diagnosed with Hirayama disease based on clinical and electromyography findings were included.
• Diffusion tensor imaging (DTI) was performed to assess the corticospinal tract at specific brain regions (internal capsule, cerebral peduncle, pons, pyramid).
• Clinical data including age, disease duration, and presence of hyper-reflexia were collected and correlated with DTI results.

Main Results:

• No significant differences in DTI metrics (apparent diffusion coefficient, fractional anisotropy, axial diffusivity, radial diffusivity) were observed in the internal capsule, cerebral peduncle, pons, or pyramid between HD patients and controls.
• DTI findings did not differ between the more and less affected sides of the body in HD patients.
• Fractional anisotropy showed no correlation with lower limb hyper-reflexia or spinal cord atrophy.

Conclusions:

• Diffusion tensor imaging (DTI) of the brain did not demonstrate corticospinal tract involvement in patients with Hirayama disease.
• The study suggests that the corticospinal tract in the brain may not be the primary affected area in Hirayama disease, despite potential clinical signs like hyper-reflexia.