[A case with pyramidal tract lesion suggesting Wallerian degeneration--analysis with diffusion coefficient]

Area of Science:

• Neuroimaging
• Neuropathology

Background:

• Cerebral infarction can lead to secondary degeneration of white matter tracts.
• Wallerian degeneration is a process of axonal and myelin breakdown distal to an injury.

Observation:

• A 55-year-old male presented with imaging findings 6 months post-left centrum semiovale infarction.
• T2-weighted MRI showed abnormal high signal intensity along the left pyramidal tract, extending from the centrum semiovale.
• CT revealed hypodensities in the left centrum semiovale and posterior limb of the internal capsule.

Findings:

• MRI demonstrated lesions consistent with demyelination, including high signal on T2/proton-weighted and low signal on T1-weighted images.
• Diffusion tensor imaging revealed increased diffusivity perpendicular to the pyramidal tract and altered diffusion anisotropy.
• These imaging characteristics suggest stage 2 Wallerian degeneration.

Implications:

• This case highlights the utility of advanced MRI techniques in characterizing white matter degeneration.
• Understanding the imaging patterns of Wallerian degeneration is crucial for diagnosing and managing post-stroke complications.
• The findings contribute to the neuropathological understanding of secondary tract degeneration.