Cerebellar lesions in multiple system atrophy: postmortem MR imaging-pathologic correlations

Area of Science:

• Neuropathology
• Neuroimaging
• Multiple System Atrophy Research

Background:

• Cerebellar lesions, including atrophy and white matter T2-hyperintensities, are hallmarks of multiple system atrophy (MSA).
• Understanding the correlation between imaging findings and histological changes is crucial for diagnosing and characterizing MSA pathology.

Purpose of the Study:

• To correlate magnetic resonance imaging (MRI) findings with histological evidence in the cerebellar lesions of multiple system atrophy (MSA).
• To elucidate the pathological basis of T2-hyperintensities and hypointensities observed in the cerebellum of MSA patients.

Main Methods:

• Postmortem T2-weighted MRI at 1.5T was performed on 7 cases with pathologically confirmed MSA.
• MR imaging findings of cerebellar cortices and deep white matter dentate nucleus regions were systematically compared with corresponding histological findings.

Main Results:

• Three types of cerebellar changes were identified: no atrophy/signal changes, atrophy with patchy/confluent white matter hyperintensities, and atrophy with diffuse white matter hyperintensities.
• Cerebellar white matter atrophy was more pronounced than cortical atrophy. White matter hyperintensities corresponded histologically to loss of myelinated fibers and gliosis.
• Hypointensities in the dentate nucleus regions were associated with diffuse ferritin deposition within preserved nuclei and surrounding white matter.

Conclusions:

• Cerebellar white matter hyperintensities on MRI reflect degenerated white matter characterized by myelin loss and gliosis in MSA.
• Hypointensities in the dentate nucleus region are indicative of ferritin deposition in preserved neural structures.
• The pathological changes, particularly degeneration, are more severe in the cerebellar white matter compared to the cerebellar cortices in MSA.