Wallerian degeneration of the corticospinal tracts: postmortem MR-pathologic correlations.

Postmortem magnetic resonance (MR) images were correlated with the histological findings in two autopsy-proven cases of Wallerian degeneration of the corticospinal and corticopontine tracts associated with cerebral embolic infarction. T2 hyperintensities seen in Wallerian degeneration showed vacuolation of myelin in the early stage, and marked loss of myelin and axons with macrophages in the subacute and chronic stages. Similar T2 hyperintensities seen in the different stages of Wallerian degeneration reflect different histological findings.