Progression of pathological changes in the middle cerebellar peduncle by diffusion tensor imaging correlates with lesser motor gains after pontine infarction.

BACKGROUND: Wallerian degeneration in pyramidal tract following supratentorial stroke has been detected by some studies using diffusion tensor imaging (DTI), but the Wallerian degeneration in middle cerebellar peduncle after pontine infarction and its potential clinical significance remain to be confirmed.
METHODS: Seventeen patients with a recent focal pontine infarct underwent 3 DTIs at week 1 (W1), week 4 (W4), and week 12 (W12) after onset. Seventeen age-matched and gender-matched controls underwent DTI one time. Mean diffusivity and fractional anisotropy (FA) were measured in the basis pontis and bilateral middle cerebellar peduncles. Neurological deficit, motor deficit, functional independence, and limbs ataxia were assessed with the National Institutes of Health (NIH) Stroke Scale, Fugl-Meyer scale, Barthel Index, and the second part of International Cooperative Ataxia Rating Scale.
RESULTS: FA values at the bilateral middle cerebellar peduncles decreased significantly from W1 to W12 progressively (P<.01). The patients improved on the NIH Stroke Scale, Fugl-Meyer scale, and Barthel Index over time (P<.01). Greater absolute value of percentage reduction of FA at the bilateral middle peduncles, however, was associated with the less absolute value of percentage reduction of the NIH Stroke Scale and less increase in the Fugl-Meyer scale, as well as greater ataxia over time.
CONCLUSIONS: Wallerian degeneration in the middle cerebellar peduncle revealed by DTI may hinder the process of neurological recovery following a focal pontine infarct.