Background: Information on microstructural integrity of cerebral white matter (WM) has been suggested as a promising marker to explain post-stroke recovery beyond clinical measures and focal tissue damage. Especially early dynamic post-stroke WM changes might be promising to improve prediction of outcome.
Methods: We investigated 42 patients (mean age=66.5 years, 40% female, median admission NIHSS=9.5) with a symptomatic MRI-confirmed middle cerebral artery infarction in the acute stage (1-3 days after symptom onset) and after three months. All patients received recanalization therapy (thrombolysis and/or thrombectomy) and underwent neurological examination and dedicated brain 3T-MRI. 15 healthy controls (mean age=57.3 years) were also scanned twice.
Results: Patients showed significantly lower WM integrity, as assessed by fractional anisotropy (FA), in the hemisphere with acute infarction 1-3 days post-stroke, which further decreased within three months in patients compared to controls. 
A regression model including baseline information showed that the modified Rankin Scale and mean FA of the genu of the corpus callosum explained 53.3% of variance of stroke recovery, without contribution of lesion volume. Furthermore, early dynamic FA changes of the corpus callosum within the first three months post-stroke independently predicted stroke recovery.
Conclusions: Information from advanced MRI measures on changes in WM integrity days after acute stroke, as well as subsequent early dynamic WM degeneration beyond lesion location and extent enhance our understanding of post-stroke reorganization in the affected hemisphere and contribute to an improved prediction of recovery.

EARLY CHANGES IN WHITE MATTER INTEGRITY ARE ASSOCIATED WITH STROKE RECOVERY