Changes in regional brain volume three months after stroke

Introduction: Little is known about changes in regional brain volume after stroke. We investigated cortical thickness changes over 3 months in a group of stroke patients compared with controls.

Material and methods: Patients with acute hemispheric stroke were studied within 3h of stroke onset and serially over 3 months. We compared the acute and 3 month scans with independently acquired control images. High resolution isotropic T1 images were analyzed using FreeSurfer V5.0, comparing regional average cortical thickness, hippocampal and thalamic volumes. Stroke patient results were analyzed separately for ipsilesional and contralesional regions, whereas control results were averaged across hemisphere. Percentage change scores between the two time points were computed for each participant, and paired sample t-tests were used to assess significant change.

Results: 12 stroke patients (9 men, 7 left-hemispheric, mean age=65.1 years) and 10 control participants (5 men, mean age=67.2 years) were included. There were no significant differences between the 2 time points in global or regional average cortical thickness, or hippocampal and thalamic volume estimates for control subjects. Regional variability in patient data was demonstrated, particularly cortical thickness increases in contralesional paracentral, superior frontal and insular regions, areas known to be activated in functional MRI studies of motor recovery. A significant reduction in thalamic volume was also found, most apparent ipsilesionally.

Conclusions: Post-stroke changes in regional cortical thickness are demonstrable even over short time-frames. Contralesional cortical thickness increases may represent compensatory mechanisms. Significant reductions in thalamic volume may represent evidence of early post-stroke atrophy. Further studies are required to confirm and extend these preliminary results.