Secondary degeneration detected by combining voxel-based morphometry and tract-based spatial statistics in subcortical strokes with different outcomes in hand function

BACKGROUND AND PURPOSE: Secondary degeneration of the pyramidal tract after focal motor pathway stroke has been observed by diffusion tensor imaging. However, the relationships between outcomes in hand function and secondary degeneration in widespread regions are not well understood. For the first time, we investigated the differences of secondary degeneration across the whole brain between subgroups of patients with stroke. MATERIALS AND METHODS: We selected 23 patients who had a subcortical stroke in the left motor pathway and displayed only motor deficits. The patients were divided into 2 subgroups: CPH (11 patients) and PPH (12 patients). Twelve healthy controls matched for age and handedness were also recruited.Weused both optimized VBM and TBSS to explore differences of FA across the whole brain between CPH and PPH. Furthermore, ROI analysis was carried out in the identified regions detected by VBM analysis to further quantify the degree of secondary degeneration in the CPH and PPH and compare these with healthy controls. RESULTS: Compared with PPH, FA was significantly decreased in the CPH in widespread regions of the motor system remote from the primary lesion, including the ipsilesional brain stem, medial frontal gyrus, precentral gyrus, superior temporal gyrus, supplementary motor area, and contralesional postcentral gyrus. In addition, FA within these identified regions correlated with Fugl-Meyer Assessment scores (handwrist). CONCLUSIONS: This study suggests a potential biomarker for outcome differences in hand function after subcortical stroke.