Abstract: Objective To explore brain plasticity of upper extremities motor function recovery after stroke with diffusion tensor imaging (DTI). Methods 25 stroke patients with internal capsule lesions and affected corticospinal tract (CST), 4-8 weeks after onset, were divided randomly into rehabilitation group (n=13) and control group (n=12). Both groups received routine medication and the rehabilitation group also received rehabilitation. All the patients were scanned with DTI and assessed with upper extremity Fugl-Myer Assessment (UE-FMA) before and 3 months after treatment. The fractional anisotropy (FA), FA ratio (rFA) and FA asymmetry (FAasy) in cerebral peduncle, posterior limb of internal capsule (PLIC) and corona radiate were obtained. The bilateral corticospinal tracts were reconstructed with diffusion tensor tractography. Results The scores of UE-FMA increased in both groups after treatment (P<0.05), and increased more in the rehabilitation group than in the control group (P<0.05). There was significant difference in FA, rFA and FAasy in the corona radiate section of CST after treatment in the rehabilitation group (P<0.05), but was not in the cerebral peduncle and PLIC section. However, there was no significant differences in FA, rFA and FAasy in the control group. The ipsilesional CST fibers were more compact after treatment in the rehabilitation group. Conclusion Rehabilitation can improve the upper extremities function recovery after stroke, which may associated with the repairment of CST in the corona radiate section.

Key words: stroke, upper extremities, motor function, diffusion tensor imaging, magnetic resonance imaging, rehabilitation, brain plasticity