Correlation of Fractional Anisotropy With Motor Recovery in Patients With Stroke After Postacute Rehabilitation

Objective: To investigate the relation between fractional anisotropy (FA), a suggested biomarker for tissue integrity, and motor recovery in patients with stroke after postacute rehabilitation. Design: Retrospective study. Setting: Acute rehabilitation hospital. Participants: Subjects (N=43) diagnosed with ischemic stroke (n=28) and hemorrhagic stroke (n=15). The average age for subjects was 68 +/- 14 years. Interventions: Magnetic resonance imaging and diffusion tensor imaging were conducted on all patients. Main Outcome Measures: The admission and discharge motor subscores of the FIM were obtained from medical records, and relative gain was calculated using the Montebello Rehabilitation Factor Score (MRFS). K-means cluster analysis (K=3) using both the MRFS and the gain of the FIM motor subscore (Delta FIM) was performed. Analysis of variance was used to determine the difference in FA among the clusters. Spearman analysis was conducted to examine the relation between FA, Delta FIM, and MRFS in each cluster. Results: FA was significantly higher in the clusters of good and moderate recovery in the corticospinal tract (CST), peduncle, and posterior limb of the internal capsule bilaterally (all P<.05) compared with the poor recovery group. Significant positive correlations were observed in multiple regions along the CST between FA, Delta FIM, and MRFS in the clusters of good and moderate recovery, but not in the poor recovery group. Conclusions: Our results showed an association between FA values within the corticospinal tract and motor recovery in patients with stroke undergoing postacute rehabilitation. This finding may help to identify novel targets for new interventions to promote stroke recovery. (C) 2016 by the American Congress of Rehabilitation Medicine