title: Pontine infarction: diffusion-tensor imaging of motor pathways-a longitudinal study.
abstract: OBJECTIVE
  To investigate the dynamic evolution of diffusion indexes in the corticospinal tract (CST) distal to a pontine infarct by using diffusion-tensor imaging, to determine the relationship of these indexes with clinical prognosis, and to explore the structural changes in the motor pathway during recovery.
  
  
  METHODS
  This study was approved by the institutional ethics committee, and written informed consent was obtained from each participant. Seventeen patients with pontine infarct underwent five diffusion-tensor imaging examinations during a period of 6 months (within 7 days of onset, 14, 30, 90, and 180 after onset). Fractional anisotropic values were measured in the medulla, cerebral peduncle, internal capsule, and centrum semiovale. Fractional anisotropic values of the CST in the ipsilateral side of the infarct were compared with those in the contralateral sides and those in control subjects by using the Student t test and one-way analysis of variance, and their relationships with clinical scores were analyzed by using Pearson correlation analysis. Reconstructions of the CST were performed. Structural changes of the damaged CST were followed up.
  
  
  RESULTS
  Fractional anisotropic ratios in the CST above the pons decreased significantly compared with those in the contralateral side and those in control subjects within 7 days, on day 14, and on day 30 after onset (P < .001). Fractional anisotropic ratios above the pons on day 14 correlated positively with Fugl-Meyer scores on day 90 (r = 0.771, P < .001) and day 180 (r = 0.730, P = .001). Follow-up diffusion-tensor tractographic images showed regeneration and reorganization of the motor pathways.
  
  
  CONCLUSIONS
  Secondary degeneration of the CST can be detected at diffusion-tensor imaging in the early stages after pontine infarction, which could help predict the motor outcomes. Diffusion-tensor tractography can allow detection of regeneration and reorganization of the motor pathways during recovery.
authors.affiliation: From the Departments of Radiology (M.Z., J.L., D.R., Z.Z., K.L.) and Neurology (Q.M.), Xuanwu Hospital of Capital Medical University, 45 Changchun Street, 100053 Beijing, China; Beijing Key Laboratory of Magnetic Resonance Imaging and Brain Informatics, Beijing, China (M.Z., J.L., D.R., Z.Z., K.L.); State Key Laboratory of Cognitive Neuroscience and Learning and IDG/McGovern Institute for Brain Research, Beijing Normal University, Beijing, China (Q.L., N.S., Y.H.); Center for Collaboration and Innovation in Brain and Learning Sciences, Beijing Normal University, Beijing, China (Q.L., N.S., Y.H.); and Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology and Department of Psychiatry, Massachusetts General Hospital, Charlestown, Mass (H.L.).
authors.forename: Miao
authors.initials: M
authors.lastname: Zhang
authors.forename: Qixiang
authors.initials: Q
authors.lastname: Lin
authors.forename: Jie
authors.initials: J
authors.lastname: Lu
authors.forename: Dongdong
authors.initials: D
authors.lastname: Rong
authors.forename: Zhilian
authors.initials: Z
authors.lastname: Zhao
authors.forename: Qingfeng
authors.initials: Q
authors.lastname: Ma
authors.forename: Hesheng
authors.initials: H
authors.lastname: Liu
authors.forename: Ni
authors.initials: N
authors.lastname: Shu
authors.forename: Yong
authors.initials: Y
authors.lastname: He
authors.forename: Kuncheng
authors.initials: K
authors.lastname: Li
mesh_terms: D000328:Adult; D000368:Aged; D016880:Anisotropy; D020520:Brain Infarction / Q000175:diagnosis*; D056324:Diffusion Tensor Imaging; D004525:Efferent Pathways; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D011149:Pons / Q000098:blood supply*; D011446:Prospective Studies; D011712:Pyramidal Tracts