title: Altered white matter microstructural connectivity in cluster headaches: a longitudinal diffusion tensor imaging study.
abstract: BACKGROUND
  Functional and structural disruptions to the pain matrix, which may involve changes in white matter (WM) pathways connecting the pain-processing system and hypothalamus, have been implicated in the pathophysiology of cluster headache (CH). However, previous studies have obtained inconclusive results regarding WM changes in CH, and WM variations between "in-bout" and "out-of-bout" periods of CH remain to be determined.
  
  
  METHODS
  Multiple diffusivity indices obtained by diffusion tensor imaging (DTI) and post-hoc probabilistic tractography were used to elucidate CH pathophysiology.
  
  
  RESULTS
  Compared to healthy participants, in-bout CH patients showed regionally higher absolute (radial and mean) diffusivities in the left medial frontal gyrus and frontal sub-gyrus and lower absolute (axial, radial and mean) diffusivities in the right parahippocampal gyrus of the limbic lobe. These changes during the in-bout period generally persisted in the out-of-bout period, except for the left cerebellar tonsil. Post-hoc probabilistic tractography showed highly consistent anatomical connections between these altered areas and the hypothalamus across participants.
  
  
  CONCLUSIONS
  Distinct WM changes were observed in episodic CH. Connections between the pain-modulation areas and hypothalamus may be involved in CH pathophysiology.
authors.affiliation: Institute of Neuroscience, National Yang-Ming University, Taiwan Brain Research Center, National Yang-Ming University, Taiwan.
authors.forename: Kun-Hsien
authors.initials: KH
authors.lastname: Chou
authors.affiliation: Institute of Brain Science, National Yang-Ming University, Taiwan Department of Neurology, Tri-Service General Hospital, National Defense Medical Center, Taiwan.
authors.forename: Fu-Chi
authors.initials: FC
authors.lastname: Yang
authors.affiliation: Department of Neurology, National Yang-Ming University, Taiwan Department of Neurology, Taipei Veterans General Hospital, Taiwan.
authors.forename: Jong-Ling
authors.initials: JL
authors.lastname: Fuh
authors.affiliation: Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, Taiwan.
authors.forename: Chu-Chung
authors.initials: CC
authors.lastname: Huang
authors.affiliation: Department of Radiology, National Yang-Ming University, Taiwan Department of Radiology, Taipei, Veterans General Hospital, Taiwan.
authors.forename: Jiing-Feng
authors.initials: JF
authors.lastname: Lirng
authors.affiliation: Brain Research Center, National Yang-Ming University, Taiwan Institute of Brain Science, National Yang-Ming University, Taiwan Department of Neurology, National Yang-Ming University, Taiwan Department of Neurology, Taipei Veterans General Hospital, Taiwan.
authors.forename: Yung-Yang
authors.initials: YY
authors.lastname: Lin
authors.affiliation: Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, Taiwan.
authors.forename: Pei-Lin
authors.initials: PL
authors.lastname: Lee
authors.affiliation: Department of Radiology, Tri-Service General Hospital, National Defense Medical Center, Taiwan.
authors.forename: Hung-Wen
authors.initials: HW
authors.lastname: Kao
authors.affiliation: Institute of Neuroscience, National Yang-Ming University, Taiwan Brain Research Center, National Yang-Ming University, Taiwan Institute of Brain Science, National Yang-Ming University, Taiwan Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, Taiwan sjwang@vghtpe.gov.tw cplin@ym.edu.tw.
authors.forename: Ching-Po
authors.initials: CP
authors.lastname: Lin
authors.affiliation: Brain Research Center, National Yang-Ming University, Taiwan Institute of Brain Science, National Yang-Ming University, Taiwan Department of Neurology, National Yang-Ming University, Taiwan Department of Neurology, Taipei Veterans General Hospital, Taiwan sjwang@vghtpe.gov.tw cplin@ym.edu.tw.
authors.forename: Shuu-Jiun
authors.initials: SJ
authors.lastname: Wang
mesh_terms: D000328:Adult; D003027:Cluster Headache / Q000473:pathology*; D056324:Diffusion Tensor Imaging; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008297:Male; D008875:Middle Aged; D009434:Neural Pathways / Q000473:pathology*
keywords: Cluster headache; diffusion tensor imaging; diffusivity indices; pain matrix; probabilistic tractography