title: Anatomical MRI templates of tree shrew brain for volumetric analysis and voxel-based morphometry.
abstract: BACKGROUND
  Tree shrews are close relatives of primates, and are increasingly used as models in the research of vision, social stress and neurological/psychiatric diseases. However, neuroimaging techniques, for example magnetic resonance (MR) imaging, are only rarely applied to this species to study the structure and function of the brain. A template MR image set, which is essential for morphometry/volumetric analysis, of tree shrew brain has been lacking in the literature.
  
  
  METHODS
  High-resolution anatomical MR images and diffusion tensor images of the brain were acquired from male Chinese tree shrews (Tupaia belangeri chinensis), and resampled to an isotropic resolution of 200 μm × 200 μm × 200 μm. Population-based image templates of tree shrew brain, including gray matter/white matter/cerebrospinal fluid probability maps and a fractional anisotropy template, were constructed at this spatial resolution, all in a reference space. Digital masks of representative anatomical structures, including hippocampus, amygdala and cingulum bundle, were created.
  
  
  RESULTS
  With the templates constructed, the volumes of bilateral hippocampus and amygdala were measured using a template-facilitated semi-automated approach to be 59.8 ± 8.3 and 64.3 ± 3.4 mm(3), respectively.
  
  
  CONCLUSIONS
  For the first time, high-resolution MR image templates of tree shrew brain were reported. The average volume of bilateral hippocampus measured with the template-facilitated semi-automated approach was found to be similar to the result obtained by the much more labor-intensive manual approach.
  
  
  CONCLUSIONS
  The MR image templates obtained in this study are useful for analyzing neuroimage data of tree shrew brain. The templates are freely available to the scientific community upon request.
authors.affiliation: Wuhan Center for Magnetic Resonance, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan, China; Graduate University of Chinese Academy of Sciences, Beijing, China.
authors.forename: Shuxia
authors.initials: S
authors.lastname: Wang
authors.forename: Dai
authors.initials: D
authors.lastname: Shan
authors.forename: Jiankun
authors.initials: J
authors.lastname: Dai
authors.forename: Haichen
authors.initials: H
authors.lastname: Niu
authors.forename: Yuanye
authors.initials: Y
authors.lastname: Ma
authors.forename: Fuchun
authors.initials: F
authors.lastname: Lin
authors.forename: Hao
authors.initials: H
authors.lastname: Lei
mesh_terms: D000716:Anatomy, Artistic; D000818:Animals; D001271:Atlases as Topic; D001921:Brain / Q000033:anatomy & histology*; D056324:Diffusion Tensor Imaging; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D014418:Tupaiidae / Q000033:anatomy & histology*
keywords: Brain; Magnetic resonance imaging; Template; Tree shrew; Volumetric measurement