title: FIBRASCAN: a novel method for 3D white matter tract reconstruction in MR space from cadaveric dissection.
abstract: BACKGROUND
  Diffusion tractography relies on complex mathematical models that provide anatomical information indirectly, and it needs to be validated. In humans, up to now, tractography has mainly been validated by qualitative comparison with data obtained from dissection. No quantitative comparison was possible because Magnetic Resonance Imaging (MRI) and dissection data are obtained in different reference spaces, and because fiber tracts are progressively destroyed by dissection. Here, we propose a novel method and software (FIBRASCAN) that allow accurate reconstruction of fiber tracts from dissection in MRI reference space.
  
  
  METHODS
  Five human hemispheres, obtained from four formalin-fixed brains were prepared for Klingler's dissection, placed on a holder with fiducial markers, MR scanned, and then dissected to expose the main association tracts. During dissection, we performed iterative acquisitions of the surface and texture of the specimens using a laser scanner and two digital cameras. Each texture was projected onto the corresponding surface and the resulting set of textured surfaces was coregistered thanks to the fiducial holders. The identified association tracts were then interactively segmented on each textured surface and reconstructed from the pile of surface segments. Finally, the reconstructed tracts were coregistered onto ex vivo MRI space thanks to the fiducials. Each critical step of the process was assessed to measure the precision of the method.
  
  
  RESULTS
  We reconstructed six fiber tracts (long, anterior and posterior segments of the superior longitudinal fasciculus; Inferior fronto-occipital, Inferior longitudinal and uncinate fasciculi) from cadaveric dissection and ported them into ex vivo MRI reference space. The overall accuracy of the method was of the order of 1mm: surface-to-surface registration=0.138mm (standard deviation (SD)=0.058mm), deformation of the specimen during dissection=0.356mm (SD=0.231mm), and coregistration surface-MRI=0.6mm (SD=0.274mm). The spatial resolution of the method (distance between two consecutive surface acquisitions) was 0.345mm (SD=0.115mm).
  
  
  CONCLUSIONS
  This paper presents the robustness of a novel method, FIBRASCAN, for accurate reconstruction of fiber tracts from dissection in the ex vivo MR reference space. This is a major step toward quantitative comparison of MR tractography with dissection results.
authors.affiliation: INSERM U930 Imagerie et Cerveau, Université François-Rabelais de Tours, Tours, France; Université François-Rabelais de Tours, Laboratoire d'Anatomie, Tours, France; CHRU de Tours, Service de Neurochirurgie, Tours, France. Electronic address: ilyess.zemmoura@univ-tours.fr.
authors.forename: Ilyess
authors.initials: I
authors.lastname: Zemmoura
authors.affiliation: INSERM U930 Imagerie et Cerveau, Université François-Rabelais de Tours, Tours, France; Université François-Rabelais de Tours, Laboratoire d'Informatique, EA6300 Tours, France.
authors.forename: Barthélémy
authors.initials: B
authors.lastname: Serres
authors.affiliation: INSERM U930 Imagerie et Cerveau, Université François-Rabelais de Tours, Tours, France.
authors.forename: Frédéric
authors.initials: F
authors.lastname: Andersson
authors.affiliation: INSERM U930 Imagerie et Cerveau, Université François-Rabelais de Tours, Tours, France.
authors.forename: Laurent
authors.initials: L
authors.lastname: Barantin
authors.affiliation: INSERM U930 Imagerie et Cerveau, Université François-Rabelais de Tours, Tours, France.
authors.forename: Clovis
authors.initials: C
authors.lastname: Tauber
authors.affiliation: INSERM U930 Imagerie et Cerveau, Université François-Rabelais de Tours, Tours, France.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Filipiak
authors.affiliation: INSERM U930 Imagerie et Cerveau, Université François-Rabelais de Tours, Tours, France; CHRU de Tours, Service de Neuroradiologie, Tours, France.
authors.forename: Jean-Philippe
authors.initials: JP
authors.lastname: Cottier
authors.affiliation: Université François-Rabelais de Tours, Laboratoire d'Informatique, EA6300 Tours, France.
authors.forename: Gilles
authors.initials: G
authors.lastname: Venturini
authors.affiliation: INSERM U930 Imagerie et Cerveau, Université François-Rabelais de Tours, Tours, France; Université François-Rabelais de Tours, Laboratoire d'Anatomie, Tours, France; CHRU de Tours, Service de Neurochirurgie, Tours, France.
authors.forename: Christophe
authors.initials: C
authors.lastname: Destrieux
mesh_terms: D002102:Cadaver; D002540:Cerebral Cortex / Q000033:anatomy & histology*; D056324:Diffusion Tensor Imaging / Q000379:methods; D004210:Dissection; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods*; D009434:Neural Pathways / Q000033:anatomy & histology*; D012984:Software; D066127:White Matter / Q000033:anatomy & histology*
keywords: Comparison dissection tractography; Diffusion tractography; Fiber dissection; Fiber tracts; Tractography validation