title: Boundary estimation of fiber bundles derived from diffusion tensor images.
abstract: OBJECTIVE
  Diffusion tensor imaging (DTI) is a non-invasive imaging technique that allows estimating the location of white matter tracts based on the measurement of water diffusion properties. Using DTI data, the fiber bundle boundary can be determined to gain information about eloquent structures, which is of major interest for neurosurgical interventions. In this paper, a novel approach for boundary estimation is presented.
  
  
  METHODS
  DTI in combination with diverse segmentation algorithms allows estimating the position and course of fiber tracts in the human brain. For additional information about the expansion of the fiber bundle, the introduced iterative approach uses the centerline of a tracked fiber bundle between two regions of interest (ROI). After sampling along this centerline, rays are sent out radially, discrete 2D contours are calculated, and the fiber bundle boundary is estimated in a stepwise manner. For this purpose, each ray is analyzed using several criteria, including anisotropy parameters and angle parameters, to find the boundary point.
  
  
  RESULTS
  The novel method for automatically calculating the boundaries has been applied to several artificially generated DTI datasets. Multiple parameters were varied: number of rays per plane, sampling rate and sampled points along the rays. For the DTI data used in the experiments, the method yielded a dice similarity coefficient (DSC) between 74.7 and 91.5%.
  
  
  CONCLUSIONS
  In this paper, a novel approach to retrieve significant information about the fiber bundle boundary from DTI data is presented. The method is a contribution to gather important knowledge about high-risk structures in neurosurgical interventions.
authors.affiliation: Department of Neurosurgery, University of Marburg, Baldingerstrasse, 35033 Marburg, Germany. bauermi@med.uni-marburg.de
authors.forename: Miriam Helen Anna
authors.initials: MH
authors.lastname: Bauer
authors.forename: Sebastiano
authors.initials: S
authors.lastname: Barbieri
authors.forename: Jan
authors.initials: J
authors.lastname: Klein
authors.forename: Jan
authors.initials: J
authors.lastname: Egger
authors.forename: Daniela
authors.initials: D
authors.lastname: Kuhnt
authors.forename: Bernd
authors.initials: B
authors.lastname: Freisleben
authors.forename: Horst Karl
authors.initials: HK
authors.lastname: Hahn
authors.forename: Christopher
authors.initials: C
authors.lastname: Nimsky
mesh_terms: D000465:Algorithms; D001921:Brain / Q000033:anatomy & histology*; D056324:Diffusion Tensor Imaging / Q000379:methods*; D006801:Humans; D009413:Nerve Fibers, Myelinated / Q000737:chemistry*
references.citation: Acad Radiol. 2004 Feb;11(2):178-89
references.pmid: 14974593
references.citation: Stereotact Funct Neurosurg. 2009;87(1):50-60
references.pmid: 19174621
references.citation: NMR Biomed. 2002 Nov-Dec;15(7-8):468-80
references.pmid: 12489096
references.citation: Magn Reson Med. 2000 Aug;44(2):283-91
references.pmid: 10918328
references.citation: Neurosci Lett. 2002 Oct 25;332(1):45-8
references.pmid: 12377381
references.citation: NMR Biomed. 2002 Nov-Dec;15(7-8):456-67
references.pmid: 12489095
references.citation: Magn Reson Med. 2004 Feb;51(2):413-7
references.pmid: 14755670
references.citation: J Magn Reson Imaging. 2001 Apr;13(4):534-46
references.pmid: 11276097