title: Preoperative and intraoperative diffusion tensor imaging-based fiber tracking in glioma surgery.
abstract: OBJECTIVE
  To investigate the intraoperative displacement of major white matter tracts during glioma resection by comparing preoperative and intraoperative diffusion tensor imaging-based fiber tracking.
  
  
  METHODS
  In 37 patients undergoing glioma surgery, preoperative and intraoperative diffusion tensor imaging was performed with a 1.5-T magnetic resonance scanner applying an echo-planar imaging sequence with six diffusion directions. For three-dimensional tractography, we implemented a knowledge-based multiple-region-of-interest approach applying user-defined seed regions in the color-coded maps of fractional anisotropy. Tracking was initiated in both the retrograde and orthograde directions according to the direction of the principal eigenvector in each voxel of the region of interest. The tractography results were also assigned color, applying the convention used in color-coded fractional anisotropy maps.
  
  
  RESULTS
  Preoperative and intraoperative fiber tracking was technically feasible in all patients. Fiber tract visualization gave a quick and intuitive overview of the displaced course of white matter tracts in three-dimensional space. Comparison of preoperative and intraoperative tractography depicted a marked shifting of major white matter tracts during glioma removal. Maximum white matter tract shifting ranged from -8 to +15 mm (+2.7 +/- 6.0 mm; mean +/- standard deviation); in 29.7%, an inward and in 62.2%, an outward shifting was detected.
  
  
  CONCLUSIONS
  Comparing preoperative and intraoperative fiber tracking visualizes a marked shifting and deformation of major white matter tracts because of tumor removal. This shifting emphasizes the need for an intraoperative update of navigation systems during resection of deep-seated tumor portions near eloquent brain areas. Fiber tracking is a method not only for preoperative neurosurgical visualization but also for further intraoperative planning.
authors.affiliation: Department of Neurosurgery, University Erlangen-Nürnberg, Erlangen, Germany. nimsky@nch.imed.uni-erlangen.de
authors.forename: Christopher
authors.initials: C
authors.lastname: Nimsky
authors.forename: Oliver
authors.initials: O
authors.lastname: Ganslandt
authors.forename: Peter
authors.initials: P
authors.lastname: Hastreiter
authors.forename: Ruopeng
authors.initials: R
authors.lastname: Wang
authors.forename: Thomas
authors.initials: T
authors.lastname: Benner
authors.forename: A Gregory
authors.initials: AG
authors.lastname: Sorensen
authors.forename: Rudolf
authors.initials: R
authors.lastname: Fahlbusch
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D005910:Glioma / Q000175:diagnosis* / Q000601:surgery*; D006801:Humans; D007430:Intraoperative Care; D008297:Male; D008875:Middle Aged; D011300:Preoperative Care; D015173:Supratentorial Neoplasms / Q000175:diagnosis* / Q000601:surgery*