title: Visualization of the pyramidal tract in glioma surgery by integrating diffusion tensor imaging in functional neuronavigation.
abstract: OBJECTIVE
  The aim of this study was to investigate whether diffusion tensor imaging (DTI) can be integrated into functional navigation for the intraoperative visualization of the pyramidal tract.
  
  
  METHODS
  A single-shot spin-echo diffusion-weighted echo planar imaging sequence on a 1.5 T magnetic resonance (MR) scanner was used for DTI. One null image and six diffusion-weighted images (high B value 1 000 mm/s (2)) were obtained. Color-encoded fractional anisotropy maps of the principal eigenvector rendered as a boxoid within each voxel were used for segmentation of the pyramidal tract. The segmented images were rigidly registered with a T(1)-weighted gradient echo 3D dataset for navigation in 16 patients with gliomas. In tumors adjacent to the motor cortex (n = 6) data from functional MR imaging were co-registered.
  
  
  RESULTS
  The whole DTI processing lasted about 25-30 minutes in each case. In all cases DTI could be integrated into the navigational dataset resulting in an intraoperative visualization of the pyramidal tract by microscope-based navigation. Navigational accuracy measured as the target registration error was 1.2 +/- 0.46 mm. Registration of fractional anisotropy maps with the 3D navigational dataset was possible with an error of less than 2 mm. Co-registration with fMRI was consistent with DTI data. A neurological deterioration was observed only in one patient.
  
  
  CONCLUSIONS
  DTI can be reliably integrated into navigational datasets. Thus, microscope-based neuronavigation can be used for an intraoperative visualization of the course of the pyramidal tract. However, a possible shifting of the pyramidal tract has to be taken into account after major tumor parts are removed.
authors.affiliation: Department of Neurosurgery, University Erlangen-Nürnberg, Erlangen, Germany. nimsky@nch.imed.uni-erlangen.de
authors.forename: C
authors.initials: C
authors.lastname: Nimsky
authors.forename: P
authors.initials: P
authors.lastname: Grummich
authors.forename: A G
authors.initials: AG
authors.lastname: Sorensen
authors.forename: R
authors.initials: R
authors.lastname: Fahlbusch
authors.forename: O
authors.initials: O
authors.lastname: Ganslandt
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001254:Astrocytoma / Q000473:pathology / Q000601:surgery; D001931:Brain Mapping; D001932:Brain Neoplasms / Q000473:pathology / Q000601:surgery*; D003399:Craniotomy; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D005909:Glioblastoma / Q000473:pathology / Q000601:surgery; D005910:Glioma / Q000473:pathology / Q000601:surgery*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007432:Intraoperative Period; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D019635:Neurosurgical Procedures; D011712:Pyramidal Tracts / Q000473:pathology*