title: Impact of fMRI-guided advanced DTI fiber tracking techniques on their clinical applications in patients with brain tumors.
abstract: BACKGROUND
  White matter tractography based on diffusion tensor imaging has become a well-accepted non-invasive tool for exploring the white matter architecture of the human brain in vivo. There exist two main key obstacles for reconstructing white matter fibers: firstly, the implementation and application of a suitable tracking algorithm, which is capable of reconstructing anatomically complex fascicular pathways correctly, as, e.g., areas of fiber crossing or branching; secondly, the definition of an appropriate tracking seed area for starting the reconstruction process. Large intersubject, anatomical variations make it difficult to define tracking seed areas based on reliable anatomical landmarks. An accurate definition of seed regions for the reconstruction of a specific neuronal pathway becomes even more challenging in patients suffering from space occupying pathological processes as, e.g., tumors due to the displacement of the tissue and the distortion of anatomical landmarks around the lesion.
  
  
  METHODS
  To resolve the first problem, an advanced tracking algorithm, called advanced fast marching, was applied in this study. The second challenge was overcome by combining functional magnetic resonance imaging (fMRI) and diffusion tensor imaging (DTI) in order to perform fMRI-guided accurate definition of appropriate seed areas for the DTI fiber tracking. In addition, the performance of the tasks was controlled by a MR-compatible power device.
  
  
  RESULTS
  Application of this combined approach to eight healthy volunteers and exemplary to three tumor patients showed that it is feasible to accurately reconstruct relevant fiber tracts belonging to a specific functional system.
  
  
  CONCLUSIONS
  fMRI-guided advanced DTI fiber tracking has the potential to provide accurate anatomical and functional information for a more informed therapeutic decision making.
authors.affiliation: Institute of Neuroradiology, University Hospital Zurich, Frauenklinikstrasse 10, 8091, Zürich, Switzerland. raimund.kleiser@gespag.at
authors.forename: Raimund
authors.initials: R
authors.lastname: Kleiser
authors.forename: Philipp
authors.initials: P
authors.lastname: Staempfli
authors.forename: Anton
authors.initials: A
authors.lastname: Valavanis
authors.forename: Peter
authors.initials: P
authors.lastname: Boesiger
authors.forename: Spyros
authors.initials: S
authors.lastname: Kollias
mesh_terms: D000465:Algorithms; D001921:Brain / Q000473:pathology* / Q000503:physiopathology*; D001932:Brain Neoplasms / Q000473:pathology* / Q000503:physiopathology*; D056324:Diffusion Tensor Imaging / Q000295:instrumentation / Q000379:methods*; D005240:Feasibility Studies; D007839:Functional Laterality; D005910:Glioma / Q000473:pathology / Q000503:physiopathology; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000295:instrumentation / Q000379:methods*; D008579:Meningioma / Q000473:pathology / Q000503:physiopathology; D009413:Nerve Fibers, Myelinated / Q000473:pathology / Q000502:physiology; D009434:Neural Pathways / Q000473:pathology / Q000503:physiopathology; D011597:Psychomotor Performance / Q000502:physiology