title: DTI fiber tracking to differentiate demyelinating diseases from diffuse brain stem glioma.
abstract: OBJECTIVE
  Intrinsic diffuse brainstem tumors and demyelinating diseases primarily affecting the brainstem can share common clinical and radiological features, sometimes making the diagnosis difficult especially at the time of first clinical presentation. To explore the potential usefulness of new MRI sequences in particular diffusion tensor imaging fiber tracking in differentiating these two pathological entities, we review a series of brainstem tumors and demyelinating diseases treated at our institution.
  
  
  METHODS
  The clinical history including signs and symptoms and MRI findings of three consecutive demyelinating diseases involving the brainstem that presented with diagnostic uncertainty and three diffuse intrinsic brainstem tumors were reviewed, along with a child with a supratentorial tumor for comparison. Fiber tracking of the pyramidal tracts was performed for each patient using a DTI study at the time of presentation. Additionally Fractional Anisotropy values were calculated for each patient in the pons and the medulla oblongata.
  
  
  RESULTS
  Routine MR imaging was unhelpful in differentiating between intrinsic tumor and demyelination. In contrast, retrospective DTI fiber tracking clearly differentiated the pathology showing deflection of the pyramidal tracts posteriorly and laterally in the case of intrinsic brainstem tumors and, in the case of demyelinating disease, poorly represented and truncated fibers. Regionalized FA values were variable and of themselves were not predictive either pathology.
  
  
  CONCLUSIONS
  DTI fiber tracking of the pyramid tracts in patients with suspected intrinsic brainstem tumor or demyelinating disease presents two clearly different patterns that may help in differentiating between these two pathologies when conventional MRI and clinical data are inconclusive.
authors.affiliation: Department of Neurological Surgery, University of Washington School of Medicine, Seattle Children's Hospital, Seattle, WA 98105, USA.
authors.forename: Carlo
authors.initials: C
authors.lastname: Giussani
authors.forename: Andrew
authors.initials: A
authors.lastname: Poliakov
authors.forename: Raymond T
authors.initials: RT
authors.lastname: Ferri
authors.forename: Lauren L
authors.initials: LL
authors.lastname: Plawner
authors.forename: Samuel R
authors.initials: SR
authors.lastname: Browd
authors.forename: Dennis W W
authors.initials: DW
authors.lastname: Shaw
authors.forename: Tanya Z
authors.initials: TZ
authors.lastname: Filardi
authors.forename: Corrine
authors.initials: C
authors.lastname: Hoeppner
authors.forename: J Russell
authors.initials: JR
authors.lastname: Geyer
authors.forename: James M
authors.initials: JM
authors.lastname: Olson
authors.forename: James G
authors.initials: JG
authors.lastname: Douglas
authors.forename: Elisabeth H
authors.initials: EH
authors.lastname: Villavicencio
authors.forename: Richard G
authors.initials: RG
authors.lastname: Ellenbogen
authors.forename: Jeffrey G
authors.initials: JG
authors.lastname: Ojemann
mesh_terms: D000293:Adolescent; D001927:Brain Diseases / Q000175:diagnosis / Q000473:pathology*; D001933:Brain Stem / Q000473:pathology; D020295:Brain Stem Neoplasms / Q000175:diagnosis / Q000473:pathology*; D002648:Child; D002675:Child, Preschool; D003711:Demyelinating Diseases / Q000175:diagnosis / Q000473:pathology*; D003936:Diagnosis, Computer-Assisted / Q000379:methods*; D003937:Diagnosis, Differential; D056324:Diffusion Tensor Imaging / Q000379:methods*; D005260:Female; D005910:Glioma / Q000175:diagnosis / Q000473:pathology*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D011712:Pyramidal Tracts / Q000473:pathology; D012189:Retrospective Studies; D015173:Supratentorial Neoplasms / Q000175:diagnosis / Q000473:pathology; D055815:Young Adult