title: Distant white-matter diffusion changes caused by tumor growth.
abstract: OBJECTIVE
  Various reports have suggested that the involvement of normal-looking white matter with tumors is not limited to just signal abnormalities detectable on conventional imaging. Thus, the purpose of this study was to investigate the distant effects of glioblastomas and metastases on white matter using diffusion tensor imaging (DTI).
  
  
  METHODS
  Data for 21 patients harboring a glioblastoma (n=12) or a metastasis (n=9) located at a distance of smaller or equal to 10mm from a DTI-based reconstruction of the pyramidal tract were analyzed, using regions of interest (ROIs) placed along the pyramidal tracts in the cerebral peduncle distant (>15 mm) from the tumor.
  
  
  RESULTS
  For the whole study population, fractional anisotropy (FA) was significantly lower on the side ipsilateral to the tumor (P<0.001), a difference that was also observed in the glioblastoma and metastasis subgroups. The trace value was significantly higher on the ipsilateral side in the whole population and metastasis subgroup, but not in the glioblastoma subgroup. The decrease in FA and the trace value increase were significant in a subgroup of patients with motor deficits, but not in those without such deficits.
  
  
  CONCLUSIONS
  Hemispheric glioblastomas and metastases located close to the pyramidal tract induce diffusion changes in the tract that are observable at a distance of greater than 15 mm from the tumor border in the absence of T2 signal changes. These changes are different in glioblastomas and metastases, and mechanisms other than Wallerian degeneration may be contributing to the observed changes.
authors: Department of Neurosurgery, J.E. Purkinje University, Masaryk Hospital, Socialni pece 12A, 401 00, Usti nad Labem, Czech Republic. amirzolal@gmail.com
authors: Amir
authors: A
authors: Zolal
authors: Ales
authors: A
authors: Hejcl
authors: Alberto
authors: A
authors: Malucelli
authors: Martina
authors: M
authors: Novakova
authors: Petr
authors: P
authors: Vachata
authors: Robert
authors: R
authors: Bartos
authors: Milous
authors: M
authors: Derner
authors: Martin
authors: M
authors: Sames
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001932:Brain Neoplasms / Q000473:pathology*; D056324:Diffusion Tensor Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009413:Nerve Fibers, Myelinated / Q000473:pathology*; D020361:Paraneoplastic Syndromes, Nervous System / Q000473:pathology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity