title: Tumor extension in high-grade gliomas assessed with diffusion magnetic resonance imaging: values and lesion-to-brain ratios of apparent diffusion coefficient and fractional anisotropy.
abstract: OBJECTIVE
  To determine whether the apparent diffusion coefficient (ADC) and fractional anisotropy (FA) can distinguish tumor-infiltrated edema in gliomas from pure edema in meningiomas and metastases.
  
  
  METHODS
  Thirty patients were studied: 18 WHO grade III or IV gliomas, 7 meningiomas, and 5 metastatic lesions. ADC and FA were determined from ROIs placed in peritumoral areas with T2-signal changes, adjacent normal appearing white matter (NAWM), and corresponding areas in the contralateral healthy brain. Values and lesion-to-brain ratios from gliomas were compared to those from meningiomas and metastases.
  
  
  RESULTS
  Values and lesion-to-brain ratios of ADC and FA in peritumoral areas with T2-signal changes did not differ between gliomas, meningiomas, and metastases (P = 0.40, P = 0.40, P = 0.61, P = 0.34). Values of ADC and FA and the lesion-to-brain ratio of FA in the adjacent NAWM did not differ between tumor types (P = 0.74, P = 0.25, and P = 0.31). The lesion-to-brain ratio of ADC in the adjacent NAWM was higher in gliomas than in meningiomas and metastases (P = 0.004), but overlapped between tumor types.
  
  
  CONCLUSIONS
  Values and lesion-to-brain ratios of ADC and FA in areas with T2-signal changes surrounding intracranial tumors and adjacent NAWM were not helpful for distinguishing pure edema from tumor-infiltrated edema when data from gliomas, meningiomas, and metastases were compared.
authors.affiliation: Department of Radiology, Lund University Hospital, Lund, Sweden. danielle.van_westen@med.lu.se
authors.forename: D
authors.initials: D
authors.lastname: van Westen
authors.forename: J
authors.initials: J
authors.lastname: Lätt
authors.forename: E
authors.initials: E
authors.lastname: Englund
authors.forename: S
authors.initials: S
authors.lastname: Brockstedt
authors.forename: E M
authors.initials: EM
authors.lastname: Larsson
mesh_terms: D000328:Adult; D000368:Aged; D016880:Anisotropy; D001929:Brain Edema / Q000209:etiology / Q000378:metabolism / Q000473:pathology*; D001932:Brain Neoplasms / Q000378:metabolism / Q000473:pathology* / Q000556:secondary; D003937:Diagnosis, Differential; D004058:Diffusion; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D005910:Glioma / Q000378:metabolism / Q000473:pathology*; D006801:Humans; D008297:Male; D008577:Meningeal Neoplasms / Q000378:metabolism / Q000473:pathology*; D008579:Meningioma / Q000378:metabolism / Q000473:pathology*; D008875:Middle Aged; D011446:Prospective Studies