title: The role of diffusion-weighted imaging in patients with brain tumors.
abstract: OBJECTIVE
  Diffusion-weighted images (DWIs) have been used to study various diseases, particularly since echo-planar techniques shorten examination time. Our hypothesis was that DWIs and tumor apparent diffusion coefficients (ADCs) could provide additional useful information in the diagnosis of patients with brain tumors.
  
  
  METHODS
  Using a 1.5-T MR unit, we examined 56 patients with histologically verified or clinically diagnosed brain tumors (17 gliomas, 21 metastatic tumors, and 18 meningiomas). We determined ADC values and signal intensities on DWIs both in the solid portion of the tumor and in the peritumoral, hyperintense areas on T2-weighted images. We also evaluated the correlation between ADC values and tumor cellularity in both gliomas and meningiomas.
  
  
  RESULTS
  The ADCs of low-grade (grade II) astrocytomas were significantly higher (P =.0004) than those of other tumors. Among astrocytic tumors, ADCs were higher in grade II astrocytomas (1.14 +/- 0.18) than in glioblastomas (0.82 +/- 0.13). ADCs and DWIs were not useful in determining the presence of peritumoral neoplastic cell infiltration. The ADC values correlated with tumor cellularity for both astrocytic tumors (r = -.77) and meningiomas (r = -.67).
  
  
  CONCLUSIONS
  The ADC may predict the degree of malignancy of astrocytic tumors, although there is some overlap between ADCs of grade II astrocytomas and glioblastomas.
authors: Department of Radiology, Izumi Municipal Hospital, Izumi-shi , Osaka, Japan.
authors: K
authors: K
authors: Kono
authors: Y
authors: Y
authors: Inoue
authors: K
authors: K
authors: Nakayama
authors: M
authors: M
authors: Shakudo
authors: M
authors: M
authors: Morino
authors: K
authors: K
authors: Ohata
authors: K
authors: K
authors: Wakasa
authors: R
authors: R
authors: Yamada
mesh_terms: D000328:Adult; D000368:Aged; D001254:Astrocytoma / Q000175:diagnosis; D001921:Brain / Q000473:pathology; D001932:Brain Neoplasms / Q000175:diagnosis* / Q000556:secondary; D004058:Diffusion; D005260:Female; D005909:Glioblastoma / Q000175:diagnosis; D005910:Glioma / Q000175:diagnosis*; D006801:Humans; D007089:Image Enhancement; D008279:Magnetic Resonance Imaging; D008297:Male; D008577:Meningeal Neoplasms / Q000175:diagnosis*; D008579:Meningioma / Q000175:diagnosis*; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D012680:Sensitivity and Specificity