title: Apparent diffusion coefficient in vasogenic edema and reactive astrogliosis.
abstract: BACKGROUND
  Distinguishing between vasogenic edema and reactive astrogliosis may be difficult in some instances. This study was performed to test the hypothesis that diffusion-weighted (DW) imaging with apparent diffusion coefficient (ADC) maps can be used to differentiate these two types of changes.
  
  
  METHODS
  The study population included 11 patients with perilesional vasogenic edema and 11 patients with gliosis examined with conventional MR imaging and DW imaging. The signal intensities of conventional pulse sequences and ADC values were calculated in regions of interest placed in the hyperintense edematous or gliotic regions and compared with those of normal-appearing white matter. Signal intensity ratios and ADC values in gliosis were compared with those in vasogenic edema using the Mann-Whitney U-test.
  
  
  RESULTS
  While considerable overlap was present for signal intensity ratios on conventional MR images, areas of gliosis demonstrated significantly higher ADC values (1.76 +/- 0.09 x 10(-3) mm(2)/s) than areas of vasogenic edema (1.35 +/- 0.06 x 10(-3) mm(2)/s; P < 0.0001) without overlap.
  
  
  CONCLUSIONS
  ADC values are helpful in differentiating reactive gliosis from vasogenic edema.
authors: Radiology Center, Bahnhofstrasse 29, 86150, Augsburg, Germany. hagen@radiologie-augsburg.de
authors: Thomas
authors: T
authors: Hagen
authors: Frank
authors: F
authors: Ahlhelm
authors: Werner
authors: W
authors: Reiche
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001929:Brain Edema / Q000175:diagnosis* / Q000209:etiology / Q000473:pathology; D003287:Contrast Media; D003937:Diagnosis, Differential; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D019786:Gadolinium DTPA; D005911:Gliosis / Q000175:diagnosis* / Q000209:etiology / Q000473:pathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012815:Signal Processing, Computer-Assisted
chemical_list: D003287:Contrast Media; D019786:Gadolinium DTPA
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