title: The use of multi b values diffusion-weighted imaging in patients with acute stroke.
abstract: BACKGROUND
  The purpose of this paper is to study the mechanism of apparent diffusion coefficient reduction after stroke by using multi b value diffusion-weighted imaging.
  
  
  METHODS
  Ten healthy people and 25 patients with acute stroke were enrolled. In healthy volunteers, region of interests were put in the semioval center and in the precentral gyrus. In patients with acute stroke, region of interests were put in lesions and contralateral normal brain regions. ADC(fast) and ADC(slow) are thought of as a fast and a slow apparent diffusion coefficient, which result from the extracellular and intracellular compartments, respectively. p (fast) and p (slow) are regarded as the percentage of signal intensities deriving from water diffusion of the extracellular and intracellular compartments, separately. All data were analyzed using paired, two-tailed t tests. Statistical analyses were performed using SPSS 15.0.
  
  
  RESULTS
  In patients with acute stroke, p (fast) in lesions (0.54 ± 0.11) is lower than that in normal regions (0.75 ± 0.09), while p (slow) is on the contrary. ADC(fast) and ADC(slow) values in lesions are less than those in normal areas. Compared with those in normal regions, p (fast) of lesions decreases by 28 %, and ADC(fast) and ADC(slow) of lesions went down by 27 and 36 %, respectively. There are statistically significant differences (P < 0.05) in ADC(fast), ADC(slow), and p (fast) between lesions and normal regions.
  
  
  CONCLUSIONS
  The increase in the volume of extracellular space and the decrease in ADC(slow) are the primary reasons that lead to the decrease in apparent diffusion coefficient of lesions after stroke.
authors: The Department of Magnetic Resonance Imaging, The Second Affiliated Hospital of Nanchang University, 1, Minde Road, Donghu District, Nanchang, China 330006.
authors: Zhenghua
authors: Z
authors: Liu
authors: Xinlan
authors: X
authors: Xiao
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D020521:Stroke / Q000473:pathology*