title: ADC mapping of normal human brain.
abstract: BACKGROUND
  The quantification of diffusion conditions in normal human brain has been gaining more and more attention since diffusion weighted imaging (DWI) was proved to be an important tool in the evaluation of cerebral pathologies, especially regarding the diagnosis of hyperacute stroke. The purpose of this study was to investigate the apparent diffusion coefficient (ADC) and anisotropy index (AI) in normal human brain to evaluate physiological ADC values for an ADC mapping of different brain regions.
  
  
  METHODS
  22 regions of interest (ROIs) in the ADC maps of 53 volunteers showing no cerebral pathologies were measured in the gray and white matter of the frontal, parietal and occipital lobes, the corpus callosum, and the lateral ventricles.
  
  
  RESULTS
  Apparent diffusion is quite inhomogeneous for different brain regions. In both subcortical white matter (ADC: 525 x 10(-8) mm2/s, AI: 0.05) and in gray matter (ADC: 1486 x 10(-8) mm2/s, AI: 0.05) diffusion was isotropic, while in periventricular white matter (ADC: 408 x 10(-8) mm2/s, AI: 0.34) and the corpus callosum (ADC: 799 x 10(-8) mm2/s, AI: 0.77) anisotropic.
  
  
  CONCLUSIONS
  With the exception of children and young adults, ADC seems to be intra- and interindividually constant, with no sex or age dependency for the patient sample we investigated (mean age: 62+/-9.4 years). Hence the measurement of ADC may provide an index of lesion severity.
authors.affiliation: Department of Neuroradiology, University of Saarland, Homburg, Germany. frah1@gmx.de
authors.forename: Frank
authors.initials: F
authors.lastname: Ahlhelm
authors.forename: Thomas
authors.initials: T
authors.lastname: Hagen
authors.forename: Guenther
authors.initials: G
authors.lastname: Schneider
authors.forename: Ulrich
authors.initials: U
authors.lastname: Dorenbeck
authors.forename: Abdullah
authors.initials: A
authors.lastname: Nabhan
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Reith
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016880:Anisotropy; D001921:Brain / Q000033:anatomy & histology* / Q000502:physiology; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged