title: Elevated CNS average diffusion constant in Fabry disease.
abstract: OBJECTIVE
  Evaluation of the average brain diffusion constant in Fabry disease.
  
  
  BACKGROUND
  Fabry disease is an X-linked recessive lysosomal storage disorder secondary to deficiency of alpha-galactosidase A and resulting in excess tissue globotriaosylceramide, particularly in cerebral blood vessels. This has been associated with cerebral hyperperfusion. Increased tissue perfusion should increase interstitial water by the Starling relationship. This hypothesis was examined by measuring the average CNS diffusion constant (Dav) in patients with Fabry disease using diffusion-weighted magnetic resonance imaging (DWI).
  
  
  METHODS
  Axial DWI was performed at b=0 seconds/mm2 and b = 1000 seconds/mm2 (TR (pulse repetition time), 10000; TE (time to echo), 100; FOV (field of view), 22 cm: 3 mm interleaved slices; image matrix, 128 x 128; GE Signa, 1.5T). Eight healthy male volunteers (age range, 21-47 years) and 17 hemizygous patients with Fabry disease (age range, 19-49 years) were examined. Following DWI acquisition, the trace image and the diffusion distribution map were calculated. The diffusion distribution curve was then fitted by a multi-modal Gaussian curve, allowing estimation of Dav.
  
  
  RESULTS
  The Dav was 0.743 +/- 0.024 x 10(-5) cm2/second (mean +/- SD) for patients with Fabry disease and 0.726 +/- 0.014 x 10(-5) cm2/second for the control group. Dav was significantly increased in the patients with Fabry disease compared with the controls (p = 0.029)
  
  
  CONCLUSIONS
  The elevated Dav indicates increased brain tissue water diffusivity in patients with Fabry disease, a finding consistent with increased extracellular water and increased cerebral blood flow.
authors.affiliation: Developmental and Metabolic Neurology Branch, National Institute of Neurological Disorders and Stroke, Clinical Center, National Institutes of Health, Bethesda, MD 20892-1260, USA.
authors.forename: D F
authors.initials: DF
authors.lastname: Moore
authors.forename: R
authors.initials: R
authors.lastname: Schiffmann
authors.forename: A M
authors.initials: AM
authors.lastname: Ulug
mesh_terms: D000328:Adult; D001921:Brain / Q000473:pathology / Q000503:physiopathology*; D002560:Cerebrovascular Circulation / Q000502:physiology*; D002561:Cerebrovascular Disorders / Q000209:etiology* / Q000473:pathology / Q000503:physiopathology*; D004058:Diffusion; D038524:Diffusion Magnetic Resonance Imaging; D005110:Extracellular Space / Q000502:physiology*; D000795:Fabry Disease / Q000150:complications* / Q000473:pathology / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008432:Mathematical Computing; D008875:Middle Aged; D016011:Normal Distribution