title: Multi-parametric MR assessment of T(1) black holes in multiple sclerosis : evidence that myelin loss is not greater in hypointense versus isointense T(1) lesions.
abstract: BACKGROUND
  Chronic T(1) hypointense lesions in multiple sclerosis (MS) are areas of severe tissue destruction. The purpose of this study was to compare total water content (WC),myelin water content (MWC), magnetization transfer ratio (MTR), T(1) relaxation time (T(1)), mean T(2) relaxation time (GMT(2)) between stable MS lesions that are hypointense and isointense on T(1)-weighted images.
  
  
  METHODS
  Six MS patients were scanned five times over one year. WC, MWC, MTR, T(1) and GMT(2) were calculated for 15 isointense and 15 hypointense chronically stable T(1) lesions, as well as contralateral normal appearing white matter (NAWM).
  
  
  RESULTS
  All MR measurements from both iso- and hypointense stable lesion types were significantly different from NAWM. WC, T(1) and GMT(2) were significantly higher and MTR significantly lower in hypointense T(1) lesions compared to isointense lesions. MWC was not significantly different between iso- and hypointense lesions.
  
  
  CONCLUSIONS
  This work suggests that myelin loss occurs equally in both the chronic isointense and hypointense lesions but hypointense lesions are distinguished by increased extracellular water.
authors.affiliation: Dept. of Radiology, University of British Columbia, UBC Hospital, Vancouver, BC, V6T 2B5, Canada. lees@phas.ubc.ca
authors.forename: I M
authors.initials: IM
authors.lastname: Vavasour
authors.forename: D K B
authors.initials: DK
authors.lastname: Li
authors.forename: C
authors.initials: C
authors.lastname: Laule
authors.forename: A L
authors.initials: AL
authors.lastname: Traboulsee
authors.forename: G R W
authors.initials: GR
authors.lastname: Moore
authors.forename: A L
authors.initials: AL
authors.lastname: Mackay
mesh_terms: D000328:Adult; D001921:Brain / Q000473:pathology*; D001931:Brain Mapping; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000378:metabolism* / Q000473:pathology*; D009186:Myelin Sheath / Q000378:metabolism*; D012680:Sensitivity and Specificity; D014867:Water / Q000378:metabolism
chemical_list: D014867:Water