title: Microscopic disease in normal-appearing white matter on conventional MR images in patients with multiple sclerosis: assessment with magnetization-transfer measurements.
abstract: OBJECTIVE
  To assess for the presence of microscopic abnormalities in otherwise normal-appearing white matter on T2-weighted images in patients with multiple sclerosis (MS) by using magnetization-transfer (MT) measurements.
  
  
  METHODS
  Twenty-three patients with MS and nine healthy control subjects underwent magnetic resonance (MR) imaging with a 1.5-T system. MT ratios (MTRs) were measured in 16 areas of normal-appearing white matter identified on conventional T2-weighted images in patients with MS. MTRs in the same white-matter locations in control subjects were determined. The two groups were compared.
  
  
  RESULTS
  The mean whole-brain MTR of normal-appearing white matter in patients was 40.13% +/- 1.37 (standard deviation; range, 36.31%-42.09%); in control subjects, 42.93% +/- 0.95 (range, 41.62%-44.50%). The difference was statistically significant (P < or = .001). Except for the internal capsules, the difference in mean MTRs in each sublocation of the brain between patients and control subjects was statistically significant (P < or = .05).
  
  
  CONCLUSIONS
  MT measurements are more sensitive than conventional MR imaging in the detection of abnormalities beyond the resolution of T2-weighted imaging.
authors.affiliation: Department of Radiology, Hospital of the University of Pennsylvania, Philadelphia 19104-4283, USA.
authors.forename: L A
authors.initials: LA
authors.lastname: Loevner
authors.forename: R I
authors.initials: RI
authors.lastname: Grossman
authors.forename: J A
authors.initials: JA
authors.lastname: Cohen
authors.forename: F J
authors.initials: FJ
authors.lastname: Lexa
authors.forename: D
authors.initials: D
authors.lastname: Kessler
authors.forename: D L
authors.initials: DL
authors.lastname: Kolson
mesh_terms: D000328:Adult; D001921:Brain / Q000473:pathology*; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D009103:Multiple Sclerosis / Q000175:diagnosis*; D012680:Sensitivity and Specificity