title: Analysis of normal-appearing white matter in multiple sclerosis: comparison of diffusion tensor MR imaging and magnetization transfer imaging.
abstract: OBJECTIVE
  Our purpose was to compare diffusion tensor MR and magnetization transfer imaging in assessing normal-appearing white matter (WM) regions in multiple sclerosis (MS).
  
  
  METHODS
  Diffusion tensor, magnetization transfer, and conventional MR imaging were performed in 12 patients with MS. Fractional anisotropy, apparent diffusion coefficients (ADCs), and magnetization transfer ratios (MTRs) were measured in plaques, normal-appearing periplaque WM (PWM) regions, and normal-appearing WM regions remote from plaques. Mean fractional anisotropy, ADCs, and MTRs were calculated and compared in WM regions.
  
  
  RESULTS
  Fractional anisotropy was lower in normal-appearing PWM regions than in remote WM regions (P <.001) but higher than in plaques (P <.001). MTRs were lower (not significantly, P =.19) in normal-appearing PWM regions than in remote regions. MTRs were higher in normal-appearing PWM regions than in plaques (P <.001). ADCs were higher in normal-appearing PWM regions than in remote regions (P =.008) but lower than in plaques (P =.001). Correlation between fractional anisotropy and MTRs of individual lesions was poor (r = 0.18) and between fractional anisotropy and ADC, modest (r = -0.39).
  
  
  CONCLUSIONS
  In MS, diffusion tensor MR imaging can depict differences between WM regions that are not apparent on conventional MR images. Anisotropy measurements may be more sensitive than those of MTRs in detecting subtle abnormalities in PWM.
authors.affiliation: Department of Radiology, Duke University Medical Center, Durham 27710, NC, USA.
authors.forename: A C
authors.initials: AC
authors.lastname: Guo
authors.forename: V L
authors.initials: VL
authors.lastname: Jewells
authors.forename: J M
authors.initials: JM
authors.lastname: Provenzale
mesh_terms: D000328:Adult; D016880:Anisotropy; D001921:Brain / Q000473:pathology*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D020529:Multiple Sclerosis, Relapsing-Remitting / Q000175:diagnosis* / Q000473:pathology; D012680:Sensitivity and Specificity