title: Multiple sclerosis: comparison of trace apparent diffusion coefficients with MR enhancement pattern of lesions.
abstract: OBJECTIVE
  Diffusion-weighted MR imaging and the trace apparent diffusion coefficient (ADC) provide important structural information about tissues. The purpose of this study was to investigate the relationship between trace ADC values and the enhancement pattern of multiple sclerosis (MS) lesions.
  
  
  METHODS
  Ninety-six lesions, identified in 24 patients with MS, were characterized by their enhancement pattern on contrast-enhanced T1-weighted MR images. There were 57 nonenhancing lesions (NELs), 28 homogeneously enhancing lesions (HELs), and 11 ring-enhancing lesions (RELs). The trace ADC means for each type of lesion and for normal-appearing white matter (NAWM) were calculated and compared using Student's t-test.
  
  
  RESULTS
  The mean trace ADC values for HELs (mean, 7.7 x 1(-10) m2s(-1); SD, 1.4 x 10(-10) m2s(-1)) were less than those for RELs (mean, 1.2 x 10(-9) m2s(-1); SD, 3.5 x 10(-10)m2s(-1)) and NELs (mean, 1.3 x 10(-9) m2(s-1); SD, 2.6 x 10(-10) m2(s-1)). There was a significant difference between the mean trace ADC values of HELs and RELs as well as between those for HELs and NELs. There was also a significant difference in the mean trace ADC values between all lesion types and NAWM (mean, 6.9 x 10(-10) m2s(-1); SD, 5.0 x 10(-11) m2s(-1)).
  
  
  CONCLUSIONS
  We found a predictable relationship between mean trace ADC and the pattern of enhancement in MS lesions, corresponding to reported histopathologic differences in myelination between lesion types and magnetization transfer ratios.
authors.affiliation: Department of Radiology, Hospital of the University of Pennsylvania, Philadelphia 19104, USA.
authors.forename: S
authors.initials: S
authors.lastname: Roychowdhury
authors.forename: J A
authors.initials: JA
authors.lastname: Maldjian
authors.forename: R I
authors.initials: RI
authors.lastname: Grossman
mesh_terms: D000328:Adult; D001921:Brain / Q000473:pathology; D003287:Contrast Media; D004058:Diffusion; D018450:Disease Progression; D005260:Female; D019786:Gadolinium DTPA; D006801:Humans; D007089:Image Enhancement; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000175:diagnosis*; D009186:Myelin Sheath / Q000473:pathology; D012680:Sensitivity and Specificity
chemical_list: D003287:Contrast Media; D019786:Gadolinium DTPA