title: Measuring Brain Tissue Integrity during 4 Years Using Diffusion Tensor Imaging.
abstract: DTI is an MR imaging measure of brain tissue integrity. Little is known regarding the long-term longitudinal evolution of lesional and nonlesional tissue DTI parameters in multiple sclerosis and the present study examines DTI evolution over 4 years.
  
  
  
  Twenty-one patients with multiple sclerosis were imaged for up to 48 months after starting natalizumab therapy. Gadolinium-enhancing lesions at baseline, chronic T2 lesions, and normal-appearing white matter were followed longitudinally. T2 lesions were subclassified as black holes and non-black holes. Within each ROI, the average values of DTI metrics were derived by using Analysis of Functional Neuro Images software. The longitudinal trend in DTI metrics was estimated by using a mixed-model regression analysis.
  
  
  
  A significant increase was observed for axial diffusivity (P < .001) in gadolinium-enhancing lesions and chronic T2 lesions during 4 years. No significant change in radial diffusivity either in normal-appearing white matter or lesional tissue was observed. The evolution of axial diffusivity was different in gadolinium-enhancing lesions (P < .001) and chronic T2 lesions (P = .02) compared with normal-appearing white matter.
  
  
  
  An increase in axial diffusion in both gadolinium-enhancing lesions and T2 lesions may relate to the complex evolution of chronically demyelinated brain tissue. Pathologic changes in normal-appearing white matter are likely more subtle than in lesional tissue and may explain the stability of these measures with DTI.
authors.affiliation: From the Department of Neurology (D.O., R.J.F.), Neurological Institute, Mellen Center for Multiple Sclerosis Treatment and Research ontaned@ccf.org.
authors.forename: D
authors.identifier: 0000-0002-2838-9148
authors.initials: D
authors.lastname: Ontaneda
authors.affiliation: Imaging Institute (K.S., J.L., M.J.L., M.D.P.).
authors.forename: K
authors.identifier: 0000-0002-5633-4494
authors.initials: K
authors.lastname: Sakaie
authors.affiliation: Imaging Institute (K.S., J.L., M.J.L., M.D.P.).
authors.forename: J
authors.identifier: 0000-0002-3574-6035
authors.initials: J
authors.lastname: Lin
authors.affiliation: Department of Quantitative Health Sciences (X.-F.W.), Cleveland Clinic Foundation, Cleveland, Ohio.
authors.forename: X-F
authors.identifier: 0000-0001-8212-6931
authors.initials: XF
authors.lastname: Wang
authors.affiliation: Imaging Institute (K.S., J.L., M.J.L., M.D.P.).
authors.forename: M J
authors.identifier: 0000-0002-7022-8436
authors.initials: MJ
authors.lastname: Lowe
authors.affiliation: Imaging Institute (K.S., J.L., M.J.L., M.D.P.).
authors.forename: M D
authors.identifier: 0000-0002-4715-5718
authors.initials: MD
authors.lastname: Phillips
authors.affiliation: From the Department of Neurology (D.O., R.J.F.), Neurological Institute, Mellen Center for Multiple Sclerosis Treatment and Research.
authors.forename: R J
authors.identifier: 0000-0002-4263-3717
authors.initials: RJ
authors.lastname: Fox
mesh_terms: D000328:Adult; D001921:Brain / Q000000981:diagnostic imaging* / Q000473:pathology*; D056324:Diffusion Tensor Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000000981:diagnostic imaging* / Q000473:pathology*; D066127:White Matter / Q000000981:diagnostic imaging / Q000473:pathology