title: Analysis of normal-appearing white matter of multiple sclerosis by tensor-based two-compartment model of water diffusion.
abstract: OBJECTIVE
  To compare the significance of the two-compartment model, considering diffusional anisotropy with conventional diffusion analyzing methods regarding the detection of occult changes in normal-appearing white matter (NAWM) of multiple sclerosis (MS).
  
  
  METHODS
  Diffusion-weighted images (nine b-values with six directions) were acquired from 12 healthy female volunteers (22-52 years old, median 33 years) and 13 female MS patients (24-48 years old, median 37 years). Diffusion parameters based on the two-compartment model of water diffusion considering diffusional anisotropy was calculated by a proposed method. Other parameters including diffusion tensor imaging and conventional apparent diffusion coefficient (ADC) were also obtained. They were compared statistically between the control and MS groups.
  
  
  RESULTS
  Diffusion of the slow diffusion compartment in the radial direction of neuron fibers was elevated in MS patients (0.121 × 10(-3) mm2/s) in comparison to control (0.100 × 10(-3) mm(2)/s), the difference being significant (P = 0.001). The difference between the groups was not significant in other comparisons, including conventional ADC and fractional anisotropy (FA) of diffusion tensor imaging.
  
  
  CONCLUSIONS
  The proposed method was applicable to clinically acceptable small data. The parameters obtained by this method improved the detectability of occult changes in NAWM compared to the conventional methods.
  
  
  CONCLUSIONS
  • Water diffusion was compared between the controls and multiple sclerosis patients. • A two-compartment model, considering diffusional anisotropy was selected for water diffusion analysis. • Axial and radial diffusion of fast and slow diffusion components were evaluated. • A new method was developed to obtain the metrics stably. • The metrics indicated high detectability of slight differences between the groups.
authors.affiliation: Research Center for Charged Particle Therapy, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba, 263-8555, Japan.
authors.forename: Yasuhiko
authors.initials: Y
authors.lastname: Tachibana
authors.forename: Takayuki
authors.initials: T
authors.lastname: Obata
authors.forename: Mariko
authors.initials: M
authors.lastname: Yoshida
authors.forename: Masaaki
authors.initials: M
authors.lastname: Hori
authors.forename: Koji
authors.initials: K
authors.lastname: Kamagata
authors.forename: Michimasa
authors.initials: M
authors.lastname: Suzuki
authors.forename: Issei
authors.initials: I
authors.lastname: Fukunaga
authors.forename: Kouhei
authors.initials: K
authors.lastname: Kamiya
authors.forename: Kazumasa
authors.initials: K
authors.lastname: Yokoyama
authors.forename: Nobutaka
authors.initials: N
authors.lastname: Hattori
authors.forename: Tomio
authors.initials: T
authors.lastname: Inoue
authors.forename: Shigeki
authors.initials: S
authors.lastname: Aoki
mesh_terms: D000328:Adult; D016880:Anisotropy; D001834:Body Water / Q000502:physiology; D016022:Case-Control Studies; D004058:Diffusion; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods; D056324:Diffusion Tensor Imaging / Q000379:methods; D005260:Female; D006801:Humans; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000473:pathology*; D009474:Neurons / Q000473:pathology; D066127:White Matter / Q000473:pathology*