title: Peroxisomal biogenesis disorder: comparison of conventional MR imaging with diffusion-weighted and diffusion-tensor imaging findings.
abstract: OBJECTIVE
  Peroxisomal biogenesis disorders (PBDs) refer to a group of disorders of peroxisomal biogenesis causing neuronal migration disorder, delayed myelination, and demyelination. The aim of this study was to evaluate the added value of diffusion-weighted imaging (DWI) and diffusion tensor imaging (DTI) compared with that of conventional T2-weighted imaging in assessing the extent of white matter damage in patients with PBDs.
  
  
  METHODS
  Three patients (aged 12, 16, and 80 months) with PBD (type 1 protein targeting sequence [PTS1]) and three age-matched control subjects underwent MR imaging on a 1.5-T system. The protocol included axial T2-weighted, DWI, and DTI sequences. Fractional anisotropy (FA) and apparent diffusion coefficient (ADC) changes were calculated using regions of interest at several predefined white matter areas and compared with those of age-matched control subjects. Color-coded maps were obtained to visualize the range of FA values.
  
  
  RESULTS
  On the T2-weighted images, one patient revealed severe hypomyelination throughout the brain; the two other patients showed focal abnormal high-signal-intensity areas. All patients had significantly decreased FA values in white matter areas that appeared abnormal on the T2-weighted images. In two of the three patients, significant FA reduction was also found in normal-appearing white matter. The ADC values of the patients were significantly increased compared with those of the age-matched controls.
  
  
  CONCLUSIONS
  Although based on a small number of patients, our data suggest that DWI and DTI can be used to characterize and quantify white matter tract injury in patients with PBD-PTS1. Furthermore, our data suggest that these techniques have the potential to identify neurodegenerative changes not yet visible on T2-weighted images.
authors.affiliation: Department of Radiology, Academic Medical Center, Amsterdam, The Netherlands.
authors.forename: Birgitta S M
authors.initials: BS
authors.lastname: ter Rahe
authors.forename: Charles B L M
authors.initials: CB
authors.lastname: Majoie
authors.forename: Erik M
authors.initials: EM
authors.lastname: Akkerman
authors.forename: Gerard J
authors.initials: GJ
authors.lastname: den Heeten
authors.forename: Bwee T
authors.initials: BT
authors.lastname: Poll-The
authors.forename: Peter G
authors.initials: PG
authors.lastname: Barth
mesh_terms: D002648:Child; D005260:Female; D006801:Humans; D007223:Infant; D008279:Magnetic Resonance Imaging; D008297:Male; D018901:Peroxisomal Disorders / Q000175:diagnosis*