title: Defining and categorizing leukoencephalopathies of unknown origin: MR imaging approach.
abstract: OBJECTIVE
  To categorize leukoencephalopathies of unknown origin into a few major groups by using magnetic resonance (MR) imaging criteria to facilitate further studies, and to assess the possibility of defining "new" (i.e., until now unknown) disease entities within these major groups.
  
  
  METHODS
  MR images of 92 patients (55 male, 37 female; mean age, 9.3 years) with a leukoencephalopathy were examined by using a scoring list of 68 items. Seven major categories were defined according to the predominant location of the white matter abnormalities. Statistical analysis was used to assess the validity of these seven categories.
  
  
  RESULTS
  Statistical analysis results showed that the seven categories could be well distinguished by either using the defining variables initially accepted as inclusion criteria or selecting a few other variables found to have discriminating value. The additional variables confirmed that the categories are essentially distinct and vary systematically with regard to items other than the inclusion criteria. The existence of two recently defined leukoencephalopathies was confirmed, but no consistent evidence of other new disease entities could be provided.
  
  
  CONCLUSIONS
  Establishing these seven categories helps in the interpretation of individual studies by demonstrating features that the patient has in common with other patients, and it may facilitate further research on homogeneous subgroups of patients and allow pooling of data across multiple centers.
authors.affiliation: Department of Child Neurology, Free University Hospital, Amsterdam, The Netherlands. ms.vanderknaap@azvu.nl
authors.forename: M S
authors.initials: MS
authors.lastname: van der Knaap
authors.forename: S N
authors.initials: SN
authors.lastname: Breiter
authors.forename: S
authors.initials: S
authors.lastname: Naidu
authors.forename: A A
authors.initials: AA
authors.lastname: Hart
authors.forename: J
authors.initials: J
authors.lastname: Valk
mesh_terms: D001921:Brain / Q000473:pathology*; D001927:Brain Diseases / Q000145:classification / Q000175:diagnosis*; D002648:Child; D003711:Demyelinating Diseases / Q000175:diagnosis; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male