title: Diffusion tensor imaging reveals supplementary lesions to frontal white matter in idiopathic normal pressure hydrocephalus.
abstract: BACKGROUND
  Idiopathic normal-pressure hydrocephalus (INPH) is associated with white matter lesions, but the extent and severity of the lesions do not cohere with symptoms or improvement after shunting, implying the presence of further, yet undisclosed, injuries to white matter in INPH.
  
  
  OBJECTIVE
  To apply diffusion tensor imaging (DTI) to explore white matter lesions in patients with INPH before and after drainage of cerebrospinal fluid (CSF).
  
  
  METHODS
  Eighteen patients and 10 controls were included. DTI was performed in a 1.5T MRI scanner before and after 3-day drainage of 400 mL of CSF. Regions of interest included corpus callosum, capsula interna, frontal and lateral periventricular white matter, and centrum semiovale. White matter integrity was quantified by assessing fractional anisotropies (FA) and apparent diffusion coefficients (ADC), comparing them between patients and controls and between patients before and after drainage. The significance level corresponded to .05 (Bonferroni corrected).
  
  
  RESULTS
  Decreased FA in patients was found in 3 regions (P<.002, P<.001, and P<.001) in anterior frontal white matter, whereas elevated ADC was found in genu corpus callosum (P<.001) and areas of centrum semiovale associated with the precentral gyri (P<.002). Diffusion patterns in these areas did not change after drainage.
  
  
  CONCLUSIONS
  DTI reveals subtle injuries-interpreted as axonal loss and gliosis-to anterior frontal white matter where high-order motor systems between frontal cortex and basal ganglia travel, further supporting the notion that motor symptoms in INPH are caused by a chronic ischemia to the neuronal systems involved in the planning processes of movements.
authors.affiliation: Department of Clinical Neuroscience, Umeå University, Umeå, Sweden. niklas.lenfeldt@neuro.umu.se
authors.forename: Niklas
authors.initials: N
authors.lastname: Lenfeldt
authors.forename: Anne
authors.initials: A
authors.lastname: Larsson
authors.forename: Lars
authors.initials: L
authors.lastname: Nyberg
authors.forename: Richard
authors.initials: R
authors.lastname: Birgander
authors.forename: Anders
authors.initials: A
authors.lastname: Eklund
authors.forename: Jan
authors.initials: J
authors.lastname: Malm
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D016880:Anisotropy; D001921:Brain / Q000473:pathology*; D056324:Diffusion Tensor Imaging; D005260:Female; D006801:Humans; D006850:Hydrocephalus, Normal Pressure / Q000473:pathology*; D007090:Image Interpretation, Computer-Assisted; D008297:Male; D008875:Middle Aged