title: The effect of lacunar infarcts on white matter tract integrity.
abstract: OBJECTIVE
  Lacunar infarcts may cause disturbances of the white matter (WM) structure remote from the primary lesion. Here, we used diffusion MRI and tractography to (1) spatially characterize microstructural abnormalities along WM tracts containing a lacunar infarct and (2) relate abnormalities in remote parts of the affected WM tract to cognitive outcome.
  
  
  METHODS
  In 17 participants with a lacunar infarct, we reconstructed the affected WM tract using fiber tractography. The corresponding nonlesioned tract in the contralateral hemisphere served as a control tract. Diffusion parameters (fractional anisotropy and mean diffusivity) were plotted along the tract and related to measures of memory, executive functioning and information processing speed.
  
  
  RESULTS
  Diffusion abnormalities remote from the lacune were present in the affected tract compared with the control tract up to 2 cm from the lacune (9% to 17% decrease in fractional anisotropy, 11% to 27% increase in mean diffusivity; P<0.05). The severity of these abnormalities attenuated with increasing distance to the primary lesion. Furthermore, the degree of remote WM disturbances was related to worse cognitive functioning on all 3 domains, independent of the size of the lacune (r=0.6-0.8; P<0.05).
  
  
  CONCLUSIONS
  Lacunar infarcts are associated with abnormalities in the affected WM tract that extend centimeters beyond the lesion visible on conventional MRI. These secondary WM abnormalities may contribute to the cognitive deficits observed in patients with subcortical infarcts.
authors.affiliation: Department of Neurology, Rudolf Magnus Institute of Neuroscience, University Medical Center Utrecht, The Netherlands. yaelreijmer@gmail.com
authors.forename: Yael D
authors.initials: YD
authors.lastname: Reijmer
authors.forename: Whitney M
authors.initials: WM
authors.lastname: Freeze
authors.forename: Alexander
authors.initials: A
authors.lastname: Leemans
authors.forename: Geert Jan
authors.initials: GJ
authors.lastname: Biessels
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D016880:Anisotropy; D003072:Cognition Disorders / Q000209:etiology / Q000473:pathology / Q000503:physiopathology*; D056324:Diffusion Tensor Imaging / Q000295:instrumentation / Q000379:methods*; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D056784:Leukoencephalopathies / Q000209:etiology / Q000473:pathology / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D009412:Nerve Fibers / Q000502:physiology; D009434:Neural Pathways / Q000473:pathology / Q000503:physiopathology*; D009483:Neuropsychological Tests; D059409:Stroke, Lacunar / Q000150:complications / Q000473:pathology / Q000503:physiopathology*
keywords: brain MRI; cognition; diffusion tensor imaging; lacunar infarct