title: Diffusion tensor imaging of white matter injury in a rat model of infantile hydrocephalus.
abstract: OBJECTIVE
  Diffusion tensor imaging (DTI) is a non-invasive MRI technique that has been used to quantify white matter (WM) abnormality in both clinical and experimental hydrocephalus (HCP). However, no DTI study has been conducted to characterize anisotropic diffusion properties in an animal model of infantile HCP. This DTI study was designed to investigate a rat model of HCP induced at postnatal day 21, a time developmentally equivalent to the human infancy.
  
  
  METHODS
  DTI data were acquired at approximately 4 weeks after the induction of HCP with kaolin injection. Using a 7 Tesla small animal MRI scanner we performed high-resolution DTI on 12 rats with HCP and 6 saline controls. Regions of interest (ROI) examined with quantitative comparisons include the genu, body, and splenium of the corpus callosum (gCC, bCC, and sCC, respectively), anterior, middle, and posterior external capsule (aEC, mEC, and pEC, respectively), internal capsule (IC), and fornix (FX). For each ROI, DTI metrics including fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (Dax), and radial diffusivity (Drad) were calculated.
  
  
  RESULTS
  We found that the anisotropic diffusion properties were abnormal across multiple WM regions in the brains of the HCP rats. Statistically significant differences included: (1) decreased FA and increased MD and Drad values in the gCC and bCC; (2) increased Dax in the sCC; (3) increased FA and Dax in the aEC; (4) increased FA in the mEC; (5) increased MD and Drad in the pEC; (6) increased FA and Dax in IC; (7) increased FA in FX.
  
  
  CONCLUSIONS
  These preliminary results provide the first evidence of WM injury quantified by DTI in a rat model of infantile HCP. Our data showed that DTI is a sensitive tool to characterize patterns of WM abnormalities and support the notion that WM impairment is region specific in response to HCP.
authors: Department of Radiology, Pediatric Neuroimaging Research Consortium, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 44529, USA.
authors: Weihong
authors: W
authors: Yuan
authors: James P
authors: JP
authors: McAllister
authors: Diana M
authors: DM
authors: Lindquist
authors: Nicholas
authors: N
authors: Gill
authors: Scott K
authors: SK
authors: Holland
authors: David
authors: D
authors: Henkel
authors: Akila
authors: A
authors: Rajagopal
authors: Francesco T
authors: FT
authors: Mangano
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D016880:Anisotropy; D001921:Brain / Q000473:pathology*; D056324:Diffusion Tensor Imaging; D004195:Disease Models, Animal; D006849:Hydrocephalus / Q000473:pathology*; D009413:Nerve Fibers, Myelinated / Q000473:pathology*; D051381:Rats; D017207:Rats, Sprague-Dawley