Journal of Neuro-Oncology

, Volume 112, Issue 1, pp 9–15 | Cite as

Radiation induced brain injury: assessment of white matter tracts in a pre-clinical animal model using diffusion tensor MR imaging

Laboratory Investigation


We aim to study radiation induced white matter injury in a pre-clinical model using Diffusion tensor MR imaging (DTI). Nineteen 12-week old Sprague–Dawley rats were irradiated to the right hemisphere using a linear accelerator. The dose distribution map was coregistered to the DTI map to generate the actual radiation dose to each white matter tract. Rats underwent longitudinal DTI scans at five time points from 4 to 48 weeks post-radiation with histological evaluations. Fractional anisotropy (FA) of the external capsule, fornix, cerebral peduncle, anterior commissure, optic tract and optic nerve was evaluated. Radiation dose was highest at the ipsilateral external capsule and fornix (29.4 ± 1.3 and 29.8 ± 1.1 Gy, respectively). Optic nerve received 50 % dose to the external capsule and other white matter tracts received 80 % dose. Significantly lower FA was firstly found in the ipsilateral external capsule at 4 weeks post-radiation and in the ipsilateral fornix at 40 weeks post-radiation compared to the contralateral side. Significantly lower FA was found in contralateral optic nerve compared to ipsilateral optic nerve at 48 weeks post-radiation despite ipsilateral optic nerves receiving higher radiation dose than contralateral optic nerve (p = 0.021). No differences were found in other white matter regions until 48 weeks. Histology indicated demyelination, axonal degeneration and coagulative necrosis in all injured white matter. DTI can serve as a promising tool for assessment of radiation induced white matter injury and regional radiosensitivity of white matter tracts.


DTI MRI Radiation Optic nerve Visual pathway 



Diffusion tensor MR imaging


Fractional anisotropy


Region of interest


Radiation induced optic neuropathy


Hematoxylin and eosin


Luxol fast blue


Neural filament



The study is supported by University of Hong Kong Committee on Research and Conference grants (HKU7587/06M).


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Copyright information

© Springer Science+Business Media New York 2013

Authors and Affiliations

  • Silun Wang
    • 1
  • Deqiang Qiu
    • 1
    • 2
  • Kwok-Fai So
    • 3
  • Ed X. Wu
    • 4
  • Lucullus H. T. Leung
    • 5
  • Jing Gu
    • 1
  • Pek-Lan Khong
    • 1
  1. 1.Department of Diagnostic RadiologyThe University of Hong KongHong KongHong Kong
  2. 2.Lucas Center for Imaging, Stanford UniversityStanfordUSA
  3. 3.Department of AnatomyThe University of Hong KongHong KongHong Kong
  4. 4.Laboratory of Biomedical Imaging and Signal ProcessingThe University of Hong KongHong KongHong Kong
  5. 5.Department of OncologyPrincess Margaret HospitalHong KongHong Kong

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