Original Research

MRI of late microstructural and metabolic alterations in radiation-induced brain injuries

  1. Kevin C. Chan BEng1,2,
  2. Pek-lan Khong MD3,
  3. Matthew M. Cheung BEng1,2,
  4. Silun Wang MPhil3,
  5. Ke-xia Cai PhD1,2,
  6. Ed X. Wu PhD1,2,*

Article first published online: 22 APR 2009

DOI: 10.1002/jmri.21736

Issue

Journal of Magnetic Resonance Imaging

Journal of Magnetic Resonance Imaging

Volume 29, Issue 5, pages 1013–1020, May 2009

Additional Information

How to Cite

Chan, K. C., Khong, P.-l., Cheung, M. M., Wang, S., Cai, K.-x. and Wu, E. X. (2009), MRI of late microstructural and metabolic alterations in radiation-induced brain injuries. J. Magn. Reson. Imaging, 29: 1013–1020. doi: 10.1002/jmri.21736

Author Information

  1. 1

    Laboratory of Biomedical Imaging and Signal Processing, The University of Hong Kong, Pokfulam, Hong Kong SAR, China

  2. 2

    Department of Electrical and Electronic Engineering, The University of Hong Kong, Pokfulam, Hong Kong SAR, China

  3. 3

    Department of Diagnostic Radiology, The University of Hong Kong, Pokfulam, Hong Kong SAR, China

*Laboratory of Biomedical Imaging and Signal Processing, Department of Electrical and Electronic Engineering, The University of Hong Kong, Hong Kong SAR, China

Publication History

  1. Issue published online: 22 APR 2009
  2. Article first published online: 22 APR 2009
  3. Manuscript Accepted: 9 JAN 2009
  4. Manuscript Received: 6 SEP 2008

Funded by

  • Hong Kong Research Grant Council. Grant Numbers: GRF HKU 7793/08M, GRF HKU 7587/06M
  • The University of Hong Kong CRCG grant

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Keywords:

  • diffusion tensor imaging;
  • proton magnetic resonance spectroscopy;
  • radiotherapy;
  • white matter;
  • neurotoxicity;
  • rat brain

Abstract

Purpose

To evaluate the late effects of radiation-induced damages in the rat brain by means of in vivo multiparametric MRI.

Materials and Methods

The right hemibrains of seven Sprague-Dawley rats were irradiated with a highly collimated 6 MV photon beam at a single dose of approximately 28 Gy. Diffusion tensor imaging (DTI), proton MR spectroscopy (1H-MRS), T2-weighted imaging, and T1-weighted imaging were performed to the same animals 12 months after radiation treatment.

Results

Compared with the contralateral side, a significantly higher percentage decrease in fractional anisotropy was observed in the ipsilateral fimbria of hippocampus (29%) than the external capsule (8%) in DTI, indicating the selective vulnerability of fimbria to radiation treatment. Furthermore, in 1H-MRS, significantly higher choline, glutamate, lactate, and taurine peaks by 24%, 25%, 87%, and 58%, respectively, were observed relative to creatine in the ipsilateral brain. Postmortem histology confirmed these white matter degradations as well as glial fibrillary acidic protein and glutamine synthetase immunoreactivity increase in the ipsilateral brain.

Conclusion

The microstructural and metabolic changes in late radiation-induced brain injuries were documented in vivo. These multiparametric MRI measurements may help understand the white matter changes and neurotoxicity upon radiation treatment in a single setting. J. Magn. Reson. Imaging 2009;29:1013–1020. © 2009 Wiley-Liss, Inc.

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