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MRI of late microstructural and metabolic alterations in radiation‐induced brain injuries
Author(s) -
Chan Kevin C.,
Khong Peklan,
Cheung Matthew M.,
Wang Silun,
Cai Kexia,
Wu Ed X.
Publication year - 2009
Publication title -
journal of magnetic resonance imaging
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.563
H-Index - 160
eISSN - 1522-2586
pISSN - 1053-1807
DOI - 10.1002/jmri.21736
Subject(s) - white matter , fractional anisotropy , medicine , nuclear medicine , diffusion mri , creatine , in vivo , taurine , choline , in vivo magnetic resonance spectroscopy , pathology , magnetic resonance imaging , chemistry , radiology , biology , endocrinology , biochemistry , microbiology and biotechnology , amino acid
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 ( 1 H‐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 1 H‐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.