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Neuroimaging assessment of memory‐related brain structures in a rat model of acute space‐like radiation
Author(s) -
Huang Lei,
Smith Anna,
Cummings Peter,
Kendall Edward J.,
Obenaus Andre
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.21661
Subject(s) - effective diffusion coefficient , magnetic resonance imaging , nuclear medicine , medicine , hippocampal formation , ex vivo , histopathology , radiosensitivity , diffusion mri , pathology , central nervous system , in vivo , neuroimaging , hippocampus , radiation therapy , radiology , biology , microbiology and biotechnology , psychiatry
Purpose To investigate the acute effects on the central nervous system (CNS) of 56 Fe radiation, a component of high‐energy charged particles (HZE) in space radiation, using quantitative magnetic resonance imaging (MRI) noninvasively. Materials and Methods Sprague–Dawley rats were exposed to whole‐brain 56 Fe (0, 1, 2, and 4 Gy). At 1 week postirradiation, MRI scans were made using T2‐weighted (T2WI), diffusion‐weighted (DWI), and contrast enhanced T1‐(CET1) imaging. T2 relaxation time and apparent diffusion coefficient (ADC) values were obtained from memory‐related brain regions of interest (ROIs). Histopathology was correlated using ex vivo tissues. Results No overt abnormalities were visualized using T2WI and DWI at 1 week postradiation. CET1 values did not differ significantly between the irradiated and control animals. Compared to 0 Gy, there were significant prolongations in T2 values and reductions in ADC after irradiation. In the absence of evident neuronal pathology, immunohistochemistry revealed astrocytic activation in 4 Gy animals. Conclusion At 1 week after whole‐brain 56 Fe exposure, T2 and ADC values can differentiate radiosensitivity in regions critical for hippocampal‐related memory. MRI may provide noninvasive assessment of the initial molecular/cellular disturbances in vivo after HZE irradiation. J. Magn. Reson. Imaging 2009;29:785–792. © 2009 Wiley‐Liss, Inc.