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Inhomogeneous sodium accumulation in the ischemic core in rat focal cerebral ischemia by 23 Na MRI
Author(s) -
Yushmanov Victor E.,
Kharlamov Alexander,
Yanovski Boris,
LaVerde George,
Boada Fernando E.,
Jones Stephen C.
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.21816
Subject(s) - ischemia , effective diffusion coefficient , middle cerebral artery , homogeneous , cerebral cortex , core (optical fiber) , cortex (anatomy) , medicine , lesion , chemistry , magnetic resonance imaging , nuclear magnetic resonance , nuclear medicine , pathology , biology , physics , radiology , neuroscience , optics , thermodynamics
Purpose To test the hypotheses that (i) the regional heterogeneity of brain sodium concentration ([Na + ] br ) provides a parameter for ischemic progression not available from apparent diffusion coefficient (ADC) data, and (ii) [Na + ] br increases more in ischemic cortex than in the caudate putamen (CP) with its lesser collateral circulation after middle cerebral artery occlusion in the rat. Materials and Methods 23 Na twisted projection MRI was performed at 3 Tesla. [Na + ] br was independently determined by flame photometry. The ischemic core was localized by ADC, by microtubule‐associated protein‐2 immunohistochemistry, and by changes in surface reflectivity. Results Within the ischemic core, the ADC ratio relative to the contralateral tissue was homogeneous (0.63 ± 0.07), whereas the rate of [Na + ] br increase (slope) was heterogeneous ( P < 0.005): 22 ± 4%/h in the sites of maximum slope versus 14 ± 1%/h elsewhere (here 100% is [Na + ] br in the contralateral brain). Maximum slopes in the cortex were higher than in CP ( P < 0.05). In the ischemic regions, there was no slope/ADC correlation between animals and within the same brain ( P > 0.1). Maximum slope was located at the periphery of ischemic core in 8/10 animals. Conclusion Unlike ADC, 23 Na MRI detected within‐core ischemic lesion heterogeneity. J. Magn. Reson. Imaging 2009;30:18–24. © 2009 Wiley‐Liss, Inc.