Sodium mapping in focal cerebral ischemia in the rat by quantitative 23Na MRI |
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| Authors: | Victor E. Yushmanov PhD Boris Yanovski MD Alexander Kharlamov MD PhD George LaVerde MD PhD Fernando E. Boada PhD Stephen C. Jones PhD |
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| Affiliation: | 1. Department of Anesthesiology, Allegheny‐Singer Research Institute, Pittsburgh, Pennsylvania;2. MR Research Center, Department of Radiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania;3. Department of Neurology, Allegheny‐Singer Research Institute, Pittsburgh, Pennsylvania |
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| Abstract: | Purpose To validate 23Na twisted projection magnetic resonance imaging (MRI) as a quantitative technique to assess local brain sodium concentration ([Na+]br) during rat focal ischemia every 5.3 minutes. Materials and Methods The MRI protocol included an ultrashort echo‐time (0.4 msec), a correction of radiofrequency (RF) inhomogeneities by B1 mapping, and the use of 0–154 mM NaCl calibration standards. To compare MRI [Na+]br values with those obtained by emission flame photometry in precision‐punched brain samples of about 0.5 mm3 size, MR images were aligned with a histological three‐dimensional reconstruction of the punched brain and regions of interest (ROIs) were placed precisely over the punch voids. Results The Bland–Altman analysis of [Na+]br in normal and ischemic cortex and caudate putamen of seven rats quantitated by 23Na MRI and flame photometry yielded a mean bias and limits of agreement (at ±1.96 SD) of 2% and 43% of average, respectively. A linear increase in [Na+]br was observed between 1 and 6 hours after middle cerebral artery occlusion. Conclusion 23Na MRI provides accurate and reliable results within the whole range of [Na+]br in ischemia with a temporal resolution of 5.3 minutes and precisely targeted submicroliter ROIs in selected brain structures. J. Magn. Reson. Imaging 2009;29:962–966. © 2009 Wiley‐Liss, Inc. |
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| Keywords: | rat brain focal ischemia tissue sodium 23Na MRI |
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