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Quantitative tissue sodium concentration mapping of normal rat brain
Author(s) -
Christensen James D.,
Barrère Bertrand J.,
Boada Fernando E.,
Vevea J. Michael,
Thulborn Keith R.
Publication year - 1996
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.1910360115
Subject(s) - calibration , brain tissue , sodium , signal (programming language) , nuclear magnetic resonance , chemistry , relaxation (psychology) , range (aeronautics) , in vivo , nuclear medicine , biomedical engineering , materials science , physics , computer science , medicine , microbiology and biotechnology , organic chemistry , quantum mechanics , composite material , biology , programming language
Abstract A quantitative in vivo method for obtaining maps of tissue sodium concentration (TSC) by MRI is compared to the invasive, global 22 Na radionuclide dilutional technique in the normal rat brain. The MR method uses a three‐dimensional projectional acquisition scheme to minimize signal losses from transverse relaxation. Internal calibration standards are used to convert the signal intensity into TSC after correction for B 1 inhomogeneities by using the ratio of 23 Na and 1 H images obtained with identical B 1 distributions and sensitivities at the two frequencies. Over the biological range of concentrations, the TSC, measured as the ratio of MR signals of 23 Na and 1 H, gives a linear response with concentration. In the normal rat brain, the mean TSC measured using the MRI method (TSC = 45 ± 4 m M , animals = 5) is not significantly different from the global 22 Na radionuclide method (TSC = 49 ± 6 m M , animals = 7).