39K and 23Na relaxation times and MRI of rat head at 21.1 T

At ultrahigh magnetic field strengths (B0 ≥ 7.0 T), potassium (39K) MRI might evolve into an interesting tool for biomedical research. However, 39K MRI is still challenging because of the low NMR sensitivity and short relaxation times. In this work, we demonstrated the feasibility of 39K MRI at 21.1 T, determined in vivo relaxation times of the rat head at 21.1 T, and compared 39K and sodium (23Na) relaxation times of model solutions containing different agarose gel concentrations at 7.0 and 21.1 T. 39K relaxation times were markedly shorter than those of 23Na. Compared with the lower field strength, 39K relaxation times were up to 1.9‐ (T1), 1.4‐ (T2S) and 1.9‐fold (T2L) longer at 21.1 T. The increase in the 23Na relaxation times was less pronounced (up to 1.2‐fold). Mono‐exponential fits of the 39K longitudinal relaxation time at 21.1 T revealed T1 = 14.2 ± 0.1 ms for the healthy rat head. The 39K transverse relaxation times were 1.8 ± 0.2 ms and 14.3 ± 0.3 ms for the short (T2S) and long (T2L) components, respectively. 23Na relaxation times were markedly longer (T1 = 41.6 ± 0.4 ms; T2S = 4.9 ± 0.2 ms; T2L = 33.2 ± 0.2 ms). 39K MRI of the healthy rat head could be performed with a nominal spatial resolution of 1 × 1 × 1 mm3 within an acquisition time of 75 min. The increase in the relaxation times with magnetic field strength is beneficial for 23Na and 39K MRI at ultrahigh magnetic field strength. Our results demonstrate that 39K MRI at 21.1 T enables acceptable image quality for preclinical research. Copyright © 2016 John Wiley & Sons, Ltd.

[1]  吉利 和.  腎皮質(Na++K+)activated ATPase (腎(特集)) , 1967 .

[2]  D. E. Goldman.  POTENTIAL, IMPEDANCE, AND RECTIFICATION IN MEMBRANES , 1943, The Journal of general physiology.

[3]  A. Hodgkin,et al.  The effect of sodium ions on the electrical activity of the giant axon of the squid , 1949, The Journal of physiology.

[4]  A. Grinnell,et al.  THE PHYSIOLOGY OF EXCITABLE CELLS , 1984 .

[5]  Bertrand Fontaine.  Periodic paralysis. , 2008, Advances in genetics.

[6]  Bernd Stoeckel,et al.  Sodium long‐component T  2* mapping in human brain at 7 Tesla , 2009, Magnetic resonance in medicine.

[7]  G. Bodenhausen,et al.  Multiple‐quantum NMR spectroscopy of S=3/2 spins in isotropic phase: A new probe for multiexponential relaxation , 1986 .

[8]  Ronald Ouwerkerk,et al.  Sodium MRI. , 2011, Methods in molecular biology.

[9]  R. D. Shannon.  Revised effective ionic radii and systematic studies of interatomic distances in halides and chalcogenides , 1976 .

[10]  Peter Bachert,et al.  Partial volume correction for in vivo 23Na-MRI data of the human brain , 2015, NeuroImage.

[11]  Oliver Kraff,et al.  MRI at 7 tesla and above: Demonstrated and potential capabilities , 2015, Journal of magnetic resonance imaging : JMRI.

[12]  Armin M Nagel,et al.  In vivo 39K MR imaging of human muscle and brain. , 2013, Radiology.

[13]  Keith R Thulborn,et al.  Feasibility of 39‐potassium MR imaging of a human brain at 9.4 Tesla , 2014, Magnetic resonance in medicine.

[14]  S. Grant,et al.  Initial in vivo rodent sodium and proton MR imaging at 21.1 T. , 2010, Magnetic resonance imaging.

[15]  W. Brey,et al.  In vivo chlorine and sodium MRI of rat brain at 21.1 T , 2014, Magnetic Resonance Materials in Physics, Biology and Medicine.

[16]  Costin Tanase,et al.  Loss of cell ion homeostasis and cell viability in the brain: what sodium MRI can tell us. , 2005, Current topics in developmental biology.

[17]  M. McKenna,et al.  Fatigue Mechanisms Determining Exercise Performance Muscle K , Na , and Cl disturbances and Na-K pump inactivation : implications for fatigue , 2008 .

[18]  R. Griggs,et al.  Periodic paralysis. , 2007, Handbook of clinical neurology.

[19]  Lothar R. Schad,et al.  First In Vivo Potassium-39 $(^{\bf 39}$K) MRI at 9.4 T Using Conventional Copper Radio Frequency Surface Coil Cooled to 77 K , 2014, IEEE Transactions on Biomedical Engineering.

[20]  Ravinder R. Regatte,et al.  A method for estimating intracellular sodium concentration and extracellular volume fraction in brain in vivo using sodium magnetic resonance imaging , 2014, Scientific Reports.

[21]  M. Weber,et al.  K+-dependent paradoxical membrane depolarization and Na+ overload, major and reversible contributors to weakness by ion channel leaks , 2009, Proceedings of the National Academy of Sciences.

[22]  Jens Frahm,et al.  W(h)ither human cardiac and body magnetic resonance at ultrahigh fields? technical advances, practical considerations, applications, and clinical opportunities , 2016, NMR in biomedicine.

[23]  Lothar R Schad,et al.  In vivo(39)K, (23)Na and (1)H MR imaging using a triple resonant RF coil setup. , 2009, Journal of magnetic resonance.

[24]  Wolfhard Semmler,et al.  3 Tesla Sodium Inversion Recovery Magnetic Resonance Imaging Allows for Improved Visualization of Intracellular Sodium Content Changes in Muscular Channelopathies , 2011, Investigative radiology.

[25]  Chunqi Qian,et al.  A volume birdcage coil with an adjustable sliding tuner ring for neuroimaging in high field vertical magnets: ex and in vivo applications at 21.1T. , 2012, Journal of magnetic resonance.

[26]  R. Brown,et al.  Potassium homeostasis and clinical implications. , 1984, The American journal of medicine.

[27]  Ravinder R Regatte,et al.  Sodium MRI: methods and applications. , 2014, Progress in nuclear magnetic resonance spectroscopy.

[28]  David Bradley,et al.  The Physiology of Excitable Cells, 4th edn. By DAVID J. AIDLEY. (Pp. xii+477; illustrated; £70/$95 hardback, £24.95/$47.95 paperback; ISBN 0 521 57415 3 hardback, 0 521 57421 8 paperback.) Cambridge: Cambridge University Press. 1998. , 1999 .

[29]  P. Lauterbur,et al.  The sensitivity of the zeugmatographic experiment involving human samples , 1979 .

[30]  Armin M Nagel,et al.  Hyperkalemic periodic paralysis and permanent weakness: 3-T MR imaging depicts intracellular 23Na overload--initial results. , 2012, Radiology.

[31]  F. Lehmann-Horn,et al.  Periodic paralysis: Understanding channelopathies , 2002, Current neurology and neuroscience reports.

[32]  R. Kim,et al.  Physiological basis for potassium (39K) magnetic resonance imaging of the heart. , 1999, Circulation research.

[33]  K R Thulborn,et al.  Comprehensive MR imaging protocol for stroke management: tissue sodium concentration as a measure of tissue viability in nonhuman primate studies and in clinical studies. , 1999, Radiology.

[34]  J. D. Robinson,et al.  The (Na+ + K+)-activated ATPase. Enzymatic and transport properties. , 1979, Biochimica et biophysica acta.

[35]  G. Somjen.  Mechanisms of spreading depression and hypoxic spreading depression-like depolarization. , 2001, Physiological reviews.

[36]  J. R. Long,et al.  Ultra-wide bore 900 MHz high-resolution NMR at the National High Magnetic Field Laboratory. , 2005, Journal of magnetic resonance.

[37]  D. Fieno,et al.  Theoretical basis for sodium and potassium MRI of the human heart at 1.5 T , 1997, Magnetic resonance in medicine.