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.

A tunable 900 MHz transmit/receive volume coil was constructed for ¹H MR imaging of biological samples in a 21.1 T vertical bore magnet. To accommodate a diverse range of specimen and RF loads at such a high frequency, a sliding-ring adaptation of a low-pass birdcage was implemented through simultaneous alteration of distributed capacitance. To make efficient use of the constrained space inside the vertical bore, a modular probe design was implemented with a bottom-adjustable tuning and matching apparatus. The sliding ring coil displays good homogeneity and sufficient tuning range for different samples of various dimensions representing large span of RF loads. High resolution in vivo and ex vivo images of large rats (up to 350 g), mice and human postmortem tissues were obtained to demonstrate coil functionality and to provide examples of potential applications at 21.1 T.

[1]  Jullie W Pan,et al.  High frequency volume coils for clinical NMR imaging and spectroscopy , 1994, Magnetic resonance in medicine.

[2]  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.

[3]  R. Henkelman,et al.  Comparative SNR for high‐throughput mouse embryo MR microscopy , 2010, Magnetic resonance in medicine.

[4]  G. Randy Duensing,et al.  Common mode signal rejection methods for MRI: Reduction of cable shield currents for high static magnetic field systems , 2003 .

[5]  A. Briguet,et al.  A hybrid bird cage resonator for sodium observation at 4.7 T , 1992, Magnetic resonance in medicine.

[6]  D. Hoult.  Sensitivity and Power Deposition in a High‐Field Imaging Experiment , 2000, Journal of magnetic resonance imaging : JMRI.

[7]  P. Hof,et al.  A three-dimensional digital atlas database of the adult C57BL/6J mouse brain by magnetic resonance microscopy , 2005, Neuroscience.

[8]  Paul S. Tofts,et al.  Standing Waves in Uniform Water Phantoms , 1994 .

[9]  S Li,et al.  A birdcage coil tuned by RF shielding for application at 9.4 T. , 1998, Journal of magnetic resonance.

[10]  Christopher M Collins,et al.  BirdcageBuilder: Design of Specified-Geometry Birdcage Coils with Desired Current Pattern and Resonant Frequency. , 2002, Concepts in magnetic resonance.

[11]  K. Uğurbil,et al.  A microstrip transmission line volume coil for human head MR imaging at 4T. , 2003, Journal of magnetic resonance.

[12]  J. Tropp,et al.  Dissipation, resistance, and rational impedance matching for TEM and birdcage resonators , 2002 .

[13]  W. Wong,et al.  "Millipede" Imaging Coil Design for High Field Micro Imaging Applications , 2000 .

[14]  Richard L. Magin,et al.  High-Resolution Microcoil 1H-NMR for Mass-Limited, Nanoliter-Volume Samples , 1995, Science.

[15]  M. Murray,et al.  [Magnetic resonance imaging with 21.1 T and pathological correlations--diffuse Lewy body disease]. , 2011, Rinsho shinkeigaku = Clinical neurology.

[16]  G. Giribet,et al.  Application of magnetic resonance imaging in zoology , 2011, Zoomorphology.

[17]  Derek Seeber,et al.  Floating shield current suppression trap , 2004 .

[18]  K. Uğurbil,et al.  Analysis of wave behavior in lossy dielectric samples at high field , 2002, Magnetic resonance in medicine.

[19]  U. Bogdahn,et al.  High-resolution MR imaging of the rat spinal cord in vivo in a wide-bore magnet at 17.6 Tesla , 2004, Magnetic Resonance Materials in Physics, Biology and Medicine.

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

[21]  J. Shen,et al.  Integrated RF probe for in vivo multinuclear spectroscopy and functional imaging of rat brain using an 11.7 Tesla 89 mm bore vertical microimager , 2005, Magnetic Resonance Materials in Physics, Biology and Medicine.

[22]  Rudolf Stollberger,et al.  RF-field mapping in vivo , 1988 .

[23]  S. Su,et al.  A new miniaturizable birdcage resonator design with improved electric-field characteristics. , 1996, Journal of magnetic resonance. Series B.

[24]  J. Tropp.  The theory of the bird-cage resonator , 1989 .

[25]  J. Schenck,et al.  An efficient, highly homogeneous radiofrequency coil for whole-body NMR imaging at 1.5 T , 1985 .

[26]  K. A. Jenkins,et al.  Geometry comparisons of an 11‐T coaxial reentrant cavity (ReCav) coil , 2003 .

[27]  Mark C. Leifer,et al.  Resonant Modes of the Birdcage Coil , 1997 .

[28]  J. Pauly,et al.  Saturated double‐angle method for rapid B1+ mapping , 2006, Magnetic resonance in medicine.

[29]  T. M. Fitzgerald,et al.  Generalized electrical analysis of low-pass and high-pass birdcage resonators. , 1991, Magnetic resonance imaging.

[30]  Peter M. Jakob,et al.  Transmit‐receive coil‐arrays at 17.6T, configurations for 1H, 23Na, and 31P MRI , 2006 .

[31]  Peter M Jakob,et al.  Mouse MRI using phased‐array coils , 2007, NMR in biomedicine.