A flexible nested sodium and proton coil array with wideband matching for knee cartilage MRI at 3T.
We describe a 2 × 6 channel sodium/proton array for knee MRI at 3T. Multielement coil arrays are desirable because of well-known signal-to-noise ratio advantages over volume and single-element coils. However, low tissue-coil coupling that is characteristic of coils operating at low frequency can make the potential gains from a phased array difficult to realize.



The issue of low tissue-coil coupling in the developed six-channel sodium receive array was addressed by implementing 1) a mechanically flexible former to minimize the coil-to-tissue distance and reduce the overall diameter of the array and 2) a wideband matching scheme that counteracts preamplifier noise degradation caused by coil coupling and a high-quality factor. The sodium array was complemented with a nested proton array to enable standard MRI.



The wideband matching scheme and tight-fitting mechanical design contributed to >30% central signal-to-noise ratio gain on the sodium module over a mononuclear sodium birdcage coil, and the performance of the proton module was sufficient for clinical imaging.



We expect the strategies presented in this study to be generally relevant in high-density receive arrays, particularly in x-nuclei or small animal applications. Magn Reson Med 76:1325-1334, 2016. © 2015 Wiley Periodicals, Inc.
Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, New York, USA. ryan.brown@nyumc.org.|Center for Advanced Imaging Innovation and Research, Department of Radiology, New York University School of Medicine, New York, New York, USA. ryan.brown@nyumc.org.|NYU WIRELESS, Polytechnic Institute of New York University, Brooklyn, New York, USA. ryan.brown@nyumc.org.
Ryan
R
Brown
Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, New York, USA.|Center for Advanced Imaging Innovation and Research, Department of Radiology, New York University School of Medicine, New York, New York, USA.
Karthik
K
Lakshmanan
Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, New York, USA.|Center for Advanced Imaging Innovation and Research, Department of Radiology, New York University School of Medicine, New York, New York, USA.
Guillaume
G
Madelin
Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, New York, USA.|Center for Advanced Imaging Innovation and Research, Department of Radiology, New York University School of Medicine, New York, New York, USA.|NYU WIRELESS, Polytechnic Institute of New York University, Brooklyn, New York, USA.
Leeor
L
Alon
Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, New York, USA.|Center for Advanced Imaging Innovation and Research, Department of Radiology, New York University School of Medicine, New York, New York, USA.
Gregory
G
Chang
Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, New York, USA.|Center for Advanced Imaging Innovation and Research, Department of Radiology, New York University School of Medicine, New York, New York, USA.|NYU WIRELESS, Polytechnic Institute of New York University, Brooklyn, New York, USA.
Daniel K
DK
Sodickson
Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, New York, USA.|Center for Advanced Imaging Innovation and Research, Department of Radiology, New York University School of Medicine, New York, New York, USA.
Ravinder R
RR
Regatte
Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, New York, USA.|Center for Advanced Imaging Innovation and Research, Department of Radiology, New York University School of Medicine, New York, New York, USA.
Graham C
GC
Wiggins
D015415:Biomarkers / Q000378:metabolism; D002358:Cartilage, Articular / Q000033:anatomy & histology / Q000378:metabolism*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006025:Glycosaminoglycans / Q000378:metabolism*; D006801:Humans; D007719:Knee Joint / Q000033:anatomy & histology / Q000378:metabolism*; D008279:Magnetic Resonance Imaging / Q000295:instrumentation* / Q000379:methods; D057054:Molecular Imaging / Q000295:instrumentation*; D066244:Proton Magnetic Resonance Spectroscopy / Q000295:instrumentation*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012975:Sodium Isotopes / Q000493:pharmacokinetics*; D014159:Transducers
D015415:Biomarkers; D006025:Glycosaminoglycans; D012975:Sodium Isotopes
FLORET; coupling; dual-tuned; phased-array; preamplifier noise