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4 T actively detunable transmit/receive transverse electromagnetic coil and 4‐channel receive‐only phased array for 1 H human brain studies
Author(s) -
Avdievich Nikolai I.,
Hetherington Hoby P.
Publication year - 2004
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.20264
Subject(s) - phased array , preamplifier , electromagnetic coil , physics , optics , radiofrequency coil , decoupling (probability) , acoustics , electromagnetic shielding , resonator , transmission line , human head , nuclear magnetic resonance , electrical engineering , materials science , engineering , optoelectronics , amplifier , cmos , control engineering , antenna (radio) , absorption (acoustics)
Abstract The design and construction of a 4 T transverse electromagnetic (TEM) transmit/receive head coil and a four‐channel phased array receive‐only RF system are described. To enable both high‐resolution imaging of the entire brain and high‐resolution spectroscopic imaging, active PIN diode decoupling was used in both the TEM resonator and each surface coil in the array. This configuration allows for both transmission and reception from the volume coil as well as reception from the phased array. The surface coils were decoupled by overlapping the coils and using preamplifier decoupling. Since at high frequencies construction of a lumped element matching quarter wavelength transformer, an important component of the preamplifier decoupling, becomes difficult, a transmission line approach was used. The system was tested and compared to a TEM volume transmit/receive head coil. A four‐ to sixfold improvement in signal‐to‐noise ratio from the sensitive volume of the array was achieved. Magn Reson Med 52:1459–1464, 2004. © 2004 Wiley‐Liss, Inc.