Premium
RF coils: A practical guide for nonphysicists
Author(s) -
Gruber Bernhard,
Froeling Martijn,
Leiner Tim,
Klomp Dennis W.J.
Publication year - 2018
Publication title -
journal of magnetic resonance imaging
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.563
H-Index - 160
eISSN - 1522-2586
pISSN - 1053-1807
DOI - 10.1002/jmri.26187
Subject(s) - radiofrequency coil , radio frequency , electromagnetic coil , rf power amplifier , magnetization , physics , magnetic field , nuclear magnetic resonance , sensitivity (control systems) , signal (programming language) , antenna (radio) , computer science , acoustics , electrical engineering , electronic engineering , telecommunications , amplifier , bandwidth (computing) , engineering , quantum mechanics , programming language
Radiofrequency (RF) coils are an essential MRI hardware component. They directly impact the spatial and temporal resolution, sensitivity, and uniformity in MRI. Advances in RF hardware have resulted in a variety of designs optimized for specific clinical applications. RF coils are the “antennas” of the MRI system and have two functions: first, to excite the magnetization by broadcasting the RF power (Tx‐Coil) and second to receive the signal from the excited spins (Rx‐Coil). Transmit RF Coils emit magnetic field pulses ( B 1 + ) to rotate the net magnetization away from its alignment with the main magnetic field (B 0 ), resulting in a transverse precessing magnetization. Due to the precession around the static main magnetic field, the magnetic flux in the receive RF Coil ( B 1 − ) changes, which generates a current I. This signal is “picked‐up” by an antenna and preamplified, usually mixed down to a lower frequency, digitized, and processed by a computer to finally reconstruct an image or a spectrum. Transmit and receive functionality can be combined in one RF Coil (Tx/Rx Coils). This review looks at the fundamental principles of an MRI RF coil from the perspective of clinicians and MR technicians and summarizes the current advances and developments in technology. Level of Evidence : 1 Technical Efficacy : Stage 6 J. Magn. Reson. Imaging 2018;48:590–604.