Coil Overview
I don't understand all the different types of coils in MR. Can you make sense of these?
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Representative cross-section of a superconducting scanner showing nested arrangement of "coils". Both superconducting and resistive shim coils are shown. Two different types of patient coils are also illustrated: a receive only spine coil array, and a transmit/receive knee coil.
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"An MR scanner is a coil within a coil within a coil within a coil . . . " I have always loved this simple description of an MR scanner. At its essence an MR scanner consists of multiple coils of wire, each serving a different purpose, stacked or nested like a set of Russian dolls. |
The relative coil positions can be appreciated in the diagram above, but it may also be useful to list them from outside in:
Main field (Bo) Coils (Principal magnet windings plus superconducting shim and shield coils)
→ Shim Coils (to improve homogeneity)
→ Gradient Coils (for imaging, including their active shields)
→ Radiofrequency (RF) Body Coil (transmits B1 field)
→ Patient coils (primarily to detect MR signal, some are transmit/receive)
Main field, shim, shield and gradient coils have been thoroughly discussed in previous questions. This segment of the web site deals with portions of the radiofrequency (RF) system -- coils responsible for perturbing the nuclear spin system and recording the NMR signal.
→ Shim Coils (to improve homogeneity)
→ Gradient Coils (for imaging, including their active shields)
→ Radiofrequency (RF) Body Coil (transmits B1 field)
→ Patient coils (primarily to detect MR signal, some are transmit/receive)
Main field, shim, shield and gradient coils have been thoroughly discussed in previous questions. This segment of the web site deals with portions of the radiofrequency (RF) system -- coils responsible for perturbing the nuclear spin system and recording the NMR signal.
References
GE Healthcare. MR Field Notes: RF Coils...They've come a long, long way. 2005.
Gruber B, Froeling M, Leiner T, Klomp DWJ. RF coils: a practical guide for nonphysicists. J Magn Reson Imaging 2018:48:590-604. (Comprehensive modern review)
GE Healthcare. MR Field Notes: RF Coils...They've come a long, long way. 2005.
Gruber B, Froeling M, Leiner T, Klomp DWJ. RF coils: a practical guide for nonphysicists. J Magn Reson Imaging 2018:48:590-604. (Comprehensive modern review)
Related Questions
What is the function(s) of radiofrequency (RF) coils?
What are gradient coils?
How do RF-transmit coils work?
What is the function(s) of radiofrequency (RF) coils?
What are gradient coils?
How do RF-transmit coils work?