Development and Optimization of Surface and Volume Radiofrequency Coils Suitable for Fast-Field-Cycling Magnetic Resonance Imaging (FFC-MRI)

Abstract

Objective: To evaluate a modelling and design methodology employed in constructing and optimizing radiofrequency (RF) coils suitable for use with the whole-body fast-field-cycling Magnetic Resonance Imaging (FFC-MRI). It is also aimed at comparing the sensitivity and the signal-to-noise ratio (SNR) of the various types of surface RF coils constructed at the initial and final stages of this research.

Methodology: An experimental study carried out at Biomedical MRI Laboratory at University of Aberdeen. Various designs of RF coil were constructed, optimized and tested with network/signal analyser for use with an experimental FFC - MRI scanner, operating at a detection magnetic field of 0.2 T (proton Larmor frequency of 8.5 MHz). The coils comprised circular loop (CL) RF – receive surface coil and a birdcage RF – transmit volume coil.  The intrinsic parameters of the CL coils were measured using a search-coil field probe and a network/signal analyser.

Results: The CL surface coil constructed with copper wire had resonant frequency of 8.46 MHz and Quality factor (Q – factor) of 47.1 while the resonant frequency of the one constructed with litz wire was 8.54 MHz and Q - factor of 85.4 MHz. The intrinsic parameter of the birdcage volume coil was 8.48 MHz and Q - factor of 102.

Conclusion: Bench testing of the coils showed promise as receiver and transmit coils for the FFC-MRI system