Using project-oriented RF coil design to optimise MR images
Chang-Hoon Choi, Ezequiel Farrher, Jörg Felder, Jing Wang, Antje Willuweit and N. Jon Shah
15th May 2023
Observing metabolic changes in the visual cortex using single-voxel MR spectroscopy (MRS) can provide valuable information relating to a number of eye-related diseases in vivo. However, the use of single-voxel MRS requires a target voxel that is sufficiently small to avoid interference from adjacent areas but large enough to maximise its signal-to-noise ratio (SNR). The choice of RF coils can considerably influence on the SNR. Thus, it is important to optimise the coil used for the measurements and this can contribute significantly to improving the SNR.
This work compared three different RF coils (circularly-polarised (CP) high-pass birdcage coil and two CP surface coils with different dimensions) and evaluated their performance in relation to the project-specific purpose of investigating metabolite concentration changes in the visual cortex of the in vivo rat brain, assessed by means of single-voxel MRS at 9.4 T.
The results demonstrated the clear benefits of the optimised small loop coil compared to the birdcage volume head coil and the medium-sized loop coil, leading the authors to conclude that although the default coil setting provided by manufacturers is advantageous when whole-brain or whole-head coverage is required, it could be limiting in certain studies that require more specific detail. Furthermore, by using an optimised setup, the entire measurement time can be reduced, and MR images or spectra can be acquired with much improved SNR or higher resolution. This also gives more precise measurements with minimum error and time to include additional, potentially interesting, sequences for multi-parametric studies or multiple voxel comparisons. Moreover, the shortened scan time supports animal welfare in translational studies.
Original publication: Project-Oriented RF Coil Comparison and Optimization for Preclinical, Single-Voxel MR Spectroscopy of the Rat Visual Cortex at 9.4 T