Novel crusher coils for elimination of surface signals
Supervisor: Richard Bowtell
Description of project / Current research interests:
There are multiple applications of magnetic resonance imaging and spectroscopy for which it is useful to be able to attenuate the signal that arises from surface structures. These include 1H, 13C and 31P MR spectroscopy experiments where contaminating signal from superficial fat or skeletal muscle is problematic and experiments where attenuation of the strong signals arising near to surface RF coils is required [4-6]. Surface signal can be attenuated by using local coils which generate a spatially varying magnetic field that decays rapidly with distance from the surface. In previous work, crushing has been accomplished by using “meander-line” coils [1-4] in which the current flow is predominantly along one dimension. However, by exploiting insight into the spatial pattern of periodic field variation allowed by Maxwell’s equations, we can design novel crusher coils in which the current equally flows along two orthogonal directions. This yields crusher coils with some beneficial characteristics in comparison to previous implementations, including greater control of the field variation, less sensitivity to changes in relative orientation of the imaging and coil planes and potential to easily form arrays on a deformable curved surface, opening up the possibility of making wearable crusher coils.
This project will focus on a computational analysis of the optimal 2D crusher coil configurations on flat and curved surfaces. This will involve electromagnetic field calculations and simulations of the NMR signal evolution. It would the form the starting basis for a PhD project focusing on the development and experimental exploitation of the improved capabilities of 2D crusher coils.
References
1. Chen, W. and Ackerman J. , NMR in Biomedicine, 1990. 3(4): p. 147-57.
2. Boer, V.O., et al., Magnetic Resonance in Medicine, 2015. 73(6): p. 2062-2068.
3. Schaller, B., et al., Magnetic Resonance in Medicine, 2016. 75(3): p. 962-972.
4. Wiesler, D.G., et al. Journal of Magnetic Resonance Imaging, 1998. 8(4): p. 981-988