On the Bending and Stretching of Liquid Metal Receive Coils for Magnetic Resonance Imaging

The eGaIn coil on neoprene demonstrated in this paper presents a stretchable radio frequency receive coil for magnetic resonance imaging (MRI). The coil with dimensions $\text{86 mm}\times \text{70 mm}$ is tuned to resonate at 128 MHz for 3 T MRI. We investigate the effect of stretching (up to 40% strain) and bending (50 mm radius of curvature) of the coil on the coil's resistance and resonance frequency. Measurements and simulations show a decrease in resonance frequency of 2.5 MHz per 10% strain. The higher resistivity of liquid metal compared to copper reduces the SNR of MRI scans by 34%; therefore, a tradeoff between flexibility and performance remains. Nevertheless, we have successfully performed MRI scans with the liquid metal coil.