Simulation, design, and test of an elliptical surface coil for magnetic resonance imaging and spectroscopy

The simplest design of surface coils for magnetic resonance imaging (MRI) applications is circular and square loops, both producing a magnetic field perpendicular to the coil plane in the central region-of-interest (ROI), with an amplitude that decreases along the coil axis. However, a surface coil constituted by a loop with different geometry could be necessary when particular field-of-views (FOVs) are desired, especially for performing imaging in an elongated region. This can be achieved by using an elliptical loop, which can guarantee a wide longitudinal FOV and a good penetration in deep sample regions. This work proposes the application of a method for elliptical coil Signal-to-Noise Ratio (SNR) estimation previously developed for circular and square loop design, in which coil inductance and resistance are analytically calculated and the magnetic field pattern is estimated using the magnetostatic approach, while the sample-induced resistance is calculated with the vector potential calculation method. In the second part of the paper, we propose the simulation and the design of a transmit/receive elliptical coil for MRI in mice with a 3T clinical scanner. We also evaluated the coil performance in a preliminary magnetic resonance spectroscopy (MRS) study in phantom.