An Asymmetric Birdcage Coil Design for 19F Lung MR Imaging at 1.5 T

Magnetic resonance imaging (MRI) based on ¹⁹ F can detect the lung pulmonary ventilation status without radiation and lower cost, which has emerged as a promising approach in the post-COVID era. In this paper, we propose an asymmetric radio frequency (RF) birdcage coil uniquely tailored for ¹ H- ¹⁹ F lung MR imaging system. This newly designed coil can work nested into the ¹ H volume coil, thereby enabling simultaneous structural and functional imaging and enhancing patient comfort. After employing conformal mapping to obtain the transformed closed curve, ideal current distributions are directly assigned to finish capacitance calculations, enabling the asymmetric birdcage coil to yield a uniform RF field. The intensity and homogeneity of the produced field are validated by theoretic calculation and electromagnetic simulation. Upon those results, compared to the conventional circular birdcage coil, our novel coil design demonstrates superior performance, establishing its efficacy and superiority.