Extended curvature birdcage coil design for localized magnetic field in 9.4 T MRI for multiple mouse imaging

Magnetic resonance imaging (MRI) for preclinical analysis is useful for testing medical procedures, therapies, and drug development. Preclinical MRI uses small animals, such as mice, for multiple studies. Preclinical studies are often needed to control target mouse models with different parameters; thus, performing simultaneous MRIs is desired to reduce study time and provide a fair comparison. In this study, we propose a variation of a birdcage coil that is capable of providing the same field intensity for each mouse compared to a traditional birdcage coil configuration. The arrangement of the proposed birdcage coil produces a uniform and strongly localized magnetic |B1|-field in each of the four target mice. The design involves rotating the legs of the birdcage coil so that the current distribution produces a uniform field inside each mouse. Electromagnetic simulations were performed to validate the proposed design. The proposed design exhibited a better field intensity than the reference linear, circularly polarized mode birdcage coils and an eight-channel loop array coil. The proposed customized birdcage coil arrangement promises a better field intensity and uniformity across multiple mouse imaging using 9.4 T preclinical MRI scanners.