A flared birdcage coil design for breast MRI at 0.35T

Magnetic resonance imaging takes an important part in breast cancer screening and has become the gold standard for clinical diagnosis. It has greatly facilitated the promotion of breast disease screening among a broad population of women with low cost and open space of low-field MR system. We proposed a new design of breast coil to improve the signal-to-noise ratio (SNR) of low-field breast MR images, which named a flared birdcage breast coil for its characteristics. Through deforming from the conventional cylindrical birdcage coil structure, our coil accommodates well human breast tissue while its inner horizontal radiofrequency field (B₁) is perfectly orthogonal to the vertical main field (B₀). The results of both electromagnetic field simulation and MR imaging experiments demonstrate excellent performance. Phantom imaging revealed significant SNR improvements of 50~60% in different planes compared to the commercial breast coil. Besides, we tried to load passive resonant rings to further improve the imaging quality and was confirmed.