Optimization of a high sensitivity MRI receive coil for parallel human brain imaging

Two eight-channel MRI receive-only coils were developed to provide whole-brain coverage at 1.5 T and 3.0 T field strength, respectively. Objectives were an image signal-to-noise ratio superior to standard designs throughout the human brain, as well as high parallel imaging performance. Electromagnetic field simulations were used to determine array diameter and inter-element coil gap. Low mutual inductive coupling was achieved at 1.5 and 3.0 T using high-impedance pre-amplifiers. Coils show an average SNR improvement over commercial birdcage coils of 2.4 and 2.3 for the 1.5 T and 3.0 T design, respectively. The mean of the noise-amplification factor related to reconstruction of under-sampled data (g-factor) was 1.03 for 2-fold under-sampled data (rate-2) and 1.22 for rate-3 at 1.5 T. For data acquired with the 3.0 T coil array, these values were respectively 1.06 for rate-2 and 1.37 for rate-3.