Advanced Quadratic RF Phase Selective Encoding through Nutation and Fingerprinting (qRF-SENF) for Gradient-Free Quantitative Imaging

Motivation: Eliminate the need for B0 gradients and improve the efficiency of quantitative imaging. Goal(s): To develop an advanced approach for gradient-free quantitative imaging called Quadratic RF Phase Selective Encoding through Nutation and Fingerprinting (qRF-SENF). Approach: Design an improved sequence for qRF-SENF that increases sensitivities to off-resonance and relaxation parameters. Validate the advanced approach with a 1D experiment. Evaluate the SNR efficiency of the approach in simulation. Results: Successfully validated an improved sequence for qRF-SENF with a 1D experiment that differentiates between two materials. Simulations of SNR efficiency show the advanced approach has sufficient SNR for current and future experiments. Impact: Selective Encoding through Nutation and Fingerprinting (SENF) is a gradient-free quantitative imaging technique that simultaneously encodes spatial and quantitative information with the potential to be implemented on low-cost MRI scanners with flexible magnet design and acquisition strategies.