Trajectory optimization of field of view within a Nonlinear Magnetic Field by a Single-sided Magnet for spatial encoding of portable MRI

Motivation: Single-sided MRI offers flexibility for the movements of the field-of-view (FoV) with respect to the magnet. This adds a degree-of-freedom for signal encoding especially when the gradients are non-linear. Goal(s): We aim to optimize the trajectory of the FoV within a non-linear magnet field, generated by a single-sided magnet array for good signal encoding. Approach: Genetic algorithm was used for the optimization. The fitness function includes the filling area of local k-spaces, an indicator of the encoding capability of non-linear gradient field. Results: The optimized trajectories result in improved signal encoding and thus improved image quality. Impact: This work provides an additional degree of freedom to encode signals using single-sided magnet/arrays besides the gradients of field patterns, to improve image quality. It extends the possibility to use a moving single-sided magnet/arrays for imaging.