Abstract: The present disclosure provides systems and methods for removing electromagnetic interference from low-field magnetic resonance images. In one aspect, a method can include projecting a low-field strength magnetic field toward an object of interest located within a field of view and transmitting a radio frequency pulse sequence to a radio frequency coil assembly configured to selectively excite magnetization in the object of interest within the field of view. The method can further include receiving an output signal from the radio frequency coil assembly during a signal acquisition period and receiving a sample signal from the radio frequency coil assembly during an interference period. The method can further include comparing the output signal and the sample signal to identify an interference component and adjusting the output signal based on the interference component.

Abstract: The present disclosure provides various devices, systems, and methods for active shimming for an MRI system. For example, an MRI system can a first gradient coil, a second gradient coil, a third gradient coil, and a permanent magnet. The permanent magnet is configured to generate a magnetic field B0 having a low field strength. A method for active shimming the MRI system can include a set of candidate shimming configurations with first current values associated with the first gradient coil, second current values associated with the second gradient coil, and third current values associated with the third gradient coil. The method further includes applying, for each candidate shimming configuration, a pulse sequence; acquiring, for each pulse sequence, a magnetic resonance (MR) signal; determining, for each MR signal, a signal bandwidth based on a frequency domain of the MR signal; and designating a shimming configuration for the MRI system.

Abstract: The present disclosure provides various devices, systems, and methods for iterative shimming in magnetic resonance imaging (MRI). In one aspect, a method of iterative shimming can include generating a field map of a magnetic field B0 from an MRI system. The MRI system can include a shim tray and an array of permanent magnets to generate the magnetic field B0. The shim tray can include slots to receive shim magnets. The method can further include shimming the MRI system by iteratively: applying the field map to a genetic algorithm to determine a set of slots to receive a set of shim magnets, installing the set of shim magnets in the set of slots, generating a next field map of the magnetic field B0, and either performing a next iteration based on the next field map or determining to not perform the next iteration based on the next field map.

Abstract: The present disclosure provides various systems and methods for magnetic resonance imaging. In one aspect, a method for magnetic resonance imaging can include receiving k-space data sets acquired by radiofrequency (RF) coils. Each of the k-space data sets can correspond to a different one of the RF coils. Each of the k-space data sets can be truncated and/or under sampled. The method can further include generating partial images of a field of view based on the k-space data sets and generating an initial image based on the partial images. The initial image can be full image of the field of view. The method can further include applying an iterative image reconstruction technique to generate an updated image based on the initial image.

Abstract: The present disclosure provides systems and methods for removing electromagnetic interference from low-field magnetic resonance images. In one aspect, a method can include projecting a low-field strength magnetic field toward an object of interest located within a field of view and transmitting a radio frequency pulse sequence to a radio frequency coil assembly configured to selectively excite magnetization in the object of interest within the field of view. The method can further include receiving an output signal from the radio frequency coil assembly during a signal acquisition period and receiving a sample signal from the radio frequency coil assembly during an interference period. The method can further include comparing the output signal and the sample signal to identify an interference component and adjusting the output signal based on the interference component.