Abstract: Systems and methods for generating a gradient waveform for use by a low-field MRI system to generate a gradient magnetic field are provided herein. The gradient waveform can be determined using first information indicative of the gradient waveform and second information indicative of hardware constraints of the low-field MRI system including a maximum voltage of the gradient power amplifier, a maximum slew rate of the gradient coil, a resistance of the gradient coil, and an inductance of the gradient coil. In some embodiments, the gradient waveform can be a trapezoidal gradient waveform determined to have a non-linear ramp-up portion and/or a non-linear ramp-down portion.

Abstract: A radio-frequency (RF) coil for use in a low-field magnetic resonance imaging system and methods of making the same are provided. The RF coil may include a conductor arranged on a substrate in an arrangement such that symmetry in the arrangement cancels at least a portion of a common mode voltage when a current is passed through the conductor. The RF coil may be included in a magnetic resonance imaging (MRI) system for imaging a patient having at least one B0 magnet for generating a B0 magnetic field.

Abstract: An apparatus for providing a B0 magnetic field for a magnetic resonance imaging system. The apparatus includes at least one permanent B0 magnet to contribute a magnetic field to the B0 magnetic field for the MRI system and a ferromagnetic frame configured to capture and direct at least some of the magnetic field generated by the B0 magnet. The ferromagnetic frame includes a first post having a first end and a second end, a first multi-pronged member coupled to the first end, and a second multi-pronged member coupled to the second end, wherein the first and second multi-pronged members support the at least one permanent B0 magnet.

Abstract: According to some aspects, a low-field magnetic resonance imaging system is provided. The low-field magnetic resonance imaging system comprises a magnetics system having a plurality of magnetics components configured to produce magnetic fields for performing magnetic resonance imaging, the magnetics system comprising, a B0 magnet configured to produce a B0 field for the magnetic resonance imaging system at a low-field strength of less than 0.

Abstract: Techniques for suppressing noise in an environment of a magnetic resonance (MR) imaging system having at least one primary coil and at least one auxiliary sensor. The techniques involve estimating a transform, that, when applied to noise received by the at least one auxiliary sensor, provides an estimate of noise received by the at least one primary coil. The transform is estimated from data obtained by the at least one primary coil and the least one auxiliary sensor, with the data being weighted prior to estimation to remove or suppress data in regions with a high signal to noise ratio. In turn, the estimated transform may be applied to noise measured by the at least one auxiliary sensor during imaging of a patient, to estimate and suppress noise present in the MR signals received by the at least one primary coil during imaging.

Abstract: Techniques of prospectively compensating for motion of a subject being imaged by an MRI system, the MRI system comprising a plurality of magnetics components including at least one gradient coil and at least one radio-frequency (RF) coil, the techniques comprising: obtaining first spatial frequency data and second spatial frequency data by operating the MRI system in accordance with a pulse sequence, wherein the pulse sequence is associated with a sampling path that includes at least two non-contiguous portions each for sampling a central region of k-space; determining a transformation using a first image obtained using the first spatial frequency data and a second image obtained using the second spatial frequency data; correcting the pulse sequence using the determined transformation to obtain a corrected pulse sequence; and obtaining additional spatial frequency data in accordance with the corrected pulse sequence.

Abstract: A method of operating a low-field magnetic resonance imaging (MRI) system, the method comprising: obtaining an initial set of k-space phase-encoding coordinates; generating a sampling path through at least some of the k-space phase-encoding coordinates in the initial set to mitigate impact of eddy currents on operation of the low-field MRI system; and operating the low-field MRI system using a pulse sequence in accordance with the sampling path to obtain spatial frequency data for generating one or more magnetic resonance (MR) images of a subject.

Abstract: Methods and apparatus for reducing noise in RF signal chain circuitry for a low-field magnetic resonance imaging system are provided. A switching circuit in the RF signal chain circuitry may include at least one field effect transistor (FET) configured to operate as an RF switch at an operating frequency of less than 10 MHz. A decoupling circuit may include tuning circuitry coupled across inputs of an amplifier and active feedback circuitry coupled between an output of the amplifier and an input of the amplifier, wherein the active feedback circuitry includes a feedback capacitor configured to reduce a quality factor of an RF coil coupled to the amplifier.

Abstract: A magnetic resonance (MR) imaging system, comprising a magnetics system having a plurality of magnetics components configured to produce magnetic fields for performing magnetic resonance imaging, and a sensor configured to detect electromagnetic interference conducted by a patient into an imaging region of the MR imaging system. The sensor may comprise at least one electrical conductor configured for electrically coupling to the patient. The MR imaging system may further comprise a noise reduction system configured to receive the electromagnetic interference from the sensor and to suppress electromagnetic interference in detected MR signals received by the MR imaging system based on the electromagnetic interference detected by the sensor.

Abstract: A magnetic resonance (MR) imaging system, comprising a magnetics system having a plurality of magnetics components configured to produce magnetic fields for performing magnetic resonance imaging, and a sensor configured to detect electromagnetic interference conducted by a patient into an imaging region of the MR imaging system. The sensor may comprise at least one electrical conductor configured for electrically coupling to the patient. The MR imaging system may further comprise a noise reduction system configured to receive the electromagnetic interference from the sensor and to suppress electromagnetic interference in detected MR signals received by the MR imaging system based on the electromagnetic interference detected by the sensor.

Abstract: A radio-frequency (RF) coil for use in a low-field magnetic resonance imaging system and methods of making the same are provided. The RF coil may include a substrate having a first and second side and a conductor. The conductor may include a first portion wound around the substrate from the first side to the second side at a first plurality of locations spaced between the first side and the second side and a second portion wound around the substrate from the second side to the first side at a second plurality of locations spaced between the first side and the second side, wherein the first plurality of locations alternate with the second plurality of locations spaced between the first side and the second side.

Abstract: Methods and apparatus for reducing noise in RF signal chain circuitry for a low-field magnetic resonance imaging system are provided. A switching circuit in the RF signal chain circuitry may include at least one field effect transistor (FET) configured to operate as an RF switch at an operating frequency of less than 10 MHz. A decoupling circuit may include tuning circuitry coupled across inputs of an amplifier and active feedback circuitry coupled between an output of the amplifier and an input of the amplifier, wherein the active feedback circuitry includes a feedback capacitor configured to reduce a quality factor of an RF coil coupled to the amplifier.

Abstract: Techniques for compensating for presence of eddy currents during the operation of a magnetic resonance imaging (MRI) system in accordance with a pulse sequence, the pulse sequence comprising a gradient waveform associated with a target gradient field. The techniques include: compensating for presence of eddy currents during operation of the MRI system at least in part by correcting the gradient waveform using a nonlinear function of a characteristic of the gradient waveform to obtain a corrected gradient waveform; and operating the MRI system in accordance with the corrected gradient waveform to generate the target gradient field.

Abstract: According to some aspects, a low-field magnetic resonance imaging system is provided. The low-field magnetic resonance imaging system comprises a magnetics system having a plurality of magnetics components configured to produce magnetic fields for performing magnetic resonance imaging, the magnetics system comprising, a B0 magnet, a plurality of gradient coils, and at least one radio frequency coil, a power system comprising one or more power components configured to provide power to the magnetics system to operate the magnetic resonance imaging system to perform image acquisition, and a power connection configured to connect to a single-phase outlet to receive mains electricity and deliver the mains electricity to the power system to provide power needed to operate the magnetic resonance imaging system.

Abstract: Methods and apparatus for reducing noise in RF signal chain circuitry for a low-field magnetic resonance imaging system are provided. A switching circuit in the RF signal chain circuitry may include at least one field effect transistor (FET) configured to operate as an RF switch at an operating frequency of less than 10 MHz. A decoupling circuit may include tuning circuitry coupled across inputs of an amplifier and active feedback circuitry coupled between an output of the amplifier and an input of the amplifier, wherein the active feedback circuitry includes a feedback capacitor configured to reduce a quality factor of an RF coil coupled to the amplifier.

Abstract: Methods and apparatus for reducing noise in RF signal chain circuitry for a low-field magnetic resonance imaging system are provided. A switching circuit in the RF signal chain circuitry may include at least one field effect transistor (FET) configured to operate as an RF switch at an operating frequency of less than 10 MHz. A decoupling circuit may include tuning circuitry coupled across inputs of an amplifier and active feedback circuitry coupled between an output of the amplifier and an input of the amplifier, wherein the active feedback circuitry includes a feedback capacitor configured to reduce a quality factor of an RF coil coupled to the amplifier.

Abstract: According to some aspects, a portable magnetic resonance imaging system is provided, comprising a magnetics system having a plurality of magnetics components configured to produce magnetic fields for performing magnetic resonance imaging. The magnetics system comprises a permanent B0 magnet configured to produce a B0 field for the magnetic resonance imaging system, and a plurality of gradient coils configured to, when operated, generate magnetic fields to provide spatial encoding of emitted magnetic resonance signals, a power system comprising one or more power components configured to provide power to the magnetics system to operate the magnetic resonance imaging system to perform image acquisition, and a base that supports the magnetics system and houses the power system, the base comprising at least one conveyance mechanism allowing the portable magnetic resonance imaging system to be transported to different locations.

Abstract: Techniques are described for controlling components of a Magnetic Resonance Imaging (MRI) system with a single controller, such as a Field Programmable Gate Array (FPGA), by dynamically instructing the controller to issue commands to the components using a processor coupled to the controller. According to some aspects, the controller may issue commands to the components of the MRI system whilst actively receiving commands from the processor to be later issued to the components.

Abstract: Techniques for generating magnetic resonance (MR) images of a subject from MR data obtained by a magnetic resonance imaging (MRI) system, the techniques include: obtaining input MR spatial frequency data obtained by imaging the subject using the MRI system; generating an MR image of the subject from the input MR spatial frequency data using a neural network model comprising: a pre-reconstruction neural network configured to process the input MR spatial frequency data; a reconstruction neural network configured to generate at least one initial image of the subject from output of the pre-reconstruction neural network; and a post-reconstruction neural network configured to generate the MR image of the subject from the at least one initial image of the subject.

Abstract: According to some aspects, a portable magnetic resonance imaging system is provided, comprising a magnetics system having a plurality of magnetics components configured to produce magnetic fields for performing magnetic resonance imaging. The magnetics system comprises a permanent B0 magnet configured to produce a B0 field for the magnetic resonance imaging system, and a plurality of gradient coils configured to, when operated, generate magnetic fields to provide spatial encoding of emitted magnetic resonance signals, a power system comprising one or more power components configured to provide power to the magnetics system to operate the magnetic resonance imaging system to perform image acquisition, and a base that supports the magnetics system and houses the power system, the base comprising at least one conveyance mechanism allowing the portable magnetic resonance imaging system to be transported to different locations.