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 B.sub.0 magnet configured to produce a B.sub.0 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. According to some aspects, the base has a maximum horizontal dimension of less than or equal to approximately 50 inches. According to some aspects, the portable magnetic resonance imaging system weighs less than 1,500 pounds. According to some aspects, the portable magnetic resonance imaging system has a 5-Gauss line that has a maximum dimension of less than or equal to five feet.

Certain aspects of the present disclosure provide methods and apparatus for performing electron paramagnetic resonance (EPR) spectroscopy on a fluid from a flowing well, such as fluid from hydrocarbon recovery operations flowing in a downhole tubular, wellhead, or pipeline. One example method generally includes, for a first EPR iteration, performing a first frequency sweep of discrete electromagnetic frequencies on a cavity containing the fluid; determining first parameter values of reflected signals from the first frequency sweep; selecting a first discrete frequency corresponding to one of the first parameter values that is less than a threshold value; activating a first electromagnetic field in the fluid at the first discrete frequency; and while the first electromagnetic field is activated, performing a first DC magnetic field sweep to generate a first EPR spectrum.

A magnetic resonance imaging apparatus according to an embodiment includes a static magnetic field generator, a transmit/receive system, and an acquiring means. The static magnetic field generator is configured to apply a second static magnetic field in addition to a first static magnetic field serving as a reference. The transmit/receive system is configured to perform transmitting and receiving at a single frequency. The processing circuitry is configured to acquire a magnetic resonance signal by employing the transmit/receive system. The transmit/receive system is configured to perform transmitting and receiving at a resonance frequency of a hydrogen nucleus in a state in which the first static magnetic field is applied and is configured to perform transmitting and receiving at a resonance frequency of a nuclide different from the hydrogen nucleus in a state in which the second static magnetic field is applied in addition to the first static magnetic field.

Systems and methods for obtaining simultaneous X-ray—magnetic resonance imaging (MRI) images are provided. A magnetic resonance X-ray CT (MRX) system can combine X-ray imaging and MRI in a cost-effective and relatively simple solution for improved imaging. During imaging of a subject, the X-ray source and X-ray detector can be simultaneously rotated around the subject, and the means for generating a magnetic field can also be rotated around the subject. The means for generating a magnetic field can be a plurality of permanent magnets.

Systems and methods for obtaining simultaneous X-ray—magnetic resonance imaging (MRI) images are provided. A magnetic resonance X-ray CT (MRX) system can combine X-ray imaging and MRI in a cost-effective and relatively simple solution for improved imaging. During imaging of a subject, the X-ray source and X-ray detector can be simultaneously rotated around the subject, and the means for generating a magnetic field can also be rotated around the subject. The means for generating a magnetic field can be a plurality of permanent magnets.

Apparatuses, methods, and computer program products for reducing an appearance of an artifact in an image generated by a magnetic resonance imaging (MRI) system are disclosed. The apparatus includes a magnetic field generating device configured to create an inhomogeneity in the magnetic field of an MRI system and prevent at least one out-of-field excitation during imaging.

Apparatuses, methods, and computer program products for reducing an appearance of an artifact in an image generated by a magnetic resonance imaging (MRI) system are disclosed. The apparatus includes a magnetic field generating device configured to create an inhomogeneity in the magnetic field of an MRI system and prevent at least one out-of-field excitation during imaging.

A method of producing a permanent magnet shim configured to improve a profile of a B.sub.0 magnetic field produced by a B.sub.0 magnet is provided. The method comprises determining deviation of the B.sub.0 magnetic field from a desired B.sub.0 magnetic field, determining a magnetic pattern that, when applied to magnetic material, produces a corrective magnetic field that corrects for at least some of the determined deviation, and applying the magnetic pattern to the magnetic material to produce the permanent magnet shim. According to some aspects, a permanent magnet shim for improving a profile of a B.sub.0 magnetic field produced by a B.sub.0 magnet is provided. The permanent magnet shim comprises magnetic material having a predetermined magnetic pattern applied thereto that produces a corrective magnetic field to improve the profile of the B.sub.0 magnetic field.

A method of producing a permanent magnet shim configured to improve a profile of a B.sub.0 magnetic field produced by a B.sub.0 magnet is provided. The method comprises determining deviation of the B.sub.0 magnetic field from a desired B.sub.0 magnetic field, determining a magnetic pattern that, when applied to magnetic material, produces a corrective magnetic field that corrects for at least some of the determined deviation, and applying the magnetic pattern to the magnetic material to produce the permanent magnet shim. According to some aspects, a permanent magnet shim for improving a profile of a B.sub.0 magnetic field produced by a B.sub.0 magnet is provided. The permanent magnet shim comprises magnetic material having a predetermined magnetic pattern applied thereto that produces a corrective magnetic field to improve the profile of the B.sub.0 magnetic field.

A method for performing magnetic resonance imaging is provided. The method includes providing a magnetic resonance imaging system comprising: a radio frequency receive system comprising a radio frequency receive coil, and a housing, wherein the housing comprises a permanent magnet for providing an inhomogeneous permanent gradient field, a radio frequency transmit system, and a single-sided gradient coil set. The method also includes placing the receive coil proximate a target subject; applying a sequence of chirped pulses via the transmit system; applying a multi-slice excitation along the inhomogeneous permanent gradient field; applying a plurality of gradient pulses via the gradient coil set orthogonal to the inhomogeneous permanent gradient field; acquiring a signal of the target subject via the receive system, wherein the signal comprises at least two chirped pulses; and forming a magnetic resonance image of the target subject.