The exemplary system and method facilitate excitation of RF magnetic fields in ultra-high field (UHF) magnetic resonance (MRI) systems (e.g., MRI/NMR system) using a slotted waveguide array (SWGA) as an exciter coil. The exemplary exciter coil, in some embodiments, is configurable to provide RF magnetic field B.sub.1.sup.+ with high field-uniformity, with high efficiency, with excellent circular polarization, with negligible axial z-component, with arbitrary large field of view, and with exceptional possibilities for field-optimizations via RF shimming.

An image processing apparatus according to an embodiment includes a processing circuitry. The processing circuitry is configured to acquires an image by capturing a subject laid on a table of a magnetic-resonance imaging apparatus with a camera, detects a loop having a possibility of generating an induced current by a magnetic field that is generated by the magnetic-resonance imaging apparatus from the image, and outputs a detection result.

An image processing apparatus according to an embodiment includes a processing circuitry. The processing circuitry is configured to acquires an image by capturing a subject laid on a table of a magnetic-resonance imaging apparatus with a camera, detects a loop having a possibility of generating an induced current by a magnetic field that is generated by the magnetic-resonance imaging apparatus from the image, and outputs a detection result.

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 passive apparatus including a plurality of resonators increases signal-to-noise ratio of radiofrequency signals emitted by a specimen and captured by an MRI machine. The apparatus increases the magnetic field component of radiofrequency energy during signal transmission from the MRI machine to the specimen, and/or reception of signals from the specimen to the MRI machine. Moreover, the apparatus enhances specimen safety by substantially avoiding unwanted generation of an electric field, or an increase in the electric field component of the RF energy. Use of the apparatus improves the images generated by the MRI machine, and/or reduces the time necessary for the MRI machine to capture the image.

A passive apparatus including a plurality of resonators increases signal-to-noise ratio of radiofrequency signals emitted by a specimen and captured by an MRI machine. The apparatus increases the magnetic field component of radiofrequency energy during signal transmission from the MRI machine to the specimen, and/or reception of signals from the specimen to the MRI machine. Moreover, the apparatus enhances specimen safety by substantially avoiding unwanted generation of an electric field, or an increase in the electric field component of the RF energy. Use of the apparatus improves the images generated by the MRI machine, and/or reduces the time necessary for the MRI machine to capture the image.

The exemplary system and method facilitate excitation of RF magnetic fields in ultra-high field (UHF) magnetic resonance (MRI) systems (e.g., MRI/NMR system) using a slotted waveguide array (SWGA) as an exciter coil. The exemplary exciter coil, in some embodiments, is configurable to provide RF magnetic field B.sub.1.sup.+ with high field-uniformity, with high efficiency, with excellent circular polarization, with negligible axial z-component, with arbitrary large field of view, and with exceptional possibilities for field-optimizations via RF shimming.

The exemplary system and method facilitate excitation of RF magnetic fields in ultra-high field (UHF) magnetic resonance (MRI) systems (e.g., MRI/NMR system) using a slotted waveguide array (SWGA) as an exciter coil. The exemplary exciter coil, in some embodiments, is configurable to provide RF magnetic field B.sub.1.sup.+ with high field-uniformity, with high efficiency, with excellent circular polarization, with negligible axial z-component, with arbitrary large field of view, and with exceptional possibilities for field-optimizations via RF shimming.

A multichannel array coil of an MRI apparatus achieves both a wide sensitivity and low noise. An RF coil (array coil) is provided with a plurality of subcoils. Each of those subcoils is adjusted to be receivable of nuclear magnetic resonance signals, and also adjusted so that a part of current (first current) passing through one subcoil upon receipt of the signals flows into the other subcoil in the form of sub-current. A flowing direction of the first current is opposite to the flowing direction of the sub-current, and an electric field generated by the first current within a subject and an electric field generated by the first sub-current within the subject intensify each other in the space between a first loop coil unit and a second loop coil unit. Accordingly, noise correlation that is determined by an inner product of the electric fields is reduced, thereby achieving low noise.

A multichannel array coil of an MRI apparatus achieves both a wide sensitivity and low noise. An RF coil (array coil) is provided with a plurality of subcoils. Each of those subcoils is adjusted to be receivable of nuclear magnetic resonance signals, and also adjusted so that a part of current (first current) passing through one subcoil upon receipt of the signals flows into the other subcoil in the form of sub-current. A flowing direction of the first current is opposite to the flowing direction of the sub-current, and an electric field generated by the first current within a subject and an electric field generated by the first sub-current within the subject intensify each other in the space between a first loop coil unit and a second loop coil unit. Accordingly, noise correlation that is determined by an inner product of the electric fields is reduced, thereby achieving low noise.