According to some aspects, a portable magnetic resonance imaging system is provided, comprising a Bo magnet configured to produce a Bo magnetic field for an imaging region of the magnetic resonance imaging system, a noise reduction system configured to detect and suppress at least some electromagnetic noise in an operating environment of the portable magnetic resonance imaging system, and electromagnetic shielding provided to attenuate at least some of the electromagnetic noise in the operating environment of the portable magnetic resonance imaging system, the electromagnetic shielding arranged to shield a fraction of the imaging region of the portable magnetic resonance imaging system. According to some aspects, the electromagnetic shield comprises at least one electromagnetic shield structure adjustably coupled to the housing to provide electromagnetic shielding for the imaging region in an amount that can be varied. According to some aspects, substantially no shielding of the imaging region is provided.

A magnetic resonance coil and a magnetic resonance imaging system using the same are provided. The magnetic resonance coil may include an antenna, an amplifier, and a protective circuit. The antenna may be configured to receive a radio frequency (RF) signal emitted from an object. The antenna may not resonate with the RF signal. The amplifier operably coupled to the antenna configured to amplify the RF signal. The protective circuit may be configured to protect the antenna and the amplifier.

A device is for checking the authenticity of an areal data carrier having a zero-field nuclear magnetic resonance feature, having one or more excitation coils for producing excitation pulses for the zero-field NMR feature, an array of multiple receiver coils that are independent of the excitation coils and are at least partially arranged adjacent to each other for the spatially resolved detection of the signal response of the zero-field NMR feature, the number of receiver coils in the receiver coil array being greater than the number of excitation coils, and the area covered by the excitation coils at least partially covering the area covered by the receiver coils in the receiver coil array and exceeding the size of said area.

An apparatus (10) includes: a radiofrequency (RF) coil (18); a detune circuit (38) operatively coupled to the RF coil, wherein the detune circuit includes a decoupling inductor (40) configured as a transmitter (TX) inductor; and a harvester (44) coupled to the decoupling inductor for harvesting energy from the decoupling inductor.

A magnetic resonance imaging system (100, 300) for acquiring magnetic resonance data (142) from a subject (118) within an imaging zone (108) includes a magnetic resonance imaging antenna (113, 113′) comprising having multiple loop antenna elements (114, 114′) with multiple infrared thermometry sensors (115, 115′). The magnetic resonance imaging antenna is configured for being positioned adjacent to an external surface (119) of the subject and at least a portion of the multiple infrared thermometry sensors are directed towards the external surface. The magnetic resonance imaging system further includes a memory (134, 136) containing machine executable instructions (150, 152) and pulse sequence instructions (140). The machine executable instructions causes a processor controlling the system to: acquire (200) the magnetic resonance data by controlling the magnetic resonance imaging system with the pulse sequence instructions; repeatedly (202) measure at least one surface temperature (146) of the subject with the multiple infrared thermometry sensors during acquisition of the magnetic resonance data; and perform (204) a predefined action if the at least one surface temperature is above a predefined temperature.

A dual frequency coil package system for use in transmitting and receiving at least two frequencies in an MRI system, including a frequency converter coupled to the MRI system to receive a first frequency through the local transmit coil port and convert the first frequency to a second frequency, a second frequency transmit coil to receive the second frequency from the frequency converter and to transmit the second frequency, a dual tuned receiver coil to receive and to output the at least two frequencies, and a switchable receiver to receive the at least two frequencies output from the dual tuned receiver coil and to transmit the first frequency received from the dual tuned receiver coil directly to the MRI system, and to convert the second frequency received from the dual tuned receiver coil to the first frequency before transmission to the MRI system.

Various methods and systems are provided for a flexible, lightweight, low-cost radio frequency (RF) coil array of a magnetic resonance imaging (MRI) system. In one example, a posterior RF coil assembly for a MRI system includes an RF coil array including a plurality of RF coils and a deformable material housing the plurality of RF coils, each RF coil comprising a loop portion of distributed capacitance wire conductors and a coupling electronics unit coupled to each of the plurality of RF coils.

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.

A method for checking a detuning facility of an antenna coil of a magnetic resonance tomography unit, and a magnetic resonance tomography unit for carrying out the method are provided. In the method, a detuning facility of the antenna coil is activated. A first receive signal and a second receive signal are received. The first receive signal and the second receive signal are compared, and a warning signal is output depending on a result of the comparison.

A birdcage coil includes: (a) a pair of conductive end rings, each having a generally domed shape in axial cross section; (b) a plurality of conductive, elongated rungs extending between the pair of conductive end rings in an axial direction; and (c) an LC delay circuit incorporated into the pair of rings and the plurality of elongated rungs, where the LC delay circuit includes a plurality of capacitive elements and a plurality of inductive elements. In the present invention circumferential spacing between adjacent elongated rungs is varied to improve homogeneity of the volume excitation. Alternatively, or in addition, LC circuit capacitance and/or inductance values are varied to improve homogeneity of the volume excitation.