Nuclear spins are excited in a region of interest in an object under examination by a radio-frequency pulse. During at least one phase of the radio-frequency pulse, excitation fields are transmitted while magnetic field gradients are simultaneously applied so that the magnetization of the nuclear spins moves on a trajectory through a transmission k-space. In a first phase of the at least one phase of the radio-frequency pulse, the trajectory moves at a radial distance around the center of the transmission k-space. The radial distance corresponds to the radius of a sphere superimposed with at least one radial harmonic.

A method and apparatus are provided for limiting a B1 field used for magnetic resonance imaging (MRI). The techniques described herein reduce a waste of performance of the B1 field while ensuring patient safety and improving the MR imaging quality.

A magnetic resonance tomography scanner with a noise suppressor for suppressing interferences of reception and a method for operation of the magnetic resonance tomography scanner are provided. The noise suppressor receives an interference signal with a sensor, determines a noise suppression signal with a noise suppression controller, and sends the noise suppression signal using a controllable radio frequency amplifier via a transmit antenna, so that the interference signal on a receive antenna of the magnetic resonance tomography scanner is reduced.

Some radio-frequency coils comprise three or more electrical conductors that form a radio-frequency coil element. Each of the three or more electrical conductors extends along at least a respective part of a length of the radio-frequency coil element, and, along the length of the radio-frequency coil element, the three or more electrical conductors are separated from each other by respective distances and by one or more dielectric materials.

Various methods and systems are provided for correcting transmit attenuation of an amplifier of a transmit radio frequency (RF) coil for use in a magnetic resonance imaging (MRI) system. In one example, a method includes setting a reference value of transmit attenuation for an amplifier of a transmit radio frequency (RF) coil, acquiring a two-dimensional B.sub.1 field map with the transmit attenuation set at the reference value, determining a mean flip angle from the B.sub.1 field map, determining a transmit attenuation correction value based on a prescribed flip angle and the mean flip angle, correcting the reference value of transmit attenuation with the transmit attenuation correction value to obtain a final value of transmit attenuation, and performing an MRI scan with the transmit attenuation set at the value.

A system is described for emitting a radiofrequency field for a magnetic resonance imaging device, including a volumetric antenna that emits a radiofrequency field, a device for homogenizing the radiofrequency field arranged between said volume antenna and a part of the body to be imaged. The device may include a first continuous metal track with an overall length of approximately 0.5 to approximately 1.5 times said wavelength of the radio frequency field. The first metallic track may occupy a surface with a largest dimension ranging between approximately 5% and approximately 15% of said wavelength of the radio frequency field. The first metal track is arranged in a pattern including a plane of symmetry that is normal to the electrical component of the radio frequency field, so as to give the device an electric dipole property including a natural frequency strictly greater than the frequency of the radio frequency field.

A magnetic resonance imaging system (100) comprising a main magnet (104) for generating a main magnetic field within an imaging zone (108); a radio frequency, RF, antenna (114), comprising an RF input terminal (300) and an RF output terminal (302); an RF system for supplying radio-frequency power to the RF input terminal (300) to energize the antenna (114), the antenna (114) being further adapted for picking up magnetic resonance signals (144) from the imaging zone (108); a data acquisition system (126) for receiving the magnetic resonance signals (144) from the RF output terminal (302); wherein the RF input terminal (300) is in galvanic connection to the antenna (114) and the RF output terminal (302) is inductively coupled to the antenna (114).

A method and device for radio-frequency field inhomogeneity correction in magnetic resonance imaging. The method includes: obtaining a first MR image by scanning a target tissue using a first pulse sequence; obtaining a B.sub.1.sup.+ field map of the target tissue; obtaining a B.sub.1.sup.−: field map of the target tissue based on the first MR image and the B.sub.1.sup.+ field map; and performing B1 field inhomogeneity correction on a second MR image of the target tissue based on the B.sub.1.sup.+ field map and the B.sub.1.sup.− field map, where the second MR image is an MR image obtained after scanning of the target tissue using any imaging protocol and any pulse sequence.

In one embodiment, a receiving coil includes at least one coil element that can simultaneously receive a plurality of magnetic resonance signals having different frequencies, wherein a resonance structure for the different frequencies is provided in a single plane in each of the at least one coil element.

Some radio-frequency coils comprise three or more electrical conductors that form a radio-frequency coil element. Each of the three or more electrical conductors extends along at least a respective part of a length of the radio-frequency coil element, and, along the length of the radio-frequency coil element, the three or more electrical conductors are separated from each other by respective distances and by one or more dielectric materials.