In a magnetic resonance method and apparatus to determine a subject-specific B1 distribution of an examination subject in a measurement volume in the magnetic resonance apparatus, a first measurement data set of the examination subject is acquired using a first pulse sequence, a second measurement data set of the examination subject is acquired using a second pulse sequence, and a third measurement data set of the examination subject is acquired using a third pulse sequence. A first phase is determined from the first measurement data set, a second phase from the second measurement data set and a third phase from the third measurement data set. A relevant phase shift is calculated from the first phase, the second phase and the third phase, and the B1 distribution are determined from the calculated relevant phase shift.

The present invention provides a method and apparatus for generating a specific flip angle distribution in magnetic resonance imaging; the method uses a plurality of RF transmission coils combined with linear and nonlinear spatial encoding magnetic fields to generate a homogeneous flip angle distribution.

A plurality of stimulations is transmitted to tissue or other material using one or more transmitters. The plurality of signals associated with the excited tissue and the transmitted stimulations are measured. The measured signals are processed to generate field-related quantities, such as B1+ and/or MR signal maps. Field-related quantities are generated also from simulation, by calculating the one or more incident fields from a simulator model of the one or more transmitters and assuming a given distribution of electrical properties in the tissue or other material. Field-related quantities generated from simulation and experimental procedures are compared to each other. The assumed electrical properties distribution is updated and the procedure is repeated iteratively until the difference between simulated and experimental field-related quantities is smaller than a threshold.

A dynamic field camera arrangement for monitoring electromagnetic field behavior in a spatial region comprises a main magnetic field and a radiofrequency (RF) field limited to a first RF band, particularly in an MRI or NMR apparatus. The arrangement comprises a magnetic field detector set comprising a plurality of low-frequency magnetic field detectors, each one of said magnetic field detectors comprising a magnetic resonance (MR) active substance, means for pulsed MR excitation of said substance and means for receiving an MR signal generated by said substance, wherein said pulsed excitation and said MR detector signal is in a second RF band that does not overlap said first RF band. The MR signal receiving means comprise a first RF filter which suppresses RF signal from said first RF band and transmits RF signal from said second RF band.

A method for establishing a magnetic resonance system actuation sequence is described. A first number of field distribution maps are acquired for slices of the measurement region, and a radiofrequency pulse train is established on the basis thereof for the magnetic resonance system actuation sequence. This acquisition of the first number of field distribution maps may be brought about on the basis of an acquisition scheme. A reduced number of field distribution representation maps are established on the basis of the acquired field distribution maps, which field distribution representation maps represent the first number of acquired field distribution maps in accordance with a predetermined optimization criterion, and the radiofrequency pulse train is established on the basis of the field distribution representation maps.

The method according to the invention for the correction of measurement data acquired along Cartesian lines in k-space, which measurement data have been acquired by means of a pulse sequence in which gradients are switched simultaneously during the radiation of at least one non-selective excitation pulse, includes the steps of measurement data acquired with the pulse sequence are entered into k-space, i.e. entered into a memory organized as k-space, a pulse excitation profile is determined, and the acquired measurement data are corrected using the pulse excitation profile, the correction including a de-convolution operation in at least one of the three k-space directions. The correction of measurement data according to the invention allows an unrestricted use of pulse sequences, in particular gradient echo sequences, in which an excitation is implemented given already activated gradients (for example for noise reduction). A distortion due to superposition of an excitation with a pulse profile can be remedied via the method according to the invention.

In a method and test apparatus for determining a deviation in the homogeneity of a basic magnetic field of a magnetic resonance scanner, test vessels are positioned in a test plane that first and second positions along a direction in the scanner, and measurement data are acquired with the test vessels at said respective positions. The acquired measurement data are provided to a processor, wherein a deviation of the homogeneity of the basic magnetic field is determined based thereon.

A magnetic resonance imaging apparatus includes an imaging unit configured to carry out magnetic resonance imaging of a patient using a transmitting QD coil that allows at least one of phase and amplitude of a radio-frequency transmit pulse on at least one input channel of the transmitting QD coil to be adjusted independently of each other, and an adjustment unit arranged to adjust at least one of the phase and the amplitude of the radio-frequency transmit pulse according to imaging conditions.

A magnetic resonance imaging apparatus according to an embodiment includes an acquiring unit, a detecting unit, a deriving unit, and an imaging controller. The acquiring unit acquires three-dimensional image data including a target organ. The detecting unit detects an upper end position and a lower end position of the target organ in the three-dimensional image data. The deriving unit derives an imaging range of subsequent imaging performed after acquisition of the three-dimensional image data based on the upper end position and the lower end position of the target organ. The imaging controller controls performance of the subsequent imaging in accordance with the imaging range.

In a method and magnetic resonance apparatus for determining a B1 field map in a scanner of the apparatus, the B1 field map describing a local field distribution of a B1 field resulting from excitation pulses radiated in a measurement sequence, first and second measured values are acquired from a region in which nuclear spins are excited by an excitation pulse having an assigned flip angle, and a provisional flip angle is determined from the first and second measured values. A correction factor, dependent on the pulse shape of a selected excitation pulse, is then determined, and the provisional flip angle is multiplied thereby to obtain a corrected value for entry into said B1 field map.