High-quality magnetic resonance (MR) recordings are triggered with movements of an object, for example the heartbeat. In a method and apparatus for obtaining raw data reconstruction for an MR image, a spin-echo-based sequence is executed that includes applying a static magnetic field and applying a magnetization pulse train. A movement of the object to be imaged is detected and a target contrast for two tissue types of the object is prespecified. The repetition time of the pulse train is set in dependence on the movement of the object to be imaged, and the flip angle is set such that prespecified target contrast for the two tissue types is obtained at the set repetition time.

Method and apparatus for determining a flip angle for multi-tissue magnetic resonance scanning. The method including: determining multiple types of tissue of interest for MRI this time; acquiring a relationship between combined SSI MR signal strength of all the tissues of interest and flip angle of an SSI sequence; acquiring a maximum value of the combined SSI MR signal strength of all the tissues of interest; according to the maximum value of the combined SSI MR signal strength of all the tissues of interest, acquiring an optimum flip angle which causes the combined SSI MR signal strength of all the tissues of interest and contrast between the tissues of interest simultaneously to be optimal; and taking the optimum flip angle to act as a flip angle of an SSI sequence for multi-tissue MR scanning this time.

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.

Methods for correcting inhomogeneities of magnetic resonance (MR) images and for evaluating the performance of the inhomogeneity correction. The contribution of both transmit field and receiver sensitivity to signal inhomogeneity have been separately considered and quantified. As a result, their negative contributions can be fully corrected. The correction method can greatly enhance the accuracy and precision of MRI techniques and improve the detection sensitivity of pathophysiological changes. The performance of signal inhomogeneity correction methods has been evaluated and confirmed using phantom and in vivo human brain experiments. The present methodologies are readily applicable to correct signal intensity inhomogeneity artifacts produced in different imaging modalities, such as computer tomography, X-ray, ultrasound, and transmission electron microscopy.

In a method and magnetic resonance for calibrating a control sequence for the apparatus, having a first radio-frequency pulse and a second radio-frequency pulse, for a magnetic resonance examination of an examination region of an object, a first reference value for the first radio-frequency pulse for resonant excitation of a first substance is determined, and a second reference value for the second radio-frequency pulse for resonant excitation of a second substance is determined. The determination of the first reference value includes a selective excitation of the first substance and/or the determination of the second reference value includes a selective excitation of the second substance. The MR control sequence is calibrated by assignment, in a processor, of the first reference value to the first radio-frequency pulse and assignment of the second reference value to the second radio-frequency pulse.

In a method and apparatus for optimizing the signal-to-noise ratio (SNR) of a magnetic resonance (MR) dataset acquired by means of a magnetic resonance system having at least one transmit coil, a measurement protocol for an acquisition that is to be performed in order to obtain the MR dataset of a predefined measurement volume. A deviation of an actual flip angle from the predefined flip angle in a specific area of the predefined measurement volume is determined for a preset transmitter scaling. The transmitter scaling of the RF pulse is adjusted in order to correct the actual flip angle so that the actual flip angle is approximated to the predefined flip angle in the specific area. The MR dataset is acquired with the adjusted transmitter scaling.

A magnetic resonance imaging MRI method and apparatus for lengthening the usable echo-train duration and reducing the power deposition for imaging is provided. The method explicitly considers the t1 and t2 relaxation times for the tissues of interest, and permits the desired image contrast to be incorporated into the tissue signal evolutions corresponding to the long echo train. The method provides a means to shorten image acquisition times and/or increase spatial resolution for widely-used spin-echo train magnetic resonance techniques, and enables high-field imaging within the safety guidelines established by the Food and Drug Administration for power deposition in human MRI.

Acquiring 3D MRI data using spiral-in-out encoding trajectories includes calculating a variable flip angle RF series for use as refocusing pulses, wherein the RF series includes a plurality of refocusing RF pulses. A spoiler gradient waveform is applied along the spoiler gradient direction, wherein the computer alternately adds and subtracts partition encoding waveforms to the spoiler gradient waveform. The method reads MRI data from each encoding step during an MRI sequence. The MRI sequence inserts a spiral-in gradient before a first refocusing RF pulse from the RF sequence, overlaps a pre-winder lobe for the encoding trajectory with the spoiler gradient waveform having the partition encoding waveforms added therein, and overlaps a rewinder lobe for the encoding trajectory with the spoiler gradient waveform having the partition encoding waveforms subtracted there from.

A magnetic resonance system (1) includes at least one radio frequency (RF) transmit coil (6), an RF transmitter (34), an anthropometric unit (28), and an adaptive SAR unit (40). The at least one radio frequency (RF) transmit coil (6) transmits measured RF power to excite and manipulate magnetic resonance in tissues of a subject (57) in an examination region. The RF transmitter (34) controls the amount of transmitted RF power based on a specific absorption rate (SAR) for an imaging sequence. The anthropometric unit (28) determines a mass of a portion of the subject which receives the transmitted RF power based on a determined total mass. The adaptive SAR unit (40) adjusts a selected scan sequence based on the SAR parameters determined from the measured transmitted RF power and a measured reflected power, achieved IB.sub.|+I field, the mass of the portion of the subject which receives the transmitted RF power and applicable SAR parameter models stored in a SAR reference unit (46).

A method for operating a transmission device of a magnetic resonance device is provided. In order to actuate coil elements of a radiofrequency coil with different phases, phase differences in a reference plane are taken into consideration. In a first calibration measurement to be performed once for each transmission path, a first phase of a transmitted radiofrequency signal is measured by an internal measuring device installed permanently in the transmission device spaced apart from the reference plane. A second phase of the transmitted radiofrequency signal is measured by a second, external measuring device to be connected to the reference plane for the first calibration measurement. At least one phase of the first phase and the second phase is taken into consideration in the phase-accurate actuating of the coil elements and/or for correcting further measurements with the internal measuring device.