In order to optimize magnetic resonance (MR) images in spin echo-based imaging, MR raw data are acquired by applying a static magnetic field, an excitation pulse, a refocusing pulse, and an RF pulse at the same time point as an echo elicited by the pulses with the result that the magnetization in the negative z-direction is deflected by a flip angle. The flip angle is selected such that, given a specified repetition time of the excitation pulse, a predetermined contrast is provided for two specified tissue types of the subject to be imaged. An MR image is reconstructed from the acquired MR raw data.

In a Method and a device for magnetic resonance imaging of a subject using a spoiled gradient echo sequence, a B.sub.0 magnetic field strength of at most 1.5 T is used during the sequence. As part of the sequence a slice select gradient acting as a spoil gradient is played out. Substantially simultaneously with the slice select gradient a predetermined RF pulse is played out in the sequence, wherein a time-bandwidth product of the RF pulse is set so that a majority of the energy of the RF pulse is transmitted in its central main lobe.

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.

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 magnetic resonance imaging method, a first adjustment parameter is determined for presetting an initial contrast of a magnetic resonance image; a second adjustment parameter is determined for obtaining an optimized contrast of the magnetic resonance image and a specified data acquisition time of a blade artifact correction sequence; an optimized echo signal evolution curve is determined according to the first adjustment parameter and the second adjustment parameter; an actual variable flip angle train is calculated according to the optimized echo signal evolution curve; and the actual variable flip angle train is applied to a two-dimensional fast spin echo sequence, and the blade artifact correction sequence corresponding to the second adjustment parameter is used to acquire magnetic resonance signals and enable the magnetic resonance image to satisfy the optimized contrast.

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.

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.

Various embodiments include apparatus and methods to calibrate a nuclear magnetic resonance tool. Example calibration techniques may include using intended ninety degree pulses as a control mechanism to evaluate echo pulses from generating pulse sequences. Example calibration techniques may include comparing a sequence of measurement signals with a reference sequence. Additional apparatus, systems, and methods are disclosed.

The invention relates to a method for the hyperpolarization of a material sample (4), which hits a number of first spin moments (10) of a first spin moment type, wherein the number of first spin moments (10) is brought into interaction with a second spin moment (16) of a second spin moment type, wherein the first spin moments (10) are nuclear spin moments and the second spin moment (16) is an election spin moment, wherein the first and second spin moments (10, 16) are exposed to a homogeneous magnetic field (B), wherein the second spin moment (16) is polarized along the magnetic field (B), wherein the second spin moment (16) is coherently manipulated by means of a, preferably repeated, sequence (S) having a number of successive high-frequency pulses (P.sub.ki, P.sub.ki) temporally offset to each by durations (T.sub.ki, T.sub.ki, T), in such a way that a polarization transfer from the second spin moment (16) to the first spin moments (10) occurs, and wherein durations (T.sub.ki, T.sub.ki, T) inversely proportional to a Lamor frequency (.sub.Larmor) of the first spin moments (10) in the magnetic field (B) are inserted between high-frequency pulses (P.sub.ki, P.sub.ki).

In order to optimize magnetic resonance (MR) images in spin echo-based imaging, MR raw data are acquired by applying a static magnetic field, an excitation pulse, a refocusing pulse, and an RF pulse at the same time point as an echo elicited by the pulses with the result that the magnetization in the negative z-direction is deflected by a flip angle. The flip angle is selected such that, given a specified repetition time of the excitation pulse, a predetermined contrast is provided for two specified tissue types of the subject to be imaged. An MR image is reconstructed from the acquired MR raw data.