摘要:
A controller of a magnetic resonance system outputs a low frequency base signal to a conversion device. While outputting the base signal to the conversion device, the controller outputs an oscillator control signal to an oscillator. The oscillator outputs a frequency signal corresponding to the oscillator control signal to the conversion device. The conversion device converts the frequency signal into a high frequency transmit pulse with the aid of the base signal and outputs the transmit pulse to a magnetic resonance transmit antenna. The magnetic resonance transmit antenna applies a high frequency field corresponding to a transmit pulse to an examination volume of the magnetic resonance system. The controller varies the oscillator control signal output to the oscillator while outputting the base signal to the modulator. The transmit pulse) has a larger bandwidth than the base signal.
摘要:
A controller of a magnetic resonance system outputs a low frequency base signal to a conversion device. While outputting the base signal to the conversion device, the controller outputs an oscillator control signal to an oscillator. The oscillator outputs a frequency signal corresponding to the oscillator control signal to the conversion device. The conversion device converts the frequency signal into a high frequency transmit pulse with the aid of the base signal and outputs the transmit pulse to a magnetic resonance transmit antenna. The magnetic resonance transmit antenna applies a high frequency field corresponding to a transmit pulse to an examination volume of the magnetic resonance system. The controller varies the oscillator control signal output to the oscillator while outputting the base signal to the modulator. The transmit pulse) has a larger bandwidth than the base signal.
摘要:
In a method and magnetic resonance apparatus to continuously correct phase errors in a magnetic resonance measurement sequence in which multiple sequentially radiated, multidimensional, spatially-selective radio-frequency excitation pulses are used, multiple calibration gradient echoes are acquired in a calibration acquisition sequence and a correction value for a phase response and a correction value for a phase difference are calculated from the multiple calibration gradient echoes. Furthermore, an additional radio-frequency excitation pulse is radiated takes into account the correction values.
摘要:
In a method and magnetic resonance system to correct phase errors in multidimensional, spatially selective radio-frequency excitation pulses in a pulse sequence used to operate the system to acquire magnetic resonance data, a multidimensional, spatially selective radio-frequency excitation pulse is radiated and multiple calibration gradient echoes are acquired. A phase correction and a time correction of the multidimensional, spatially selective radio-frequency excitation pulse is then calculated.
摘要:
A method for creating an image data set using a magnetic resonance system including at least two RF transmit coils includes, for each RF transmit coil, calculating a value for a susceptibility magnetic field gradient to be corrected from the Gs map in combination with the B1 map of the RF transmit coil. The method includes, for each RF transmit coil, calculating a time delay of the excitation pulse. The method also includes calculating a complex weighting factor for scaling the pulse profile for each RF transmit coil to achieve an as uniform as possible deflection of the magnetization by the excitation pulse over the area under examination, and passing through the imaging sequence. The RF transmit coils each emit an excitation pulse with the calculated time delay and with a pulse profile scaled according to the calculated complex weighting factors.
摘要:
In a magnetic resonance (MR) method and system for correction of phase information in MR images of a predetermined volume segment of an examination subject, a basic magnetic field is applied and MR data of the predetermined volume segment are acquired and evaluated such that phase information is calculated for each image element of the predetermined volume segment. A navigator signal is acquired that detects an unintentional change of the basic magnetic field that is caused by movements of the examination subject or by the magnetic resonance system itself. The phase information is corrected with this navigator signal.
摘要:
A method and a control sequence determination device for the determination of a magnetic resonance system activation sequence including at least one high-frequency pulse sequence to be transmitted by a magnetic resonance system are provided. A current B0 map and optionally a target magnetization are acquired. In addition, a k-space trajectory type is determined. An error density is calculated in a k-space based on the current B0 map and optionally based on the target magnetization using an analytic function. This analytic function defines an error density in the k-space as a function of the current B0 map and optionally the target magnetization. Taking account of the error density in the k-space, a k-space trajectory of the specified k-space trajectory type is determined. The high-frequency pulse sequence is determined for the k-space trajectory in an HF pulse optimization process.
摘要:
A system adaptively processes MR image data to accommodate variation in perfusion time of a vessel fluid. An MR image data acquisition device initiates acquisition of a first image set comprising multiple different individual images having a set of corresponding different physical slice locations through a patient anatomical volume and being acquired at a corresponding first set of times and in a first order relative to a time of blood tagging of a patient. The MR image data acquisition device initiates acquisition of a second image set comprising multiple different individual images having the set of corresponding different physical slice locations through the patient anatomical volume and being acquired at substantially the corresponding first set of times and in a second order, different to the first order, relative to the time of blood tagging of the patient. At least one computer combines and averages image data representing the same corresponding image slice in both the first and second image sets and acquired at different times relative to the time of blood tagging of the patient and sends the combined and averaged image data representing the same corresponding image slice to a destination.
摘要:
In a method and system to generate magnetic resonance (MR) images by MR data are acquired by a pure phase-coded imaging in k-space having a predetermined set of possible measurement points, with the MR data being acquired only for a predetermined subset of the measurement points of this set. An image is reconstructed from the acquired measurement points of the subset such that information about un-acquired measurement points of the set is also obtained.
摘要:
Disclosed is a method and apparatus for recording measured data from a patient by taking movements into account by use of a medical device designed both for recording motion-related measured data and for recording nuclear medicine measured data. The method may include recording nuclear medicine measured data by use of the medical device, simultaneously recording motion-related measured data by use of the medical device, determining at least one motion information item relating to at least one movement of the patient and/or at least one movement inside the body of the patient during the ongoing measured data recording by evaluating at least a portion of the previously recorded motion-related measured data, and carrying out motion correction for at least a portion of the nuclear medicine measured data by use of the computational device in parallel with recording the measured data.