Siemens Healthineers Ag

Adam Kettinger

Mario Zeller

Dominik Paul

Thorsten Feiweier

Flavio Carinci

Gudrun Ruyters

Miriam Van De Stadt-Lagemaat

Max Müller

In a method for slice-specific correction of scan data recorded for at least two slices simultaneously of an examination object using an EPI-SMS technique, navigator signals encoded in a slice selection direction using a bipolar readout gradient for the at least two slices temporally after a RF excitation pulse radiated into the examination object and temporally before the recording of scan data to be corrected may be simultaneously recorded. Mean navigator signal(s) from at least two of the recorded navigator signals of a same polarity may be determined. Single-slice navigator signals may be determined based on the mean navigator signal and a navigator signal having been recorded with the same polarity as the mean navigator signal(s), but with a different slice selection encoding. Slice-specific correction data from the single-slice navigator signals may be determined, and scan data may be corrected based on the slice-specific correction data.

Method for slice-specific correction of scan data recorded for at least two slices simultaneously by means of an echo-planar simultaneous multi-slice technique

A method for avoiding artifacts in measurement data captured using a magnetic resonance system which has a gradient unit. The method includes loading data which characterizes the gradient unit of the magnetic resonance system; loading a measurement protocol to be used for capturing the measurement data, wherein the measurement protocol includes gradients to be switched and RF excitation pulses and RF refocusing pulses to be irradiated, wherein, after irradiation of an RF excitation pulse, a train of at least two RF refocusing pulses is irradiated and measurement data is captured after each RF refocusing pulse; determining compensation gradients which, after the capture of the measurement data, are to be switched after a final RF refocusing pulse of the train of RF refocusing pulses associated with the RF excitation pulse and before a following RF excitation pulse as a function of the loaded measurement protocol and of the data which characterizes the gradient unit; and carrying out the measurement protocol using the determined compensation gradients.

Avoidance of artifacts in measurement data captured using a magnetic resonance system

A method for preparing magnetic resonance imaging of an object under examination is described. A plurality of representative pulse sequence segments are generated, each of which is associated with a reference gradient amplitude of the gradient pulse having the highest stimulation potential of the representative pulse sequence segment, and the stimulation potential of which is representative of a group of partially different pulse sequences. For each of the representative pulse sequence segments, a maximum gradient slew rate is determined for which a permitted maximum value of the stimulation potential is not exceeded. One of the representative pulse sequence segments is determined and selected, for a measurement protocol to be planned for a magnetic resonance imaging to be performed, according to the gradient amplitude of the gradient pulse having the highest stimulation potential of a pulse sequence segment of the pulse sequence on which the measurement protocol is based. The pulse sequence segment of the pulse sequence on which the measurement protocol is based is adjusted in such a way that a maximum gradient slew rate associated with the selected representative pulse sequence segment is also not exceeded by the pulse sequence segment of the pulse sequence on which the measurement protocol is based.

Preparing a magnetic resonance imaging method in compliance with stimulation-based limitations

A method for creating calibration data for processing accelerated measurement data of an object to be examined using a magnetic resonance system. The method includes recording measurement data sets using an acquisition acceleration method, recording calibration data sets, and determining processed measurement data sets from the accelerated measurement data sets using the calibration data sets so that effects of the acquisition acceleration method used are eliminated in the processed measurement data sets. The recording of the calibration data sets includes an application of at least one attenuation method for attenuating signals causing phase errors.

Creating calibration data for processing recorded measurement data of an object to be examined using an MR system

In a method for determining at least one test position for a test measurement to be recorded by means of a magnetic resonance system, a test image is recorded, and at least one test position is selected based on the test image. With methods for the compensation of effects of deviations of gradients actually generated during a readout duration from gradients planned for this readout time duration, the selection of test positions according to the disclosure based on a test image advantageously ensures that the test positions lie in a recording region favorable for the test measurement, e.g. also within an examination object to be examined in the test image. A higher image quality in MR images, which were generated using test measurements carried out at test positions positioned according to the disclosure, can therefore be achieved.

Determining test positions in a target volume for a magnetic resonance system test measurement to improve magnetic resonance image quality of the system

In a method for diffusion-weighted MR-imaging of an object, which undergoes a cyclic motion, a first sub-period type of the cyclic motion is predicted for a first acquisition timeframe, where the first sub-period type corresponds to one of two or more predefined characteristic types of sub-periods of the cyclic motion. A first amount of diffusion-weighting may be selected based on the first sub-period type. A first MR-acquisition may be carried out during the first acquisition timeframe, where a diffusion-weighting according to the first amount of diffusion-weighting is applied. An MR-image of the object is generated based on MR-data including a first MR-dataset obtained as a result of the first MR-acquisition.

Magnetic resonance imaging with a dynamic diffusion-weighting

A technique for slice-specific correction of scan data recorded for at least two slices simultaneously of an examination object via an EPI-SMS is provided. The technique comprises recording slice separation reference scan data, generating scan data that is to be corrected, and recording phase-encoded navigator signals simultaneously for the at least two slices after an RF excitation pulse radiated into the examination object and before the recording of scan data to be corrected. The at least one navigator signal is recorded for each possible polarity and different phase-encoding of the navigator signals that is used. The technique further comprises separating the navigator signals simultaneously recorded for the at least two slices into single-slice navigator signals using the slice separation reference scan data, determining slice-specific correction data from the single-slice navigator signals, and correcting scan data that is to be corrected by means of the slice-specific correction data.

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Erlangen, Germany

Adam Kettinger