Abstract: The embodiments disclosed herein relate to a method for generating time-resolved images of an examination object, which executes a cyclical movement, and to a magnetic resonance device, and a computer program product herefor. According to a first aspect, at least one spatial magnetization pattern with spatial magnetization differences is generated during a magnetization of the examination object. Furthermore, magnetic resonance signals of the examination object are acquired after generating the spatial magnetization pattern throughout at least one cycle of the cyclical movement. At least one k-space is undersampled here during the acquisition of the magnetic resonance signals. Time-resolved images are generated based on the acquired magnetic resonance signals.

Abstract: In MR imaging of a predetermined volume segment of a living examination subject, the examination subject is stimulated with a defined stimulation pattern, MR data of the predetermined volume segment, are acquired, and MR images based on the MR data are generated that depend on the stimulation pattern. The predetermined volume segment is an internal organ or muscle tissue of the examination subject.

Abstract: In a magnetic resonance method and apparatus for determining an item of deformation information of an examination object that exhibits a cyclical movement within an examination subject, a spatial magnetization pattern is generated in an MR scanner, and MR signals are acquired from the subject during at least two cycles of the cyclical movement, with the spatial magnetization exhibiting differences in a subsequent cycle of the movement compared to an earlier cycle. Segmented subsequent MR images are acquired in a subsequent cycle and the examination object is localized therein. This localization of the examination object is then used to localize the examination object in segmented earlier MR images from the earlier cycle, and the item of deformation information is determined in a spatial direction from the segmented earlier MR images.

Abstract: For the generation of a magnetic resonance (MR) image of a predetermined volume segment of a living subject, a tracking factor is determined for each of different regions of the volume segment, from which the position of the respective region can be determined depending on a position of a moving area of the subject. MR image data of the volume segment are acquired for different positions of the moving area. The position of the moving area is calculated depending on the position and the tracking factor of the respective region, and the MR image data of the respective region are reconstructed using the MR image data of the volume segment corresponding to the calculated position of the moving area. The MR image of the predetermined volume segment is generated as a combination of the constructed MR image data of the regions.

Abstract: A shortened version of the MOLLI sequence (Sh-MOLLI) is described which generates rapid and high-resolution myocardial spin-lattice (T1) maps. The Sh-MOLLI technique is based on a significant abbreviation of pre-existing TI sampling scheme combined with the use of processing logic to bypass the major side effects of the above sampling scheme abbreviation and distinguish between long and short T1 relaxation times in order to conditionally utilize available TI samples for non-linear T1 fitting.

Abstract: In a method and medical imaging apparatus, for generating medical image data records, raw data of the examination object are acquired by operation of a medical imaging scanner, a reconstruction algorithm issued for reconstructing a medical image data record on the basis of raw data and of a value of a physiological parameter. At least two medical image data records are created by applying the reconstruction algorithm at least twice to the acquired raw data using a different virtual value of the physiological parameter each time. The at least two medical image data records are provided from the reconstruction computer.

Abstract: In a method and device for generating 4D flow images by operation of a magnetic resonance system, a volume flow data record is recorded, wherein the flow is encoded in a single direction. This is subsequently repeated with all the flow encoding directions. From the raw data associated with the individual flow encoding directions, phase images and magnitude images are calculated. Deformation fields are calculated on the basis of the magnitude images. The deformation fields are applied to the calculated phase images. Finally, a 4D flow velocity field is calculated, on the basis of a phase difference reconstruction of the corrected phase images.

Abstract: A system and method for regression-based segmentation of the mitral valve in 2D+t cardiac magnetic resonance (CMR) slices is disclosed. The 2D+t CMR slices are acquired according to a mitral valve-specific acquisition protocol introduced herein. A set of mitral valve landmarks is detected in each 2D CMR slice and mitral valve contours are estimated in each 2D CMR slice based on the detected landmarks. A full mitral valve model is reconstructed from the mitral valve contours estimated in the 2D CMR slices using a trained regression model. Each 2D CMR slice may be a cine image acquired over a full cardiac cycle. In this case, the segmentation method reconstructs a patient-specific 4D dynamic mitral valve model from the 2D+t CMR image data.

Abstract: In a method for computing MR images of an examination object that performs a cyclic movement, MR signals are detected over at least two cycles of the cyclic movement. In each of these cycles, data for multiple MR images are recorded. Over these cycles, a magnetization of the examination object that influences the MR images approaches a state of equilibrium in a second of these cycles is closer to the state of equilibrium than in a first of these cycles. Movement information for various movement phases of the cyclic movement of the examination object is determined using the MR images from the second cycle, with movement information of the examination object determined for each of the various movement phases. Movement correction of the examination object is carried out in the MR images of the first cycle using the movement information determined in the second cycle.

Abstract: Phase sensitive T1 mapping is provided in magnetic resonance (MR). The phase from samples of a modified Look-Locker inversion recovery sequence may be used to normalize contrast, allowing for accurate motion registration without extra information acquisition. The sign may be estimated, allowing T1 mapping with a single application of a non-linear fit.

Abstract: In a method and magnetic resonance system to determine a flow coding for a flow measurement with the magnetic resonance system, in order to determine the optimal flow coding, a flow pre-measurement with multiple different flow codings is conducted within a slice within a body to be examined, each of these codings allowing flow velocities to be detected with a sensitivity dependent on the respective coding. A velocity distribution of the non-slice-location-specific flow velocity values is generated from all of the results of this flow pre-measurement by a common Fourier transformation. The optimal flow coding for the flow measurement is then determined based on this velocity distribution.

Abstract: In a method and apparatus for magnetic resonance imaging, in order to create a T1 map, an pulse sequence is used that includes at least one exposure cycle, wherein the exposure cycle includes an inversion pulse, a saturation pulse quantity of one or more saturation pulses and a readout step quantity of one or more readout steps. Within the exposure cycle, at least one saturation pulse of the saturation pulse quantity follows the inversion pulse and at least one readout step of the readout step quantity follows the at least one saturation pulse.

Abstract: In a method for optimization of a flow coding with switching of an additional bipolar dephasing gradient pair, used in a magnetic resonance (MR) phase contrast angiography, the strength of the flow coding is selected depending on the flow velocity in the vessels that should be depicted. MR signals of an examination region are acquired with continuously running overview measurements, with an operator-selected flow coding strength. After the selected flow coding strength is adopted automatically for the next measurement of the continuously running overview measurements, and two partial measurements with different flow codings are implemented for each selected strength and a phase difference image from the two partial measurements is calculated and depicted in real time, and the selected flow coding strength is automatically adopted for the MR phase contrast angiography.

Abstract: MR signals are acquired with a method for phase contrast magnetic resonance (MR) imaging with speed encoding, in order to acquire raw data for multiple MR images. The multiple MR images are reconstructed. For this purpose, matrix elements are determined for numerous matrices, wherein the sum of the numerous matrices results in a pixel matrix. The pixel matrix has matrix elements that represent the pixel values for a reference MR image with flow compensation. The pixel matrix has further matrix elements that represent the pixel values for the at least one MR image with speed encoding. The matrix elements of the numerous matrices are determined such that a first matrix of the numerous matrices fulfills a first condition.

Abstract: In a method and a magnetic resonance system to automatically determine parameters of a phase contrast flow measurement, a phase contrast pre-measurement with a flow coding sequence is implemented in a predetermined volume segment of an examination subject, and the flow coding sequence is varied in terms of its parameters so that a pre-measurement is respectively implemented for multiple different parameter sets of the flow coding sequence. A model is automatically determined with which a dimension of a phase error can be determined for each parameter set in the flow measurement, in that phase values of the pre-measurement which is implemented with the flow coding sequence with the respective parameter set are analyzed. Those parameters of the flow measurement at which the dimension of the phase error is smallest are automatically determined.

Abstract: In a method and a magnetic resonance tomography system, at least two temporally separate original data sets are acquired with one phase measurement value being acquired for each pixel in each original image data set. An optimization technique for the shared calculation of corrected phase values for the pixels in the data sets is implemented in a computer, wherein the corrected phase values of the pixels in a first of the data sets is in each case dependent at least on the phase measured value of the pixel at the same location in a second of the data sets which is recorded beforehand or afterwards, and the corrected phase values of the pixels in the second data set are in each case dependent at least on the phase measured value of the pixel at the same place in the first data set. Corrected image data sets are generated from the corrected phase values.

Abstract: A computer-implemented method for determining magnetic field inversion time of a tissue species includes generating a T1-mapping image of a tissue of interest, the T1-mapping image comprising a plurality of T1 values within an expected range of T1 values for the tissue of interest. An image mask is created based on predetermined identification information about the tissue of interest. Next, an updated image mask is created based on a largest connected region in the image mask. The updated image mask is applied to the T1-mapping image to yield a masked image. Then, a mean relaxation time value is determined for the largest connected region. The mean relaxation time value is then used to determine a time point for nulling longitudinal magnetization.

Abstract: A method for performing motion compensation in a series of magnetic resonance (MR) images includes acquiring a set of MR image frames spanning different points along an MR recovery curve. A motion-free synthetic image is generated for each of the acquired MR image frames using prior knowledge pertaining to an MR recovery curve. Each of the acquired MR images is registered to its corresponding generated synthetic images. Motion within each of the acquired MR image is corrected based on its corresponding generated synthetic image that has been registered thereto.

Abstract: In a method and a device for phase-sensitive flow measurement of a volume segment of an examination subject in a measurement system, the volume segment is divided into multiple partial volume segments and the following steps are executed repeatedly until the volume segment has been completely measured: movement of a table such that a center of one of the partial volume segments to be measured essentially corresponds to the isocenter of the magnetic resonance system, and implementation of the phase-sensitive flow measurement for the partial volume segment to be measured while the center of the partial volume segment essentially corresponds to the isocenter.

Abstract: In a method and magnetic resonance (MR) system to generate an MR phase contrast angiography image of an examination subject, velocity-dependent phase information is impressed on moving spins in the examination subject by switching additional bipolar coding gradients that are in addition to the basic phase coding and readout gradients. For the creation of the MR phase contrast angiography images, the MR signals of the examination subject are read out in raw data space with a non-Cartesian acquisition pattern during a readout gradient. The additional bipolar coding gradients switched such that they proceed along a coordinate system that corresponds to the non-Cartesian acquisition pattern, and such that a coordinate axis of this coordinate system proceed along the readout gradient.