Abstract: The invention concerns a method for reconstructing medical image data which has access to free capacities of at least two computers and manages the use thereof for the purposes of the reconstruction. The method is a particularly reliable alternative to the reconstruction of medical image data based on algorithms that would require a working memory of above-average size.

Abstract: A computer-implemented method for performing isotropic reconstruction of Magnetic Resonance Imaging (MRI) data includes receiving a stack of slices acquired by an MRI device in two or more directions and reslicing the stack of slices into (i) an acquired view stack comprising high-resolution slices acquired in-plane, and (ii) a reslice stack comprising degraded slices acquired out of plane. An estimated slice profile is generated based on the stack of slices and the acquired view stack is convolved with the estimated slice profile to yield a simulated distorted slice stack. The simulated distorted slice stack is subtracted from the acquired view stack to yield a high-frequency band estimate and the high-frequency band estimate is combined with the reslice stack to yield isotropic reconstruction results.

Abstract: A method for generating motion information for an at least partially moving examination region includes outputting at least one first excitation signal with a first frequency band. The first excitation signal is picked up with a receive coil arrangement of a magnetic resonance system. The at least one coil of the receive coil arrangement is configured to pick up a receive frequency band that includes the first frequency band. At least one item of motion information for the examination region is determined from the picked up first excitation signal.

Abstract: In a method to correct an EKG signal, the EKG signal is acquired, and used for R-spike triggering, during a magnetic resonance (MR) image acquisition sequence that produces interference signals in the EKG signal generated by gradient jumps, wherein the gradient jumps repeat at a fixed time interval, and wherein the duration of a cardiac cycle measured via the EKG signal is at least five times the time interval. During at least a first cardiac cycle, immediately after detection of the R-spike in the EKG signal no detection of the R-spike for triggering takes place for a dead time that is shorter than the duration of the cardiac cycle and during which the MR sequence is already running, and the EKG signal is acquired in that dead time as a reference signal. The reference signal is analyzed to extract interference signals that respectively repeat after the time interval, which are used to determine a correction signal having a duration equal to the time interval.

Abstract: In a method and apparatus to reduce movement artifacts in magnetic resonance images an essentially unmoving area of a region to be imaged is located in a region of high sensitivity of a first group of individual local antennas, and a moving area is located in the region of high sensitivity of a second group of local antennas. Spatially coded magnetic resonance signals are received by a first group of the local antennas and are individually processed further. Spatially coded nuclear magnetic resonance signals are received by the second group of local antennas and are combined with a weighting, using weighting factors. The weighting factors are determined so as to reduce gradient of the weighted, combined, spatially dependent sensitivity of the local antennas of the second group.

Abstract: In a method for operating a medical imaging apparatus having subsystems, a control protocol assigned to a scan sequence to be performed is provided to a control computer that determines sequence control data for the control protocol, which define different functional subsequences of the scan sequence. Different effective volumes are assigned to each functional subsequence, and current ambient conditions of the apparatus are determined for the sequence control data and associated effective volumes, for a series of states of physiological processes that occur during the scan sequence. Control signals for the scan sequence are determined from the sequence control data, the effective volumes and the current ambient conditions per observed state, that optimize the functional subsequences of the scan sequence locally.

Abstract: In a method for operating a medical imaging examination apparatus having multiple subsystems controlled by a control computer in a scan sequence, a control protocol for the scan is provided to the control computer, which determines sequence control data for the control protocol that define different functional subsequences of the scan, with different effective volumes assigned to each functional subsequence. Current ambient conditions of the apparatus are determined that are decisive for the determined relevant sequence control data and associated effective volumes. Control signals for the scan are determined from the sequence control data, the effective volumes and the current ambient conditions determined that optimize the functional subsequences of the scan.

Abstract: In a method for operating a medical imaging apparatus having subsystems, a control protocol assigned to a scan sequence to be performed is provided to a control computer that determines sequence control data for the control protocol, which define different functional subsequences of the scan sequence. Different effective volumes are assigned to each functional subsequence, and current ambient conditions of the apparatus are determined for the sequence control data and associated effective volumes, for a series of states of physiological processes that occur during the scan sequence. Control signals for the scan sequence are determined from the sequence control data, the effective volumes and the current ambient conditions per observed state, that optimize the functional subsequences of the scan sequence locally.

Abstract: In a method for operating a medical imaging apparatus having multiple subsystems, a control protocol assigned to a scan sequence to be performed is provided to a control computer that determines sequence control data for the control protocol, which define different functional subsequences of the scan sequence. Different effective volumes are assigned to each functional subsequence, and current ambient conditions of the apparatus are determined for the sequence control data and associated effective volumes. Control signals for the scan sequence are determined from the sequence control data, the effective volumes and the current ambient conditions that optimize the functional subsequences of the scan sequence locally, at least with regard to a sub-region of the respective effective volumes.

Abstract: In a method for determining time windows in a scan sequence, in which values of setting parameters of a scan can be changed during a current scan without adversely affecting the scan data obtained with the scan, comprising the following a scan sequence is loaded into a control computer, that then determines the time windows in the scan sequence in which values of setting parameters can be changed during a current scan, on the basis of an analysis of useful coherences in the scan sequence. The determined time windows are stored or processed so as to be available to operate an imaging apparatus to execute the scan sequence.

Abstract: In a method for operating a medical imaging examination apparatus having multiple subsystems, current ambient conditions in a scan volume of the apparatus are determined and stored in a global ambient condition parameter set. A control computer starts a scan sequence according to a selected scan protocol, and sequence control data that define different functional sub-sequences for the respective subsystems are provided to the control computer. Different effective volumes are assigned to each functional sub-sequence, and respective current sub-regions in the effective volume associated with the respective sub-sequence are determined, in which a volume optimization is to take place. Control signals for the scan sequence are calculated using the sequence control data, the global ambient condition parameter set, and the determined current sub-regions of the affected volumes, in order to optimize the functional sub-sequences at least with regard to the current sub-region of the assigned effective volume.

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 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: A method and device for establishing a protocol relating to a measurement sequence for controlling a magnetic resonance tomography system, the measurement sequence is segmented into various groups of partial modules that are similar to one another. A partial module that potentially generates the greatest physiological exposure for a patient is identified. Furthermore, a test is carried out by means of a model function to determine whether physiological limiting values are being observed in the measurement sequence for the partial module. If the physiological limiting values are not being observed, parameters influencing the measurement sequence are modified and the preceding test step is repeated.

Abstract: In a method for ascertaining a gradient correction value for magnetic resonance (MR) examinations with an MR apparatus, a measurement slice is selected, with the center of the measurement slice being located outside of the isocenter of the MR scanner of the MR apparatus. A radio-frequency pulse is applied simultaneously with a slice gradient. The radio-frequency pulse is switched off and a reslice gradient is applied. A measurement signal is acquired. A phase shift is determined from the measurement signal, and a gradient correction time or a gradient correction amplitude is calculated using the phase shift.

Abstract: To generate an MR image, acquired MR data are entered into k-space on multiple uniform trajectories in k-space within a predetermined time period. The trajectories are acquired chronologically in a predetermined order before a predetermined point in time, and in a different order after the point in time. The i-th trajectory after the point in time in the different order is adjacent to the (n?i+1)-th trajectory in the predetermined order (n is the number of trajectories acquired before and after the point in time). Two trajectories are adjacent if a distance between them is less than a predetermined threshold. Except for the (n?i+1)-th trajectory, none of the trajectories acquired before the point in time has a distance from the i-th trajectory that is less than the threshold. The predetermined time period is set to be at a middle of a time period after an RF excitation pulse, such that a contrast change within the predetermined time period proceeds as linearly as possible over time.

Abstract: In a method a magnetic resonance apparatus for generating at least two essentially parallel two-dimensional image data sets of an examination object by operation of a magnetic resonance scanner having a multi-coil array, a multiband radiofrequency pulse is radiated for exciting at least two slices, that are phase encoded by applying a phase encoding gradient. Scan signals produced by the excited slices are detected using each coil of the multi-coil array. In one of the excitation or the phase encoding, the phase of the scan signal in at least one slice to be modulated at least once such that the phase of the scan signal is different from the phase of the other slices. Image data sets are reconstructed as a function of the modulation of the phase of the scan signal in at least one slice and, in at least one slice, the multiband radiofrequency pulse has an amplitude and/or duration and/or pulse shape that is different from the other slice or the other slices.

Abstract: In a method and magnetic resonance (MR) system for determining at least one measuring point-in-time in a cardiac cycle for conducting diffusion measurements of the myocardium of an examination object, a sequence of MR images of the heart is acquired and a time curve of a parameter of the cardiac geometry is determined in the sequence of MR images. At least one mean of the parameter of the cardiac geometry is determined from the time curve of the parameter. For the determined at least one mean of the parameter, the associated point-in-time in the time curve of the parameter is determined in which the determined mean occurs, wherein the determined point-in-time defines the at least one measuring point-in-time in a cardiac cycle during which the diffusion measurements of the myocardium are carried out.

Abstract: In a magnetic resonance apparatus and a method for the operation thereof, a pulse sequence is employed that is composed of a number of pulse sequence segments, each including an excitation procedure and a readout procedure. For each of a number of slices of an examination subject that are to be simultaneously excited, the pulse sequence segment is repeated, as a pulse sequence segment pair, with a prephasing gradient pulse being generated between the respective excitations in the respective segments of the pair. The prephasing gradient is configured to cause a gradient moment for all gradients between the respective centers of the respective excitations to be zero. The respective rephasing gradient pulses in each pair of segments are similar, and the respective excitation pulses have different phases.

Abstract: A method for acquiring cine images using a magnetic resonance imaging (MRI) system includes selecting an asymmetric radial sampling scheme providing an asymmetric view of k-space corresponding to a desired image resolution. Radial k-space data is acquired using the asymmetric radial sampling scheme, wherein slice-orientation of the radial k-space data is continuously modified while acquiring the radial k-space data. A plurality of cine images are reconstructed from the radial k-space data using a compressed-sensing method.