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 and a magnetic resonance (MR) apparatus for diffusion-gradient MR imaging, vectors for the diffusion gradients are determined by generating a cuboid with edges that represent the maximum amplitudes that are achievable by the gradient system of the MR apparatus, and a spherical shell is also generated that represents limit values for effective gradient amplitudes. Areas of the spherical shell that are within the cuboid are used as end points of origin vectors that originate from the origin of the intersecting axes of the gradient system. Diffusion gradient vectors that are to be used for acquiring the diffusion-weighted MR data are then selected from these origin vectors dependent on fulfillment of a condition for producing a trace-weighted image with low artifacts.

Abstract: A method and system for determining a magnetic field map in a MR system based on position of a movable patient support of the MR system are provided, wherein a first resulting field map including position dependent information about a magnetic field distribution in a homogeneity volume including an examination volume of the MR system is provided when the movable patient support is located at a first position, wherein a stationary field map including information about a magnetic field distribution in the homogeneity volume is provided, which is independent of the position of the movable patient support, wherein a position dependent field map including information about a magnetic field distribution in the homogeneity volume mainly influenced by a position of the movable patient support is determined using the stationary field map and the first resulting field map, and wherein a second resulting field map in the homogeneity volume is determined when the movable patient support is located at a second position di

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 and apparatus for determination of phase distributions in MR imaging, a measured phase distribution of the region of interest is combined with at least one second phase value to form a combination-phase distribution, wherein the phase values of the combination-phase distribution are restricted to a defined presentation interval. A correction-phase distribution is generated, based on a known magnetic field distribution in the region of interest. The phase values thereof are not restricted to the defined presentation interval. A corrected combination-phase distribution is generated using the correction-phase distribution and the combination-phase distribution, in which the phase values are restricted to the defined presentation interval. An absolute combination-phase distribution is generated from the corrected combination-phase distribution, in which the phase values are not restricted to the defined presentation interval.

Abstract: A method for automatically updating planning of measurement volumes as a function of object motion during MRI examination of an object in which the planning images a specific subject/object anatomy by MRI, includes defining an object reference pose and a reference coordinate system for the reference pose at a time during MRI examination, with the reference coordinate system being used for planning the measurement volumes. During examination, information is obtained about an object pose change between a current object pose at the time and the reference pose. For each subsequent scan or single acquisition of imaging data during examination, pose change information is used for calculating a new coordinate system for the current pose and updating the planning of measurement volumes as a function of the new coordinate system so the imaged object anatomy remains the same throughout the scans or acquisitions of imaging data irrespective of object motion.

Abstract: In a method and computer for evaluating medical image data of an examination subject, a clinical marker of the examination subject is acquired that characterizes a status of the examination subject in relation to a physiological parameter, and a normal value range for the physiological parameter is ascertained that is matched to the status of the examination subject as a function of the clinical marker. Medical image data of the examination subject are acquired, and a value of the physiological parameter of the examination subject is determined using the medical image data. This value is compared with the normal value range matched to the status of the examination subject, and the result of the comparison is provided as an output.

Abstract: In a method for operating a medical imaging examination apparatus having multiple sub-systems, a control computer controls the sub-systems to execute a scan sequence in which magnetization in at least two subvolumes of an object being scanned is simultaneously manipulated by a sub-sequence and/or used for the scan data acquisition process. A control protocol assigned to the scan sequence is provided to the control device, and sequence control data for the control protocol are determined that define different functional sub-sequences of the scan sequence. Different effective volumes are assigned to each functional sub-sequence, taking into account the aforementioned sub-modules. Effective volume position data are provided to the control device that define the position and extent of the effective volumes assigned to the different functional sub-sequences.

Abstract: 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.

Abstract: In a method and magnetic resonance (MR) apparatus or optimizing a time progression of an MR control sequence that operates an MR scanner of the MR apparatus so as to execute at least two sequence modules, a property of a component of the magnetic resonance apparatus is detected, and a first requirement of the component is determined for a first sequence module of the at least two sequence modules. A second requirement of the component is detected for a second sequence module of the at least two sequence modules. The time progression of the at least two sequence modules is optimized, taking account of the property, the first requirement and second requirement.

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: A magnetic resonance image is generated by executing a scan sequence that is determined by at least one scan parameter. A first value of the at least one scan parameter is determined for a first subregion of an examination region, and a second value of the at least one scan parameter is determined for a second subregion of the examination region. The determination of the first value and the determination of the second value is implemented so that a value of a physical variable influenced by the first value and the second value of the at least one scan parameter does not transgress a pre-set threshold value. Subsequently, the scan sequence is executed by a magnetic resonance scanner and a magnetic resonance image is generated. The threshold value can be based, for example, on technical efficiency of the scanner and/or a physiological limitation of an examination object.

Abstract: In a magnetic resonance measurement sequence, an inversion pulse is applied that acts on a longitudinal magnetization of a first spin species and a second spin species, for example on a water portion and a fat portion. An excitation pulse is applied after a predetermined time period. At least one manipulation pulse is subsequently applied, respectively with associated gradient pulse.

Abstract: In a method and magnetic resonance (MR) apparatus for generating an approximated trace-weighted MR image of a subject, at least three diffusion-weighted MR images of the subject are created, based on different diffusion encoding directions and diffusion gradient fields with essentially equal diffusion encoding strengths. A weighting factor is determined by an optimization method based on spatial inhomogeneities of the diffusion gradient fields for each image point of the at least three diffusion-weighted MR images. Based on the weighting factors, the at least three diffusion-weighted MR images are combined to generate the approximated trace-weighted MR image. Furthermore, an ADC map is determined based on approximated trace-weighted images and the effective diffusion encoding strength. Furthermore, a trace-weighted MR image is synthesized with nominal diffusion encoding strength based on a trace-weighted image with effective diffusion encoding strength.

Abstract: Magnetic resonance (MR) data are acquired from a volume segment of an examination object and an MR image composed of multiple image pixels is reconstructed therefrom. For a magnetic field assumed to have been generated by the scanner, a summed field deviation is calculated, from which a respective displacement vector is calculated for each image pixel. A signal portion is assigned to each image pixel that has been displaced with the respective displacement vector from the respective image pixel. The summed field deviation is the sum of deviations caused by at least two of: non-linearities in gradient coils, Maxwell fields, field inhomogeneities independent of the gradients, and dynamic field disturbances.

Abstract: In a method to correct a signal phase in the acquisition of MR signals of an examination subject in a slice multiplexing method, in which MR signals from at least two different slices of the examination subject are detected simultaneously in the acquisition of the MR signals, a linear correction phase in the slice selection direction is determined for each of the at least two slices. An RF excitation pulse with a slice-specific frequency is radiated in each of the at least two different slices. A slice selection gradient is activated during a slice selection time period, during which the different RF excitation pulses are radiated in the at least two different slices, and the slice selection time period has a middle point in time in the middle of the slice selection time period, and the different RF excitation pulses temporally overlap for the at least two different slices.

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 magnetic resonance (MR) method and apparatus, MR signals are acquired in multiple diffusion measurements using a defined set of parameters in the respective measurements that differ in terms of at least one MR parameter from measurement-to-measurement, thereby producing a measured MR signal dataset. Multiple calculated datasets are calculated using a model, with a defined number of model parameters in each calculated dataset, but in different combinations, with each calculated dataset having an MR signal intensity. The measured MR signal having a closest match to the measured MR signal dataset, using a quality criterion based on the MR signal intensity, is identified, and the diffusion parameter is obtained from the calculated dataset having the closest match.

Abstract: In an acquisition of magnetic resonance (MR) data from a volume portion of an object, a set of a number of planned volume elements is predefined in the volume portion, wherein MR data are to be acquired from each of the planned volume elements. Furthermore, conditions that are to be fulfilled in the acquisition of the MR data of the planned volume elements are predefined. Dependent upon the planned volume elements and the conditions, a set of additional volume elements is determined. The MR data are acquired from at least two volume elements simultaneously, the at least two volume elements including one volume element from the set of the planned volume elements and one volume element from the set of the additional volume elements.

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.