Method for operating a magnetic resonance device, magnetic resonance device and computer program product

Abstract

A computer-implemented method for checking an MR measurement protocol, comprising: providing an initial MR measurement protocol, providing at least one boundary condition, generating at least two sub-protocols based on the initial MR measurement protocol, wherein the at least two sub-protocols include a sub-protocol for acquiring reference data, the reference data being suitable for performing an MR acceleration technique, and checking each of the at least two sub-protocols to see if the at least one boundary condition is met when applying the respective sub-protocol.

Description

The invention relates to a method for operating a magnetic resonance apparatus, a magnetic resonance apparatus and a computer program productIn medical technology, imaging by means of magnetic resonance (MR), also magnetic resonance tomography (MRI, is characterized. Magnetic Resonance Imaging, MRI), due to high soft tissue contrasts. In this case, a patient is typically positioned in an examination space of an MR device. During an MR measurement, according to an MR protocol, in particular an MR sequence, high-frequency (RF, is usually performed with the aid of a high-frequency antenna unit of an MR device. RF) transmission pulses are irradiated into the patient. The generated transmission pulses excite nuclear spins in the patient, as a result of which MR signals which are spatially encoded are triggered by gradient pulses. The MR signals are received by the MR device as MR data and used for the reconstruction of MR images.For operation of the radio-frequency antenna unit, the MR device usually comprises one or more radio-frequency amplifiers which amplify a signal describing the transmission pulse. The signal amplified by the high-frequency amplifier is transmitted to one or more antennas of the high-frequency antenna unit, so that these antennas can emit the desired transmission pulse. Such a radio-frequency amplifier is usually designed to store a specific amount of electrical charge, in particular in one or more capacitors, and to retrieve it in a short time if necessary, in particular when a transmission pulse is emitted by the radio-frequency antenna unit. However, the high-frequency amplifier is limited in particular with regard to its output power, i.e. when an MR sequence is used, the available output power represents a boundary condition to be observed which is dependent on the MR device, in particular on the nature of the MR device.By absorbing the transmission pulses in the body of the patient, energy, in particular thermal energy, is introduced into the body of the patient. The specific absorption rate (SAR) must not exceed predetermined limits in order not to compromise the safety of the patient. Thus, the specific absorption rate when using an MR sequence represents a boundary condition to be observed that is dependent on the patient.In addition, further boundary conditions are conceivable which are to be observed when using an MR measurement protocol for recording MR data of a patient by means of an MR device.The document DE 10 2014 206 636 A1 discloses a method for creating a protocol of a measurement sequence, in which the measurement sequence is adapted in order to adhere to physiological limit values.It can be regarded as an object of the present invention to provide a method that enables reliable and / or efficient compliance with at least one boundary condition when an MR measurement protocol is used. The object is achieved by the features of the independent claims. Advantageous embodiments are described in the dependent claims.Accordingly, a method for testing an MR measurement protocol is proposed. The MR measurement protocol is suitable for recording MR data of a patient by means of an MR device. In this case, it is checked whether at least one boundary condition is complied with when the MR measurement protocol is used. According to the method, an initial MR measurement protocol is provided. Furthermore, at least one, in particular power-limiting, boundary condition is provided, which is in particular dependent on the patient and / or the MR device. At least two sub-protocols are generated on the basis of the initial MR measurement protocol. Each of the at least two sub-protocols is checked whether the at least one boundary condition is complied with when the respective sub-protocol is used.The initial MR measurement protocol can be provided, for example, by means of a provision unit of the MR apparatus. For example, an MR measurement protocol can be called up from a database and / or can be input and / or modified by an input unit of the MR device.An MR measurement protocol, in particular the initial MR measurement protocol, can be, in particular, an MR imaging protocol. An MR measurement protocol, in particular the initial MR measurement protocol, can comprise in particular one or more MR sequences, in particular MR pulse sequences. The MR measurement protocol can in particular comprise a, preferably complete, set of, preferably optimized, parameters for a specific examination type. The measurement protocol can comprise, for example, information about a field of view (FOV) and / or a resolution of the MR measurement to be carried out.The generation of the at least two sub-protocols on the basis of the initial MR measurement protocol can comprise, in particular, a splitting and / or separation of the initial MR measurement protocol into two sub-protocols. For example, the initial MR measurement protocol can comprise a plurality of MR sequences, in particular a first MR sequence and a second MR sequence, which are to be carried out successively according to the initial MR measurement protocol. A first of the at least two sub-protocols can comprise, for example, the first MR sequence; a second of the at least two sub-protocols can comprise, for example, the second MR sequence. In particular, the plurality of MR sequences of the initial MR measurement protocol may be suitable for recording MR data for different purposes. For example, reference data can be recorded with the first MR sequence and image data can be recorded with the second MR sequence. (The reference data and the image data are different kinds of MR data.) In particular, the at least two sub-protocols represent different parts of an acquisition method that is described by the initial MR measurement protocol.The checking of each of the at least two sub-protocols for compliance with the at least one boundary condition is in particular a separate and / or separate and / or individual and / or independent checking of the respective sub-protocol. For example, a first subprotocol is checked separately and / or separately and / or independently of the second subprotocol. In particular, each of the at least two sub-protocols is checked on its own whether the at least one boundary condition is complied with during its application. For example, during the test, a check is made on the basis of a piece of propagation time information of all RF pulses of the (partial) protocol as to whether or not a radio-frequency amplifier is overloaded at a specific time.Advantageously, by separately checking the at least two sub-protocols, complex dependencies between parts of the recording method can be avoided. Advantageously, there is still enough room to make the imaging as efficient as possible. Advantageously, it is thereby possible to avoid overloading a user interface with a plurality of parameters.If the check reveals that the at least one boundary condition is not complied with for a sub-protocol of the at least two sub-protocols, the sub-protocol is advantageously adapted, such that the at least one boundary condition is complied with when the sub-protocol is used.The adaptation of the subprotocol is preferably carried out separately and / or separately and / or individually and / or independently. The adaptation of the sub-protocol is preferably carried out separately and / or separately and / or individually and / or independently of any adaptation of another sub-protocol. In particular, each sub-protocol to be adapted is adapted independently of possibly other sub-protocols to be adapted. In particular, the adaptation of the partial protocol takes place (in an analogous manner to the checking of the partial protocol) per se.Predetermined values of adjustment parameters are preferably predefined for the adjustment of the sub-protocol, such as a minimum flip angle, a maximum repetition time (TR) and / or a minimum recording range. The minimum recording region can be defined, for example, by a minimum number of k-space lines to be recorded. Furthermore, an order may be predefined in which the predetermined adaptation parameters for compliance with the at least one boundary condition are changed. In particular, the adaptation of the partial protocol is ended if compliance with the at least one boundary condition has been reached after a change in an adaptation parameter. A change according to the order of subsequent adjustment parameters is therefore not performed. For example, the flip angle is first changed as the adjustment parameter; if the change in the flip angle does not yet result in the at least one boundary condition being complied with, TR, for example, is then changed in order to achieve the compliance.Preferably, a variation of several adjustment parameters (such as flip angles, TR and / or recording area) is carried out in order to achieve that the at least one boundary condition is complied with when applying the partial protocol.The at least one boundary condition can in particular be a power-limiting boundary condition or comprise a power-limiting boundary condition. Such a boundary condition can describe, for example, a power limit, in particular a maximum power capability, of a radio-frequency amplifier of the MR device. Such a boundary condition can describe, in particular, an electrical recharging capability and / or a maximum electrical charging capacity and / or a limitation to avoid overheating of a radio-frequency amplifier of the MR device. The more generous a high frequency amplifier is dimensioned, the less rapidly it usually encounters its power limits.The recharging capability can be described in particular by a rate at which electrical recharging of the high-frequency amplifier takes place. This can be expressed, for example, in the unit coulomb / second. The maximum electrical charging capacity can be described in particular by the maximum electrical charge, which can be (temporarily) stored and dissipated for transmitting transmission pulses. This can be expressed, for example, in the unit coulomb.A further boundary condition that is possible with respect to the MR device is the compliance with maximum strengths of magnetic field gradients and / or rates of change (slew rate) of magnetic field gradients, which the MR device is capable of applying. A magnetic field strength is usually expressed in the unit "mT / m"; a change rate of the magnetic field is usually expressed in the unit "T / m / s".The at least one boundary condition can describe in particular a maximum specific absorption rate of the patient. A specific absorption rate can be patient-specific in particular in that it is dependent on a mass of the patient. A further possible boundary condition related to the patient is the avoidance of too strong a stimulation, in particular nerve stimulation, in particular peripheral nerve stimulation (PNS), of the patient by application of magnetic field gradients.The specific absorption rate can be, in particular, the high-frequency energy absorbed per unit time and per kilogram of body weight after HF irradiation. Absorption of the RF energy can result in heating of the patient's body tissue. At unacceptably high local concentration of RF energy, RF burns may occur (local SAR). With a uniform distribution of the RF energy over the entire body, the load on the thermoregulation or cardiovascular system of the patient is decisive (whole body SAR). The at least one boundary condition can comprise, for example, a short-term SAR limit, in particular a 1s-SAR limit.The at least two sub-protocols preferably comprise a sub-protocol for recording reference data, wherein the reference data are suitable for carrying out an MR recording acceleration technique. The reference data preferably comprise MR acquisition data of reference lines in k-space.The at least two sub-protocols preferably comprise a sub-protocol for recording image data, wherein the image data are suitable for reconstructing at least one MR image taking into account the reference data. Such a subprotocol for recording image data preferably comprises an imaging sequence. One or more MR images can preferably be reconstructed from the image data. The image data usually contain the essential diagnostic information of the patient in the MR images. In contrast, the reference data are preferably used only auxiliaryly for the reconstruction of the image data.The MR imaging acceleration technique may include, for example, a parallel imaging technique. By using parallel imaging techniques with a plurality of parallel-operating receiving coils (PAT) in MR imaging, the acquisition time of the image data can advantageously be significantly reduced or a significantly higher resolution can be achieved with the same acquisition time. This is preferably done by recording a reduced number of k-space lines in, for example, the phase encoding direction in the spatial frequency space than is usually necessary to meet the Nyquist theorem. Such techniques are known as "partial parallel acquisition (PPA)". In order to reconstruct MR images with the same resolution from these subsampled k-space data, according to a subprotocol of the at least two subprotocols, subsampled and thus incomplete image data are preferably acquired with the aid of an arrangement of a plurality of receiving coils.Furthermore, according to a further partial protocol of the at least two partial protocols, reference data, in particular reference lines, are acquired. The reference lines are preferably respectively acquired by each of the plurality of receiving coils and preferably serve as calibration data points in order to adapt the incomplete data sets of different receiving coils to one another in order to generate complete image data. The reference lines can be detected, for example, at a low frequency in a central region of k-space. In the prior art, corresponding reconstruction methods, which are generally algebraic methods, are known, for example SENSE (Sensitive Encoding) and GRAPPA (Generalized Autocalibration PPA).The MR recording acceleration technique may further include, for example, a simultaneous multi-slice (SMS) technique and / or a deep resolve technique.The method preferably further comprises generating an, in particular single, final MR measurement protocol on the basis of the checked and optionally adapted at least two sub-protocols. Advantageously, the final MR measurement protocol can thereby be processed by the MR device like any usual MR measurement protocol. Advantageously, no further adaptation of the processing of the MR measurement protocols and / or processing of control data described by the MR measurement protocols is thereby necessary. Any modification outlay on the MR device can advantageously be kept low.The method preferably further comprises recording MR data of the patient according to the checked and optionally adapted at least two subprotocols, in particular according to the final MR measurement protocol. Advantageously, one or more MR images can be reconstructed on the basis of the MR data.Preferably, the generation of the at least two sub-protocols takes place on the basis of the initial MR measurement protocol and the checking of each of the at least two sub-protocols as to whether the at least one boundary condition is complied with when the respective sub-protocol is used is carried out only if a preceding check of the initial MR measurement protocol reveals that the at least one boundary condition is not complied with when the initial MR measurement protocol is used.Advantageously, this makes it possible to avoid the generation of the at least two sub-protocols on the basis of the initial MR measurement protocol and the checking of each of the at least two sub-protocols as to whether the at least one boundary condition is complied with when the respective sub-protocol is used.Furthermore, an MR device is proposed which is designed to carry out a method described above for testing an MR measurement protocol. For this purpose, the MR device preferably comprises a computing unit having one or more processors and / or memory modules. The computing unit can be designed, for example, as part of a system control unit of the MR device.The advantages of the proposed MR device essentially correspond to the advantages of the proposed method for testing an MR measurement protocol for recording MR data of a patient by means of an MR device, whether at least one boundary condition is observed when using the MR measurement protocol, which boundary conditions have been explained in detail above. Features, advantages or alternative embodiments mentioned here can likewise also be transferred to the other claimed subject matters and vice versa.Furthermore, a computer program product is proposed which comprises a program and is directly loadable into a memory of a programmable system control unit of an MR device and has program means, e.g. libraries and auxiliary functions, for executing a proposed method when the computer program product is executed in the system control unit of the MR device. The computer program product can comprise software with source code that still has to be compiled and bound or that only has to be interpreted, or executable software code that only has to be loaded into the system control unit for execution.The computer program product advantageously enables the proposed method to be executed quickly, identically repeatably and robust. The computer program product is preferably configured such that it can carry out the proposed method steps by means of the system control unit. The system control unit has the respective requirements, such as a corresponding working memory, a corresponding graphics card or a corresponding logic unit, so that the respective method steps can be carried out efficiently.The computer program product is stored, for example, on a computer-readable medium or on a network or server, from where it can be loaded into the processor of a local system control unit, which can be directly connected to the MR device or can be embodied as part of the MR device. Furthermore, control information of the computer program product can be stored on an electronically readable data carrier. The control information of the electronically readable data carrier can be designed such that it carries out a proposed method when the data carrier is used in a system control unit of an MR device.Examples of electronically readable data carriers are a DVD, a magnetic tape or a USB stick on which electronically readable control information, in particular software, is stored. When this control information is read from the data carrier and stored in a system control unit of the MR device, all proposed embodiments of the methods described above can be carried out.Further advantages, features and details of the invention are evident from the exemplary embodiments described below and on the basis of the drawings. Corresponding parts are provided with the same reference numerals in all figures.The following are shown: FIG. 1 shows an MR device, FIG. 2 shows a method for checking an MR measurement protocol, FIG. 3 shows a conflict in the absence of a boundary condition, FIG. 4 shows a modification profile of an initial MR measurement protocol.FIG. 1 schematically illustrates an MR apparatus 10. The MR device 10 comprises a magnet unit 11 which has a main magnet 12 for generating a strong and in particular temporally constant main magnetic field 13. In addition, the MR device 10 comprises a patient receiving region 14 for receiving a patient 15. In principle, however, a design of the patient receiving area 14 deviating therefrom is conceivable at any time. The patient 15 can be pushed into the patient receiving region 14 by means of a patient positioning device 16 of the MR device 10. For this purpose, the patient support device 16 has a patient table 17 configured to be movable within the patient receiving area 14.The magnet unit 11 further comprises a gradient coil unit 18 for generating magnetic field gradients which are used for spatial coding during imaging. The gradient coil unit 18 is controlled by means of a gradient control unit 19 of the MR apparatus 10. The magnet unit 11 further comprises a radio-frequency antenna unit 20, which in the present exemplary embodiment is designed as a body coil integrated firmly into the MR device 10. The radio-frequency antenna unit 20 is controlled by a radio-frequency antenna control unit 21 of the MR device 10 and radiates radio-frequency MR sequences into an examination space which is substantially formed by a patient receiving region 14 of the MR device 10. As a result, the main magnetic field 13 generated by the main magnet 12 is excited by atomic nuclei. MR signals are generated by relaxation of the excited atomic nuclei. The radio-frequency antenna unit 20 is basically designed to receive the MR signals. In this example, the MR device includes a local coil 27 disposed directly on the patient 15. The local coil 27 comprises a plurality of receiving coils which are spatially distributed in the local coil 27 and are each designed to receive MR data in the form of an MR signal.In order to transmit appropriate electrical signals to the radio-frequency antenna unit 20, the radio-frequency antenna control unit 21 comprises one or more radio-frequency amplifiers 26, which can amplify a control signal of the system control unit 22 to form a power signal. The high-frequency amplifier is designed to temporarily store an electrical charge, in particular precharge, which it then dissipates when a transmission pulse is amplified. Thus, the high-frequency amplifier is capable of amplifying transmission pulses with high edge steepness. For storing the electrical charge, the high-frequency amplifier preferably comprises at least one capacitor.For controlling the main magnet 12, the gradient control unit 19 and for controlling the radio-frequency antenna control unit 21, the MR apparatus 10 has a system control unit 22. The system control unit 22 centrally controls the MR device 10, such as performing a predetermined MR imaging sequence. In addition, the system control unit 22 comprises an evaluation unit, not shown in detail, for evaluating the MR signals which are detected during the MR examination. Furthermore, the MR device 10 comprises a user interface 23 which is connected to the system control unit 22. Control information such as imaging parameters, for example, and reconstructed MR images can be displayed on a display unit 24, for example on at least one monitor, of the user interface 23 for a medical operating personnel. Furthermore, the user interface 23 has an input unit 25, by means of which information and / or parameters can be input by the medical operating personnel during a measurement process.FIG. 2 shows an exemplary method for checking an MR measurement protocol for recording MR data of a patient by means of an MR device, whether at least one boundary condition is complied with when the MR measurement protocol is used.In S 10, an initial MR measurement protocol is provided, for example, to the system control unit 22. In S 11, for example, the system control unit 22 is provided with at least one boundary condition which is dependent on the patient 15 and / or the MR device 10. In S 20, it is checked, for example by the system control unit 22, whether the at least one boundary condition is complied with when the initial MR measurement protocol is used. If the at least one boundary condition is complied with, the MR device can immediately record MR data according to the initial MR measurement protocol in S 90.If, on the other hand, the at least one boundary condition is not met, at least two sub-protocols are generated, for example by the system control unit 22, in S 30 on the basis of the initial MR measurement protocol. Each of the at least two sub-protocols is then checked in S 40, S 50, for example by the system control unit 22, by itself, whether the at least one boundary condition is complied with when the respective sub-protocol is used. In the present example, two sub-protocols are assumed. The first subprotocol is checked in S40, the second subprotocol in S50. The sub-protocols are thus checked independently of one another.If the check in S 40, S 50 reveals that the at least one boundary condition for a sub-protocol of the at least two sub-protocols is not complied with, an attempt is made to adapt the respective sub-protocol such that the at least one boundary condition is complied with when the (adapted) sub-protocol is used. The possibly necessary adaptation of the sub-protocols can be effected, for example, by the system control unit 22. A solution is preferably sought by means of a solution algorithm and offered to the operating personnel. For this purpose, the complete sequence of the partial protocol is preferably simulated, i.e. each individual pulse, in particular an RF pulse and / or gradient pulse, is taken into account in the sequence at the time.If the check of the first subprotocol in S 40 thus reveals that the at least one boundary condition is not complied with for this purpose, an adaptation of the first subprotocol is carried out in S 60. The adapted subprotocol is then checked again in S 40. Analogously, the second subprotocol is adapted in S 70 if the check in S 50 reveals that the at least one boundary condition for the second subprotocol is not complied with.If, if appropriate, matched sub-protocols are present which meet the at least one boundary condition, a (single) final MR measurement protocol is generated on the basis of these sub-protocols in S 80. According to the final MR measurement protocol, MR data are recorded in S 90 by means of the MR device 10.The at least one boundary condition provided in S 11 and used for testing in S 20, S 40, S 50 can comprise, for example, a power limit of a radio-frequency amplifier 26 of the MR apparatus 10 and / or a power limit of a gradient coil unit 18 and / or a maximum specific absorption rate of the patient 15 and / or a maximum stimulation of the patient 15.The at least one boundary condition in the form of a power limit of a high-frequency amplifier 26 is to be explained with the aid of FIG. 3. According to an MR measurement protocol, sequence modules SM are usually executed by the MR device 10 over the course of time t. In particular, in addition to gradient pulses that are applied by gradient coil unit 18, such sequence modules may also include transmission pulses that are applied by radio-frequency antenna unit 20. As a result of the application of the transmission pulses, the high-frequency amplifier 26 discharges, i.e. the charge C of the high-frequency amplifier 26 decreases with time t. As a result, the high-frequency amplifier 26 can come into a state in which it is completely discharged and therefore cannot generate any further transmission pulses. One possible boundary condition for an MR measurement protocol is therefore to configure the MR measurement protocol such that this state does not occur.FIG. 4 shows by way of example how an initial MR measurement protocol P i provided in S 10 can be converted into a final MR measurement protocol. The initial MR measurement protocol P i here comprises two measurement procedures, which are represented here by a k-space to be measured in each case. The k-spaces shown here have k-space points represented by squares. Here, a solid square indicates a k-space point to be measured, and an open square indicates a k-space point not to be measured.According to a first MR sequence S 1 i reference data in the form of four central reference lines are to be recorded. According to a second MR sequence S2 i image data in the form of an incomplete data set is to be scanned in k-space; in this case, only every second k-space line is scanned.The reference lines are preferably recording data of a calibration measurement for a PPA method. In the case of PPA, k-space data, are usually recorded by a plurality of receiving coils. Each of the spatially independent receive coils carries certain spatial information which can be used to achieve complete spatial coding via a combination of the simultaneously acquired coil data. In the method, a calibration measurement is preferably carried out in a time period (referred to below as first time period, the sequence being unimportant). During the calibration measurement, reference data for predetermined calibration points in k-space are acquired using the plurality of receiving coils. The calibration points can comprise, for example, so-called reference lines in k-space. The reference data for the predetermined calibration points is preferably acquired simultaneously with the plurality of receiving coils.At another time, referred to below as second time period, a further measurement is carried out within the scope of the PPA method, the actual measurement for determining image data in k-space, from which MR images can be produced later by mathematical transformation of the data. During the actual measurement, an incomplete data record in k-space is acquired with each of the plurality of receiving coils. The acquisition of an incomplete data set takes less time than the acquisition of a complete data set, i.e. the PPA method is an MR acceleration technique.Complete data sets are then reconstructed by combining the incomplete data sets with the aid of the reference data, i.e. the image data are suitable for reconstructing at least one MR image taking into account the reference data. Complete image data sets can then be formed from these complete data sets with the aid of, for example, a Fourier transformation. The first time period and the second time period are different, i.e. the calibration measurement is not carried out at the same time as the actual measurement.From the initial MR measurement protocol P i two separate sub-protocols TP 1, TP 2 are generated in S 30. The first sub-log TP 1 comprises an initial sequence S 1 i for recording the reference lines. The second sub-protocol TP 2 comprises the imaging sequence. The two protocols TP1 and TP2 are sent independently of each other for checking in S40 and S50, respectively.The check yields either a positive result: the subprotocol can thus be carried out, i.e. no boundary condition is violated, or a negative result, i.e. at least one boundary condition is violated. In the latter case, an adjustment is made.In the case shown in FIG. 4, the check of the first subprotocol TP 1 in S 40 reveals, for example, that at least one boundary condition is not complied with. Then, adjustment is made in S 60. As specifications for the adaptation, for example, a minimum flip angle, a maximum repetition time and / or a minimum number of reference lines are used, and also an order in which these are to be changed. Thus, it is also possible to change whether, for example, the flip angle is to be changed first or the TR is to be changed first. As a result of the adjustment, for example, the number of reference lines can be reduced from 4 to 2, which is expressed in f in a changed final sequence S 1. Preferably, it can be provided that the adapted partial protocol is output to the operating personnel, for example by means of the user interface 23, for checking and / or confirmation as a proposal.In the case shown in FIG. 4, the check of the second subprotocol TP 2 in S 50 reveals, for example, that at least one boundary condition is complied with. No adaptation is then necessary, so that the final sequence S 2 f for recording the image data is identical to the initial sequence S 2 i. In S 80, the subsequences TP 1 and TP 2 are merged into a consistent overall protocol, the final MR measurement protocol P f.By splitting into sub-protocols TP 1, TP 2, complex dependencies between the parts of the recording method can be avoided with sufficient scope to configure the imaging as highly efficient as possible and not to overload the user interface 23 by too many parameters.Finally, it is pointed out once again that the methods described in detail above and the MR device illustrated are merely exemplary embodiments which can be modified in a wide variety of ways by the person skilled in the art without departing from the scope of the invention. Furthermore, the use of the indefinite article "a" or "an" does not exclude that the features in question can also be present multiple times.Likewise, the term "unit" does not exclude that the components in question consist of a plurality of interacting partial components, which may optionally also be spatially distributed.

Claims

Computer-implemented method for checking an MR measurement protocol, comprising: providing an initial MR measurement protocol, providing at least one boundary condition, generating at least two sub-protocols on the basis of the initial MR measurement protocol, wherein the at least two sub-protocols comprise a sub-protocol for recording reference data, wherein the reference data are suitable for carrying out an MR acceleration technique, checking each of the at least two sub-protocols whether the at least one boundary condition is complied with when applying the respective sub-protocol.The method of claim 1, wherein if the check reveals that the at least one constraint is not met for a sub-protocol of the at least two sub-protocols: adapting the sub-protocol such that the at least one constraint is met when applying the sub-protocol.Method according to Claim 2, wherein, for the adaptation of the subprotocol, an order is predefined in which predetermined adaptation parameters for compliance with the at least one boundary condition are changed.The method of any preceding claim, wherein the at least one constraint comprises a power limit of a radio frequency amplifier of the MR device.Method according to one of the preceding claims, wherein the at least one boundary condition comprises a power limit of a gradient coil unit of the MR device, a maximum specific absorption rate of the patient and / or a maximum stimulation of the patient.Method according to one of the preceding claims, wherein the reference data are suitable for carrying out a parallel imaging technique.Method according to Claim 6, wherein the at least two sub-protocols comprise a sub-protocol for recording image data, wherein the image data are suitable for reconstructing at least one MR image taking into account the reference data.Method according to one of the preceding claims, wherein the method further comprises: generating a final MR measurement protocol on the basis of the at least two sub-protocols checked and optionally adapted according to claim 2 or 3.Method according to one of the preceding claims, wherein the method further comprises: recording MR data of the patient according to the checked at least two partial protocols, and optionally according to claim 2, in particular according to the final MR measurement protocol generated according to claim 8.Method according to one of the preceding claims, wherein the generation of the at least two sub-protocols on the basis of the initial MR measurement protocol and the checking of each of the at least two sub-protocols as to whether the at least one boundary condition is complied with when the respective sub-protocol is used are carried out only if a preceding check of the initial MR measurement protocol reveals that the at least one boundary condition is not complied with when the initial MR measurement protocol is used.A MR apparatus configured to perform a method according to any one of claims 1 to 10.A computer program product comprising a program and directly loadable into a memory of a programmable system controller of an MR device, comprising program means for performing a method according to any of claims 1 to 10 when said program is executed in the system controller of the MR device.

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