Method and device for planning an MR examination on an MRI system

Abstract

The invention relates to a method for planning an MRI examination on an MRI system, comprising the steps of: - providing geometric information (G) about an examination area (U), - providing quality information (Q), comprising information about the homogeneity of a main magnetic field and / or gradient fields in the examination area (U) and / or information about distortion correction of corrected images (B) of the examination area (U), - defining a number of homogeneity zones (H, H1) in the examination area (U), based on a determination of whether the values ​​of the quality information (Q) lie within a defined range, - determining position data based on the location and shape of the number of homogeneity zones (H, H1) and the examination area (U), and outputting the position data. The invention further comprises a device and an MRI system.

Description

The invention relates to a method and an apparatus for planning an MR examination on an MRI system and an MRI system.Magnetic resonance imaging (MRI) is an established examination method in medicine. In a strong, homogeneous magnetic field (also referred to as "BO" or "basic magnetic field"), which is superimposed by gradient fields, materials in the body are magnetically excited and their signals are measured.Some MR systems have a limited homogeneity of the basic magnetic field or a limited linearity of the gradient fields. This has the result that the area which can be used in a meaningful manner for imaging is limited in comparison to high-cost systems.A visible effect of the lower quality of the magnetic fields is that some recorded areas are no longer completely contained in the final image by effects of the distortion correction. They are basically cut off. Furthermore, during measurements, limitations of the fat saturation can occur. For these reasons, it may then occur that a body region (e.g. thorax) cannot be completely detected in large patients.The document US 2022 / 0397623 A1 describes a method which assists the examination personnel in planning on locator images in order to avoid regions cut off by the distortion correction. Unfavourable patient support during the preparation for measurement cannot be compensated for as a result, however.The document US 11540741 B2 describes a method for assisting the operating personnel in coil positioning and selection by means of light projection and 3D camera.It is an object of the present invention to specify a method and a device for planning an MR examination on an MRI system and an MRI system, with which the disadvantages described above are avoided.This object is achieved by a method according to claim 1, an apparatus according to claim 9 and an MRT system according to claim 13.A method according to the invention serves for planning an MR examination on an MRI system, i.e. in particular for monitoring whether an object to be examined has been suitably positioned or an examination region has been suitably selected. It comprises the following steps:providing geometric information about an examination region,providing quality information, comprising information about a homogeneity of a main magnetic field and / or gradient fields in the examination region and / or information about a distortion correction of corrected images of the examination region,defining a number of homogeneity regions in the examination region based on a determination as to whether values of the quality information lie in a defined value range,determining position data based on the position and shape of the number of homogeneity regions and the examination region and outputting the position data.The geometric information relating to the examination region is information which defines the position and size of the examination region and in particular also its shape. This can be done, for example, by defining a body region to be examined or by arranging the examination region in a virtual user interface. The examination region can be a region of the patient couch and an object on this region is considered to be the object to be examined, but the examination region is preferably a region of the object, in particular a three-dimensional region.The geometric information about the examination region can be provided by an operator, in particular by specifying the body region to be examined, e.g. "left foot".In this regard, it should be noted that the examination region can generally be shaped and placed completely according to the wishes of an operator and can perfectly project into regions at which the homogeneity of the basic magnetic field or gradient fields is deficient as soon as the patient table has been moved into the patient tunnel.The quality information includes information which provides information about the quality of the images to be expected. The quality is influenced by the local quality of the magnetic fields and, if appropriate, by the reconstruction used. For this purpose, the quality information comprises information:via homogeneity of a main magnetic field (at least) in the examination zone and / orvia homogeneity of gradient fields (at least) in the examination region and / orinformation for distortion correction of corrected images of the examination region.This distortion correction also reflects the homogeneity of the magnetic fields, since the distortion depends on local inhomogeneities.The quality information is basically known and specific to the MRT system used. It can be stored, for example, in a data record on a data memory of the MRT system and provided if necessary. However, it can also be measured, for example by measurements of the magnetic field.If the quality information is provided, a homogeneity range can be defined in the examination region. This is done based on a determination as to whether values of the quality information lie in a defined value range. For example, a limit value for the homogeneity of the basic magnetic field can be defined beforehand and it can be checked how this homogeneity appears in the examination region. Each position at which the homogeneity is above the limit value is assigned to the homogeneity range, the homogeneity is below it, then not. However, it is also possible to define a plurality of homogeneity ranges. This is preferably done by defining a plurality of limit values and a first homogeneity range comprises regions with the best homogeneity and further homogeneity ranges comprise regions with lower homogeneity (from respectively different value ranges with decreasing homogeneity).It should be noted here that, in a very simple embodiment, homogeneity regions can be two-dimensional and relate, for example, to the patient couch. However, since the magnetic fields and the objects under examination are three-dimensional, it is preferred that the homogeneity regions are also three-dimensional. It is particularly preferred that a homogeneity region extends at least over the entire volume of the object to be examined in the examination region. The volume can be determined, for example, by 3D camera images or estimated by a model of the object and its position.The position data is based on the position and shape of the number of homogeneity regions and the examination region. In a simple example, they can therefore comprise the position and size of rectangles on the examination table, but preferably they comprise the position and shape of three-dimensional volumes. However, the position data can also comprise data from a comparison of the position and shape of the number of homogeneity regions with the examination region, e.g. whether a foot is positioned optimally with respect to a homogeneity region.Position data can be output in different ways, but preferably in the form of a display of a representation of the number of homogeneity regions or in the form of control data.The display of a homogeneity region (or its representation) can be effected by a projection directly onto the patient couch or by display on a screen, wherein in particular an image of the examination region is overlaid with an image of the homogeneity region. Alternatively or additionally, however, a result of a comparison of a homogeneity region with the examination region can also be output, i.e. for example a warning that parts of the examination region or of the object to be examined are located outside the homogeneity region.An output of control data can be used to automatically drive the patient couch into another position. The control data are preferably sent to a unit which serves for positioning the patient couch or to a screen on which an operator can read the optimum positioning of the patient couch. This makes it possible to move the patient couch (optionally also automatically) in such a way that the examination region (this means here the part of an object to be examined or a body region to be examined) is aligned optimally with respect to the number of homogeneity regions. The expression "optimally aligned" here means that a maximum volume (or a maximum area) of the examination region is positioned within the homogeneity region with the best quality (the best values with respect to the quality information, in particular the best homogeneity)An apparatus according to the invention serves for planning an MR examination on an MRI system. It comprises the following components:a data interface configured to receive geometric information about an examination zone,a quality unit configured to retrieve quality information comprising information about homogeneity of a main magnetic field and / or gradient fields in the examination region and / or information about distortion correction of corrected images of the examination region,a homogeneity unit configured to define a number of homogeneity regions in the examination region based on a determination as to whether values of the quality information lie in a defined value range,a position unit configured to determine position data based on the position and shape of the number of homogeneity regions and the examination region and output the position data.The apparatus is preferably designed for carrying out a method according to the invention. The function of the components of the device has already been described in the course of the method.An MRT system according to the invention comprises an apparatus according to the invention and / or is configured to carry out a method according to the invention.The invention can be realized in particular in the form of a computer unit with suitable software. For this purpose, the computer unit can have, for example, one or more cooperating microprocessors or the like. In particular, it can be realized in the computer unit in the form of suitable software program parts. A realization largely through software has the advantage that computer units already used up to now can also be easily retrofitted with a software or firmware update in order to operate in the manner according to the invention. In this respect, the object is also achieved by a corresponding computer program product having a computer program which can be loaded directly into a storage device of a computer unit, having program sections in order to carry out all steps of the method according to the invention when the program is executed in the computer unit. In addition to the computer program, such a computer program product can optionally comprise additional components, such as documentation and / or additional components, also hardware components, such as hardware keys (dongles, etc.) for using the software.For transport to the computer unit and / or for storage on or in the computer unit, a computer-readable medium, for example a memory stick, a hard disk or another transportable or permanently installed data carrier, can be used, on which the program sections of the computer program that can be read in and executed by a computer unit are stored.Further, particularly advantageous embodiments and developments of the invention are evident from the dependent claims and the following description, wherein the claims of one claim category can also be developed analogously to the claims and description parts to another claim category and in particular individual features of different exemplary embodiments or variants can also be combined to new exemplary embodiments or variants.It is preferred that in one embodiment of the method the examination region is defined by retrieving information for examination, i.e. it is e.g. indicated which body part is to be examined and is automatically determined at a defined standard position of a patient where this body part typically lies. The accuracy can be further improved by camera images of the patient.Alternatively or additionally, it is preferred that the examination region is defined by positioning an MRI coil on a patient. In particular, the position of the coil on the patient couch is determined and the recording area of the coil or the area covered by the coil is defined as the examination area.Alternatively or additionally, it is preferred that the examination region is defined by a selection of an operator. Preferably, an operator can define position and size and in particular also the shape of the examination region, e.g. by means of a graphical user interface.The fixing is preferably effected on a touchscreen, by a pressure bar on the patient couch or by gesture control.The geometric information about the position and size and in particular also about the shape of the examination region is made available to the method.A preferred method comprises the (additional) steps:capturing a number of optical images of the examination region with an object to be examined with a camera,acquiring geometric information about the spatial position and the volume of an object to be examined (e.g. a patient) in the examination region based on the recorded images,wherein the determination of position data is carried out on the basis of the position and shape of the number of homogeneity regions and of the examination region and output of the position data, i.e. e.g. the display of the number of homogeneity regions at the position of the examination region and / or a result of a comparison of the number of homogeneity regions with the examination region or a positioning of an object taking into account the geometrical information about the object.With this embodiment, the position of the object to be examined in the three-dimensional space can be advantageously detected and the homogeneity in this space can be taken into account.The camera provides optical images of the examination region with an object to be examined. If a 3D camera was used, the volume of the object or its 3D shape can be estimated directly. If a 2D camera was used, the volume of the object can be determined, for example, from a model.The geometric information includes at least the spatial position and the volume of the object to be examined in the examination region, i.e., for example, of a foot, based on the recorded images.The display of the number of homogeneity regions at the position of the examination region and / or a result of a comparison of the number of homogeneity regions with the examination region is then carried out with attention to the geometric information about the object. It is thus determined in particular whether the object is in a homogeneity range or protrudes beyond it. The object can then be shown on a display, for example, together with the homogeneity range in a 3D representation or from a plurality of perspectives. However, it is also possible to determine whether the object (e.g. a body region) lies completely in the homogeneity region. In the case that it is not, i.e. if something of the object protrudes beyond the homogeneity range, information relating to this can be output.Correspondingly, an output of control data can be effected with attention to the geometrical information about the object. It is thus also determined here in particular whether the object is in a homogeneity range or protrudes beyond it. The optimum position of the object can then be determined and the object can be positioned automatically accordingly or data relating to its optimum position can be displayed.At least one homogeneity region is a three-dimensional region and the geometric information is likewise three-dimensional information of the object to be examined. The 3D check described above is thus possible. The geometric information was preferably determined from optical images of a 3D camera or from images of a 2D camera using a three-dimensional model of the object.A preferred device comprises in this respect:a camera, in particular a 3D camera, for recording optical images of the examination region,a geometric unit designed to receive optical images of the examination region, and to acquire geometric information about the spatial position and the volume of an object to be examined (e.g. a patient) in the examination region based on the recorded images.The device is preferably configured such that the determination of position data based on the position and shape of the number of homogeneity regions and the examination region and the output of the position data, in particular the display of the number of homogeneity regions at the position of the examination region and / or a result of a comparison of the number of homogeneity regions with the examination region or a positioning of an object takes place while observing the geometric information about the object.The examination region is preferably a body region of a person and the geometric information comprises information about the spatial position of the body region, information about the volume of the body region and / or the height profile of the body region. The homogeneity range is preferably defined not only by an area, but by a volume. Additionally or alternatively, information on patient size and weight could be provided for determining the examination region or the volume of a body region, for example by manual input of this information or from a RIS / HIS (Radiology / Hospital Information System). (image-based) information from preliminary examinations can also be used for this purpose.It is preferred that the quality information comprises information about a spatially resolved homogeneity of a main magnetic field of the MRI system in the examination region. it is determined in this case to establish a first homogeneity region whether the homogeneity at a position exceeds a predefined first limit value. It is preferred that, in order to define a second homogeneity range, it is determined whether the homogeneity at a position exceeds a predetermined second limit value, but is in particular below the first limit value.Alternatively or additionally, it is preferred that the quality information comprises information about a spatially resolved homogeneity of a gradient field of the MRI system in the examination region, wherein it is determined in order to establish a first homogeneity region whether the homogeneity at a position exceeds a predetermined first limit value. It is preferred that, in order to define a second homogeneity range, it is determined whether the homogeneity at a position exceeds a predetermined second limit value, but is in particular below the first limit value.Alternatively or additionally, it is preferred that the quality information comprises information about spatially resolved distortions in subsequently reconstructed images of the examination region. In this case, in order to define a first homogeneity range, it is determined whether a distortion at an image position exceeds a predefined first limit value. It is preferred that, in order to define a second homogeneity range, it is determined whether the distortion at an image position exceeds a predefined second limit value, but is in particular below the first limit value.Alternatively or additionally, it is preferred that the quality information comprises information about a spatially resolved quality of the image reconstruction in later reconstructed images of the examination region. In this case, in order to define a first homogeneity range, it is determined whether a quality at an image position exceeds a predefined first limit value. Preferably, in order to define a second homogeneity range, it is determined whether the quality at an image position exceeds a predefined second limit value, but is in particular below the first limit value.It is preferred that, within the scope of the display, the homogeneity range is projected onto the examination region or displayed on a display. Suitable projection apparatuses are known. The homogeneity range can be projected, for example, as a light field onto a Parson on the patient couch. It is also possible that an image of the object to be recorded is shown on a display together with the homogeneity range.Preferably, when displaying the homogeneity range, a plurality of different homogeneity ranges are displayed in different ways, in particular in different colors. For example, that homogeneity range with the best homogeneity can be displayed in a first color, e.g. green, and further homogeneity ranges with a poorer homogeneity in other colors, e.g. yellow and / or red. However, a central homogeneity region with a number of surrounding homogeneity regions can also be displayed, e.g. as a light field with dark boundaries or as a pattern of luminous boundaries. In addition, an indication can also be displayed, e.g. that the body region to be examined (e.g. the left foot) is not completely in the homogeneity range.A preferred method comprises the step of:comparing the examination zone with the homogeneity zone.In the case that it is determined during the comparison that the examination region is larger than the homogeneity region, information is output (e.g. to the operating personnel). This information preferably comprises warning information, which is output in particular by displaying a warning, e.g. as a projection onto the examination region or as a display on a display, and / or an output of an acoustic signal. Alternatively or additionally, this information comprises positioning information which indicates where the examination region should be positioned in order to lie in the homogeneity region. This allows the operator to suitably change the patient's posture prior to the beginning of the examination. The positioning information can suggest, for example, a displacement on the table or, if appropriate, a higher / lower position of an extremity, the breast, etc.It is preferable that in the case where it is determined in the comparison that the examination region is larger than the homogeneity region, based on the homogeneity region, the examination region is automatically divided into a plurality of examination regions and the method is performed again for each of these divided examination regions. A number of homogeneity ranges is thus output for each (partial) measurement range, wherein each (partial) measurement range can be positioned in a manner suitable for the examination. Alternatively or additionally, a positioning of each of these divided examination regions in the homogeneity region can also be determined. A measurement protocol is preferably automatically extended to the plurality of examination regions, in particular by duplication of the measurement steps and definition of the respective centering position. By splitting into a plurality of examination regions, two or more recordings would also be carried out, since each (partial) examination region would be recorded separately. This will correspondingly lengthen the examination time. Therefore, information about effects on the measurement time is preferably also to be output.A preferred apparatus comprises a comparison unit designed for comparing the examination region with the homogeneity region. In the case that it is determined during the comparison that the examination region is larger than the homogeneity region, information is preferably output, e.g. to the operating personnel. The comparison unit is preferably designed to automatically divide the examination region into a plurality of examination regions based on the homogeneity region when it is determined that the examination region is larger than the homogeneity region and preferably also to determine a positioning of each of these divided examination regions in the homogeneity region.The MR examination is preferably carried out within the scope of interventional imaging. There, the method according to the invention offers great advantages, since a special geometrical accuracy is particularly important in these investigations.In a preferred apparatus, the quality unit comprises a database in which the quality information is contained. This is possible since the geometry of the magnet coils is known and the magnetic field can be calculated thereby. In addition, it is possible to measure the magnetic field in advance and to store the measured values (preferably directly concerning homogeneity) as a data record. Alternatively or additionally, the quality unit comprises sensors for measuring the homogeneity of the main magnetic field and / or of a gradient field of the MRT system.The use of AI-based methods (AI: "artificial intelligence") for the method according to the invention is preferred. Artificial intelligence is based on the principle of machine-based learning, and is generally carried out using a learning-capable algorithm which has been trained accordingly. For machine-based learning, the English term "machine learning" is frequently used, wherein the principle of "deep learning" is also included here.Preferably, components of the invention are present as a "cloud service". Such a cloud service serves for processing data, in particular by means of an artificial intelligence, but can also be a service based on conventional algorithms or a service in which an evaluation by humans takes place in the background. In general, a cloud service (also referred to as a "cloud" for short hereinafter) is an IT infrastructure in which storage space or computing power and / or application software, for example, is made available via a network. The communication between the user and the cloud is effected by means of data interfaces and / or data transmission protocols. In the present case, it is particularly preferred that the cloud service provides both computing power and application software.Within the scope of a preferred method, data obtained within the scope of the invention are provided to the cloud service via the network. This includes a computing system that typically does not include the user's local computer. The method can be realized by means of a command constellation in a network. The data calculated in the cloud are later sent again via the network to the local computer of the user.The invention is explained in more detail below with reference to the attached figures on the basis of exemplary embodiments. In this case, identical components are provided with identical reference numerals in the different figures. The figures are generally not to scale. The following are shown: FIG. 1 shows a schematic representation of a magnetic resonance tomography system according to an exemplary embodiment of the invention, FIG. 2 shows a flow chart for a possible sequence of a method according to the invention, FIG. 3 shows a possible output of the method according to the invention, FIG. 4 shows a further possible output of the method according to the invention.In the following figures, only elements essential for the invention or helpful for understanding thereof are shown.FIG. 1 schematically illustrates a magnetic resonance tomography system 1. It comprises, on the one hand, the actual magnetic resonance scanner 2 with an examination space 3 or patient tunnel, in which a patient or subject is positioned on a couch 8, in the body of which the actual examination object O is located.The magnetic resonance scanner 2 is equipped in the usual manner with a basic field magnetic system 4, a gradient system 6, an RF transmitting antenna system 5 and an RF receiving antenna system 7. In the exemplary embodiment shown, the RF transmitting antenna system 5 is a whole-body coil fixedly installed in the magnetic resonance scanner 2, whereas the RF receiving antenna system 7 consists of local coils to be arranged on the patient or subject (symbolized here only by a single local coil). In principle, however, the whole-body coil can also be used as an RF receiving antenna system and the local coils as an RF transmitting antenna system, provided that these coils can be switched over in each case into different operating modes. The basic field magnetic system 4 is configured here in the usual manner such that it generates a basic magnetic field in the longitudinal direction of the patient, i.e. along the longitudinal axis of the magnetic resonance scanner 2 running in the z-direction. The gradient system 6 comprises gradient coils which can be controlled individually in the usual manner in order to be able to switch gradients in the x-, y- or z-direction independently of one another. In addition, the magnetic resonance scanner 2 contains shim coils (not shown), which can be configured in the usual manner.The magnetic resonance tomography system shown here is a whole body system with a patient tunnel into which a patient can be completely introduced. In principle, however, the invention can also be used on other magnetic resonance tomography systems, for example with a laterally open, C-shaped housing. It is only important that corresponding recordings of the examination object O can be made.The magnetic resonance tomography system 1 further comprises a central control device 13 which is used for controlling the MR system 1. This central control device 13 comprises a sequence control unit 14. Such a pulse sequence can be predefined and parameterized, for example, within a measurement protocol or control protocol. Usually, different control protocols for different measurements or measurement sessions are stored in a memory 19 and can be selected by an operator (and optionally changed if necessary) and then used for carrying out the measurement.The examination region can be defined on the basis of selected pulse sequences or on the basis of the positioning of the above-mentioned RF receiving antenna system 7.For the output of the individual RF pulses of a pulse sequence, the central control device 13 has a radio-frequency transmission device 15 which generates, amplifies and feeds the RF pulses into the RF transmission antenna system 5 via a suitable interface (not shown in detail). For controlling the gradient coils of the gradient system 6, in order to suitably switch the gradient pulses according to the predetermined pulse sequence, the control device 13 has a gradient system interface 16. The diffusion gradient pulses and spoiler gradient pulses could be applied via this gradient system interface 16. The sequence control unit 14 communicates in a suitable manner, for example by transmitting sequence control data, with the radio-frequency transmission device 15 and the gradient system interface 16 for carrying out the pulse sequence.The control device 13 also has a radio-frequency receiving device 17 (likewise communicating in a suitable manner with the sequence control unit 14) in order to receive magnetic resonance signals in a coordinated manner within the readout windows predefined by the pulse sequence by means of the RF receiving antenna system 7 and thus acquire the raw data.A reconstruction unit 18 takes over the acquired raw data here and reconstructs magnetic resonance image data therefrom. This reconstruction is also generally carried out on the basis of parameters which can be predefined in the respective measurement protocol or control protocol. This image data can then be stored, for example, in a memory 19.As suitable raw data can be acquired in detail by irradiation of RF pulses and switching gradient pulses and MR images or parameter maps can be reconstructed therefrom, it is fundamentally known to the person skilled in the art and is therefore not explained in more detail here.The control device 13 furthermore has an apparatus 12 according to the invention for planning an MR examination on this MRI system 1. This device 12 comprises the following components:A data interface 20 is designed to receive geometric information G relating to an examination region U.This information can be input, for example, by an operator.A camera K (not shown, see FIGS. 3 and 4 ), in particular a 3D camera K, for capturing optical images B of the examination region U.A geometric unit 21 is designed to receive the optical images B of the camera K, and to acquire geometric information G about the spatial position and the volume of an object to be examined in the examination region U on the basis of the recorded images B.A quality unit 22 is configured to retrieve quality information Q, e.g. from the memory 19, comprising information about homogeneity of the main magnetic field and / or the gradient fields in the examination region U and / or information about distortion correction of corrected images B of the examination region U.A homogeneity unit 23 is designed to define a number of homogeneity ranges H, H 1 in the examination range U based on a determination as to whether values of the quality information Q are in a defined value range.A position unit 24 is designed to output information for ascertaining position data based on the position and shape of the number of homogeneity regions H, H1and the examination region U and to output the position data, in particular to display the number of homogeneity regions H, H1at the position of the examination region U and / or a result of a comparison of the number of homogeneity regions H, H1with the examination region U and / or a positioning of the object O, preferably with attention to the geometric information G about the object O.A comparison unit 25 is designed to compare the examination region U with the homogeneity region H, H 1, wherein in the case that it is determined during the comparison that the examination region U is larger than the homogeneity region H, H 1, information is output. The comparison unit 25 is preferably also designed to automatically divide the examination region U into a plurality of examination regions U, U 1 when it is determined that the examination region U is larger than the homogeneity region H, H 1 based on the homogeneity region H, H 1, and preferably also to determine a positioning of each of these divided examination regions U in the homogeneity region H, H 1.The central control device 13 can be operated via a terminal 11 having an input unit 10 and a display unit 9, via which the entire magnetic resonance tomography system 1 can thus also be operated by an operator. Magnetic resonance tomography images can also be displayed on the display unit 9, and measurements can be planned and started and, in particular, control protocols can be selected and, if appropriate, modified by means of the input unit 10, if appropriate in combination with the display unit 9.The magnetic resonance tomography system 1 according to the invention and in particular the control device 13 can also have a plurality of further components, not shown in detail here but usually present on such systems, such as a network interface, in order to connect the entire system to a network and to be able to exchange raw data and / or image data or parameter maps, but also further data, such as patient-relevant data or control protocols.How suitable raw data can be acquired by irradiation of RF pulses and the generation of gradient fields and magnetic resonance tomography images can be reconstructed therefrom is fundamentally known to the person skilled in the art and is not explained in more detail here.FIG. 2 shows a flow chart for a possible sequence of a method according to the invention for planning an MR examination on an MRI system 1, as is illustrated, for example, in FIG. 1.In step I, geometric information G relating to an examination region U is provided, for example by an operator at an input terminal.In step II, a number of images B of the examination region U with an object O to be examined are recorded with a camera K and geometric information G about the spatial position and the volume of an object O to be examined in the examination region U is acquired from these images B on the basis of the recorded images B.In step III, quality information Q comprising information about homogeneity of a main magnetic field and / or gradient fields in the examination region U or information about distortion correction of corrected images B of the examination region U is provided and, based on a determination as to whether values of the quality information Q lie in a defined value range, a homogeneity range H is defined in the examination region U.In step IV, the homogeneity region H is displayed at the position of the examination region U. Alternatively, a result of a comparison of the homogeneity range H with the examination range U could also be displayed, i.e. for example whether the foot shown here is in the homogeneity range H, which it does not in this example.FIG. 3 shows a possible output of the method according to the invention (see FIG. 2 ). For example, the quality information Q here contained information about a spatially resolved homogeneity of a main magnetic field of the MRI system in the examination region U. To define a first homogeneity region H, it was then determined whether the homogeneity at a position exceeds a predefined first limit value. In addition, a second homogeneity range H 1 has also been defined, in which it has been determined whether the homogeneity at a position exceeds a predefined second limit value, but is below the first limit value.The two homogeneity regions H, H1are then projected onto the examination region U as can be seen in the figure, wherein the first (inner) homogeneity region H is represented green, for example (here by dashed lines) and the second (outer) homogeneity region H1is represented yellow, for example (here by dashed lines).FIG. 4 shows a further possible output of the method according to the invention. Here, firstly a comparison of the examination region U with the homogeneity region H was made and it was found during the comparison that the examination region U (which initially corresponded to the common surface of the two examination regions U 1, U 2 drawn in) was larger than the homogeneity region H.The original examination region U was then automatically divided into two examination regions U, U 1 and the method was carried out once again for each of these divided examination regions U, U 1. These two examination regions U, U1 can now be recorded successively, which although prolonging the examination time results in much better results.Finally, it is pointed out once again that the invention described in detail above is 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, terms such as "unit" do not exclude that the relevant components consist of a plurality of interacting sub-components, which may optionally also be spatially distributed. The term "a number" is to be read as "at least one(s)". Regardless of the grammatical sex of a certain term, individuals with male, female or other sex identity are included.References included in the specificationThis list of documents cited by the applicant has been produced in an automated manner and is only included for the better information of the reader. The list is not part of the German patent application or utility model application. The DPMA does not take any adhesion for any faults or omissions.Patent Literature citedUS 2022 / 0397623 A1

[0005] US 11540741 B2

[0006]

Claims

Method for planning an MR examination on an MRI system (1) comprising the steps of: - providing geometric information (G) relating to an examination region (U), - providing quality information (Q) comprising information about homogeneity of a main magnetic field and / or gradient fields in the examination region (U) and / or information relating to distortion correction of corrected images (B) of the examination region (U), - defining a number of homogeneity regions (H, H1) in the examination region (U) based on a determination whether values of the quality information (Q) lie in a defined value range, - determining position data based on the position and shape of the number of homogeneity regions (H, H1) and the examination region (U) and output of the position data.Method according to claim 1, wherein the examination region (U) is defined by retrieving information for examination, by positioning an MRI coil on a patient (P) or by a selection of an operator, in particular on a touchscreen, by a pressure bar on the patient bed (P) or by gesture control, and geometric information (G) on the position and size of the examination region (U) is made available to the method.Method according to one of the preceding claims, additionally comprising the steps of: - recording a number of optical images (B) of the examination region (U) with an object (O) to be examined with a camera (K), - acquiring geometric information (G) about the spatial position and the volume of an object (O) to be examined in the examination region (U) based on the recorded images (B), wherein the determination of position data based on the position and shape of the number of homogeneity regions (H, H1) and of the examination region (U) and output of the position data, in particular a display of the number of homogeneity regions (H, H1) at the position of the examination region (U) and / or a result of a comparison of the number of homogeneity regions (H, H1) with the examination region (U) and / or positioning of the object (O) takes place while observing the geometric information (G) about the object (O), preferably wherein at least one homogeneity region (H, H1) is a three-dimensional region and the geometric information (G) is likewise three-dimensional information of the object (O) to be examined, and preferably was determined from optical images (B) of a 3D camera (K) or from images (B) of a 2D camera (K) using a three-dimensional model of the object (O), preferably wherein the examination region (U) is a body region of a person and the geometric information (G) is information about the spatial position of the body region, Information about the volume of the body region and / or the height profile of the body region may be included.Method according to one of the preceding claims, wherein the quality information (Q) comprises information about - a spatially resolved homogeneity of a main magnetic field of the MRI system in the examination region (U), wherein it is determined for defining a first homogeneity region (H) whether the homogeneity at a position exceeds a predetermined first limit value, preferably wherein it is determined for defining a second homogeneity region (H1) whether the homogeneity at a position exceeds a predetermined second limit value, but in particular lies below the first limit value, and / or - a spatially resolved homogeneity of a gradient field of the MRI system (1) in the examination region (U), wherein it is determined for defining a first homogeneity region (H) whether the homogeneity at a position exceeds a predetermined first limit value, preferably wherein, in order to define a second homogeneity range (H1), it is determined whether the homogeneity at a position exceeds a predetermined second limit value, but in particular lies below the first limit value, and / or - comprises spatially resolved distortions in later reconstructed images (B) of the examination range (U), wherein, in order to define a first homogeneity range (H), it is determined whether a distortion at an image position (B) exceeds a predetermined first limit value, preferably wherein, in order to define a second homogeneity range (H1), it is determined whether the distortion at an image position (B) exceeds a predetermined second limit value, but in particular lies below the first limit value, and / or - comprises a spatially resolved quality of the image reconstruction (B) in later reconstructed images (B) of the examination range (U), wherein it is determined for defining a first homogeneity range (H) whether a quality at an image position (B) exceeds a predetermined first limit value, preferably wherein it is determined for defining a second homogeneity range (H1) whether the quality at an image position (B) exceeds a predetermined second limit value, but is in particular below the first limit value.Method according to one of the preceding claims, wherein, within the scope of a display, the homogeneity range (H, H1) is projected onto the examination region (U) or is displayed on a display, preferably wherein, when the homogeneity range (H, H1) is displayed, a plurality of different homogeneity ranges (H, H1) are displayed in different ways, in particular in different colors and / or a central homogeneity range (H) is displayed with a number of surrounding homogeneity ranges (H1).Method according to one of the preceding claims, comprising the further step of: - comparing the examination region (U) with the homogeneity region (H, H1), wherein in the case that it is determined in the comparison that the examination region (U) is larger than the homogeneity region (H, H1), information is output, preferably wherein this information comprises warning information which is output by representation of a warning and / or an output of an acoustic signal and / or comprises positioning information which indicates where the examination region (U) should be positioned so as to lie in the homogeneity region (H, H1).Method according to Claim 6, wherein, in the case that it is determined in the comparison that the examination region (U) is greater than the homogeneity region (H, H1), based on the homogeneity region (H, H1), the examination region (U) is automatically divided into a plurality of examination regions (U, U1) and the method is carried out once again for each of these divided examination regions (U, U1) and / or a positioning of each of these divided examination regions (U, U1) in the homogeneity region (H, H1) is determined, wherein a measurement protocol is preferably automatically extended to the plurality of examination regions (U, U1) and / or information about effects on the measurement time is output.Method according to one of the preceding claims, wherein the MR examination takes place within the scope of interventional imaging (B).Device (12) for planning an MR examination on an MRI system (1) comprising: - a data interface (20) designed to receive geometric information (G) relating to an examination region (U), - a quality unit (22) designed to retrieve quality information (Q) comprising information about homogeneity of a main magnetic field and / or gradient fields in the examination region (U) and / or information relating to distortion correction of corrected images (B) of the examination region (U), - a homogeneity unit (23) designed to define a number of homogeneity regions (H, H1) in the examination region (U) based on a determination whether values of the quality information (Q) are in a defined value range, a position unit (24) designed to determine position data based on the position and shape of the number of homogeneity regions (H, H1) and the examination region (U) and to output the position data, in particular to output information for displaying the number of homogeneity regions (H, H1) at the position of the examination region (U) and / or a result of a comparison of the number of homogeneity regions (H, H1) with the examination region (U), preferably with attention to geometric information (G) about the object (O).The device (12) according to claim 9, additionally comprising - a camera (K), in particular a 3D camera (K), for recording optical images (B) of the examination region (U), - a geometry unit (21) designed to receive optical images (B) of the examination region (U), and to acquire geometric information (G) about the spatial position and the volume of an object to be examined in the examination region (U) based on the recorded images (B), wherein the device (12) is designed such that the determination of position data based on the position and shape of the number of homogeneity regions (H, H1) and the examination region (U) and output of the position data, in particular a display of the number of homogeneity regions (H, H1) is effected at the position of the examination region (U) and / or a result of a comparison of the number of homogeneity regions (H, H1) with the examination region (U) and / or a positioning of the object (O) taking into account the geometric information (G) about the object (O).The apparatus (12) according to claim 9 or 10, wherein the quality unit (22) comprises a database in which the quality information (Q) is contained and / or comprises sensors for measuring the homogeneity of the main magnetic field and / or a gradient field of the MRI system (1).The device (12) according to any one of claims 9 to 11, comprising a comparison unit (25) configured to compare the examination region (U) with the homogeneity region (H, H1), wherein, in the case that it is determined in the comparison that the examination region (U) is larger than the homogeneity region (H, H1), information is output, preferably wherein the comparison unit (25) is configured, when it is determined that the examination region (U) is larger than the homogeneity region (H, H1), to automatically divide the examination region (U) into a plurality of examination regions (U, U1) based on the homogeneity region (H, H1) and preferably also to determine a positioning of each of these divided examination regions (U) in the homogeneity region (H, H1).MRI system (1) comprising an apparatus (12) according to one of claims 9 to 12 and / or configured to carry out a method according to the invention according to one of claims 1 to 8.Computer program product comprising instructions which, when the program is executed by a computer, cause the computer to carry out the steps of the method according to Claims 1 to 8, wherein the provision, acquisition or recording of information comprises reception of this information, in particular associated with a previous output of control commands.Computer-readable storage medium (19) comprising instructions which, when executed by a computer, cause the computer to carry out the steps of the method according to Claims 1 to 8, wherein the provision, acquisition or recording of information comprises a reception of this information, in particular associated with a previous output of control commands.

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