Preparation of MR elastography with MR elastography device

Abstract

This invention relates to a method for preparing for MR elastography of the liver according to the following steps: generating an image record of the subject to be examined; determining the position of the liver based on the image record; providing information regarding the target position of a vibration generator based on the position of the liver; positioning the vibration generator at the subject to be examined based on the information regarding the target position; introducing the subject to be examined with the vibration generator into the patient receiving area of ​​a magnetic resonance imaging device; detecting summary MR image data of the subject to be examined; and selecting an examination area for a cross-section covering at least one subregion of the liver based on the summary MR image data to record MRE image data.

Description

Technical Field

[0001] The present invention relates to a method and an MR elastography apparatus for preparing for MR elastography of the liver of an examination subject. Background Technology

[0002] In magnetic resonance imaging (MRI) equipment, the subject of examination, particularly the patient's body, is typically subjected to a relatively high main magnetic field, such as 1.5 or 3 Tesla, by means of a main magnet. During MRI, gradient pulses are emitted by means of gradient coil units. Additionally, high-frequency radio frequency (HF) pulses, particularly excitation pulses, are subsequently transmitted via a radio frequency (RF) antenna unit using a suitable antenna device. This causes the nuclear spins of atoms resonantly excited by the HF pulses to flip by a flip angle defined by the magnetic field lines of the main magnetic field. Upon nuclear spin relaxation, a radio frequency signal, the so-called magnetic resonance signal (MR signal), is emitted, which is received by means of a suitable RF antenna and then further processed. Finally, the desired image data can be reconstructed from the raw data thus acquired. Therefore, for a specific measurement, a specific MRI control sequence (MR control sequence) should be transmitted, which consists of a series of RF pulses, such as excitation pulses and refocusing pulses, and gradient pulses to be transmitted in coordination with this on different gradient axes along different spatial directions. A reading window is set in a time-matched manner, the reading window having a preset time period during which induced magnetic resonance signals are detected.

[0003] In MR elastography (MRE), the phase of the magnetic resonance signal changes due to mechanical waves acting on the examined object. The scale of this change depends on the tissue's displacement due to the mechanical waves (i.e., movement from a resting position). Therefore, specific mechanical parameters of the tissue, such as information about its elasticity, can be derived from the MR phase image, that is, an image showing the phase of the nuclear magnetization. Thus, MRE is a non-invasive method for quantifying the elasticity and stiffness of tissues. For MRE, a vibration generator is additionally required compared to conventional MRI equipment to generate mechanical waves, particularly in the examination area of ​​the examined object. The vibration generator can, for example, comprise a flexible diaphragm excited to vibration by means of acoustic energy, as described in US7034534B2. The vibration generator can also be configured as a gravity vibration generator, as described, for example, in US20230305090A1.

[0004] Generating, acquiring, and / or detecting MRE image data of the examination area includes transmitting mechanical waves to the examination area according to a vibration generator and performing MR imaging in time-coordinated with a magnetic resonance device. The MR imaging includes generating magnetic resonance signals in the examination area, acquiring corresponding raw data, and reconstructing them into image data, wherein such image data is referred to as MRE image data.

[0005] MRE (Mass Reaction) of the liver is particularly important for the non-invasive diagnosis of chronic liver disease, fibrosis, and inflammation. The liver typically has its maximum spatial extension approximately parallel to the transverse axis of the subject being examined. The areas of interest during MRE, especially the areas of the liver, are such that MRE image data can be acquired from these areas, the examination areas, during the MRE process. The examination areas during liver MRE imaging are typically covered by transverse sections, which are located based on the liver and also on the position and anatomy of surrounding organs. Furthermore, it is crucial to ensure that the vibration generator is positioned on the body surface of the subject in such a way that the mechanical waves generated by the vibration generator penetrate the spatial extension of the examination area, especially the transverse sections. Therefore, for MRE, especially for liver MRE, coordinated and precise positioning of the transverse sections used for MR imaging and the vibration generator on the body surface is important. Summary of the Invention

[0006] The objective of this invention is to describe a particularly simple and robust method for preparing and performing MRE (myografting) of the liver using an MR elastography device. This objective is achieved through this invention. Advantageous designs are described below.

[0007] According to the present invention, a method for preparing for MR elastography of a liver of a subject using an MR elastography apparatus, the MR elastography apparatus comprising a vibration generator and a magnetic resonance imaging (MRI) device having a patient accommodating area, the method comprising the following steps:

[0008] - Generate photographic records of at least a portion of the object being inspected.

[0009] -The location of the liver was determined based on the photographic records.

[0010] - Information about the target location of the vibration generator is provided based on the location of the liver.

[0011] - Set the vibration generator to the object being inspected based on the information regarding the target location.

[0012] - Introduce the examination object with a vibration generator into the patient accommodation area.

[0013] - Detect summary MR image data of the object being examined.

[0014] - Based on the summary MR image data, the examination area for cross-sections covering at least one sub-region of the liver is selected to record MRE image data.

[0015] During the filming process, at least the upper body of the subject is typically examined. The filming process typically examines the body surface of the subject.

[0016] Determining the location of the liver typically involves analyzing the body surface imaged on a photographic record. The location of the liver can be extracted and / or estimated and / or approximated based on externally identifiable features such as the location of joints, shoulders, arms, and / or neck.

[0017] Providing information regarding the target location of the vibration generator based on the location of the liver typically includes determining the target location of the vibration generator. The target location of the vibration generator preferably corresponds to an optimal position of the vibration generator on the body surface of the subject being examined. The target location of the vibration generator is typically positioned laterally in the upper body, particularly laterally in the thoracic cavity, wherein a cross-section of the liver includes a section region with the target location of the vibration generator. Information regarding the target location of the vibration generator may include the target location of the vibration generator itself. Information regarding the target location of the vibration generator may include the location of the liver, particularly the midpoint of the liver, for example, in the longitudinal direction. Based on the location of the liver, i.e., based on this information, the true target location of the vibration generator can be derived. In particular, the vibration generator can be positioned relative to the subject being examined based on the location of the liver.

[0018] Setting a vibration generator to the object of inspection based on information regarding the target location typically involves placing the vibration generator at the target location. Setting the vibration generator to the object of inspection may include extracting the target location from the information regarding the target location, provided that the information regarding the target location indirectly includes that target location. Setting the vibration generator to the object of inspection typically involves securing the vibration generator to the body surface of the object of inspection, for example, by means of a strap. The vibration generator is preferably configured such that it has direct contact with the skin of the object of inspection.

[0019] Summary MR image data is typically acquired using magnetic resonance imaging (MRI) equipment. Summary MR image data typically comprises MR image data in a coronal orientation. The spatial resolution of summary MR image data is typically smaller than that of diagnostic image data, such as MRE image data.

[0020] Selecting an inspection area typically involves selecting cross-sections. The inspection area is preferably subdivided into cross-sections. Gaps may exist between adjacent cross-sections within the inspection area. Adjacent cross-sections within the inspection area may be directly adjacent to each other.

[0021] The method steps in the method for preparing MR elastography according to the invention are therefore preferably performed before MRE is performed. Specifically, the subject and vibration generator are positioned to record MRE image data, and the examination area is selected accordingly and individually for the subject. In particular, the method according to the invention enables automatic pre-setting of the correct position of the vibration generator and automatic selection of the examination area, thus achieving standardized preparation and performance of liver MRE. Furthermore, typically, the vibration generator is manually positioned on the subject only based on specific pre-set information regarding the target position of the vibration generator. This achieves a simple and robustly executable method for preparing MRE and reduces the probability of mispositioning of the vibration generator and / or the examination area, making MRE preparation particularly time-efficient. In particular, the positions of the vibration generator and the examination area can therefore be well coordinated with each other and individually coordinated with the orientation of the liver of the subject. The method can be performed particularly simply and independently of the experience of the medical personnel.

[0022] One implementation of the method proposes that the selection of the inspection area considers at least one of the following characteristics:

[0023] - Exclude lungs from the examination area.

[0024] - A cross-section covering the liver with the maximum spatial extension parallel to the transverse axis of the object being examined.

[0025] A cross-section of the liver with its maximum spatial extension parallel to the transverse axis of the object being examined typically includes the liver's maximum transverse extension. The liver is typically located distal to the lungs, particularly inferiorly.

[0026] The examination area is preferably a square region at the distal end of the lung. The examination area is preferably selected such that the lung is outside the examination area. This is advantageous for the recording of MR signals, especially MRE image data, because air within the lung, and thus missing tissue, impairs the quality of the MR signal due to magnetic susceptibility. Excluding the lung from the examination area reduces artifacts in the MRE image data. Additionally, the position of the cross-section includes information regarding the elasticity of the entire organ.

[0027] One implementation of the method proposes selecting inspection areas based on markers.

[0028] The markers preferably include at least one of the following segments and / or locations within the liver: hepatic fornix, right lobe, left lobe, lateral segment, quadrate lobe, caudate lobe, anterior segment, and posterior segment. Markers may also include features of other organs, such as the location and / or orientation of the lungs. Alternatively and / or additionally, liver segmentation may be considered when selecting the examination region, relative to the markers. Selecting the examination region may include segmenting the summary MR image data of the liver, wherein segmented liver segments may be considered when selecting the examination region. This selection of the examination region can be performed by an algorithm in a well-automated, robust, and repeatable manner.

[0029] One embodiment of the method proposes selecting an examination region using a trained first function. This embodiment typically includes providing a trained first function. The trained first function may, for example, include a neural network and / or a U-network and / or a convolutional neural network. The trained first function may be configured to identify the location of markers and / or organs and / or positioned vibration generators in summary MR image data and determine the optimal location and spatial extension of the examination region and / or the direction, orientation, thickness, and / or number of transverse sections. The trained first function is preferably applied to the summary MR image data. The trained first function may optionally be configured to take into account the imaging recording. The examination region and / or transverse sections are preferably output as the result of the trained first function according to the embodiment. This selection of the examination region can be well automated and individualized for each examination subject.

[0030] One implementation of the method additionally includes providing a patient model, wherein the location of the liver is determined in consideration of the patient model.

[0031] A patient model typically includes at least one association between the location and / or orientation and / or spatial extension of the liver and the photographic record of the subject, particularly their body surface. The patient model may also include the location and / or orientation and / or spatial extension of other organs. In particular, the patient model may include an association between external features, particularly those externally identifiable on the photographic record, such as the location of the neck, shoulders, hips, and / or hands, and the location and / or orientation and / or spatial extension of the liver. The patient model can be generated and / or provided using a trained third function. In particular, artificial neural networks can be used to generate the patient model. This determination of the liver's location takes into account the individualized characteristics of the subject, particularly based on the photographic record, and can be performed well, automatically, robustly, and repeatably by an algorithm.

[0032] One implementation of the method additionally includes providing a trained second function.

[0033] The location of the liver is determined using a trained second function. This trained second function typically involves the correlation between the liver's location and / or orientation and / or spatial extension and the imaging records of the subject being examined. In particular, the trained second function can be performed in combination with and / or integrated with a patient model. The trained second function can, for example, include neural networks and / or U-networks and / or convolutional neural networks. This determination of the liver's location takes into account the individualized characteristics of the subject being examined, especially based on imaging records, and can be performed well, automatically, and accurately by an algorithm.

[0034] One embodiment of the method proposes that the magnetic resonance imaging (MRI) device includes a marking device and a patient support device for supporting the positioning of the subject of examination within the patient accommodation area.

[0035] During the recording, the subject of the examination was at least partially positioned outside the patient accommodation area on the patient support device.

[0036] It also provides information on the target location of the vibration generator, including visualizing the location of the liver and / or the target location of the vibration generator by marking the location of the liver and / or the target location of the vibration generator on the body surface of the subject of examination using a marking device.

[0037] The marking device may include a laser. The marking device may be configured to optically mark the location of the liver on a body surface, particularly by means of a photon beam. The marking device may be configured to mark the midpoint of the liver and / or the center of the liver along the longitudinal axis of the body being examined. The patient support device may be configured to move the subject along the longitudinal axis of the MRI machine during the marking of the liver's location on the body surface. Especially when the marking device is typically used during isocentric positioning of the subject, the marking device may be configured solely for vertical marking. The patient support device may also perform horizontal movement of the subject along the longitudinal axis of the MRI machine in the horizontal direction, thus working in conjunction with the marking device to mark the location of the liver.

[0038] The vertical axis coordinate of the liver's location typically corresponds to the vertical axis coordinate of the target location of the vibration generator. The horizontal axis coordinate of the target location of the vibration generator is typically determined by the lateral extension of the thoracic cavity. Preferably, the target location of the vibration generator is laterally positioned in the thoracic cavity at the height of the liver, typically on the side of the thoracic cavity facing the right lobe of the liver. The target location of the vibration generator can be clearly identified by medical personnel when marking the location of the liver, allowing the vibration generator to be clearly positioned at its target location. The described embodiment of the method preferably uses a marking device, typically available for other purposes at a magnetic resonance imaging device, to mark the location of the liver to provide information regarding the target location of the vibration generator.

[0039] One embodiment of the method proposes generating an image recording using a 3D camera. The image recording captured by the 3D camera has a spatial stereoscopic effect and can achieve a defined depth map. Therefore, the 3D camera can detect surfaces stereoscopically, allowing for particularly precise determination of the body surface of the subject being examined. Based on this image recording, the location of the liver can be determined with particularly high precision according to the present invention.

[0040] One embodiment of the method proposes that time-resolved recordings be generated. In particular, a camera configured as a video camera, preferably a 3D camera configured as a video camera, can achieve time-resolved recording of the object under inspection. According to the embodiment, the vibration generator is positioned at the object under inspection based on information regarding the target location, preferably at least partially simultaneously with the time-resolved recording of the object under inspection. This enables continuous monitoring and comparison of the vibration generator's current position with the target position provided by the vibration generator during its positioning at the target location. This reduces the probability of incorrect positioning of the vibration generator in the method according to the invention.

[0041] One embodiment of the method proposes that the magnetic resonance device has a display unit.

[0042] It also provides information on the target location of the vibration generator, including displaying the captured footage and the target location of the vibration generator on the display unit.

[0043] The display unit typically includes a monitor and / or display. The image recording is preferably shown on the display unit immediately upon its generation and / or with a delay of less than 5 seconds. The image recording is preferably detected in time resolution and displayed continuously on the display unit. The target position of the vibration generator is preferably shown superimposed on the image recording. Preferably, information regarding the target position of the vibration generator is provided during the positioning of the subject on a patient support device and introduction into the patient reception area of ​​the MRI machine via said patient support device, typically without active movement of the subject. This process of setting the vibration generator at the preset target position is achieved by visually displaying the vibration generator and the preset target position for the vibration generator on the display unit. This embodiment provides continuous feedback on the position of the vibration generator to the medical personnel setting the vibration generator on the subject, thereby avoiding the need to reposition the vibration generator and / or acquire erroneous MRE image data.

[0044] One embodiment of the method proposes that the captured recording includes visualization in at least two viewing directions, particularly two perspectives. The display unit can be segmented and / or subdivided, allowing the target location for the vibration generator to be shown in both perspectives and better supporting navigation for locating the vibration generator. In particular, the display unit can visualize a front view and a lateral view of the target location of the object under inspection and the vibration generator. This enables particularly precise positioning of the vibration generator.

[0045] One implementation of the method additionally includes

[0046] - Comparative results were determined by analyzing summary MR image data in terms of the position of the vibration generator relative to the liver, and

[0047] - Output instructions on repositioning the vibration generator based on the comparison results.

[0048] According to the present invention, summary MR image data is recorded after the vibration generator is positioned at its target location. The vibration generator is preferably designed to emit MR signals that can be identified in the image data, particularly in the summary MR image data, at least for the algorithm and / or visually. Analyzing the summary MR image data regarding the position of the vibration generator relative to the liver typically involves determining the position of the vibration generator and the position of the liver within the summary MR image data. In particular, an updated target position of the vibration generator can be determined based on the position of the liver extracted from the summary MR image data, and said updated target position can be compared with the position of the vibration generator. In case of deviation, particularly when the deviation is greater than a threshold, indications for repositioning can include a request to reposition the vibration generator. This enables the vibration generator to be repositioned before performing the actual MRE, particularly before recording the MRE image data.

[0049] One implementation of the method is proposed,

[0050] - Determining the comparison results includes determining the difference between the position of the vibration generator and the position of the liver in the longitudinal direction, and

[0051] - The output indication includes a length specification for moving the vibration generator in the longitudinal direction.

[0052] The comparison result, according to the described embodiment, includes the difference in the longitudinal position of the vibration generator and the liver. The output indication typically includes providing the difference, and optionally provides the difference based on a threshold.

[0053] Instructions for repositioning can include a description of the offset to indicate how much the vibration generator should be moved in the longitudinal direction. Medical personnel can then reposition the vibration generator according to the described offset. This achieves particularly precise repositioning.

[0054] One embodiment of the method additionally includes performing MR elastography using an MR elastography device, which includes recording MRE image data of the examined area and temporally manipulating a vibration generator. For this purpose, the MRI device is typically manipulated according to an MR control sequence, and synchronously, the examined area is subjected to mechanical waves and / or vibrations generated by the vibration generator. The vibration generator, positioned according to the invention, achieves particularly uniform penetration into the selected examined area, which covers important regions of the liver. This recorded MRE image data is particularly convincing for diagnosis.

[0055] Furthermore, the present invention is based on an MR elastography device, the MR elastography device comprising:

[0056] - A vibration generator, configured to produce mechanical waves.

[0057] - Magnetic resonance imaging (MRI) equipment, which is configured to detect summary MR image data and MRE image data.

[0058] - A camera, whose components are used to generate photographic records.

[0059] - Determining unit, constituting a method for determining the location of the liver based on imaging records, and

[0060] - A unit is provided that constitutes information regarding the target location of the vibration generator, particularly based on the location of the liver.

[0061] -Selection unit, configured to select the inspection area.

[0062] Therefore, the MR elastography apparatus according to the present invention is configured to perform the method according to the present invention.

[0063] The determining unit, providing unit, and selecting unit may be constituted as part of the control unit and / or together referred to as the control unit. The determining unit, providing unit, and selecting unit may be constituted at least partially independently of each other and / or independently of the control unit.

[0064] A control unit typically has input terminals, a processor unit, and output terminals.

[0065] The determining unit, providing unit, and / or selecting unit typically have an input terminal, a processor unit, and an output terminal, and / or may have a connection to the input terminal, processor unit, and / or output terminal of the control unit.

[0066] Therefore, the determining unit can be provided with the captured image and the liver position output by the determining unit. The providing unit is preferably configured to obtain and provide information regarding the target position of the vibration generator based on the liver position. The selecting unit is typically configured to provide selected examination areas. Additional functions, algorithms, or parameters required in the method can be provided to the control unit and / or the determining unit and / or the selecting unit and / or the providing unit via input terminals.

[0067] The control unit and / or determining unit and / or selecting unit and / or providing unit can be integrated into the MR elastography device. Alternatively, the control unit and / or determining unit and / or selecting unit and / or providing unit can be installed independently of the MR elastography device. The control unit and / or determining unit and / or selecting unit and / or providing unit can be connected to the MR elastography device.

[0068] The embodiments of the MR elastography apparatus according to the present invention are similar in configuration to the embodiments of the method according to the present invention. The MR elastography apparatus may have additional control components, which are necessary and / or advantageous for executing the method according to the present invention. The MR elastography apparatus may also be configured to transmit and / or receive and / or process control signals in order to execute the method according to the present invention. A computer program and additional software may be stored in the memory unit of the control unit, by means of which the processor unit of the control unit automatically controls and / or executes the method flow according to the present invention.

[0069] The computer program product according to the invention can be directly loaded into the memory unit of a programmable control unit and has a program code structure so that when the computer program product is executed in the control unit, the method according to the invention is performed. This allows for rapid, consistent, repeatable, and robust execution of the method according to the invention. The computer program product is configured such that it can execute the method steps according to the invention by means of the control unit. The control unit must have prerequisites such as, for example, a corresponding working memory, a corresponding graphics card, or a corresponding logic unit, to enable efficient execution of the corresponding method steps. The computer program product is stored, for example, on an electronically readable medium or on a network or server, from which it can be loaded into the processor of a local control unit, which can be directly connected to or constitute part of the MR elastography device. Furthermore, the 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, when the data carrier is used, the control information executes the method according to the invention in the control unit of the MR elastography device. Examples of electronically readable data carriers are DVDs, magnetic tapes, or USB sticks, on which electronically readable control information, especially software, is stored. When the control information (software) is read by the data carrier and stored in the control unit of the MR elastography device, all embodiments of the above method according to the present invention can be executed.

[0070] Furthermore, the present invention is based on an electronically readable data carrier on which a program is stored, the program being configured to execute the method according to the present invention.

[0071] The advantages of the MR elastography apparatus according to the invention, the computer program product according to the invention, and the electronically readable data carrier according to the invention substantially correspond to the advantages of the method according to the invention as detailed above. The features, advantages, or alternative embodiments mentioned herein can also be applied to other claimed subjects, and vice versa. Attached Figure Description

[0072] Further advantages, features and details of the invention will become apparent from the embodiments described below and from the accompanying drawings.

[0073] The attached diagram shows:

[0074] Figure 1 A schematic diagram of an MR elastography apparatus according to the present invention is shown.

[0075] Figure 2 A flowchart illustrating a first embodiment of the method according to the present invention is shown.

[0076] Figure 3A flowchart illustrating a second embodiment of the method according to the present invention is shown.

[0077] Figure 4 A flowchart illustrating a third embodiment of the method according to the present invention, and

[0078] Figure 5 A schematic diagram showing the relative positions of the examination areas, including the transverse sections. Detailed Implementation

[0079] Figure 1 A schematic diagram of an MR elastography apparatus according to the present invention is shown. The MR elastography apparatus includes a magnetic resonance device 33. According to the embodiment described, the magnetic resonance device 33 includes a hollow cylindrical detector unit 31 that surrounds, in particular concentrically surrounds, a cylindrical patient receiving area 40. The cylindrical patient receiving area 40 is configured for recording an examination subject 17. The examination subject 17 can be pushed into the patient receiving area 40 by means of a patient support device 16 of the magnetic resonance device 33. The patient support device 16 is configured to introduce the examination subject 17, particularly an examination subject 17 having a vibration generator 21, into the patient receiving area 40. The detector unit 31 typically includes a main magnet (not shown in detail), a gradient coil unit (not shown in detail), and / or a radio frequency antenna unit (not shown in detail) configured to emit excitation pulses.

[0080] To control the detector unit 31, the magnetic resonance device 33 has a control unit 32. The control unit 32 centrally controls the magnetic resonance device 33, such as executing an MR control sequence to generate and detect MR signals. Furthermore, the control unit 32 includes a reconstruction unit (not shown in detail) for reconstructing image data from the MR signals or raw data. Therefore, depending on the operation of the vibration generator 21 and the detector unit 31, the magnetic resonance device 33 is configured to detect summary MR image data and MRE image data. The control unit 32 may have a display (not shown in detail) and input units (not shown in detail). Furthermore, the control unit 32 may be configured to evaluate the MRE image data.

[0081] The MR elastography apparatus additionally includes a vibration generator 21 configured to generate mechanical waves. The vibration generator 21 is typically flexibly positionable and / or fixed to the examination subject 17 and / or the patient support device 16. The vibration generator 21 can be configured as a passive vibration generator. In the illustrated embodiment, the vibration generator 21 is manipulated and / or activated by a vibration generator unit 30, for example, including a stepper motor. For this purpose, the vibration generator 21 is connected to the vibration generator unit 30 via a connector 28. The connector 28 can be configured as a flexible rotating lead.

[0082] The MR elastography apparatus additionally includes a camera 18 configured to generate photographic recordings. In the illustrated case, camera 18 is positioned at the longitudinal end of the housing of detector unit 31. Camera 18 can also be freely positioned in space. Camera 18 typically has a detection area to be pointed toward the object 17 being inspected, within which camera 18 can record photographic recordings. Camera 18 can be configured as a video camera to record time-resolved photographic recordings. Camera 18 can alternatively and / or additionally be configured as a 3D camera, i.e., configured for three-dimensional inspection of the body surface of the object 17 being inspected.

[0083] The magnetic resonance imaging (MRI) device 33 optionally includes a marking device 19 in the illustrated case. The marking device 19 typically includes a laser, which is particularly helpful in positioning the subject 17 for examination. Thus, the subject 17 can be positioned such that the area to be examined on the subject 17 is marked by the marking device 19 and subsequently automatically guided into an optimal position within the patient receiving area 40, while being at least partially positioned outside the patient receiving area 40. According to one embodiment of the invention, the marking device 19 can be used to visualize the position of the liver 12 by marking the position 20 of the liver 12 on the body surface of the subject 17 in the process of providing information regarding the target position of the vibration generator 21.

[0084] The magnetic resonance imaging (MRI) device 33 optionally includes a display unit 38 in the illustrated configuration. The display unit 38 is configured to display the imaging record of the subject 17 and simultaneously visualize the target position 22 of the vibration generator 21, for example, by overlay. In particular, displaying the imaging record of the subject 17 may also include marking the position 20' of the liver 12 on the imaging record. The display unit 38 can display in at least one first viewing direction 23, particularly for a first orientation. Additionally, the display unit 38 can optionally visualize the display in at least one second viewing direction 23', i.e., a second orientation. The second viewing direction 23' is preferably configured perpendicular to the first viewing direction 23.

[0085] The illustrated magnetic resonance imaging (MRI) device 33 may obviously include additional components typically found in MRI devices 33. Furthermore, the general operation of the MRI device 33 is known to those skilled in the art, making a detailed description of the additional components unnecessary.

[0086] The MR elastography device includes a determination unit 34 configured to determine the location of the liver 12 based on the imaging record and a provisioning unit 35 configured to provide information on the target location of the vibration generator 21.

[0087] Furthermore, the MR elastography device includes a selection unit 36 ​​for selecting the examination area. The determining unit 34, the providing unit 35, and the selection unit 36 ​​can be configured as part of the control unit 32 of the magnetic resonance device 33.

[0088] Therefore, the MR elastography device is configured to perform the method according to the invention, wherein only the method step 140 of setting the vibration generator 21 at the object to be examined 17 is manually performed based on information regarding the target location.

[0089] Furthermore, the control unit 24, and particularly the determining unit 34, providing unit 35, and selecting unit 36, have computer programs and / or software that can be directly loaded into a memory unit (not shown in detail) of the control unit 24. These computer programs and / or software have a program structure to execute the method according to the invention when executed in the control unit 24. The control unit 24 has a processor (not shown in detail) designed to execute the computer programs and / or software. Alternatively, the computer programs and / or software may also be stored on an electronically readable data carrier 14, which is separately configured from the control unit 24, wherein data access to the electronically readable data carrier 14 by the control unit 24 can be performed via a data network. Therefore, the MR elastography device, together with the control unit 24, is designed to execute the method according to the invention.

[0090] The method according to the invention can also exist in the form of a computer program product, which implements the method on the control unit 24 when the method is executed on the control unit 24. Similarly, an electronically readable data carrier 14 can exist together with electronically readable control information stored thereon, the control information including at least one such computer program product and designed to execute the method in the control unit 24 of the MR elastography device when the data carrier 14 is used.

[0091] Figure 2 A flowchart illustrating a first embodiment of the method for preparing MR elastography of a liver 12 of an examination subject using an MR elastography device according to the present invention is shown, wherein the MR elastography device includes a vibration generator 21 and a magnetic resonance device 33 having a patient accommodating area 40.

[0092] The method begins with method step 110, which generates an image recording of at least a portion of the object 17 to be examined. Method step 110 is typically performed using a camera 18. In method step 120, the location of the liver 12 is determined based on the image recording. Method step 120 is typically performed using a determination unit 34. Method step 130 includes providing information regarding the target location of the vibration generator 21 based on the location of the liver 12. Method step 130 is typically performed using a providing unit 35.

[0093] In method step 140, the vibration generator 21 is positioned at the examination subject 17 based on information regarding the target location. Method step 140 is typically performed manually by a medical professional. Method step 150 involves introducing the examination subject 17, equipped with the vibration generator 21, into the patient receiving area 40. Method step 150 is typically performed using a patient support device 16. In method step 160, summary MR image data of the examination subject 17 is detected. Method step 160 is typically performed using a magnetic resonance imaging device 33 and, in particular, a detector unit 31.

[0094] In the following method step 170, an examination region 11 of a transverse section 10 covering at least one subregion of the liver 12 is selected based on the summary MR image data to record MRE image data. Method step 170 is typically performed with reference to biomarkers. Method step 170 is typically performed by means of a selection unit 36.

[0095] Figure 3 A flowchart illustrating a second embodiment of the method according to the present invention is shown. The second embodiment is related to... Figure 2 The difference in the first embodiment shown in particular lies in the additional method steps 121, 131, 132, and 171, which can also be performed independently of each other.

[0096] Method step 121 includes providing a patient model, which is considered in method step 120 when determining the location of the liver 12. Method step 171 includes providing a trained function, which is considered in method step 170 when selecting the examination region 11.

[0097] Following method step 130, providing information 21 regarding the target location of the vibration generator based on the location of the liver 12 can be performed according to method steps 131 and / or 132. Method step 131 requires a marking device 19 and a patient support device 16 for supporting the examination subject 17 positioned within the patient receiving area 40 and, during the recording process, the examination subject 17 is at least partially positioned outside the patient receiving area 40 on the patient support device 16. Method step 131 proposes visualizing the location of the liver 12 by marking 20 on the body surface of the examination subject 17 using the marking device 19. Method step 132 requires a display unit 38 on which the recording is displayed according to method step 132 and the target location 22 of the vibration generator 21 is shown.

[0098] Figure 4 A flowchart illustrating a third embodiment of the method according to the present invention is shown. The third embodiment is related to... Figure 2 The difference in the first embodiment shown is particularly in the additional method steps 180, 182, and 190, wherein at least method step 190 can also be performed independently of the other two method steps. Method step 180 proposes analyzing the summary MR image data generated in method step 160 in terms of the position of the vibration generator 21 relative to the liver 12, wherein a comparison result is determined. This can be done, for example, by determining the difference between the position of the vibration generator 21 in the longitudinal direction and the position of the liver 12 in the summary MR image data. Optionally, in method step 182, an instruction for repositioning the vibration generator 21 can be output based on the comparison result, particularly including an instruction specifying the length of movement of the vibration generator 21 in the longitudinal direction. Subsequently, in method step 190, MR elastography is performed, wherein MRE image data of the examination area 11 is recorded by means of an MR elastography device and the vibration generator 21 is manipulated temporally and in a coordinated manner.

[0099] Figure 5 A schematic diagram showing the relative positions of the examination area 11, including the transverse section 10, of the subject 17 is shown. The examination area 11 is selected such that the lungs 13 are outside the examination area 11 and are therefore not covered by the transverse section 10. Conversely, the liver 12 of the subject 17 is covered by the examination area 11 at a position in the longitudinal direction of the subject 17, where the liver 12 has the maximum spatial extension parallel to the transverse axis of the subject 17. Furthermore, a target position 22 for the vibration generator 21 is marked in the figure.

[0100] Although the details of the invention have been described and illustrated with reference to preferred embodiments, the invention is not limited to the disclosed examples, and other variations can be derived by those skilled in the art without departing from the scope of protection of the invention. Regardless of the grammatical gender of a particular term, it also includes persons of either male or female gender.

Claims

1. A method for preparing for MR elastography of the liver of a subject using an MR elastography device, the MR elastography device comprising a vibration generator and a magnetic resonance imaging (MRI) device having a patient accommodating area, the method comprising the following steps: - Provide a patient model that includes a correlation between photographic records of externally identifiable features and the location and / or orientation and / or spatial extent of the liver. - Generate photographic records of at least a portion of the object being inspected. - Determine the location of the liver based on the photographic records and taking into account the patient model. - Information regarding the target location of the vibration generator is provided based on the location of the liver. - Based on information regarding the target location, the vibration generator is positioned at the object being inspected. - Introduce the examination object, which has the vibration generator, into the patient accommodation area. - Detect summary MR image data of the object under inspection. - Based on the summary MR image data, an examination area for cross-sectional tomography covering at least one sub-region of the liver is selected to record MRE image data.

2. The method according to claim 1, The selection of the inspection area takes into account at least one of the following characteristics: - Exclude the lungs from the area being examined. - A cross-section covering the liver with the maximum spatial extension parallel to the transverse axis of the object being examined.

3. The method according to any one of the preceding claims, The inspection area is selected based on the markers.

4. The method according to any one of the preceding claims, The inspection region is selected using a first function that has been trained.

5. The method according to any one of the preceding claims, The method additionally includes providing a trained second function. The location of the liver is determined using the trained second function.

6. The method according to any one of the preceding claims, The magnetic resonance imaging (MRI) device includes a marking device and a patient support device for positioning the object being examined within the patient accommodation area. During the recording, the object of examination is at least partially positioned outside the patient receiving area on the patient support device. And providing information regarding the target location of the vibration generator includes visualizing the location of the liver and / or the target location of the vibration generator by marking the location of the liver and / or the target location of the vibration generator on the body surface of the subject of examination using a marking device.

7. The method according to any one of the preceding claims, The shooting record is generated using a 3D camera.

8. The method according to any one of the preceding claims, The shooting record is generated in a time-resolved manner.

9. The method according to any one of the preceding claims, The magnetic resonance device described above has a display unit. Information regarding the target location of the vibration generator is provided, including displaying the captured footage and the target location of the vibration generator on the display unit.

10. The method according to claim 9, The photographic record shown includes visualization in at least two viewing directions.

11. The method according to any one of the preceding claims, The method additionally includes - The comparison results were determined by analyzing the summary MR image data with respect to the position of the vibration generator relative to the liver, and - Based on the comparison results, an instruction is output regarding the repositioning of the vibration generator.

12. The method according to claim 11, in - Determining the comparison result includes determining the difference between the position of the vibration generator and the position of the liver in the longitudinal direction, and - The output of the indication includes a length specification for moving the vibration generator in the longitudinal direction.

13. The method according to any one of the preceding claims, The method additionally includes performing MR elastography using an MR elastography device, which includes recording MRE image data of the examined area and temporally manipulating the vibration generator.

14. An MR elastography device, the MR elastography device comprising: A vibration generator, which is configured to generate mechanical waves, Magnetic resonance imaging (MRI) devices are configured to detect summary MR and MRE image data. A camera, whose components are used to generate photographic records, A determining unit, configured to determine the location of the liver based on the captured images, and A providing unit, configured to provide information regarding the target location of the vibration generator, The selection unit is configured to select the inspection area. The MR elastography device thus constitutes a method for performing any of the preceding claims.

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