Transmitting desired image impressions between different magnetic resonance imaging systems

Abstract

A method for transferring image impressions between different magnetic resonance imaging (MRI) systems is described. In this method, reference image data of a phantom is generated using a first MRI system for multiple different pulse sequence protocols with different parameter settings. New image data of the phantom is also generated using a second MRI system, different from the first MRI system, for multiple different pulse sequence protocols with different parameter settings. Based on the result of a cost function, adapted parameter values ​​for the different parameter settings of the second MRI system are obtained, the cost function quantifying the similarity between the image impression of the new image data and the image impression of the reference image data. Finally, the parameter settings in the second MRI system are adjusted using the adapted parameter values. A transmission device is also described. Furthermore, an MRI system is described.

Description

Technical Field

[0001] This invention relates to a method for transferring image impressions between different magnetic resonance imaging (MRI) systems. The invention also relates to a transmission device. Furthermore, the invention relates to a magnetic resonance imaging (MRI) system. Background Technology

[0002] In diagnostic imaging, achieving consistent image quality across different scanner models and software remains a challenge. This can be attributed to the different detection and / or reconstruction techniques available, and especially to different acceleration techniques, hardware configurations, hardware variations, and hardware tolerances.

[0003] These differences cause problems in the workflow because both MTRA (Medical Technical Assistant) and radiologists are trained in specific image impressions. In particular, technicians may fail to perform their quality assurance as planned, and radiologists may struggle to comment on, annotate, and evaluate image impressions when they change. The latter is especially important in situations requiring longitudinal observation of patients to determine the progression of specific diseases such as multiple sclerosis or for tumor follow-up (to track previous cancer patients or to control the progression of treatment, particularly chemotherapy and / or radiotherapy).

[0004] This makes it very difficult to introduce new technologies in this field, as clients or users want to avoid the aforementioned problems and save on the costs of reconciling new, available technologies with their accustomed image impressions. This wait-and-see attitude among clients results in a lower market penetration rate for new technologies compared to what is feasible. Consequently, patients are often scanned without optimal procedures, and the efficiency of new systems does not realize their full potential for clients or users.

[0005] To date, attempts to solve the above problems have involved very cumbersome processes in which application experts familiar with both new and old technologies try to achieve the same image impression with the new technology as they would with the old technology, while simultaneously optimizing scan time and / or resolution.

[0006] This process is based on a mix of trial and error and educated guesswork, and requires the application of extensive expert experience. This raises a number of problems, some of which are listed below.

[0007] A deep understanding is needed to find a similar starting point for creating computer programs for imaging. However, it is becoming increasingly difficult to find qualified personnel capable of undertaking this task. Furthermore, as the technology mix evolves over time, the scope of knowledge required for this task expands year by year.

[0008] Because there are no objective limitations on the image impression and it involves a trial-and-error approach, many experiments and evaluations are required through the client to achieve the desired results. Furthermore, this is largely impossible to achieve through pure phantom testing; it also requires the patient, and application experts typically need to conduct multiple trials and visits to the client.

[0009] Because the method described depends solely on the personnel performing it, it is only very limited to maintaining and ensuring that the quality remains constant, thus achieving the optimal settings.

[0010] If it is feasible to provide an automatic or semi-automatic process that gives the program at least one starting point, then this would greatly improve the current approach. Summary of the Invention

[0011] Therefore, the objective is to develop methods and apparatus for transferring image impressions between different magnetic resonance imaging systems or magnetic resonance imaging systems in different states, said methods and apparatus having improved reliability and independence from expert ability.

[0012] This objective is achieved by the method for transmitting image impressions between different magnetic resonance imaging systems according to the invention, the transmission device according to the invention, and the magnetic resonance imaging system according to the invention.

[0013] In the method according to the invention for transferring image impressions between different magnetic resonance imaging (MRI) systems, reference image data of a phantom is generated by means of a first MRI system for multiple different pulse sequence protocols with different parameter settings. "Different MRI systems" should be understood not only as MRI systems with different technical characteristics, especially different hardware, but also as MRI systems having the same or identical hardware running different software, especially different versions of software. The reference image data is recorded from the phantom, which is preferably reproducibly positioned, and particularly preferably arranged at a predetermined location in a predetermined orientation within the coordinate system of the scanning unit of the MRI system. The coordinate system is preferably identifiable in the reference image data by means of markers visible through MRI.

[0014] Furthermore, new image data of the phantom can be generated using a second magnetic resonance imaging (MRI) system for multiple different pulse sequence protocols with different parameter settings. The second MRI system differs from the first MRI system in its hardware and / or software, thus allowing for the expectation that, even when receiving the same pulse sequence protocol with the same parameter settings on different MRI systems, differences in image impressions will occur between them, provided the pulse sequence protocol is received without alteration.

[0015] Therefore, to compensate for the difference in image impression, adapted parameter values ​​for different parameter settings of the pulse sequence protocol for the second magnetic resonance imaging system are subsequently generated based on the result of the cost function, which quantifies the similarity between the image impression of the new image data and the image impression of the reference image data. The cost function should be understood as a function by which both systems can be adjusted. In this case, it involves parameterizing the second magnetic resonance imaging system so that the output image appears as similar as possible to the image of the first magnetic resonance imaging system in terms of its image impression. The cost function returns a "mistake" or "deviation" between the image impressions of the two systems and can be optimized using known methods such as regression or gradient descent. Here, the cost function includes as many sets of image data as possible, and all sets of preferred image data (reference image data and new image data), which are generated using different pulse sequence protocols.

[0016] Finally, the parameter settings of different pulse sequence protocols in the second magnetic resonance imaging system are adjusted using the adapted parameter values ​​so that the image image on the second magnetic resonance imaging system matches the image image on the first magnetic resonance imaging system.

[0017] Advantageously, the adaptation of pulse sequence protocol parameter settings can be automated. The use of a cost function replaces the adaptation performed by experts or users on new and old MRI systems. If other image characteristics or focus optimizations, particularly resolution or speed, need to be set in addition to image impression, these desired features can also be incorporated into the cost function. This alleviates the particularly complex task domain for users and greatly simplifies migration between different systems.

[0018] The transmission device according to the invention includes a reference data receiving unit. The reference data receiving unit is configured to receive reference image data from a first magnetic resonance imaging system for multiple different pulse sequence protocols with different parameter settings from a phantom.

[0019] The transmission device according to the invention also includes an image data generation unit for generating new image data of the phantom using a second magnetic resonance imaging system for multiple different pulse sequence protocols with different parameter settings. To generate new image data, pulse sequences are transmitted to the scanning unit of the second magnetic resonance imaging system based on different pulse sequence protocols. A phantom already used to generate reference image data is provided in the second magnetic resonance imaging system. Now, the original data of the phantom is detected using the pulse sequence, and new image data is reconstructed based on the detected original data. For this purpose, a reconstruction unit already present in the control device of the second magnetic resonance imaging system can also be used.

[0020] Furthermore, the transmission device according to the invention includes a calculation unit for determining adapted parameter values ​​for different parameter settings of the pulse sequence protocol for the second magnetic resonance imaging system based on the result of a cost function, wherein the cost function quantifies the similarity between the image impression of the new image data and the image impression of the reference image data. This cost function is preferably designed such that if the image impressions of the compared image data are the same, the result of the cost function approaches zero, while if the image impressions of the compared image data are significantly different, the result of the cost function takes a value significantly different from zero.

[0021] A portion of the transmission device according to the invention is also an adaptation unit, which is used to adjust parameter settings in a second magnetic resonance imaging system using adapted parameter values. For this purpose, the adapted parameter values ​​are stored in a data storage unit of the second magnetic resonance imaging system. The transmission device according to the invention shares the advantages of the method according to the invention for transmitting image impressions between different magnetic resonance imaging systems.

[0022] The magnetic resonance imaging system according to the present invention includes a transmission device, a scanning unit, and a control device according to the present invention, wherein the control device is used to manipulate the scanning unit based on parameter values ​​adapted by the transmission device according to a pulse sequence protocol.

[0023] Most of the previously mentioned components of the transmission device according to the invention can be implemented, wholly or partially, as software modules in the processor of a corresponding computing system, for example, as a control device for a magnetic resonance imaging system or a computer for controlling such a system. The largely software-based implementation has the advantage that existing computing systems can be easily upgraded via software to operate according to the invention.

[0024] In this regard, the objective is also achieved by a corresponding computer program product having a computer program that can be directly loaded into a computing unit. This computer program has program segments to execute the steps of the method according to the invention for transferring image impressions between different magnetic resonance imaging systems when the program is executed in the computing unit. In addition to the computer program, such a computer program product may optionally include additional components such as documentation, and / or additional parts, as well as hardware components, such as hardware keys (software dongles, etc.) for using the software.

[0025] For transport to and / or storage at or within a computing system, a computer-readable medium, such as a memory stick, hard disk, or other transportable or fixed-mount data carrier, can be used, on which program segments of a computer program that can be read and executed by the computing system are stored. For this purpose, the computing system may, for example, have one or more microprocessors working together.

[0026] The following descriptions contain particularly advantageous designs and improvements of the present invention. Furthermore, within the scope of the present invention, different features of different embodiments can be combined to form new embodiments.

[0027] In a preferred variant of the method according to the invention, the first magnetic resonance imaging system and the second magnetic resonance imaging system differ in at least one of the following features:

[0028] -The hardware of the corresponding system,

[0029] - The software used for imaging in the corresponding system.

[0030] Advantageously, not only hardware migration but also software migration can be compensated by the method according to the invention, so that the user can retain the usual image impression under any circumstances when making any changes to the magnetic resonance imaging system.

[0031] Preferably, different parameter settings are associated with different imaging programs and / or different pulse sequence protocols. This can be understood as imaging using different target locations and / or different pulse sequences. Advantageously, the magnetic resonance imaging system can be used for very different applications and can be migrated between different magnetic resonance imaging systems and / or different software variants or versions, making it feasible for the different applications to have the same image impression or at least at least a similar image impression on the new system.

[0032] Particularly preferably, the parameters are adjusted such that the result of the cost function is iteratively optimized in such a way that the result represents the optimal similarity between the reference image data and the new image data. Advantageously, this achieves optimal similarity between image impressions from different imaging systems.

[0033] In a preferred embodiment of the method according to the invention, in addition to the similarity of image impressions set according to the parameters of the pulse sequence, the cost function also includes additional criteria, by means of which additional targets are tracked in addition to the similarity of image impressions and / or additional conditions are considered in addition to the similarity of image impressions.

[0034] Preferably, the additional objectives include one of the following:

[0035] -Collection time,

[0036] -Activate dedicated acceleration technologies as a specific way to influence acquisition time.

[0037] - Functionality used to improve image quality.

[0038] Advantageously, additional optimization objectives can be incorporated into the adaptation process and can also be tracked automatically. The reduced acquisition time can help improve image quality in the case of moving objects.

[0039] The characteristics of the similarity between the reference image data and the newly generated image data are preferably defined by at least one of the following measurement variables:

[0040] - The numerical values ​​of image data voxels and the values ​​to be derived from them, especially grayscale values.

[0041] -contrast

[0042] -Signal-to-noise ratio

[0043] - Image resolution.

[0044] The term "numerical value" here should be understood as an intensity value associated with a voxel, which is generated based on the original data during image data reconstruction. Contrast, signal-to-noise ratio, and image resolution are influenced by the grayscale values ​​of the voxels. That is, the similarity of image data can be compared based on the grayscale values ​​of the voxels, which are fully known after the image data was recorded.

[0045] Preferably, the different parameter settings of the pulse sequence protocol include parameters that affect and / or change the image impression. Advantageously, the image impression of the new image data can be matched to the image impression of the reference image data through parameter adaptation, i.e., by changing and adjusting the parameter values ​​of the pulse sequence protocol of the new magnetic resonance imaging system.

[0046] Preferably, the different parameter settings include at least one of the following parameters:

[0047] -Filter parameters,

[0048] -Repetition time,

[0049] -Echo time,

[0050] -contrast

[0051] -Acceleration factor.

[0052] The parameters mentioned above affect the image impression in different ways.

[0053] In particular, image filters, which are associated with filter parameters, affect noise suppression in image data, and thus also affect the image impression.

[0054] Repetition time is an important parameter for setting contrast. In particular, the type of weighting, such as T1 weighting, can be set via repetition time. Furthermore, repetition time is one of the most important factors for image acquisition time. Repetition time also plays a role in saturation effects, which are particularly important in cases of very short repetition times, such as those occurring in fast sequences.

[0055] Similarly, echo time or reversal time is also important for contrast formation. The acceleration factor plays a decisive role in image quality and thus in the overall impression of the image.

[0056] Preferably, the different parameter settings do not include the following parameters:

[0057] -Slice resolution,

[0058] -Vollite count

[0059] -Image geometry,

[0060] - Check the positioning of the object or phantom.

[0061] -Navigation parameters,

[0062] - Coil settings.

[0063] Slice resolution specifically relates to the number of slices to be imaged. The slice resolution should not be changed.

[0064] The number of voxels indicates the basic resolution and should not be changed so as not to alter the image structure.

[0065] Image geometry specifically includes the size of the field of view or the size of the image representation and the size of the voxels, and is related to the number of voxels. The image geometry should also remain consistent.

[0066] The phantom's position in the isocenter should also remain unchanged in order to enable comparison of voxels one by one.

[0067] Navigation settings should also remain unchanged so as not to alter the image geometry.

[0068] Coil setup involves the use and configuration of local receiving coils, and these coil settings should remain consistent for a specific type of imaging.

[0069] In a preferred variant of the method according to the invention, the reference image data comprises a representative sub-region of the entire inspection area. Particularly preferably, the reference image data comprises a unique image slice. Advantageously, the recording time for recording the reference image data can be kept short or even minimal. Furthermore, storage requirements and resources needed for processing the reference image data can be kept low or even minimal.

[0070] Also preferably, the parameters of the pulse sequence protocol on the second magnetic resonance imaging system are automatically adjusted. Advantageously, the adaptation can be performed independently of individual professionals.

[0071] Preferably, the parameters of the pulse sequence protocol are adjusted semi-automatically. Here, suggestions for adjusting the parameters of the pulse sequence protocol used in the second MRI system are automatically provided to experts. The experts can then modify or approve the pulse sequence protocol. In an additional step, the experts have their modifications automatically checked and obtain the results. Based on the results, the experts decide whether to adopt their modifications or prefer to store the initial automated suggestions in the second MRI system. Advantageously, the experts can influence the final result of parameter fitting and, at the same time, use the automatically obtained results as a basis for decision-making, which greatly reduces the workload of the experts. Attached Figure Description

[0072] The present invention will now be described in detail again with reference to the accompanying drawings and embodiments. The drawings show:

[0073] Figure 1 A flowchart is shown, illustrating a method for transferring image images between different magnetic resonance imaging systems according to an embodiment of the present invention.

[0074] Figure 2 A schematic diagram of a transmission device according to an embodiment of the present invention is shown.

[0075] Figure 3 A schematic diagram of a magnetic resonance imaging system according to an embodiment of the present invention is shown. Detailed Implementation

[0076] exist Figure 1 The diagram shows a flowchart 100, which illustrates a method for transferring image impressions between different magnetic resonance imaging systems.

[0077] In step 1.I, reference image data (RBD) of the phantom is obtained on the first magnetic resonance imaging system MR1 for multiple different protocols P with different parameter settings. The parameter settings correspond to settings that optimize the image impression for the corresponding imaging purpose of the respective protocol. The image impression can also be matched to the individual preferences of a specific user.

[0078] In step 1.II, new image data NBD of the phantom is detected on the second magnetic resonance imaging system MR2 for multiple different protocols P with different parameter settings of the second magnetic resonance imaging system MR2. Here, it is of primary significance to select the same parameter settings as when recording reference image data RBD using the first magnetic resonance imaging system MR1 to record the new image data NBD.

[0079] In step 1.III, a cost function K is generated, which quantifies the similarity between the image impression of the new image data NBD and the image impression of the reference image data RBD.

[0080] In step 1.IV, based on the result of the cost function K, an adjustment process is performed on the parameter settings of the second magnetic resonance imaging system MR2, wherein the adjusted protocol parameter PPM for the pulse sequence protocol of the second magnetic resonance imaging system MR2 is obtained.

[0081] exist Figure 2 The diagram shows a transmission device 20 according to an embodiment of the present invention.

[0082] The transmission device 20 includes a reference data receiving unit 21, which is used to receive reference image data RBD from the first magnetic resonance imaging system MR1 for multiple different protocols for pulse sequences with different parameter settings.

[0083] The transmission device 20 also has an image data receiving unit 22, which receives new reference image data NBD from the phantom for multiple different protocols for pulse sequences with different parameter settings from the second magnetic resonance imaging system MR2.

[0084] In addition, the transmission device 20 includes a calculation unit 23, which is used to generate a cost function K, which is used to quantify the similarity between the image impression of the new image data NBD and the image impression of the reference image data RBD.

[0085] Part of the transmission device 20 is also an adaptation unit 24, which is used to adjust the parameter settings in the second magnetic resonance imaging system according to the result of the cost function K, wherein the adapted parameter value PPM is obtained.

[0086] exist Figure 3 The present invention illustrates a schematic diagram of an assembly 30 consisting of a first magnetic resonance imaging system MR1 and a second magnetic resonance imaging system MR2, according to an embodiment of the present invention. The magnetic resonance imaging system MR2 includes a scanning unit 31 and a control device 32. The control device 32 includes a transmission device 20 for generating adjusted parameter values ​​PPM, the transmission device 20 having... Figure 2 The structure is shown in the diagram. The second magnetic resonance imaging system MR2 obtains reference image data RBD from the first magnetic resonance imaging system MR1, and the reference image data RBD is used to match the image image of the second magnetic resonance imaging system MR2 with the image image of the first magnetic resonance imaging system MR1.

[0087] Finally, it should be reiterated that the methods and apparatus described above are merely preferred embodiments of the present invention, and that the present invention can be modified by those skilled in the art without departing from its scope. For completeness, it should also be noted that the use of the indefinite article "a" or "an" does not exclude the possibility that the features involved may exist multiple times. Similarly, the term "unit" does not exclude that it consists of multiple parts, which may optionally be spatially distributed. Regardless of the grammatical gender of a particular term, both male and female persons are included.

Claims

1. A method for transferring image impressions between different magnetic resonance imaging systems (MR1, MR2), the method comprising the following steps: - Reference image data (RBD) of the phantom is generated using the first magnetic resonance imaging system (MR1) for multiple different pulse sequence protocols (P) with different parameter settings. - New image data (NBD) of the phantom is generated using a second magnetic resonance imaging system (MR2) different from the first magnetic resonance imaging system (MR1) for the plurality of different pulse sequence protocols (P) with different parameter settings. - Based on the result of the cost function (K), adapted parameter values ​​(PPM) are obtained for different parameter settings of the second magnetic resonance imaging system (MR2), wherein the cost function (K) quantifies the similarity between the image impression of the new image data (NBD) and the image impression of the reference image data (RBD). - Adjust the parameter settings in the second magnetic resonance imaging system using the adapted parameter values ​​(PPM).

2. The method of claim 1, wherein the first magnetic resonance imaging system (MR1) and the second magnetic resonance imaging system (MR2) differ in at least one of the following features: - hardware, - Software used for imaging.

3. The method according to claim 1 or 2, wherein different parameter settings are associated with different imaging programs and / or different pulse sequence protocols (P).

4. The method according to claim 1 or 2, wherein the parameter settings are adjusted such that the result of the cost function (K) is optimized in such a way that the result represents the optimal similarity between the reference image data (RBD) and the new image data (NBD).

5. The method according to claim 1 or 2, wherein the similarity between the image impression of the new image data (NBD) and the image impression of the reference image data (RBD) is characterized by at least one of the following measurement variables: - The grayscale values ​​of voxels in the image data. - Contrast, - Signal-to-noise ratio, - Image resolution.

6. The method of claim 1 or 2, wherein different parameter settings include parameters that influence and / or change the image impression.

7. The method according to claim 1 or 2, wherein the different parameter settings that affect and / or change the image impression include one of the following parameters: - Filter parameters, - Repeat time, - Echo time, - Contrast, - Acceleration factor.

8. The method of claim 7, wherein the different parameter settings do not include the following parameters: - Slice resolution, - Number of pixels, - Image geometry, - Positioning of the phantom. - Navigation parameters, - Coil settings.

9. The method of claim 1 or 2, wherein the parameters of the protocol in the second magnetic resonance imaging system (MR2) are automatically adjusted.

10. A transmission device (20), the transmission device (20) comprising: - Reference data receiving unit (21), which is used to receive reference image data (RBD) of the phantom from the first magnetic resonance imaging system (MR1) for multiple different pulse sequence protocols (P) with different parameter settings. - Image data receiving unit (22), which is used to receive new image data (NBD) of the phantom from the second magnetic resonance imaging system (MR2) for the plurality of different pulse sequence protocols (P) with different parameter settings. - A calculation unit (23) is used to calculate adapted parameter values ​​(PPM) for different parameter settings of the second magnetic resonance imaging system (MR2) based on the result of a cost function (K), wherein the cost function (K) quantifies the similarity between the image impression of the new image data (NBD) and the image impression of the reference image data (RBD). - Adaptor unit (24), which is used to adjust the parameter settings in the second magnetic resonance imaging system (MR2) by means of the adapted parameter value (PPM).

11. A magnetic resonance imaging system (MR2), said magnetic resonance imaging system (MR2) having: - The transmission device (20) according to claim 10. - Scanning unit (31). - Control device (32), the control device (32) is used to control the scanning unit (31) based on the pulse sequence protocol (P) and the parameter values ​​(PPM) adapted by the transmission unit (20).

12. A computer program product comprising instructions that, when executed by a computer, cause the computer to perform the steps of the method according to any one of claims 1 to 9.

13. A computer-readable storage medium comprising instructions that, when executed by a computer, cause the computer to perform the steps of the method according to any one of claims 1 to 9.

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