Method for determining a magnetocardiogram signal from a living being

Abstract

The invention relates to a method for determining a magnetocardiogram signal from a living being, comprising the following steps: sensing a magnetic reference field strength by a sensor unit for measuring magnetic fields, sensing a magnetic measurement field strength by the sensor unit when a living being is present in the surroundings of the sensor unit, determining a magnetocardiogram signal from the living being on the basis of the magnetic reference field strength and the magnetic measurement field strength. The invention also relates to a device for determining a magnetocardiogram signal from a living being, a computer program and a machine-readable storage medium.

Description

[0001] Description

[0002] title

[0003] Method for determining a magnetocardiogram signal of a living being

[0004] The invention relates to a method for determining a magnetocardiogram signal of a living being, a device for determining a magnetocardiogram signal of a living being, a computer program and a machine-readable storage medium.

[0005] State of the art

[0006] A magnetocardiogram is the recording and visualization of the heart's magnetic field, which is generated by the electrophysiological activity of the heart muscle cells. The recording is usually performed using highly sensitive magnetic field sensors.

[0007] Quantum-based magnetic sensors are known, for example, from the published patent applications DE 10 2018 220 234 A1 and DE 10 2018 214 617 A1.

[0008] Disclosure of the invention

[0009] The object underlying the invention is to provide a concept for efficiently determining a magnetocardiogram signal of a living being.

[0010] This object is achieved by means of the respective subject matter of the independent claims. Advantageous embodiments of the invention are the subject matter of respective dependent subclaims. According to a first aspect, a method for determining a magnetocardiogram signal of a living being is provided, comprising the following

[0011] Steps:

[0012] Detecting a magnetic reference field strength by a sensor unit for measuring magnetic fields,

[0013] Detecting a magnetic field strength by the sensor unit when a living being is present in the vicinity of the sensor unit,

[0014] Determining a magnetocardiogram signal of the living being based on the magnetic reference field strength and the magnetic measurement field strength.

[0015] According to a second aspect, a device for determining a magnetocardiogram signal of a living being is provided, comprising: a sensor unit for measuring magnetic fields, wherein the sensor unit is configured to detect a magnetic reference field strength and to detect a magnetic measuring field strength in the presence of a living being in the environment of the sensor unit, and a determination device which is configured to determine a magnetocardiogram signal of the living being based on the magnetic reference field strength and the magnetic measuring field strength.

[0016] According to a third aspect, a computer program is provided which comprises instructions which, when the computer program is executed by a computer, for example by the device according to the second aspect, cause the computer to carry out a method according to the first aspect.

[0017] According to a fourth aspect, a machine-readable storage medium is provided on which the computer program according to the third aspect is stored.

[0018] The invention is based on and incorporates the finding that the above-mentioned object is achieved by detecting a magnetic field strength by the sensor unit, wherein it is determined that this magnetic field strength is a reference field strength, i.e., a reference. Subsequently, the magnetic measurement field strength is detected by the sensor unit in the presence of a living being in the vicinity of the sensor unit. The magnetocardiogram signal of the living being is determined based on this detected magnetic measurement field strength and on the previously determined or defined reference.

[0019] As a rule, the magnetic field strength detected by the sensor unit when a living being is present in the vicinity of the sensor unit originates not only from the heart's magnetic field, but also from other magnetic fields, such as the Earth's magnetic field or electrical devices such as household appliances. Such magnetic fields create interference magnetic fields for the measurement of a cardiac magnetic field. By establishing a reference before the actual magnetocardiogram measurement, which is then taken into account in the subsequent magnetocardiogram measurement, the magnetocardiogram signal can be determined efficiently. In particular, interference magnetic fields can be efficiently taken into account in this way.

[0020] This makes it advantageous to perform a long-term magnetic resonance imaging (MRI). Long-term imaging can mean several hours, such as an overnight period.

[0021] This results in the technical advantage that a concept for efficiently determining a magnetocardiogram signal of a living being is provided.

[0022] The living being is, for example, a human being or is, for example, an animal.

[0023] In the following, the abbreviation “MKG” can be used for the term “magnetocardiogram”.

[0024] In one embodiment of the method, a background signal is determined based on the magnetic reference field strength, which represents a magnetic background of the environment surrounding the sensor unit, and the magnetocardiogram signal is determined based on the background signal. This provides, for example, the technical advantage that the magnetocardiogram signal can be determined efficiently. According to this embodiment, the magnetic background of the environment surrounding the sensor unit is determined based on the magnetic reference field strength and is taken into account when determining the magnetocardiogram signal.

[0025] The magnetic background can, for example, result from or be based on the Earth's magnetic field.

[0026] In one embodiment of the method, it is provided that, based on the magnetic reference field strength, an interference signal is determined which represents a magnetic interference in the environment of the sensor unit, wherein the magnetocardiogram signal is determined based on the interference signal.

[0027] This provides, for example, the technical advantage that the magnetocardiogram signal is determined efficiently. According to this embodiment, it is therefore provided that, based on the magnetic reference field strength, a magnetic disturbance in the vicinity of the sensor unit is determined, which is then taken into account when determining the magnetocardiogram signal. Magnetic disturbance can, for example, result from the operation of an electrical device in the vicinity of the sensor unit. Such an electrical device is, for example, an electrical household appliance or a drive motor for an electric roller shutter.

[0028] For example, if the sensor unit is located in a vehicle, such as a motor vehicle or an aircraft, such magnetic interference may result from the operation of the vehicle.

[0029] For example, such magnetic interference can result from an electrically powered rail vehicle traveling in the vicinity of the sensor unit. The power consumption of such a rail vehicle can generate magnetic fields that can interfere with the MCG measurement.

[0030] In one embodiment of the method, it is provided that the signal to be determined based on the magnetic reference field strength, i.e. the background signal and / or the interference signal, is determined using a pattern recognition method, in particular a machine learning method.

[0031] This provides the technical advantage, for example, that the background signal or the interference signal can be determined efficiently.

[0032] In one embodiment of the method, it is provided that the signal to be determined based on the magnetic reference field strength, i.e. the background signal and / or the interference signal, is filtered out from a measurement signal representing the detected magnetic measurement field strength in order to obtain a filtered measurement signal, wherein the magnetocardiogram signal is determined based on the filtered measurement signal.

[0033] This provides, for example, the technical advantage of efficiently determining the magnetocardiogram signal. According to this embodiment, the magnetic background and / or magnetic interference are filtered out of the detected magnetic measurement field strength.

[0034] In one embodiment of the method, it is provided that at least one time interval is determined, in particular estimated, within which the magnetic disturbance occurs and / or will occur, wherein only a magnetic measurement field strength detected outside the at least one time interval is used to determine the magnetocardiogram signal.

[0035] This provides, for example, the technical advantage that the magnetocardiogram signal can be determined efficiently. According to this embodiment, it is therefore provided that detected magnetic disturbances are not taken into account when determining the magnetocardiogram signal. Thus, on the one hand, measurements can only be taken outside the time interval, i.e., the magnetocardiogram measurement can be performed. On the other hand, an oral and maxillofacial measurement performed within the time interval can additionally or alternatively be disregarded when determining the magnetocardiogram signal. In one embodiment of the method, it is provided that at least one vital parameter of the living being is determined based on the magnetocardiogram signal.

[0036] This provides the technical advantage, for example, that at least one vital parameter of the living being can be determined efficiently.

[0037] In one embodiment of the method, it is provided that the at least one vital parameter is an element selected from the following group of vital parameters: heart rate, heart rate variability, duration and / or amplitude of an ECG-equivalent signal change, for example P-wave, QRS complex, T-wave and corresponding combinations.

[0038] This provides the technical advantage, for example, that particularly suitable vital parameters can be determined efficiently.

[0039] In one embodiment of the method, it is provided that the measuring area comprises a section of an object which is an element selected from the following group of objects: mattress, pillow, bed, chair, sofa, armchair, headrest, seat, vehicle seat, aircraft seat, airplane seat, motor vehicle seat.

[0040] This provides the technical advantage, for example, that particularly suitable measuring ranges can be provided.

[0041] In one embodiment of the device, it is provided that the measuring area comprises a portion of an object which is an element selected from the following group of objects: mattress, pillow, bed, chair, sofa, armchair, headrest, seat, vehicle seat, aircraft seat, airplane seat, motor vehicle seat.

[0042] This results in the technical advantage, for example, of being able to use particularly suitable measuring ranges. The technical functionalities of the device result analogously from the corresponding technical functionalities of the process, and vice versa. This means that device features, in particular, result from process features, and vice versa.

[0043] For example, it is specified that the device is configured to carry out all steps of the method according to the first aspect.

[0044] For example, it is provided that the method according to the first aspect is carried out or performed by means of the device according to the second aspect.

[0045] According to one embodiment, the method is a computer-implemented method.

[0046] The phrase “at least one” means “one or more”.

[0047] The embodiments described here can be combined with each other in any way, even if this is not explicitly described.

[0048] The detection of the magnetic reference field strength by the sensor unit is carried out, for example, in the absence and / or presence of a living being in the vicinity of the sensor unit.

[0049] The magnetic field strength detected when a living being is present in the vicinity of the sensor unit can, for example, be used as a magnetic reference field strength for a later MKG measurement. This means that an MKG measurement can also be used as a reference for later MKG measurements. This advantageously allows magnetic disturbances that do not occur regularly over time, or that did not occur, for example, during the recording of the magnetic reference field strength, to be detected and taken into account for an MKG measurement.

[0050] An MCG measurement involves detecting the magnetic field strength with the sensor unit in the presence of a living being in the vicinity of the sensor unit and determining the magnetocardiogram signal. The output or result of the MCG measurement is the magnetocardiogram signal.

[0051] For example, multiple magnetocardiogram signals can be detected. Statements made in connection with one magnetocardiogram signal apply analogously to multiple magnetocardiogram signals, and vice versa.

[0052] In one embodiment of the method, a distribution of interference signals over time and / or a spectral distribution of the interference signals are determined, wherein the magnetocardiogram signal is determined based on the respective distribution.

[0053] This results in the technical advantage, for example, that the magnetocardiogram signal can be determined efficiently.

[0054] The invention is explained in more detail below using preferred embodiments. These show:

[0055] Fig.1 is a flowchart of a method for determining a magnetocardiogram signal of a living being,

[0056] Fig. 2 shows a device for determining a magnetocardiogram signal of a living being,

[0057] Fig. 3 a machine-readable storage medium and

[0058] Fig. 4 several interference signals measured over several nights in a row.

[0059] Fig. 1 shows a flowchart of a method for determining a magnetocardiogram signal of a living being, comprising the following steps: detecting 101 a magnetic reference field strength by a sensor unit for measuring magnetic fields,

[0060] Detecting 103 a magnetic measuring field strength by the sensor unit in the presence of a living being in the vicinity of the sensor unit, determining 105 a magnetocardiogram signal of the living being based on the magnetic reference field strength and the magnetic measuring field strength.

[0061] Fig. 2 shows a device 201 for determining a magnetocardiogram signal of a living being, comprising: a sensor unit 203 for measuring magnetic fields, wherein the sensor unit 203 is configured to detect a magnetic reference field strength and to detect a magnetic measuring field strength in the presence of a living being in the environment of the sensor unit 203, and a determination device 205 which is configured to determine a magnetocardiogram signal of the living being based on the magnetic reference field strength and the magnetic measuring field strength.

[0062] Fig. 3 shows a machine-readable storage medium 301 on which a computer program 303 is stored. The computer program 303 includes instructions that, when executed by a computer, cause the computer to perform a method for determining a magnetocardiogram signal of a living being.

[0063] Fig. 4 shows a first time axis 401, a second time axis 403, a third time axis 405 and a fourth time axis 407. The four time axes indicate four immediately consecutive nights, which can also be referred to below as Night 1, Night 2, Night 3 and Night 4.

[0064] A device for detecting a magnetocardiogram signal is provided. For example, the sensor unit is integrated into a mattress of a bed. The detection device can be provided outside the mattress, for example, or can also be located inside the mattress.

[0065] To determine a reference field strength, the sensor unit is designed to measure magnetic fields, i.e., to detect a magnetic field strength, during Night 1 without any living being in the vicinity of the sensor unit. This means that magnetic fields can be recorded or detected using the device during Night 1. Such magnetic fields represent magnetic interference fields for subsequent MKG measurements during Nights 2 to 4.

[0066] For example, three magnetic interference fields were measured in Night 1: a first interference signal 409, a second interference signal 411, and a third interference signal 413. The second interference signal 411 occurred twice during Night 1, as shown by the first time axis 401.

[0067] In addition, an oval with the reference number 415 was drawn around the interference signals 409, 411, 413 to indicate that these interference fields or interference signals have not yet been filtered out from an MKG measurement signal.

[0068] However, on the following nights, Night 2 to Night 4, these interference signals can be filtered out from the field strengths measured at that time. This is symbolically indicated by an X with the reference number 417. This means that on the following nights, Night 2 to Night 4, a living being, for example a human, is lying on the mattress. Furthermore, it is intended that during the nights Night 2 to Night 4, the sensor unit detects or measures magnetic field strengths, the magnetic field strengths. Measurement signals corresponding to this measurement can then serve as the basis for a magnetocardiogram signal of the living being. In this case, it is intended that the interference signals determined on Night 1, the reference night, are filtered out from the measurement signals recorded on the following nights, Night 2 to Night 4.

[0069] As an example, it is shown that a fourth magnetic interference field 419 was detected on night 2, which can also be filtered out on the following nights, night 3 and night 4.

[0070] Such interference fields can be detected, for example, using a machine learning algorithm or artificial intelligence. For example, a pattern recognition method can be used to identify patterns in the magnetic reference field strengths, which can then be filtered out from the measurement signal available on subsequent nights, for example, Night 2 to Night 4.

[0071] In summary, the concept described here is based, for example, on a reference measurement and pattern recognition based on the reference measurement, so that recognized patterns can be taken into account when determining magnetocardiogram signals from a living being. For example, it is envisaged that a background signal and / or an interference signal is / are also determined based on the magnetic measurement field strength, which can then be used for further maxillofacial measurements to filter out corresponding magnetic background and / or corresponding magnetic interference from the measurement signal. This means that the determination of a magnetic background and / or the determination of magnetic interference can also be carried out for the magnetic measurement field strength in the same way as for the magnetic reference field strength. The corresponding explanations apply analogously.Thus, the magnetic field strength can also be evaluated using a pattern recognition method, in particular a machine learning method, to determine the background signal and / or the interference signal. These detected signals can then be used for subsequent maxillofacial measurements to determine the corresponding magnetocardiogram signal of the living being based on these signals.

[0072] For example, efficient noise suppression can be advantageously achieved. This also advantageously provides feedback on whether the device is functioning fully or only partially, and, for example, how long this condition is expected to persist. In particular, the distribution of interference signals over time and / or the spectral distribution of the interference signals are taken into account.

[0073] In order to identify a background signal or an interference signal, it is intended, for example, to measure it. For this purpose, an initial reference measurement is carried out, for example a measurement of magnetic reference field strengths, for example over the course of one night without any living being in the vicinity of the sensor unit. The vicinity of the sensor unit can generally also be referred to as a measuring area. After that, on subsequent nights, a magnetocardiogram measurement can be carried out on a living being that is in the measuring area. This means that a magnetic measuring field strength is recorded by the sensor unit when the living being is in the vicinity of the sensor unit.

[0074] The fact that the reference measurement can be carried out overnight is to be understood as an example. Shorter periods of time, for example a few minutes, can also be provided. For example, a few minutes are sufficient during a self-calibration of the sensor unit and / or the device. This means, for example, that an embodiment of the method is carried out during a self-calibration of the sensor unit and / or the device. This means, in particular, that method steps are carried out, for example, during a self-calibration of the sensor unit and / or the device. A few minutes are also sufficient, for example, if the method is or is to be used in a vehicle, for example a motor vehicle, or in a hospital.

[0075] For example, it is generally provided that the magnetic reference field strength is subtracted from the measured magnetic measurement field strength. This is done in particular in a time-of-day synchronized manner, and generally in a time-synchronized manner. For example, the reference signal is subtracted from the measurement signal, with the magnetocardiogram signal being determined, for example, based on the correspondingly subtracted measurement signal. For example, it is provided that at times or time intervals at which interference signals and / or background signals occur according to the magnetic reference field strength, corresponding filters are provided to filter these interference signals and / or background signals out of the measurement signals. In this way, for example, interference signals that always occur at the same times can be efficiently filtered out. For example, magnetic interference triggered by a drive motor of an electric roller shutter can be efficiently filtered out in this way.For example, based on the magnetic reference field strength, it can be determined that the roller shutter will be raised or lowered at a certain time, so that an interference signal can be expected at these times. This means that this interference signal can be filtered out in the measurement signal at these times. For example, patterns in the magnetic reference field strengths can be recognized. Such patterns can also be learned at the time of occurrence of the interference signal. This means that if it is known that an interference always occurs at the same time, then the temporal progression of the magnetic reference field strength at these times is defined as the pattern to be filtered out. One example is if an electrically powered rail vehicle travels in the vicinity of the sensor unit at approximately the same or similar times and thus interferes with the M KG measurement due to the current consumption of the drive motor.In this way, the filters for data analysis can be adapted in a particularly efficient manner for specific times of day or night.

[0076] Classic pattern recognition methods and / or machine learning can be used here. For example, characteristic noise patterns can be identified in the reference data, i.e., in the recorded magnetic reference field strength, such as the passing of a rail vehicle, such as a tram, or the movement of an elevator. The detected noise patterns can then be subtracted from the measured signal, i.e., the measurement signal, for noise suppression, or the corresponding filter criteria can be learned.

[0077] Through continuous analysis of the measurement data, i.e. the magnetic field strength, further patterns can be identified and data quality can be advantageously improved.

[0078] By identifying points in time or patterns with particularly high levels of noise, it is possible, for example, to identify time periods with reduced functionality with regard to an oral and maxillofacial measurement. This allows these time periods to be disregarded for further analyses or to provide feedback on the non-functionality of the device with regard to the oral and maxillofacial measurement. A particular advantage is that the identification of patterns can be used to predict the likely duration and severity of the disruption. Data weighted according to the patterns described in this way can then be managed in a database, for example, online, and can be used in data analysis and associated functionality, such as an alarm that a functionality is restricted.

Claims

Claims 1. A method for determining a magnetocardiogram signal of a living being, comprising the following steps: detecting (101) a magnetic reference field strength by a sensor unit for measuring magnetic fields, detecting (103) a magnetic measuring field strength by the sensor unit in the presence of a living being in the vicinity of the sensor unit, Determining (105) a magnetocardiogram signal of the living being based on the magnetic reference field strength and the magnetic measuring field strength.

2. The method according to claim 1, wherein based on the magnetic reference field strength a background signal is determined which represents a magnetic background of the environment of the sensor unit, wherein the magnetocardiogram signal is determined based on the background signal.

3. The method according to claim 1 or 2, wherein based on the magnetic reference field strength an interference signal (409, 411, 413, 419) is determined which represents a magnetic interference in the environment of the sensor unit, wherein the magnetocardiogram signal is determined based on the interference signal (409, 411, 413, 419).

4. The method according to claim 2 or 3, wherein the signal to be determined based on the magnetic reference field strength, i.e. the background signal and / or the interference signal (409, 411, 413, 419), is determined using a pattern recognition method, in particular a machine learning method.

5. Method according to one of claims 2 to 4, wherein the signal to be determined based on the magnetic reference field strength, i.e. the background signal and / or the interference signal (409, 411, 413, 419), is filtered out from a measurement signal representing the detected magnetic measurement field strength in order to to obtain a filtered measurement signal, whereby the magnetocardiogram signal is determined based on the filtered measurement signal.

6. Method according to one of the preceding claims as far as dependent on claim 3, wherein at least one time interval is determined, in particular estimated, within which the magnetic disturbance occurs and / or will occur, wherein only a magnetic measuring field strength detected outside the at least one time interval is used to determine the magnetocardiogram signal.

7. Method according to one of the preceding claims, wherein at least one vital parameter of the living being is determined based on the magnetocardiogram signal.

8. The method according to claim 7, wherein the at least one vital parameter is an element selected from the following group of vital parameters: heart rate, heart rate variability, duration and / or amplitude of an ECG-equivalent signal change, for example P-wave, QRS complex, T-wave and corresponding combinations.

9. A device (201) for determining a magnetocardiogram signal of a living being, comprising: a sensor unit (203) for measuring magnetic fields, wherein the sensor unit (203) is configured to detect a magnetic reference field strength and a magnetic measurement field strength in the presence of a living being in the environment of the sensor unit (203), and a determination device (205) which is configured to determine a magnetocardiogram signal of the living being based on the magnetic reference field strength and the magnetic measurement field strength.

10. The device (201) according to claim 9, wherein the measuring area comprises a portion of an object which is an element selected from the following group of objects: mattress, pillow, bed, chair, sofa, armchair, headrest, seat, vehicle seat, aircraft seat, airplane seat, motor vehicle seat.

11. A computer program (303) comprising instructions which, when executed by a computer, cause the computer program (303) to execute a method according to one of claims 1 to 8.

12. A machine-readable storage medium (301) on which the computer program (303) according to claim 11.

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