UA21299U - Method for recording magnetocardiogram - Google Patents

Abstract

The method for recording magnetocardiogram of human heart is based on the non-invasive magnetocardiography (MCG) technique. The electronic balance is used. When the signals falls outside the limits of the dynamic range of MCG, the nulling is performed for restoring the signal within these limits. When this measure is not effective, the termocycling (warming) of the magnetic field sensor (s) above the critical temperature of the superconductor is performed. In the case of the pulse obstacles, the measurements at these points are repeated. Upon recording, MCGs are processed. When the quality of the signal at certain spatial point (s) is insufficient or the signals in the upper row of the measuring grid are weak, MCGs are recorded once again.

Description

Description of the invention

The useful model belongs to medicine, namely to cardiology and can be used in the instrumental 2 diagnosis of cardiac diseases using the magnetocardiography (MKG) method, to monitor the population in order to determine the risk of cardiac diseases, as well as to study electrophysiological processes in the human heart for scientific purposes .

The relevance of developing a new method is based on the fact that today reliable diagnosis of cardiac diseases, especially in the early stages, still remains a clinical problem. The reasons 70 are that the existing methods have a low diagnostic value in certain pathologies (for example, the electrocardiogram (ECG) at rest is often normal). Load tests (cycling ergometry) and invasive methods (transesophageal electrocardiostimulation) may be accompanied by a certain risk to the health of patients, and therefore cannot be used in a number of pathologies. A number of modern methods, such as echocardiography (EchoCG) and MR-tomography reflect mainly the mechanical functions and morphological structure of the heart, but do not provide data on the electrophysiology of the myocardium. The methods of X-ray coronary angiography (coronary angiography) and radioisotope methods are both expensive, invasive and cause a negative impact on the human body (X-rays and radioactive particles), and therefore have limited application only in certain clinical situations (for example, before surgery) and cannot be repeatedly to be repeated, for example - for the purpose of monitoring the effectiveness of treatment.

In contrast, magnetocardiography (MKG) is a completely non-invasive and safe method that does not cause a negative impact on the human body and can be repeated many times both during treatment and during outpatient examinations. As shown in a number of studies, ICG has additional information compared to ECG.

Neag Oizease / 9. ap (p. ZigoiipkK, V. Moogde ei aiYi. // 9. Eiesigosagaiodu. - 1990. - M.23. - p.315-322).

That is why clinics have devices for recording ICG - magnetocardiographs. However, the introduction of this method into clinical practice is hampered by the lack of sufficiently developed medical support, primarily - examination methods, methods for analyzing ICG information, methods for finding diagnostic criteria for various pathologies, and ultimately - methods for diagnosing certain cardiac pathologies and using ICG for various clinical situations. at

In order to use the ICG method, a method of recording magnetocardiograms is necessary, which would include a clear and Ge"! an algorithm of actions that is understandable to both doctors and average medical personnel, as a result of which the registration will be successfully performed, and the received signal will have a quality that is portable for diagnosis. The modern level of the technique of SC is characterized by the fact that there is no description of such a technique in the medical literature | see for example - Vynohradova "--

T.S., Akulova F.D., Belotserkovsky 3.B. etc., Instrumental methods! research on the cardiovascular system of 32 systems - M.: Medicine, 1986. - 416 p.). The reason is that this method is new, and therefore there is no standard registration method for it.

Issues of the construction of technical means, as well as methods of examination, processing and diagnostics based on the study of magnetic signals are reflected in inventions belonging to class AbЕ1В5/04. A patent search on a more detailed European classifier, giving the class AbЕ1В5/04М, indicates 106 patents. However, most of them (70) are devoted to devices, and only 38 consider application issues. c However, most of the inventions are devoted to methods of data processing and methods of diagnosing pathologies

From the heart. In addition, most patents describe methods for measuring biomagnetic fields regardless of the source of the field, and therefore do not take into account the specifics of recording magnetocardiograms. Among the patents, 6 were found that relate to the registration of cardiomagnetic fields and protect the method itself (or including it): 1. MO 0217769, Izspetia idepiyisayeop, doapiyisavonp apa ragia! Iosaiigavnop ip MOSS, A. VaKpagem, OBA, 2002. o 2. MO 0205713, Sagaas tadpeiiis iey aiadpoleg iog aiygia! PiCheg apa aiygia! TrgiPyatsyop apa teiioy og - idepituipu eiesigis (gpipu raiy oi aigia! YaiKeg, 2002.

Z. MO 0106907, MeiShody apa demise og teavygipd Biotadpeis apa ip rapiscshiag sagayuyutadnpeiiis PTeidv, M. o zozpii2Ku, ER. 5івіпрего, Сегтапу, 2001. (Те) 20 4. ОЕ 10037519, Аррагайив апа теййой їтог теазигіпд Біотадпейіс, езресіаПу сагаіотадпейїіс, Пед изевз зуирегсопдисіїпуд дапіцт іпіепегепсе демісе Наміпуд сиггепімоМаде сигме м/йй пувієгезів апа орегайпд іп со геіахайоп-озсіПакцоп тоде, М. Зозпі (2Ku, R. (eiprego, 2001. 5. MO 0200108, Meifoy yog defeptipipd a diadpoviisayu geiemapi ragatefes pot (She eIesigo-sagaiodgarpisa! apa tadpeyosagaiodgarpisa! daya oi a rayepi, RE. 5iviprego, M. Vydpuk, M. Bozpii 2Ku, 2002 29 6. OE10128293, To aiadpose sagaias apegiai disease izipd rayepi ESO- apa MoSO daiya, and sNagasiegiviis s rpase apdiee iz deYegtiped Bbeyeep ESO apa EME mesioggv, M. bozpii2Ku, M. Viapuk, R. Z(eiprego, 2002.

In patent MUHO 0217769, a method of diagnosing coronary heart disease (CHD) is considered, in which CHD is classified into 4 degrees according to the presence of changes in the vertical coordinate (the depth of lying) of the effective dipole along the 5T segment. At the same time, the method of processing and diagnostics is considered, and the specifics of the signal registration procedure 60 are not considered. Similarly, MUMO patent 0205713 protects the method of data processing and detection of the excitation trajectory in the myocardium during atrial fibrillation. At the same time, the actual method of registration and recording of magnetocardiograms is not considered.

Patent UUO 0106907 and its national analogue OE10037519, which are taken here as a prototype, consider both the 7-channel magnetocardiograph and, in part, the examination methodology. At the same time, the following is protected: (in brackets, because the corresponding item of the formula of UUO 0106907 is indicated)

1. Measurements are carried out using a SQUID magnetometer operating in pulse-relaxation mode (1). 2. The movement of the measurement object relative to the input coil (28) is used. 3. Moving the object to one or more positions (41) is used. 4. When moving the object relative to the input coil, the input coil is stationary (42). 5. Measurements are carried out at 36 spatial points of a rectangular grid with a step of 4 cm (43). 6. The device is intended for measurements in unshielded conditions (44).

Patent MUO 0200108 and its national analogue OE 10128293 consider the method of processing and searching for 7/0 diagnostic parameters on the combination of ECG and MCG (the angle between the directions of the electrical vector of the heart and the equivalent current dipole). They use the method and the device described in the patents UHO 0106907 and

OE 10037519.

In Ukraine, the following patents and applications relating to ICG are known: 1. Method of diagnosis of myocardial infarction, SHA 53455, Stadniuk L., Kozlovskyi V., Budnyk M., Nizhenkivskyi 75 1. 2003. 2. Method of diagnosis of non-C myocardial infarction, Sha 53456, I. Voytovych, V. Kozlovskyi, L. Stadniuk, Budnyk

M., 2003. 3. Method of diagnosis of ischemic heart disease, SHA 74466, Kozlovskyi V., Budnyk M., Stadniuk L., Ryzhenko t., 2005. 4. Method of assessing the heterogeneity of the processes of electrical excitation and recovery in the heart, SHA 13427, 2006,

Zakhrabova 0., Budnyk M., Stadniuk L. and others. 5. Method of magnetocardiographic examination, application for invention Mo20040605073, Budnyk M., Minov Yu.,

Shpylovy P. 6. Method of magnetocardiographic mapping, application for invention Mo20040605074, Budnyk M., Kozlovskyi V.,

Stadnyuk L., Ryzhenko T., Zakhrabova 0. 7. Method of processing cardiographic signals, application Mots200607153, Budnyk M., Sosnytskyi V., Ryzhenko T. and others.

However, the first four patents relate to the use of ICG for the diagnosis of various cardiac diseases, but do not consider the procedures for examination, registration and processing of magnetocardiograms. The application Mo20040605073 b zo protects the sequence of actions when performing an ICG examination as one of the methods of clinical diagnosis. Application

Patent No. 200607153 protects the sequence of actions during the pre-processing of already registered magnetocardiograms, and application No. 20040605074 describes the sequence of subsequent actions of the operator for building sets of magnetic maps.

In addition, some issues of ICG registration are considered in the methodological recommendations for magnetocardiography --

Magnetocardiography (methodology and diagnostic capabilities) (V.O. Bobrov, L.A. Stadnyuk, V.I. Kozlovskyi et al. // Methodological recommendations: Ministry of Health of Ukraine, Ukrainian Center for Scientific Medical Information and Patent and Licensing Work - Kyiv - 1997. - 20 p. and in the preprint of the Institute of Cybernetics of the National Academy of Sciences, diagnostic criteria for chronic coronary heart disease based on registration and analysis of magnetocardiograms (Budnyk M., Voytovych I., Chaikovskyi !. and others. // Preprint 2002-5, National Academy of Sciences of Ukraine. In -t of Cybernetics named after V.M. Glushkov; Kyiv, 2002. - 49 p. 4. However, they are based on "the experience of working with a 1-channel magnetocardiograph, and the registration procedure itself is outlined schematically. c Thus, the analysis of the current state in this field shows , that there is no detailed description of the method of recording ICG signals in unshielded conditions of the clinic. The reason that most patents are not considered separately;" methods of ICG registration is that they are focused on the use of expensive multi-channel biomagnetic systems that require the use of installation of a magnetically shielded camera (MEK).

This useful model summarizes the experience of using a low-cost 7-channel magnetocardiograph, improved compared to the prototype, aimed at examination without MEK. In addition, our useful model provides the possibility of conducting an examination also with the help of a 1-channel magnetocardiograph. - The disadvantages of the prototype method are that:

GI - it is not indicated to use means of cleaning the signal from interference in order to facilitate the visual

Signal monitoring by the operator during registration; and, - it is not indicated whether this measurement (point) is re-registered in the presence of obstacles, and which ones;

Ge - it is not specified whether this measurement (point) is re-registered with a small amplitude of the useful signal in the 1st row of the grid; - the actions to be taken by the operator in the event of a signal going beyond the dynamic range of the magnetocardiograph are not indicated; - cases of capture (freezing) by SQUIDs of a large magnetic flux and actions of the operator in this connection are not indicated; - express signal quality control is not used immediately after its registration, - it is not specified whether the entire card is re-registered and when it happens. This useful model is based on the task of improving the method of recording magnetocardiograms, in which, through the use of new actions, modes of execution of actions, and their empirically determined logical sequence, guaranteed registration of a set of magnetocardiograms of the heart without magnetic shielding is ensured with a signal/noise ratio level sufficient for conducting medical diagnostics.

In other words, the purpose of this useful model is to develop a registration procedure in the form of a clear and comprehensible algorithm for service personnel, which makes it possible to record an ICG signal of appropriate quality in the computer memory in the presence of a high level of industrial magnetic interference.

What is new compared to the prototype method is that: 1) an electronic balance procedure is used, which is implemented by software, in order to facilitate visual monitoring by the operator of the signal when it is displayed on the display screen; 2) in order to increase the signal-to-noise ratio, it is envisaged to repeat the measurements at the points, during the registration of which inharmonic and/or other strong interferences were visually observed;

C) the use of the zeroing procedure is provided when the signal is outside the dynamic range of the device; 4) the use of thermocycling of the sensor (s) of the channel (s) by heating them above 7/0 of the critical temperature of the superconductor in case of capture of the magnetic flux is provided for; 5) in order to control the quality of the card, express processing is provided immediately after registration with the output of all 36 signals on the display screen; 6) in order to guarantee the quality of the map, its re-registration is provided, if after express processing it is found that the amplitude of the signal is insufficient at some points;

The main idea of a useful model is to improve the quality of the magnetocardiogram with the help of the improvements specified in clauses 1-6, as a result of which the reliability of the medical opinion increases, as well as to provide the operator with a clear and logical algorithm of actions, as a result of which, with the help of 7 -channel device, the registration of a high-quality ICG map will always be successfully carried out in the presence of a high level of man-made magnetic interference without MEK.

A brief description of the illustrations:

Fig. 1 - ICG view of a signal with impulse interference, the registration of which must be repeated at this point.

Fig. 2 - View of the ICG signal on the monitor screen without an electronic balance.

Fig. 3 - View of the ICG signal on the monitor screen using an electronic balance.

Fig. 4 - ICG view of a signal that has exceeded the limits of the dynamic range.

Fig. 5 - View of 36 ICG signals after express processing, subject to re-registration (there is an impulse interference at point 4-1, which corresponds to the 5th row, 2nd column). -

Figb - View of 3b-th ICG signals after express processing, which are subject to re-registration (low-frequency harmonic interference is present).

Fig. 7 - View of 36 ICG signals in a patient whose heart is displaced downwards. Gee! zo Fig. 8 - View of 36b-th ICG signals of proper quality, which are not subject to re-registration, but must be used for further processing. Me)

The proposed method is based on several consecutive actions, which make it possible to successfully register magnetocardiograms and record them in the memory of a personal computer (PC). The registration is performed by the operator - the person who controls the magnetocardiograph, the process of recording ICG signals and their recording in the PC, - c5 fills out the patient's electronic card, carries out express processing and is at the workplace in front of the PC, and c who should preferably have a technical education. The registration procedure consists of 3 stages: 1) Preparatory stage, 2) Registration of the ICG card, 3) Final stage. Let's consider them sequentially in time as they are performed. 1. The preparatory stage consists in the fact that the patient is placed on a mobile bed, placed in accordance with the receiving antennas, the bed is tied to a standard MKG grid, electrodes of the "reference ECG" are placed on it, and the bed is rigidly fixed at the starting point of the grid. This stage is the essence of another with the invention of Izayavka Mo20040605073, "Method of magnetocardiographic examination", priority from 06.29.2004). It must be performed by another person with a medical education. ;" The subject of this useful model is the algorithm of actions performed by the operator itself. During this stage, the operator opens a new examination in the electronic database, fills in the patient's electronic card and activates the data registration program. ko 2. Registration of the ICG card. Card registration consists in sequential registration of heart signals at 36 spatial points. The method of moving the bed in space depends on the number of channels of the magnetocadiograph and is also the subject of the specified application. In this implementation, the duration of registration at one point can be set from 30 minutes to 2 minutes. During signal registration at the point, the operator performs visual monitoring of signal quality. This is necessary due to the fact that inharmonic impulse interference (jumps and single IC pulses) are poorly filtered, because their frequency spectrum lies in a wide frequency band.

Ge) At the same time, strong interferences that are several times higher than the amplitude of the MCG signal can be automatically removed by setting a certain amplitude in the program, when exceeding which the interferences are removed. But weaker interferences, the amplitudes of which are approximately equal to or less than the maximum (as a rule, K) wave of the MKG signal, must be removed manually. When registering in unshielded conditions, when such impulse interference occurs (Fig. 1), the operator must repeat the registration of this point. c However, without MEK in the conditions of a city clinic, the harmonic interference of the network frequency (50 Hz and its harmonics) significantly exceeds both the useful ICG signal and all other interferences (Fig. 2). Therefore, the operator cannot recognize impulse interference and the useful signal of the heart against the background of harmonic interference. In order to implement this possibility in this useful model, it is proposed to apply the electronic balance (EB) procedure. It consists in subtracting interference signals registered by the reference vector magnetometer (RVM) from the ICG signals. In more detail about EB - Budnyk M-, Nazarenko B., Ryzhenko T.,

Maistrenko V., Multichannel magnetocardiograph, Bulletin of NTUU KPI. Instrumentation. Mo25, 2003, pp. 126-133).

At the same time, the weight coefficients of the RVM channels are calculated when registering obstacles in the absence of the patient, and therefore are constant.

As a result, the EB procedure does not take into account the change in the noise environment, so its quality is relatively poor and, as a rule, insufficient for processing ICG signals. Therefore, we propose to use EB only for visualization, i.e. cleaning of the ICG signals of the channels displayed on the PC display. As a result, the stationary industrial frequency interference on the PC display is significantly reduced and all weaker signals - the heart signal and impulse interference - become visible (Fig. 3).

However, during measurements without MEK, much stronger impulse disturbances are also possible, which go beyond the dynamic range of the magnetocardiograph (Fig. 4). In reality, the dynamic range is limited by the input range of the analog-to-digital converter (ADC), which in this implementation is 4108. In this case, the signal does not need to be registered, so the procedure for accumulating data on the hard disk is suggested to be interrupted. 70 In this implementation, this happens automatically by the data logging program and does not require operator intervention.

To return the signal to the limits of the dynamic range in this useful model, nulling is applied, which is a standard technique for devices with negative feedback, which are magnetic field sensors based on SQUIDs (superconducting quantum interference sensors) (for details, see patent OA 75434, Sensor of ultra-weak magnetic fields, Yu. Minov, M. Budnyk, P. Shpylovy, 20061.

In this implementation, such zeroing occurs automatically using the Atsiogee (auto-zero) function of the magnetocardiograph control system | see patent SHA 74679, Microprocessor control system of a multi-channel SQUID magnetometer, P. Sutkovy, A. Rusanov, M. Budnyk, 2006). However, if the signal has not returned within the specified limits within a few seconds, this useful model assumes that the operator must press the reset button himself and, after the signal returns within the range, repeat the registration of this point.

In addition, there are cases when multiple applications of zeroing do not result in a signal appearing on the display screen. This means that the SQUID captured a significant magnetic flux in this channel. This is a parasitic phenomenon that arises from the physical nature of superconductors and is related to the phenomenon of magnetic flux quantization. The reason for such a phenomenon can be extremely strong impulse interference, which can contribute several thousand to the SQUID

Magnetic flux quanta. In this case, it is necessary to perform the SQUID thermal cycling procedure. It consists in its heating above the critical temperature of the superconductor and subsequent cooling below the temperature specified in (c) (in this implementation, this is the boiling point of liquid helium at 4.2K).

For this, the operator must switch to the control mode and initiate the SQUID heating process of the corresponding channel(s). At the same time, the SQUID goes into the normal (resistive) state and the mentioned dz

The magnetic flux comes out of the SQUID. For this, the design of the sensor provides for special heaters (ША 75434), and the heating process itself occurs automatically under the control of the specified control system (ША 74679). ia

After thermal cycling of the sensor, the operator must adjust the appropriate channel (set the operating point, close the feedback loop, carry out zeroing), after which he is able to register the magnetic field and repeat the registration of this point. - 3. The final stage. The operator saves the results of the examination in the database and carries out pre-processing and averaging of 36 ICG signals in automatic mode. This is the so-called express processing, as a result of which it is possible to control the quality of registered magneto-cardiograms. If the quality of the averaged magnetocardiograms at some points of the measuring grid is insufficient. For example, in Fig. 5 - there is an impulse interference at point 4-1 (5th row, second column), or in Fig. b - there is a low-frequency harmonic " interference at all points, then the operator must return to the measurement mode and re-register 8 with magnetocardiograms. and The need for express processing is determined by two reasons. The first is that with a high level of "" interference, even with the use of EB, the operator may not notice the interference that occurs during registration. This is observed in the case of too much network frequency interference and/or its strong non-stationarity. Another example can be a sequence (pack) of radio pulses having a high-frequency filling (carrier). Of course, in the preprocessing of the data, the application My200607153) also provides a manual mode, during which it is possible to remove cardiocycles that have unwanted interference, which remained after automatic processing. - But during registration, it is not known for sure whether it will be possible to do this, that is, in other words, it is not known how many ICG ka complexes will remain, and whether the signal obtained as a result of manual processing will have the required diagnostic quality. Another reason for the need for express treatment is the low location of the heart in some patients, which

Ge) is often unknown in advance. As a result, the signal from the heart in the upper, i.e. 1st row of the grid is very weak (Fig. 7). In this case, the operator must return to the measurement mode and re-register the ICG card.

At the same time, in order to increase the useful signal in the 1st row in this useful model, it is proposed

Apply the actions described in the application Mo20040605073. After registration or re-registration, quality

ICG signals and their relative location should look similar to the magnetocardiograms shown in Figure 8.

Thus, the advantages of this approach include the fact that it is focused on the use of a relatively cheap 7-channel magneto-cardiograph and on performing examinations without a magneto-shielded room. At the same time, the main problems during registration are created by the strong magnetic pollution of modern medical facilities that take place in large cities.

The stability of the proposed method of registration of magnetocardio signals in relation to the negative influence of magnetic interference allows the examination to be carried out in the conditions of a regular clinic without the use of expensive

MEK, and thus reduces the cost of the examination, which is especially relevant in the conditions of Ukraine. 65 The specific implementation of the method in the utility model is described in detail for purposes of illustration. The specified method can be used not only when working with a magnetocardiograph, but also as part of other devices - for example,

magnetocardiographic complex or cardiomagnetic scanner. Illustrations are provided for illustrative purposes only; this method can be applied with any other software that implements the processing functions described in the patent.

It is clear that in practice, people experienced both in recording magnetocardiograms of patients in the clinic and in ICG technology in general can make some changes and modifications in the proposed actions and the sequence of their application. However, if these modifications are made without significant deviations from this utility model, they are covered by this utility model.

Claims (1)

The formula of the invention is the method of recording magnetocardiograms of the human heart based on the non-invasive method of magnetocardiography (MKG) for the purpose of diagnosing cardiac diseases, which is distinguished by the fact that an electronic balance is used, when the dynamic range of the MKG is exceeded, the signal is returned to the limits by means of zeroing, and in case of ineffectiveness of the latter - by heating (thermocycling) the magnetic field sensor(s) above the critical temperature of the superconductor, and in the presence of impulse interference, the measurement at this point is repeated; immediately after registration of all magnetocardiograms, their express processing is carried out, and if the quality of the ICG signal at some spatial point (s) is insufficient or if the signals in the upper row of the measuring grid are too weak, the magnetocardiograms are re-registered. that 2 (o) (o) s "- s - and? ime) - ime) se) 3e) 60 b5