FI98267C - Device for measuring bioelectrical sources of the heart and nervous system by combining information from measurements of the electric and magnetic fields generated by their bioelectrical activity - Google Patents

Description

98267 DEVICE FOR MEASURING BIO-ELECTRICAL SOURCES CONSTRUCTED BY THE HEART AND NERVOUS SYSTEM BY COMBINING THE MEASUREMENT OF THE ELECTRICAL AND MAGNETIC FIELD GENERATED BY THEIR BIODELICAL ACTIVITIES.

The invention relates to a device with which more accurate information on the structure and operation of a bioelectric volume source can be obtained by simultaneously utilizing information obtained from measurements of the electric and magnetic fields generated by said bioelectrical operation. The device can be used to measure a bioelectrical source formed by the heart and brain.

Due to mathematical facts, only three independent bipolar 10 electrical measurements can be made from a volume source. These are orthogonal, i.e., measurements perpendicular to each other. The sensitivity of each of them is thus in the direction of the relevant component (coordinate axis) and the absolute value of the measurement sensitivity is homogeneous throughout the area of the heart, Fig. 1. At its most typical, this is realized when measuring the electrocardiogram. . rope dipole. This measurement method is called vector \ ricardiography, VKG.

• · • · ·: In a 12-lead ECG system in clinical use, measurements can also be taken in other directions • · * 1 ·? 20 than in the directions of the coordinate axes. In this case, however, at least for measurements made far enough away from the heart, all other measurements are. linear combinations of the above three measurements, and thus do not provide new information and do not improve the diagnostic capability of the method (correctly '<"· the percentage of patients diagnosed).

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Since the electric current always also generates a magnetic field, the bioelectrical action of the biological tissue also generates a biomagnetic field in addition to the bioelectrical field. The measurement of the magnetic field generated by the bioelectrical activity of the heart 5 is called the magnetocardiogram, MKG, and the measurement of the magnetic field generated by the bioelectrical activity of the brain is called the magneto-t oenke phiogram, MEG.

As with electrical measurements, only three orthogonal, i.e. perpendicular, independent bipolar measurements can be made from the volume source. These form the measurement of the magnetic dipole formed by the bioelectrical action of the volume source. The sensitivity distribution 15 of these is substantially different from the sensitivity distribution of the electronic measurement. The sensitivity distribution of the magnetic measurement is (in the case of a cylinder symmetric) throughout in a direction tangential to the axis of symmetry (coordinate axis). The absolute value of the sensitivity is 20 directly proportional to the distance from the axis of symmetry, Figure 2.

Since the measurement of a magnetic dipole also consists of three independent components, it is natural that. that magnetic measurement of a bioelectrical source provides an amount of information of the same order of magnitude as • 1 φ • · · .1 .1 information. Therefore, the number of correctly diagnosed • ♦ · • · 1 patients is of the same order of magnitude in both the MKG and the ECG, (and * · · • "MEG and EEG, respectively). ·· V 1 30 However, the sets of laws are not identical because the sensitivity distributions of the electrical and magnetic measurements: differ substantially, as illustrated in Figure 3. The large circle marked P represents the entire patient material. 98267 3 M means a group of patients of approximately the same size correctly diagnosed by a magnetically measured signal.Regions E and M partially overlap. Since this is the case of course, it is not possible to know who are the patients who have been diagnosed correctly or incorrectly by either method.

10 Already in the very beginning of biomagnetic measurements, electrical measurements of a bioelectrical source have been made at the same time as magnetic measurements. However, the information from these measurements has not been combined, but electronic measurement has either been used as a synchronization signal to average the periodic magnetic signal when measuring the magnetic field of the heart or by comparing the diagnosis or source positioning separately with the diagnosis or magnetic diagnosis. This is illustrated in Figure 4.

When the source measurement or patient diagnosis is made separately on the basis of electrical measurements on the one hand and magnetic measurements on the other, although simultaneously. It is not possible to know who they are! 25 tiles for which the diagnosis based on electronic measurement / is incorrect, but the diagnosis based on magnetic measurement • · · • · * is correct, or vice versa. As a result, magnetic measurements have not yielded better electrical accuracy than source measurements or better diagnostic capability, even if the same patient material is subject to both an electronic measurement and a diagnostic diagnosis. diagnosis based on magnetic • · · measurement.

The invention relates to the fact that since the three independent measurements used in the measurement of the electric dipole and the three independent measurements used in the measurement of the magnetic dipole are still independent of each other, a total of six independent measurements can be obtained by combining the electrical and magnetic measurements. the amount of information available. In cardiac studies, this method can be called electromagnetocardiography, EMCG.

An essential advantage of the invention is that this method can be used to combine patient materials correctly diagnosed on the basis of electrical signal measurement and magnetic signal measurement. It has been shown experimentally that in this way an improvement in diagnostic ability can be achieved in which the number of misdiagnosed patients is reduced by up to half without increasing the total number of parameters used in the diagnosis. This is illustrated in Figure 5 in the region of E&M, which covers areas E and M in total, representing the group of patients correctly diagnosed by a method combining electrically and magnetically measured signals.

The sensitivity distributions of electrical and magnetic measurement of the bioelectrical function of the brain and other tissues producing bioelectrical signals follow the appropriate. . the above-mentioned cardiac bioelectrical functions; *. 25 min related to electrical and magnetic measurement. · · * · * · Sensitivity distributions. Similarly, conclusions about the structure and function of these tissues are based on the measurement of the parameters of the curves measured from them.

i · • * • (- • ·: i What has been said above about the measurement of an electric and magnetic dipole source can also be directly applied to the measurement of higher order sources, i.e. quadrupole, • · · octupole, etc.

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Claims (2)

5 98267 PATENT CLAIM An apparatus for measuring the bioelectrical function of the heart and nervous system, comprising both means for measuring the electric field generated by the object and means for measuring the magnetic field generated by the object 5, characterized by means for storing signals from both fields in parallel as independent and independent and for selecting and calculating computer program parameters. both of these signals freely in order of precedence. L. Anordning for the production of high power and nervous system bioelectric chlorine, in which case 15 systems for the production of electrical equipment and the system for,, for the supply of magnetic equipment, are included in the system for the operation of the system. »· · * -” The external signal signal is the same as the value of the signal and the computer program is set to the external signal value * 20 parameters of the signal signal range. m · i -.1 ψ 1 • 1 «1 9 · i ·« «<* i · • · ·