JP3835805B2 - Cardiac magnetic field diagnostic apparatus and operating method thereof - Google Patents

Description

  The present invention relates to a cardiac magnetic field diagnostic apparatus and a three-dimensional localization evaluation method for an injured myocardium, and more specifically, calculates a three-dimensional current density distribution of a heart from a subject's cardiac magnetic field and calculates a cardiac magnetic field integral three-dimensional view (cardiac outline) The present invention relates to a cardiac magnetic field diagnostic apparatus that reconstructs a three-dimensional localization of an injured myocardial region of the heart in the same space of the subject and a method for evaluating the three-dimensional localization of the injured myocardium of the heart. .

  In the diagnosis of coronary artery disease such as myocardial infarction, diagnosis of the myocardial injury site is important. This is because the lesion site of the coronary artery can be estimated by determining the location of the myocardial lesion site.

The following methods are used as conventional methods for diagnosing myocardial injury. For example, nuclear medicine methods using single photon such as Thallium-201 and Tc-99m tetrofosmin, and radioisotopes (RI) such as ¹⁸ F-FDG and NH3 are regarded as golden standards.

  On the other hand, evaluation of myocardial injury by contrast echocardiography using a contrast agent and MRI using a gadolinium (Gd) contrast agent has been proposed in recent years.

  Any of these methods is a method using a contrast medium in addition to a radioisotope, an ultrasonic wave, and a magnetic resonance method, and is an invasive method for a living body.

  In addition, with the conventional diagnostic method described above, the absolute position of the myocardial injury site cannot be displayed in a three-dimensional space.

On the other hand, SQUID magnetometers using a superconducting quantum interference device (hereinafter referred to as SQUID) that can detect magnetic flux of about one billionth of the geomagnetism with high sensitivity are applied in various fields. . In particular, non-contact magnetic measurement of a human body using a SQUID magnetometer is performed in the field of biological measurement in which noninvasive measurement is strongly desired.

  In particular, due to the development of DC-SQUIDs due to recent advances in thin film element manufacturing technology, the magnetocardiogram, which is the magnetic field distribution of the heart, is measured using a SQUID magnetometer. Since the measurement of the cardiac magnetic field is not easily affected by the organ configuration of the lung or the torso shape, the cardiac magnetic field generated by the electrical phenomenon of the heart can be analyzed three-dimensionally.

  Furthermore, a method for obtaining a three-dimensional current density distribution in the myocardium from a two-dimensional magnetic field distribution of a cardiac magnetic field measured with a SQUID magnetometer has been proposed (see Patent Documents 1 to 3 and Non-Patent Documents 1 to 5).

In these methods, for example, an abnormal excitation propagation signal source is estimated based on a measured cardiac magnetic field by a current density distribution estimation method using a synthetic magnetic field analysis method (SAM). A method for assessing viable myocardium has been proposed. In addition, a method for estimating the current density distribution from the cardiac magnetic field distribution using a new spatial filter with excellent spatial resolution by the least square method by Tikhonov normalization has been proposed.
JP 2002-28143 A JP 2002-28144 A JP 2002-28145 A Kenji Nakai et al., “Analysis of infarcted and ischemic myocardium by magnetocardiography-clinical application of synthetic aperture magnetic field analysis”, Journal of the Electrocardiological Society of Japan, 2003, Vol. 23, No. 1, pp. 35-44 page Kenji Nakai et al., “Signal Source Estimation by Magnetocardiography Using Spatial Filter Method”, Journal of the ECG, 2004, Vol. 24, No. 1, pp. 59-69 Masato Yoshizawa et al., “Displaying the Current Density Distribution of the Electromagnetic Field by Expanded SAM”, Annual Meeting of the Biomagnetic Society of Japan, 2002; 15; 109 M. Yoshizawa, K. Nakai, Y. Nakamura, K. Kobayashi, Y. Uchikawa: "Current density imaging of simulated MCG signal by Modified Synthetic Aperture Magnetometry" BIOMAG 2002, 2002.8 (Germany) Kenji Nakai et al., “Clinical Application and Usefulness of Magnetocardiography”, Heart, Vol. 36, No. 7, pp. 549-555, Cardiac Editorial Board, July 15, 2004

  The following information obtained from the magnetocardiogram is considered to be effective for determining myocardial injury, particularly infarcted myocardium.

  First, the QRS wave in the magnetocardiogram reflects the electromotive force of the heart, and analysis of the QRS wave in the magnetocardiogram is important for determining myocardial injury.

  The T wave in the magnetocardiogram reflects the repolarization process of the myocardium, and analysis of the T wave vector (direction of the repolarization process) of the magnetocardiogram is important for determining myocardial injury.

  Furthermore, the dispersion of RT time in the magnetocardiogram, that is, RT dispersion (RT-dispersion) reflects the time dispersion of the repolarization of the myocardium (the time difference between the maximum and the minimum). Analysis of RT dispersion of the magnetocardiogram is important.

  Conventionally, the QRS wave, T wave vector, and RT dispersion are analyzed from the magnetocardiogram. However, since the magnetocardiogram signal is only two-dimensional information for mathematical reasons related to the inverse problem solution, the myocardial injury site Only two-dimensional relative spatial information about was obtained.

  In addition, as described above, a method for obtaining a three-dimensional current density distribution in the myocardium from a cardiac magnetic field distribution using a spatial filter has been proposed (see Patent Documents 1 to 3 and Non-Patent Documents 1 to 5). Since the three-dimensional spatial recognition in the heart of the same case is impossible, it is impossible to determine the localization of the injury site in the absolute three-dimensional space.

  An object of the present invention is to enable the construction of a three-dimensional view of the heart from the current density distribution in the myocardium obtained by cardiac magnetic field measurement and to evaluate the three-dimensional localization of the damaged myocardium in the constructed three-dimensional space. It is an object of the present invention to provide a cardiac magnetic field diagnostic apparatus that enables the above.

  Another object of the present invention is to make it possible to construct a three-dimensional view of the heart from the current density distribution in the myocardium determined by cardiac magnetic field measurement, and to three-dimensional localization of the damaged myocardium in the constructed three-dimensional space. It is an object of the present invention to provide a method for evaluating the three-dimensional localization of an injured myocardium that enables evaluation of

  According to one aspect of the present invention, a cardiac magnetic field diagnostic apparatus for evaluating the three-dimensional localization of an injured myocardium is a two-dimensional corresponding to a plurality of coordinates by non-contact magnetic measurement at a plurality of coordinates on the chest of a subject. Cardiac magnetic field distribution measuring means for generating cardiac magnetic field distribution data, current density data generating means for generating three-dimensional current density distribution data in the myocardium of the subject based on the generated two-dimensional cardiac magnetic field distribution data, and three-dimensional current Based on the density distribution data, a heart 3D diagram construction means for constructing a cardiac magnetic field integral 3D diagram showing the outline of the heart, and on the basis of the 3D current density distribution data, data representing the 3D localization of the damaged myocardium of the heart Injury myocardium data generation means to be generated, and image reconstruction means for reconstructing the three-dimensional localization of the damaged myocardium in the same space as the constructed cardiac magnetic field integral three-dimensional view.

  Preferably, the injured myocardial data generation means obtains a QRS difference between the average data of the QRS wave three-dimensional current density distribution data obtained from a plurality of healthy subjects and the three-dimensional current density distribution data of the subject QRS wave. Difference calculation means and drawing data generation means for generating data for drawing the three-dimensional localization of the damaged myocardium based on the obtained QRS difference.

  Preferably, the difference calculating means for obtaining the QRS difference is obtained by an integrating means for obtaining an integral value over the period of the QRS wave of the three-dimensional current density distribution data at each of the three-dimensional coordinates of the subject's chest, and the integrating means. Data holding means for obtaining and holding an average value of integral values over a period of QRS waves of a plurality of healthy subjects, and an average value of integral values of healthy subject's three-dimensional current density distribution data at each of the three-dimensional coordinates of the chest And calculating means for obtaining a difference between the integrated value of the three-dimensional current density distribution data of the subject as a QRS difference.

  Preferably, the drawing data generating unit is configured to color a point corresponding to each coordinate with a predetermined color based on a QRS difference value at each coordinate of the three-dimensional coordinate, and to each coordinate of the three-dimensional coordinate. Means for linearly interpolating between corresponding points, and means for perspective projection of the linearly interpolated three-dimensional coordinate space.

  Preferably, the drawing data generation unit sets the transparency of the color of each coordinate according to the magnitude of the QRS difference.

  Preferably, the injured myocardial data generating means includes a vector angle calculating means for obtaining an angle of a current vector from the T-wave three-dimensional current density distribution data of the subject, and an injured myocardium based on the obtained T-wave current vector angle. Drawing data generating means for generating data for drawing the three-dimensional localization.

  Preferably, the vector angle calculation means includes a first integration means for obtaining an integral value over the period of the T wave of the X component of the three-dimensional current density distribution data at each of the three-dimensional coordinates of the subject's chest, and the subject's chest Second integration means for obtaining an integral value over the period of the T wave of the Y component of the three-dimensional current density distribution data at each of the three-dimensional coordinates, and the three-dimensional current density distribution at each of the three-dimensional coordinates of the chest Computing means for obtaining the angle of the current vector from the ratio of the integral values of the X component and Y component of the data.

  Preferably, the drawing data generating unit is configured to color a point corresponding to each coordinate with a predetermined color based on the angle of the current vector at each coordinate of the three-dimensional coordinate, and to each coordinate of the three-dimensional coordinate. Means for linearly interpolating between corresponding points and means for perspective projection of the linearly interpolated three-dimensional coordinate space.

  Preferably, the drawing data generation unit sets the transparency of the color of each coordinate according to the magnitude of the angle of the current vector.

  Preferably, the injured myocardial data generating means is based on time dispersion calculating means for obtaining RT dispersion, which is a dispersion of RT time, from the three-dimensional current density distribution data of the QRS-T wave of the subject, and the obtained RT dispersion. And drawing data generation means for generating data for drawing the three-dimensional localization of the damaged myocardium.

  Preferably, the time distribution calculating means obtains an absolute value of a difference between the maximum value and the minimum value of the RT time as RT dispersion from the three-dimensional current density distribution data at each of the three-dimensional coordinates of the subject's chest. Including.

  Preferably, the drawing data generation means corresponds to means for coloring a point corresponding to each coordinate with a predetermined color based on RT dispersion at each coordinate of the three-dimensional coordinates, and to each coordinate of the three-dimensional coordinates. Means for linearly interpolating between the points to be performed, and means for perspective projection of the linearly interpolated three-dimensional coordinate space.

  Preferably, the drawing data generation means sets the transparency of the color of each coordinate according to the size of the RT dispersion.

  Preferably, the three-dimensional heart diagram constructing means is an integrated value over a predetermined period of the three-dimensional current density distribution data at each coordinate of the three-dimensional coordinates of the subject's chest or the three-dimensional energy density data obtained by squaring the three-dimensional current density distribution data. Integration means for determining the maximum value, a maximum value determination means for determining the maximum value of the integral values at each coordinate, a cube setting means for dividing the three-dimensional coordinates of the chest into a set of a plurality of cubes, and a maximum integral value Threshold setting means for setting a threshold based on the threshold, means for determining the magnitude of the integrated value of coordinates corresponding to each vertex of each cube with respect to the set threshold, and a plurality of cubes Image generating means for generating, as a cardiac magnetic field integral three-dimensional view, an image for displaying a determination result of the magnitude of the integral value in the set.

  Preferably, the image generation means includes, for each of the plurality of cubes, means for calculating the number of vertices for which the integral value of the corresponding coordinates among the eight vertices constituting each cube is greater than a threshold value; Means for drawing polygons connecting vertices larger than the threshold in a predetermined manner according to the number of vertices greater than the threshold, and arranging a plurality of cubes in the three-dimensional coordinate space of the chest Means for perspective projection of the drawn polygon, and a set of polygons of each cube obtained by the perspective projection constitutes a cardiac magnetic field integral three-dimensional view.

  According to another aspect of the present invention, a method for evaluating the three-dimensional localization of an injured myocardium includes a two-dimensional cardiac magnetic field distribution corresponding to a plurality of coordinates by non-contact magnetic measurement at a plurality of coordinates on a subject's chest. A step of generating data, a step of generating three-dimensional current density distribution data in the myocardium of the subject based on the generated two-dimensional cardiac magnetic field distribution data, and a contour of the heart based on the three-dimensional current density distribution data A step of constructing a cardiac magnetic field integral three-dimensional diagram to be shown; a step of generating data representing three-dimensional localization of an injured myocardium of the heart based on the three-dimensional current density distribution data; and the same as the constructed cardiac magnetic field integral three-dimensional diagram Reconstructing the three-dimensional localization of the damaged myocardium in the space.

  Preferably, the step of generating data representing the three-dimensional localization of the injured myocardium includes the average data of the three-dimensional current density distribution data of QRS waves obtained from a plurality of healthy subjects and the three-dimensional current of the QRS waves of the subject. A step of obtaining a QRS difference from the density distribution data; and a step of generating data for drawing a three-dimensional localization of the damaged myocardium based on the obtained QRS difference.

  Preferably, the step of obtaining the QRS difference is obtained by a step of obtaining an integral value over a period of QRS wave of the three-dimensional current density distribution data at each of the three-dimensional coordinates of the subject's chest and a step of obtaining the integral value. A step of obtaining and holding an average value of integral values over a period of QRS waves of a plurality of healthy subjects, an average value of integral values of the healthy subject's three-dimensional current density distribution data at each of the three-dimensional coordinates of the chest, and a subject And calculating the difference between the integrated value of the three-dimensional current density distribution data as the QRS difference.

  Preferably, the step of generating drawing data includes a step of coloring a point corresponding to each coordinate with a predetermined color based on a QRS difference value at each coordinate of the three-dimensional coordinate, and each of the three-dimensional coordinates. Linear interpolation between points corresponding to the coordinates, and perspective projection of the linearly interpolated three-dimensional coordinate space.

  Preferably, the step of generating drawing data includes the step of setting the transparency of the color of each coordinate according to the magnitude of the QRS difference.

  Preferably, the step of generating data representing the three-dimensional localization of the injured myocardium includes the step of obtaining the angle of the current vector from the three-dimensional current density distribution data of the T wave of the subject, and the obtained current vector angle of the T wave. And generating data for rendering the three-dimensional localization of the damaged myocardium.

  Preferably, the step of obtaining the vector angle includes the step of obtaining an integral value over the period of the T wave of the X component of the three-dimensional current density distribution data at each of the three-dimensional coordinates of the subject's chest, and the three-dimensional of the subject's chest. Obtaining an integral value over the period of the T wave of the Y component of the three-dimensional current density distribution data at each of the coordinates; and the X component and the Y component of the three-dimensional current density distribution data at each of the three-dimensional coordinates of the chest Obtaining the angle of the current vector from the ratio of the integral values of

  Preferably, the step of generating drawing data includes the step of coloring a point corresponding to each coordinate with a predetermined color based on the angle of the current vector at each coordinate of the three-dimensional coordinate, and each of the three-dimensional coordinates. Linear interpolation between points corresponding to the coordinates, and perspective projection of the linearly interpolated three-dimensional coordinate space.

  Preferably, the step of generating drawing data includes the step of setting the transparency of the color of each coordinate according to the magnitude of the angle of the current vector.

  Preferably, the step of generating data representing the three-dimensional localization of the injured myocardium is obtained by calculating an RT dispersion that is a dispersion of RT time from the three-dimensional current density distribution data of the QRS-T wave of the subject. Generating data for rendering the three-dimensional localization of the damaged myocardium based on the RT dispersion.

  Preferably, in the step of obtaining the RT dispersion, the absolute value of the difference between the maximum value and the minimum value of the RT time is obtained as the RT dispersion from the three-dimensional current density distribution data at each of the three-dimensional coordinates of the subject's chest. Includes steps.

  Preferably, the step of generating the drawing data includes coloring a point corresponding to each coordinate with a predetermined color based on RT dispersion at each coordinate of the three-dimensional coordinate, and each coordinate of the three-dimensional coordinate. Linearly interpolating between points corresponding to, and perspective projection of the linearly interpolated three-dimensional coordinate space.

  Preferably, the step of generating drawing data includes the step of setting the transparency of the color of each coordinate according to the magnitude of the RT dispersion.

  Preferably, the step of constructing the cardiac magnetic field integral three-dimensional view is a predetermined one of the three-dimensional current density distribution data obtained by squaring the three-dimensional current density distribution data or the three-dimensional current density distribution data at each of the three-dimensional coordinates of the subject's chest. A step of obtaining an integral value over a period, a step of obtaining a maximum value of integral values at each coordinate, a step of dividing the three-dimensional coordinate of the chest into a set of a plurality of cubes, and a maximum value of the integral value A step of setting a threshold value, a step of determining a magnitude of an integral value of coordinates corresponding to each vertex of each cube with respect to the set threshold value, and a judgment of a magnitude of the integral value in a set of a plurality of cubes Generating an image displaying the result as a cardiac magnetic field integral three-dimensional view.

  Preferably, the step of generating the image includes, for each of the plurality of cubes, calculating the number of vertices whose integrated value of the corresponding coordinates among the eight vertices constituting each cube is greater than a threshold value; Drawing polygons that connect vertices greater than the threshold in a predetermined manner according to the number of vertices whose integral value is greater than the threshold, and arranging a plurality of cubes in the three-dimensional coordinate space of the chest And a step of performing perspective projection of the drawn polygon, and a set of polygons of each cube obtained by the perspective projection constitutes a cardiac magnetic field integral three-dimensional view.

  As described above, according to the present invention, from the three-dimensional current density distribution of the subject's chest, the three-dimensional data of the relative display of the damaged myocardial region, such as QRS difference, T-wave vector, or RT dispersion, is performed. A 3D display is obtained, and the 3D current density distribution of the same subject is reconstructed from a 3D heart contour map constructed separately, thereby enabling an absolute 3D space display of the injured myocardial region in the heart non-invasively. This makes it possible to determine the location of myocardial injury in diagnosis of heart disease in hospitals and emergency rooms.

  In particular, the present invention provides a useful technique for the diagnosis of acute coronary syndrome (acute myocardial injury associated with the collapse of coronary atheroma), evaluation of coronary artery bypass surgery and coronary angioplasty using a catheter. It is.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

[Embodiment 1]
The first embodiment of the present invention enables the determination of the three-dimensional spatial localization of the myocardial injury site by enabling the three-dimensional display of the QRS difference of the magnetocardiogram.

  FIG. 1 is a waveform diagram showing an actual waveform of a magnetocardiogram. The principle of the first embodiment of the present invention will be described with reference to FIG.

  In the actual waveform of the magnetocardiogram of FIG. 1, the waveform of (A) is an actual waveform diagram of each channel of the cardiac magnetic field measured by, for example, a SQUID magnetometer, and the waveform of (B) is the QRS difference described below. FIG.

  As described above, the QRS wave reflects the electromotive force of the heart, and a decrease in the electromotive force of the heart is recognized at a site where myocardial injury such as myocardial infarction occurs. Therefore, the localization of the damaged myocardium can be determined by obtaining a three-dimensional current density distribution from the QRS wave equivalent portion of the magnetocardiogram signal and estimating the electromotive force of the heart.

  In Embodiment 1 of the present invention, a three-dimensional current is obtained from a portion corresponding to QRS waves of a magnetocardiogram signal of a plurality of (for example, 30) healthy persons (hereinafter, referred to as a target group) having no obvious heart disease using a spatial filter. Average data of the density distribution is obtained in advance and stored. On the other hand, a three-dimensional current density distribution is obtained using a spatial filter from a QRS wave equivalent portion of a magnetocardiogram signal of a subject (patient) having a heart disease such as myocardial infarction.

  Then, a difference (hereinafter referred to as QRS difference) between the average data of the three-dimensional current density distribution of the control group in the QRS part of the waveform and the three-dimensional current density distribution data of the subject is obtained. This represents the spatial distribution of a myocardial injury site such as myocardial infarction.

  However, the localization of the injured myocardial region within the heart can only be determined relatively only by obtaining the difference between the three-dimensional current density distribution data, and the absolute spatial localization in the heart is determined. It is not possible.

  Therefore, in the first embodiment of the present invention, it is possible to describe the outline of the heart from the three-dimensional current density distribution in the myocardium of the subject obtained by cardiac magnetic field measurement, and the control group in the QRS wave section and the above-described control group. By reconstructing the difference in the three-dimensional current density distribution between the subject and the subject within the same space of the same subject as the depicted heart outline, the injured myocardium in the absolute three-dimensional heart of the subject's heart The spatial localization of can be determined.

  A specific configuration for realizing the first embodiment of the invention will be described below.

  FIG. 2 is a block diagram showing the configuration of the cardiac magnetic field diagnostic apparatus according to Embodiment 1 of the present invention.

  Referring to FIG. 2, magnetic field distribution measuring apparatus 1 is a SQUID installed so as to perform non-contact magnetic measurement on the chest of subject 12 in a magnetically shielded room (hereinafter referred to as “MSR”) 11. A dewar 13 having a built-in magnetometer and a magnetic field distribution data calculation unit 14 provided outside the MSR 11 are provided. The magnetic distribution data calculation unit 14 may be provided in the MSR 11.

  The dewar 13 is filled with liquid helium to form a low-temperature environment in which superconductivity occurs. A SQUID magnetometer composed of a detection coil made of a superconductor is housed in the dewar 13.

  FIG. 3 is a block diagram showing in more detail the SQUID magnetometer 15 installed in the low temperature system in the dewar 13 in the MSR 11 shown in FIG. 2 and the computing unit 14 installed at room temperature. In addition, although FIG. 3 has illustrated the modulation | alteration magnetic flux lock (FLL) system as the calculating part 14 so that it may demonstrate below, the non-modulation system FLL is applicable similarly.

  Note that the configuration shown in FIG. 3 is a configuration for one channel for measuring magnetic field data at one point on the subject's chest. As will be described later, in the present invention, multipoint simultaneous measurement of magnetic fields at a plurality of coordinates is performed on the subject's chest. Therefore, the configuration for one channel shown in FIG. 3 is provided for a plurality of channels necessary for measurement. In the example described below, it is assumed that magnetic field measurement is performed at 64 points on the subject's chest coordinates, and the configuration of FIG. 3 for 64 channels is provided.

  Hereinafter, generation of magnetic field data by the SQUID magnetometer for one channel will be described with reference to FIG.

  First, the SQUID magnetometer 15 includes a pickup coil 16 made of a superconductor for detecting a magnetic field generated from the chest surface of the subject. When the pickup coil 16 captures the magnetic field, a current flows, and this current is transmitted to the coil 17 to generate a magnetic field in the Nb shield 20.

  As a result, a magnetic field that changes linearly with respect to this magnetic field is formed in the SQUID element 18. An appropriate bias current is passed through the SQUID element 18 and the voltage across the SQUID element 18 is detected by the amplifier of the calculation unit 14. The calculation unit 14 is installed in the Nb shield 20 so that the detected voltage does not change. In the modulation method FLL, the current flowing in the feedback coil 19 that is also used for magnetic field modulation is adjusted.

  That is, the detection of the magnetic field of the living body by this SQUID does not directly measure the generated magnetic field, but feedback is performed using a so-called zero position method so that the magnetic field in the SQUID element 18 always becomes a constant value (specifically Specifically, the current flowing through the feedback coil 19 is adjusted to control the magnetic field generated in the feedback coil 19 so that a constant magnetic field is always generated in the SQUID element 18). The calculated magnetic field is converted into an electric signal by the calculation unit 14 and output. Such a feedback method is a well-known technique generally called a flux locked loop (hereinafter referred to as FLL).

  Since such a SQUID magnetometer 15 and its calculation unit 14 are well-known techniques, further explanation is omitted.

  As described above, the configuration shown in FIG. 3 is a configuration necessary for measuring the magnetic field data for one channel, and is an electric signal indicating the magnetic field time-series data of the magnetic field measured at one point on the front of the subject's chest. Is output.

  In the present invention, as described above, many sensors (SQUID magnetometers) are arranged on the front side of the subject's chest, and the magnetic field on the front side of the chest is to be measured at multiple points. The magnetic field changes with time. For example, even during a period corresponding to one heartbeat, the magnetic field changes differently depending on the location if the measurement location is different.

  FIG. 4 is a diagram showing an example of an arrangement of a plurality of sensors (each of which is a one-channel SQUID magnetometer) on the front of the subject's chest. FIG. 5 shows a group of magnetic field time-series data indicating changes in the magnetic field in one heartbeat period, obtained from each sensor corresponding to each position of the plurality of sensors in FIG.

  The data output from the magnetic field distribution measuring apparatus 1 shown in FIG. 2 is a group of magnetic field time-series data corresponding to a plurality of measurement positions (coordinates) as shown in FIG. 5, but paying attention to a specific time. Taking these one group of magnetic field time-series data, it is difficult to represent the actual state of the mountain valley that shows the distribution of the magnetic field strength at a certain time on the front of the chest that is the object of measurement. Therefore, magnetic field distribution data expressed by a contour map like the atmospheric pressure of the weather map can be obtained. Also in this sense, the data output from the magnetic field distribution measuring device 1 can be understood as magnetic field distribution time series data on the front surface of the chest.

  Such a group of magnetic field time-series data output from the magnetic field distribution measuring apparatus 1, that is, magnetic field distribution time-series data is given to the arithmetic unit 2 in FIG. This computing device 2 functions by software to determine the electrical activity in the chest at that moment, for example, the current density in the chest that flows at that moment, based on the magnetic field distribution data at a certain time.

  In addition, the calculation device 2 stores data of the calculation result in the storage device 22 as necessary.

  From the magnetic field distribution time-series data generated by the magnetic field distribution measuring apparatus 1, information on the three-dimensional electrical activity in a part of the human body to be measured (in this invention, the heart), for example, the current density distribution flowing through the part. A method obtained by the arithmetic device 2 will be described.

  FIG. 6 is a diagram schematically illustrating a method for obtaining such a current density. In the method described below, if a current sensor (virtual sensor) is provided in a specific part of the human body to be analyzed, the current is supposed to be calculated indirectly. Is. For this reason, the current output of the virtual sensor can be obtained by multiplying the magnetic field time-series data obtained from all the sensors (SQUID magnetometers) installed on the front surface of the human chest by taking a sum of the coefficients. Then, how to obtain this coefficient is a central issue in this calculation.

  Hereinafter, the method for obtaining the current density will be described in more detail with reference to FIG. First, it is assumed that a total of N magnetic field sensors are arranged on the human body surface (front surface of the chest). On the other hand, the human body (chest, particularly heart) to be analyzed is regarded as a collection of voxels, each of which is a small block. Here, the total number of voxels is M.

The magnetic field time series data obtained from each sensor j is Bj (t), and each sensor output (Bj (t
Β _ij is the spatial filter coefficient of voxel i corresponding to).

Here, when it is assumed that the voxel i has a virtual current sensor, if the virtual sensor output corresponding to the current density obtained from the virtual current sensor is S _i (t), S _i (t) is expressed by the following equation. Defined.

Therefore, if the spatial filter coefficient β _ij is determined, the current density in each voxel i can be obtained, and the three-dimensional current density distribution in the entire analysis target can be obtained.

As a method for setting the above-described spatial filter coefficient β _ij so as to have a sensitive sensitivity only for the distribution current of the corresponding voxel i, various methods such as the above-described SAM and MUSIC (Multiple Signal Classification) are used. be able to. SAM and MUSIC have been researched and developed in fields such as radar and sonar, and their methods are well known.

  The virtual sensor output calculated in real time for each voxel obtained using the spatial filter coefficient by the SAM or MUSIC technique has an advantage of having a very high real-time property.

  The SAM and MUSIC technologies are well known, and the algorithm for obtaining the spatial filter coefficients using these methods is extremely complicated. Therefore, detailed description thereof is omitted here, but the SAM is Proceedings published in 1999. Detailed explanation on “Functional Neuroimaging by Synthetic Aperture Magnetometry (SAM)” by Robinson SE and Vrba J on pages 302 to 305 of “Reent Advances in Biomagnetism” of the 11th International Conference on Biomagnetism (Tohoku University Press) Has been. MUSIC is described in detail on pages 117 to 119 of “Neuromagnetic Science: SQUID Measurement and Medical Application” (Ohm Co., Ltd.) by Hiroshi Hara and Shinya Kuriki, published on January 25, 1997. .

  In this way, the arithmetic device 2 generates time-series data indicating the three-dimensional current density distribution in the heart to be analyzed from the magnetic field distribution data generated by the magnetic field distribution measuring device 1, and further described below. An operation for constructing a cardiac magnetic field integral 3D diagram is executed by software.

  The cardiac magnetic field integral three-dimensional map construction method of the present invention pays attention to the fact that current density basically exists only in the myocardial part, and constructs a cardiac magnetic field integral three-dimensional map and regards this as the outline of the heart.

  FIGS. 7 and 8 are flowcharts of a method for constructing a cardiac magnetic field integral three-dimensional diagram executed by software in the arithmetic unit 2 of FIG. 2, and particularly FIG. 7 is a flowchart showing a drawing process of the atrial cube. is there.

  Referring to FIG. 7, in step S1, a three-dimensional current density is calculated from the cardiac magnetic field distribution detected by the SQUID magnetometer of FIG. 2 by the method using the spatial filter described above with reference to FIG. Here, the three-dimensional current density calculated at time t with respect to the three-dimensional coordinates x, y, z of the subject's chest is assumed to be Ft (x, y, z). The data between the vertices of the three-dimensional current density is linearly interpolated.

  Next, in step S2, for each coordinate point of all combinations of the three-dimensional coordinates x, y, z, the current density over the time t1 to t2 of the P-wave atrium measured by the electrocardiograph 21 of FIG. S (x, y, z) which is an integral value of Ft (x, y, z) is obtained. Then, Smax that is the maximum value of S (x, y, z) is obtained.

  Next, steps S3, S4, and S5 represent a loop process for drawing a magnetic field integral three-dimensional view of the atrium of the heart, and the three-dimensional coordinates x0 to xmax, y0 to ymax, z0 to zmax shown in step S3. For all the combinations, the atrial 3D drawing process in step S4 is repeatedly executed until the loop relating to x, y, z is closed in step S5.

  Next, FIG. 8 is a flowchart showing a process of drawing a ventricular cube in the method for constructing a cardiac magnetic field integral three-dimensional view, which is executed subsequent to the process of FIG. Steps S6 to S9 in FIG. 8 are the same as steps S2 to S5 in FIG. 7 except that the integration time in step S6 is times t3 to t4 of the QRS wave ventricle measured by the electrocardiograph 21. The explanation will not be repeated.

  FIG. 9 is a flowchart showing processes common to the atrial cube drawing process in step S4 of FIG. 7 and the ventricular cube drawing process of step S8 in FIG. 10 to 14 are schematic diagrams conceptually showing a cubic drawing process of the atrium or the ventricle.

  The atrial three-dimensional drawing process in step S4 or the ventricular cube drawing process in step S8 will be described below with reference to FIGS.

  First, the three-dimensional space of the subject's chest is considered as a set of a plurality of cubes, and as one of them, three-dimensional coordinates S (x, y, z), S (x + 1, y, z), S (x, y + 1, z), S (x, y, z + 1), S (x + 1, y + 1, z), S (x + 1, y, z + 1), S (x, y + 1, z + 1), S (x + 1, y + 1, z + 1) Assume a cube with vertices.

  On the other hand, a threshold value is set based on the maximum value Smax of the current density obtained in step S2 of FIG. Such a threshold value is provided in order to depict an accurate heart outline in view of the presence and absence of current density in the myocardial portion.

  This threshold value is obtained by multiplying Smax by a coefficient of 0.0 to 1.0. For example, 0.666666666 is used as the initial value of the coefficient. Then, the operator of the apparatus finely adjusts this coefficient to an optimum value while visually observing a three-dimensional view of the heart outline completed as described later.

  First, in step S41 of FIG. 9, the number of points having an integrated value of current density larger than the threshold value based on Smax is counted among the eight points of the specific cube. Then, it is determined whether or not the number of such vertices is two or less (step S42). If it is 2 or less, no processing is performed.

  On the other hand, if there are more than two, it is next determined whether or not there are three (step S43). In the case of three, a triangular polygon (polygon) is drawn in step S44. That is, for example, as shown in FIG. 10, a triangular polygon connecting three vertices is drawn.

  On the other hand, if it is not three, it is next determined whether or not it is four (step S45). In the case of four, a triangular or quadrangular polygon is drawn in step S46.

  That is, for example, as shown in FIG. 11A, when the remaining three points are adjacent to each other around one point (large black circle) among the four points, a triangular polygon connecting the three points is drawn.

  For example, as shown in FIG. 11B, when four points are on the same plane, a quadrilateral polygon connecting the four points is drawn.

  For example, as shown in FIG. 11C, in the cases other than the above, four triangular polygons are drawn.

  On the other hand, if not four, it is next determined whether or not there are five (step S47). In the case of five, a triangular polygon is drawn in step S48.

  That is, for example, as shown in FIG. 12A, a triangular polygon connecting five points is drawn.

  For example, as shown in FIG. 12B, when five points are separated, a triangular polygon is drawn.

  On the other hand, if it is not five, it is next determined whether or not it is six (step S49). In the case of six, a triangular or quadrangular polygon is drawn in step S50.

  That is, for example, as shown in FIG. 13A, when two points below the threshold value are on the same side, a quadrilateral polygon is drawn.

  For example, as shown in FIG. 13B, when two points below the threshold are not on the same side, two triangular polygons are drawn.

  On the other hand, if not six, it is next determined whether or not seven (step S51). In the case of seven, a triangular polygon is drawn in step S52.

  That is, for example, as shown in FIG. 14, a triangular polygon adjacent to one point below the threshold value is drawn.

  On the other hand, if it is determined in step S51 that there are not seven, that is, eight, no processing is performed. As a result, drawing of the polygon for a specific cube ends.

  Then, the results of the cubic polygon depiction relating to the atrium repeatedly performed in steps S3 to S5 of FIG. 7 and the results of the cubic polygon depiction relating to the ventricle repeatedly performed in steps S7 to S9 of FIG. In step S10, perspective projection is performed.

  FIG. 15 is a diagram schematically showing the perspective projection in step S10. By performing perspective projection of a set of polygons showing the strength of current density distribution of each cube obtained as shown in FIGS. 10 to 14, image data of a magnetic field integral three-dimensional view of the myocardium can be obtained. Data is provided to one input of the display device 4 of FIG. 2 and is depicted on the display. As described above, since the current density basically exists only in the myocardium, the magnetic field integral three-dimensional view obtained in this way represents an outline three-dimensional view of the entire heart.

  For example, a cardiac magnetic field integral three-dimensional view (outline of the solid line on the left side of the figure shown by line a) showing the outline of the atrium as shown on the coordinates of 64 measurement points on the subject's chest in FIG. An integral three-dimensional view (a solid line frame on the right side in the drawing indicated by a line b) is drawn on the display of the display device 4.

  As described above, the final image is adjusted to an optimal state by the operator viewing the image and finely adjusting the threshold coefficient.

  Next, a method for recognizing the space of the heart outline represented by the cardiac magnetic field integral three-dimensional view obtained as described above will be described.

  That is, with reference to FIG. 2, four magnetic field coils 6 connected to the magnetic field generator 5 are installed at predetermined positions on the subject's chest. In this example, for example, the coils 6 are installed at four points of the fourth intercostal sternum right edge, the fourth intercostal sternum left edge, the fifth intercostal clavicle midline, and the xiphoid process.

  Of these four points, the three points excluding the xiphoid process are the international standard induction points of the standard 12-lead ECG, and can serve as reference points in standardizing the magnetocardiogram induction method as in the present invention. Is a point.

  And according to the predetermined signal supplied from the magnetic field generation circuit 5, each of the four coils 6 generates a magnetic field. The magnetic field generated by the four coils 6 is detected by a SQUID magnetometer built in the dewar 13.

  FIG. 16 is a diagram showing the positions of the four coils 6 on the surface of the chest of the subject on the CT image, and the four circles in the figure represent the coil positions. That is, V1 represents the chest lead from the fourth intercostal sternum right edge, V2 represents the chest lead from the fourth intercostal sternum left edge, V4 represents the chest lead from the fifth intercostal sternum, N represents a xiphoid process.

  Next, FIG. 17 is a waveform diagram showing signals from four coils on the body surface measured by a 64-channel SQUID magnetometer. In FIG. 17, 1 represents a chest lead from the right edge of the fourth intercostal sternum, 2 represents a chest lead from the left edge of the fourth intercostal sternum, and 4 represents a chest lead from the fifth intercostal sternum. N represents a xiphoid process. The position of such a coil is identified by visual observation of the waveform diagram of the operator.

  FIG. 18 is a diagram showing a state in which such four coil positions are reconstructed on the magnetocardiogram of a 64-channel SQUID magnetometer.

  Further, the operator operates an input device (not shown) while visually recognizing the spatial position of the coil from the magnetocardiogram, and as shown in FIG. For each of the four coils, positions 1, 2, 4 and N are drawn with circles.

  Here, among the four known points on the body surface of the subject (see FIGS. 16 to 18), V1, V2, and N are substantially on the same plane, but V4 varies depending on the subject, but is about 1 to 2 cm. It is deep inside. By switching the heart outline three-dimensional view displayed on the display device 4 to display in the depth direction by the processing of the arithmetic unit 2, the coil positions having such depths are also three-dimensionally drawn in the outline three-dimensional view. be able to.

  As described above, according to the present invention, the cardiac magnetic field integral three-dimensional view drawn based on the current density distribution obtained from the cardiac magnetic field distribution detected from the cardiac magnetic field by the SQUID magnetometer, that is, the outline of the heart, and the known coil position 4 Spatial positional association with a point is performed, and the rendered cardiac spatial position can be recognized.

  In particular, according to Embodiment 1 of the present invention, for the same subject, a three-dimensional view of the heart contour measured using the same measurement method at the same time and a known coil position are reconstructed in the same space. Therefore, compared with the conventional case where data obtained by another method is reconstructed at another time, there is no spatial shift, and extremely accurate heart space recognition is possible.

  If accurate spatial recognition of the heart is possible in this way, synthesis with anatomical image data such as MRI, CT, etc. becomes easy as necessary. In FIG. 2, if necessary, the anatomical image data generation device 3 indicated by a broken line includes an anatomical image data generation device 3 of the chest of the same subject imaged using another tomographic diagnosis device (not shown) such as MRI or X-ray CT. Slice image data is input.

  The anatomical image data generation device 3 processes the input slice image data, performs three-dimensional perspective transformation from a predetermined viewpoint, and generates anatomical image data. Techniques for forming a three-dimensional anatomical image from slice image data in this way are well known, and are disclosed in detail, for example, in Japanese Patent Application Laid-Open No. 11-128224 and International Publication WO98 / 15226. The details are therefore not described here.

  In this way, the anatomical image data generation device 3 generates data indicating a three-dimensional anatomical image of the chest near the heart of the same subject and supplies the data to the other input of the display device 4.

  The display device 4 shown in FIG. 2 displays a three-dimensional anatomical image of the subject's chest formed on the basis of the data from the anatomical fixed image data generation device 3. An image showing the outline of the heart formed based on the data is superimposed and displayed.

  FIG. 20 is a view obtained by combining the three-dimensional view of the heart outline and the MRI image shown in FIG. At the time of MRI measurement, the same 4 points as the above four coils on the body surface of the same subject are marked with markers, so that the composition with the heart outline is accurately performed without spatial deviation. be able to.

  In the above-described heart space recognition method, the operator estimates the positions of the four coils mounted on the body surface by visual observation from the magnitude of the magnetic field waveform of 64 channels acquired by the SQUID magnetometer, and input means. The magnetic field coil position is drawn in the same space as the three-dimensional view of the heart outline by operating, but instead of visual observation by the operator, the output of the 64-channel magnetometer is obtained by signal processing of software in the arithmetic unit 2. Needless to say, it is also possible to determine the coil position based on the waveform and to draw on the three-dimensional view of the heart.

  As described above, the arithmetic device 2 generates time-series data indicating the three-dimensional current density distribution in the heart to be analyzed from the magnetic field distribution data generated by the magnetic field distribution measuring device 1, and is shown in FIGS. The image data of the cardiac magnetic field integral three-dimensional view, that is, the heart outline three-dimensional view is generated by the processing. Thereafter, the arithmetic device 2 performs a process of reconstructing the QRS difference of the three-dimensional current density in the heart outline solid diagram thus obtained.

  In other words, in Embodiment 1 of the present invention, it is possible to estimate the damaged myocardial region by drawing the QRS difference by three-dimensional current density analysis and combining it with the three-dimensional heart outline obtained as described above. To do.

  21 and 22 are flowcharts of the QRS difference three-dimensional distribution display method executed by software in the arithmetic device 2 of FIG.

  Referring to FIG. 21, in step S11, a cardiac magnetic field waveform is generated by detecting the cardiac magnetic field of the subject using the SQUID magnetometer of FIG.

  Next, in step S12, an electrocardiogram R trigger by the electrocardiograph 21 in FIG. 2 is used to obtain an averaged waveform of the magnetocardiogram signals (FIGS. 4 and 5) for the subject's 64 channels, and a spatial filter is applied thereto. Then, a three-dimensional current density distribution is detected. Here, the three-dimensional current density at time t of the subject is assumed to be Ft (x, y, z).

  In particular, when the subject is a healthy person who constitutes a control group (for example, 30 healthy people), a spatial filter is applied to the 64-channel magnetocardiogram signal average waveform of each subject (healthy person) to obtain a three-dimensional current. Detect density distribution. Then, the average of the three-dimensional current densities at time t of all the subjects (healthy persons) constituting the control group is stored in the storage device 22 of FIG. 2 as Ct (x, y, z).

  Next, steps S13, S14, and S15 represent a loop process for obtaining an integral value of the three-dimensional current density distribution, and all of the three-dimensional coordinates x0 to xmax, y0 to ymax, z0 to zmax shown in step S13. For the combinations, the process of step 14 is repeatedly executed until the loop relating to x, y, z is closed in step S15.

  That is, in step S14, the three-dimensional current density Ft at time t of the subject over the interval corresponding to the heart region where the three-dimensional current density distribution should be compared between the control group (healthy person) and the subject. (X, y, z) and the respective integrated values of the three-dimensional average current density Ct (x, y, z) at time t of the control group stored in the storage device 22 are obtained, and S (x, y, z z) and SC (x, y, z).

  Note that the initial value of the interval to be compared is set between QRS. Between QRS corresponds to the ventricle in the heart outline. Therefore, between the initial values QRS means a comparison of the three-dimensional current density distribution in the ventricle between the subject and the average of healthy subjects. By changing such a comparison interval, it is possible to compare three-dimensional current density distributions at sites other than the ventricle.

  Next, in step S16, the maximum value of S (x, y, z) at each point of the three-dimensional coordinates is Smax, and the maximum value of SC (x, y, z) at each point of the three-dimensional coordinates is SCmax. To do.

  Next, in step S17 of FIG. 22, the integral value S and the integral value SC are subtracted as shown in the following equation at all points of the three-dimensional coordinates, and the result is defined as D (x, y, z). .

D (x, y, z) = SC (x-cx, y-cy, z-cz) * Smax / SCmax-S (x, y, z)
Here, cx, cy, and cz are arbitrary values for correcting the spatial information. That is, the measurement space is basically the same between the measurement of the subject and the measurement of the healthy person, but the position of the heart may be shifted due to the posture on the bed or the like. It is corrected with these values cx, cy, cz.

  Next, in step S18, the maximum value of D (x, y, z) at each point of the three-dimensional coordinates is set to Dmax.

  Next, steps S19, S20, and S21 represent a loop process for drawing a QRS difference. For all combinations of the three-dimensional coordinates x0 to xmax, y0 to ymax, z0 to zmax shown in step S19, steps are performed. The QRS difference drawing process in step 20 is repeatedly executed until the loop regarding x, y, z is closed in S21.

  FIG. 23 is a schematic diagram conceptually showing the QRS difference drawing process in step S20 of FIG. Referring to FIG. 23A, for each point of the three-dimensional coordinates, blue when D (x, y, z) is positive, red when negative, and linearly with respect to each point. Draw with coloring. In FIG. 23A, it is assumed that the upper two points are colored in red and the lower two points are colored in blue. In FIG. 23, for convenience, it is represented by black and white shading.

  Next, referring to FIG. 23B, transparency (0.0 to 1.0) according to the following equation is given to each point, and linear interpolation of colors is performed between the points. That is, the transparency is expressed by the following equation.

Transparency = (| D (x, y, z) | −threshold) ÷ (Dmax−threshold)
As described above, coordinate points with a negative QRS difference D (x, y, z) are displayed in blue. In the case of myocardial injury, due to a decrease in electromotive force of the myocardium, the current density distribution decreases compared to the average data of the control group (healthy person), and the myocardial injury site is displayed in blue. That is, according to the above transparency formula, the blue density is determined by the value of the QRS difference D (x, y, z) with respect to the maximum value Dmax of the QRS difference.

  In the example of FIG. 23B, the color is colored red toward the upper side of the square surrounded by the four points at the center and blue toward the lower side, and is linearly interpolated between them.

  Next, all the results of the QRS difference drawing process repeatedly performed in steps S19 to S21 in FIG. 22 are combined, and the perspective projection is performed in step S22 in FIG. The image data of the QRS difference of the myocardium can be obtained by perspective projection of the display set of the color indicating the magnitude of the QRS difference obtained as shown in FIG. 23. This image data is shown in FIGS. It is reconstructed in the computing device 2 and displayed on the display of the display device 4 in the same space as the contour map of the heart obtained in the process 15.

  FIG. 24 is a diagram illustrating an example of a QRS difference in a healthy person, and FIG. 25 is a diagram illustrating an example of a QRS difference in a patient. 24 and 25, (A) shows the magnetocardiogram signal waveform of the subject (FIG. 24 is a healthy person, FIG. 25 is a heart disease patient), and (B) is the corresponding QRS difference in the heart contour diagram. 3D display.

  In FIG. 24, no QRS difference is found between healthy individuals in the heart.

  On the other hand, in FIG. 25, the QRS difference is displayed in blue at a myocardial injury site (rear side wall) such as a myocardial infarction site, indicating a decrease in current density distribution, that is, a decrease in electromotive force (injured myocardium). In the reconstructed images of FIG. 24 and FIG. 25, the blue density is replaced with the black and white gradation.

  As described above, according to the first embodiment of the present invention, a 3D stereoscopic display of a QRS difference that relatively displays an injured myocardial region is obtained, and the heart is reconstructed with a separately constructed heart outline stereoscopic view. It is possible to display an absolute three-dimensional space of the injured myocardial region in the region, and to determine the location of the myocardial injury in the diagnosis of heart disease in a hospital or an emergency room.

[Embodiment 2]
The second embodiment of the present invention makes it possible to determine the three-dimensional spatial localization of the myocardial injury site by enabling the three-dimensional display of the T wave vector of the magnetocardiogram. Hereinafter, the principle of the second embodiment of the present invention will be described.

  Referring to FIG. 1 again, the actual waveform of the cardiac magnetic field in FIG. 1A includes a T wave, and as described above, the T wave reflects the myocardial repolarization process (particularly the direction of repolarization). . In a healthy person, the current vector of the QRS wave and the current vector of the T wave are in the same direction (approximately 45 degrees on average for healthy persons).

  On the other hand, when the myocardium is injured, the current vector of the T wave changes in various ways, and particularly in the infarcted myocardium, it faces the opposite direction (usually minus 180 degrees). Therefore, the injured myocardium can be determined by obtaining a three-dimensional current density distribution from the portion corresponding to the T wave of the magnetocardiogram signal and estimating the current vector angle of the T wave.

  FIG. 26 is a diagram showing the relationship between the magnetocardiogram signal and the current vector. FIG. 26A shows a magnetocardiogram waveform of 64 channels, in which there are a waveform in which the T-wave portion of each channel is a peak and a waveform in which a valley is formed. Corresponding to such a cardiac magnetic field waveform, a current vector as shown by an arrow in FIG.

  In Embodiment 2 of the present invention, a three-dimensional current vector is obtained using a spatial filter from the portion corresponding to the T wave of the subject's magnetocardiogram signal. Then, the spatial distribution of the myocardial injury site is represented by performing display according to the current vector angle obtained from the ratio of the x component and the y component of the current vector in the xy plane (the direction of the current vector is displayed in color). Can do.

  However, only by determining the angle of the three-dimensional current vector, the localization of the injured myocardial region in the heart can only be determined relatively, and determining the absolute three-dimensional spatial localization in the heart Can not.

  Therefore, in the second embodiment of the present invention, it is possible to describe the outline of the heart from the three-dimensional current density distribution in the myocardium of the subject obtained by cardiac magnetic field measurement, and the current vector of the subject in the T wave can be described. By reconstructing the angle in the same space of the same subject as the depicted heart outline, it is possible to determine the spatial localization of the damaged myocardium in absolute three dimensions in the subject's heart It is a thing.

  Hereinafter, a specific configuration and operation for realizing the second embodiment of the present invention will be described.

  The hardware configuration of the second embodiment of the present invention is the same as that of the first embodiment shown in FIG.

  First, in the arithmetic device 2 of FIG. 2, the method for constructing the heart outline solid diagram described in relation to FIG. 7 to FIG. 15 is executed, and the heart outline solid diagram shown in FIG. 19 is obtained. The process has already been described in detail and will not be repeated here.

  Next, the arithmetic unit 2 performs a process of reconstructing the three-dimensional current density in the heart outline figure obtained in this way.

  That is, in the second embodiment of the present invention, a T-wave vector (especially the angle of the current vector) is drawn in color by three-dimensional current density analysis, and synthesized with the heart outline three-dimensional view obtained as described above. This makes it possible to estimate the injured myocardial region.

  27 and 28 are flowcharts of a T-wave vector three-dimensional distribution display method (hereinafter referred to as T-CAD method) executed by software in the arithmetic unit 2 of FIG.

  Referring to FIG. 27, in step S61, a cardiac magnetic field waveform is generated by detecting the cardiac magnetic field of the subject using the SQUID magnetometer of FIG.

  Next, in step S62, the magnetocardiogram signals (FIGS. 4 and 5) for the 64 channels of the subject are averaged by the electrocardiogram R wave trigger by the electrocardiograph 21 of FIG. 2, and the addition as shown in FIG. 29 is performed. Find the average waveform. In the addition average waveform shown in FIG. 29, the time when the addition value in the latter half is the maximum, that is, the time at the peak of the gentle mountain (T wave) is Tpeak.

  Next, in step S63, a spatial filter is applied to the addition average waveform of the magnetocardiogram signals for 64 channels obtained in step S62 to detect a three-dimensional current density distribution. Here, the three-dimensional current density at time t of the subject is assumed to be Ft (x, y, z). If the x component is FXt (x, y, z) and the y component is FYt (x, y, z), the following relationship is established.

  That is, the square of Ft (x, y, z) is the square of FXt (x, y, z) + the square of FYt (x, y, z).

  Next, steps S64, S65, and S66 represent a loop process for obtaining an integral value of the three-dimensional current density distribution, and all of the three-dimensional coordinates x0 to xmax, y0 to ymax, and z0 to zmax shown in step S64. For the combinations, the process of step 65 is repeatedly executed until the loop relating to x, y, z is closed in step S66.

  That is, in step S65, the three-dimensional current density Ft (x, y, x) at the time t of the subject over the interval corresponding to the T wave, that is, over the period of Tpeak-50ms to Tpeak + 50ms centering on Tpeak. z), the x component FXt (x, y, z), and the y component FYt (x, y, z), respectively, are obtained as integral values, and S (x, y, z), SX (x, y, z) are obtained. ), SY (x, y, z). Note that 50 ms is an initial value and is an adjustable value.

  Next, in step S67, the maximum value of S (x, y, z) at each point of the three-dimensional coordinates is set to Smax.

  Next, steps S68, S69, and S70 represent a loop process for drawing a three-dimensional distribution display (T-CAD) of a T wave vector, and the three-dimensional coordinates x0 to xmax and y0 to ymax shown in step S68. , Z0 to zmax, the T wave vector distribution drawing process of step 69 is repeatedly executed until the loop relating to x, y, z is closed in step S70.

  FIG. 30 is a schematic diagram conceptually showing the T-wave vector distribution drawing process in step S69 of FIG. Referring to FIG. 30A, the angle of the T-wave current vector is calculated by the following equation based on the ratio between the x component and the y component of the current vector for each point of the three-dimensional coordinates.

arctan (SY (x, y, z) ÷ SX (x, y, z))
Here, with red = −135 degrees, green = −45 degrees, and blue = 45 degrees, each point is linearly colored and drawn according to the angle of the T-wave current vector. In FIG. 30A, it is assumed that the upper two points are colored light blue and the lower two points are colored dark blue. In FIG. 30, for the sake of convenience, black and white shades are used.

  Next, referring to FIG. 30 (B), each point is given transparency (0.0 to 1.0) according to the following equation according to the magnitude of the T-wave current vector. Perform linear interpolation of colors. That is, the transparency is expressed by the following equation.

Transparency = (S (x, y, z) −threshold) ÷ (Smax−threshold)
In the example of FIG. 30 (B), the color is colored so that blue goes lighter toward the upper side of the square surrounded by the four central points and darker toward the lower side, and the interpolation is linearly performed between them.

  Next, in step S71, as shown in FIG. 31, a histogram in which S (x, y, z), which is the magnitude of the current vector, is accumulated with respect to the current vector angle (0 to 360 degrees) is displayed. The histogram of FIG. 31 shows the distribution of the T-wave vector, and a healthy person shows a unimodal peak around 45 degrees.

  In Embodiment 2 of the present invention, the T wave vector of a healthy person is shown in blue (45 degrees), and in the diseased part, the T wave vector is shown in red (−180 degrees), for example.

  Next, all the results of the T-wave vector distribution drawing process repeatedly performed in steps S68 to S70 in FIG. 28 are combined, and perspective projection is performed in step S72 in FIG. By performing perspective projection of a set of color displays indicating the direction of the T-wave vector obtained as shown in FIG. 30, image data of a three-dimensional distribution of T-wave vectors of the myocardium can be obtained. It is reconstructed in the computing device 2 and displayed on the display of the display device 4 within the same space as the three-dimensional view of the heart obtained by the processing of FIGS.

  FIG. 32 is a diagram illustrating an example of a T wave vector in a healthy person, and FIG. 33 is a diagram illustrating an example of a T wave vector in a heart disease patient. 32 and 33, (A) shows a magnetocardiogram signal waveform of a subject (FIG. 32 is a healthy person, FIG. 33 is a heart disease patient), and (B) is a corresponding T-wave vector in a heart contour three-dimensional view. This is a three-dimensional display.

  FIG. 34 is a diagram for explaining the meaning of the circular graphs of FIGS. 32 (B) and 33 (B). In the circular graph of FIG. 34, healthy individuals are distributed around 45 degrees as indicated by solid arrows (in the image, they are originally displayed in blue), whereas in the case of FIG. As shown, it is distributed in the vicinity of 200 to 220 degrees (originally displayed in red on the image).

  In the healthy person in FIG. 32B, all T wave vectors are displayed in blue (corresponding to a vector angle of 45 degrees).

  On the other hand, in FIG. 33B, the myocardial injury site (rear side wall) such as a myocardial infarction site is displayed in red and green, and the angle of the T wave vector is an abnormal region (corresponding to a vector angle of 200 to 220 degrees). It shall be shown (indicating damaged myocardium). Note that the reconstructed images shown in FIGS. 32B and 33B are displayed with the black and white gradations replaced.

  As described above, in Embodiment 2 of the present invention, by obtaining a three-dimensional stereoscopic display of a T wave vector that relatively displays an injured myocardial region, and reconstructing it with a separately constructed heart outline three-dimensional view, An absolute three-dimensional space display of an injured myocardial site in the heart is possible, and the location of myocardial injury in diagnosis of heart disease in a hospital or an emergency room can be determined.

[Embodiment 3]
The second embodiment of the present invention makes it possible to determine the three-dimensional spatial localization of a myocardial injury site by enabling three-dimensional display of RT dispersion of the magnetocardiogram. The principle of the third embodiment of the present invention will be described below.

  Referring to FIG. 1 again, the actual waveform of the cardiac magnetic field in FIG. 1A includes an R wave and a T wave. As described above, the RT time, which is the interval between the R wave and the T wave, is the recurrent of the myocardium. Reflects the time of polarization. In a healthy person, the repolarization time is substantially uniform, and the temporal variation between the maximum time and the minimum time of repolarization, that is, RT dispersion is about 20 ms to 40 ms.

  On the other hand, when the myocardium is damaged, the RT dispersion, which is the time difference between the maximum time and the minimum time of repolarization, becomes a large value of 40 ms or more.

  In Embodiment 3 of the present invention, a three-dimensional current density distribution is obtained from a portion corresponding to an RT wave of a subject's magnetocardiogram signal using a spatial filter. The spatial distribution of the myocardial injury site can be represented by calculating the three-dimensional RT dispersion and displaying the time distribution three-dimensionally.

  However, the localization of the injured myocardial region in the heart can only be determined relatively only by obtaining the RT dispersion time distribution, and it is impossible to determine the absolute three-dimensional spatial localization in the heart. Can not.

  Therefore, in Embodiment 3 of the present invention, it is possible to describe the outline of the heart from the three-dimensional current density distribution in the myocardium of the subject obtained by cardiac magnetic field measurement, and the above-mentioned RT dispersion of the subject in the RT wave. Is reconstructed in the same space of the same subject as the depicted heart outline, thereby determining the absolute three-dimensional spatial location of the damaged myocardium in the subject's heart. It is something that can be done.

  The specific configuration and operation for realizing the third embodiment of the invention will be described below.

  The hardware configuration of the third embodiment of the present invention is the same as that of the first embodiment shown in FIG.

  First, in the arithmetic device 2 of FIG. 2, the method for constructing the heart outline solid diagram described in relation to FIG. 7 to FIG. 15 is executed, and the heart outline solid diagram shown in FIG. 19 is obtained. The process has already been described in detail and will not be repeated here.

  Next, the arithmetic unit 2 performs a process of reconstructing the three-dimensional current density in the heart outline figure obtained in this way.

  That is, in the third embodiment of the present invention, the time distribution of RT dispersion is drawn by color by three-dimensional current density analysis, and synthesized with the heart outline three-dimensional view obtained as described above, whereby the injured myocardium is synthesized. It is possible to estimate the part.

  FIG. 35 and FIG. 36 are flowcharts of the RT dispersion three-dimensional distribution display method executed by software in the arithmetic unit 2 of FIG.

  Referring to FIG. 35, in step S81, a cardiac magnetic field waveform is generated by detecting the cardiac magnetic field of the subject using the SQUID magnetometer of FIG.

  Next, in step S82, the electrocardiogram R wave trigger by the electrocardiograph 21 in FIG. 2 is used to average the magnetocardiogram signals (FIGS. 4 and 5) for the 64 channels of the subject, and the addition as shown in FIG. Find the average waveform. Then, an average value of the RR interval is obtained by an electrocardiogram R-wave trigger and set as the RR time.

  Further, in the addition average waveform shown in FIG. 29, the time at which the addition value in the latter half is maximized, that is, the time at the top of the T wave is obtained from, for example, visual observation of the waveform by the operator and is Tpeak.

  Next, in step S83, a spatial filter is applied to the addition average waveform of the magnetocardiogram signals for 64 channels obtained in step S82 to detect a three-dimensional current density distribution. Here, the three-dimensional current density at time t of the subject is assumed to be Ft (x, y, z).

  Next, steps S84 to S87 represent loop processing for obtaining RT dispersion, and combinations of all of the three-dimensional coordinates x0 to xmax, y0 to ymax, z0 to zmax shown in step S84 are performed in step S85. Only for the three-dimensional coordinates determined to be within the heart outline (current density exists), the process of step 86 is repeatedly executed until the loop regarding x, y, z is closed in step S87.

  In step S86, the value of dv / dt at which the slope of the T wave is maximized (T wave becomes a peak) over an interval substantially corresponding to the QRS-T wave, that is, in the period of R time +70 ms to Tpeak. (A value obtained by differentiating the current density with respect to time) is obtained, and an RT time that is an accurate interval from the top of the R wave to the peak of the T wave is obtained as P (x, y, z).

  Then, the difference time between the maximum value and the minimum value of the calculated RT time P (x, y, z) is defined as Color (x, y, z). Note that 70 ms is an initial value and is an adjustable value.

  Next, in step S88, the maximum value of P (x, y, z) at each point of the three-dimensional coordinates is set as Pmax.

  Next, steps S89, S90, and S91 represent a loop process for drawing the RT dispersion. For combinations of all of the three-dimensional coordinates x0 to xmax, y0 to ymax, and z0 to zmax shown in step S89, Until the loop regarding x, y, z is closed in step S91, the RT dispersion drawing process in step 90 is repeatedly executed.

  FIG. 37 is a schematic diagram conceptually showing the RT dispersion drawing process in step S90 of FIG. With reference to FIG. 37A, RT dispersion is calculated by the following equation for each point of the three-dimensional coordinates.

  That is, since the RT time varies depending on the heart rate, the heart rate at that time (the square root of the RR interval time) is corrected as follows.

(Color (x, y, z) -RT time) / (square root of RR interval time)
Here, with blue = 0, purple = 50, and red = 100, each point is linearly colored according to RT dispersion and drawn. In FIG. 37A, it is assumed that the upper two points are colored in red and the lower two points are colored in blue. In FIG. 37, black and white shading is shown for convenience.

  Next, with reference to FIG. 37 (B), each point is given transparency (0.0 to 1.0) according to the following equation according to the size of the RT dispersion, Perform linear color interpolation. That is, the transparency is expressed by the following equation.

Transparency = (P (x, y, z) −threshold) ÷ (Pmax−threshold)
In the example of FIG. 37 (B), it is colored so that it goes red toward the upper side of the square surrounded by the four points at the center, and becomes blue as it goes downward, and is linearly interpolated between them.

  Next, all the results of the RT dispersion drawing process repeatedly performed in steps S89 to S91 in FIG. 36 are combined, and the perspective projection is performed in step S92 in FIG. The image data of the three-dimensional distribution of the RT dispersion of the myocardium can be obtained by perspective projection of the color display set indicating the RT dispersion obtained as shown in FIG. 7 to 15 are reconstructed in the computing device 2 and displayed on the display of the display device 4 in the same space as the three-dimensional view of the heart obtained by the processing of FIGS.

  FIG. 38 is a diagram showing an example of RT dispersion in a healthy person, and FIG. 39 is a diagram showing an example of RT dispersion in a heart disease patient. 38 and 39, (A) shows a magnetocardiogram signal waveform of a subject (FIG. 38 is a healthy person, and FIG. 39 is a heart disease patient), and (B) is a corresponding RT dispersion in the heart contour diagram. This is a three-dimensional display.

  The vertical graphs in FIGS. 38 (B) and 39 (B) represent the RT dispersion time distribution (minimum 341 ms to maximum 408 ms), and are distributed within 38 ms in healthy individuals (originally on the image) On the other hand, in the case of FIG. 39B, it is as large as 67 ms (originally displayed in pink on the image).

  In the healthy person in FIG. 38B, all RT dispersions are displayed in blue.

  On the other hand, in FIG. 39B, a myocardial injury site (left ventricular side wall) such as a myocardial infarction site is displayed in pink to indicate that the RT dispersion is in an abnormal region (indicating damaged myocardium). . Note that the reconstructed images in FIGS. 38B and 39B are displayed with the black and white gradations replaced.

  As described above, in Embodiment 3 of the present invention, by obtaining a three-dimensional stereoscopic display of RT dispersion that relatively displays an injured myocardial region, and reconstructing it with a separately constructed heart outline three-dimensional view, An absolute three-dimensional space display of an injured myocardial site in the heart is possible, and the location of myocardial injury in diagnosis of heart disease in a hospital or an emergency room can be determined.

  In the above first to third embodiments, the number of channels of the SQUID magnetometer is 64. However, the number is not limited to this, and the number of coils attached to the body surface of the subject is limited to four. It is not something that can be done.

  In Embodiments 1 to 3 described above, the three-dimensional current density data is used to obtain a three-dimensional heart contour map, but instead of this, the three-dimensional energy density data is integrated. It may be configured so as to obtain a three-dimensional view of the heart. That is, assuming that the impedance of the living body is constant, the energy density data is obtained by squaring the current density data. In the processing of the flowcharts of FIGS. 7 to 9 described above, instead of the integrated value of the three-dimensional current density data, the integrated value of the three-dimensional energy density data obtained by further squaring the three-dimensional current density data may be used. A heart outline three-dimensional view can be obtained in exactly the same manner, and exactly the same effects as in the first to third embodiments described above can be obtained.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  The present invention makes it possible to determine the three-dimensional localization of an injured myocardium by noninvasive cardiac magnetic field measurement that does not burden the patient, and is suitable in the field of diagnostic imaging apparatus using cardiac magnetic field measurement. It is.

It is a figure which shows the waveform of the magnetocardiogram for demonstrating the principle of this invention. It is a schematic block diagram which shows the structure of the cardiac magnetic field diagnostic apparatus by Embodiment 1-3 of this invention. It is a block diagram which shows the detailed structure of the magnetic field distribution measuring apparatus shown in FIG. It is a figure which shows the example of an arrangement | sequence of the some magnetic field sensor on a test subject's chest front surface. It is a figure which shows the magnetic field time series data obtained from each of the some sensor of FIG. It is a figure which illustrates typically the method of calculating current density data from magnetic field time series data. It is a flowchart explaining the heart outline three-dimensional drawing creation process by Embodiment 1-3 of this invention. It is a flowchart explaining the heart outline three-dimensional drawing creation process by Embodiment 1-3 of this invention. It is a flowchart explaining the heart outline three-dimensional drawing creation process by Embodiment 1-3 of this invention. It is the model which shows notionally the drawing method of the heart outline by this invention. It is the model which shows notionally the drawing method of the heart outline by this invention. It is the model which shows notionally the drawing method of the heart outline by this invention. It is the model which shows notionally the drawing method of the heart outline by this invention. It is the model which shows notionally the drawing method of the heart outline by this invention. It is the model which shows notionally the drawing method of the heart outline by this invention. It is CT imaging image which shows the coil position on a test subject's body surface. It is a signal waveform diagram from the coil measured with the SQUID magnetometer. It is the figure which reconfigure | reconstructed the coil position on the magnetocardiogram of a SQUID magnetometer. FIG. 3 is a three-dimensional view of a heart outline obtained by the present invention. It is a figure which shows the image which reconfigure | reconstructed the heart outline solid diagram of FIG. 19 with the MRI image. It is a flowchart explaining the display process of the QRS difference by Embodiment 1 of this invention. It is a flowchart explaining the display process of the QRS difference by Embodiment 1 of this invention. It is a schematic diagram which shows notionally the QRS difference drawing process of FIG. It is a figure which shows the example of the three-dimensional display of QRS difference in a healthy person. It is a figure which shows the example of the three-dimensional display of QRS difference in a heart disease patient. It is a figure which shows the current vector measured by Embodiment 2 of this invention. It is a flowchart explaining the display process of the T wave vector by Embodiment 2 of this invention. It is a flowchart explaining the display process of the T wave vector by Embodiment 2 of this invention. It is a wave form diagram which shows the addition average waveform of a magnetocardiogram waveform. It is a schematic diagram which shows notionally the T wave vector drawing process of FIG. It is a figure which shows the histogram of angle distribution of a T wave vector. It is a figure which shows the example of the three-dimensional display of the T wave vector in a healthy subject. It is a figure which shows the example of the three-dimensional display of the T wave vector in a heart disease patient. It is a figure which shows the circular graph of angle distribution of T wave vector. It is a flowchart explaining the display process of RT dispersion by Embodiment 3 of this invention. It is a flowchart explaining the display process of RT dispersion by Embodiment 3 of this invention. FIG. 37 is a schematic diagram conceptually showing an RT dispersion drawing process of FIG. 36. It is a figure which shows the example of the three-dimensional display of RT dispersion in a healthy person. It is a figure which shows the example of the three-dimensional display of RT dispersion in a heart disease patient.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Magnetic field distribution measuring apparatus, 2 Arithmetic apparatus, 3 Anatomical image data generation apparatus, 4 Display apparatus, 5 Magnetic field generator, 6 Coil, 12 Subject, 13 Dewar, 14 Calculation part, 15 SQUID magnetometer, 16 Detection coil , 17 coil, 18 SQUID element, 19 feedback coil, 20 Nb shield, 21 electrocardiograph, 22 storage device.

Claims (30)

A cardiac magnetic field diagnostic apparatus for evaluating the three-dimensional localization of an injured myocardium,
Cardiac magnetic field distribution measuring means for generating two-dimensional cardiac magnetic field distribution data corresponding to the plurality of coordinates by non-contact magnetic measurement at a plurality of coordinates on the chest of the subject;
Current density data generating means for generating three-dimensional current density distribution data in the myocardium of the subject based on the generated two-dimensional cardiac magnetic field distribution data;
Based on the three-dimensional current density distribution data, a cardiac stereogram constructing means for constructing a cardiac magnetic field integral stereogram showing the outline of the heart;
Injured myocardial data generating means for generating data representing the three-dimensional localization of the injured myocardium of the heart based on the three-dimensional current density distribution data;
An apparatus for diagnosing cardiac magnetic field, comprising image reconstruction means for reconstructing the three-dimensional localization of the damaged myocardium in the same space as the constructed cardiac magnetic field integral three-dimensional view. The injured myocardial data generation means includes:
A difference calculating means for obtaining a QRS difference between the average data of the three-dimensional current density distribution data of QRS waves of a plurality of healthy persons obtained in advance and the three-dimensional current density distribution data of the QRS waves of the subject;
The cardiac magnetic field diagnosis apparatus according to claim 1, further comprising drawing data generation means for generating data for drawing the three-dimensional localization of the damaged myocardium based on the determined QRS difference. The difference calculation means for obtaining the QRS difference is:
Integrating means for obtaining an integrated value over a period of QRS wave of the three-dimensional current density distribution data at each of the three-dimensional coordinates of the subject's chest;
Data holding means for obtaining and holding an average value of integral values over a period of QRS waves of a plurality of healthy persons obtained by the integrating means;
The difference between the average value of the integral value of the three-dimensional current density distribution data of the healthy subject and the integral value of the three-dimensional current density distribution data of the subject at each coordinate of the three-dimensional coordinates of the chest is the QRS. The cardiac magnetic field diagnosis apparatus according to claim 2, further comprising a calculation unit that obtains the difference. The drawing data generation means includes
Means for coloring a point corresponding to each coordinate with a predetermined color based on a value of the QRS difference at each coordinate of the three-dimensional coordinates;
Means for linearly interpolating between points corresponding to the coordinates of the three-dimensional coordinates;
The cardiac magnetic field diagnostic apparatus according to claim 3, further comprising: a perspective projection method for the linearly interpolated three-dimensional coordinate space. The drawing data generation means includes
The cardiac magnetic field diagnosis apparatus according to claim 4, wherein the transparency of the color of each coordinate is set according to the magnitude of the QRS difference. The injured myocardial data generation means includes:
A vector angle calculation means for obtaining an angle of a current vector from the three-dimensional current density distribution data of the T wave of the subject;
The cardiac magnetic field diagnosis apparatus according to claim 1, further comprising drawing data generation means for generating data for drawing a three-dimensional localization of the damaged myocardium based on the obtained current vector angle of the T wave. The vector angle calculation means includes
First integration means for obtaining an integral value over the period of the T wave of the X component of the three-dimensional current density distribution data at each of the three-dimensional coordinates of the subject's chest;
Second integration means for obtaining an integral value over a period of T wave of the Y component of the three-dimensional current density distribution data at each of the three-dimensional coordinates of the subject's chest;
The heart according to claim 6, further comprising calculation means for obtaining an angle of the current vector from a ratio of an integral value of an X component and a Y component of the three-dimensional current density distribution data at each of the three-dimensional coordinates of the chest. Magnetic field diagnostic device. The drawing data generation means includes
Means for coloring a point corresponding to each coordinate with a predetermined color based on an angle of the current vector in each coordinate of the three-dimensional coordinates;
Means for linearly interpolating between points corresponding to the coordinates of the three-dimensional coordinates;
The cardiac magnetic field diagnosis apparatus according to claim 7, further comprising: a perspective projection method for the linearly interpolated three-dimensional coordinate space. The drawing data generation means includes
9. The cardiac magnetic field diagnostic apparatus according to claim 8, wherein the transparency of the color of each coordinate is set according to the magnitude of the angle of the current vector. The injured myocardial data generation means includes:
A time dispersion calculating means for obtaining RT dispersion (RT-dispersion) which is a dispersion of RT time from the three-dimensional current density distribution data of the QRS-T wave of the subject;
The cardiac magnetic field diagnosis apparatus according to claim 1, further comprising: a drawing data generation unit that generates data for drawing a three-dimensional localization of the damaged myocardium based on the obtained RT dispersion. The time distribution calculating means includes
The means for obtaining the absolute value of the difference between the maximum value and the minimum value of RT time as RT dispersion from the three-dimensional current density distribution data at each of the three-dimensional coordinates of the subject's chest. Cardiac magnetic field diagnostic device. The drawing data generation means includes
Means for coloring a point corresponding to each coordinate with a predetermined color based on the RT dispersion at each coordinate of the three-dimensional coordinates;
Means for linearly interpolating between points corresponding to the coordinates of the three-dimensional coordinates;
The cardiac magnetic field diagnostic apparatus according to claim 11, further comprising: a fluoroscopic projection of the linearly interpolated three-dimensional coordinate space. The drawing data generation means includes
The cardiac magnetic field diagnosis apparatus according to claim 12, wherein the transparency of the color of each coordinate is set according to the magnitude of the RT dispersion. The heart three-dimensional map constructing means includes:
Integration means for obtaining an integral value over a predetermined period of the three-dimensional current density distribution data at each of the three-dimensional coordinates of the subject's chest or the three-dimensional energy density data obtained by squaring the three-dimensional current density distribution data;
Maximum value determining means for obtaining a maximum value of the integral values at the respective coordinates;
Cube setting means for dividing the three-dimensional coordinates of the chest into a set of a plurality of cubes;
Threshold setting means for setting a threshold based on the maximum value of the integral value;
Magnitude judgment means for judging the magnitude of the integral value of coordinates corresponding to each vertex of each of the cubes with respect to the set threshold value;
14. The cardiac magnetic field diagnosis according to claim 1, further comprising: an image generation unit configured to generate, as the cardiac magnetic field integral three-dimensional image, an image that displays a determination result of the integral value in the set of the plurality of cubes. apparatus. The image generating means includes
Means for calculating, for each of the plurality of cubes, the number of vertices in which the integrated value of the corresponding coordinates among the eight vertices constituting each cube is greater than the threshold;
Means for drawing a polygon connecting vertices greater than the threshold in a predetermined manner according to the number of vertices with the integral value greater than the threshold;
Means for arranging the plurality of cubes in a three-dimensional coordinate space of the chest and projecting the drawn polygon through a perspective method;
The cardiac magnetic field diagnostic apparatus according to claim 14, wherein a set of polygonal polygons obtained by the perspective projection constitutes the cardiac magnetic field integral three-dimensional view. Cardiac magnetic field distribution measuring means for generating two-dimensional cardiac magnetic field distribution data corresponding to the plurality of coordinates by non-contact magnetic measurement at a plurality of coordinates on the subject's chest, and processing the generated two-dimensional cardiac magnetic field distribution data An operation method of a cardiac magnetic field diagnostic apparatus comprising a calculation means ,
The computing means is
Generating three-dimensional current density distribution data in the myocardium of the subject based on the two-dimensional cardiac magnetic field distribution data generated by the cardiac magnetic field distribution measuring means ;
Based on the three-dimensional current density distribution data, construct a cardiac magnetic field integral three-dimensional view showing the outline of the heart,
Based on the three-dimensional current density distribution data, data representing the three-dimensional localization of the injured myocardium of the heart is generated. A method for operating a cardiac magnetic field diagnostic apparatus comprising the step of reconfiguring the presence. Generating data representing the three-dimensional localization of the damaged myocardium,
The computing means is
A plurality of healthy subjects of the average data of a three-dimensional current density distribution data of the QRS wave that has been previously calculated, determined Me a QRS difference between 3-dimensional current density distribution data of the QRS wave of the subject, the more the determined was QRS difference based on, including steps of generating data for drawing a three-dimensional localization of the injury myocardial method for operating a cardiac magnetic field diagnostic apparatus according to claim 16. The step of obtaining the QRS difference includes:
The computing means is
The 3-dimensional current density determined Me an integral value over a period of QRS wave of the distribution data in each of the coordinates of three-dimensional coordinates of the chest of the subject,
An average value of integral values over a period of QRS waves of a plurality of healthy persons obtained by the step of obtaining the integral value is obtained and held , and further , the three-dimensional of the healthy person at each of the three-dimensional coordinates of the chest including steps of calculating a difference between the integrated value of the 3-dimensional current density distribution data of the average value of the integrated value of the current density distribution data subject as the QRS difference, cardiac magnetic field diagnostic apparatus according to claim 17 Operating method. The step of generating the drawing data includes
The computing means is
Based on the value of the QRS difference at each of the three-dimensional coordinates, a point corresponding to each of the coordinates is colored with a predetermined color,
Between the points corresponding to the respective coordinates of the three-dimensional coordinate linear interpolation, further comprising a steps of projecting fluoroscopy, the linear interpolation is three-dimensional coordinate space has, the cardiac magnetic field diagnostic apparatus according to claim 18 Actuation method. The step of generating the drawing data includes
The operation method of the cardiac magnetic field diagnosis apparatus according to claim 19, wherein the computing means includes a step of setting the transparency of the color of each coordinate according to the magnitude of the QRS difference. Generating data representing the three-dimensional localization of the damaged myocardium,
The computing means is
Angle determined Me current vector from the three-dimensional current density distribution data of the subject's T-wave, further based on the current vector angle of the determined T-wave, generates data for drawing a three-dimensional localization of the injury myocardial step including flop method for operating a cardiac magnetic field diagnostic apparatus according to claim 16. The step of obtaining the vector angle includes:
The computing means is
Calculated Me an integral value over a period of T wave of the X component of the three-dimensional current density distribution data in each of the coordinates of three-dimensional coordinates of the chest of the subject,
Calculated Me an integral value over a period of T wave of the Y component of the 3-dimensional current density distribution data in each of the coordinates of three-dimensional coordinates of the chest of the subject, further the three-dimensional in the respective coordinates of the three-dimensional coordinates of the chest including steps from a ratio of integral values of X and Y components of the current density distribution data determining the angle of the current vector, a method of operating a cardiac magnetic field diagnostic apparatus according to claim 21. The step of generating the drawing data includes
The computing means is
Based on the angle of the current vector at each of the three-dimensional coordinates, a point corresponding to each of the coordinates is colored with a predetermined color,
Between the points corresponding to the respective coordinates of the three-dimensional coordinate linear interpolation, further comprising a steps of projecting fluoroscopy, the linear interpolation is three-dimensional coordinate space has, the cardiac magnetic field diagnostic apparatus according to claim 22 Actuation method. The step of generating the drawing data includes
24. The operating method of the cardiac magnetic field diagnosis apparatus according to claim 23, wherein the calculation means includes a step of setting the transparency of the color of each coordinate according to the magnitude of the angle of the current vector. Generating data representing the three-dimensional localization of the damaged myocardium,
The computing means is
Subjects a QRS-T dispersion from the three-dimensional current density distribution data of RT time wave is RT-dispersion the determined eye, based on further the determined RT-dispersion, to draw a three-dimensional localization of the injury myocardial including steps of generating data, a method of operating a cardiac magnetic field diagnostic apparatus according to claim 16. The step of obtaining the RT dispersion includes
The calculating means includes a step of obtaining an absolute value of a difference between a maximum value and a minimum value of RT time as an RT dispersion from the three-dimensional current density distribution data at each of three-dimensional coordinates of the subject's chest. 26. A method of operating a cardiac magnetic field diagnostic apparatus according to claim 25. The step of generating the drawing data includes
The computing means is
Based on the RT dispersion at each of the three-dimensional coordinates, the points corresponding to the respective coordinates are colored with a predetermined color,
Between the points corresponding to the respective coordinates of the three-dimensional coordinate linear interpolation, further comprising a steps of projecting fluoroscopy, the linear interpolation is three-dimensional coordinate space has, the cardiac magnetic field diagnostic apparatus according to claim 26 Actuation method. The step of generating the drawing data includes
28. The operating method of the cardiac magnetic field diagnosis apparatus according to claim 27, wherein the calculation means includes a step of setting the transparency of the color of each coordinate according to the magnitude of the RT dispersion. Constructing the cardiac magnetic field integral stereogram comprises
The computing means is
The three-dimensional current density distribution data or determined Me an integral value over a predetermined period of the three-dimensional energy density data obtained by squaring the 3-dimensional current density distribution data in each of the coordinates of three-dimensional coordinates of the chest of the subject,
Calculated Me a maximum value among the integrated values in the respective coordinates,
Dividing the three-dimensional coordinates of the chest into a set of a plurality of cubes;
Set the threshold based on the maximum value of the integral value,
Image for the set threshold value, determines the magnitude of the integrated value of the coordinates corresponding to each vertex of each of the cube, which further displays the determination result of the magnitude of the integration value in the set of the plurality of cubes the including steps of generating as the cardiac magnetic field integral cubic diagram, a method of operating a cardiac magnetic field diagnostic apparatus according to any one of claims 16 to 28. Generating the image comprises:
The computing means is
Each each of said plurality of cubes, the integral value of the corresponding coordinates of the eight vertices of the respective cube calculates the number of larger vertices than the threshold value,
In embodiments where the integral value predetermined according to the number of larger vertices than the threshold value, and draw a polygon connecting the greater apex than the threshold, further wherein the plurality of three-dimensional coordinate space of the thorax cubes are arranged comprises steps of projecting fluoroscopy, the rendered polygon,
30. The operating method of a cardiac magnetic field diagnostic apparatus according to claim 29, wherein a set of polygonal cubes obtained by the calculation means by the perspective projection constitutes the cardiac magnetic field integral three-dimensional view.