JP4972443B2 - Biomagnetic field measurement device - Google Patents

Description

  The present invention relates to a magnetic field measurement using a high-sensitivity magnetometer such as a SQUID (Superconducting Quantum Interference Device) flux meter, which is a superconducting device that performs biomagnetic field measurement of a cardiac magnetic field (a magnetic field generated from the heart). More particularly, the present invention relates to a standard template waveform generation method, a standard template waveform difference generation method and display method, and a cardiac magnetic field waveform region division method.

  In the diagnosis of heart diseases such as arrhythmia and ischemic heart disease, it is very important to be able to visualize electrophysiological phenomena in the myocardium. One of the devices that visualize electrophysiological phenomena in the myocardium is a biomagnetic field measurement device. The biomagnetic field measurement apparatus can measure a weak magnetic field (hereinafter abbreviated as “cardiac magnetic field”) generated from the heart in a non-invasive and non-contact manner, and can visualize the current distribution flowing inside the myocardium using the cardiac magnetic field data.

  As a method for visualizing the intramyocardial current distribution using the biomagnetic field measuring apparatus, a current-arrow map (hereinafter abbreviated as CAM) has been developed (see, for example, Non-Patent Documents 1 and 2). CAM is a method in which a vector on a two-dimensional plane obtained from differentiation of a normal component of cardiac magnetic field data measured at each measurement point is used as an in-vivo current distribution. By calculating CAM from cardiac magnetic field data measured at the front and back of the subject, the state of myocardial excitation propagation of the entire heart can be visualized (see, for example, Non-Patent Document 3). This CAM-based analysis method of heart disease includes visualization of abnormal excitation propagation from time-series images of CAM, identification of ischemic sites using CAM of ventricular depolarization process, and clinical effectiveness. Has been reported (for example, see Non-Patent Documents 4 and 5).

  In recent years, a method of projecting a CAM on a three-dimensional heart model created from a nuclear magnetic resonance imaging image (hereinafter abbreviated as an MRI image) of each subject has been developed. A display method has been reported (for example, see Japanese Patent Application No. 2002-147051, Non-Patent Document 6).

H. Hosaka, et.al., “Visual determination of generators of the magnetocardiogram”, J. Electrocardiol., Vol. 9, pp. 426-432, 1976 T.Miyashita, et.al., “Construction of tangential vectors from normal cardiac magnetic field components”, Proc. 20th Int. Conf. IEEE / EMBS (Hong Kong), pp. 520-523, 1998 K. Tsukada, et.al., “Noninvasive visualization of multiple simultaneously activated regions on torso magnetocardiographic maps during ventricular depolarization”, J. Electrocardiol., Vol. 32, no. 4, pp. 305-313, 1999 Y. Yamada, et.al., “Noninvasive diagnosis of arrhythmic foci by using magnetocardiogram-method and accuracy of magneto-anatomical mapping system-”, J. Arrhythmia, vol. 16, no. 5, pp. 580-586, 2000 A. Kandori, et.al., “A method for detecting myocardial abnormality by using a current-ratio map calculated from an exercise-induced magnetocardiogram", Med. Biol. Eng. Comput., Vol. 39, pp. 29-34 , 2001 K. Ogata, et.al., “Visualization method of current distribution in cardiac muscle using a heart model”, Transactions of the japanese society for medical and biological engineering, vol. 41, no. 1, pp. 25-33 (2003 )

  The electrical activity of the heart is considered to be composed of the sum of electrical activity in a healthy state and the load or absence of abnormal electrical activity due to ischemia or arrhythmia.

  In the above-described conventional method, the electrical activity of the heart can be two-dimensionally or three-dimensionally imaged, but normal electrical activity and abnormal electrical activity cannot be separated and displayed or analyzed. Furthermore, there is no area display means for simply displaying an abnormal activity area.

In a typical configuration of the present invention, as an ST-T template creation means for creating a template of an ST-T component including a T wave, the waveform divided into the ST-T components of each subject is the most of the T wave. A front and rear waveform division processing means for dividing each of the two waveforms in the time zone before and after the point of time when the amplitude is large, and a waveform enlargement processing for expanding the time scale of the front waveform obtained by the front and rear waveform division processing to a constant value. First expansion processing means for performing, and second expansion processing means for performing waveform expansion processing on the back side waveform obtained by the front and rear waveform division processing using the expansion ratio used by the first expansion processing means; A waveform processing average that obtains an ST-T component template by performing an averaging process from the waveform of each connected subject, and a connection processing means for connecting the front waveform and the rear waveform after waveform expansion processing A processing means.

The cardiac magnetic field waveform is divided into three components (PQ component, QRS component, and ST-T component) divided by time width. Thereafter, the following processing is performed.
(1) The PQ component and QRS component are adjusted to the maximum data length among the data handling the data length by inserting zeros after the waveform. Further, the amplitude value of the cardiac magnetic field is normalized and calculated to be 1.
(2) The ST-T component is divided into two waveforms before and after the time of the T-wave apex. Waveform enlargement processing is performed at the first enlargement ratio so that the divided waveform of the first half part becomes 1001 ms in the time axis direction. The waveform of the second half divided by using the first enlargement ratio is enlarged in the time axis direction. Two enlarged waveforms are synthesized, and zeros are inserted after the synthesized waveforms to adjust the data length to the maximum data length among the data handling the data length. Further, the amplitude value of the cardiac magnetic field is normalized and calculated to be 1.
(3) Perform the processes (1) and (2) above on each of the cardiac magnetic field data of a plurality of healthy subjects, and perform the averaging process using each of the processed components to create a template waveform. To do.
(4) The template waveform of each component subjected to the processing in (3) is adjusted for each component by adjusting the time width and amplitude value to the average value of each cardiac magnetic field data of a plurality of healthy subjects, and the average cardiac magnetic field Create a waveform template.
(5) From the cardiac magnetic field data to be evaluated, the template waveform created in (3) is subjected to differential processing from the waveform in which the processing of (1) and (2) is performed and the data length and amplitude value are adjusted. A current distribution diagram such as a current arrow diagram is created from the waveform obtained by the difference as necessary.
(6) Cardiac magnetic field data to be evaluated or template waveforms obtained by the processes (1), (2), (3), (4) and (5) above in the measurement area. In the divided area, the features of the waveform and the current distribution are described.

The present invention has the following effects.
(1) The average magnetic field waveform and current pattern of the cardiac magnetic field can be easily grasped by the template creation means.
(2) By dividing the measurement region into six regions using the characteristics of the cardiac magnetic field, the heart's electrical activity can be simply and clearly found in each region.
(3) It is easy to grasp only abnormal electrical activity occurring in the heart by performing differential processing on the template waveform synthesized from the cardiac magnetic field waveform measured by each subject.

  FIG. 1 is a diagram illustrating a configuration example of a biomagnetic field measurement apparatus according to an embodiment of the present invention. Inside the magnetic shield room 1, a bed 7 on which a living body is mounted and a refrigerant (liquid helium or liquid nitrogen) for maintaining a superconducting quantum interference device (hereinafter referred to as SQUID) sensor in a superconducting state. ), And a gantry 3 for fixing the position of the cryostat 2 is disposed. The SQUID sensor operates as a magnetometer by a drive circuit 4 arranged outside the magnetic shield room 1, and the output of the magnetometer passes through an amplifier filter unit 5 and is converted into digital data by an analog-digital conversion circuit built in the computer 6. And stored in the computer 6. In this embodiment, the SQUID sensor using superconductivity is described. However, it is not always necessary to use a superconducting sensor, and a high-sensitivity magnetometer such as an optical pumping magnetometer can be used.

  FIG. 2 is a diagram showing an example of the arrangement of the detection coils 8 arranged inside the cryostat 2 of FIG. The detection coil 8 and the SQUID sensor are configured integrally, and in the example shown in FIG. 2, 64 detection coils 8-1 to 8-64 configured integrally with the SQUID sensor are arranged in an 8 × 8 matrix. Yes. The arrangement of the matrix shape facilitates the calculation of the current vector of the present invention. Here, in this embodiment, the current vector is calculated using a method called a current arrow diagram. The current arrow diagram is a method of calculation assuming a pseudo current vector I (Ix = dBz / dy, Iy = −dBz / dx) obtained by partial differentiation of the normal magnetic field (Bz). However, the current vector calculation method includes a minimum norm method and a method of calculating an inverse matrix of the lead field, and therefore, the arrangement as shown in FIG. 2 is not necessarily required.

A template waveform creation method will be described with reference to FIGS.
First, the main processing flow using FIG. 3 will be described. When the template start 30 is performed, the waveform is first divided 31 into three parts: a P wave, a QRS wave, and an ST-T wave. A template is created with three parts, each P wave, QRS wave, and ST-T wave. The waveform from the P wave to the beginning of the Q wave is called the PQ template 35, and only the QRS wave part is the QRS template. A waveform from the end point of the S wave to the end of the T wave is called an ST-T template 33. For these three templates, the method for creating the PQ template and the QRS template is described with reference to FIGS. 4 and 5, and the method for creating the ST-T template is described with reference to FIGS. Using the created three templates, processing is performed in accordance with the time width and magnetic field strength (value shown in FIG. 14) obtained from the average value of normal cardiac magnetic field data of many subjects (here, 464 people). Either of these processes may be performed first. In FIG. 3, the time width adjustment process of process 36 is performed in advance, and then the process of adjusting the amplitude width of the magnetic field strength of process 37 is performed. Finally, a process for synthesizing the three templates is performed by the synthesis process 38. A template waveform can be created by the above processing.

  Next, a sub-processing flow for creating the PQ template 35 or QRS template 34 described in FIG. 3 is shown in FIG. 4, and a schematic diagram of the processing will be described with reference to FIG. However, the flow shown in FIG. 4 is processed independently for each PQ template and QRS template, but here, since the processing flow is the same, only one description will be given. When the process flow is started 41, a data length adjustment process 42 is performed. Since the time width of the waveform is different for each subject in the process 42, zero is set after each subject's data so that the longest data length of the QRS waveform or PQ waveform is obtained in all subjects (here, data of 464 people). To adjust the data length (see the schematic diagram of the data length adjustment processing 51 in FIG. 5). However, in this process 42, since it is known that the change in the PQ time and QRS time of the subject is small depending on the age and gender, the PQ waveform and the QRS waveform of each subject are not expanded in the time axis direction, and so on. Only the value of is extended and inserted. In the next amplitude normalization process 43, the magnetic field intensity of the cardiac magnetic field waveform changes due to the difference in the distance between the heart and the magnetic sensor in the cardiac magnetic field waveform, so the magnetic field measured in all channels after each subject. A process of setting the amplitude value having the largest magnetic field strength in the waveform to 1 is performed (see the schematic diagram of the amplitude normalization process 52 in FIG. 5). As described above, optimal processing is performed after knowing the characteristics of the PQ waveform and QRS waveform of the cardiac magnetic field waveform. Finally, in the averaging process 44, PQ templates and QRS templates can be created by adding and averaging the magnetic field waveforms of all subjects for each channel (see the schematic diagram of the averaging process 53 in FIG. 5). When the template is created by the averaging process 44, the main process 45 continues the process to the process 36 in FIG.

  Next, a sub-processing flow for creating the ST-T template 33 described in FIG. 3 is shown in FIG. 6, and a schematic diagram of the processing will be described with reference to FIG. When ST-T template creation start 61 is performed, first, the waveform from the end of the S wave (J point) to the end of the T wave (ST-T waveform) for each subject is centered on the top of the T wave. A waveform division process 62 is performed to divide the waveform into two parts, a Tpeak waveform and a Tpeak-Tend waveform (see the schematic diagram of the waveform division process 71 in FIG. 7). Next, a first waveform expansion process 63 (see a schematic diagram of the first waveform expansion process 72 in FIG. 7) is performed to expand the waveform so that the time width of the ST-Tpeak waveform of each subject becomes 1001 ms. Next, using the waveform expansion rate used in the first waveform expansion process 63, the Tpeak-Tend waveform of each subject is converted into a second waveform expansion process 64 (second waveform expansion process 73 in FIG. 7) in the time width direction. (See the schematic diagram). Next, a waveform synthesizing process 65 for synthesizing the waveform obtained by the first waveform enlarging process 63 and the waveform obtained by the second waveform enlarging process 64 into one waveform is performed. Next, a data extension process 66 is performed by inserting zeros so that the data lengths of all the subjects become the longest data length among the data lengths of all subjects obtained in the waveform synthesis process 65. Next, normalization processing 67 is performed so that the amplitude value of the magnetic field of each subject becomes 1. Finally, an averaging process 68 is performed on the waveforms for each channel using the data of all subjects. After the averaging process 68 is completed, the process returns to the main process 69, and the processes 36, 37, and 38 of FIG. 3 are performed to complete the template waveform.

  FIG. 8 shows a superimposed waveform of template waveforms obtained by performing the processing shown in FIGS. 3 to 7, and FIG. 9 shows a grid map waveform in which the waveforms are displayed in the arrangement of each channel. FIG. 8 shows a waveform 82 in which all 64 waveforms are overwritten on the trace 81. From these superimposed waveforms 82, P waves, QRS waves, and ST-T waves can be clearly confirmed. The grid map waveforms 91-1, 91-2,..., 91-64 in FIG. By creating a template waveform as described above, it is possible to easily understand an average cardiac magnetic field change.

  9 is divided into six regions shown in FIG. 10 from the shape (101 to 106) of the QRS waveform in the grid map display of the template waveform shown in FIG. Q1 waveform 101 appears in M1, QS waveform 102 appears in M2, qRs waveform 103 appears in M3, rSr ′ waveform 104 appears in M4, and rS waveform 105 appears in M5. , Ms is an Rs waveform 106. Each part from the heart contour 107 corresponds to the position of M1 in the right ventricle, M2 in the vicinity of the septum, M3 in the left ventricle (upper), M4 in the right ventricular lower wall, M5 in the apex, and M6 in the left ventricular side wall. This region dividing means has an advantage that it is easy to clearly specify a part where an abnormal waveform or an abnormal current arrow appears, and the findings can be efficiently described. FIG. 15 and FIG. 16 specifically summarize the effects of the area dividing means using the template waveform. It can be seen that typical waveform patterns and current patterns appear in each region (M1 to M6) as shown in FIGS. The six regions in this example are divided into three in the vertical direction with respect to the axis of the heart toward the apex and divided into two in the axial direction of the heart, so that the heart region is upper left, middle upper, upper right, lower left, middle It can be expressed simply as “bottom” or “bottom right”. These six area divisions are division methods obtained as a result of detailed examination of the characteristics of the average cardiac magnetic field using the template waveform as shown in the present embodiment, and are not easily found. However, in the present embodiment, the means for dividing into six regions has been described, but this is not limited to six, and a dividing method that can clearly understand the positional relationship with the heart region may be adopted.

In order to explain the characteristics of the current arrow obtained from the template waveform of FIG. 16 in an easy-to-understand manner, FIGS. 11 to 13 show changes in the current arrow at the time when each P, QRS, and ST-T waveform appears.
In FIG. 11, the change 11-2 of the current arrow at the P wave time 11-1 in the superimposed diagram shown in the upper part is shown in the lower part. From the current arrow change 11-2, right atrial excitement toward the lower right direction is recognized mainly in the region of M2.
In FIG. 12, the current arrow change 12-2 at the QRS wave time 12-1 in the superimposed diagram shown in the upper part is shown in the lower part. During the first Q wave (230-236ms), a current from the left ventricle to the right ventricle, mainly called the septal vector, is observed from M4 to M5. Next, the current excitation of the reverse L-shaped pattern centering on M2 and M5 is observed near the R wave peak. In the last S wave, a current in the upper left direction is recognized near the boundary region between M1 and M2.

  In FIG. 13, the current arrow change 13-2 at the T wave time 13-1 in the superimposed diagram shown in the upper part is shown in the lower part. It can be seen that the same current pattern occurs from the beginning to the end in the T wave. The main current appears in the M2 region as a current toward the lower right.

  The above has shown the method and effect of creating a template waveform and the method and effect of dividing into six regions.

  Next, means for creating a differential waveform using the template waveform shown in FIGS. 8 and 9 will be described with reference to FIGS. 17, 18, and 19. FIG.

  FIG. 17 shows a main processing flow. When the differential waveform generation is started, the waveform of the target for generating the differential waveform is the same as the waveform division processing 31 shown in FIG. A waveform division process 171 is performed on the target waveform) to divide the waveform into three parts: a P wave, a QRS wave, and an ST-T wave. A template is created with three parts of the PQ template 173, the QRS template 174, and the ST-T template 175 of the difference target waveform. (The creation of each template will be described with reference to FIGS. 18 and 19.) When the template waveform of the difference target waveform is completed, the comparison target process 176 is performed for each template. Processes 177 and 178 are performed so as to match the data length of the difference target waveform and the data length of the template waveform. However, the template waveform here refers to the PQ template 35, the QRS template 34, and the ST-T template 33 that have not been subjected to the processing 36 and subsequent steps in FIG. At the stage where the data length becomes the same, a difference process 179 is performed in which a template waveform is performed for each channel from the difference target waveform.

  FIG. 18 shows a method of creating a PQ template or QRS template of a difference target waveform. Since the PQ template and QRS template basically do not require processing such as normalization in the time axis method, only the normalization processing 182 that normalizes only the amplitude value of the magnetic field to 1 when the creation start 181 is performed. And return to the main process (183). However, if a conduction delay or the like occurs and the waveform enlargement process is necessary in the time axis direction, the waveform enlargement process may be inserted before or after the normalization process 182.

  FIG. 19 illustrates an ST-T template creation method for a difference target waveform (this is almost the same method as the ST-T template creation method in FIG. 6). When the start 61 is performed, first, the waveform from the end of the S wave to the end of the T wave (ST-T waveform) of the difference target waveform is centered on the top of the T wave, and an ST-Tpeak waveform and a Tpeak-Tend waveform. A waveform division process 192 is performed to divide it into two. Next, a first waveform expansion process 193 is performed to expand the waveform so that the time width of the ST-Tpeak waveform of the difference target waveform is 1001 ms. Next, a second waveform expansion process 194 is performed on the Tpeak-Tend waveform of each subject in the time width direction using the waveform expansion ratio used in the first waveform expansion process 193. Next, a waveform synthesizing process 195 is performed in which the waveform obtained in the first waveform enlarging process 193 and the waveform obtained in the second waveform enlarging process 194 are connected and synthesized into one waveform. Next, normalization processing 196 is performed so that the amplitude value of the largest magnetic field among all the channels of the difference target waveform is 1. After the normalization process 196 is performed, the process returns to the main process 197, and the processes 176 and 179 in FIG. 17 are performed to complete the differential waveform process.

  The difference between the healthy subject and the ischemic patient is shown in FIG. 20 to FIG.

  FIG. 20 shows a typical example of a healthy person in the difference process. It can be seen that the ST-T waveform is clearly visible in the waveform 201 before the difference, whereas the ST-T waveform is hardly visible in the waveform 202 after the difference. Further, when the current arrow diagram 203 is created from the ST-T waveform of the differential waveform, the value is small enough that almost no current is recognized.

  On the other hand, FIG. 21 shows a typical example of differential processing of a typical ischemic patient. Even in the waveform 211 before the difference, a slight ST change is recognized in the ST portion, but in the waveform 212 after the difference is performed, the ST change is more noticeable and the entire T wave remains clearly. Further, when the current arrow diagram 213 of the differential waveform is created, a current directed toward the lower left direction is clearly recognized in the vicinity of the M2 region.

図２２には健常者群と虚血患者群でのそれぞれの平均値と分散の値を図示したものである。最大磁場強度を比較した図２２１、最大電流強度を比較した図２２２、TCV強度を比較した図２２３のどれを見ても2群間で大きな違いが認められる。次に図２２の平均値に分散値（SD）1個分（１SD）あるいは2個分（２SD）を足したところを閾値として感度および特異度を求めたものが図２３である。図２３を見ると、１SDでおよそ７５％程度の高い感度と８５％程度の高い特異度が現れており、本実施例の手法の有効性が示されている。 FIGS. 22 and 23 show the same process as the typical example shown in FIGS. 20 and 21, and quantitatively summarize the data for 454 healthy persons and the data for 41 patients. FIG. 22 compares the maximum magnetic field intensity, the maximum current intensity, and the total current vector amount (TCV) after the difference processing. TCV (I) is a value calculated as follows from the current vector (I _n ) at each measurement point.

FIG. 22 shows the average value and the variance value in the healthy subject group and the ischemic patient group. There is a large difference between the two groups in any one of FIG. 221 comparing the maximum magnetic field strength, FIG. 222 comparing the maximum current strength, and FIG. 223 comparing the TCV strength. Next, FIG. 23 shows the sensitivity and specificity obtained with the threshold value obtained by adding one variance value (SD) (1SD) or two variance values (2SD) to the average value in FIG. As shown in FIG. 23, high sensitivity of about 75% and high specificity of about 85% appear in 1SD, which shows the effectiveness of the method of this example.

  As described above, the waveform and the current arrow diagram obtained by the differential processing with the ST-T waveform are considered to be effective for determining the presence and degree of ischemia. Also, PQ waveforms and QRS waveforms can be visualized for abnormal excitement such as arrhythmia, conduction disorder, and ischemic heart disease by performing the same processing as ST-T waveform.

The figure which shows the apparatus structural example of the Example of this invention. The figure which shows the sensor arrangement example of the Example of this invention. The figure which shows the main flow of template waveform creation which is a 1st Example of this invention. The figure which shows the creation subflow of the PQ template and QRS template which are the 1st Examples of this invention. The figure which shows the schematic diagram of the creation flow of the PQ template and QRS template which are shown in FIG. The figure which shows the creation subflow of the ST-T template which is the 1st Example of this invention. The figure which shows the schematic diagram of the creation flow of the ST-T template shown in FIG. The figure which shows the template waveform of the cardiac magnetic field produced using the process of FIGS. 3-7 which is a 1st Example of this invention. This drawing shows a waveform in which 64 template waveforms are overwritten on one trace. The figure which shows the template waveform of the cardiac magnetic field produced using the process of FIGS. 3-7 which is a 1st Example of this invention. In this drawing, a template waveform is displayed in the arrangement of each sensor. The figure which is the 2nd Example of this invention, and shows the shape of the QRS waveform typically corresponding to six division areas and each area | region. A divided region is determined from the characteristics of the cardiac magnetic field waveform. The figure which shows the time change of the current arrow figure (P wave) obtained from the template waveform shown in the 1st and 2nd Example of this invention, and the figure which shows the Example which displays six division areas simultaneously. The figure which shows the time change of the current arrow figure (QRS wave) obtained from the template waveform shown in the 1st and 2nd Example of this invention, and the figure which shows the Example which displays six division areas simultaneously. The figure which shows the time change of the current arrow figure (T wave) obtained from the template waveform shown in the 1st and 2nd Example of this invention, and the figure which shows the Example which displays six division areas simultaneously. The figure which represented the numerical value of the average magnetic field strength and time width used for the template waveform preparation means of 1st Example of this invention. The figure which put together the waveform characteristic of the template waveform produced in the 1st Example in the six division area of the 2nd Example of this invention. The figure which put together the characteristic of the current arrow figure of the template waveform produced in the 1st example in six division fields of the 2nd example of the present invention. The figure which shows the main flow which produces the difference waveform which is the 3rd Example of this invention. The figure which shows the subflow of the PQ template and QRS template which produce the difference waveform which is the 3rd Example of this invention. The figure which shows the subflow of the ST-T template which produces the difference waveform which is the 3rd Example of this invention. The figure which shows the waveform before and behind the difference of the healthy subject created by the difference waveform process which is the 3rd Example of this invention, and the figure which shows the time change of the current arrow figure obtained from the waveform after a difference. The figure which shows the waveform before and behind the difference of the ischemic heart disease patient created by the difference waveform process which is the 3rd Example of this invention, and the figure which shows the time change of the current arrow figure obtained from the waveform after a difference. The figure which compared the maximum magnetic field intensity | strength, the maximum electric current intensity | strength, and the TCV intensity | strength in a healthy subject group and an ischemic heart disease group from the difference waveform produced by the difference waveform process which is the 3rd Example of this invention. When the healthy group (454 people) and the ischemic heart disease group (41 people) of FIG. 22 created by the differential waveform processing according to the third embodiment of the present invention are used as the threshold value (average value + 1SD) The figure which shows the result of having calculated sensitivity and specificity in the case where (average value + 2SD) is used as a threshold value. SD is the standard deviation.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Magnetic shield room, 2 ... Cryostat, 3 ... Gantry, 4 ... Drive circuit, 5 ... Amplifier filter unit, 6 ... Computer, 7 ... Bed, Detection coil 8-1 to 8-64 ... Detection coil, 30 ... Template Start, 31 ... waveform division, 32 ... template creation means for each waveform, 33 ... ST-T template, 34 ... QRS template, 35 ... PQ template, 36 ... time width adjustment processing means, 37 ... amplitude width of magnetic field strength Adjustment processing means, 38 ... synthesis processing means, 41 ... template creation start means, 42, 51 ... data length extension means, 43, 52 ... means for normalizing the amplitude value of the magnetic field strength, 44, 53 ... addition of all subject data Average processing, 45 ... means for returning to the main processing, 61 ... ST waveform template creation start means, 62, 71 ... waveform dividing means, 63, 72 ... ST-Tp Waveform enlarging means in the time axis direction for setting the data length of the eak waveform to 1001 ms, 64, 73... Waveform enlarging means in the time axis direction for the Tpeak-Tend waveform (magnification rate uses the value used in the means 63), 65 ... ST-Tpeak waveform and Tpeak-Tend waveform synthesizing means, 66 ... means for extending the data length, 67 ... means for normalizing the amplitude value of the magnetic field to be 1, 68 ... means for adding and averaging the waveforms 69 ... Means for returning to the main processing, 81 ... Trace, 82 ... Waveform superposition diagram of cardiac magnetic field template waveforms created by the method of Figs. 3 to 7, 91-1, 91-2, ~ 91-64 ... each Drawing of cardiac magnetic field template waveform at sensor position, 101 ... M1 region, 102 ... M2 region, 103 ... M3 region, 104 ... M4 region, 105 ... M5 region, 106 ... M6 region, 107 ... heart outline, 11- 1… When drawing a P-wave current arrow diagram A window showing a band, 11-2 ... a diagram showing a time change of a current arrow diagram at a P wave time, 11-3 ... a diagram showing six regions, 12-1 ... a time zone for drawing a current arrow diagram of a QRS wave Window, 12-2... Time variation of current arrow diagram at QRS time, 12-3... Six regions, 13-1 Window of T wave current arrow drawing time zone, 13 -2 ... Diagram showing time variation of current arrow diagram at T wave time, 13-3 ... Diagram showing six regions, 171 ... Waveform dividing means for difference target waveform, 172 ... Template creation of each waveform of difference target waveform Means 173: PQ template creation means for the difference target waveform, 174 ... QRS template creation means for the difference target waveform, 175 ... ST-T template creation means for the difference target waveform, 176 ... Data length and template of the difference target waveform Means for comparing the data lengths of the first waveform, 177... Means for adjusting the data length of the difference target waveform by adding zero to the data length of the template waveform. 178..., Adding the data length of the template waveform by adding zero. , 181... Difference processing means, 181... PQ template or QRS template waveform generation start means for the difference target waveform, 182... Normalization means for setting the amplitude value of the difference target waveform to 1, 183. 191 ... ST-T waveform template creation start means for the difference target waveform, 192 ... ST-T waveform splitting means for the difference target waveform, 193 ... ST-Tpeak waveform time width of the difference target waveform to be 1001 ms Waveform enlarging means for enlarging the waveform in the time axis direction, 194... Enlarging the time width of the Tpeak-Tend waveform of the difference target waveform for each subject obtained by the processing 193 Magnifying means for performing waveform magnifying processing in the time axis direction using the values of 195..., Waveform synthesizing means for two template waveforms, 196... Normalizing means for normalizing the amplitude value of the difference target waveform to 1, 197. Means for returning to main processing, 201 ... ST-T waveform before difference in healthy person, 202 ... ST-T waveform after difference in healthy person, 203 ... Current arrow diagram at time of ST-T waveform after difference in healthy person FIG. 204 is a diagram showing temporal changes of 204, 204 is a diagram showing six regions, 211 is an ST-T waveform before the difference in the ischemic patient, 212 is an ST-T waveform after the difference in the ischemic patient, 213 is in the ischemic patient The figure which shows the time change of the current arrow figure in the time of the ST-T waveform after a difference, 214 ... The figure which shows six area | regions, 221 ... The figure which compared the maximum magnetic field intensity, 222 ... The figure which compared the maximum current intensity ... TCV intensity comparison .

Claims (2)

Magnetic field detection means for detecting a cardiac magnetic field generated from the subject's heart ;
Time division means for dividing a cardiac magnetic field detection waveform of a plurality of subjects obtained by the magnetic field detection means into a plurality of components, respectively, according to waveform progress ;
A plurality of partial template creation means for creating a template of each component based on the cardiac magnetic field detection waveform of the plurality of subjects by performing addition averaging processing of the data of the detection waveforms of the plurality of subjects for each component ;
In the biomagnetic field measurement apparatus having a waveform synthesizing unit that synthesizes the created template of each component and creates a template waveform of the cardiac magnetic field based on the cardiac magnetic field detection waveform of the plurality of subjects ,
The ST-T template creation means for creating the template of the ST-T component including the T wave among the partial template creation means of the subject includes the waveform divided into the ST-T components of each subject, Waveform division processing means for dividing the waveform into two waveforms in the time zone before and after the time point with the largest amplitude of the waveform, and waveform expansion for expanding the time scale of the front waveform obtained by the waveform division processing before and after to a constant value First enlargement processing means for performing processing, and second enlargement processing means for performing waveform enlargement processing on the rear side waveform obtained by the front and rear waveform division processing using the enlargement ratio used by the first enlargement processing means. And a connection processing means for connecting the front waveform and the rear waveform after the waveform enlargement processing, and an averaging process is performed from the waveform of each connected subject to obtain an ST-T component template A biomagnetic field measurement apparatus having waveform addition averaging processing means . The ST-T template creation means is configured such that the longest data length of the waveforms divided into the ST-T components of each subject is zero so that the data length of the waveforms connected to all the subjects is the same. Is further provided with means for performing a data extension process for adding the data and a normalization process for normalizing the connected waveform of each subject so that the amplitude value of each subject is 1. The biomagnetic field measurement apparatus according to claim 1, wherein a waveform of each subject that has undergone the normalization process and the waveform of each subject is collected in the arithmetic mean processing means to obtain a template of the ST-T component .

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