JP3504122B2 - Biomagnetic field measurement system - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a biomagnetism measuring system for measuring a weak magnetic signal generated by a subject in a magnetically shielded room, and more particularly to displaying diagnostic data.

[0002]

2. Description of the Related Art Recently, a plurality of superconducting quantum interference devices (SQ
A biomagnetism measurement system has been devised, in which a weak magnetic field generated from a human body is detected using a magnetic sensor composed of a UID) and a diagnosis is made by observing a time change of the detected magnetic signal.

The biomagnetism measuring system is provided with a detecting section in which a plurality of magnetic sensors are arranged at appropriate intervals, and the detecting section is brought close to a portion of the body of the subject to be measured to obtain a magnetic signal. A channel number is set for each magnetic sensor, and changes in the magnetic signals of various parts of the human body can be read based on the output of this channel number. It may be used for diagnosis.

In the above biomagnetic field measurement system, in order to analyze the measured magnetic field data, the measured magnetic field data is reconfigured into a format such as an isomagnetic field diagram or a time waveform, and is monitored as diagnostic data. Is displayed.

In this case, at present, only magnetic field data obtained by one measurement can be reconstructed and displayed as diagnostic data.

[0006]

Therefore, for example, when the diagnostic data are reconstructed from different magnetic field data, for example, the progress of a certain subject before and after surgery is observed, and the diagnostic data are displayed simultaneously for comparison, It is necessary to define and enter the various conditions (parameters) that should be reconstructed for magnetic field data for each magnetic field data.
There is room for improvement in operability such as it takes time to actually display it.

Further, since many parameters are designated for each magnetic field data in order to obtain diagnostic data, there is a problem that the reproducibility of data is poor.

An object of the present invention is to provide a biomagnetic measurement system that efficiently compares arbitrary display forms reconstructed from a plurality of magnetic field data and efficiently reproduces the reconstructed data once.

[0009]

A feature of the present invention for achieving the above object is to detect the magnetism generated by a living body at an arbitrary time interval by a plurality of magnetic sensors arranged at a predetermined interval. In a biomagnetic measurement system having a display means for displaying a magnetic signal detected by a magnetic sensor in an arbitrary display form, a data storage means for storing each of a plurality of magnetic signals possessed by a plurality of subjects as measurement data, A selection means for selecting any measurement data from the data storage means and a designation means for designating a display form of the measurement data selected by the selection means are provided, and all the selected measurement data are designated by the designation means. Displaying on the display means based on the designated display form.

In the present invention, by simultaneously displaying an arbitrary display form created from a plurality of magnetic field data, a plurality of data can be easily compared, and an arbitrary display form can be created from magnetic field data. Therefore, since the number of parameters to be input can be reduced, an efficient diagnosis method and reproduction method that do not depend on the memory of the operator can be realized.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION First, a biomagnetism measuring system to which the present invention is applied, particularly a system for measuring the magnetism of the heart will be described.

FIG. 1 shows an outline of the system.

The biomagnetism measurement system measures by detecting the weak magnetism generated by the human body.
Since the magnetism emitted from the human body is very weak, it is performed inside the magnetically shielded room 1 in order to eliminate the influence of environmental magnetic noise. Then, in order to detect the weak magnetism, a plurality of magnetic sensors including superconducting quantum interference devices (SQUIDs) are used.

When the subject 2 is measured, it is laid on the bed 3 and measured (as shown in FIG. 4, the orthogonal coordinate system (x, y, z) so that the xy plane becomes the bed plane). Set).

A dewar 4 functioning as a detection unit is arranged above the chest of the subject 2. In the dewar 4, the SQUID 23 and the detection coil 21 connected to the SQUID 23 as shown in FIG.
A plurality of magnetic sensors integrated with and are housed and further filled with liquid helium. Liquid helium is continuously replenished with liquid helium by an automatic replenishing device 5 outside the magnetic shield room 1.

The output from the magnetic sensor is a FLL (Flux) which outputs a voltage proportional to the magnetic field strength detected by the detection coil.
Locked Loop) circuit 6 is input. This FLL circuit 6
Cancels the change in biomagnetism input to the SQUID via the feedback coil so as to keep the output of the SQUID constant. By converting the current flowing through the feedback coil into a voltage, a voltage output proportional to the change in the biomagnetic signal can be obtained. This voltage output is amplified by an amplifier (not shown), the frequency band is selected by the filter circuit 7, AD-converted by an AD converter (not shown), and the computer 8
Is taken into. In the computer 8, various kinds of arithmetic processing are executed, the arithmetic processing result is displayed on the display, and further output to the printer 9.

The layout of the magnetic sensor in the dewar 4 is shown in FIG.
Shown in. The magnetic sensors were installed vertically from the bottom inside the dewar, and the distance between the sensors was set at equal intervals in the x direction and the y direction so as to accurately capture the amount of change in the magnetic distance. Here, the distance between the sensors is 25 mm, and the number of sensors is 8 x
There are 8 64 channels.

Each of the magnetic sensors is a sensor for measuring a component Bz perpendicular to the body surface, and is a superconducting wire (Nb-T).
The surface of the coil created by (i line) faces the z direction. This coil is a combination of two coils in opposite directions. One closer to the living body is used as the detection coil 21, and the farther coil is used as the reference coil 21 for removing external magnetic field noise, forming a temporary differential coil. Here, the coil diameter is 20mmΦ,
The distance baseline between the coils was 50 mm. External magnetic field noise originates from a signal source farther than the living body, and these are similarly detected by the detection coil 21 and the reference coil 22. On the other hand, since the signal from the human body is close to the coil, it is detected more strongly by the detection coil 21. Therefore, the detection coil 21
In, the signal and noise are detected, and in the reference coil 22, only noise is detected. Therefore, a high S / N can be measured by taking the difference between the magnetisms captured by both coils. The temporary differential coil is connected to the input coil of the SQUID23 via the superconducting wiring of the mounting board on which the SQUID23 is mounted, and transfers the biomagnetic component detected by the coil to the SQUID23.

The dewar 4 having a built-in magnetic sensor is arranged above the chest of the subject 2 lying on the bed 3 and measures the cardiac magnetism (hereinafter, magnetocardiography) generated from the heart. here,
The lateral direction of the body is the x-axis, and the vertical direction of the body is the y-axis. The positional relationship between the arrangement of the magnetic sensors (30-1 to 8, ..., 37-1 to 37-8) and the chest 30 is shown in FIG. Also, FIG.
The waveforms shown in the lower part of FIG. 3 are time waveforms detected by the magnetic sensors.

Next, examples of the present invention will be described.

FIG. 5 is a screen for selecting a subject and its data. The upper half area of FIG. 5 is a subject list 503, which displays a list of a plurality of subjects. The lower half area is a data list 510 for displaying a list of data held by each subject.

The gray cursor 504 displayed in each list indicates that the subject or data for which the cursor is currently displayed is selected. In FIG. 5, John Baker is selected as the subject, and the data list 51 is selected.
At 0, a list of John Baker's data is displayed.

In the data list 510 item display,
“Data type” indicates the type of data, and “MC
There are two types, G ”and“ ANA. ”“ MCG ”indicates magnetic field data and“ ANA ”indicates reconstruction condition data.

Here, the magnetic field data refers to the magnetic data measured by each magnetic sensor shown in FIG. 3 in consideration of the arrangement state of each magnetic sensor shown in FIG. 4, and is so-called measurement data. . The relationship between the arrangement of the sensors and the respective magnetic data is as shown in FIG.
The magnetic data of (31) corresponds to the sensor of No. 3, and the magnetic data of (32) corresponds to the sensor of 37-8.

Further, the reconstruction condition data indicates information necessary for displaying the magnetic field data on the monitor, so-called parameters. FIG. 11 shows the reconstruction condition data. This data is normally stored in a storage device such as a hard disk of the system, and from the contents displayed in the subject list 503 and the data list 510, various parameters described later and the same screen are displayed. It has various kinds of management information for forming a display screen, such as the number of MCG data to be processed.

An embodiment for reconstructing diagnostic data from magnetic field data according to the present invention will be described below with reference to the flow chart shown in FIG.

In this embodiment, the subject John Baker shown in FIG.
The magnetic field data before and after surgery should be compared.

First, as shown in FIG. 6, the subject list 5
Select the column of John Baker from 03, data list 510
Display John Baker's data on. Then, the data to be displayed is selected from the data list 510 (110).
1). Here, if the selected data is reconstruction data, that is, "ANA", then the analysis menu 502
When "reproduction" is selected from, the reconstruction condition data previously defined in the state as shown in FIG. 11 is read (1103),
The process moves to the next step (1104), and the display is performed on the monitor.

The selected data is magnetic field data, that is, "M
If it is "CG", the reconstruction condition is not set yet, so first, the analysis menu (50
The mapping type is selected from 2) to be one of the reconstruction conditions, and the other reconstruction conditions are set for the time being using default values (1102).

Then, the selected data is displayed using the reconstruction condition (1105) (1106).
Here, when there are a plurality of selected magnetic field data, it is determined whether or not all the data is displayed in step (1107). If there is data that is not yet displayed, the process returns to step (1104) and all the data is displayed. Is repeated until is displayed. In this embodiment, the magnetic field data are No. 1 and N.
Since two of o.2 are selected, (1104) to (1
Step 107) is repeated twice. Further, since "equal magnetic field diagram" is selected as the type of mapping, the screen up to which the isomagnetic field diagram is reconstructed as shown in FIG. 7 is displayed by the processing up to this point. FIG. 7 shows magnetic field data No. 1 and N.
Equal magnetic field diagrams 618 and 619 respectively corresponding to No. 2 are displayed, and the subject ID and the data No. are displayed in each diagram.

When the screen transitions to the screen of FIG. 7, it is possible to set various parameters of the reset condition or save the reconstruction condition at this time in this state (1108).

Here, the setting of reconstruction conditions will be described. In the screen of FIG. 7, the waveform boxes (602, 603, 604), mapping boxes (605, 606, 607), component boxes (608, 609), and arrow map boxes are used as the reconstruction conditions. (61
0), parameter boxes (611, 612, 613),
And a time selection indicator (616).

Although not shown in this embodiment, the "waveform" is a kind of magnetic field data drawing method, in which the vertical axis represents the intensity of the measured signal (unit: Tesla) and the horizontal axis represents the time when the signal was measured. The measured signals are graphically displayed in time series. A monitor waveform 614 described later is one form of this waveform display.

When the single waveform button 602 is selected, only one of a plurality of magnetic data for each magnetic sensor in one magnetic field data is displayed as a waveform. At that time, the designation of the magnetic sensor is made in the channel selection box 6
It starts from 01.

By using the grid map button 603, the data of all the channels in the magnetic field data are collectively displayed. The display form is a waveform display according to the sensor arrangement as shown in the lower part of FIG.

With the overlay button 604, the waveforms of a plurality of magnetic sensors are overlaid on the above single waveform display form.

"Mapping" is a button for selecting the isomagnetic field diagram, the propagation time distribution or the time integration as a display form of the magnetic field data. In the embodiment, the isomagnetic field diagram is selected in the analysis menu. The line drawing button 605 is selected.

Here, the contour magnetic field diagram is a diagram in which the magnetic field strength of the signal measured at a certain time is displayed as contour lines.

The propagation time distribution diagram is a diagram in which the propagation time from a certain reference time calculated for each magnetic sensor to the time when the value of the measurement signal becomes maximum is displayed as contour lines.
Generally, the movement of the heart produces an electric current in the heart, which moves in the heart. And when the current is closest to the sensor, that sensor observes the maximum magnetic field strength. Therefore, the movement of the current can be observed by obtaining the propagation time for each magnetic sensor.

The time integral diagram is a diagnostic means for diagnosing the heart for diseases such as ischemia. Specifically, it is a diagram in which the amount obtained by adding the magnetic field data between arbitrary two times among the measured signals is displayed as contour lines. Generally, with the activity of the myocardium, an electric current flows in the heart, thereby generating a strong magnetic field. The time-integral diagram is a diagnostic means based on the fact that if there is a disease in the heart, the movement of the myocardium becomes slow and the current flowing becomes weak. If this diagnostic means is used, the data obtained by subtracting the time integral value during the diastole of the heart and the time integral value during the systole of the heart are displayed as contour lines, and the movement of the myocardium during diastole and systole is displayed. You can see the difference between.

The "component" is a button for selecting the component (normal or tangential direction) of the magnetic field to be reconstructed. The component of the selected magnetic field is displayed as an isomagnetic field map.

The "arrow map" is a check box for selecting whether or not to display the direction and magnitude of the measured current with an arrow. The arrow map display shows the two components (X,
Y) can be obtained. (However, it is not displayed in this embodiment.) “Parameter” is a map number designation box 611 for designating the number of maps to be displayed on the screen, and a maximum magnetic field designation for designating the maximum magnetic field of the scale 617 showing the magnetic field strength of the diagnostic data. A box 612 and a magnetic field interval designation box 613 for designating the interval between contour lines of the contour plot.

The map number designation box 611 indicates the number of maps to be loaded in each data. That is, when performing measurement, a plurality of magnetic field data are taken in at arbitrary sampling intervals, and a plurality of magnetic field data can be displayed corresponding to the sampling time for each data. The numerical value input in the map number designation box 611 designates how many maps are to be displayed from a plurality of magnetic field data.

The maximum magnetic field designation box 612 is for defining the maximum magnetic field of the scale 617. The scale 617 is a scale that represents the numerical magnetic field input in the maximum magnetic field designation box 612 as the maximum magnetic field,
This is an index for viewing the strength of the magnetic field of the mapped and displayed angular magnetic field data. That is, in this embodiment, since 200 pT is input, the scale 617
Is a scale display from +200 pT to -200 pT.

Here, the scale 617 displays the one representing the maximum magnetic field as "red", the one representing the minimum magnetic field as "blue", and the middle zero position as "yellow", and changes the color tone between them. , Is displayed so that it changes gradually. And
In the contour lines 618 and 619, the color indicating the corresponding magnetic strength is displayed on the scale 617 according to the magnetic strength.

The magnetic field interval designation box 613 is for adjusting the interval of the contour lines of the contour magnetic field diagram. When the numerical value here is increased, the interval of the contour lines is displayed broadly, and conversely when the numerical value is decreased, the contour line displayed is decreased. The intervals are close.

The "time selection indicator" 616 is a cursor indicating the temporal position of the magnetic field data currently displayed.

The monitor waveform 614 displayed below the area where the time selection indicator 616 moves displays the time waveform of the data measured by one of the magnetic sensors of the magnetic field data initially selected in step (1101). Then
This is an area showing the time index of the diagnostic data in the magnetic field data. The monitor waveform selector button 615 is an area for designating the channel of the magnetic sensor.

The cursor 621 displayed on the monitor waveform 614 is a mapped diagram (that is, isomagnetic field diagrams 618 and 619 displayed as diagnostic data).
Indicates the displayed time, and the number is linked with the number designated in the map number designation box 611.
In the example of FIG. 6, since the number of maps is set to “3”,
Three cursors 621 are also displayed.

The update time interval of the displayed data is the interval indicated by the cursor 621. When one of the cursors 621 is clicked and moved, the time interval can be changed.

Further, when the time selection indicator 616 is clicked with the mouse cursor 620 and moved to any position of the cursor 621, the data corresponding to that time is displayed.
8, 619.

The above are the parameters that can be set as reconstruction conditions. You can reset the above parameters at any time, but if you want to do so, go to step (11
The process returns from 08) to step (1102) to set the parameters and display the reconstruction based on the parameters input again. This allows the diagnostic data to be calculated repeatedly until the desired result is obtained by the user.

When the reconstruction conditions of the currently displayed state are to be saved, if either "New" or "Overwrite" is selected from the file menu 901 as shown in FIG. 10, the current reconstruction conditions are selected. Reconstruction condition data "AN
A "is recorded in the form as shown in FIG. 11 (11
09). Normally, when the screen is displayed by selecting "MCG" data, perform "New" and
If the screen is displayed from "ANA" data,
"Overwrite" will be performed.

After the magnetic field data is mapped and displayed as diagnostic data, marker display or distance measurement can be selected from the edit menu 702.

In the marker display processing (1110), as shown in FIG. 8, for example, with respect to one of the plurality of maps displayed on the monitor, an arbitrary point on the map 618 is clicked with the mouse cursor 620. Then, another map 61
For 9 as well, a marker 701 is displayed at the same coordinate. Further, when the mouse cursor 620 is clicked and moved on the screen, the markers on other maps can be moved in conjunction with the movement. This makes it possible to easily compare a plurality of diagnostic data at the same position. In particular, when it is applied to the display of the same patient before and after the operation as in the present embodiment, it becomes possible to accurately observe how the previous diseased part has changed.

In the distance measurement processing (1112), as shown in FIG. 9, when any two points on a certain map are designated by the mouse cursor 620, a line is drawn between the two points and the distance between the two points is drawn. (Unit is millimeter) is displayed on the monitor. Also in this process, a line is drawn between two points having the same coordinates on another map. According to this processing, similar to the above-mentioned marker display processing, it is possible to easily compare the same position of a plurality of diagnostic data, and especially when applied to the display of diagnostic data before / after surgery of the same patient. It is possible to quantitatively observe how the size of the diseased part before surgery has changed.

After the display as the diagnostic data is completed, unless the processing of the entire system is completed, the step (110
Returning to 2) again, the same processing is repeated (111
3). The steps from (1102) to (1110) are skipped and the process proceeds to the next step in sequence unless the process is required.

[0058]

According to the present invention, since a plurality of magnetic field data can be displayed simultaneously under the same reconstruction condition, quantitative diagnosis can be performed without depending on the memory of the operator.

Further, since a plurality of data can be diagnosed at once, it is not necessary to repeat the same processing for the number of data to be diagnosed as in the conventional case, and a mass examination for which a large amount of data needs to be diagnosed can be performed in a short time. Can be implemented.

Furthermore, since the reconstructing condition is stored and the diagnostic data can be reproduced based on the reconstructing condition, it can be easily confirmed again after the diagnosis, so that the erroneous diagnosis can be reduced.

[Brief description of drawings]

FIG. 1 is a diagram showing a schematic configuration of a biomagnetism measuring device for performing magnetocardiography.

FIG. 2 is a diagram showing a configuration of a magnetic sensor alone.

FIG. 3 is a diagram showing an arrangement configuration of magnetic sensors.

FIG. 4 is a diagram showing the arrangement of magnetic sensors and the positional relationship between the chest of the human body and the measured magnetic data.

FIG. 5 is a diagram showing a screen showing a subject list and a data list of the present invention.

FIG. 6 is a diagram for selecting data to be reconstructed and displayed.

FIG. 7 is an overall screen configuration diagram of the present invention.

FIG. 8 is a diagram showing a marker display function of the present invention.

FIG. 9 is a diagram showing a distance measuring function of the present invention.

FIG. 10 is a diagram showing a state during data storage of the present invention.

FIG. 11 is a diagram showing a structure of reconstruction condition data.

FIG. 12 is a processing flow chart of the present invention.

[Explanation of symbols]

1 ... Magnetically shielded room, 2 ... Subject, 3 ... Bed, 4
... Dewar, 5 ... Automatic replenishing device, 6 ... FLL circuit, 7 ... Filter circuit, 8 ... Calculator, 9 ... Printer, 21 ... Detection coil, 22 ... Reference coil, 23 ... SQUID, 20-1
~ 8,27-1 to 27-8,30-1 to 8,31-1 to
37-1, 31-8 to 37-8 ... Magnetic sensor, 30 ... Chest of subject, 31, 32, 33, 34 ... Data measured by magnetic sensor, 500 ... Monitor, 501 ... Title bar,
502 ... Analysis menu, 503 ... Subject list, 504
... Cursor, 505 ... Menu bar, 506 ... Subject list title, 507, 509, 511, 513 ... Scroll bar, 508 ... Data list title, 510 ...
Data list 512 ... Subject information 601, Channel selection box, 602 ... Single waveform button, 603 ... Grid map button, 604 ... Overlay button, 60
5 ... Equal magnetic field diagram button, 606 ... Propagation time button, 60
7 ... Time integration button, 608 ... Normal button, 609 ... Tangent button, 610 ... Arrow map button, 611 ... Map number designation box, 612 ... Maximum magnetic field designation box, 6
13 ... Magnetic field interval designation box, 614 ... Monitor waveform, 6
15 ... Monitor waveform selector button, 616 ... Time selection indicator, 617 ... Scale, 618, 619 ... Isomagnetic field diagram, 620 ... Mouse cursor, 621 ... Cursor, 701 ... Marker, 702 ... Edit menu, 80
1, 802 ... Solid line, 803, 901 ... File menu.

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Kenji Teshigawara, Inventor Kenji Teshigawara 882 Ichige, Hitachinaka City, Ibaraki Prefecture Hitachi Co., Ltd.Inside the Measuring Instruments Division (72) Keiji Tsukada 1-280, Higashi Koikeku, Kokubunji, Tokyo Hitachi, Ltd. Central Research Laboratory (72) Inventor Akihiko Kamtori 1-280, Higashi Koigokubo, Kokubunji, Tokyo Hitachi, Ltd. Central Research Laboratory (56) Reference JP 5-197767 (JP, A) JP 63-168152 (JP, A) JP 59-183461 (JP, A) JP 6-176079 (JP, A) JP 7-23944 (JP, A) JP 11-4814 (JP, A) Kohei 7-104401 (JP, B2) Japanese Patent Kohei 6-87075 (JP, B2) (58) Fields investigated (Int.Cl. ⁷ , DB name) A61B 5 / 05,8 / 00

Claims (5)

(57) [Claims] 1. A plurality of magnetic sensors arranged at a predetermined interval, data storage means for storing measurement data based on detection results of the plurality of magnetic sensors, and displaying the measurement data in an arbitrary display form. In the biomagnetism measurement system having: a display unit for selecting, a plurality of measurement data selecting units for selecting a plurality of measurement data to be displayed on the display unit from the measurement data stored in the data storing unit; A display form designating unit for designating a display form of data, including a contour line display form represented by adding position elements to measurement data in the display form which can be designated by the display form designating unit,
And an instruction display means for indicating or / and displaying one part of the display area of one measurement data displayed in the contour display form on the display means, and another measurement displayed on the display means in the contour display form. The data display area is provided with marker means for displaying a marker for comparison with the indicated point, and a plurality of measurement data designated by the display form designating means is further provided .
For each of the, time selection means to select the measurement time
A biomagnetic field measurement system characterized by being provided . 2. The biomagnetic field measurement system according to claim 1.
And the time selecting means measures with any of the magnetic sensors.
The cursor displayed on the time waveform of the recorded data
To select the time corresponding to the position of the cursor
A biomagnetic field measurement system characterized by the above. 3. The biomagnetic field measuring system according to claim 1, wherein the display means indicates one point in a display area of one measurement data displayed in the contour display form, and the display. A biomagnetic field measuring system comprising: a marker means for displaying a marker on the same coordinate as the designated one point in a display area of another measurement data displayed in the contour display mode on the means. 4. The biomagnetic field measuring system according to claim 1 or 2, further comprising: an instruction display unit for instructing two points in a display area of one measurement data displayed in the contour display form on the display unit; A line segment unit for displaying a line segment between two points on the same coordinates as the designated two points is provided in the display area of the other measurement data displayed in the contour line display mode on the unit. Biomagnetic field measurement system. 5. The biomagnetic measurement system according to claim 1 or 2, wherein information on a plurality of measurement data selected by the measurement data selecting means and / or a display form specified by the display form specifying means. Reproduction data storage means for storing information and reproduction data selection means for selecting the stored reproduction data are provided, and measurement data is displayed on the display means based on the selected reproduction data. Biomagnetic measurement system.