JP2021151429A - Biomagnetism measuring device and biomagnetism measuring system - Google Patents

Abstract

To estimate electric current distribution from biomagnetism data by specifying positional relationships between the position of a nerve and a magnetic sensor in magnetic field measurement using an ultrasonic image.SOLUTION: A biomagnetism measuring device includes: a sensor storage part for storing a magnetic sensor; a transparent plate member disposed separably on an opposed surface opposed to a detection part of the magnetic sensor in the sensor storage part; and an electric current estimation part for estimating electric current distribution in a measurement object part from biomagnetism data on the measurement object part measured by the magnetic sensor on the basis of positional relationships between the position of a nerve and the magnetic sensor obtained from position information on the nerve of the measurement object part that can be obtained by an ultrasonic probe brought into contact with the plate member with which the measurement object part comes in contact in a state that the plate member is separated from the opposed surface, and an image including the ultrasonic probe and the plate member at the time when the position information on the nerve is obtained.SELECTED DRAWING: Figure 1

Description

The present invention relates to a biomagnetic measuring device and a biomagnetic measuring system.

As a method for examining the functions of the spinal cord, peripheral nerves, muscles, etc., a method of measuring a magnetic field generated from a living body based on their activities is known. For example, in a biomagnetic measuring device that measures a magnetic field generated from the neck or the waist, the tip of each sensor in the sensor array is arranged along the curved shape of the measuring portion. Then, by taking an X-ray image from the side surface of the subject, the positional relationship between the sensor array and the nerve is acquired (see Patent Document 1).

Further, in another biomagnetic measuring device, the ultrasonic probe of the ultrasonic diagnostic device is arranged in the shield room in which the biomagnetic measuring device is arranged. Then, a sensor array that measures the magnetic field generated from the heart using the ultrasonic tomographic image of the heart is arranged at an appropriate measurement position of the subject, and the biomagnetic field is measured (see Patent Document 2).

In the biomagnetic measurement device, the radiation detection unit can be placed between the support unit and the biomagnetic measurement unit by making it possible to change the relative position between the detection target part of the subject supported by the support unit and the biomagnetic measurement unit. Can be placed. As a result, the position information of the detection target site can be acquired by the radiation detection unit in the same posture as the posture of the subject when measuring the biomagnetic field (see Patent Document 3).

By putting the lower leg in a synthetic resin boots-shaped water tank filled with hot water and applying an ultrasonic probe to the outer wall of the water tank, it is possible to obtain a cross-sectional image of the lower leg by suppressing the change in the shape of the lower leg due to the pressing of the ultrasonic probe. become. For example, the ultrasonic probe is applied to the outer wall of the aquarium corresponding to the position marked directly on the body surface of the subject (see Non-Patent Document 1).

In a biomagnetic measurement system such as a spinometer system, the nerve function is evaluated by estimating the current distribution in the body from the magnetic field data obtained by the sensor array by an estimation method such as a spatial filter method. Since the magnetic field data signal changes rapidly depending on the distance between the magnetic field source and the sensor, it is necessary to acquire the nerve position information in advance and give the acquired position information to an estimation method such as the spatial filter method.

For example, when trying to estimate the neural activity current of the spinal cord, since the spinal cord exists in the spinal canal in the spine, it is possible to obtain the positional relationship between the spinal cord and the sensor array from the spinal canal shown in the X-ray image. .. However, when trying to estimate the activity of a nerve such as a peripheral nerve in which the positional relationship between the bone and the nerve is not uniquely determined, it is difficult to obtain the positional relationship between the nerve and the sensor array from the X-ray image, and the nerve activity current is calculated. It is difficult to estimate accurately.

The ultrasonic measuring device can acquire an ultrasonic image including an image of a nerve. However, a method for accurately detecting the position of the subject to which the ultrasonic probe is applied has not been established. Therefore, conventionally, for example, the position where the ultrasonic probe is applied is directly marked on the body surface of the subject. Furthermore, when the ultrasonic probe is pressed against the body surface of the subject, the position of the nerve in the ultrasonic image may deviate from the position of the nerve at the time of acquisition of the biomagnetic field.

The disclosed technique was made in view of the above-mentioned problems, and biomagnetic field data can be specified by making it possible to identify the positional relationship between the position of a nerve and a magnetic sensor at the time of magnetic field measurement by using an ultrasonic image. The purpose is to estimate the current distribution from.

In order to solve the above technical problem, the biomagnetic measuring device of one embodiment of the present invention is separated from the sensor accommodating portion in which the magnetic sensor is housed and the facing surface of the sensor accommodating portion facing the detection unit of the magnetic sensor. A transparent plate member that can be arranged and a measurement target portion that can be acquired by an ultrasonic probe that is applied to the plate member that is in contact with the measurement target portion while the plate member is separated from the facing surface. The measurement measured by the magnetic sensor based on the positional relationship between the nerve and the magnetic sensor obtained from the position information of the nerve and the image including the ultrasonic probe and the plate member at the time of acquiring the position information of the nerve. It is characterized by having a current estimation unit that estimates the current distribution in the measurement target site from the biomagnetic field data of the target site.

The current distribution can be estimated from the biomagnetic field data by making it possible to specify the positional relationship between the position of the nerve and the magnetic sensor at the time of magnetic field measurement by using the ultrasonic image.

It is a block diagram which shows an example of the biomagnetic measurement system which concerns on 1st Embodiment of this invention. It is a block diagram which shows the example of changing the position of a camera in the biomagnetic measurement system of FIG. It is a perspective view which shows an example of the slide structure of the movable plate provided in the protruding part of the Dewar of FIG. It is a perspective view which shows another example of the movable plate provided in the protruding part of the Dewar of FIG. It is a block diagram which shows an example of the function of the biomagnetic measurement system of FIG. It is a flow chart which shows an example of the operation of the biomagnetic measurement system of FIG. 1 and FIG. It is explanatory drawing which shows an example of the ultrasonic image acquired by the ultrasonic measuring apparatus of FIG. 1 and FIG. It is explanatory drawing which shows an example which acquires the positional relationship between a nerve and a magnetic sensor of a sensor array by the positional relationship acquisition part of FIG. It is explanatory drawing which shows an example of the current waveform (the time change of the current intensity) estimated by the current estimation part based on the magnetic field data measured by the magnetic measuring apparatus of FIG. 1 and FIG. It is explanatory drawing which shows the peak intensity of the current waveform shown in FIG. 9 in the order of the waveform number. It is a block diagram which shows an example of the biomagnetic measurement system which concerns on 2nd Embodiment of this invention. It is a perspective view which shows an example of the movable plate provided in the protrusion | protrusion part of the dewar in the biomagnetic measurement system which concerns on 3rd Embodiment of this invention. It is explanatory drawing which shows the example of the evaluation result at the time of acquiring the ultrasonic image of the measurement target part through the sensor facing area of FIG. 12 formed by various materials. It is a figure which shows the example of the ultrasonic image of the measurement target part acquired through the sensor facing area formed by the material of FIG. It is a figure which shows the example of the ultrasonic image of the measurement target part acquired through the sensor facing area formed by the material of FIG. It is a figure which shows the example of the ultrasonic image of the measurement target part acquired through the sensor facing area formed by the material of FIG. It is a figure which shows the example of the ultrasonic image of the measurement target part acquired through the sensor facing area formed by the material of FIG. It is a figure which shows the example of the ultrasonic image of the measurement target part acquired through the sensor facing area formed by the material of FIG. It is a figure which shows the example of the ultrasonic image of the measurement target part acquired through the sensor facing area formed by the material of FIG. It is a block diagram which shows an example of the hardware configuration of the data processing apparatus of FIG. 1, FIG. 2 and FIG.

Hereinafter, embodiments will be described with reference to the drawings. In each drawing, the same components may be designated by the same reference numerals, and duplicate description may be omitted.

(First Embodiment)
FIG. 1 is a system configuration diagram showing an example of a biomagnetic measurement system according to the first embodiment of the present invention. The biomagnetic measurement system 100 shown in FIG. 1 includes a magnetic measurement device 10, a dewar 20, a nerve stimulator 30, an ultrasonic measurement device 40, and a data processing device 50. The magnetic measuring device 10 is an example of a biomagnetic measuring device.

The magnetic measuring device 10 includes a sensor array 11 including a plurality of superconducting QUantum Interference Devices (SQUIDs) and a signal processing device 12. The magnetic measuring device 10 is connected to the data processing device 50, and its operation is controlled by the data processing device 50. The data processing device 50 has a computer such as a server or a PC (Personal Computer), and can execute various data processes by executing a program.

The sensor array 11 is housed inside a protrusion 21 that protrudes from the Dewar 20. For example, the upper surface of the protruding portion 21 has a curved cross-sectional shape. The magnetic detection unit on the tip end side of each magnetic sensor (SQUID sensor) of the sensor array 11 is arranged along the curved inner surface of the protruding portion 21 so as to face the inner surface. The protruding portion 21 is an example of a sensor accommodating portion in which the magnetic sensor of the sensor array 11 is housed.

A guide rail 70 arranged along the projecting direction of the projecting portion 21 is fixed on the projecting portion 21. The guide rail 70 is an example of a guide member. A movable plate 60 is slidably attached to the guide rail 70 in the projecting direction of the projecting portion 21 (lower right direction in the figure, orthogonal direction in the cross section). For example, the movable plate 60 has a curved shape corresponding to the curved shape of the upper surface of the protruding portion 21, and can move on the guide rail 70 so as to slide on the upper surface of the protruding portion 21. The movable plate 60 is an example of a plate member, and the upper surface of the protruding portion 21 is an example of a facing surface facing the magnetic sensor.

For example, the movable plate 60 is a resin plate such as polyethylene terephthalate, and a plate material that is transparent to visible light and allows a magnetic field to pass through is used. The movable plate 60 is preferably colorless and transparent. The material of the movable plate 60 is preferably a non-magnetic material and has an acoustic impedance close to that of the human body. The movable plate 60 may be made of polycarbonate in addition to polyethylene terephthalate. The movable plate 60 is set to a thickness (for example, about 1 mm to 5 mm, preferably about 1 mm to 2 mm) so as not to bend when the ultrasonic probe is pressed. Further, the movable plate 60 may have a thicker peripheral portion (guide rail 70 side) that requires strength than the central portion.

By attaching the guide rail 70 to the protrusion 21, the moving mechanism of the movable plate 60 can be easily constructed as compared with the case where the mechanism for moving the movable plate 60 together with the chair or the bed is provided. Therefore, the guide rail can be easily attached to the magnetic measuring device 10 that is already in operation, and the magnetic measuring device 10 that can acquire an ultrasonic image can be modified to minimize the cost.

The nerve stimulator 30 applies electrical stimulation to the subject via electrodes attached to the body surface of the subject to induce nerve activity of the subject. The nerve stimulator 30 is connected to the data processing device 50, and its operation is controlled by the data processing device 50. In FIG. 1, the description of the cable connected to the nerve stimulator 30 and the electrode for applying electrical stimulation to the subject is omitted. The data processing device 50 can operate the nerve stimulating device 30 and the magnetic measuring device 10 in synchronization with each other.

The ultrasonic measuring device 40 acquires an ultrasonic image of a measurement target region before measuring the biological magnetic field from the subject by the magnetic measuring device 10. As described with reference to FIG. 7, since the ultrasonic image shows the nerve, the position of the nerve can be determined. The ultrasonic measuring device 40 is connected to the data processing device 50, and the ultrasonic image acquired by the ultrasonic measuring device 40 is transferred to the data processing device 50 and can be displayed on the display device 50a of the data processing device 50. Is.

The Dewar 20 including the protrusion 21 and the ultrasonic measuring device 40 are arranged in a magnetic shield chamber 200 that shields magnetism. The magnetic shield room 200 has, for example, an internal space having a width and height of about 2.5 m and a length of about 3 m, and has a door 210 for transporting a Dewar 20 or the like and for people to enter and exit.

In the magnetic shield room 200, a chair 80 on which the subject sits may be arranged near the protrusion 21. In this embodiment, the subject sitting on the chair 80 puts his forearm on the upper surface of the movable plate 60 to bring the front surface (palm side surface) of the elbow into contact with the movable plate 60, and the elbow protrudes through the movable plate 60. It faces the upper surface of the portion 21. At this time, the movable plate 60 is pulled toward the Dewar 20 side.

On the ceiling of the magnetic shield room 200, a camera 300 is installed above the movable plate 60. The camera 300 may be a video camera capable of shooting a moving image, or a digital still camera capable of shooting a still image. The camera 300 is movable with the measurement target portion (forearm) of the subject placed on the movable plate 60 pulled out along the guide rail 70 when the ultrasonic image of the subject is acquired by the ultrasonic measuring device 40. An ultrasonic probe (not shown) visible through the plate 60 is photographed.

The camera 300 is connected to the data processing device 50. The image acquired by the camera 300 is transferred to the data processing device 50 and can be displayed on the display device 50a. When the camera 300 is a digital still camera, the release operation of the camera 300 may be performed by an operator who operates the ultrasonic probe. As a result, the digital still camera can acquire an image at an arbitrary timing intended by the operator (timing at which an appropriate ultrasonic image can be acquired).

FIG. 2 is a block diagram showing an example of changing the position of the camera 300 in the biomagnetic measurement system of FIG. In FIG. 2, the camera 300 is installed not on the ceiling of the magnetic shield room 200 but on the floor surface below the protrusion 21. By installing the camera 300 on the floor surface, it is possible to photograph the measurement site (measurement position) of the subject to which the ultrasonic probe is applied through the transparent movable plate 60.

FIG. 3 is a perspective view showing an example of a slide structure of the movable plate 60 provided on the protruding portion 21 of the Dewar 20 of FIG. In FIG. 3, the description of the subject (forearm) is omitted. The movable plate 60 is pulled toward the Dewar 20 side during the measurement of the biomagnetic field by the magnetic measuring device 10 (FIG. 1) and before the ultrasonic measurement by the ultrasonic measuring device 40 (FIG. 1).

With the movable plate 60 pulled toward the Dewar 20, the subject sits on the chair 80 (FIG. 1), places the forearm on the protrusion 21 (on the movable plate 60), and places the front of the elbow (palm side). It is brought into contact with the movable plate 60. This state is the state at the time of measurement of the biomagnetic field by the magnetic measuring device 10.

Then, while keeping the front surface (palm side surface) of the elbow portion in contact with the movable plate 60, the movable plate 60 slides on the guide rail 70 and moves, and is pulled out to the side opposite to the dewar 20. In this way, the movable plate 60 can be separated from the upper surface of the protrusion 21. The movable plate 60 is moved until it hits the stopper 72 attached to the tip of the guide rail 70. For example, the movable plate 60 is fixed to the stopper 72 by a lock mechanism such as a clasp (latch) (not shown) with the tip of the movable plate 60 in contact with the stopper 72.

Since the movable plate 60 only moves with the arm resting on it, the state of contact with the movable plate 60 on the front surface (palm side surface) of the elbow portion is movable while the movable plate 60 is fixed to the stopper 72. This is the same as when the plate 60 is pulled toward the dewar 20 side. That is, the contact state of the front surface (palm side surface) of the elbow portion with the movable plate 60 is the same as the state at the time of measurement of the biomagnetic field by the magnetic measuring device 10. Then, with the movable plate 60 fixed to the stopper 72, the ultrasonic probe of the ultrasonic measuring device 40 is applied to the back surface (lower side) of the movable plate 60, and the subject is measured via the movable plate 60. Ultrasound images are acquired at multiple locations on the target site.

At this time, the pressing force by the tip of the ultrasonic probe is applied to the back surface of the movable plate 60, but the movable plate 60 does not bend due to the rigidity, and the front surface of the elbow (palm side surface) is in contact with the movable plate 60. Does not change. Therefore, the shape of the measurement target portion of the subject can be maintained in the same state as when the biomagnetic field is measured by the magnetic measuring device 10, and the ultrasonic image can be acquired.

Here, the fact that the shape of the measurement target site of the subject is the same means that the nerve position of the measurement target site is the same when the ultrasonic image is acquired and when the biomagnetic field is measured. The position of the nerve of the measurement target site includes a position in the plane direction facing the movable plate 60 and a position in the depth direction from the movable plate 60. Hereinafter, the position on the surface facing the movable plate 60 is also referred to as an XY position, and the depth from the movable plate 60 (skin) is also referred to as a Z position.

Since the movable plate 60 is transparent, the operator of the ultrasonic probe can easily grasp the position of the ultrasonic probe without looking into the back surface of the movable plate 60. Further, since the movable plate 60 is transparent, the position of the ultrasonic probe can be photographed by the camera 300 installed on the ceiling of the magnetic shield room 200 with the movable plate 60 pulled out, and the image is taken by the camera 300. It can be recognized by the image.

After the ultrasonic image is acquired and the position information indicating the position of the nerve in the measurement target area of the subject is acquired, the lock between the movable plate 60 and the stopper 72 is released. The acquisition of nerve position information will be described with reference to FIG. The ultrasonic image acquired by the ultrasonic measuring device 40 and the image captured by the camera 300 are transferred to the data processing device 50.

Then, while keeping the front surface (palm side surface) of the elbow portion in contact with the movable plate 60, the movable plate 60 is pulled back on the guide rail 70 toward the Dewar 20 side, and the state on the left side in FIG. 3 is obtained. At this time, the movable plate 60 may be fixed to the outer wall surface of the Dewar 20 by, for example, a locking mechanism.

In this state, an electrical stimulus is applied to the subject from the nerve stimulator 30 (FIG. 1), and the magnetic field generated from the nerve in the elbow, which is the measurement target, is measured by the magnetic measuring device 10. The magnetic measuring device 10 transfers biomagnetic field data indicating the measured magnetic field to the data processing device 50. It is preferable that the electrode for applying the electrical stimulation to the subject is attached to the subject in advance before acquiring the ultrasonic image.

The data processing device 50 is based on the nerve position information obtained from the ultrasonic image and the image taken by the camera 300, the position information of the magnetic sensor, and the biomagnetic field data measured by the magnetic measuring device 10. Estimate the active current. Then, the data processing device 50 displays a current waveform or the like indicating the estimated current on the display device 50a. The process of estimating the neural activity current by the data processing device 50 will be described with reference to FIG.

In addition, in FIGS. 1 and 3, the space where the ultrasonic probe enters below the movable plate 60 by moving the movable plate 60 in the horizontal direction along the guide rail 70 extending in the horizontally direction attached to the protrusion 21. An example of acquiring an ultrasonic image was described. However, a vertically extending guide rail may be attached to the Dewar 20 and the movable plate 60 may be moved vertically along the guide rail. In this case, the ultrasonic image is acquired after moving the movable plate 60 upward until a space for the ultrasonic probe is formed below the movable plate 60.

When the movable plate 60 is attached to the Dewar 20 so as to be movable in the vertical direction, the acquisition of the ultrasonic image and the measurement of the biomagnetic field are performed with the subject standing without placing the chair in the magnetic shield room 200. May be good. A chair that moves in the vertical direction in conjunction with the vertical movement of the movable plate 60 may be arranged in the magnetic shield room 200. In this case, the movable plate 60 may be attached to a moving mechanism that moves in the vertical direction together with the chair and may be moved together with the chair. Then, the acquisition of the ultrasonic image and the measurement of the biomagnetic field are performed while the subject is sitting on the chair.

Further, in FIG. 1, the chair 80 may be fixed to a moving mechanism that can move in the horizontal direction in conjunction with the movement of the movable plate 60 in the horizontal direction, and the chair 80 may be moved with the movement of the movable plate 60. In this case, the shape (nerve position) of the front surface (palm side surface) of the elbow portion in contact with the movable plate 60 can be made less likely to change. The movable plate 60, or the moving mechanism that includes the movable plate 60 and is movable in the horizontal or vertical direction, may be moved electrically instead of manually.

As shown in FIG. 4, a marker coil 62 that emits magnetism may be installed on the movable plate 60, and at least one magnetic sensor may be installed on an ultrasonic probe (not shown). Then, the magnetic field generated from the marker coil 62 may be detected by the magnetic sensor of the ultrasonic probe, and the positional relationship between the ultrasonic probe and the movable plate 60 may be calculated based on the detected magnetic field data. In this case, the measurement obtained from the ultrasonic image (nerve image) obtained by the ultrasonic probe and the positional relationship between the ultrasonic probe and the movable plate 60 without installing the camera 300 shown in FIGS. 1 and 2. Based on the positional relationship between the target nerve and the sensor array 11, the current distribution in the measurement target site can be estimated from the biomagnetic field data of the measurement target site measured by the sensor array 11.

FIG. 5 is a block diagram showing an example of the function of the biomagnetic measurement system 100 of FIG. As described above, in the ultrasonic measuring device 40, the ultrasonic probe 42 is placed in a space formed on the lower side (left side in FIG. 5) of the movable plate 60 in a state where the movable plate 60 is moved to the outside of the protrusion 21. Acquires an ultrasonic image of the measured portion of the subject P. Then, the ultrasonic measuring device 40 outputs the acquired ultrasonic image to the data processing device 50 as a morphological image (including a nerve image) of the measurement target region of the biological magnetic field.

When the camera 300 acquires an ultrasonic image, the movable plate 60 and its surroundings are photographed, and the measured portion of the subject P (for example, the forearm), the movable plate 60, and the ultrasonic probe seen through the movable plate 60 are captured. Get an image. Then, the camera 300 outputs the acquired image to the data processing device 50 as probe position information indicating the position of the ultrasonic probe. As shown in FIG. 2, the camera 300 may be installed on the floor surface of the magnetic shield room 200.

The nerve stimulator 30 receives application timing information indicating the application timing of the electrical stimulus from the data processing device 50, and generates the electrical stimulus. The magnetic measuring device 10 measures the magnetic field induced in the nerve of the measured portion of the subject P by the electrical stimulation from the nerve stimulating device 30. The magnetic measuring device 10 outputs the measured magnetic field as magnetic field data to the data processing device 50.

The data processing device 50 includes a position information acquisition unit 52, a positional relationship acquisition unit 54, and a current estimation unit 56. For example, the position information acquisition unit 52, the positional relationship acquisition unit 54, and the current estimation unit 56 function as a bioelectric current estimation device that estimates the neural activity current based on the magnetic field data measured by the magnetic measurement device 10. The position information acquisition unit 52, the positional relationship acquisition unit 54, and the current estimation unit 56 may be realized by a bioelectric current estimation program executed by a CPU (Central Processing Unit) mounted on the data processing device 50.

The position information acquisition unit 52 includes a morphological image (ultrasonic image) of the measurement target area including a nerve image received from the ultrasonic measuring device 40, and an ultrasonic probe 42 taken by the camera 300 when the morphological image is acquired. Receives probe position information including an image showing the XY position. The probe position information includes time information. Then, the position information acquisition unit 52 acquires the position information of the nerve (for example, the XY position and the Z position at a plurality of points on the traveling path of the nerve) based on the morphological image and the probe position information.

As shown in FIG. 4, when the marker coil 62 is installed on the movable plate 60 and the magnetic sensor is installed on the ultrasonic probe, the position information acquisition unit 52 replaces the probe position information from the camera 300. , The probe position information is acquired based on the magnetic field data detected by the magnetic sensor of the ultrasonic probe. Then, the position information acquisition unit 52 acquires the position information of the nerve based on the ultrasonic image including the nerve image received from the ultrasonic measuring device 40 and the probe position information.

The positional relationship acquisition unit 54 determines the positional relationship between the nerve position and the position of each magnetic sensor based on the nerve position information acquired by the position information acquisition unit 52 and the position information of each magnetic sensor of the sensor array 11. Calculate the indicated positional relationship information. For example, the positional relationship acquisition unit 54 has a position (XY position and Z position) of a plurality of points on the nerve on the three-dimensional coordinates and a position (XY position and Z position) of each magnetic sensor on the three-dimensional coordinates. Based on the above, the positional relationship information between the plurality of points on the nerve and each magnetic sensor is calculated.

The position information of each magnetic sensor is acquired in advance by using the design data of the magnetic measuring device 10. For example, for the Z position of the nerve and the Z position of each magnetic sensor, the most protruding Z position of the tips of each magnetic sensor that opposes the curved inner surface of the protruding portion 21 is set to "0" (reference point). The Z coordinate value at the time is shown, and the signed distance from the reference point is shown.

The current estimation unit 56 uses an estimation algorithm such as a spatial filter method based on the positional relationship information between the plurality of nerve points acquired by the positional relationship acquisition unit 54 and each magnetic sensor in the measurement target area. Estimate the neural activity current at the specified measurement point. Then, the current estimation unit 56 outputs current information (current distribution) indicating the estimated neural activity current.

The measurement points designated in the measurement target area may be points on the nerve, or may be a plurality of points included in a predetermined range in the measurement target area. The estimated neural activity current is displayed on the display device 50a of the data processing device 50 as a current waveform indicating a time change, for example, as shown in FIG. 9 described later. When a plurality of points included in a predetermined range in the measurement target area are specified, the direction and intensity of the current flowing in and around the nerve and their temporal changes can be displayed on the display device 50a. Is.

FIG. 6 is a flow chart showing an example of the operation of the biomagnetic measurement system 100 of FIGS. 1 and 2. Steps S12, S16, and S18 of FIG. 6 are nerves generated by the nerve activity of the subject P based on the magnetic field data of the subject P obtained by measuring the biomagnetic field by the sensor array 11 and the nerve image of the subject P. An example of a biomagnetic current estimation method for estimating an active current is shown. Further, steps S12, S16, and S18 in FIG. 6 occur with the neural activity of the subject P based on the magnetic field data of the subject P obtained by measuring the biomagnetic field by the sensor array 11 and the neural image of the subject P. An example of a biomagnetic current estimation program that estimates the neural activity current to be performed is shown.

Before starting the operation of FIG. 6, the measurement target portion of the subject P is placed on the movable plate 60 that is pulled toward the protruding portion 21 side of the Dewar 20. For example, the measurement target site is the elbow. Then, the movable plate 60 is slid to the outside of the protruding portion 21 while keeping the front surface (palm side surface) of the elbow portion in contact with the movable plate 60.

In this state, in step S10, the ultrasonic probe 42 is applied to the inner surface of the movable plate 60, and an ultrasonic image of the measurement target portion of the subject P is acquired through the movable plate 60. Further, an image showing the positional relationship between the ultrasonic probe 42 and the movable plate 60 at the time when the ultrasonic image is acquired is taken by the camera 300.

The acquisition of the ultrasonic image in step S10 is performed by the data processing device 50 controlling the ultrasonic measuring device 40. The acquisition of the position information of the ultrasonic probe 42 in step S10 is performed by the data processing device 50 controlling the camera 300. The data processing device 50 associates the position information of the ultrasonic probe 42 with the ultrasonic image based on the time information output from the camera 300 together with the image and the time information included in the ultrasonic image data.

When the marker coil 62 is installed on the movable plate 60 and the magnetic sensor is installed on the ultrasonic probe 42, instead of taking a picture with the camera 300, the magnetic sensor of the ultrasonic probe 42 is the marker coil installed on the movable plate 60. The magnetic field generated by 62 is detected. Then, the acquisition of the position information of the ultrasonic probe 42 in step S10 is performed based on the magnetic field detected by the magnetic sensor of the ultrasonic probe 42. The data processing device 50 associates the position information of the ultrasonic probe 42 with respect to the movable plate 60 with the ultrasonic image based on the time information included in the ultrasonic image data output from the ultrasonic measuring device 40.

Next, in step S12, the position information acquisition unit 52 acquires the Z position and the XY position at a plurality of nerve locations, respectively. The method of acquiring the Z position of the nerve will be described with reference to FIG. The position information acquisition unit 52 acquires the XY position of the nerve based on the ultrasonic image associated with the time information and the probe position information. The Z position and the XY position are position information of a plurality of locations designated at the time of acquiring the ultrasonic image.

After step S12, the movable plate 60 on which the measurement target portion is placed is returned onto the protrusion 21. The step S12 may be performed after the movable plate 60 is returned onto the protruding portion 21, or may be performed while the movable plate 60 is returned onto the protruding portion 21. Further, step S12 may be performed after step S14 and before step S16 is performed.

Next, in step S14, the magnetic measuring device 10 measures the neural magnetic field in the measurement target region of the subject P. Next, in step S16, the positional relationship acquisition unit 54 has a continuous position based on the position information of the nerve and the sensor array 11 discretely acquired in the measurement target region, for example, by nth-order function approximation. Get information (distance information). For example, the positional relationship acquisition unit 54 receives the Z position and the XY position of the nerve acquired by the position information acquisition unit 52 and the position information of each magnetic sensor of the sensor array 11 acquired in advance. Then, the positional relationship acquisition unit 54 shows the positional relationship between the positions of the plurality of nerves and the positions of the magnetic sensors of the sensor array 11 based on the received Z position and XY position and the position information of each magnetic sensor. Acquire positional relationship information.

Next, in step S18, the current estimation unit 56 uses, for example, a spatial filter method based on the positional relationship information between the positions of a plurality of nerve locations acquired by the positional relationship acquisition unit 54 and the positions of the magnetic sensors. Then, the neural activity current at the specified measurement point is estimated. The estimated neural activity current is displayed on the display device 50a of the data processing device 50, for example, as a current waveform or a current intensity map.

FIG. 7 is an explanatory diagram showing an example of an ultrasonic image acquired by the ultrasonic measuring device 40 of FIGS. 1 and 2. The left side of FIG. 7 shows an ultrasonic image acquired through the movable plate 60 by applying the ultrasonic probe 42 to the inner surface (upper side in FIG. 7) of the movable plate 60. The right side of FIG. 7 shows an ultrasonic image (comparative example) obtained by directly applying the ultrasonic probe 42 to the measurement target site (skin) without passing through the movable plate 60.

The ultrasonic image shown in FIG. 7 was acquired at a position of the forearm of the subject P, which is the measurement target area, and the upper side of FIG. 7 shows the surface of the skin on the front surface (palm side surface) of the elbow. In the present embodiment, for example, about 5 ultrasonic images are acquired in order to calculate the time change of the estimated activity current of the nerve and the conduction speed of the electric signal in the nerve, and FIG. 7 shows one of them. be. Since the ultrasonic image shows subcutaneous tissues such as nerves, blood vessels, and muscles, it is possible to obtain the positional relationship of these tissues and the distance from the surface of the skin.

For example, in an ultrasonic image, the distance (depth) from the surface of the skin to the nerve can be measured by the distance measuring function of the ultrasonic measuring device 40 by designating two positions on the ultrasonic image. Regarding the position of the nerve on the ultrasonic image, the positional relationship with the blood vessel and the positional relationship with the skin are clear for each measurement target area (forearm, etc.). Further, the cross-sectional shape of the nerve in the ultrasonic image is unique to each measurement target region.

However, when the ultrasonic probe 42 is pressed against the skin to acquire an ultrasonic image, the distance of the nerve from the skin surface changes depending on the magnitude of the pressing force on the skin and the like. Further, when the ultrasonic probe 42 is pressed against the skin, the positional relationship between the nerve position and the blood vessel changes. By applying the ultrasonic probe 42 to the skin surface via the movable plate 60, the distance from the skin surface to the nerve, the position of the nerve, and the positional relationship between the nerve and the blood vessel are made the same as when measuring the biomagnetic field. be able to. Therefore, for example, by analyzing an ultrasonic image and obtaining the position of the surface of the skin and the position of the nerve, it is possible to obtain the distance (depth) from the surface of the skin to the nerve. At this time, a machine learning method such as deep learning may be used.

While the ultrasonic image is being acquired by the ultrasonic probe 42, the location of the ultrasonic probe 42 in the measurement target region can be determined by analyzing the image acquired by the camera 300 with the data processing device 50. That is, the probe position information (XY position of the ultrasonic probe 42) can be acquired from the image acquired by the camera 300.

Further, a key mark indicating the center position of the ultrasonic probe 42 is displayed in the upper center of the ultrasonic image. Therefore, the data processing device 50 can acquire the XY position of the nerve on the measurement target region based on the probe position information and the ultrasonic image.

Note that FIG. 7 shows an example in which an ultrasonic probe 42 is applied to the skin surface of the front surface (palm side surface) of the elbow portion of the subject P via a movable plate 60 to acquire an ultrasonic image including a nerve image. However, an ultrasonic probe 42 may be applied to the skin surface on the posterior side (dorsal side surface) of the elbow via a movable plate 60 to acquire an ultrasonic image including a nerve image.

FIG. 8 is an explanatory diagram showing an example in which the positional relationship acquisition unit 54 of FIG. 5 acquires the positional relationship between the nerve and each magnetic sensor of the sensor array 11. The image on the left side of FIG. 8 shows a morphological image including a measurement target region A in a state where the elbow portion of the subject P is placed on the protruding portion 21 of the magnetic measuring device 10. In the image, the elbow side of the forearm is visible, the upper side of the image is the upper arm side, and the lower side of the image is the wrist side. The image on the left side of FIG. 8 is an image in which the measurement target area A, the XY position of the nerve, and the XY position of each magnetic sensor of the sensor array 11 are superimposed on the image taken by the camera 300. When the marker coil 62 is installed on the movable plate 60 and the magnetic sensor is installed on the ultrasonic probe 42, the image on the left side of FIG. 8 shows the measurement target area A, the XY position of the nerve, and the magnetism of the sensor array 11. The image is a superposition of the XY positions of the sensor.

The small circles distributed in a staggered pattern indicate the XY positions of each magnetic sensor in the sensor array 11. The plurality of double circles indicate the XY positions of the nerve and are acquired by the position information acquisition unit 52. The position of the double circle is included in the position where the ultrasonic image is acquired by the ultrasonic probe 42.

In the measurement target area A, a plurality of marker MCs are arranged on the left and right outside of the arrangement area of the sensor array 11. The marker MC is a coil photographed together with the subject P in order to associate a morphological image such as an X-ray image with a measurement position of magnetic field data by the sensor array 11, and a predetermined current is passed through the marker MC.

The positional relationship between the position of the marker MC and each magnetic sensor of the sensor array 11 has been acquired in advance. Therefore, by identifying the position of the marker MC by each magnetic sensor, it is possible to detect that each magnetic sensor is located at a small circle in the figure. The alternate long and short dash line extending in the horizontal direction from the image on the left side of FIG. 8 to the graph on the right side indicates the position where the ultrasonic image was acquired by the ultrasonic measuring device 40 of FIG.

The graph on the right side of FIG. 8 shows the Z position (depth) of the nerve from the surface of the front surface (palm side surface) of the elbow portion of the subject P in and around the measurement target area A, corresponding to the image on the left side. The small circle on the right side indicates the Z position (depth) of the tip of the magnetic sensor. The curve obtained by connecting the small circles on the right side indicates the positions of the surface of the protrusion 21 and the inner surface of the movable plate 60. In the graph on the right, the distance between the Z position of the curve obtained by connecting the circles and the Z position of the nerve indicates the distance from the magnetic sensor to the nerve.

The Z position of the nerve obtained from the ultrasonic image acquired through the movable plate 60 is the same as the Z position of the nerve when measuring the biomagnetic field. Therefore, by acquiring the ultrasonic image via the movable plate 60, the relationship between the Z position of the nerve shown on the right side of FIG. 8 and the Z position of each magnetic sensor can be obtained. That is, it is possible to obtain the relationship between the actual Z position of the nerve and the Z position of each magnetic sensor when measuring the biomagnetic field.

Since the cross section of the surface connecting the movable plate 60 and the tip of the magnetic sensor has a curved cross section, the Z position of the nerve is not based on the "0" point of the Z coordinate, but the Z of the tip of the magnetic sensor. Calculated based on the position. The current estimation unit 56 is designated based on the XY position of the nerve shown on the left side of FIG. 8 and the XY position of each magnetic sensor, and the Z position of the nerve shown on the right side of FIG. 8 and the Z position of each magnetic sensor. The neural activity current at the measurement point (in the example of FIG. 8, the double circle shown on the left side) is estimated.

FIG. 9 is an explanatory diagram showing an example of a current waveform (time change of current intensity) estimated by the current estimation unit 56 based on the magnetic field data measured by the magnetic measuring device 10 of FIGS. 1 and 2. The left side of FIG. 9 shows an image in which the traveling direction of the nerve is superimposed on the X-ray image of the forearm of the subject P for easy explanation, and is used for estimating the nerve activity current by the current estimation unit 56. It's not something. The lower side of the X-ray image is the wrist side.

The solid current waveform on the right side of FIG. 9 shows the time change of the current intensity estimated in consideration of the Z position (distance (depth) from the skin) of the nerve acquired by the position information acquisition unit 52. The broken line current waveform on the right side of FIG. 9 shows the time change (comparative example) of the current intensity estimated assuming that the Z position of the nerve is constant.

The time change of the current intensity shown in FIG. 9 is estimated from the biological magnetic field generated by the current flowing through the nerve axon in response to the electrical stimulation when the wrist side of the forearm is electrically stimulated by the nerve stimulator. The current is transmitted through the nerve axons from the distal side (lower side of FIG. 9) to the proximal side (upper side of FIG. 9). Therefore, in both the solid line current waveform and the broken line current waveform, the time at which the peak intensity of the current appears is delayed toward the nerve on the proximal side. The waveform numbers of the current waveforms are indicated by 1 to 4 from the distal side to the proximal side.

In terms of neurophysiology, the peak intensity of the current waveform is almost constant, or becomes weaker toward the proximal side farther from the position where the electrical stimulus is applied. However, the peak intensity of the broken line current waveform is smaller toward the distal side, and the current intensity cannot be estimated correctly. This is because when the current intensity is estimated assuming that the Z position of the nerve is constant, an error occurs with respect to the actual depth of the nerve, and the error appears as an error when estimating the current intensity from the magnetic field data. Is.

On the other hand, the peak intensity of the solid line current waveform estimated based on the actual Z position of the nerve hardly changes, and it can be judged that the current intensity can be estimated correctly. As described with reference to FIG. 8, by acquiring the ultrasonic image via the movable plate 60, it is possible to obtain the relationship between the actual Z position of the nerve and the Z position of each magnetic sensor when measuring the biomagnetic field. .. Therefore, the current estimation unit 56 can estimate the correct current intensity based on the correct Z position of the nerve, and can obtain the current waveform shown by the solid line.

FIG. 10 is an explanatory diagram showing the peak intensities of the current waveforms shown in FIG. 9 in the order of waveform numbers. The solid line shows the characteristics of the current intensity estimated in consideration of the Z position of the nerve acquired by the position information acquisition unit 52. The broken line shows the characteristic of the current intensity (comparative example) estimated assuming that the Z position of the nerve is constant. In the characteristics of the solid line, the rate of change of the current intensity due to the waveform number indicating the position of the nerve is small. On the other hand, in the characteristic of the broken line, the rate of change of the current intensity depending on the waveform number is large. That is, in the biomagnetic measurement system 100 shown in FIG. 1, by using the movable plate 60, the same nerve position (Z position) as when measuring the biomagnetic current can be obtained from the ultrasonic image, as shown by the solid line. In addition, the estimation accuracy of the current intensity can be improved.

In addition, when a plurality of points for estimating the current intensity are provided on the measurement target area A and the direction of the current flowing in and around the nerve or the current intensity distribution is estimated, the same as the description in FIGS. 9 and 10. In addition, the current intensity can be estimated correctly.

As described above, in this embodiment, by using the transparent movable plate 60, for example, the operator of the ultrasonic probe 42 can grasp the position of the ultrasonic probe 42 without looking into the back surface of the movable plate 60. can. Further, the ultrasonic probe 42 can be photographed through the movable plate 60 by the camera 300 installed on the ceiling or the floor of the magnetic shield room 200. Then, from the image obtained by photographing, the XY position of the ultrasonic probe 42 with respect to the movable plate 60 when the ultrasonic image is acquired can be detected.

Thereby, the Z position and the XY position of the nerve at the time of measuring the biomagnetic field can be detected based on the ultrasonic image and the image acquired by the camera 300. The relationship between the position of the movable plate 60 and the position of each magnetic sensor of the sensor array 11 when measuring the biomagnetic field has been acquired in advance. Therefore, the positional relationship between the nerve position (Z position and XY position) and the position of each magnetic sensor (Z position and XY position) can be detected, and the current of the measurement target site can be detected from the biomagnetic field data based on the positional relationship. The distribution can be estimated. That is, the current distribution in the living body can be estimated from the biomagnetic field data of the peripheral nerve by using the ultrasonic image including the nerve image.

By arranging the movable plate 60 so as to be separable from the protruding portion 21, it is possible to maintain the measurement target portion in the same state as when measuring the biomagnetic field and acquire an ultrasonic image of the measurement target portion. As a result, even when the measurement target site is moved to a place different from that at the time of measuring the biomagnetic field, the position information acquisition unit 52 can detect the same nerve position as at the time of measuring the biomagnetic field. Therefore, the positional relationship acquisition unit 54 can accurately detect the positional relationship between the position of the nerve and the position of each magnetic sensor, and estimate the current distribution in the living body with little error from the biomagnetic field data of the peripheral nerve. be able to.

By attaching the guide rail 70 to the protrusion 21, the moving mechanism of the movable plate 60 can be easily constructed as compared with the case where the mechanism for moving the movable plate 60 together with the chair or the bed is provided. Therefore, the guide rail can be easily attached to the magnetic measuring device 10 that is already in operation, and the magnetic measuring device 10 that can acquire an ultrasonic image can be modified to minimize the cost.

(Second Embodiment)
FIG. 11 is a block diagram showing an example of the biomagnetic measurement system according to the second embodiment of the present invention. The same elements as those in FIGS. 1 and 2 are designated by the same reference numerals, and detailed description thereof will be omitted. The biomagnetic measurement system 102 shown in FIG. 11 has the biomagnetism of FIG. 1 except that it has a bed 90 and a pedestal 92 instead of the chair 80 of FIG. 1 and a guide groove 96 instead of the guide rail 70. It has the same configuration as the measurement system 100. In the biomagnetic measurement system 102, the camera 300 may be installed below the protrusion 21 on the floor surface of the magnetic shield room 200, as in FIG.

A subject (not shown) lies on the bed 90, for example, on his back, with the lower left side of FIG. 11 as his head. The subject is placed on the movable plate 60 with the knee portion lying on the bed 90. That is, in this embodiment, the biomagnetic field generated from the nerve in the knee is measured, and the nerve activity current in the knee is estimated based on the measured magnetic field data. The shapes, structures, and positional relationships between the projecting portion 21 and the movable plate 60 are the same as those in FIGS. 1 and 3.

However, in this embodiment, both sides of the movable plate 60 having a curved cross section in the width direction (attachment portions with the guide rail 70 in FIG. 1) are fixed to the bed 90 via a plate-shaped fixing member 94. There is. The pedestal 92 has a guide groove 96 into which a protrusion provided on the lower surface of the bed 90 is fitted. The guide groove 96 is formed along the protruding direction of the protruding portion 21, and the bed 90 can move in the protruding direction of the protruding portion 21. The guide groove 96 is an example of a guide member. Then, by moving the movable plate 60 together with the movement of the bed 90, the movable plate 60 can be moved in the same manner as in FIG.

The ultrasonic image of the knee portion is acquired by the ultrasonic measuring device 40 in a state where the bed 90 is moved to the side opposite to the Dewar 20 and the movable plate 60 is moved to the outside of the protruding portion 21. At this time, as in the above-described embodiment, the camera 300 takes an image showing the positional relationship between the ultrasonic probe and the movable plate 60. After that, the bed 90 is moved to the Dewar 20 side until the movable plate 60 is located on the protruding portion 21 (on the sensor array 11), and the biomagnetic field of the knee portion is measured by the magnetic measuring device 10.

The function of the biomagnetic measurement system 102 is the same as that of FIG. 5, except that the movable plate 60 of FIG. 5 moves in conjunction with the bed 90. The operation of the biomagnetic measurement system 102 and the acquired images, waveforms, and the like are the same as those described in FIGS. 6 to 10.

As described above, in this embodiment, the same effect as that of the above-described embodiment can be obtained. Further, in this embodiment, by providing a mechanism for moving the movable plate 60 together with the bed 90, the position of the nerve in the knee portion of the subject and the position of the sensor array 11 are determined as compared with the case where the movable plate 60 is not used. The relationship can be accurately acquired using an ultrasonic image. This makes it possible to accurately estimate the active current of the nerve in the knee based on the measurement of the biomagnetic field generated from the nerve in the knee, as compared with the case where the movable plate 60 is not used.

In addition, in FIG. 11, an example in which the movable plate 60 can be moved horizontally together with the bed 90 has been described. However, a mechanism for vertically moving the bed 90 may be provided on the pedestal 92 so that the movable plate 60 can be vertically moved together with the bed 90. In this case, after moving the movable plate 60 upward until a space for the ultrasonic probe is formed below the movable plate 60, an ultrasonic image of the lower part of the knee is acquired.

(Third Embodiment)
FIG. 12 is a perspective view showing an example of a movable plate provided on a protruding portion of the Dewar in the biomagnetic measurement system according to the third embodiment of the present invention. The same elements as those in the above-described embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.

The movable plate 60A shown in FIG. 12 is slidably attached to the guide rail 70 instead of the movable plate 60 shown in FIGS. 1, 2 and 11. The biomagnetic measurement system of this embodiment is the same as the biomagnetic measurement systems 100 and 102 shown in FIGS. 1, 2 and 11 except for the structure of the movable plate 60A. As in FIG. 4, the marker coil 62 may be installed on the movable plate 60A.

In the movable plate 60A, the structure of the sensor facing region 61A located at the center of the movable plate 60A is different from the structure of the sensor facing region of the movable plate 60 shown in FIG. 3 and the like. The sensor facing region 61A is provided at a position facing the tip end side of the sensor array 11 in a state where the movable plate 60A is pulled toward the Dewar 20 side.

The sensor facing region 61A is an region where the ultrasonic probe 42 of the ultrasonic measuring device 40 (FIG. 5) is applied from the back surface side (lower side) while the movable plate 60A is pulled out along the guide rail 70. The sensor facing region 61A may be provided in a region to which the ultrasonic probe 42 is applied, and may be smaller than the region of the facing portion of the sensor array 11.

The sensor facing region 61A of the movable plate 60A is formed of a material or shape that makes it easy to acquire an ultrasonic image by the ultrasonic probe 42. For example, the thickness of the sensor facing region 61A of the movable plate 60A is preferably thinner than the thickness around the sensor facing region 61A of the movable plate 60A. An example of the material and thickness of the sensor facing region 61A is shown in FIG.

It should be noted that the material and thickness around the sensor facing region 61A in the movable plate 60A are rigid enough not to be deformed with respect to the weight of the measurement target portion of the subject P placed on the movable plate 60A. It may be formed of a material different from the material of the sensor facing region 61A. At this time, the material around the sensor facing region 61A in the movable plate 60A is preferably transparent to visible light.

FIG. 13 is an explanatory diagram showing an example of an evaluation result when an ultrasonic image of a measurement target portion is acquired through the sensor facing region 61A of FIG. 12 formed of various materials. FIG. 13 shows an example in which an ultrasonic image of the median nerve of the wrist joint and the elbow and an ultrasonic image of the sural nerve at a position 8 cm or 12 cm away from the ankle joint are acquired. The median nerve is thicker than the sural nerve.

12 MHz and 22 MHz indicate the frequency of the ultrasonic probe 42. The resolution of the ultrasonic probe 42 decreases as the frequency decreases, but it easily reaches the deep part of the body. To acquire an ultrasonic image, the measurement target part of the upper limb or lower limb is placed on the movable plate 60A, and with the movable plate 60A pulled out, ultrasonic waves are emitted from the lower side of the movable plate 60A to the measurement target part via the sensor facing region 61A. This is done by hitting the probe 42.

In FIG. 13, the circles indicate that the image quality (visibility) of the ultrasonic image is good, and the triangular marks indicate that the image quality of the ultrasonic image is slightly good. The X mark indicates that the image quality of the ultrasonic image is poor, and the "-" indicates that it has not been evaluated.

The evaluation shown in FIG. 13 confirmed that the materials having good visibility of the median nerve and the sural nerve on the ultrasonic image were ABS (Acrylonitrile Butadiene Styrene) resin, polystyrene and polycarbonate having a thickness of 1 mm. Further, in the case of ABS resin, it was confirmed that the visibility of the median nerve and the sural nerve on the ultrasonic image was good even with a thickness of 2 mm.

The movable plate 60A is not limited to the above-mentioned structure, and may be any one that can acquire an ultrasonic image of a measurement target portion of the subject P placed on the movable plate 60A. For example, slits or holes may be provided in the sensor facing region 61A of the movable plate 60A at predetermined intervals. Further, when the area of the measurement target portion is small, an opening may be provided in the sensor facing region 61A according to the measurement target portion.

Further, when the area of the measurement target portion is small and the strength of the sensor facing region 61A is not required, the sensor is made of a material having an acoustic impedance close to the acoustic impedance of the human body (for example, a gel material) instead of a solid material such as resin. The facing region 61A may be formed.

14 to 19 are diagrams showing an example of an ultrasonic image of a measurement target portion acquired through the sensor facing region 61A formed of the material of FIG. 13. A key mark indicating the center position of the ultrasonic probe 42 is displayed in the upper center of each ultrasonic image.

As described with reference to FIG. 5, the ultrasonic image of the measurement target portion of the subject P shows the lower side of the sensor facing region 61A of the movable plate 60A in a state where the movable plate 60A is moved to the outside of the protruding portion 21. It is acquired by an ultrasonic probe 42 that is placed in a space that can be formed. In each ultrasound image, nerves are present at the positions indicated by the white dashed circles.

FIG. 14 is an ultrasonic image acquired through the sensor facing region 61A formed of 1 mm thick ABS resin. FIG. 15 is an ultrasonic image acquired through a sensor facing region 61A formed of 2 mm thick ABS resin. FIG. 16 is an ultrasonic image acquired through a sensor facing region 61A made of polystyrene having a thickness of 1 mm.

FIG. 17 is an ultrasonic image acquired through a sensor facing region 61A formed of 1 mm thick polycarbonate. FIG. 18 is an ultrasonic image acquired by opening a portion corresponding to a measurement target portion in the sensor facing region 61A. FIG. 19 is an ultrasonic image acquired through a sensor facing region 61A formed of a 1 mm thick acrylic resin.

14 to 17 are ultrasonic images in which the evaluation results were good (circles) in FIG. 13, and the nerves indicated by the broken white circles are clearly visible. In the ultrasonic image acquired by forming an opening in the sensor facing region 61A of FIG. 18, since the ultrasonic probe 42 is directly applied to the measurement target site, a nerve image can be clearly acquired. On the other hand, for example, in the ultrasonic image acquired through the 1 mm thick acrylic resin shown in FIG. 19, the nerves indicated by the broken white circles can hardly be identified.

As described above, in this embodiment, the same effect as that of the above-described embodiment can be obtained. Further, in this embodiment, it is possible to acquire an ultrasonic image of a measurement target portion having good image quality (visibility) while maintaining the strength (rigidity) of the movable plate 60A. As a result, the positional relationship between the position of the nerve and the position of each magnetic sensor can be reliably detected based on the ultrasonic image and the image acquired by the camera 300 shown in FIG. Based on this, the current distribution of the measurement target site can be estimated from the biomagnetic field data. That is, the current distribution in the living body can be estimated from the biomagnetic field data of the peripheral nerve by using the ultrasonic image including the nerve image.

FIG. 20 is a block diagram showing an example of the hardware configuration of the data processing device 50 of FIGS. 1, 2, and 11. For example, the data processing device 50 includes a CPU 501, a RAM 502, a ROM 503, an auxiliary storage device 504, an input / output interface 505, and a display device 50a, which are connected to each other by a bus 507.

The CPU 501 controls the overall operation of the data processing device 50. The CPU 501 realizes the functions of the position information acquisition unit 52, the positional relationship acquisition unit 54, and the current estimation unit 56 by executing the bioelectric current estimation program stored in the ROM 503 or the auxiliary storage device 504. The CPU 501 may control the operation of the biomagnetic measurement system 100 such as the magnetic measurement device 10 and the ultrasonic measurement device 40.

The RAM 502 is used as a work area of the CPU 501, and stores a bioelectric current estimation program and various parameters such as the Z position and the XY position. The ROM 503 stores the bioelectric current estimation program.

The auxiliary storage device 504 is a storage device such as an SSD (Solid State Drive) or an HDD (Hard Disk Drive). For example, the auxiliary storage device 504 stores a control program such as an OS (Operating System) that controls the operation of the data processing device 50, an ultrasonic image, a morphological image data, various parameters, and the like.

The input / output interface 505 is connected to a mouse, a keyboard, and the like. The input / output interface 505 may include a communication interface for communicating with other devices. The display device 50a displays a window for displaying the current waveform shown in FIG. 9 and an operation window. The display device 50a may display an ultrasonic image shown on the left side of FIG. 7 or a diagram showing a positional relationship between the nerve and the sensor array 11 shown in FIG.

Although the present invention has been described above based on each embodiment, the present invention is not limited to the requirements shown in the above embodiments. With respect to these points, the gist of the present invention can be changed without impairing the gist of the present invention, and can be appropriately determined according to the application form thereof.

10 Magnetic measuring device 11 Sensor array 12 Signal processing device 20 Dewar 21 Protruding part 30 Nerve stimulator 40 Ultrasonic measuring device 42 Ultrasonic probe 50 Data processing device 50a Display device 52 Position information acquisition unit 54 Positional relationship acquisition unit 56 Current estimation unit 60, 60A Movable plate 61A Sensor facing area 62 Marker coil 70 Guide rail 72 Stopper 80 Chair 90 Bed 92 Pedestal 94 Fixing member 96 Guide groove 100, 102 Biomagnetic measurement system 200 Magnetic shield room 210 Door 300 Camera 501 CPU
502 RAM
503 ROM
504 Auxiliary storage device 505 Input / output interface 507 Bus A Measurement target area MC Marker P Subject

Japanese Patent No. 4834076 Japanese Patent No. 3094988 JP-A-2019-98156

Seiichi Hisamoto, Masatoshi Higuchi, Examination of body limb cross-section observation method by ultrasonic echo method using water tank, Journal of Biomechanism Society, vol. 34, No. 1 (2010)

Claims (7)

The sensor compartment where the magnetic sensor is stored and the sensor compartment
A transparent plate member that is separably arranged on a facing surface facing the detection unit of the magnetic sensor in the sensor storage unit, and a transparent plate member.
With the plate member separated from the facing surface, the position information of the nerve of the measurement target site and the position information of the nerve that can be acquired by the ultrasonic probe applied to the plate member in contact with the measurement target site. Based on the positional relationship between the nerve and the magnetic sensor obtained from the image including the ultrasonic probe and the plate member at the time of acquisition of the above, the measurement target part is obtained from the biomagnetic current data of the measurement target part measured by the magnetic sensor. A biomagnetic measuring device characterized by having a current estimation unit that estimates the current distribution inside. The biomagnetic measuring apparatus according to claim 1, further comprising a guide member attached to the sensor accommodating portion and guiding the plate member moving along the facing surface. The nerve image included in the morphological image of the measurement target portion acquired by the ultrasonic probe, and the ultrasonic probe and the plate member photographed from above or below the facing surface at the time of acquiring the morphological image are included. Based on the image, a position indicating the position of the nerve on the facing surface and the depth of the nerve from the facing surface when the plate member in contact with the measurement target site is opposed to the facing surface. The location information acquisition unit that acquires information, and
Positional relationship acquisition to acquire the positional relationship between the nerve and the magnetic sensor based on the position information of the nerve acquired by the position information acquisition unit and the position information of the magnetic sensor with respect to the plate member facing the facing surface. With a part,
The biomagnetic measurement according to claim 1 or 2, wherein the current estimation unit estimates a neural activity current based on the positional relationship acquired by the positional relationship acquisition unit and the biomagnetic field data. Device. The sensor compartment where the magnetic sensor is stored and the sensor compartment
A transparent plate member which is arranged so as to be separated from the facing surface of the sensor accommodating portion facing the detection portion of the magnetic sensor and provided with a plurality of marker coils.
With the plate member separated from the facing surface, the position information of the nerve of the measurement target site that can be acquired by the ultrasonic probe applied to the plate member in contact with the measurement target site, and the ultrasonic probe. Based on the positional relationship between the nerve and the magnetic sensor obtained from the positional relationship between the ultrasonic probe and the plate member acquired based on the magnetic field generated from the marker coil measured by the provided magnetic sensor, A biomagnetic measuring device having a current estimation unit that estimates a current distribution in the measurement target part from biomagnetic field data of the measurement target part measured by the magnetic sensor. The plate member is any one of claims 1 to 4, wherein at least a part thereof is made of a material capable of acquiring the position information of the nerve of the subject by the ultrasonic probe. The biomagnetic measuring device according to the above. Any of claims 1 to 4, wherein at least a part of the plate member is provided with an opening in a region where the position information of the nerve of the subject is to be acquired by the ultrasonic probe. The biomagnetic measuring device according to item 1. Biomagnetic measurement having a dewar including a sensor accommodating portion for accommodating a magnetic sensor, an ultrasonic measuring apparatus including an ultrasonic probe, and a camera installed above or below the sensor accommodating portion. In the system
The biomagnetic measuring device is
A transparent plate member that is separably arranged on a facing surface facing the detection unit of the magnetic sensor in the sensor storage unit, and a transparent plate member.
With the plate member separated from the facing surface, the position information of the nerve of the measurement target site and the position information of the nerve that can be acquired by the ultrasonic probe applied to the plate member in contact with the measurement target site. Based on the positional relationship between the nerve and the magnetic sensor obtained from the image including the ultrasonic probe and the plate member at the time of acquisition of the above, the measurement target part is obtained from the biomagnetic current data of the measurement target part measured by the magnetic sensor. A biomagnetic measurement system characterized by having a current estimation unit that estimates the current distribution inside.

Images