JP2021146121A - Bioelectric current estimation method, bioelectric current estimation device and biomagnetism measurement system - Google Patents

Abstract

To acquire the positional relation between a sensor for measuring a biomagnetic field and a nerve using a nerve image included in an image of a measurement target area, and estimate a nerve activity current generated by the nerve activity of a subject.SOLUTION: A bioelectric current estimation method for estimating a neural activity current generated by the neural activity of a subject based on magnetic field data of the subject obtained by measurement with a magnetic sensor and a nerve image of the subject includes: acquiring position information of a nerve in a measurement target area based on the nerve image included in a morphological image of the measurement target area of the subject for which the magnetic field data is measured; acquiring a positional relation between the position of the nerve and the position of the magnetic sensor based on the acquired position information of the nerve and the position information of the magnetic sensor when facing the measurement target area; and estimating a neural activity current based on the acquired positional relation and the magnetic field data of the measurement target area measured by the magnetic sensor.SELECTED DRAWING: Figure 1

Description

The present invention relates to a bioelectric current estimation method, a bioelectric current estimation device, and a biomagnetic measurement 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 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 disclosed technique was made in view of the above-mentioned problems, and the positional relationship between the sensor for measuring the biomagnetic current and the nerve is acquired by using the nerve image included in the image of the measurement target area, and the subject is subjected to. The purpose is to estimate the neural activity current generated by the neural activity of.

In order to solve the above technical problem, the bioelectric current estimation method of one embodiment of the present invention accompanies the neural activity of the subject based on the magnetic field data of the subject obtained by the measurement by the magnetic sensor and the neural image of the subject. It is a bioelectric current estimation method that estimates the generated neural activity current, and acquires the position information of the nerve in the measurement target area based on the nerve image included in the morphological image of the measurement target area of the subject for which the magnetic field data is measured. Then, based on the acquired position information of the nerve and the position information of the magnetic sensor when facing the measurement target area, the positional relationship between the position of the nerve and the position of the magnetic sensor was acquired and acquired. It is characterized in that the neural activity current is estimated based on the positional relationship and the magnetic field data of the measurement target region measured by the magnetic sensor.

It is possible to acquire the positional relationship between the sensor that measures the biomagnetic field and the nerve using the nerve image included in the image of the measurement target area, and estimate the nerve activity current generated by the nerve activity of the subject. can.

It is a block diagram which shows an example of the biomagnetic measurement system which concerns on one Embodiment of this invention. It is a flow chart which shows an example of the operation of the biomagnetic measurement system of FIG. It is explanatory drawing which shows an example of the ultrasonic image acquired by the ultrasonic wave measuring part of FIG. It is explanatory drawing which shows an example which acquires the positional relationship between a nerve and a sensor part 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 field measurement part of FIG. It is explanatory drawing which shows the peak intensity of the current waveform shown in FIG. 5 in the order of the waveform number. It is a block diagram which shows an example of the hardware composition of the bioelectric current estimation apparatus of 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.

FIG. 1 is a block diagram showing an example of a biomagnetic measurement system according to an embodiment of the present invention. The biomagnetic measurement system 100 shown in FIG. 1 includes a magnetic field measurement unit 10, an ultrasonic measurement unit 20, and a biocurrent estimation device 30. The bioelectric current estimation device 30 includes a position information acquisition unit 32, a positional relationship acquisition unit 34, and a current estimation unit 36.

For example, the magnetic field measurement unit 10 is included in a biomagnetic measurement device installed in a magnetic shield room (not shown), and the biocurrent estimation device 30 is a PC (Personal Computer), a server, or the like installed outside the magnetic shield room. Included in the computer. The bioelectric current estimation device 30 may be realized by a bioelectric current estimation program executed by a CPU (Central Processing Unit) mounted on a computer.

The magnetic field measuring unit 10 has a magnetic sensor 12 and a cover member 16 that covers the tip of the magnetic sensor 12. The magnetic sensor 12 has a plurality of sensor units 14 arranged in an array for measuring the magnetic field of the subject P. The cover member 16 is arranged at a position covering the tip of the sensor unit 14, and has a curved cross section. Here, the surface of the figure corresponds to the cross section, and the depth direction of the figure corresponds to the vertical direction. The plurality of sensor units 14 are installed so that the positions of the tips facing the subject P are curved along the shape of the cover member 16.

For example, the sensor unit 14 has a superconducting QUantum Interference Device (SQUID). That is, the magnetic sensor 12 is a SQUID sensor array. Hereinafter, the plurality of sensor units 14 are also referred to as sensor arrays 14. Then, the magnetic field measuring unit 10 measures the magnetic field induced in the nerve to be measured of the subject P by the electrical stimulation by a nerve stimulating device (not shown). The magnetic field measuring unit 10 outputs the measured magnetic field as magnetic field data to the bioelectric current estimation device 30.

For example, the ultrasonic measurement unit 20 is an ultrasonic inspection device having an ultrasonic probe 22, and may be installed inside or outside the magnetic shield room. Since the ultrasonic image inspection device is an image inspection method in which ultrasonic waves are applied to an object and the echo is visualized, it is possible to directly visually confirm a nerve image showing a nerve that cannot be obtained by X-ray photography. .. The ultrasonic measurement unit 20 outputs a morphological image of the subcutaneous tissue obtained by measuring the measurement target area to the bioelectric current estimation device 30. For example, when the ultrasonic measuring unit 20 measures an ultrasonic image of the subcutaneous tissue of the forearm, the morphological information output to the bioelectric current estimation device 30 includes a nerve image of the forearm.

Here, the measurement target region is a region facing the sensor array 14 in the subject P, and is a region A for acquiring the magnetic field data indicated by the XY coordinates on the left side of FIG. Hereinafter, an arbitrary position (two-dimensional position) on the measurement target area is also referred to as an XY position. Further, in the measurement target region, the position in the direction orthogonal to the body surface of the subject P (for example, the position in the nerve depth direction with respect to the skin surface) corresponds to the Z coordinate on the right side of FIG. Also called position. For example, the body surface of the subject P in the measurement target region is the surface of the measurement target region.

The ultrasonic measurement unit 20 outputs ultrasonic waves from the ultrasonic probe 22 toward the measurement target area of the subject P, and receives the echo from the subject P to receive the subcutaneous tissue of the measurement target area of the subject P. Acquire images (morphological information) of (muscles, nerves, bones, etc.).

When the ultrasonic measurement unit 20 is installed in the magnetic shield room, when the magnetic field data of the subject P in the magnetic shield room is measured by the magnetic field measurement unit 10, the ultrasonic measurement unit 20 is super-measured in the measurement target area of the subject P. The ultrasonic image is taken by the ultrasonic measuring unit 20. On the other hand, when the ultrasonic measuring unit 20 is installed outside the magnetic shield room, for example, the ultrasonic measuring unit 20 measures the magnetic field data of the subject P at a timing different from that of the magnetic field measuring unit 10. An ultrasonic image of the measurement target area is taken.

In this embodiment, the nerve for which the magnetic field is measured is a peripheral nerve. For example, when acquiring the nerve activity current generated by nerve activity by measuring the magnetic field data of the peripheral nerve of the forearm of the subject P, the magnetic field is in contact with the cubital fossa portion of the forearm. The magnetic field data is measured by the measuring unit 10. Further, the ultrasonic probe 22 is applied to the cubital fossa of the forearm, and an ultrasonic image of the subcutaneous tissue of the cubital fossa is acquired.

The biomagnetic measurement system 100 may have a magnetic resonance tomography apparatus instead of the ultrasonic measurement unit 20. In this case, the position information acquisition unit 32 receives the MR (Magnetic Resonance) image received from the magnetic resonance tomography apparatus as a morphological image of the measurement target region including the nerve image instead of the ultrasonic image, and the position of the nerve. Get information.

In the bioelectric current estimation device 30, the position information acquisition unit 32 determines the morphological image of the measurement target region including the nerve image received from the ultrasonic measurement unit 20 and the XY position of the ultrasonic probe 22 when each morphological image is acquired. Receives the indicated probe position information. The probe position information includes time information. Then, the position information acquisition unit 32 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. Instead of receiving the probe position information, the position information acquisition unit 32 may receive the form image in which the probe position information is added to the form image acquired by the ultrasonic measurement unit 20.

The positional relationship acquisition unit 34 is based on the nerve position information acquired by the position information acquisition unit 32 and the position information of each sensor unit 14 of the magnetic sensor 12, and the position of the nerve and the position of each sensor unit 14. Get a relationship. For example, the positional relationship acquisition unit 34 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 sensor unit 14 on the three-dimensional coordinates. ), And the positional relationship between the plurality of points on the nerve and each sensor unit 14 is acquired.

The position information of each sensor unit 14 of the magnetic sensor 12 is acquired in advance by using the design data of the magnetic field measurement unit 10 and the like. The Z position of the nerve and the Z position of each sensor unit 14 indicate the Z coordinate values when the Z position of the most protruding reference point on the surface of the cover member 16 is "0", and are coded from the reference point. Indicates the distance.

The current estimation unit 36 uses an estimation algorithm such as the spatial filter method based on the positional relationship between the plurality of nerve points acquired by the positional relationship acquisition unit 34 and each sensor unit 14, and is within the measurement target area. Performs arithmetic processing (calculation processing) to specify the estimated current of nerve activity at the specified measurement point. Then, the current estimation unit 36 outputs current information 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 a display screen of a data processing device including the bioelectric current estimation device 30 as a current waveform indicating a time change, for example, as shown in FIG. 5 described later. When multiple points within a predetermined range within the measurement target area are specified, it is possible to display the direction or intensity distribution of the current flowing around the nerve and the nerve and their temporal changes on the display screen. Is.

FIG. 2 is a flow chart showing an example of the operation of the biomagnetic measurement system 100 of FIG. In steps S12, S16, and S18 of FIG. 2, the neural activity current generated by the neural activity of the subject P is calculated based on the magnetic field data of the subject P obtained by the measurement by the magnetic sensor 12 and the neural image of the subject P. An example of the bioelectric current estimation method to be estimated is shown. Further, in steps S12, S16, and S18 of FIG. 2, the neural activity generated by the neural activity of the subject P based on the magnetic field data of the subject P obtained by the measurement by the magnetic sensor 12 and the neural image of the subject P. An example of a bioelectric current estimation program for estimating current is shown.

First, in step S10, the ultrasonic probe 22 is applied to the skin of the measurement target region of the subject P and moved along the traveling direction of the nerve, so that the ultrasonic measurement unit 20 is the measurement target including the nerve. Generates an ultrasonic image (morphological image) of the area.

At this time, probe position information indicating the locus of movement of the ultrasonic probe 22 is recorded together with the ultrasonic image. The probe position information can be synchronized with the ultrasonic image based on the time information, for example, by extracting the region including the measurement target region from the image taken by the camera from above the ultrasonic probe 22.

Next, in step S12, the position information acquisition unit 32 acquires the Z position and the XY position at each of the plurality of nerve locations based on the ultrasonic image. The method of acquiring the Z position of the nerve will be described with reference to FIG. The position information acquisition unit 32 acquires the XY position of the nerve based on the ultrasonic image and the probe position information associated with each other by the time information. The Z position and the XY position are the position information of a plurality of places specified at the time of acquiring the ultrasonic image, or the position information of a plurality of places set by the position information acquisition unit 32 at equal intervals on the traveling path of the nerve. be.

Next, in step S14, the magnetic field measuring unit 10 measures the neural magnetic field in the measurement target region of the subject P. Next, in step S16, the positional relationship acquisition unit 34 has a continuous position based on the position information of the nerve and the sensor array 14 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 34 has a plurality of nerve locations based on the Z position and XY position of the nerve acquired by the position information acquisition unit 32 and the position information of each sensor unit 14 of the magnetic sensor 12 acquired in advance. Acquires the positional relationship between the position of the sensor unit 14 and the position of each sensor unit 14.

Next, in step S18, the current estimation unit 36 uses, for example, a spatial filter method based on the positional relationship between the positions of a plurality of nerve locations acquired by the positional relationship acquisition unit 34 and the positions of each sensor unit 14. Then, the neural activity current at the specified measurement point is estimated. The estimated neural activity current is displayed on a display screen of a data processing device including the biocurrent estimation device 30 as, for example, a current waveform or a current intensity map.

FIG. 3 is an explanatory diagram showing an example of an ultrasonic image acquired by the ultrasonic measuring unit 20 of FIG. As described above, the ultrasonic image is acquired by moving the ultrasonic probe 22 along the traveling direction of the nerve while the ultrasonic probe 22 is in contact with the surface of the skin in the measurement target region of the subject P.

The ultrasonic image shown in FIG. 3 was acquired at a position of the forearm of the subject P, which is the measurement target area, and the upper side of FIG. 3 shows the surface of the skin of the cubital fossa. 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. 3 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.

In each ultrasonic image, the distance (depth) from the surface of the skin to the nerve can be measured by the distance measurement function 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. Therefore, the distance (depth) from the surface of the skin to the nerve may be obtained by analyzing the ultrasonic image and obtaining the position of the surface of the skin and the position of the nerve. At this time, a machine learning method such as deep learning may be used.

Further, it is clear where the ultrasonic probe 22 is applied to the measurement target area while the ultrasonic image is being acquired by the ultrasonic probe 22, and as described in FIG. 2, the probe position information (probe position information ( The XY position of the ultrasonic probe 22) can be obtained. Further, a key mark indicating the center position of the ultrasonic probe 22 is displayed in the upper center of the ultrasonic image. Therefore, it is possible to determine the XY position of the nerve on the measurement target region based on the probe position information and the ultrasonic image. The probe position information is acquired by marking the position of the ultrasonic probe 22 on the skin while acquiring an ultrasonic image by the ultrasonic measuring unit 20, and then photographing the measurement target area including the mark with a camera. You may.

FIG. 3 shows an example in which an ultrasonic probe 22 is applied to the skin surface of the front surface (palm side surface) of the elbow portion of the subject P to acquire an ultrasonic image including a nerve image, but the posterior surface of the elbow portion (dorsal side surface). An ultrasonic probe 22 may be applied to the surface of the skin to obtain an ultrasonic image including a nerve image.

FIG. 4 is an explanatory diagram showing an example in which the positional relationship acquisition unit 34 of FIG. 1 acquires the positional relationship between the nerve and the sensor unit 14. The image on the left side of FIG. 4 shows a morphological image including the measurement target area A in a state where the cubital fossa of the forearm of the subject P is placed on the cover member 16 of the magnetic field measurement unit 10, and 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. 4 is an image in which the measurement target area A, the XY position of the nerve, and the XY position of the sensor array 14 are superimposed on the image taken from the information good for the camera.

The small circles dispersed in a staggered pattern indicate the XY position of the sensor unit 14 of the magnetic field measurement unit 10. The plurality of double circles indicate the XY positions of the nerve and are acquired by the position information acquisition unit 32. The position of the double circle is also the position where the ultrasonic image is acquired by the ultrasonic probe 22.

In the measurement target area A, a plurality of markers MK are arranged on the left and right outside of the arrangement area of the sensor unit 14. The marker MK 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 magnetic sensor 12, and a predetermined current is passed through the marker MK.

The positional relationship between the position of the marker MK and each sensor unit 14 has been acquired in advance. Therefore, by identifying the position of the marker MK by the magnetic sensor 12, it is possible to detect that each sensor unit 14 is located at a small circle in the drawing. The alternate long and short dash line extending in the horizontal direction from the image on the left side of FIG. 4 to the graph on the right side indicates the position where the ultrasonic image is acquired by the ultrasonic measuring unit 20 of FIG.

The graph on the right side of FIG. 4 shows the Z position (depth) of the nerve from the body surface of the front surface (palm side surface) of the elbow of the subject P in the measurement target area A and its surroundings, 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 sensor unit 14. The curve obtained by connecting the small circles on the right side indicates the position of the surface of the cover member 16.

When the biomagnetic field is measured by the magnetic field measuring unit 10, the front surface (palm side surface) of the elbow portion of the subject P is brought into contact with the cover member 16. Therefore, in the graph on the right side, 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 surface of the skin to the nerve. The value obtained by adding the distance from the surface of the skin to the nerve and the distance between the surface of the cover member 16 and the tip of the sensor unit 14 indicates the distance from the tip of the sensor unit 14 to the nerve.

Since the cross section of the surface of the cover member 16 and the surface connecting the tips of the sensor portions 14 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 nerve. The correction is made according to the difference between the position and the Z position at the tip of the sensor unit 14. At this time, the Z position of the nerve may be corrected in consideration of the gap between the surface of the cover member 16 and the tip of the sensor portion 14 and the thickness of the cover member 16.

The current estimation unit 36 is based on the XY position of the nerve shown on the left side of FIG. 4 and the XY position of each sensor unit 14, and the Z position of the nerve and the Z position of each sensor unit 14 shown on the right side of FIG. The neural activity current at the specified measurement point (double circle in the example of FIG. 4) is estimated.

FIG. 5 is an explanatory diagram showing an example of a current waveform (time change of current intensity) estimated by the current estimation unit 36 based on the magnetic field data measured by the magnetic field measurement unit 10 of FIG. The left side of FIG. 5 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 36. 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. 5 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 32. The broken line current waveform on the right side of FIG. 5 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. 5 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. 5) to the proximal side (upper side of FIG. 5). 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 is when the arithmetic processing for estimating the current intensity from the magnetic field data is executed. This is because it appears as an error of.

On the other hand, the peak intensity of the solid line current waveform estimated based on the actual Z position of the nerve has hardly changed, and the current intensity is correctly estimated by arithmetic processing using an estimation algorithm such as the spatial filter method. It can be judged that it is.

FIG. 6 is an explanatory diagram showing the peak intensities of the current waveforms shown in FIG. 5 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 32. 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, the estimation accuracy of the current intensity can be improved by considering the Z position, which is the distance from the surface of the skin to the nerve.

When a plurality of points for estimating the current intensity are provided on the measurement target region 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. 5 and 6. In addition, the current intensity can be estimated correctly.

FIG. 7 is a block diagram showing an example of the hardware configuration of the bioelectric current estimation device 30 of FIG. For example, the bioelectric current estimation device 30 is a data processing device (information processing device) and includes a CPU 301, a RAM 302, a ROM 303, an auxiliary storage device 304, an input / output interface 305, and a display device 306, which are mutually connected by a bus 307. It is connected to the.

The CPU 301 controls the overall operation of the bioelectric current estimation device 30. The CPU 301 realizes the functions of the position information acquisition unit 32, the positional relationship acquisition unit 34, and the current estimation unit 36 by executing the bioelectric current estimation program stored in the ROM 303 or the auxiliary storage device 304. The CPU 301 may control the operation of the biomagnetic measurement system 100 such as the magnetic field measurement unit 10 and the ultrasonic measurement unit 20.

The RAM 302 is used as a work area of the CPU 301, and stores the bioelectric current estimation program and various parameters such as the Z position and the XY position. The ROM 303 stores a bioelectric current estimation program.

The auxiliary storage device 304 is a storage device such as an SSD (Solid State Drive) or an HDD (Hard Disk Drive). For example, the auxiliary storage device 304 stores a control program such as an OS (Operating System) that controls the operation of the bioelectric current estimation device 30, an ultrasonic image, morphological image data, various parameters, and the like.

The input / output interface 305 is connected to a mouse, a keyboard, and the like. The input / output interface 305 may include a communication interface for communicating with other devices. The display device 306 displays a window for displaying the current waveform shown in FIG. 5 and an operation window. The display device 306 may display the ultrasonic image shown in FIG. 3 or a diagram showing the positional relationship between the nerve and the sensor unit 14 shown in FIG.

As described above, in this embodiment, the sensor is used as compared with the case where the position of the nerve is indirectly acquired from the X-ray image by using an image (ultrasonic image or MR image) including the nerve image in which the nerve is directly captured. The position of the nerve with respect to the array 14 can be accurately obtained. For example, by using the actual XY position and Z position of the nerve acquired by using the ultrasonic image or MR image, the positional relationship between the XY position and the Z position of each sensor unit 14 can be accurately acquired. Can be done. Since the position of the nerve can be accurately acquired, for example, the intensity of the current flowing through the nerve can be correctly estimated by arithmetic processing using the spatial filter method, and the estimation accuracy of the current intensity can be improved.

When acquiring the Z position of the nerve, the XY position and Z position of the nerve and each sensor are corrected by correcting the Z position of the nerve according to the shape of the surface of the cover member 16 and the surface connecting the tips of the sensor portions 14. The positional relationship between the XY position and the Z position of the unit 14 can be accurately acquired. Therefore, the intensity of the current flowing through the nerve can be estimated more accurately, and the accuracy of estimating the current intensity can be further improved.

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 field measurement unit 12 Magnetic sensor 14 Sensor unit, sensor array 16 Cover member 20 Ultrasonic measurement unit 22 Ultrasonic probe 30 Biocurrent estimation device 32 Position information acquisition unit 34 Positional relationship acquisition unit 36 Current estimation unit 100 Biomagnetic measurement system 301 CPU
302 RAM
303 ROM
304 Auxiliary storage device 305 Input / output interface 306 Display device 307 Bus A Measurement target area MK Marker P Subject

Japanese Patent No. 4834076 Japanese Patent No. 3094988

Claims (9)

It is a bioelectric current estimation method that estimates the neural activity current generated by the neural activity of the subject based on the magnetic field data of the subject obtained by measurement with a magnetic sensor and the neural image of the subject.
Based on the nerve image included in the morphological image of the measurement target area of the subject for which the magnetic field data is measured, the position information of the nerve in the measurement target area is acquired.
Based on the acquired position information of the nerve and the position information of the magnetic sensor when facing the measurement target area, the positional relationship between the position of the nerve and the position of the magnetic sensor is acquired.
A bioelectric current estimation method characterized in that a nerve activity current is estimated based on the acquired positional relationship and the magnetic field data of the measurement target region measured by the magnetic sensor. The bioelectric current estimation method according to claim 1, wherein the position information of the nerve includes a distance in the depth direction from the surface of the measurement target region to the nerve when the magnetic sensor is opposed to the magnetic sensor. The bioelectric current estimation method according to claim 2, wherein the nerve position information includes a two-dimensional position of the nerve on the surface of the measurement target region. The bioelectric current estimation method according to any one of claims 1 to 3, wherein the position information of the magnetic sensor includes the positions of a plurality of array-shaped sensor units included in the magnetic sensor. The distance in the depth direction from the surface of the measurement target region to the nerve when the magnetic sensors are opposed to each other is the measurement target region having a shape corresponding to the curved cover member covering the tips of the plurality of sensor portions. The bioelectric current estimation method according to claim 4, wherein the method is corrected according to the above. The bioelectric current estimation method according to any one of claims 1 to 5, wherein the morphological image including the nerve image is an ultrasonic image. The bioelectric current estimation method according to any one of claims 1 to 5, wherein the morphological image including the nerve image is an MR image. A bioelectric current estimation device that estimates the neural activity current generated by the neural activity of a subject based on the magnetic field data of the subject obtained by measurement with a magnetic sensor and the neural image of the subject.
Based on the nerve image included in the morphological image of the measurement target area of the subject to measure the magnetic field data, the position information acquisition unit that acquires the position information of the nerve in the measurement target area, and the position information acquisition unit.
Based on the acquired nerve position information and the position information of the magnetic sensor when facing the measurement target area, a positional relationship acquisition unit that acquires the positional relationship between the nerve position and the magnetic sensor position. ,
A bioelectric current estimation device including a current estimation unit that estimates a neural activity current based on an acquired positional relationship and magnetic field data of the measurement target region measured by the magnetic sensor. Generated with the neural activity of the subject based on the biomagnetic measuring device having a magnetic sensor capable of measuring the magnetic field data of the subject, the magnetic field data of the subject obtained by the measurement by the magnetic sensor, and the neural image of the subject. It is a biomagnetic measurement system having a biomagnetic current estimation device that estimates the neural activity current to be performed.
The bioelectric current estimation device is
Based on the nerve image included in the morphological image of the measurement target area of the subject to measure the magnetic field data, the position information acquisition unit that acquires the position information of the nerve in the measurement target area, and the position information acquisition unit.
Based on the acquired nerve position information and the position information of the magnetic sensor when facing the measurement target area, a positional relationship acquisition unit that acquires the positional relationship between the nerve position and the magnetic sensor position. ,
A biomagnetic measurement system characterized by having a current estimation unit that estimates a neural activity current based on the acquired positional relationship and magnetic field data of the measurement target region measured by the magnetic sensor.

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