JPH10328152A - Electromagnetic rheometer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily and exactly measure blood stream speed without largely burdening an examinee. SOLUTION: A main body 2 of measuring part is arranged on the body surface of examinee a while being pressed, and the blood vessel to be measured near the body surface of the examinee is put into a measuring groove 6 provided on an examinee abutting face 2a on the main body 2 of measuring part. Then, magnetic flux C for measurement is generated from a blood stream detection part 3 along with the almost perpendicular direction of the inner surface of measuring groove 6 and by detecting the fluctuation of magnetic flux C for measurement caused by the circulation of blood flowing in the measuring groove 6, the blood stream speed is detected.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic blood flow meter used for measuring a blood flow of a specimen at a medical site or the like.

[0002]

2. Description of the Related Art Conventionally, there is an electromagnetic blood flow meter as a blood flow meter capable of quantitatively measuring a blood flow. The electromagnetic blood flow meter generates a measurement magnetic flux that penetrates the blood vessel to be measured, and measures the blood flow by detecting fluctuations in the measurement magnetic flux caused by the blood flow. It is possible to accurately and quantitatively measure the blood flow by measuring the subtle magnetic flux fluctuation that occurs.

[0003]

However, in the conventional electromagnetic blood flow meter, the blood flow must be measured after the body surface of the sample (patient) is incised and the blood vessel to be measured is removed from the sample. During the measurement, a painful operation is required for the sample (patient), which places a heavy burden on the sample, and there is a problem that the measurement cannot be performed unnecessarily. This is based on the following reasons.

A magnetic flux generating coil constituting a conventional electromagnetic blood flow meter is formed by manually winding a steel wire or the like around a magnetic core, and it is difficult to reduce the size in terms of structure. For this reason, the electromagnetic blood flow meter including the magnetic flux generating coil having such a configuration cannot be easily carried by a measurer and can be measured only in a state close to stationary.

In order to measure the blood flow using an electromagnetic blood flow meter having such a limitation at the time of measurement, it is necessary to carry a blood vessel to be measured into the electromagnetic blood flow meter.
The body surface had to be incised and the blood vessel to be measured had to be removed from the specimen.

The present invention has been made in view of the above-described problems, and enables easy measurement without imposing a large burden on a sample such as incising a body surface of the sample (patient) and removing a blood vessel to be measured from the sample. The challenge is to do.

[0007]

The applicant of the present invention has proposed a thin-film flux gate magnetic sensor suitable for constituting a blood flow detecting section of such an electromagnetic blood flow meter in Japanese Patent Application Laid-Open No. 8-201061 or the like. doing. The present invention solves the above-mentioned problem by using such a thin-film fluxgate magnetic sensor and further improving it to constitute an electromagnetic blood flow meter.

That is, according to the present invention, there is provided a measuring section main body having a measurement groove which is pressed against a body surface of a sample, and has a measurement groove on its sample contact surface into which a blood vessel to be measured near the surface of the sample body is pressed by the sample. An electromagnetic blood flow meter comprising a blood flow detector that generates a magnetic flux for measurement along a direction substantially perpendicular to the inner surface of the measurement groove and detects a change in the magnetic flux for measurement caused by a blood flow flowing in the measurement groove. Thus, the above-described problem is solved.

[0009] The blood flow detector is formed of first and second excitation coil patterns, which are formed in reverse winding patterns to generate a measurement magnetic flux along a direction substantially perpendicular to the inner surface of the measurement groove, and a measurement magnetic flux. It is preferable that a receiving coil pattern for generating an induced voltage signal due to the fluctuation of the above and a high magnetic permeability thin film pattern serving as a magnetic core of these coil patterns are formed on a substrate.

[0010]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a side view showing a state in which an electromagnetic blood flow meter 1 according to an embodiment of the present invention is mounted on a sample α, and FIG. 2 is a blood flow detecting unit 3 constituting the electromagnetic blood flow meter 1.
FIG. 3 is a block diagram showing a circuit configuration of the electromagnetic blood flow meter 1.

The electromagnetic blood flow meter 1 drives the measurement unit main body 2 pressed against the body surface of the sample α, the blood flow detection unit 3 provided on the measurement unit main body 2, and the blood flow detection unit 3. And a fastening band 5 for fastening the measurement unit body 2 to the body surface of the specimen α.

The measuring section main body 2 is a detection site (arm, etc.) of the sample α.
It is formed of a substantially rectangular parallelepiped box having a size that can be mounted on the box. A measurement groove 6 is formed at the center in the width direction of the sample contact surface 2a of the measurement section main body 2. The measurement groove 6 is formed over both ends of the sample contact surface 2a, and both ends of the groove are open. The inner width of the measurement groove 6 is slightly larger than the diameter of the measurement target blood vessel β near the body surface of the specimen α. The corner 7 where the sample contact surface 2a and the measurement groove 6 are in contact slightly protrudes outward, and the tip of the protruding corner 7 is provided with a radius to reduce hit (physical impact) to the sample α. ing.

The blood flow detecting section 3 is composed of a thin-plate flux gate magnetic sensor, and is attached to one of the inner surfaces of the measurement groove 6 facing each other. The blood flow detector 3 includes a substrate 8 such as a glass substrate, as shown in FIG. On the substrate 8, a pair of high-permeability material thin film patterns 9A and 9B each having a rectangular pattern and each serving as a magnetic core (core) of the coil pattern are formed with a slight gap therebetween. As a material forming the high magnetic permeability material thin film patterns 9A and 9B, for example, perma carp can be used.

Exciting coil patterns 10A and 10B having spiral patterns of opposite winding are formed on the substrate 8 so as to surround the high-permeability forestry thin film patterns 9A and 9B. The excitation coil patterns 10A and 10B are made of a low-resistance material such as copper (Cu).

On the substrate 8, each excitation coil pattern 10
A receiving coil pattern 11 made of a thin film wiring of a low-resistance material such as copper (CU) is formed so as to surround A and 10B.

Each of these coil patterns 9A, 9B, 1
1, both ends of the receiving coil pattern 11 are guided to pads (not shown) provided on the substrate 8, and the excitation coil patterns 10A and 10B are formed by a continuous pattern. Are also led to pads (not shown) provided separately on the substrate 8.

Here, each of the coil patterns 10A, 10A
In the pattern including the lead lines of B and 11, the pattern areas intersecting in the plan view are insulated and separated from each other by interposing an insulating film such as SiO ₂ between the coil patterns 10A, 10B and 11. I have.

The blood flow detector 3 configured as described above measures the blood flow as follows. That is, by passing an alternating current through the excitation coil patterns 10A and 10B, magnetic fields of opposite directions act along the thickness direction of the substrate 8,
Further, measurement magnetic fluxes in mutually opposite directions are generated inside the high magnetic permeability thin film patterns 9A and 9B along the thickness direction. Then, electromotive force is generated in the receiving coil pattern 11 by the measurement magnetic fluxes generated in the opposite directions.

Here, the excitation coil patterns 10A, 10A
B, the amount of alternating current flowing through B is reduced to high magnetic permeability thin film patterns 9A and 9B.
Is sufficient to magnetically saturate, the electromotive force becomes a value proportional to the external magnetic field in the thickness direction of the high magnetic permeability thin film patterns 9A and 9B, that is, in the direction orthogonal to the substrate 8. . Therefore, when the blood vessel β to be measured is arranged so that the blood flow comes in a direction parallel to the plane direction of the substrate 8 (a direction orthogonal to the measurement magnetic flux formed in the opposite direction to each other), the measurement magnetic flux is caused by the blood flow. And the electromotive force generated in the receiving coil pattern 11 also changes. Therefore, by examining the change in the electromotive force, the flow velocity of the blood flow can be accurately detected. Specifically, the detection coil pattern 11
Can be calculated by the following equation.

E = Bdv ... e: electromotive force B: magnetic flux density of measurement magnetic flux generated in the high magnetic permeability thin film patterns 9A, 9B d: diameter of blood vessel β to be measured v: average flow velocity of blood flow signal processing section 4 Is incorporated in the measuring section main body 2,
As shown in the block diagram of FIG.
Exciter 1 that supplies AC current g for excitation to 0A and 10B
2 and the electromotive force signal e generated in the receiving coil pattern 11
, A synchronous detector 14 that extracts only a signal component from the electromotive force signal e ′ amplified by the signal amplifier 13, and a low-pass filter 15 that removes a high-frequency noise component from the electromotive force signal e ′. Have been.

Hereinafter, the operation of measuring the blood flow using the electromagnetic blood flow meter 1 will be described. First, the supply amount of the alternating current g is adjusted in advance so that the high magnetic permeability thin film patterns 9A and 9B are sufficient to magnetically saturate. After such initial settings, first, the measurement unit main body 2 is applied to the measurement site (arm, etc.) of the sample (patient) α. At this time, the measurement unit main body 2 is arranged so that the measurement groove 6 is located along the blood vessel β at a position above the measurement target blood vessel β near the body surface of the measurement site. After the measurement unit main body 2 is arranged at the measurement site in this manner, the fastening band 5 is fastened to the sample α to fix the measurement unit main body 2 to a certain extent by pressing the measurement unit main body 2 against the measurement site.

Then, the sample contacting surface 2a of the measuring section main body 2 is disposed in a state of being depressed on the body surface of the sample α, and the corners 7 of the measuring section main body 2 sandwich the body blood vessel β to be measured. Into the measuring groove 6 (see FIG. 1). At this time, since the corner 7 is rounded, even if the corner 7 bites into the surface of the sample body, the sample (patient) hardly feels pain.

In this state, the electromagnetic blood flow meter 1 is driven. That is, the excitation coil patterns 10A, 10A
B is supplied with an AC current g for excitation. Then, mutually opposite magnetic fields act along the thickness direction of the substrate 8, and further, measurement magnetic fluxes C mutually opposite along the thickness direction are generated inside the high permeability thin film patterns 9 </ b> A and 9 </ b> B. I do. Since the blood flow detector 3 is disposed along the inner surface of the measurement groove 6, the generated measurement magnetic flux C moves the measurement target blood vessel β in the radial direction substantially along a perpendicular line of the inner surface of the measurement groove 6. Is formed in a shape penetrating through.

Here, the supply amount of the alternating current g is adjusted in advance so that the high magnetic permeability thin film patterns 9A and 9B are sufficient to be magnetically saturated. Therefore, the measurement magnetic flux C fluctuates in proportion to the blood flow velocity of the measurement target blood vessel β flowing in the measurement groove 6, and the receiving coil pattern 11 receives the electromotive force signal e proportional to the fluctuation of the measurement magnetic flux C. Occur.

The electromotive force signal e generated in the receiving coil pattern 11 is input to the signal processing unit 4. In the signal processing unit 4, after the input electromotive force signal e is amplified by the signal amplifier 12, synchronous detection is performed by the synchronous detector 14, and only the signal component is extracted from the amplified electromotive force signal e '. After the high frequency noise component is removed by the filter 15, the signal is output to the outside of the signal processing unit 4. Since the output signal E output from the signal processing unit 4 changes in proportion to the blood flow velocity in this manner, the signal level of the output signal E is detected by a detector (not shown), Measurement magnetic flux C generated in magnetic susceptibility thin film patterns 9A and 9B
By substituting the magnetic flux density B and the diameter d of the measurement target blood vessel β into the following expression that is a modification of the above expression, the average flow velocity v of the blood flow in the measurement target blood vessel β can be accurately measured.

V = E / Bd As described above, in the electromagnetic blood flow meter 1, a large burden is imposed on the specimen α such that the body surface of the specimen (patient) α is incised and the blood vessel β to be measured is removed from the specimen α. The blood flow velocity of the blood vessel β to be measured can be accurately measured only by pressing and placing the measurement unit main body 2 on the body surface of the specimen α without forcing.

By the way, in the above-described electromagnetic blood flow meter 1, as shown in FIG. 2, the blood flow detecting unit 3 surrounds a pair of high magnetic permeability thin film patterns 9A and 9B which are arranged adjacent to each other to form an excitation coil pattern. 10A and 10B, and the receiving coil pattern 11 is formed so as to surround the exciting coil patterns 10A and 10B. However, the blood flow detection unit of the present invention is not limited to such a configuration, and the blood flow detection unit 20 may include a ring-shaped high magnetic permeability thin film pattern 21 as shown in FIG.

In the blood flow detecting section 20, a ring-shaped high magnetic permeability thin film pattern 21, an excitation coil pattern 22 wound therearound, and receiving coil patterns 23A, 23
B is formed on the substrate 24 by patterning.
The excitation coil patterns 22 of the blood flow detection unit 20 are all wound in the same direction, and the reception coil patterns 23A and 23B are differential coils, that is,
The high-permeability thin-film pattern 21 is divided into left and right halves in FIG. 4, each of which is wound in the opposite direction, and is formed of a pair of coil patterns connected in series with each other.

In the blood flow detector 20 configured as described above, the measurement magnetic flux C 'is generated along the plane direction of the substrate 24 (the left-right direction in the figure). Therefore, when the blood flow detecting unit 20 is incorporated into the measuring unit main body 2, the substrate 24 is perpendicular to the inner surface of the measuring groove 6 in order to generate the measurement magnetic flux C ′ along the perpendicular direction of the inner surface of the measuring groove 6. It is necessary to arrange the blood flow detection unit 20 in the measurement unit main body 2 so as to be parallel to the direction.

In the above-described electromagnetic blood flow meter 1, the signal processing unit 4 is incorporated in the measuring unit main body 2, but the signal processing unit 4 is connected to the blood flow detecting unit 3 while the measuring unit It may be arranged outside the main body 2.

[0031]

As described above, according to the present invention, a large burden is not imposed on a sample such as incising the body surface of a sample (patient) and removing a blood vessel to be measured from the sample.
The blood flow velocity of the blood vessel to be measured can be accurately measured only by pressing the measurement unit main body against the body surface of the sample, and the blood flow measurement is simplified as compared with the related art.

[Brief description of the drawings]

FIG. 1 is a side view showing a state in which an electromagnetic blood flow meter according to an embodiment of the present invention is mounted on a sample.

FIG. 2 is a plan view illustrating a configuration of a blood flow detection unit included in the electromagnetic blood flow meter according to the embodiment;

FIG. 3 is a block diagram illustrating a circuit configuration of the electromagnetic blood flow meter according to the embodiment;

FIG. 4 is a plan view showing a modification of the blood flow detection unit.

[Explanation of symbols]

2 Measurement unit main body 2a Sample contact surface 3 Blood flow detection unit 4 Signal processing unit 6 Measurement groove 8 Substrate 9A, 9B High permeability thin film pattern 10A, 10B Excitation coil pattern 11
Receiving coil pattern 20 Blood flow detecting unit 21 High magnetic permeability thin film pattern 22 Exciting coil pattern 23A, 23B Receiving coil pattern α Sample β Target blood vessel C Measurement magnetic flux e Electromotive force

Claims (2)

[Claims] 1. A measuring unit main body having a measurement groove which is pressed against a body surface of a sample and has a sample contact surface on a sample contact surface thereof, into which a blood vessel to be measured near the surface of the sample body enters by pressing against the sample, and an inner surface of the measurement groove. And a blood flow detecting unit for generating a measurement magnetic flux along a substantially perpendicular direction of the blood flow and detecting a fluctuation of the measurement magnetic flux caused by a blood flow flowing in the measurement groove. 2. The electromagnetic blood flow meter according to claim 1, wherein the blood flow detectors are formed in reverse winding patterns to generate a magnetic flux for measurement along a direction substantially perpendicular to the inner surface of the measurement groove. A first excitation coil pattern, a reception coil pattern for generating an induced voltage signal due to a change in measurement magnetic flux, and a high magnetic permeability thin film pattern serving as a magnetic core of these coil patterns are formed on a substrate. An electromagnetic blood flow meter, characterized in that: