JP2970884B2 - Probe device for vascular elasticity measurement - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a blood vessel elasticity measuring probe device for measuring a blood vessel elasticity based on a time until reception of an ultrasonic wave transmitted in a radial direction of a blood vessel and a pulse pressure.

[0002]

2. Description of the Related Art Atherosclerosis progresses from young age with aging and causes various diseases up to old age. However, a quantitative diagnostic technique for the degree of arteriosclerosis has not yet been established, and the degree of progression of arteriosclerosis at an early stage has not been established. wait for the development of techniques that can be grasped
It is extremely important to develop a device that can measure the degree of arteriosclerosis with high accuracy.

[0003] The most accurate evaluation method is to evaluate the degree of arteriosclerosis based on the hardness of blood vessels, that is, the vascular elasticity, and various vascular elasticities have been proposed so far. In non-excised blood vessels in a living body, the measurement method is basically to measure the pulsatile intravascular pressure change, that is, the rate of change of the blood vessel diameter with respect to the pulse pressure. The pulsatile diameter change is reduced even by pressure, and the change in curability can be known. Among various vascular elastic moduli, the following vascular elastic moduli are frequently used to evaluate the degree of arteriosclerosis of a non-excised blood vessel. One is the pressure elastic modulus E
p, pulse pressure ΔP, blood vessel diameter D, pulsatile diameter change Δ
Let D be Ep = ΔP / (ΔD / D) (1) The pressure elasticity Ep is an elasticity that exists not only in the material hardness of the blood vessel wall but also in the thickness of the wall, and the material hardness of the blood vessel itself cannot be evaluated. To evaluate this, it is necessary to further measure the thickness of the blood vessel wall to determine the Young's modulus. If the Young's modulus is known, it is possible to clarify whether the sclerotic change due to arteriosclerosis is caused by a qualitative change or a wall thickness. Conventionally, an incremental elastic modulus has been proposed as a vascular elastic modulus that gives such a vascular wall Young's modulus. The incremental elastic modulus Einc can be obtained with good accuracy by setting the wall thickness to h, and Einc = Ep ・ (1-σ ² ) / (2h / D) ......
(2) It can be obtained by the following approximate expression. Here, σ is Poisson's ratio and the blood vessel wall is 0.5.

Conventionally, various means have been proposed for measuring the blood vessel diameter D and the pulsatile diameter change ΔD using ultrasonic waves for the purpose of obtaining the pressure elastic modulus Ep.

For example, in Japanese Patent Application Laid-Open No. 2-104340, as shown in FIGS. 12 to 14, an ultrasonic transducer 3 disposed at a symmetrical position around the distal end of an ultrasonic probe 2 inserted into a blood vessel 1 is disclosed. From the time until the ultrasonic beam is transmitted to the surrounding blood vessel wall and the reflected wave from the blood vessel inner wall and the blood vessel outer surface is received, the distance Δa, Δc between the ultrasonic transmitting / receiving means 3 and the blood vessel inner wall and the blood vessel outer surface From the distance data, the blood vessel diameter D (D = {a + {c +}}: the diameter of the ultrasonic probe), the pulsatile diameter change ΔD, and the blood vessel wall thickness h are calculated.

Further, the movement of the pressure sensor 4 provided on the distal end surface of the ultrasonic probe 2 is detected by the light guide fiber 5, and the pulse pressure ΔP is calculated based on the detected value.

[0007] Then, the above amounts are substituted into the above equations (1) and (2) to obtain a pressure elastic modulus Ep and an incremental elastic modulus Einc.
A technique for calculating a blood vessel elastic modulus from the pressure elastic modulus Ep and the incremental elastic modulus Einc, and, as shown in FIG. A technique for determining D, pulsatile diameter change ΔD, and blood vessel wall thickness h by distance measurement in four directions is disclosed.

[0008]

According to the above prior art, when the ultrasonic probe 2 is inserted into a position deviated to one side in the blood vessel 1 as shown in FIG. Even when trying to determine various quantities such as the blood vessel diameter D, accurate measurements cannot be obtained unless the ultrasonic probe 2 is inserted through the center of the blood vessel 1, and the blood vessel elastic modulus calculated based on the various quantities is not obtained. Errors also tend to occur.

The present invention has been made in view of the above circumstances, and a blood vessel capable of accurately measuring a blood vessel diameter and accurately obtaining a blood vessel elasticity regardless of an ultrasonic probe at any position in the blood vessel. An object of the present invention is to provide a probe device for measuring elastic modulus.

[0010]

According to the present invention, there is provided a probe apparatus for measuring a vascular elasticity according to the present invention, comprising: an ultrasonic transmitting / receiving means in which at least three positions around an ultrasonic probe inserted into a blood vessel are directed in different directions; Pulse pressure detecting means for detecting the pulse pressure arranged in the ultrasonic probe, using the sine law of the blood vessel diameter based on the time until receiving the reflected wave of the ultrasonic beam transmitted from each ultrasonic transmitting and receiving means A blood vessel elasticity calculating means for calculating a blood vessel elasticity based on the pulse pressure and the blood vessel diameter.

[0011]

In the above construction, when ultrasonic waves are transmitted from at least three ultrasonic transmitting / receiving means around the ultrasonic probe inserted into the blood vessel toward the wall surface of the blood vessel, the blood vessel diameter calculating means causes the ultrasonic wave to be transmitted to the blood vessel. The blood vessel diameter is calculated from the time until the reflected wave is received using the sine law.

Then, based on the pulse detected by the pulse pressure detecting means arranged on the ultrasonic probe and the blood vessel diameter, the blood vessel elasticity calculating means calculates the blood vessel elasticity.

[0013]

Embodiments of the present invention will be described below with reference to the drawings.

FIGS. 1 to 5 show a first embodiment of the present invention.
1 is a functional block diagram of a probe device for measuring the elasticity of a blood vessel, FIG. 2 is a front view showing a state in which an ultrasonic probe is inserted into a blood vessel, FIG. 3 is a configuration diagram of the probe device for measuring the elasticity of a blood vessel, and FIG . 3 is a conceptual diagram showing a calculation state of a blood vessel diameter.

(Construction) A probe device for measuring the elasticity of a blood vessel comprises an ultrasonic probe 11 and an observing device 12, and a pressure sensor comprising a diaphragm as an example of pulse pressure detecting means is provided on the distal end surface of the ultrasonic probe 11. 13 are provided.

The tip 1 of the ultrasonic probe 11
Three ultrasonic vibrators 14 as an example of ultrasonic transmitting and receiving means are provided on the outer periphery of 1a with different directing directions (θ1, θ2, θ
3) Each of the ultrasonic vibrators 1
4 is connected to the observation device 12 via a signal line 15.

Further, the movement of the pressure sensor 13 is transmitted to the observation device 12 via transmission means 16 such as a light fiber cable.

As shown in FIG. 1, the observation device 12
Transmission / reception circuit 21 connected to each ultrasonic probe 11
A blood vessel wall detecting unit 22 that receives an output of each transmitting / receiving circuit 21, a distance calculating unit 23 that receives an output of the blood vessel wall detecting unit 22, and a blood vessel diameter calculating unit that receives an output of each of the distance calculating units 23. Unit 24, a pulse pressure calculation unit 25 connected to the pressure sensor 13, the circuits 21, the calculation units 22, 23,
The blood vessel elasticity calculating unit 27 receives the output of the blood vessel diameter calculating unit 24 and a control circuit 26 for controlling the blood vessel diameter calculating unit 24.

Reference numeral 28 in FIG. 2 denotes a blood vessel wall.

(Operation) Next, the operation of the embodiment having the above configuration will be described.

An ultrasonic beam is transmitted from each ultrasonic transducer 14 to three directions of the blood vessel wall 28 by an excitation pulse output from each transmitting / receiving circuit 21 provided in the observation device 12.

Then, the blood vessel wall 2 of the ultrasonic beam
8 is received by each of the ultrasonic transducers 14,
The signal is output to the transmission / reception circuit 21 via the signal line 15.

The vascular wall detector 2 detects the vascular wall 2 based on the received waveform of the reflected wave input to the transmitting / receiving circuit 21.
8 is detected by the distance calculation unit 23, and the vascular wall 2 calculated by the vascular wall detection unit 22 after the ultrasonic wave is transmitted by the distance calculation unit 23.
8 from the surface of the ultrasonic transducer 14 to each point A,
The distance from B to C is calculated, and the length from the center 0 of the ultrasonic probe 11 to the ultrasonic transducer 14 is added to this value. Length LOA, LOB, LOC to points A, B, C
Ask for.

Thereafter, the blood vessel diameter D, the pulsatile diameter change D, and the wall thickness D of the blood vessel wall 28 are calculated by the blood vessel diameter calculating unit 24 based on the lengths L0A, L0B, and L0C using the sine law. I do.

That is, as shown in FIG. 5, since the included angles θ1, θ2, and θ3 of the respective ultrasonic transducers 14 are predetermined, the lengths AB, AB of the triangle ABC are determined according to the cosine law. BC, CA, and included angles θA, θB, θc
Then, the lengths AB, BC, CA, and the included angle θ
Based on A, θB, θc, the triangle ABC
, Ie, the diameter D of the cross section of the blood vessel is obtained from the following equation.

[0026]

This measurement is performed on the inner and outer walls of the blood vessel wall 28, and the blood vessel diameter D (inner and outer diameters), the pulsatile diameter change ΔD, and the wall thickness h of the blood vessel wall 28 are calculated.

On the other hand, the pulse pressure calculator 25
The fluctuation according to the intravascular pressure of No. 3 is input via the transmission means 16 such as a light fiber cable, and the pulse pressure ΔP is calculated from the fluctuation of the intravascular pressure.

Then, the blood vessel elasticity calculating section 27 calculates the blood vessel diameter D, the pulsatile diameter change ΔD, the wall pressure h, and the pulse pressure ΔP.
Is substituted into the above (1) and (2) to determine the pressure elasticity Ep and the incremental elasticity Einc, and the blood vessel elasticity is calculated based on the elasticities Ep and Einc.

According to this embodiment, the ultrasonic probe 11
No matter where in the blood vessel wall 28 is inserted, the blood vessel diameter D can be accurately obtained, and the accuracy of measuring the blood vessel elasticity is improved.

(Second Embodiment) FIGS. 6 to 11 show a second embodiment of the present invention, and FIG.
7 is a sectional view taken along the line VII-VII of FIG. 6, FIG. 8 is a configuration diagram of a probe device for measuring the elasticity of a blood vessel, FIG. 9 is a front view of a state in which an ultrasonic probe is inserted into a blood vessel, and FIG. FIG. 11 is a functional block diagram of a probe device, FIG. 11 is a mechanical radial scan type ultrasonic probe, (a) is a side view,
(B) is a front view, (c) is a rear view.

In this embodiment, the main body of the ultrasonic probe 31 is formed by covering a plurality of internal conductors 33 with a piezoelectric polymer 34.

That is, first, a polymer piezoelectric body 34 is arranged around a plurality of internal conductors 33 arranged at predetermined intervals, and a flake cable is connected so that the internal conductor 33 and the polymer piezoelectric body 34 are integrated. It is formed in a shape.

Next, a conductor 35 such as gold or copper is deposited on one side of one end of the polymer piezoelectric body 34 formed in a flat cable shape, and a signal line 36 is connected to the conductor 35. In addition, this end part forms an assembly part of the ultrasonic transducer 37.

Thereafter, the polymer piezoelectric body 34 is formed in a cylindrical shape so that the conductor 35 is exposed to the outside, and an internal pressure sensor 13 and a transmission means (not shown) such as a light fiber cable are provided. An ultrasonic probe 31 is formed.

After inserting the ultrasonic probe 31 into the blood vessel wall 28, three groups are selected from the plurality of internal conductors 33, and the observation device 38 is disposed between the selected internal conductor 33 and conductor 35. An excitation pulse is applied from the transmission / reception circuit 39 provided.

Then, ultrasonic waves are radiated from the piezoelectric polymer 34 sandwiched between the inner conductor 33 and the conductor 35.

Then, the reflected wave of the ultrasonic wave from the blood vessel wall 28 is received by the transmission / reception circuit 39, and the boundary detection unit 4
At 0, the boundary (inner wall or outer wall) of the blood vessel wall 28 is detected.

In the phase control unit 41, the boundary detection unit 40
The phase difference of the excitation pulse output from the transmission / reception circuit 39 to each group of the internal conductors 33 is controlled so that the ultrasonic beam is focused on the boundary detected by the above.

Then, the focus points are sequentially moved,
The tomographic image of the entire blood vessel wall is converted into an image signal by a DSC (Digital Scan Converter) 42 and then displayed on a monitor 43. When the ultrasonic probe 31 is at a position deviated from the center with respect to the blood vessel wall 28,
The phase difference between the ultrasonic transducers 37 of each group of the internal conductors 33 is controlled such that the ultrasonic beam is focused on the boundary (inner wall, outer wall), and the circumscribed circle of the triangle ABC is set as in the first embodiment. , The blood vessel elastic modulus can be measured.

According to this embodiment, since the diameter of the ultrasonic beam can be reduced, the measurement accuracy of the blood vessel elasticity can be improved.

The means for focusing the ultrasonic beam on the boundary of the blood vessel wall 28 can also be realized in the mechanical radial scan type ultrasonic probe 41 shown in FIG.

This ultrasonic probe 41 has an annular array vibrator 41b attached to the back of a vibrator (single focus) 41a for forming an entire image, and a boundary is formed from an image obtained by the single focus vibrator 41a. An annular array transducer 4 is detected to focus the ultrasonic beam on this boundary.
The tomographic image is created by controlling the phase difference 1b.

The blood vessel wall 2 detected at each certain angle
The circumscribed circle of the triangle ABC is determined from the eight boundary points A, B, and C (see FIG. 9), and the blood vessel elastic modulus is determined in the same procedure as described above.

According to the mechanical radial scan type ultrasonic probe 41, the elasticity of the blood vessel can be calculated in a short time.

[0046]

As described above, according to the present invention,
No matter where the ultrasonic probe is located in the blood vessel, excellent effects such as accurate measurement of the blood vessel diameter and accurate determination of the elasticity of the blood vessel can be obtained.

[Brief description of the drawings]

1 to 5 show a first embodiment of the present invention.
Is a functional block diagram of a probe device for measuring blood vessel elasticity

FIG. 2 is a front view showing a state where an ultrasonic probe is inserted into a blood vessel.

FIG. 3 is a configuration diagram of a probe device for measuring a blood vessel elasticity.

FIG. 4 is a left front view of FIG. 2;

FIG. 5 is a conceptual diagram showing a calculation state of a blood vessel diameter.

6 to 11 show a second embodiment of the present invention, and FIG. 6 is a development view of a main part of an ultrasonic probe.

FIG. 7 is a sectional view taken along the line VII-VII of FIG. 6;

FIG. 8 is a configuration diagram of a probe device for measuring a blood vessel elasticity.

FIG. 9 is a front view showing a state where an ultrasonic probe is inserted into a blood vessel.

FIG. 10 is a functional block diagram of a blood vessel elasticity measurement probe device.

11A is a side view, FIG. 11B is a front view, and FIG. 11C is a rear view of the mechanical radial scan type ultrasonic probe.

FIG. 12 and subsequent figures show a conventional example, and FIG. 12 is a cross-sectional view of a tip portion of an ultrasonic probe.

FIG. 13 is a perspective view of a distal end portion of the ultrasonic probe.

14 is a sectional view taken along the line XIV-XIV in FIG.

FIG. 15 is a cross-sectional view corresponding to FIG. 14 according to another embodiment.

FIG. 16 is a conceptual diagram according to a conventional example.

[Explanation of symbols]

 11, 31, 41 ... ultrasonic probe 13 ... pulse pressure detecting means 14, 37, 41A, 41b ... ultrasonic transmitting and receiving means 24 ... blood vessel diameter calculating means 27 ... blood vessel elasticity calculating means 28 ... blood vessel wall D ... blood vessel diameter ΔP ... Pulse pressure

Claims (1)

(57) [Claims] 1. An ultrasonic transmitting / receiving means in which at least three points around an ultrasonic probe to be inserted into a blood vessel are directed in different directions, and a pulse pressure detecting means arranged on the ultrasonic probe to detect a pulse pressure. A blood vessel diameter calculating means for calculating the blood vessel diameter using a sine law based on the time until the reflected wave of the ultrasonic beam transmitted from each ultrasonic transmitting and receiving means is received, and the pulse pressure and the blood vessel diameter A blood vessel elastic modulus calculating means for calculating a blood vessel elastic modulus based on the blood vessel elastic modulus.