JP2024174455A - Ultrasonic measurement device, ultrasonic measurement method - Google Patents

Abstract

To perform accurate measurement by suppressing an influence by a movement of a measurement object.SOLUTION: An ultrasonic measuring apparatus includes an ultrasonic radiation detection unit having a radiation detection surface for sending an ultrasonic wave toward a measurement object having a boundary surface in which differences in acoustic impedance exist, and receiving a perpendicular reflection wave which is generated when the ultrasonic wave sent toward the measurement object is perpendicularly reflected on the boundary surface. The ultrasonic radiation detection unit sends the ultrasonic wave radially.SELECTED DRAWING: Figure 1

Description

The present invention relates to an ultrasonic measurement device and an ultrasonic measurement method.

As a method for non-invasively measuring a subject's blood pressure, a technology is known in which the diameter of the subject's blood vessels is measured using ultrasound and the blood pressure is estimated from the diameter of the blood vessels. For example, Patent Document 1 describes an example in which two ultrasound probes are used. Patent Document 2 describes an example in which a two-dimensional array ultrasound unit having multiple ultrasound elements 11 arranged in an array is used. The inventor of the present application has also already filed Patent Document 3.

Patent No. 6692026 JP 2018-102589 A JP 2020-089605 A

Originally, there was a problem with measuring blood vessel diameter using ultrasound because the effect of the subject's body movement could not be ignored, making it difficult to perform accurate measurements. In other words, body movement makes it difficult to perform stable measurements, and the lack of robustness against body movement was the biggest factor preventing the sensor from being put to practical use.
In response to this, conventional techniques have had problems in that the configuration is complicated and the number of parts is large, resulting in an increase in the size of the device and in the manufacturing costs.

Furthermore, given the recent trend towards health consciousness, there is a demand for ultrasonic measuring devices that can be worn at all times.

The present invention has been made in consideration of the above circumstances, and aims to achieve the following objects.
1. To enable accurate ultrasonic measurement with a simple configuration.
2. To enable ultrasonic measurement by suppressing the effects of the subject's body movements.
3. To achieve compactness with a simple configuration.
4. It must be possible to wear it at all times.

The inventors of the present application investigated the state in which blood vessel diameter cannot be accurately measured using ultrasound as follows, and hypothesized the reason for this.

When measuring blood vessel diameter using ultrasound, ultrasound is sent from the surface of the subject's body toward the depths of the body, and the reflected waves from the blood vessel walls inside the body are obtained, and the arrival time difference between the reflected waves from the blood vessel walls on the surface of the body and those deep inside the body is measured.

Based on the difference in arrival time of the reflected waves, the difference between the distance to the blood vessel wall on the body surface side and the distance to the blood vessel wall on the deep body side is obtained to calculate the blood vessel diameter value.
Piezoelectric elements are used to emit and irradiate ultrasonic waves and to detect reflected waves. In this case, the surface of the element that emits ultrasonic waves and the surface of the element that receives reflected waves are the same emission and detection surface.

When the detection signal of the reflected wave becomes small, the S/N ratio becomes small and the signal becomes buried in noise. This makes it impossible to accurately measure the arrival time difference, and as a result, it becomes impossible to accurately calculate the blood vessel diameter.

One of the factors that can reduce the reflected wave is a change in the positional relationship between the detection part and blood vessels due to bodily movements of the subject.
When the radiation detection surface that transmits ultrasonic waves and receives reflected waves is parallel to the blood vessel wall that reflects the ultrasonic waves, the perpendicular reflected wave that is perpendicularly reflected from the blood vessel wall to be measured is reflected toward the detection surface. The perpendicular reflected wave is incident on the radiation detection surface with sufficient strength, so that a detection signal with sufficient strength can be obtained.
Furthermore, there is no deviation in the timing of receiving the reflected wave.

On the other hand, if the blood vessel wall that reflects the ultrasound is not parallel to the radiation detection surface, the reflected wave may not reach the radiation detection surface. This means that the reflected wave cannot be received. Even if the reflected wave can be received, the distance traveled by the reflected wave from the blood vessel wall to return to the radiation detection surface varies, resulting in a difference in the timing at which the reflected wave is received.

In other words, if the distance the reflected wave travels from the blood vessel wall to the radiation detection surface varies, the timing of reception will differ, causing the reflected wave to be added together and reducing its strength. This is thought to be causing a problem in which the reflected wave cannot be received at the radiation detection surface with sufficient strength.

Here, we consider the change in position between the radiation detection surface and the blood vessel wall due to body movement.

First, a case will be considered in which the radiation detection surface moves along the epidermis in the radial direction of the blood vessel to be measured while maintaining the parallel state between the radiation detection surface and the blood vessel wall.
When the radiation detection surface moves along the epidermis in the radial direction of the blood vessel to be measured, the cross section of the blood vessel has a circular shape. Therefore, there is a portion parallel to the radiation detection surface, and the reflected wave that passes near the center position that can be regarded as the axis of the blood vessel and returns to the radiation detection surface, i.e., the vertical reflected wave, can maintain an intensity sufficient to output a detection signal.

Next, a case will be considered in which the position of the radiation detection surface with respect to the epidermis does not change, but the radiation detection surface is inclined in the radial direction of the blood vessel to be measured.
In this case, as in the case described above, even if the position of the radiation detection surface with respect to the epidermis does not change and the radiation detection surface is inclined in the radial direction of the blood vessel to be measured, there is a portion parallel to the radiation detection surface because the cross section of the blood vessel has a circular, round shape. Although the reflected wave that passes near the center position that can be regarded as the axis of the blood vessel and returns to the radiation detection surface, that is, the vertical reflected wave, decreases, it is possible to maintain an intensity sufficient to output a detection signal.
Therefore, it is possible to detect vertical reflected waves due to radial position changes of blood vessels caused by body movement, and it is considered that this does not contribute much to inaccuracies in blood vessel diameter.

In contrast, when the radiation detection surface is maintained parallel to the blood vessel wall and the radiation detection surface is moved along the epidermis in the axial direction of the blood vessel being measured, the reflected wave that passes near the axis of the blood vessel and returns to the radiation detection surface can maintain an intensity sufficient to output a detection signal.
However, in many cases, the body surface and the axis of the blood vessel do not maintain a parallel positional relationship. In other words, when the radiation detection surface moves along the epidermis in the axial direction of the blood vessel to be measured, the radiation detection surface and the blood vessel wall will be inclined in the axial direction of the blood vessel.
Here, the axial direction of a blood vessel generally means the direction along the blood flow.

Next, a case will be considered in which the position of the radiation detection surface with respect to the epidermis does not change, but the radiation detection surface is tilted in the axial direction of the blood vessel to be measured.
Since blood vessels do not have a circular shape in the axial direction, the blood vessel walls that reflect ultrasonic waves are not parallel to the radiation detection surface, and there is no vertically reflected wave that passes near the axis of the blood vessel and returns to the radiation detection surface. In other words, the radiation detection surface cannot receive the vertically reflected wave.
Alternatively, if the radiation detection surface is inclined in the axial direction of the blood vessel being measured, the blood vessel wall that reflects the ultrasound will not be in a parallel position to the radiation detection surface, and the reflected wave received by the radiation detection surface will be out of phase, resulting in an inaccurate measurement.

In consideration of this situation, the inventors of the present application provide an ultrasonic measurement device and ultrasonic measurement method that can selectively receive vertically reflected waves in response to a state in which the radiation detection surface is inclined in the axial direction of the blood vessel being measured, thereby enabling accurate measurements.

(1) An ultrasonic measurement device according to one aspect of the present invention,
an ultrasonic radiation detection unit having a radiation detection surface that transmits ultrasonic waves toward a measurement target having an interface inside which an acoustic impedance difference exists, and receives vertically reflected waves of the ultrasonic waves transmitted to the measurement target and vertically reflected at the interface;
The ultrasonic radiation detection unit radially transmits the ultrasonic wave.
It is characterized by:
(2) The ultrasonic measuring device of the present invention, in the above (1),
the interface is generally cylindrical;
the radiation detection surface is curved in a direction at least along an axis of the interface;
It is possible.
(3) The ultrasonic measuring device of the present invention is the above-mentioned (2),
The ultrasonic radiation detection unit has a radiation detection surface having a curved surface shape that is a part of a cylindrical surface.
It is possible.
(4) The ultrasonic measuring device of the present invention, in the above (2),
The ultrasonic radiation detection unit has a radiation detection surface having a curved shape that is a part of a sphere.
It is possible.
(5) The ultrasonic measuring device of the present invention, in the above (1),
The ultrasonic radiation detection unit includes an element unit that transmits and receives the ultrasonic waves,
an acoustic lens unit that transmits the radial ultrasonic wave toward the interface and transmits the received vertical reflected wave to the element unit;
having
It is possible.
(6) The ultrasonic measuring device of the present invention is the above (5),
the interface is generally cylindrical;
the acoustic lens portion has the radiation detection surface,
the radiation detection surface is curved in a direction at least along an axis of the interface;
It is possible.
(7) The ultrasonic measuring device of the present invention is the above (6),
The radiation detection surface is a curved surface that is a part of a cylindrical surface.
It is possible.
(8) The ultrasonic measuring device of the present invention is the above-mentioned (6),
The radiation detection surface has a curved shape that is a part of a sphere.
It is possible.
(9) The ultrasonic measuring device of the present invention is the above-mentioned (5),
The element portion has a planar radiation detection element surface,
The acoustic lens portion is in contact with the radiation detection element surface.
It is possible.
(10) The ultrasonic measuring device of the present invention is the above-mentioned (5),
The element portion is composed of a single element.
It is possible.
(11) The ultrasonic measuring device of the present invention is the above-mentioned (5),
the acoustic impedance of the element portion is greater than the acoustic impedance of the acoustic lens portion,
The acoustic impedance of the acoustic lens portion is greater than the acoustic impedance of the measurement object located on both sides of the interface.
It can be said that.
(12) The ultrasonic measuring device of the present invention, in the above (1),
The ultrasonic radiation detection unit has a plurality of element units that transmit and receive the ultrasonic waves.
It is possible.
(13) An ultrasonic measurement method according to another aspect of the present invention includes:
The ultrasonic radiation detection unit transmits ultrasonic waves to a measurement target having an interface having an internal acoustic impedance difference, and receives a vertically reflected wave of the transmitted ultrasonic waves perpendicularly reflected at the interface to determine a distance from the ultrasonic radiation detection unit to the interface.
The ultrasonic radiation detection unit radially transmits the ultrasonic wave.
It is possible.
(14) An ultrasonic measurement method according to another aspect of the present invention includes:
the interface is generally cylindrical;
The ultrasonic wave is transmitted radially in at least a direction along an axis of the interface.
It is possible.
(15) Another aspect of the present invention provides an ultrasonic measurement method according to the above (14), comprising:
The ultrasonic radiation detection unit receives the vertical reflected wave on a radiation detection surface,
determining a distance from the radiation detection surface to the interface;
It is possible.
(16) Another aspect of the present invention provides an ultrasonic measurement method according to the above (15), comprising:
determining a diameter of the interface based on a difference between a distance from the radiation detection surface to the interface on a surface side of the cylindrical interface and a distance from the radiation detection surface to the interface on a deeper side of the cylindrical interface, based on a difference in arrival times of the perpendicular reflected waves to the radiation detection surface;
It is possible.
(17) Another aspect of the present invention provides an ultrasonic measurement method according to the above (15), comprising:
The ultrasonic radiation detection unit includes an element unit that transmits and receives ultrasonic waves,
an acoustic lens unit that transmits the radial ultrasonic wave toward the interface and transmits the received vertical reflected wave to the element unit;
having
the acoustic impedance of the element portion is greater than the acoustic impedance of the acoustic lens portion,
The acoustic impedance of the acoustic lens portion is greater than the acoustic impedance of the measurement object located on both sides of the interface.
It can be said that.
(18) Another aspect of the present invention provides an ultrasonic measurement method according to the above (17), comprising:
The ultrasonic wave is emitted from the radiation detection surface in a radially expanding manner in a curved surface shape that is a part of a cylindrical surface.
It is possible.
(19) Another aspect of the present invention provides an ultrasonic measurement method according to the above (17), comprising:
The ultrasonic wave is transmitted from the radiation detection surface in a radially expanding manner in a curved surface shape that is a part of a sphere.
It is possible.

The ultrasonic measurement device of the present invention has the above-mentioned configuration (1), and can accurately measure the distance to the interface using the vertical reflected wave reflected at the interface. In this case, by sending out ultrasonic waves radially, the vertical reflected wave can be accurately received even if the ultrasonic emission detection unit is tilted with respect to the interface. This improves the accuracy of the distance measurement to the interface. Since there is no need to control multiple element units simultaneously, it is possible to measure the shape of the interface with a simple configuration.

The ultrasonic measurement device of the present invention has the above-mentioned configuration (2), and emits radial ultrasonic waves that spread in a direction along the axis of the interface. This allows accurate reception of vertically reflected waves even when the ultrasonic emission detection unit is tilted in the axial direction of the interface. This improves the accuracy of distance measurement to a cylindrical interface. By measuring the distance to the interface on the surface side and the deep side of a cylindrical interface, it becomes possible to easily and accurately measure the diameter dimension of the cylindrical interface.

The ultrasonic measurement device of the present invention has the above-mentioned configuration (3), and emits radial ultrasonic waves that spread in a direction along the axis of the interface. This makes it easy to accurately measure the diameter of a cylindrical interface by measuring the distance from the surface side to the deep side of the interface, even if the ultrasonic radiation detection unit is tilted in the axial direction of the interface.

The ultrasonic measurement device of the present invention has the above-mentioned (4) configuration, and emits radial ultrasonic waves that spread out spherically, regardless of the axis of the interface. As a result, even if the ultrasonic radiation detection unit is tilted, it is possible to easily and accurately measure the diameter of the cylindrical interface by measuring the distance from the surface side to the deep side of the interface, regardless of the direction in which the ultrasonic radiation detection unit is tilted.

The ultrasonic measurement device of the present invention has the above-mentioned configuration (5), and thus the ultrasonic waves sent from the element unit are expanded by the acoustic lens unit and sent to the measurement object, and the vertically reflected waves reflected from the interface are received and returned to the element unit by the acoustic lens unit without phase difference. As a result, even if the ultrasonic emission detection unit is tilted with respect to the interface, the vertically reflected waves can be accurately received. This improves the accuracy of distance measurement to the interface.

The ultrasonic measurement device of the present invention has the configuration (6) above, and thus can use the acoustic lens unit to expand and transmit ultrasonic waves from the radiation detection surface in a direction along the axis of the cylindrical interface being measured, and can receive vertically reflected waves reflected from the interface by the radiation detection surface and return them to the element unit without phase difference. This allows the vertically reflected waves to be received accurately even if the ultrasonic radiation detection unit is tilted relative to the interface. This can improve the accuracy of distance measurement to the interface.

The ultrasonic measurement device of the present invention has the above configuration (7), and emits radial ultrasonic waves that spread in a direction along the axis of the cylindrical surface of the radiation detection surface. As a result, even if the ultrasonic radiation detection unit is tilted, the ultrasonic waves can be spread from the radiation detection surface by the acoustic lens unit in the direction along the axis and sent to the measurement object, and the vertical reflected waves reflected from the interface can be received by the radiation detection surface and returned to the element unit without phase difference. As a result, even if the ultrasonic radiation detection unit is tilted with respect to the interface, the vertical reflected waves can be accurately received. The accuracy of measuring the distance to the interface can be improved.

The ultrasonic measurement device of the present invention has the above-mentioned configuration (8), and emits radial ultrasonic waves from the radiation detection surface so as to spread in the entire circumferential direction of the radiation detection surface. As a result, even if the ultrasonic radiation detection unit is tilted, the acoustic lens unit can spread the ultrasonic waves from the radiation detection surface and send them to the measurement object, regardless of the direction in which the ultrasonic radiation detection unit is tilted, and the vertical reflected waves reflected from the interface can be received by the radiation detection surface and returned to the element unit without phase difference. As a result, even if the ultrasonic radiation detection unit is tilted with respect to the interface, the vertical reflected waves can be accurately received. The accuracy of measuring the distance to the interface can be improved.

The ultrasonic measurement device of the present invention has the configuration of (9) above, and transmits ultrasonic waves from the radiation detection element surface, and then expands the ultrasonic waves by the acoustic lens unit and transmits them to the measurement object. In addition, ultrasonic waves reflected from the interface of the measurement object are received by the acoustic lens unit, and then the ultrasonic waves are returned to the radiation detection element surface by the acoustic lens unit and received there. This makes it possible to accurately receive vertically reflected waves even if the ultrasonic radiation detection unit is tilted with respect to the interface. This makes it possible to improve the accuracy of distance measurement to the interface.

The ultrasonic measurement device of the present invention has the above-mentioned configuration (10), and therefore does not need to simultaneously control multiple element units, making it possible to measure the shape of the interface with a simple configuration. The accuracy of measuring the distance to the interface can be improved.

The ultrasonic measurement device of the present invention has the above-mentioned configuration (11), which can improve the accuracy of the measurement of the shape of the interface.

The ultrasonic measurement device of the present invention has the above-mentioned configuration (12), and is therefore capable of sending out radial ultrasonic waves toward the interface and receiving vertically reflected waves at the element section. This allows accurate reception of vertically reflected waves even when the ultrasonic emission detection section is tilted relative to the interface. This improves the accuracy of distance measurement to the interface.

The ultrasonic measurement method of the present invention has the above-mentioned configuration (13), so that even if the ultrasonic radiation detection unit is tilted with respect to the interface, ultrasonic waves can be emitted radially and vertically reflected waves can be accurately received. This improves the accuracy of measuring the distance to the interface.

The ultrasonic measurement method of the present invention has the above-mentioned configuration (14), and emits radial ultrasonic waves that spread in a direction along the axis of the cylindrical shape. This allows accurate reception of vertically reflected waves even when the ultrasonic radiation detection unit is tilted in the axial direction of the interface. This improves the accuracy of distance measurement to a cylindrical interface. By measuring the distance to the interface on the surface side and the deep side of a cylindrical interface, it becomes possible to easily and accurately measure the diameter dimension of the cylindrical interface.

The ultrasonic measurement method of the present invention has the above-mentioned configuration (15), and by receiving ultrasonic waves at the radiation detection surface, it is possible to improve the reception accuracy of vertically reflected waves that are reflected vertically at an interface among the reflected waves of the radially transmitted ultrasonic waves. This makes it possible to improve the accuracy of measuring the distance to the interface.

The ultrasonic measurement method of the present invention has the above-mentioned configuration (16), so that it is easy to accurately measure the diameter of a cylindrical interface even when the ultrasonic radiation detection unit is tilted with respect to the interface.

The ultrasonic measurement method of the present invention has the above-mentioned configuration (17), which can improve the accuracy of the interface shape measurement.

The ultrasonic measurement method of the present invention has the above-mentioned configuration (18), and emits radial ultrasonic waves that spread in a direction along the axis of the interface. This makes it easy to accurately measure the diameter of a cylindrical interface by measuring the distance from the surface side to the deep side of the interface, even if the ultrasonic radiation detection unit is tilted in the axial direction of the interface.

The ultrasonic measurement method of the present invention has the above-mentioned (19) configuration, and emits radial ultrasonic waves that spread spherically regardless of the axis of the interface. As a result, even if the ultrasonic radiation detection unit is tilted, it is possible to easily and accurately measure the diameter of the cylindrical interface by measuring the distance from the surface side to the deep side of the interface, regardless of the direction in which the ultrasonic radiation detection unit is tilted.

The present invention has the following advantages: it is possible to provide an ultrasonic measurement device and an ultrasonic measurement method that can accurately measure blood vessel diameter with a simple configuration, can measure blood vessel diameter while suppressing the effects of the subject's body movements, can be made compact with a simple configuration, and can be worn at all times.

1 is a schematic diagram showing a first embodiment of an ultrasonic measurement device and an ultrasonic measurement method according to the present invention; 4 is a graph illustrating the time variation of measurement data of a reflected wave in a first embodiment of an ultrasonic measurement device and an ultrasonic measurement method according to the present invention. 4 is a graph illustrating the relationship between blood vessel diameter and time measured in the first embodiment of the ultrasonic measurement device and ultrasonic measurement method according to the present invention. FIG. 13 is a diagram illustrating a cross section in the radial direction of a blood vessel, illustrating a reflected wave when the measurement surface of the blood vessel diameter measurement device is positioned parallel to the blood vessel wall. FIG. 13 is a diagram illustrating a cross section of a blood vessel in the axial direction, illustrating a reflected wave when the measurement surface of the blood vessel diameter measurement device is positioned parallel to the blood vessel wall. FIG. 13 is a diagram illustrating a cross section in the radial direction of a blood vessel, illustrating a reflected wave when the measurement surface of the blood vessel diameter measurement device and the blood vessel wall are no longer positioned parallel to each other due to body movement. FIG. 13 is a diagram illustrating a cross section of a blood vessel in the axial direction, illustrating a reflected wave when the measurement surface of the blood vessel diameter measuring device and the blood vessel wall are no longer parallel due to body movement. FIG. 1 is a diagram illustrating an axial cross section of a blood vessel, illustrating reflected waves when the measurement surface of the blood vessel diameter measurement device is parallel to the blood vessel wall in a first embodiment of the ultrasonic measurement device and ultrasonic measurement method according to the present invention. FIG. 1 is a diagram illustrating an axial cross section of a blood vessel, illustrating reflected waves when the measurement surface of the blood vessel diameter measurement device and the blood vessel wall are no longer parallel due to body movement, in a first embodiment of the ultrasonic measurement device and ultrasonic measurement method according to the present invention. 3 is an exploded perspective view showing a method for manufacturing the ultrasonic radiation detection unit of the first embodiment of the ultrasonic measurement device according to the present invention. FIG. 1 is a side view showing an example of an ultrasonic radiation detection unit of a first embodiment of an ultrasonic measurement device according to the present invention. FIG. 1 is a side view showing an example of an ultrasonic radiation detection unit of a first embodiment of an ultrasonic measurement device according to the present invention. FIG. FIG. 11 is a schematic configuration diagram showing a second embodiment of an ultrasonic measurement device according to the present invention. FIG. 11 is a perspective view showing an example of a second embodiment of an ultrasonic measurement device according to the present invention. FIG. 11 is a perspective view showing an example of a second embodiment of an ultrasonic measurement device according to the present invention. FIG. 11 is a perspective view showing a measurement in a third embodiment of an ultrasonic measurement device according to the present invention. FIG. 13 is a perspective view showing an example of a third embodiment of an ultrasonic measurement device according to the present invention. FIG. 13 is a perspective view showing an example of a third embodiment of an ultrasonic measurement device according to the present invention. FIG. 11 is a perspective view showing an ultrasonic radiation detection unit of a fourth embodiment of an ultrasonic measurement device according to the present invention. 13 is a cross-sectional view showing an ultrasonic radiation detection unit of a fourth embodiment of an ultrasonic measurement device according to the present invention. FIG. 10A to 10C are process diagrams showing a manufacturing process of an ultrasonic radiation detection unit of a fourth embodiment of an ultrasonic measurement device according to the present invention. 10A to 10C are process diagrams showing a manufacturing process of an ultrasonic radiation detection unit of a fourth embodiment of an ultrasonic measurement device according to the present invention. 10A to 10C are process diagrams showing a manufacturing process of an ultrasonic radiation detection unit of a fourth embodiment of an ultrasonic measurement device according to the present invention. 10A to 10C are process diagrams showing a manufacturing process of an ultrasonic radiation detection unit of a fourth embodiment of an ultrasonic measurement device according to the present invention. FIG. 13 is a schematic cross-sectional view showing an ultrasonic radiation detection unit of a fifth embodiment of an ultrasonic measurement device according to the present invention. 13 is a schematic cross-sectional view showing an ultrasonic radiation detection unit of a sixth embodiment of an ultrasonic measurement device according to the present invention. FIG. 11 is a graph showing the angular dependence of reflected wave intensity in the vascular axis direction in an embodiment of the present invention. 13 is a graph showing the angle dependence of blood vessel diameter values in the blood vessel axis direction in an example of the present invention. 13 is a graph showing the angular dependence of reflected wave intensity in the vascular axis direction in an example. 13 is a graph showing the angle dependence of blood vessel diameter values in the blood vessel axis direction in an example. 13 is a schematic diagram showing a transmission state in an ultrasonic radiation detection unit of a seventh embodiment of an ultrasonic measurement device according to the present invention; FIG. 13 is a schematic diagram showing a receiving state in an ultrasonic radiation detection unit of a seventh embodiment of an ultrasonic measurement device according to the present invention. FIG.

The first embodiment of the ultrasonic measurement device and ultrasonic measurement method according to the present invention will be described below with reference to the drawings.

1 is a schematic diagram showing a blood vessel diameter measuring device and a blood vessel diameter measuring method according to the present embodiment. In the figure, reference numeral 1 denotes an ultrasonic measuring device (blood vessel diameter measuring device).
The ultrasonic measurement device (blood vessel diameter measurement device) 1 according to this embodiment irradiates ultrasonic waves to measure (measure) an interface having a difference in acoustic impedance. An example of an interface having a difference in acoustic impedance is an interface between biological soft tissue and blood. The interface shape of the acoustic impedance to be measured is assumed to be approximately cylindrical.

As shown in FIG. 1, the blood vessel diameter measuring device 1 according to this embodiment is attached to the body surface K1 of a subject K and measures the blood vessel diameter d of an artery (blood vessel) D. It has an ultrasonic emission detection unit 10 and a control unit 20.

The ultrasonic emission detection unit 10 is attached in a position where ultrasonic waves can be irradiated onto a blood vessel (artery) D that is close to the body surface K1 and easy to measure, such as the radial artery on the inside of the wrist. As a blood vessel diameter sensor, the ultrasonic emission detection unit 10 transmits pulse signals or burst signals of several MHz to several tens of MHz, and measures the arrival time of the reflected waves from the blood vessel wall of the blood vessel D using the transmitted and received waves.

The ultrasonic emission detection unit 10 has a configuration capable of transmitting and receiving ultrasonic waves.
Typically, a piezoelectric element such as PZT can be used as the ultrasonic radiation detection unit 10. The ultrasonic radiation detection unit 10 receives a pulse voltage Pv from the control unit 20 to transmit ultrasonic waves from the radiation detection surface 11, and also receives reflected waves and outputs an output voltage Ev to the control unit 20.
The ultrasonic wave emitted by the ultrasonic radiation detector 10 is radially radiated in at least one direction, as will be described later.

The control unit 20 drives the ultrasonic emission detection unit 10 to enable transmission and reception of ultrasonic waves. The control unit 20 acts as a pulsar receiver. The control unit 20 has a calculation unit that performs necessary calculations using the signal output from the ultrasonic emission detection unit 10, and can output the calculation results. In addition, the control unit 20 can also be equipped with a memory unit that stores data on the calculation results, a transmission unit for output to the outside, etc. The control unit 20 may also be equipped with a power supply unit that drives the ultrasonic emission detection unit 10, etc.

The ultrasonic radiation detection unit 10 is stored in a case 2. The case 2 may also store a control unit 20. A solid gel 3 can be provided in the case 2 at a position where it is to be brought into contact with the body surface K1 for measurement. The solid gel 3 can be made of, for example, polyurethane gel, acrylic gel, or the like. The solid gel 3 adheres closely to the body surface K1 to stabilize the measurement by the ultrasonic radiation detection unit 10. The solid gel 3 has an acoustic impedance close to that of a living body during measurement, and prevents attenuation of ultrasonic waves due to reflection. The radiation detection surface 11 is in contact with the solid gel 3.

Next, measurement of blood vessel diameter by the blood vessel diameter measuring device 1 will be described.
In measurements using the blood vessel diameter measuring device 1, the blood vessel diameter measuring device 1 is attached so that the solid gel 3 is in contact with the body surface K1. At this time, since the blood vessel D extends along the body surface K1, the blood vessel D has four interfaces, namely, the outermost circumferential blood vessel wall surface D1 located close to the body surface K1, the inner circumferential blood vessel wall surface D2 located close to the body surface K1, the inner circumferential blood vessel wall surface D3 located away from the body surface K1, and the outermost circumferential blood vessel wall surface D4 located away from the body surface K1, which are transitions in acoustic impedance and can reflect irradiated ultrasound.

Fig. 2 is a graph illustrating the time variation of measurement data of reflected waves in the blood vessel diameter measurement device and blood vessel diameter measurement method of this embodiment. Fig. 3 is a graph illustrating the relationship between blood vessel diameter measured by the blood vessel diameter measurement device and blood vessel diameter measurement method of this embodiment and time.
As shown in Fig. 2, at time T0, an ultrasonic wave is emitted from the emission detection surface 11. At time T1, a vertical reflected wave RU1 from the blood vessel wall surface D1 closest to the emission detection surface 11 is received by the emission detection surface 11. Furthermore, at time T2, a vertical reflected wave RU2 from the blood vessel wall surface D2 next closest to the emission detection surface 11 is received by the emission detection surface 11. At time T3, a vertical reflected wave RU3 from the blood vessel wall surface D3 next closest to the emission detection surface 11 is received by the emission detection surface 11. At time T4, a vertical reflected wave RU4 from the blood vessel wall surface D4 furthest from the emission detection surface 11 is received by the emission detection surface 11.

As shown in Figure 1, vascular wall surface D2 and vascular wall surface D3 are the interface between the vascular wall and blood, so this distance directly affects the blood flow rate. For this reason, the time difference between the vertical reflected wave RU2 and the vertical reflected wave RU3, that is, the time difference between time T2 and time T3, is used to calculate the vascular diameter d. The time variation of the vascular diameter d is shown in Figure 3. As shown in Figure 3, it can be seen that pulsation is being measured.

Next, we will explain the shape of the radiation detection surface 11.

4 and 6 are explanatory diagrams showing cross sections along the blood vessel diameter direction, which explain reflected waves in the blood vessel diameter measurement device and blood vessel diameter measurement method, and Fig. 5 and Fig. 7 are explanatory diagrams showing cross sections along the blood vessel axis direction, which explain reflected waves in the blood vessel diameter measurement device and blood vessel diameter measurement method.
4 to 7, consider a case where the ultrasonic radiation detection unit 10 is made of a single element and has a planar radiation detection surface 11. When the ultrasonic radiation detection unit 10 is driven, ultrasonic waves are emitted perpendicularly from the radiation detection surface 11. The ultrasonic waves emitted from the radiation detection surface 11 are all parallel.
The ultrasonic waves transmitted from the radiation detection surface 11 are reflected by the blood vessel D. Here, reflection from a blood vessel wall surface D3 is illustrated as an example.

When the position of the emission detection surface 11, which is the measurement surface of the ultrasound emission detection unit 10, and the vascular wall surface D3 are parallel to each other, the reflected ultrasound is reflected vertically by the vascular wall surface D3 as a vertical reflected wave RU3, as shown in Figures 4 and 5, and reaches the emission detection surface 11. At this time, the vertical reflected wave RU3 reaches the emission detection surface 11 without any change in phase from when it was sent out. Furthermore, the vertical reflected wave RU3 received by the emission detection surface 11 has sufficient intensity.
For this reason, the output signal output from the ultrasound emission detection unit 10 in response to the received vertical reflected wave RU3 is not buried in noise, there is no deviation in the reception timing, and maintains an intensity sufficient to calculate the vascular diameter d, as shown in the graph on the right of FIG. 5.

In contrast, if the subject K moves, the blood vessel diameter measuring device 1 may tilt with respect to the blood vessel D. Consider a case where the position of the radiation detection surface 11 and the blood vessel wall surface D3 are tilted from their parallel positions due to the body movement of the subject K.

As shown in FIG. 6, when the blood vessel diameter measuring device 1 is tilted relative to the blood vessel D in a direction along a cross section along the radial direction of the blood vessel D, the blood vessel diameter measuring device 1 can be regarded as moving parallel to the blood vessel D. In other words, the position of the radiation detection surface 11 and the blood vessel wall surface D3 is different from the vertical reflected wave RU3 received when they were parallel to each other, but there is a surface where the radiation detection surface 11 and the blood vessel wall surface D3 are parallel to each other. Therefore, the irradiated ultrasound is reflected vertically by the blood vessel wall surface D3 at this position, becoming the vertical reflected wave RU3. At the same time, the vertical reflected wave RU3 reflected by the blood vessel wall surface D3 at this position reaches the radiation detection surface 11.

Therefore, when the inclination direction of the radiation detection surface 11 is only along the blood vessel radial direction, the vertical reflected wave RU3 received by the radiation detection surface 11 has sufficient intensity. At the same time, the vertical reflected wave RU3 reaches the radiation detection surface 11 with the same phase as when it was sent out.
For this reason, the output signal output from the ultrasound emission detection unit 10 in response to the received vertical reflected wave RU3 maintains an intensity sufficient to allow calculation of the vascular diameter d without being buried in noise, as in the graph shown on the right side of FIG. 5 .

7, when the blood vessel diameter measurement device 1 is inclined relative to the blood vessel D in a direction along the axial direction of the blood vessel D, the radiation detection surface 11 and the blood vessel wall surface D3 do not exist as parallel surfaces. In other words, when the radiation detection surface 11 and the blood vessel wall surface D3 are no longer parallel to each other, the vertical reflected wave RU3 disappears. Therefore, the radiation detection surface 11 cannot receive the vertical reflected wave RU3.
As a result, the ultrasonic radiation detection unit 10 is unable to measure the depth of the blood vessel wall surface D3 and the blood vessel wall surface D2.

Even when the reflected wave reaches the radiation detection surface 11 and can be received, the distance that the reflected wave reflected from the vascular wall surface D3 and the vascular wall surface D2 travels back to the radiation detection surface 11 varies depending on the position of the reflecting surface along the inclination direction, and this can result in a phase shift in the reflected wave.
In this case, if the distances the reflected waves travel to return to the radiation detection surface 11 are different, the phases of the reflected waves will not be aligned, i.e., the reception timing will be shifted, causing the strength of the reflected waves to drop due to the effect of addition. As a result, the radiation detection surface 11 will not be able to receive reflected waves of sufficient strength, making it impossible to use the device for measuring the blood vessel diameter d.

In this way, in order to make it possible to measure the blood vessel diameter d even if the ultrasonic emission detection unit 10 is tilted in the axial direction of the blood vessel D, the blood vessel diameter measurement device 1 of this embodiment employs a means that is capable of transmitting ultrasonic waves tilted at different angles in the axial direction of the blood vessel D, and is provided with an emission detection surface 11 that is capable of receiving all of the reflected waves reflected at these different angles.

8 and 9 are explanatory diagrams showing cross sections along the vascular axis direction, illustrating reflected waves in the blood vessel diameter measurement device and blood vessel diameter measurement method of this embodiment.
Specifically, as shown in FIG. 8, the ultrasonic radiation detection unit 10 has an element unit 13, a backing unit 14, an acoustic lens (acoustic lens unit) 15, and an acoustic matching layer 16.

The element unit 13 is a piezoelectric element made of ceramics having piezoelectric properties such as PZT (lead zirconate titanate), and in this embodiment, has a flat plate shape with flat front and back surfaces. A backing unit 14 is attached to one surface of the element unit 13. An acoustic lens 15 is attached to the other surface of the element unit 13 via an acoustic matching layer 16. The element unit 13 is sandwiched between the backing unit 14 and the acoustic matching layer 16.

The acoustic matching layer 16 is disposed between the element section 13 and the acoustic lens 15. When there is a difference in acoustic impedance between the element section 13 and the measurement target (living body), the acoustic matching layer 16 is formed from a substance having an acoustic impedance value between them. Even when there is a difference in acoustic impedance between the element section 13 and the measurement target (living body), the acoustic matching layer 16 suppresses a decrease in the transmission efficiency of the ultrasonic wave, which is the measurement wave.
The acoustic impedance is a value that indicates the speed at which ultrasonic waves propagate.

Here, the acoustic impedance in the ultrasonic radiation detection unit 10 is as follows, in descending order:
Element section 13 > acoustic lens 15 > acoustic matching layer 16 > blood vessel wall (surrounding area of measurement object; soft biological tissue, etc.) > blood (interface reflection measurement object; equivalent to water)
It is as follows.

An example of a material for the element portion 13 is piezoelectric ceramics.
An example of the material of the acoustic lens 15 is acrylic resin.
An example of the material of the acoustic lens 15 is polyacetal.
An example of the material of the acoustic lens 15 is PET resin.
The acoustic lens 15 can be made of, for example, ABS resin.
An example of the material of the acoustic matching layer 16 is PET resin.
The acoustic matching layer 16 can be made of, for example, ABS resin.
An example of the material of the acoustic matching layer 16 is high density polyethylene.

An example of the acoustic impedance value for each material is shown below.
Piezoelectric ceramics: 30×10 ⁻⁶ to 35×10 ⁻⁶ [kg/m ² sec]
Acrylic resin: 3×10 ⁻⁶ to 3.61×10 ⁻⁶ [kg/m ² sec]
Polyacetal: 3.12×10 ⁻⁶ to 3.34×10 ⁻⁶ [kg/m ² sec]
・PET resin; 2.85×10 ^-6 ~2.95×10 ^-6 [kg/m ² sec]
・ABS resin; 2.21×10 ^-6 ~2.28×10 ^-6 [kg/m ² sec]
High density polyethylene: 2.01×10 ⁻⁶ to 2.16×10 ⁻⁶ [kg/m ² sec]
Biological soft tissue (fat, muscle, etc.): 1.35×10 ⁻⁶ to 1.68×10 ⁻⁶ [kg/m ² sec]
・Water; 1.5×10 ⁻⁶ [kg/m ² sec]
・Blood; 1.60×10 ⁻⁶ [kg/m ² sec]
Here, the blood and the biological soft tissue correspond to the measurement objects located on either side of the interface.

The acoustic matching layer 16 is disposed integrally with the element portion 13, so it will not be mentioned specifically in the following description.

The backing portion 14 acts as a support for fixing the element portion 13 to the case 2 or the like. The backing portion 14 to which the element portion 13 is attached is formed to absorb ultrasonic waves and prevent excess vibrations from being directed elsewhere. The backing portion 14 has a predetermined hardness and strength, and can be made of resin, which is an insulating material, or metal.

The acoustic lens 15 acts as a lens that refracts ultrasonic waves of a predetermined frequency. The acoustic lens 15 exhibits a predetermined propagation speed for ultrasonic waves of this frequency and is formed from a resin or the like that exhibits transparency for ultrasonic waves of this frequency. The acoustic lens 15 can be made of, for example, acrylic resin. The acoustic lens 15 constitutes an acoustic lens section. The acoustic lens section acts as a lens that refracts ultrasonic waves of a predetermined frequency. The acoustic lens section is not limited to a lens as long as it has the function of refracting ultrasonic waves.

One surface of the acoustic lens 15 to which the element portion 13 is attached is formed in a flat shape. The other surface of the acoustic lens 15 is formed as a curved, convex surface such that the central portion is farther away from the element portion 13 than the peripheral portion. The curved surface of the acoustic lens 15 constitutes the radiation detection surface 11. In this case, the acoustic lens 15 is formed so that the peripheral portion is thinner than the central portion. The acoustic lens 15 is formed so that the central portion is thicker than the peripheral portion.

The other surface of the acoustic lens 15 can also be formed as a curved surface that is curved and concave so that the peripheral portion is farther away from the element portion 13 than the central portion. The curved surface of the acoustic lens 15 forms the radiation detection surface 11. In this case, the acoustic lens 15 is formed so that the central portion is thinner than the peripheral portion.

Here, if acoustic lens 15 is a concave lens with a concave surface, the focal point will be outside in the radiation direction, but if the size/radius of curvature is the same, the radiation angle will be the same as with a convex lens. For example, if acoustic lens 15 is made of acrylic, and the speed of sound within acoustic lens 15 is faster than the speed of sound within body tissue, the inclination of the ultrasound bent by the concave surface relative to the ultrasound transmitted from the radiation surface of the element unit will be the same as in the case of a convex lens.

In contrast, if the acoustic lens 15 is made of silicone rubber, for example, and the speed of sound within the acoustic lens 15 is slower than the speed of sound within body tissue, the ultrasound transmitted from the radiation surface of the element will be bent in the opposite direction to the radiation direction of the ultrasound bent by the concave surface, but the effect of the lens can be expected.

In the case of a convex lens and a concave lens made of acrylic, when a radiation angle of ±9° is obtained, the radius of curvature R can be set to 6 mm. In the case of a convex lens and a concave lens made of acrylic, when a radiation angle of ±16° is obtained, the radius of curvature R can be set to 3.6 mm.
In the case of convex and concave lenses made of silicone rubber, when a radiation angle of ±9° is obtained, the radius of curvature R can be set to 6.9 mm. In the case of convex and concave lenses made of silicone rubber, when a radiation angle of ±16° is obtained, the radius of curvature R can be set to 4.4 mm.

The surface of the element portion 13 on which the acoustic lens 15 is attached constitutes a radiation detection element surface 13a.
In the planar radiation detection element surface 13a of the element portion 13, ultrasonic waves are transmitted in a direction perpendicular to the radiation detection element surface 13a (normal direction).

The ultrasonic waves emitted from the radiation detection element surface 13a of the element portion 13, which is planar, pass through the inside of the acoustic lens 15 and are emitted from the radiation detection surface 11 of the acoustic lens 15, which is a curved surface. At the radiation detection surface 11 of the acoustic lens 15, the ultrasonic waves are emitted radially from the radiation detection surface 11, which is a curved surface.

That is, the ultrasonic waves transmitted from the radiation detection surface 11 are emitted in the central portion of the radiation detection surface 11, which is a curved surface, along the normal direction of the radiation detection element surface 13a.
In contrast, at the peripheral portion of the radiation detection surface 11, which is a curved surface, the radiation is emitted at an angle in the direction in which the thickness of the acoustic lens 15 decreases with respect to the normal direction of the radiation detection element surface 13a.

Therefore, on the curved radiation detection surface 11, ultrasonic waves are emitted at a larger inclination angle from the peripheral portion than from the central portion.

As long as the radiation detection surface 11 of this embodiment is curved in at least one direction along the axial direction of the blood vessel D, it is sufficiently possible to measure the blood vessel diameter d. Therefore, the radiation detection surface 11 of this embodiment can be formed as a shape having a curvature in one direction. That is, the radiation detection surface 11 can be formed, for example, as a part of a cylindrical surface, with both ends cut along the axis of the cylinder. Note that the radiation detection surface 11 can also be a curved surface that has a curvature in a direction that intersects with the one direction that forms the curved surface described above. An example of such a curved surface of the radiation detection surface 11 is a spherical surface.

As shown in FIG. 8, the ultrasound emission detection unit 10 of this embodiment is not inclined in the axial direction of the blood vessel D, and when the emission detection element surface 13a and the blood vessel wall surface D3 are parallel to each other, the ultrasound emitted radially returns from the emission detection surface 11 to the emission detection element surface 13a as a vertical reflected wave RU3. Therefore, the emission detection surface 11 and the emission detection element surface 13a can receive a vertical reflected wave RU3 with no phase change and sufficient intensity.

As shown in FIG. 9, the ultrasonic radiation detection unit 10 of this embodiment is tilted in the axial direction of the blood vessel D due to the body movement of the subject K, and even when the radiation detection element surface 13a and the blood vessel wall surface D3 are tilted relative to each other, among the ultrasonic waves emitted radially, ultrasonic waves emitted in either direction return from the radiation detection surface 11 to the radiation detection element surface 13a as vertical reflected waves RU3. Therefore, even when the radiation detection element surface 13a and the blood vessel wall surface D3 are tilted relative to each other, the radiation detection surface 11 and the radiation detection element surface 13a can receive vertical reflected waves RU3 with no phase change and sufficient intensity.

FIG. 10 is an exploded perspective view showing a method for manufacturing an ultrasonic radiation detection unit in the blood vessel diameter measurement device and blood vessel diameter measurement method of this embodiment.
As shown in FIG. 10, the ultrasonic radiation detection unit 10 of this embodiment has an acoustic lens 15 attached in intimate contact with an element unit 13 fixed to a backing unit 14 .
The ultrasonic emission detection unit 10 can also be assembled by adhering, with an adhesive or the like, the acoustic lens 15, which has a curved surface with a predetermined curvature, and the element unit 13, which is fixed to the backing unit 14. It is also possible to mold the acoustic lens 15, which has a curved surface with a predetermined curvature, by placing the element unit 13, which is fixed to the backing unit 14, in a predetermined mold, which has a space corresponding to the acoustic lens 15, and pouring a predetermined resin, such as acrylic, into the space in the mold, and at the same time, to form the acoustic lens 15 integrally with the element unit 13.

11 and 12 are a cross-sectional view and a perspective view showing examples of an acoustic lens in an ultrasonic radiation detector in the blood vessel diameter measurement device and blood vessel diameter measurement method of this embodiment.
11 and 12, the ultrasonic radiation detection unit 10 of this embodiment can set the angle between the normal line of the radiation detection element surface 13a and the radiation detection surface 13a to a predetermined transmission angle range as shown in the figures as the transmission range of ultrasonic waves. At the same time, the thickness dimension of the end of the acoustic lens 15 and the curvature radius of the radiation detection surface 11 are also shown. These are examples corresponding to the type, thickness, curvature, depth from the body surface, and ease of body movement of the blood vessel D to be measured.

The blood vessel diameter measuring device and blood vessel diameter measuring method of the present invention are not limited to these numerical ranges, but the ranges described are preferable ranges when practically performing measurements on the human body.
When the transmission angle range is ±9°, the ultrasound emission detection unit 10 of this embodiment can perform measurements even when the radiation detection element surface 13a is tilted up to about 5° with respect to the axial direction of the blood vessel D. Similarly, when the transmission angle range is ±16°, the ultrasound emission detection unit 10 of this embodiment can perform measurements even when the radiation detection element surface 13a is tilted up to about 8° with respect to the axial direction of the blood vessel D.

The blood vessels D to be measured are preferably large blood vessels located close to the body surface K1 and easily accessible, such as the radial artery, carotid artery, subclavian artery, other limb arteries, and arteries behind the ankle.

If the resolution is about 1/20 or less of the time fluctuation width of the blood vessel diameter d, it is possible to provide the distance resolution required for measuring the pulse from the blood vessel diameter d. When the above blood vessel is the measurement target, if the time fluctuation width of the blood vessel diameter d is about 0.1 mm, it is preferable to set the distance resolution in the ultrasonic emission detection unit 10 of this embodiment to about 5 μm.

Reducing the area of the radiation detection element surface 13a in the element section 13 makes it easier to handle and reduces the weight of the ultrasonic radiation detection section 10, making it lighter and more compact. Increasing the area of the radiation detection element surface 13a in the element section 13 makes it possible to increase the measurable range. The size of the radiation detection element surface 13a can be approximately 2 mm to 20 mm in diameter. The size in the axial direction corresponding to the radiation detection element surface 13a in the element section 13 can be approximately 2 mm to 20 mm.

In the blood vessel diameter measurement device 1 of this embodiment, data of vertically reflected waves RU measured by the ultrasonic emission detection unit 10 is output as an output signal to the control unit 20. The control unit 20 calculates the blood vessel diameter d, and outputs blood pressure and pulsation data calculated from the time variation of this blood vessel diameter d.
The ultrasonic radiation detection unit 10 radially transmits and receives ultrasonic waves with the radiation detection surface 11 formed as a curved surface, making it possible to perform accurate measurements and continuously output accurate blood pressure and pulsation data even if the relative position between the ultrasonic radiation detection unit 10 and the blood vessel D changes due to bodily movement. Therefore, by constantly wearing the blood vessel diameter measurement device 1, it becomes possible to continuously obtain accurate blood pressure and pulsation data of the measurement subject K, regardless of the presence or absence of bodily movement.

Furthermore, this embodiment has the advantage that the subject is not subjected to pain such as pressure during measurement because ultrasound is used, and is not affected by changes in blood vessel diameter or blood pressure due to being conscious of the measurement.

Hereinafter, a second embodiment of an ultrasonic measurement device and an ultrasonic measurement method according to the present invention will be described with reference to the drawings.
13 is a schematic diagram showing the configuration of a blood vessel diameter measurement device and a blood vessel diameter measurement method according to this embodiment. This embodiment differs from the first embodiment described above in terms of the control unit, and other configurations corresponding to those of the first embodiment described above are given the same reference numerals and descriptions thereof will be omitted.

As shown in FIG. 13 , the blood vessel diameter measurement device 1 in this embodiment has, as a control unit 20, a printed circuit board 21 to which the solid gel 3 and the ultrasound emission detection unit 10 are fixed, a driver circuit unit 23 provided on the printed circuit board 21, an arithmetic processing circuit unit 24 provided on the printed circuit board 21, a power supply unit 22 as a battery connected to the driver circuit unit 23 and the arithmetic processing circuit unit 24 via the printed circuit board 21, a display unit 25 as a display connected to the arithmetic processing circuit unit 24 and from which data is output, and a wireless module unit 26 connected to the arithmetic processing circuit unit 24 and from which data is output.
13 , the blood vessel diameter measurement device 1 in this embodiment is arranged so that the solid gel 3 and the ultrasound radiation detection unit 10 are exposed from the back surface 2a of the case 2. A display unit 25 is arranged on the front surface 2b of the case 2.

In this embodiment, the blood vessel diameter measuring device 1 controls the ultrasonic emission detection unit 10 by the driver circuit unit 23, which is supplied with driving power from the power supply unit 22 as a driving power source. The ultrasonic emission detection unit 10, controlled by the driver circuit unit 23, transmits and receives ultrasonic waves to measure the vertical reflected wave RU. The ultrasonic emission detection unit 10 outputs the acquired measurement data of the vertical reflected wave RU to the arithmetic processing circuit unit 24. The arithmetic processing circuit unit 24 calculates data of the blood vessel diameter d based on the measurement data of the vertical reflected wave RU output from the ultrasonic emission detection unit 10.

The arithmetic processing circuit unit 24 calculates blood pressure, etc. from the time variation data of this blood vessel diameter d. The arithmetic processing circuit unit 24 outputs the blood vessel diameter data, blood pressure, etc. to the display unit 25. The display unit 25 displays this blood vessel diameter data, blood pressure, etc. At the same time, the arithmetic processing circuit unit 24 outputs the blood vessel diameter data, blood pressure, etc. to the wireless module unit 26. The wireless module unit 26 transmits the blood vessel diameter data, blood pressure, etc. to a smartphone or a memory unit 27 (described later) which is a medical device, etc.

The arithmetic processing circuit unit 24 can perform various arithmetic processing and correction when calculating blood pressure and the like from the time variation data of the blood vessel diameter d.
For example, the control unit 20 may be provided with an acceleration sensor (not shown) and, from its output, the motion state of the measurement subject K wearing the blood vessel diameter measurement device 1 may be detected and the blood vessel diameter data may be corrected based on this motion state.

The control unit 20 is equipped with an air pressure sensor (not shown) and can detect the ambient pressure around the subject K wearing the blood vessel diameter measuring device 1 from its output, and can perform correction processing of the blood vessel diameter data from this ambient pressure.

The blood vessel diameter measuring device 1 in this embodiment is capable of constantly measuring blood vessel diameter data by attaching the solid gel 3 and the ultrasonic radiation detection unit 10 so that they are fixed at the measurement position of the subject K. At the same time, the blood vessel diameter measuring device 1 is capable of continuously displaying the blood vessel diameter data on the display unit 25 and constantly transmitting it to the memory unit 27.

FIG. 14 is a schematic perspective view showing another example of the blood vessel diameter measurement device and blood vessel diameter measurement method according to this embodiment.
14 , the blood vessel diameter measurement device 1 in this embodiment can include a wrist band 31 as the fixing part 30 for the measurement subject K to wear the case 2. In this case, the wrist band 31 and the case 2 constitute the fixing part 30.

In another example of the blood vessel diameter measuring device 1 of this embodiment, when the blood vessel diameter measuring device 1 is worn, the line connecting both ends of the case 2 to which the wrist band 31 is connected crosses the direction along the blood flow of the radial artery, i.e., the axial direction of the blood vessel D. The radiation detection surface 11 of the ultrasound emission detection unit 10 can transmit ultrasound radially along the line connecting both ends of the case 2 to which the wrist band 31 is not connected. An adjustment mechanism can be provided that can rotate the ultrasound emission detection unit 10 relative to the wrist band 31 and the case 2 and adjust the curvature direction of the radiation detection surface 11 in the extension direction of the blood vessel D to be detected.

In this example, the subject K can wear the blood vessel diameter measuring device 1 so that the solid gel 3 on the back surface 2a of the case 2 is located near the radial artery in the wrist. This makes it easy to wear the blood vessel diameter measuring device 1 without interfering with daily life, making it easy to constantly obtain blood vessel diameter data.

Figure 15 is a schematic perspective view showing another example of a blood vessel diameter measurement device and a blood vessel diameter measurement method according to this embodiment.

In another example of the blood vessel diameter measurement device 1 of this embodiment, as shown in FIG. 15, a smartphone is used as the storage unit 27. The smartphone as the storage unit 27 enables continuous transmission and storage of blood vessel diameter data from the blood vessel diameter measurement device 1.

In this example, the subject K constantly wears the vascular diameter measuring device 1 and constantly transmits vascular diameter data from the wireless module 26 to the memory 27, making it possible to continuously acquire vascular diameter data and store the vascular diameter data in the smartphone as the memory 27. This makes it easy for the subject K to check the accumulated vascular diameter data himself and to present the accumulated vascular diameter data to medical professionals, etc.

This embodiment can achieve the same effect as the above-mentioned embodiment. This embodiment can achieve the effect of notifying not only medical professionals but also family members of abnormalities, and providing information to service providers.

Hereinafter, a third embodiment of an ultrasonic measurement device and an ultrasonic measurement method according to the present invention will be described with reference to the drawings.
16 is a perspective view showing a blood vessel diameter measurement device and a blood vessel diameter measurement method according to this embodiment. This embodiment differs from the first and second embodiments described above in terms of the fixing unit, and other configurations corresponding to those of the first and second embodiments described above are given the same reference numerals and descriptions thereof will be omitted.

As shown in FIG. 16, the blood vessel diameter measuring device 1 of this embodiment has a case 2 formed in a disk shape about the size of a coin. The blood vessel diameter measuring device 1 has a wiring section 28 that transmits data to the outside as a control section 20. In the blood vessel diameter measuring device 1, the case 2 does not have a display section 25 or a wireless module section 26.

In this embodiment, the control unit 20 may not be stored inside the case 2. In this case, the wiring unit 28 connected to the ultrasonic radiation detection unit 10 inside the case 2 may be pulled out to the outside of the case 2, and the control unit 20 and the like may be stored in another device outside the case 2, and the ultrasonic radiation detection unit 10 and the control unit 20 may be connected by the wiring unit 28.

It is also possible to store only the power supply unit 22 and the driver circuit unit 23 inside the case 2, and store the arithmetic processing circuit unit 24 and other components in another device outside the case 2, and connect the arithmetic processing circuit unit 24 and other components via the wiring unit 28.

When acquiring blood vessel diameter data using the blood vessel diameter measuring device 1 of this embodiment, as shown in FIG. 16, the back surface 2a of the case 2 is brought into contact with the body surface K1 in the vicinity of the blood vessel D to be measured, and the front surface 2b is fixed in place by slightly pressing it toward the body surface K1 with a finger or the like.

As a result, as in the above-described embodiment, data on the vertical reflected wave RU can be accurately obtained. Regardless of whether it is inside or outside case 2, data on the blood vessel diameter d and blood pressure estimates, etc. can be obtained.

In this example, data acquisition from the radial artery is illustrated as an example, but even when acquiring data from the carotid artery or the like, the case 2 can be attached with surgical tape or the like to easily fix the blood vessel diameter measuring device 1 to the body surface K1, which is the measurement position, for accurate measurement. This makes it easy to acquire blood vessel diameter data even from a measurement subject K who has been brought to the hospital by ambulance and is unconscious. As the blood vessel diameter measuring device 1 has a case 2 about the size of a coin, it is easy to handle and improves operability.

FIG. 17 is a perspective view showing another example of the blood vessel diameter measuring device and the blood vessel diameter measuring method according to this embodiment.
In this example, as shown in Fig. 17, the coin-shaped case 2 is attached to the inner circumference of a stretchable band 32 made of rubber or the like. Therefore, similar to the examples shown in Figs. 15 and 16, it is easy to wear on the wrist. The stretchable band 32 may be a wristwatch band or the like, similar to the examples shown in Figs. 15 and 16, or it may simply be configured as a stretchable net bandage. Note that the wiring portion 28 is omitted in the figure.

In this example, the case 2 is attached to the elastic band 32, which is the fixing part 30, by means of reattachable double-sided tape 32a or the like. When wearing the blood vessel diameter measurement device 1, for example, the case 2 can be rotated to match the direction in which the radial artery extends when worn on the wrist, and then the case 2 can be reattached to the elastic band 32. This makes it possible to easily adjust the curvature direction of the radiation detection surface 11 so as to improve measurement accuracy.
Furthermore, an arrow 2 d indicating the curvature direction of the radiation detection surface 11 may be displayed on the surface of the case 2 .

FIG. 18 is a perspective view showing another example of the blood vessel diameter measurement device and the blood vessel diameter measurement method according to this embodiment.
18, the fixing part 30 has a flexible film material 33 with a sticky adhesive applied to one side thereof. The case 2 is attached to the sticky surface of the film material 33. In this example, the case 2 can be reattached to the sticky surface of the film material 33, as in the above example.
In this example, it is suitable for use in acquiring data from the carotid artery and the subclavian artery.

In this embodiment, the same effect as the above-mentioned embodiment can be achieved. In this embodiment, when measuring the subclavian artery or carotid artery, it is difficult to fix the blood vessel diameter measurement device with a band or the like, but this problem can be solved, and the blood vessel diameter measurement device is in close contact with the skin compared to fixation with a band or the like, and is less likely to shift due to body movement.

Hereinafter, a fourth embodiment of an ultrasonic measurement device and an ultrasonic measurement method according to the present invention will be described with reference to the drawings.
19 is a perspective view showing a blood vessel diameter measurement device and a blood vessel diameter measurement method according to this embodiment. This embodiment differs from the first to third embodiments described above in terms of the formation of the radiation detection surface, and other configurations corresponding to those of the first to third embodiments described above are given the same reference numerals and descriptions thereof will be omitted.

As shown in FIG. 19, the blood vessel diameter measurement device 1 in this embodiment does not include an acoustic lens, and the element section 13 itself is curved. The radiation detection element surface 13a forms the radiation detection surface 11. It is preferable that the curvature, etc. of the radiation detection element surface 13a be set to the dimensions shown in FIG. 19.

FIG. 20 is a cross-sectional view showing the ultrasonic emission detection unit 10 in this embodiment.
In the blood vessel diameter measurement device 1 of this embodiment, the element section 13 has a plurality of elements 13A, as shown in Fig. 20. In the element section 13, the plurality of elements 13A are arranged in a curved combination so as to form the radiation detection surface 11. The plurality of elements 13A are arranged in a curved combination so that each radiation detection element surface 13a forms the radiation detection surface 11. In the element section 13, insulating spacer sections 13f made of epoxy resin or the like are arranged between the plurality of elements 13A. The plurality of elements 13A and spacer sections 13f that constitute the element section 13 are formed in the shape of a curved plate.

The curved plate-like element portion 13 is fixed to the curved protrusion 14d of the backing portion 14. In the curved plate-like element portion 13, upper electrodes 13g and lower electrodes 13h are formed on both sides of the multiple elements 13A and the spacer portion 13f. In the protrusion 14d, the upper electrode 13g and the lower electrode 13h sandwich the multiple elements 13A and the spacer portion 13f that are the element portion 13.

The upper electrode 13g and the lower electrode 13h are formed beyond the range of the elements 13A and the spacer portion 13f that constitute the element portion 13, up to the peripheral portion 14h where there is no protruding portion 14d. In the peripheral portion 14h, an insulating layer 13j is disposed between the upper electrode 13g and the lower electrode 13h. In the peripheral portion 14h, the insulating layer 13j is sandwiched between the upper electrode 13g and the lower electrode 13h.
The upper electrode 13g and the lower electrode 13h are each connected to the control unit 20 at positions not shown.

In the ultrasonic radiation detection unit 10 of this embodiment, the multiple elements 13A are arranged with their crystal planes tilted so that they can transmit and receive ultrasonic waves along the radiation detection surface 11. In the element unit 13, the multiple elements 13A are arranged in an array so that the tilt angle increases from the center to the peripheral portion of the element unit 13. The element planes of the multiple elements 13A are each arranged so as to be tilted along the radiation detection surface 11 at the position where they are arranged in the array.
In this embodiment, the multiple elements 13A simultaneously emit ultrasonic waves.

The ultrasonic emission detection unit 10 in this embodiment, like the above-mentioned embodiment, can transmit ultrasonic waves radially and receive vertical reflected waves RU with no phase change with sufficient intensity.

Next, a method for manufacturing the ultrasonic radiation detection unit 10 in this embodiment will be described.

21 to 24 are process diagrams showing a method for manufacturing the ultrasonic radiation detection unit 10 in this embodiment.
In the method of manufacturing the ultrasonic radiation detection unit 10 in this embodiment, first, as shown in Fig. 21(a), a piezoelectric material 13A0 such as PZT that will become the element 13A is formed in a planar shape on a predetermined substrate (silicon substrate) 130S. In this case, the piezoelectric material 13A0 is formed on the silicon substrate 130S by a method such as sputtering, or is formed in a separate process and then placed on the silicon substrate 130S.

Next, as shown in FIG. 21(b), a predetermined area of the piezoelectric material 13A0 is removed on the silicon substrate 130S to produce a piezoelectric material 13A1 that is divided into a predetermined width.

Next, as shown in FIG. 22(c), spacer resin 13f1 is filled between the piezoelectric materials 13A1 on the silicon substrate 130S to serve as spacers. Epoxy or the like is used as the spacer resin 13f1.

Similarly, a predetermined width of the piezoelectric material 13A1 and the spacer resin 13f1 are removed in a direction perpendicular to Fig. 21(b), and the removed gap is filled with the spacer resin 13f1 as in Fig. 22(c). This makes it possible to form a planar front element portion 13Aa in which a plurality of elements 13A2 made of piezoelectric material whose plane is divided vertically and horizontally and the gaps are filled with the spacer resin 13f2, as shown in Fig. 22(d).
In this state, the element surfaces of the multiple elements 13A2 are all flat surfaces facing the same direction along the surface of the silicon substrate 130S, so that ultrasonic waves cannot be emitted radially.

Next, as shown in FIG. 23(a), a backing portion 14 is prepared, which has a curved convex portion 14d and a planar peripheral portion 14h around the curved convex portion 14d.

Next, as shown in FIG. 23(b), a conductive lower electrode 13h such as a metal is formed to cover the curved convex portion 14d and the peripheral portion 14h. After the lower electrode 13h is formed over the entire surface of the backing portion 14, the unnecessary portions are removed while leaving the specified portions. The lower electrode 13h is formed using a specified method such as sputtering or welding. The lower electrode 13h is removed using a method such as etching.

Next, as shown in FIG. 23(c), a conductive adhesive 13ha is applied to the surface of the lower electrode 13h that corresponds to the curved convex portion 14d.

Next, as shown in FIG. 23(d), a mold 131 made of aluminum or the like is prepared, which has a curved recess 131d corresponding to the protrusion 14d. A planar front element portion 13Aa is placed in the opening of the curved recess 131d so as to close the opening.

24(e), the convex portion 14d formed on the lower electrode 13h is pressed together with the planar front element portion 13Aa into the inside of the curved concave portion 131d. At this time, pressure and heat treatment may also be applied.
The planar front element portion 13Aa curves along the inner surface of the curved recess 131d to become the front element portion 13Ab. In the front element portion 13Ab, the surfaces of the respective elements 13A2 are curved along the inner surface of the curved recess 131d. At the same time, in the front element portion 13Ab, the spacer resin 13f2 is deformed to form the spacer portion 13f.
The elements 13A2 are simply inclined along the convex portion 14d and the curved concave portion 131d, and the piezoelectric characteristics of the elements 13A2 do not change whether they are flat or curved. Therefore, the element surfaces of the elements 13A2 that transmit and receive ultrasonic waves are inclined along the convex portion 14d and the curved concave portion 131d.

Then, as shown in FIG. 24(f), the mold 131 is removed.

Next, as shown in FIG. 24(g), an insulating layer 13j is formed on the peripheral portion 14h. At this time, the insulating layer 13j is not formed in the region corresponding to the front element portion 13Ab.

Next, as shown in FIG. 24(h), the upper electrode 13g is laminated on the front element portion 13Ab and the insulating layer 13j, and is molded into a predetermined shape to form the element portion 13 on the backing portion 14. This completes the ultrasonic radiation detection portion 10.

The ultrasonic radiation detection unit 10 in this embodiment does not use an acoustic lens, so it can be made small, lightweight, and thin.

In this embodiment, the same effect as the above-mentioned embodiment can be achieved. In addition, in this embodiment, the attenuation at the acoustic lens interface is small, and the received strength of the reflected wave is improved compared to when an acoustic lens is used.

Hereinafter, a fifth embodiment of an ultrasonic measurement device and an ultrasonic measurement method according to the present invention will be described with reference to the drawings.
25 is a schematic cross-sectional view showing a blood vessel diameter measurement device and a blood vessel diameter measurement method according to this embodiment. This embodiment differs from the above-mentioned fourth embodiment in terms of the element section, and other configurations corresponding to those of the above-mentioned fourth embodiment are given the same reference numerals and their description will be omitted.

In the blood vessel diameter measuring device 1 of this embodiment, as shown in FIG. 25, the element section 13 has a plurality of elements 13B. The plurality of elements 13B have a planar radiation detection element surface 13Ba. In the element section 13, the plurality of elements 13B are inclined so that they can transmit ultrasound at a radiation angle corresponding to the radiation detection surface 11. Note that, unlike the fourth embodiment, the plurality of elements 13B are merely arranged in an inclined array, and are not arranged so that their positions are curved relative to one another along the radiation detection surface 11.

Unlike the fourth embodiment, insulating spacer portions 13f made of epoxy resin or the like are not disposed between the plurality of elements 13B. The plurality of elements 13B are fixed to the backing portion 14 so as to be embedded in the solid gel 3.
In the ultrasonic radiation detector 10 of this embodiment, an element 13B having a larger size than the element 13A of the fourth embodiment can be used.
In this embodiment, the multiple elements 13B simultaneously emit ultrasonic waves.

In this embodiment, the same effect as the above-mentioned embodiment can be achieved. In this embodiment, the element facing parallel to the blood vessel wall receives only vertically reflected waves, and can prevent reception of other reflected waves. As a result, the S/N ratio is high, and the blood vessel diameter can be easily detected.

Hereinafter, a sixth embodiment of an ultrasonic measurement device and an ultrasonic measurement method according to the present invention will be described with reference to the drawings.
26 is a schematic cross-sectional view showing a blood vessel diameter measurement device and a blood vessel diameter measurement method according to this embodiment. This embodiment differs from the above-mentioned fifth embodiment in terms of the element section, and other configurations corresponding to those of the above-mentioned fifth embodiment are given the same reference numerals and their description will be omitted.

In the blood vessel diameter measurement device 1 in this embodiment, as shown in Fig. 26, the element section 13 has a plurality of elements 13B. The plurality of elements 13B have planar radiation detection element surfaces 13Ba. In the element section 13, the plurality of elements 13B are fixed to the backing section 14 so that the radiation detection element surfaces 13Ba are flush with each other. In this embodiment, no surface corresponding to the physical radiation detection surface 11 is formed.
In this embodiment, the multiple elements 13 B are driven with a delay, and are inclined as the element section 13 so that ultrasonic waves can be transmitted and received at a radiation angle corresponding to the radiation detection surface 11 .

In this embodiment, the delay drive of the multiple elements 13B is specifically configured to sequentially delay the emission timing from the element 13B located at the center of the element section 13 to the peripheral elements 13B, thereby enabling ultrasonic waves to be emitted radially.

As a result, the ultrasonic emission detection unit 10 in this embodiment can also transmit ultrasonic waves radially and receive vertical reflected waves RU with no phase change with sufficient strength.

In this embodiment, it is possible to achieve the same effect as the above-mentioned embodiment. In this embodiment, it is possible to achieve the effect that there is less attenuation at the acoustic lens interface, and the received strength of the reflected wave is improved compared to the case where an acoustic lens is used. In this embodiment, it is possible to achieve the effect that a thin configuration is possible because an acoustic lens is not used.

Hereinafter, a seventh embodiment of an ultrasonic measurement device and an ultrasonic measurement method according to the present invention will be described with reference to the drawings.
Fig. 31 is a schematic diagram showing a transmission state of the blood vessel diameter measurement device and blood vessel diameter measurement method of this embodiment. Fig. 32 is a schematic diagram showing a reception state of the blood vessel diameter measurement device and blood vessel diameter measurement method of this embodiment.
In this embodiment, the difference from the first to sixth embodiments described above is with respect to the acoustic lens unit, and the configurations corresponding to the other embodiments described above are denoted by the same reference numerals and the description thereof will be omitted. Note that in Figs. 31 and 32, illustrations of components other than the element unit 13 and the acoustic lens unit are omitted.

As shown in FIGS. 31 and 32, the blood vessel diameter measurement device 1 in this embodiment has a linear Fresnel lens 15F1 as an acoustic lens section.
The linear Fresnel lens 15F1 has a lens surface shaped to be divided into a plurality of areas corresponding to the radiation detection surface 11 of the acoustic lens 15. Like the acoustic lens 15, each lens surface is formed so as to refract ultrasonic waves at a predetermined angle.
In this embodiment, the linear Fresnel lens 15F1 has multiple lens surfaces that function as acoustic lens portions and are inclined so as to be able to transmit and receive ultrasonic waves at a radiation angle corresponding to the radiation detection surface 11. The linear Fresnel lens 15F1 can be formed so as to have a smaller thickness at the center and a larger thickness on the outside compared to the acoustic lens 15. The linear Fresnel lens 15F1 can have a smaller difference between the thickness at the center and the thickness on the outside compared to the acoustic lens 15.

In this embodiment, the same effects as those of the above-mentioned embodiment can be achieved. In this embodiment, by using the linear Fresnel lens 15F1, the difference in thickness between the outside and the center in the acoustic lens portion can be made smaller than that in the acoustic lens 15. This makes it possible to reduce the phase difference of ultrasonic waves between the outside and the center in the acoustic lens portion. Therefore, the accuracy and precision of the measurement value can be improved.
It can also be used as a lens with a curvature having a diameter smaller than the width dimension of the element portion 13 .

Furthermore, in the present invention, it is possible to individually select the individual configurations in each of the above-mentioned embodiments and implement them in combination.

(A1) A blood vessel diameter measurement device according to one aspect of the present invention,
an ultrasonic radiation detection unit having a radiation detection surface that transmits ultrasonic waves from a surface of a living body toward the inside of the living body and receives vertically reflected waves of the transmitted ultrasonic waves that are vertically reflected by a peripheral surface of a blood vessel inside the living body;
a control unit capable of determining a blood vessel diameter value inside the living body based on a difference between a distance from the radiation detection surface to a blood vessel wall surface on a body surface side, the difference being calculated from a difference in arrival times of the perpendicular reflected waves to the radiation detection surface, and a distance from the radiation detection surface to a blood vessel wall surface on a body deep side, and outputting the blood vessel diameter value;
Equipped with
The ultrasonic radiation detection unit transmits the ultrasonic waves radially so as to spread around in at least one direction.
It is possible.
(A2) The blood vessel diameter measurement device of the present invention comprises the steps of:
The control unit outputs a blood pressure estimated from the blood vessel diameter value.
It is possible.
(A3) The blood vessel diameter measurement device of the present invention comprises the steps of:
The ultrasonic radiation detection unit has a radiation detection surface having a curved surface shape that is a part of a cylindrical surface.
It is possible.
(A4) The blood vessel diameter measurement device of the present invention comprises the steps of:
The ultrasonic radiation detection unit includes:
an element portion having a planar radiation detection element surface;
an acoustic lens portion in contact with the radiation detection surface of the element portion and having the radiation detection surface in a curved shape that is a part of a cylindrical surface;
Equipped with
It is possible.
(A5) The blood vessel diameter measurement device of the present invention comprises the steps of:
The ultrasonic radiation detection unit includes:
an element portion having the radiation detection surface in a curved shape that is a part of a cylindrical surface;
It is possible.
(A6) The blood vessel diameter measurement device of the present invention comprises the steps of:
The ultrasonic radiation detection unit has a plurality of element units each having a planar radiation detection element surface,
The plurality of element units are arranged in an array inclined to each other so that the ultrasonic waves can be transmitted radially in at least one direction.
It is possible.
(A7) The blood vessel diameter measurement device of the present invention comprises the steps of:
The ultrasonic radiation detection unit has a plurality of element units each having a planar radiation detection element surface,
The control unit delays and drives the plurality of element units so as to transmit the ultrasonic waves radially in at least one direction.
It is possible.
(A8) The blood vessel diameter measurement device of the present invention comprises the steps of:
The ultrasonic radiation detection unit has a fixing unit that can be fixed to a living body surface near a blood vessel that is a measurement target.
It is possible.
(A9) A blood vessel diameter measuring method according to another aspect of the present invention comprises:
The radiation detection surface transmits ultrasonic waves from the surface of the living body toward the inside of the living body, and receives vertically reflected waves of the transmitted ultrasonic waves that are vertically reflected by the circumferential surface of a blood vessel inside the living body,
when determining a blood vessel diameter value inside the living body based on a difference between a distance from the radiation detection surface to a blood vessel wall surface on a body surface side and a distance from the radiation detection surface to a blood vessel wall surface on a body deep side, the difference being calculated based on an arrival time difference of the perpendicular reflected wave to the radiation detection surface,
The ultrasonic wave is emitted from the radiation detection surface in a radial manner spreading around in a direction along a blood vessel inside the living body.
It is possible.

The blood vessel diameter measurement device of the present invention has the above-mentioned (A1) configuration, so that even if the radiation detection surface of the ultrasound radiation detection unit is not parallel to the blood vessel wall, the ultrasound is emitted radially, so that measurement can be performed in a state where a vertical reflected wave perpendicularly reflected by the blood vessel wall is incident on the radiation detection surface in any of the radially inclined directions of the ultrasound, in particular, even if the radiation detection surface is inclined to the axial direction of the blood vessel, the ultrasound is emitted radially, so that measurement can be performed in a state where a vertical reflected wave perpendicularly reflected by the blood vessel wall is incident on the radiation detection surface in any of the radially inclined directions of the ultrasound.
This makes it possible to detect vertically reflected waves with sufficient intensity at the radiation detection surface that have no phase change and can be used to measure the blood vessel diameter. Therefore, even if the radiation detection surface and the blood vessel wall are not parallel to each other due to bodily movements of the subject, it is possible to accurately calculate the difference between the distance from the radiation detection surface to the blood vessel wall surface on the body surface side and the distance from the radiation detection surface to the blood vessel wall surface deep inside the body, just as in the case where the radiation detection surface and the blood vessel wall are parallel, and maintain a state in which it is possible to accurately determine and output the blood vessel diameter value inside the living body.

The blood vessel diameter measuring device of the present invention has the above-mentioned (A1) and (A2) configuration, and by wearing the blood vessel diameter measuring device at all times, it becomes possible to continuously measure changes in the blood pressure and pulse rate of the subject.

In the blood vessel diameter measurement device of the present invention, in addition to the above (A1) or (A2), the configuration of (A3) allows ultrasonic waves to be emitted radially in the axial direction of the blood vessel from the radiation detection surface without having a scanning mechanism capable of emitting ultrasonic waves radially. Therefore, in any direction of the radially inclined ultrasonic waves, a vertically reflected wave perpendicularly reflected by the blood vessel wall can be made to enter the radiation detection surface while maintaining its phase unchanged, thereby making it possible to perform measurement.
Here, when the ultrasonic radiation detection section includes an element section, it is necessary to form the radiation detection element surface of the element section so that the radiation detection element surface becomes a radiation detection surface having a predetermined curved shape.
It is necessary to align the direction of curvature of the curved radiation detection surface with the scanning direction of the blood vessel, and to orient the ultrasonic radiation detection unit along the blood vessel so that it can be measured.

The blood vessel diameter measurement device of the present invention, in any one of (A1) to (A3) above, has the configuration of (A4) above, and by using a piezoelectric element having a known planar radiation detection element surface as an element part, and bonding an acoustic lens having a radiation detection surface formed with a predetermined curvature in one direction to this element part, it is possible to transmit ultrasonic waves radially in the axial direction of the blood vessel from the radiation detection surface of the acoustic lens. Therefore, it is possible to provide a blood vessel diameter measurement device that can output accurate blood vessel diameter values with a simple structure. Moreover, by setting the curvature of the acoustic lens in advance or changing the curvature of the acoustic lens, it is possible to easily control or change the angle at which ultrasonic waves transmitted from the radiation detection surface spread.
Here, the element section and the acoustic lens can be bonded to each other, formed as a single unit, or fixed in close contact with each other. In any state, it is necessary that the radiation detection element surface of the support section and one surface of the acoustic lens are in close contact with each other.

The blood vessel diameter measuring device of the present invention, in any of (A1) to (A3) above, has the configuration of (A5) above, so that the radiation detection element surface of the element itself forms the radiation detection surface. At the same time, by arranging the axis of the cylinder forming the cylindrical surface of the radiation detection surface so that it is parallel to the surface of the living body and perpendicular to the blood vessel, ultrasonic waves can be sent from the radiation detection surface to the blood vessel wall at different angles along the axis of the blood vessel. Furthermore, among the ultrasonic waves with different angles, there are waves at angles at which vertically reflected waves that are reflected perpendicularly from the blood vessel wall to the radiation detection surface and do not change in phase reach the radiation detection surface. Therefore, it is possible to receive vertically reflected waves with a sufficiently large S/N ratio, and maintain a state in which the blood vessel diameter value inside the living body can be accurately determined and output.

The blood vessel diameter measuring device of the present invention, in any of (A1) to (A3) above, has the configuration of (A6) above, so that the radiation detection element surfaces of the multiple elements directly form the radiation detection surface. Also, by arranging the radiation detection element surfaces of elements at predetermined positions in an array so as to form a predetermined angle, it is possible to radially emit ultrasonic waves from the radiation detection surface along the axial direction of the blood vessel as an ultrasonic radiation detection unit. Therefore, it is possible to provide a blood vessel diameter measuring device capable of outputting accurate blood vessel diameter values.

The blood vessel diameter measuring device of the present invention, in any of (A1) to (A3) above, has the configuration of (A7) above, so that the radiation detection element surfaces of the multiple elements directly form the radiation detection surface. In addition, the multiple elements can be delayed driven to emit ultrasonic waves inclined at a predetermined angle from elements in a predetermined position, so that ultrasonic waves can be emitted radially along the axial direction of the blood vessel. Therefore, it is possible to provide a blood vessel diameter measuring device that can output accurate blood vessel diameter values.

In any of the above (A1) to (A7), the blood vessel diameter measuring device of the present invention has the above configuration (A8), so that the blood vessel diameter measuring device can be maintained in a position where accurate measurements can be made with respect to the blood vessel. This allows the blood vessel diameter measuring device to continuously output accurate measurement values. In addition, the fixing part makes it easy to wear the blood vessel diameter measuring device at all times. By wearing the blood vessel diameter measuring device at all times, it becomes possible to continuously measure changes in the blood pressure and pulse rate of the subject. The fixing part allows the blood vessel diameter measuring device to continuously output accurate measurement values even when worn at all times.

The blood vessel diameter measuring method of the present invention has the above-mentioned (A9) configuration, so that even if the radiation detection surface of the device for measuring blood vessel diameter by ultrasound is not parallel to the blood vessel wall, measurement can be performed in a state where a vertical reflected wave perpendicularly reflected by the blood vessel wall is made incident on the radiation detection surface in any of the radially inclined directions of the ultrasound by radially transmitting the ultrasound. In particular, even if the radiation detection surface is inclined to the axial direction of the blood vessel, measurement can be performed in a state where a vertical reflected wave perpendicularly reflected by the blood vessel wall is made incident on the radiation detection surface in any of the radially inclined directions of the ultrasound by radially transmitting the ultrasound.
In the blood vessel diameter measuring method of the present invention, the phase does not change and the vertical reflected wave that can be used to measure the blood vessel diameter can be detected with sufficient intensity on the radiation detection surface. Therefore, even if the radiation detection surface and the blood vessel wall are not parallel to each other due to bodily movements of the subject to be measured, the difference between the distance from the radiation detection surface to the blood vessel wall surface on the body surface side and the distance from the radiation detection surface to the blood vessel wall surface deep inside the body can be accurately calculated in the same way as when the radiation detection surface and the blood vessel wall are parallel, and a state in which the blood vessel diameter value inside the living body can be accurately determined and output can be maintained.
Here, any one of the blood vessel diameter measurement devices (A1) to (A8) above can be used.

(B1) An ultrasonic measurement device according to one aspect of the present invention,
an ultrasonic radiation detection unit having a radiation detection surface that transmits ultrasonic waves toward a measurement object having an interface formed therein due to a difference in acoustic impedance, and receives a vertically reflected wave that is a result of the ultrasonic waves transmitted to the measurement object being vertically reflected at the interface;
A single element portion for transmitting and receiving ultrasonic waves;
an acoustic lens unit that transmits the ultrasonic waves emitted from the element unit radially in at least one direction and transmits the vertically reflected waves to the element unit;
having
It is characterized by:
(B2) The ultrasonic measuring device of the present invention comprises the above (B1),
the acoustic impedance of the element portion is greater than the acoustic impedance of the acoustic lens portion,
The acoustic impedance of the acoustic lens portion is greater than the acoustic impedance of the measurement object located on both sides of the interface.
It can be said that.
(B3) The ultrasonic measuring device of the present invention comprises the above (B1),
the interface is generally cylindrical;
the radiation detection surface is curved in a direction at least along an axis of the interface;
It is possible.
(B4) The ultrasonic measuring device of the present invention comprises the above (B1),
The ultrasonic radiation detection unit has a radiation detection surface having a curved surface shape that is a part of a cylindrical surface.
It is possible.
(B5) The ultrasonic measuring device of the present invention comprises the above (B1),
The element portion has a planar radiation detection element surface,
the acoustic lens portion is in contact with the radiation detection element surface of the element portion, and has the radiation detection surface having a curved shape that is a part of a cylindrical surface;
It is possible.
(B6) An ultrasonic measurement method according to another aspect of the present invention includes:
The radiation detection surface transmits ultrasonic waves from the surface of the measurement object toward the inside of the measurement object, the measurement object having a cylindrical interface formed therein due to a difference in acoustic impedance, and receives a vertically reflected wave that is perpendicular to the interface of the transmitted ultrasonic waves.
when determining a diameter dimension of the interface inside the measurement target based on a difference between a distance from the radiation detection surface to the interface on a surface side of the cylindrical interface and a distance from the radiation detection surface to the interface on a deeper side, the difference being calculated based on an arrival time difference of the perpendicular reflected wave to the radiation detection surface,
The ultrasonic wave is emitted from the radiation detection surface in a radial manner spreading around the periphery in a direction along an axis of the cylindrical interface.
It is possible.

The ultrasonic measurement device of the present invention has the above-mentioned (B1) configuration, which improves the accuracy of measuring the distance to the interface. Since there is no need to control multiple element parts simultaneously, it is possible to measure the shape of the interface with a simple configuration.

The ultrasonic measurement device of the present invention has the above-mentioned (B2) configuration, which can improve the accuracy of measuring the distance to the interface.

The ultrasonic measurement device of the present invention has the above-mentioned (B3) configuration, and by measuring the distance from the surface side to the deep side of the cylindrical interface, it is possible to easily and accurately measure the diameter dimension of the cylindrical interface.

The ultrasonic measurement device of the present invention has the above-mentioned (B4) configuration, and by measuring the distance from the surface side to the deep side of the cylindrical interface, it is possible to easily and accurately measure the diameter dimension of the cylindrical interface.

The ultrasonic measurement device of the present invention has the above-mentioned (B5) configuration, and by measuring the distance from the surface side to the deep side of the cylindrical interface, it is possible to easily and accurately measure the diameter of the cylindrical interface.

The ultrasonic measurement method of the present invention has the above-mentioned (B6) configuration, and by measuring the distance from the surface side to the deep side of the cylindrical interface, it is possible to easily and accurately measure the diameter dimension of the cylindrical interface.

The following describes an embodiment of the present invention.

Here, we will explain a test for measuring blood vessel diameter as a specific example of the blood vessel diameter measuring device and blood vessel diameter measuring method of the present invention.

<Experimental Example 1>
In Experimental Example 1, a simulated blood vessel made of a silicone rubber tube with a diameter of 3 mm (outer diameter 5 mm, inner diameter 3 mm) was prepared and placed in water. At the same time, a liquid simulating blood was circulated through the simulated blood vessel. This allowed the propagation speed of the ultrasonic waves to match the conditions inside the human body. In addition, the simulated blood vessel was tilted with respect to the element surface, and this was measured using a blood vessel diameter measuring device.
Here, an ultrasonic radiation detection unit using an acoustic lens was fabricated as shown in Figures 8 to 12. The specifications of the ultrasonic radiation detection unit are shown below.

Element size (element surface size): 4 mm x 5 mm
Element: PZT element Element thickness: 0.3 mm
Element drive energy: 100 μJ
Transmitted ultrasonic frequency: 12MHz

Distance between element and simulated blood vessel (front surface of tube outer diameter): 4.5 mm
Curvature of acoustic lens: R6mm
Acoustic lens: Acrylic resin Acoustic lens end thickness: 0.5 mm

The reflected waves from the vascular wall surface D2 and the vascular wall surface D3 shown in Figure 5 were measured. As a measurement result of the vascular wall surface D2, the angle dependence of the vertical reflected wave RU2 is shown in Figure 27. In addition, the angle dependence of the value of the vascular diameter d extending from the vascular wall surface D2 and the vascular wall surface D3 is shown in Figure 28.

The results shown in Figures 27 and 28 show that when the inclination of the blood vessel is within a range of ±6°, reflections of sufficient strength can be detected and accurate blood vessel diameter values can be obtained.

<Experimental Example 2>
In Experimental Example 2, measurements were carried out in the same manner as in Experimental Example 1, except that no acoustic lens was used and only a PZT element having a flat element surface was used.

As a measurement result of the vascular wall surface D2, the angle dependence of the vertical reflected wave RU2 is shown in Figure 29. Also, the angle dependence of the value of the vascular diameter d extending from the vascular wall surface D2 and the vascular wall surface D3 is shown in Figure 30.

The results shown in Figures 29 and 30 show that with a planar element, reflections of sufficient strength can only be detected when the inclination of the blood vessel is within a range of approximately ±1.5°, and accurate blood vessel diameter values cannot be obtained.

1...Blood vessel diameter measuring device (ultrasonic measuring device)
2... Case 3... Solid gel 10... Ultrasound radiation detection section 11... Radiation detection surface 13... Element section 13a... Radiation detection element surface 14... Backing section 15... Acoustic lens (acoustic lens section)
15F1...Linear Fresnel lens (acoustic lens part)
20...Control unit 30...Fixed unit 4+D...Blood vessel D1 to D4...Blood vessel wall RU, RU1 to RU4...Vertical reflected wave

Claims (19)

an ultrasonic radiation detection unit having a radiation detection surface that transmits ultrasonic waves toward a measurement target having an interface inside which an acoustic impedance difference exists, and receives vertically reflected waves of the ultrasonic waves transmitted to the measurement target and vertically reflected at the interface;
The ultrasonic radiation detection unit radially transmits the ultrasonic wave.
1. An ultrasonic measuring device comprising: the interface is generally cylindrical;
the radiation detection surface is curved in a direction at least along an axis of the interface;
2. The ultrasonic measuring device according to claim 1. The ultrasonic radiation detection unit has a radiation detection surface having a curved surface shape that is a part of a cylindrical surface.
3. The ultrasonic measuring device according to claim 2. The ultrasonic radiation detection unit has a radiation detection surface having a curved shape that is a part of a sphere.
3. The ultrasonic measuring device according to claim 2. The ultrasonic radiation detection unit includes an element unit that transmits and receives the ultrasonic waves,
an acoustic lens unit that transmits the radial ultrasonic wave toward the interface and transmits the received vertical reflected wave to the element unit;
having
2. The ultrasonic measuring device according to claim 1. the interface is generally cylindrical;
the acoustic lens portion has the radiation detection surface,
the radiation detection surface is curved in a direction at least along an axis of the interface;
6. The ultrasonic measuring device according to claim 5. The radiation detection surface is a curved surface that is a part of a cylindrical surface.
7. The ultrasonic measuring device according to claim 6. The radiation detection surface has a curved shape that is a part of a sphere.
7. The ultrasonic measuring device according to claim 6. The element portion has a planar radiation detection element surface,
The acoustic lens portion is in contact with the radiation detection element surface.
6. The ultrasonic measuring device according to claim 5. The element portion is composed of a single element.
6. The ultrasonic measuring device according to claim 5. the acoustic impedance of the element portion is greater than the acoustic impedance of the acoustic lens portion,
The acoustic impedance of the acoustic lens portion is greater than the acoustic impedance of the measurement object located on both sides of the interface.
6. The ultrasonic measuring device according to claim 5. The ultrasonic radiation detection unit has a plurality of element units that transmit and receive the ultrasonic waves.
2. The ultrasonic measuring device according to claim 1. The ultrasonic radiation detection unit transmits ultrasonic waves to a measurement target having an interface having an internal acoustic impedance difference, and receives a vertically reflected wave of the transmitted ultrasonic waves perpendicularly reflected at the interface to determine a distance from the ultrasonic radiation detection unit to the interface.
The ultrasonic radiation detection unit radially transmits the ultrasonic wave.
2. An ultrasonic measurement method comprising: the interface is generally cylindrical;
The ultrasonic wave is transmitted radially in at least a direction along an axis of the interface.
14. The ultrasonic measurement method according to claim 13. The ultrasonic radiation detection unit receives the vertical reflected wave on a radiation detection surface,
determining a distance from the radiation detection surface to the interface;
15. The ultrasonic measurement method according to claim 14. determining a diameter of the interface based on a difference between a distance from the radiation detection surface to the interface on a surface side of the cylindrical interface and a distance from the radiation detection surface to the interface on a deeper side of the cylindrical interface, based on a difference in arrival times of the perpendicular reflected waves to the radiation detection surface;
16. The ultrasonic measurement method according to claim 15. The ultrasonic radiation detection unit includes an element unit that transmits and receives ultrasonic waves,
an acoustic lens unit that transmits the radial ultrasonic wave toward the interface and transmits the received vertical reflected wave to the element unit;
having
the acoustic impedance of the element portion is greater than the acoustic impedance of the acoustic lens portion,
The acoustic impedance of the acoustic lens portion is greater than the acoustic impedance of the measurement object located on both sides of the interface.
16. The ultrasonic measurement method according to claim 15. The ultrasonic wave is emitted from the radiation detection surface in a radially expanding manner in a curved surface shape that is a part of a cylindrical surface.
18. The ultrasonic measurement method according to claim 17. The ultrasonic wave is transmitted from the radiation detection surface in a radially expanding manner in a curved surface shape that is a part of a sphere.
18. The ultrasonic measurement method according to claim 17.

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