JP5723960B2 - Vascular function testing device - Google Patents

Description

  The present invention relates to a medical vascular function inspection apparatus, and more particularly to an inspection apparatus that diagnoses the state of vascular function based on various information measured by, for example, an ultrasonic sensor.

  In recent years, a method for diagnosing the state of vascular function has attracted attention as one means for early discovery of diseases such as arteriosclerosis. For example, in the vascular mechanical property measuring apparatus of Patent Document 1, a technique for measuring a blood flow velocity distribution in a blood vessel and calculating a shear velocity distribution, a viscosity distribution, and a shear stress from the measured blood flow velocity distribution is disclosed. Has been. Then, it has been proposed that the calculated viscosity distribution and shear stress distribution be an index value for diagnosing the state of vascular function. In addition, the subject's blood vessel diameter (the blood vessel diameter at rest) is measured in a resting state, and the blood vessel diameter is measured after the forearm is blocked and released for about 5 minutes. It is also known that the blood vessel diameter increase rate FMD calculated by the amount and the resting blood vessel diameter (= the expansion amount of the blood vessel diameter / the blood vessel diameter at rest × 100%) is used as an index value for diagnosing the state of the blood vessel function. ing. Furthermore, the blood vessel wall thickness, blood vessel wall stress, and the like are also used as index values for diagnosing the state of blood vessel function.

JP 2006-166974 A JP 2003-144395 A

  As described above, many index values for diagnosing the state of vascular function have been proposed. However, the optimum index value for diagnosing the state of vascular function has not been determined, and there is room for further improvement. It was.

  An object of the present invention is to provide a vascular function inspection device that can further improve the accuracy of diagnosing the state of vascular function in a vascular function inspection device that diagnoses the state of vascular function.

  On the other hand, the inventors, as a new index value for diagnosing the state of vascular function, the amount of vascular expansion obtained by continuously measuring the vascular diameter of the expanded blood vessel after release of the subject's ischemia It was discovered that the state of vascular function can be diagnosed more accurately than before by applying a value obtained by dividing the above by the wall thickness of the blood vessel (= the amount of expansion of the blood vessel diameter / the wall thickness of the blood vessel). Then, by organizing the data with the above index value and the index value obtained by dividing the blood vessel wall thickness by the blood vessel diameter (= blood vessel wall thickness / blood vessel diameter), as (blood vessel wall thickness / blood vessel diameter) increases, It was discovered that a state in which (the amount of expansion of the blood vessel diameter / the wall thickness of the blood vessel) is reduced is drawn. It was also discovered that the state of vascular function can be diagnosed with high accuracy by organizing data based on vascular shear stress and wall stress.

That is, in order to achieve such an object, the gist of the present invention is that (a) a shear stress calculation unit for calculating shear stress of blood flowing in a blood vessel, and (b) an action on the blood vessel wall of the blood vessel. and wall stress calculation unit for calculating a wall stress, or outside the proper range of the shear stress and wall stress at least one is set in advance each of the shear stress and wall stress calculated (c) (D) the shear stress corresponds to a response delay time from the change of the shear stress to the change of the wall stress. The time point that is set in advance is set as a reference time point, and the integrated value of the shear stress in a predetermined interval before the reference time point, the average shear stress value per heartbeat in the predetermined interval, Same as pulse Characterized in that the those that are either integrated or average value of the instantaneous values.

In this way, based on whether or not at least one of the calculated shear stress and wall stress is out of an appropriate range of the shear stress and wall stress set in advance, the vascular function is determined. Since the vascular function diagnostic unit for diagnosing abnormalities is provided, abnormalities in vascular functions can be easily diagnosed by calculating shear stress and wall stress. A blood vessel is provided with a compensation function so that shear stress and wall stress always fall within an appropriate range regardless of fluctuations in blood flow and blood pressure. For example, when the wall stress increases with an increase in blood pressure, the thickness of the blood vessel wall increases in order to keep the wall stress constant. For example, when the blood viscosity increases and the shear stress increases, the blood vessel diameter is expanded to reduce the shear rate in order to keep the shear stress constant. As described above, the shear stress and the wall stress are maintained in the normal range by the compensation function inherent to the blood vessel. However, when the compensation function is lost, the shear stress and the wall stress are out of the appropriate range. Therefore, by calculating the shear stress and the wall stress and sequentially diagnosing whether or not they are out of the proper range, it is accurately diagnosed whether or not the compensation function of the blood vessel is functioning normally. For example, if at least one of shear stress and wall stress is out of the proper range, the change over time is monitored successively, and the cause, treatment method, and treatment effect are comprehensively diagnosed. can do.
In general, the reaction of the vascular endothelium responds instantaneously to changes in blood flow, but nitric oxide NO is produced and diffuses into the intima to reach the smooth muscle, and the response is delayed until the smooth muscle is relaxed. It is known that time will occur. That is, a response delay time from the change in shear stress to the change in wall stress occurs. Therefore, in anticipation of the response delay time, a time point that is earlier than the wall stress calculation time by the response delay time is set as a reference time point, and blood vessels are measured based on shear stress at each measurement time point within a predetermined interval before the reference time point. By calculating the shear stress, which is a representative value when diagnosing the function, the blood vessel function can be diagnosed based on the shear stress and the wall stress having a correlation. Also, the shear stress, which is a representative value when diagnosing vascular function, is not an instantaneous value at a certain time point (for example, the reference time point), and is based on the shear stress at each measurement time point within a predetermined section with the reference time point as an end point. By using the value calculated as described above, the blood vessel function can be diagnosed based on the shear stress in consideration of the stimulus applied to the blood vessel wall on a regular basis .

  Preferably, the display device includes a display device that displays the calculated relationship between the shear stress and the wall stress in a two-dimensional graph, and the display device includes a region surrounded by the appropriate range of the shear stress and the wall stress. It is displayed in advance, and the calculation result showing the relationship between the calculated shear stress and wall stress and the relative position of the region are displayed. In this way, since the calculation results of the shear stress and wall stress and the relative positions of the regions are displayed, it is possible to easily diagnose whether or not the blood vessel function is normal. Specifically, if the relationship position indicated by shear stress and wall stress is within the region, the vascular function is diagnosed as normal, and if the relationship position is out of the region, an abnormality has occurred in the vascular function. Can be easily diagnosed.

  Preferably, the apparatus further includes a storage unit that sequentially stores the shear stress calculated by the shear stress calculation unit and the wall stress calculated by the wall stress calculation unit, and calculates the shear stress and wall stress. When the result is displayed on the display device, the calculation information of the shear stress and the wall stress calculated before the previous time stored in the storage unit is displayed in a distinguishable manner. In this way, it is possible to make a comparison with the calculation result before the previous time, and it is possible to confirm a change in blood vessel function over time. Therefore, for example, when either shear stress or wall stress deviates from the appropriate range, the treatment method, the effect of treatment, etc. are also determined based on whether or not the deviated state has changed to return to the appropriate range. Can be evaluated.

  Preferably, the shear stress is calculated based on a blood flow velocity distribution from a two-dimensional or three-dimensional Navier-Stokes equation stored in advance. In this way, an accurate shear stress is calculated, and a practical blood vessel function inspection device can be provided.

  Preferably, the wall stress is calculated based on blood pressure, blood vessel diameter, and blood vessel wall thickness. In this way, by measuring the blood pressure, the blood vessel diameter, and the wall thickness of the blood vessel, an accurate wall stress can be calculated, and a practical blood vessel function inspection device can be provided.

Preferably, (a) a shear stress calculation unit for calculating a shear stress of blood flowing in the blood vessel , (b) a wall stress calculation unit for calculating a wall stress acting on the blood vessel wall of the blood vessel , and (c A display device that displays the calculated relationship between the shear stress and the wall stress in a two-dimensional graph, and (d) the display device has an appropriate range set in advance for each of the shear stress and the wall stress. An enclosed area is displayed, and (e) a calculation result indicating a relationship between the calculated shear stress and wall stress and a relative position between the area and the area are displayed. In this way, the relationship between the calculated shear stress and wall stress and the relative position of the region are displayed on the display device, so it is easy to determine whether the vascular function is normal based on the relative position. Can be diagnosed. Specifically, if the relationship position indicated by shear stress and wall stress is within the region, the vascular function is diagnosed as normal, and if the relationship position is out of the region, an abnormality has occurred in the vascular function. Can be easily diagnosed.

  Preferably, (a) the ultrasonic probe that radiates the ultrasonic wave toward the blood vessel is a longitudinal ultrasonic array in which a plurality of ultrasonic oscillators are linearly arranged in the longitudinal direction of the blood vessel. A probe, and an orthogonal ultrasonic array probe in which a plurality of ultrasonic oscillators are linearly arranged orthogonal to the longitudinal direction of the blood vessel, and (b) the longitudinal super The blood flow velocity in the blood vessel is measured by ultrasonic waves from the ultrasonic array probe, and the blood vessel diameter and blood vessel wall thickness are measured by ultrasonic waves from the orthogonal ultrasonic array probe. In this way, the blood flow velocity measurement, the blood vessel diameter measurement, and the blood vessel wall thickness measurement can be performed in parallel using a commercially available ultrasonic probe. For example, by alternately operating the longitudinal ultrasonic array probe and the orthogonal ultrasonic array probe in a very short cycle, the blood flow velocity measurement, the blood vessel diameter measurement, and the blood vessel wall The thickness measurement can be performed in parallel.

  Preferably, (a) the ultrasonic probe that radiates the ultrasonic waves toward the blood vessel is a longitudinal ultrasonic array in which a plurality of ultrasonic oscillators are linearly arranged in the longitudinal direction of the blood vessel. (B) the longitudinal ultrasonic array probe includes an operation for measuring a blood flow velocity in the blood vessel, an operation for measuring the blood vessel diameter, and The operation for measuring the vessel wall thickness is alternately performed as time passes. In this way, the blood flow velocity measurement, the blood vessel diameter measurement, and the blood vessel wall thickness measurement can be performed in parallel using a commercially available ultrasonic probe. For example, the longitudinal ultrasonic array probe is extremely operated for measuring the blood flow velocity in the blood vessel, for measuring the blood vessel diameter, and for measuring the blood vessel wall thickness. Alternate in short cycles.

It is a figure showing the whole structure of the blood vessel function test | inspection apparatus which is one Example of this invention. It is a figure explaining the xyz-axis orthogonal coordinate axis for expressing the attitude | position with respect to the blood vessel of the ultrasonic probe used for the blood vessel function test | inspection apparatus of FIG. It is an enlarged view for demonstrating the multilayer film structure of the blood vessel which is a measuring object from which an ultrasonic wave is radiated | emitted from the ultrasonic probe of FIG. 3 is a time chart illustrating a change in blood vessel diameter (endothelium diameter) after release of ischemia measured by ultrasonic waves from the ultrasonic probe of FIG. 2. It is a functional block diagram explaining the principal part of the control function with which the vascular function test | inspection apparatus of FIG. 1 was equipped. The figure which shows the relationship between the value (function index value) which divided the expansion amount of the blood vessel measured by the blood vessel function test | inspection apparatus by wall thickness, and well-known FMD (= expansion amount / blood vessel diameter at rest x100%). It is. It is a figure which shows the relationship between the wall thickness of the blood vessel measured by the blood vessel function test | inspection apparatus, and a blood vessel diameter. It is a figure which shows the relationship between the function parameter | index value (expansion amount / wall thickness) measured by the blood vessel function test | inspection apparatus, and the property index value (wall thickness / blood vessel diameter). It is a figure which shows the relationship between FMD (amount of expansion / blood vessel diameter at rest × 100%) and a property index value (wall thickness / blood vessel diameter). It is a figure which shows the relationship between the function and the property index value measured by the blood vessel function test | inspection apparatus, and age. It is a figure which shows the relationship between FMD (amount of expansion / blood vessel diameter at rest × 100%) and age. It is a figure which shows the relationship between the function parameter | index value (expansion amount / wall thickness) measured by the blood vessel function test | inspection apparatus, and age. Control operation for diagnosing vascular function based on the index value by calculating the function index value and the property index value based on the main part of the control operation of the vascular function testing device (electronic control device), that is, the expansion amount after the release of vascular ischemia It is a flowchart for demonstrating. It is a functional block diagram explaining the principal part of the control function with which the vascular function test | inspection apparatus which is another Example of this invention was equipped. It is an image figure of the blood flow velocity distribution measured by the blood flow velocity distribution measurement part with which the blood vessel function test | inspection apparatus of FIG. 14 was equipped. It is a figure for demonstrating the code | symbol used for the type | formula used to calculate the blood flow velocity distribution measured by the blood flow velocity distribution measurement part with which the vascular function test | inspection apparatus of FIG. 14 was equipped. It is an image figure of the blood viscosity distribution calculated by the blood viscosity distribution calculation part with which the vascular function test | inspection apparatus of FIG. 14 was equipped. It is the figure which illustrated the state by which the space in the blood vessel from which the blood flow velocity distribution was measured with the ultrasonic wave from the ultrasonic probe of FIG. 2 was divided | segmented into the several sub area | region divided virtually. It is an image figure of the blood shear rate distribution calculated by the shear rate distribution calculation part with which the blood vessel function test | inspection apparatus of FIG. 14 was equipped. It is an image figure of the blood shear stress distribution calculated by the shear stress distribution calculation part with which the blood vessel function test | inspection apparatus of FIG. 14 was equipped. It is a figure showing the relationship between the shear rate and a viscosity in the case of measuring a healthy person. It is a figure showing the relationship between the blood vessel diameter of the blood vessel when the healthy person is measured, and the thickness of the blood vessel wall. It is an example of the two-dimensional graph which shows the relationship between the shear stress displayed on the monitor display apparatus of FIG. 14, and wall stress. FIG. 15 is a flowchart for explaining a main part of a control operation of the vascular function inspection device (electronic control device) of FIG. 14, that is, a control operation for diagnosing abnormal vascular function based on shear stress and wall stress. It is a figure which shows the change of the data at the time of normalizing a predetermined index value with shear stress.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following embodiments, the drawings are appropriately simplified or modified, and the dimensional ratios, shapes, and the like of the respective parts are not necessarily drawn accurately.

  FIG. 1 shows a blood flow velocity distribution in a blood vessel 20 located immediately below the skin 18 of the upper arm 16 of the living body 14 and the blood vessel 20 using the hybrid probe unit 12 held in the sensor holder 10. 2 is a diagram showing the overall configuration of a blood vessel function testing device 22 that measures the blood vessel diameter and wall thickness of the blood vessel and measures blood pressure using a cuff 21. FIG.

  The hybrid probe unit 12 functions as a sensor for detecting biological information related to the blood vessel 20, that is, a blood vessel parameter. The hybrid probe unit 12 has two rows of first short-axis ultrasonic array probes A and first parallel to each other. 2. An H-shaped probe comprising a short-axis ultrasonic array probe B and a long-axis ultrasonic array probe C connecting the central portions in the longitudinal direction on a flat probe surface 27. The ultrasonic probe 24 and a multi-axis drive device (positioning device) 26 for positioning the ultrasonic probe 24 are provided. The first short-axis ultrasonic array probe A, the second short-axis ultrasonic array probe B, and the long-axis ultrasonic array probe C are, for example, a large number of piezoelectric ceramics. The ultrasonic transducers (ultrasonic oscillators) a1 to an are linearly arranged to be configured in a longitudinal shape.

FIG. 2 is a diagram for explaining the x ₀ y ₀ z ₀ axis orthogonal coordinate axes used in this embodiment, and is parallel to the longitudinal direction of the first short axis ultrasonic array probe A and its first short axis. The direction that is located directly below the axial ultrasonic array probe A and passes through or near the blood vessel 20 is defined as the z ₀ axis, and is parallel to the longitudinal direction of the long axis ultrasonic array probe C and orthogonal to the z ₀ axis. The direction is the x ₀ axis, passes through the intersection of the longitudinal direction of the first short axis ultrasonic array probe A and the long direction of the long axis ultrasonic array probe C, and the x ₀ axis direction and z _0. The direction perpendicular to the axial direction is taken as the y ₀ axis. The ultrasonic probe 24 is translated by the multi-axis drive device 26 in the z ₀ axis direction and rotated around the y ₀ axis and the z ₀ axis.

As shown in FIG. 3, the blood vessel 20 that is, for example, the brachial artery has a three-layer structure including an intima L ₁ , a media L ₂ , and an adventitia L ₃ . Since the reflection of ultrasonic waves occurs at different parts of the acoustic impedance, the boundary surface between the blood in the blood vessel lumen and the intima L ₁ and the boundary surface between the media L ₂ and the outer membrane L ₃ are actually displayed in white. Organizations are displayed in black and white groups. Further, in the image, the boundary surface between the intima L ₁ and the blood appears, it measures the distance as vessel diameter d1.

  Returning to FIG. 1, the blood vessel function testing device 22 includes an electronic control device 28 including a so-called microcomputer having a CPU that processes an input signal in accordance with a program stored in the ROM in advance while using the temporary storage function of the RAM. , A monitor screen display device (display device) 30, an ultrasonic drive control circuit 32, and a three-axis drive motor control circuit 34. A drive signal is supplied from the ultrasonic drive control circuit 32 by the electronic control unit 28, and the first short axis ultrasonic array probe A and the second short axis ultrasonic array of the ultrasonic probe 24 of the hybrid probe unit 12 are used. Ultrasonic waves are emitted from the probe B and the long-axis ultrasonic array probe C, and the first short-axis ultrasonic array probe A and the second short-axis ultrasonic array probe B and An ultrasonic image under the skin 18 is generated by receiving the ultrasonic reflection signal detected by the long-axis ultrasonic array probe C and processing the ultrasonic reflection signal in the ultrasonic signal processing unit. Can be displayed on the monitor screen display device 30. The electronic control unit 28 receives an ultrasonic reflection signal in the ultrasonic signal processing unit, measures a blood vessel diameter d1, a wall thickness t of the blood vessel 20, a blood flow velocity distribution DS, and the like, which will be described later, and determines the state of the blood vessel function. It has a function of calculating an index value (to be described later) at the time of diagnosis and diagnosing the state of vascular function based on the index value.

  Here, the monitor screen display device 30 includes an ultrasonic image by the first short-axis ultrasonic array probe A, an ultrasonic image by the second short-axis ultrasonic array probe B, and a long-axis ultrasonic image. Ultrasonic images from the acoustic array probe C can be displayed in predetermined image display areas, respectively. Furthermore, these image display areas have a common vertical axis indicating the depth from the skin 18.

  Further, when evaluating the blood flow-dependent vasodilator response, the monitor screen display device 30 calculates the change over time of the blood vessel diameter d1 after the release from the blood vessel ischemia state, that is, the time-dependent expansion amount R of the blood vessel diameter d1. Display in time series.

  In addition, as described above, when the blood flow-dependent vasodilation reaction is evaluated and the ultrasound image of the blood vessel 20 is generated, the electronic probe 28 is set so that the ultrasound probe 24 is at a predetermined measurement position with respect to the blood vessel 20. Thus, the multi-axis drive device 26 supplied with the drive signal from the three-axis drive motor control circuit 34 is driven and positioned. The predetermined measurement position is a position where the first short-axis ultrasonic array probe A and the second short-axis ultrasonic array probe B are orthogonal to the blood vessel 20, and a long-axis super-position. This is a position where the acoustic wave array probe C is parallel to the blood vessel 20.

  The sensor holder 10 is in a state in which the blood vessel 20 located immediately below the skin 18 of the upper arm 16 of the living body 14 is lightly contacted at a desired position in the three-dimensional space, that is, a predetermined measurement position so as not to deform. The hybrid probe unit 12 is held in a desired posture. The ultrasonic probe 24 of the hybrid probe unit 12 is generally well-known between the end face of the ultrasonic probe 24 and the skin 18 in order to clarify an ultrasonic image by suppressing ultrasonic attenuation, reflection and scattering at the boundary surface. A coupling agent such as jelly is interposed. This jelly is a gel-like water-absorbing polymer containing water at a high rate, for example, agar, etc., and has a sufficiently higher specific impedance (= sound speed × density) than air to suppress attenuation of ultrasonic transmission / reception signals. Is. Further, instead of the jelly, a water bag in which water is confined in a resin bag, olive oil, glycerin, or the like can be used.

  The sensor holder 10 includes, for example, a magnet base 36 that is fixed to a desk, a pedestal, etc. by magnetic attraction, a unit fixture 38 to which the hybrid probe unit 12 is fixed, a magnet base 36 and a unit fixture 38. Connecting members 44, 45 having one end fixed and a spherically formed tip portion 42, and via these connecting members 44, 45, the magnet base 36 and the unit fixture 38 are connected and supported so as to be relatively movable. And a universal arm 40 that performs the operation. The universal arm 40 includes two links 46 and 47 that are rotatably connected to each other, and a distal end portion 42 of which one end of the links 46 and 47 is energized with a predetermined resistance. And the other ends of the links 46 and 47 are connected to each other so that they can rotate relative to each other. And a rotary joint portion 54 that is made relatively unrotatable by a fastening force obtained by fastening a male threaded fixing knob 52 screwed into a screw hole penetrating the connecting portion.

Multiaxis driving device 26, and z ₀ axis rotation (yawing) mechanism that is fixed to the unit fixing tool 38 to position the rotational position around z ₀ axis of the ultrasonic probe 24 by z ₀ axis rotation actuator , z ₀ by the shaft rotation actuator and z ₀ axis translation mechanism for positioning the z ₀ of the axial translation position of the ultrasonic probe 24, the rotational position around y ₀ axis of the ultrasonic probe 24 by y ₀ axis actuator And a y ₀ axis rotation mechanism for positioning the lens.

  In FIG. 1, the ultrasonic drive control circuit 32 is configured according to a command from the electronic control device 28, for example, a large number of ultrasonic transducers arranged in a line constituting the first short axis ultrasonic array probe A. Among the a1 to an, the ultrasonic transducer a1 at the end thereof, a beam that is simultaneously driven at a frequency of about 10 MHz while giving a predetermined phase difference to each of a certain number of ultrasonic transducer groups, for example, 15 a1 to a15 By forming driving, a converging ultrasonic beam is sequentially emitted toward the blood vessel 20 in the arrangement direction of the ultrasonic transducers, and the ultrasonic beams are scanned while being shifted one by one. The reflected wave for each emission is received and input to the electronic control unit 28.

The electronic control unit 28 synthesizes an image based on the reflected wave, generates a cross-sectional image (short axis image) or a vertical cross-sectional image (long axis image) of the blood vessel 20 under the skin 18, and displays the monitor screen. The information is displayed on the device (image display device) 30. Further, from the image, such as a blood vessel diameter (endothelial diameter) d1 is the diameter of the outer membrane diameter d2 or endothelium 111 is the diameter of the outer membrane L ₃ of the blood vessel 20 is measured. Further, in order to evaluate the vascular endothelial function, ischemia is performed by the cuff 21, and the expansion amount (change amount) R (= d1-da) of the blood vessel diameter d1 of the blood vessel 20 after the ischemia is released (where da is at rest). The blood vessel diameter d1) is continuously measured. In addition, ischemia is performed for a predetermined time (for example, about 5 minutes) from a state in which the subject is kept at rest. Measured.

  FIG. 4 is a time chart illustrating the change in blood vessel diameter (endothelium diameter) d1 after release of ischemia. In FIG. 4, the time point t1 represents the time when the ischemia is released, and it is shown that the blood vessel diameter d1 starts to expand from the time point t2, and the blood vessel diameter d1 reaches its maximum value dmax at the time point t3. Therefore, the expansion amount R of the blood vessel diameter d1 calculated by the electronic control unit 28 becomes maximum at the time point t3.

The electronic control unit 28 synthesizes an image based on the reflected wave, generates a cross-sectional image (short axis image) or a vertical cross-sectional image (long axis image) of the blood vessel 20 under the skin 18, and displays the monitor screen. Each of them can be displayed on the device (image display device) 30. Further, from the image, it measures the endothelial diameter (vessel diameter) d1 and the like is the diameter of the outer membrane diameter d2 and endothelium 111 is the diameter of the outer membrane L ₃ of the blood vessel 20, from above, of the vessel wall of the blood vessel 20 thickness The wall thickness t (= (d2−d1) / 2) is calculated.

  FIG. 5 is a functional block diagram for explaining a main part of the control function provided in the blood vessel function testing device 22. As shown in FIG. 5, the ultrasonic drive control circuit 32 includes an echo receiving unit 72 as an echo receiving unit, and the electronic control unit 28 includes a blood vessel diameter measuring unit 80 for measuring the blood vessel diameter d1, A blood vessel wall thickness measuring unit 84 for measuring the wall thickness t of the blood vessel 20, a blood vessel dilation amount measuring unit 82 for continuously measuring the amount of change (expansion amount) of the blood vessel diameter d1 after the release of blood vessel ischemia, and will be described later. A blood vessel function index value calculation unit 86 for calculating an index value for diagnosing the blood vessel function, a blood vessel function diagnosis unit 88 for diagnosing the state of the blood vessel function based on the index value calculated by the blood vessel function index value calculation unit 86, and a display A display control unit 90 as a control unit and a cuff pressure control unit 94 (blood pressure measurement unit 94) for controlling ischemia of the blood vessel 20 are provided.

  The echo receiver 72 receives the reflected wave of the ultrasonic beam from the ultrasonic probe 24 and supplies it to the electronic control unit 28. For example, the echo receiving unit 72 receives the reflected wave of the ultrasonic beam from the first short-axis ultrasonic array probe A and inputs it to the blood vessel diameter measuring unit 80 and the blood vessel wall thickness measuring unit 84.

  The blood vessel diameter measuring unit 80 synthesizes a blood vessel image based on the reflected wave of the ultrasonic beam from the first short-axis ultrasonic array probe A supplied from the echo receiving unit 72, and from the synthesized blood vessel image. 3, the outer membrane diameter d2 of the blood vessel 20 and the blood vessel diameter (endothelium diameter) d1 of the endothelium 111 under the skin 18 shown in FIG. 3 are measured.

  The blood vessel diameter measuring unit 80 continuously blocks the blood vessel 20 with the cuff 21 for a predetermined time (for example, about 5 minutes), and continuously increases the blood vessel diameter d1 of the dilated blood vessel that changes as shown in FIG. To measure. Then, the vascular dilation measuring unit 82 measures the vascular diameter change amount of the blood vessel 20 after the ischemia is released, specifically, the dilation amount R (=) of the vascular diameter d1 by measuring the vascular diameter d1 after the ischemia is released. d1-da) is measured (where da is the blood vessel diameter d1 at rest). The ischemia of the blood vessel 20 is controlled by the cuff pressure control unit 94, and the pressure of the cuff 21 is controlled using the pressure control valve 29. Specifically, the pressure control valve 29 is controlled so that the air pressure in the cuff 21 is controlled to a pressure that stops the blood flow of the blood vessel 20 during ischemia and the air in the cuff 21 is instantaneously discharged when ischemia is released. Be controlled.

  The blood vessel wall thickness measuring unit 84 synthesizes a blood vessel image based on the reflected wave of the ultrasonic beam from the first short-axis ultrasonic array probe A supplied from the echo receiving unit 72, and the synthesized blood vessel image. The wall thickness t of the blood vessel 20 is measured based on the outer membrane diameter d2 of the blood vessel 20 and the blood vessel diameter (endothelium diameter) d1 of the endothelium 111 under the skin 18 shown in FIG. Here, the wall thickness t of the blood vessel 20 is calculated by a dimensional difference t (= (d2−d1) / 2) between the outer membrane diameter d2 and the endothelial diameter d1 as shown in FIG. The blood vessel wall thickness measuring unit 84 can continuously measure the wall thickness t similarly to the blood vessel diameter measuring unit 80, and can also measure the wall thickness t at a predetermined time.

  The blood vessel function index value calculation unit 86 divides the expansion amount R of the blood vessel diameter d1 of the blood vessel 20 after the release of ischemia measured by the blood vessel diameter measurement unit 80, for example, by the wall thickness t measured by the blood vessel wall thickness measurement unit 84. The value X1 (= expansion amount R / wall thickness t) is output as a function index value X1 for diagnosing vascular function. The expansion amount R is, for example, the maximum value Rmax (= dmax−da) of the expansion amount R after ischemia is released, and the wall thickness t is, for example, the time when the expansion amount R of the blood vessel 20 is the maximum value Rmax. The wall index t is used as a representative value, and the function index value X1 is calculated based on each representative value.

  FIG. 6 shows the relationship between the function index value X1 obtained by dividing the expansion amount R of the blood vessel 20 by the wall thickness t and the known FMD (= expansion amount R / blood vessel diameter da × 100% at rest). . As shown in FIG. 6, it can be seen that the function index value X1 (= expansion amount R / wall thickness t) and FMD are in a correlation. When FMD is performed, the blood vessel diameter d1 swells due to relaxation of smooth muscle due to the production of nitric oxide NO. However, oxygen monoxide NO produced in the endothelial cells of the blood vessel 20 diffuses in the intima. Therefore, the wall thickness t is considered to be one of the factors that determine the diffusion time. Moreover, since it is also a factor which determines the quantity of the smooth muscle which responds to nitric oxide NO, it is thought that the function parameter | index value X1 and FMD have a predetermined correlation. Therefore, the function index value X1 also functions as an alternative index value for the known FMD.

  In addition, the blood vessel function index value calculation unit 86 outputs a value X2 obtained by dividing the wall thickness t by the blood vessel diameter d1 as a quality index value X2 (wall thickness t / blood vessel diameter d1) for evaluating the blood vessel function. The blood vessel diameter d1 is, for example, the blood vessel diameter d1 when the expansion amount R is the maximum value Rmax after the ischemia is released, that is, the maximum blood vessel diameter dmax, as a representative value. The characteristic index value X2 is calculated based on each representative value with the wall thickness t at the time when is the maximum value Rmax as a representative value. FIG. 7 is a diagram showing the relationship between the wall thickness t of the blood vessel 20 and the blood vessel diameter d1. As shown in FIG. 7, it is known that the wall thickness t and the blood vessel diameter d1 are substantially proportional. Accordingly, the relationship between the blood vessel diameter d1 and the wall thickness t is a proportional relationship as shown in FIG. 7 in a normal state, but for example, in the case of hypertension or kidney injury, the thickening of the blood vessel 20 proceeds and deviates from the above relationship. It will be. Therefore, when an abnormality occurs in the vascular function, the relationship of wall thickness t / blood vessel diameter d1 is expected to deviate from the normal range. The blood vessel diameter d1 tends to be larger in males than in females, but this sex difference can be eliminated by the quality index value X2 (wall thickness t / blood vessel diameter d1).

  Accordingly, the function index value X1 indicated by the expansion amount R / wall thickness t and the property index value X2 indicated by the wall thickness t / blood vessel diameter d1 are set as the function change index value and the property change index value, respectively. When the values are arranged in two axes, as shown in FIG. 8, the function index value X1 (= expansion amount R / wall thickness t) increases as the property index value X2 (= wall thickness t / blood vessel diameter d1) increases. A state in which is reduced is drawn. The reason why the function index value X1 is small as described above is that the increase amount of the wall thickness t is larger than the increase amount of the blood vessel diameter d1. If the vertical axis in FIG. 8 is changed to a known FMD (= expansion amount R / resting blood vessel diameter da × 100%), FIG. 9 is obtained. As shown in FIG. 9, the graph is unclear even compared to the graph of FIG. For example, as shown in FIG. 9, when (wall thickness t / blood vessel diameter d1) is large, (expansion amount R / blood vessel diameter d1) is a large value. Also from this, as a graph showing the state of functional change and physical change of the blood vessel 20, the function index value X1 (expansion amount R / wall thickness t) and the physical index value X2 (wall thickness t / blood vessel diameter) as shown in FIG. The relationship diagram with d1) is an effective index value for diagnosing the state of vascular function because the above-described tendency is observed.

  In addition, the blood vessel function index value calculation unit 86 calculates a function / material index value that combines both the function change (dilation amount R / wall thickness t) and the property change (wall thickness t / blood vessel diameter d1). Then, a function / material index value X3 [= index value X1 (dilation amount R / wall thickness t) / index value X2 (wall thickness t / blood vessel diameter d1)] obtained by dividing the function index value X1 by the physical index value X2 is calculated. . The function / organization index value X3 is a function change with respect to the structure change, and a decrease in (expansion amount R / wall thickness t) leads to a decrease in the function / material index value X3. Furthermore, by taking into account the change in the constitution (wall thickness t / blood vessel diameter d1), the function / integrity index value X3 is further reduced compared to the function index value X1. In the function / organism index value X3, when the denominator is the reciprocal (blood vessel diameter d1 / wall thickness t), it coincides with FMD (expansion amount R / blood vessel diameter d1 × 100%). In this case, as shown in FIG. 9, when wall thickening occurs, the FMD moves in a direction to be improved, so that the data includes a factor of variation.

  10-12 arrange | positions said each index value according to the test subject's age. Here, FIG. 10 shows the relationship between the function / material index value X3 [= (dilation amount R / wall thickness t) / (wall thickness t / blood vessel diameter d1)] and age, and FIG. 11 shows FMD ( The relationship between the expansion amount R / blood vessel diameter d1 × 100%) and age is shown, and FIG. 12 shows the relationship between the function index value X1 (expansion amount R / wall thickness t) and age. In addition, each data of each said figure calculates each index value based on the same measurement data, and is graphed. Moreover, in the data of FIGS. 10-12, what is filled in is the data measured from a healthy person, and what is not filled in is the cardiovascular disease, hypertension, diabetes, hyperlipidemia. Data measured from subjects with any of the symptoms or complications. As can be seen from any of FIGS. 10 to 12, as the age increases, the index value decreases (decreases vascular function).

  Looking at the relationship between FMD and age shown in FIG. 11, subjects with any of the above-mentioned diseases (indicated by triangles whose interiors are not filled) are concentrated at relatively low FMD values. In B and C, they are in a state of being separated from other subjects having illness. That is, it is difficult to distinguish from a healthy person (indicated by a triangle whose inside is filled). On the other hand, in the graph of FIG. 11, when the vertical axis is changed to the function index value X1 (expansion amount R / wall thickness t), it is as shown in FIG. In FIG. 12, the divergence between the subjects A, B, and C and subjects having other diseases is smaller than that in FIG. 11. Furthermore, in view of the relationship between the function / organism index value X3 and the age shown in FIG. 10, subjects A, B, and C are more subject to other subjects having a disease than the FIG. Is no longer a gap. In particular, in subjects A and B, the dissociation state with subjects having other diseases is greatly improved, and subjects A and B are no different from the subject group having diseases. As a result, by organizing the data according to the function index value X1 and the function / organization index value X3, the variation in data becomes smaller than that of the conventional FMD, so that it is easy to distinguish between healthy subjects and subjects with diseases. For example, it becomes easier to evaluate the state of the blood vessel function than in the past.

  Returning to FIG. 5, the vascular function diagnosis unit 88 diagnoses the state of the vascular function based on, for example, the relationship of FIG. 8 and the relationships of FIGS. 10 and 12. For example, according to the relationship shown in FIG. 8, as (wall thickness t / blood vessel diameter d1) increases, (dilation amount R / wall thickness t) tends to decrease. Whether or not it is within the range of the trend, and if it is out of the above range, the state of the vascular function is diagnosed based on how to deviate from the range, the amount of deviation from the range, or the like. Further, from FIG. 10, for example, whether or not the function / material index value X3 is lower than a reference value for age set in advance by experiments or the like, the state of the vascular function is diagnosed based on the function / material index value X3. Is done.

  The display control unit 90 causes the monitor screen display device 30 to display a two-dimensional graph indicating the relationship between the function index value X1 and the property index value X2 shown in FIG. In addition, the appropriate range that has been experimentally set in advance is also displayed at the same time, making it easier to diagnose the state of the vascular function. At this time, for example, data at the time of the previous measurement is stored in advance in the storage unit 92, and the relationship at the time of the previous measurement is displayed together, so that it is possible to check a change in blood vessel function from the time of the previous measurement. . This makes it possible to visually confirm, for example, the degree of recovery of vascular function and whether the current treatment method is correct.

  FIG. 13 shows the main part of the control operation of the blood vessel function testing device 22 (electronic control device 28), that is, the function index value X1, the property index value X2, and the function / material index value X3 based on the expansion amount R after the release of blood vessel ischemia. 5 is a flowchart for explaining a control operation for calculating vascular function and diagnosing vascular function based on each index value.

  First, in step SA1 (hereinafter, step is omitted) corresponding to the blood vessel diameter measuring unit 80, the blood vessel diameter da when the subject is at rest is measured in advance before ischemia. Next, in SA2 corresponding to the cuff pressure control unit 94, the blood vessel 20 is blocked for a predetermined time by increasing the cuff pressure from a resting state. In addition, the blood vessel 20 is blocked for about 5 minutes, for example. When a predetermined time elapses in a state where the blood vessel 20 is blocked, the air in the cuff 21 is discharged in SA3 corresponding to the cuff pressure control unit 94, thereby releasing the blood vessel 20 from being blocked. In SA4 corresponding to the blood vessel diameter measuring unit 80 and the blood vessel wall thickness measuring unit 84, the blood vessel diameter d1 and the wall thickness t are continuously measured simultaneously with the release of the ischemia. In addition, the said measurement is implemented only for the predetermined time (for example, about 60 second) preset, for example. In SA5 corresponding to the vascular function index value calculation unit 86, the maximum value Rmax of the vascular dilation amount calculated by the difference between the maximum value dmax of the vascular diameter d1 measured for a predetermined time and the vascular diameter da at rest. (= Dmax−da) is calculated. In SA6 corresponding to the vascular function index value calculation unit 86, the function index value X1 (= maximum value Rmax / wall thickness t) is calculated based on the maximum value Rmax of the vascular dilation amount calculated in SA5. Further, the property index value X2 (= wall thickness t / blood vessel diameter d1) is calculated, and the function / material index value X3 (= X1 / X2) is calculated based on the calculated function index value X1 and the property index value X2. Is done. As the representative value of the wall thickness t at this time, for example, the wall thickness t measured when the maximum value Rmax of the vascular dilation amount R is calculated is used. In SA7 corresponding to the vascular function diagnosis unit 88, the vascular function is diagnosed by comparison with an appropriate range set in advance based on the calculated index values (X1 to X3). At this time, in SA8 corresponding to the display control unit 90, the relationship between the function index value X1 and the property index value X2 is displayed on the monitor screen display device 30 as a two-dimensional graph, so that the state of the vascular function is visually confirmed. It becomes possible to confirm.

  As described above, according to the present embodiment, after the blood vessel ischemia is released, the wall R measured by the blood vessel wall thickness measuring unit 84 is an expansion amount R of the blood vessel diameter d1 continuously measured by the blood vessel diameter measuring unit 80. Since the value divided by the thickness t (expansion amount R / wall thickness t) is used as the function index value X1 for diagnosing the vascular function, the state of the vascular function can be diagnosed more accurately than before. For example, in the past, the state of vascular function was diagnosed based on an index value (FMD: dilation amount R / vascular diameter d1 × 100%) obtained by dividing the dilation amount R of the blood vessel after release of ischemia by the vascular diameter d1, Compared with the conventional index value (FMD), the function index value of the present invention is more suitable for diagnosing the state of the vascular function because it has a large change with respect to the change in vascular function. The above is because the change amount of the wall thickness t is larger than the change amount of the blood vessel diameter d1, so that the change of the blood vessel function is easily reflected.

  Further, according to the present embodiment, the blood vessel function index value calculation unit 86 further calculates the property index value X2 obtained by dividing the wall thickness t by the blood vessel diameter d1, and the relationship between the function index value X1 and the property index value X2 is obtained. Based on this, vascular function is diagnosed. In this way, since the function index value X1 tends to decrease as the quality index value X2 increases, the state of the vascular function can be accurately diagnosed based on the above tendency. For example, when the measurement result deviates from the above tendency, an abnormality in vascular function is diagnosed based on the deviation or degree of deviation.

  Further, according to the present embodiment, the vascular function index value calculation unit 86 further calculates a value obtained by dividing the function index value X1 by the property index value X2 as the function / material index value X3, and the function / material index value X3. The vascular function is diagnosed based on the above. In this way, by calculating the function / material index value X3, the variation in data can be further suppressed, and the state of the vascular function can be diagnosed more accurately.

  Next, a blood vessel function testing device 95 according to another embodiment of the present invention will be described. In the following description, parts common to those in the above-described embodiment are denoted by the same reference numerals and description thereof is omitted.

  In FIG. 1, in addition to the above-described function, the electronic control unit 28 percutaneously enters an ultrasonic wave from the long-axis ultrasonic array probe C toward the blood vessel 20 in the living body 14, and The blood flow velocity distribution DS is measured non-invasively with sound waves. Then, the viscosity distribution DV and shear rate distribution DSR of the blood in the blood vessel 20 are calculated from the blood flow velocity distribution DS, and the shear stress distribution DSS is further calculated based on the viscosity distribution DV and the shear rate distribution DSR.

  Further, the electronic control unit 28 measures the blood pressure value by the oscillometric method using the cuff 21 wound around the upper arm. That is, for example, the pressure of the cuff 21 detected by the pressure sensor 23 is first increased to a hemostatic pressure higher than the systolic blood pressure (maximum blood pressure value) of the measurement subject using the pump 25 and the pressure control valve 29. Later, the pressure is gradually reduced at a predetermined step-down speed, and in the pressure drop process by the cuff 21, a pressure oscillation wave, that is, a pulse wave generated in synchronization with the heartbeat is extracted, and an inflection point of an envelope that connects the pulse wave amplitudes, that is, The pressure of the cuff 21 corresponding to the maximum value of the pulse wave amplitude difference is determined as the systolic blood pressure value SBP and the diastolic blood pressure value DBP. Further, the pressure indicating the maximum value of the pulse wave amplitude is determined as the average blood pressure value MBP.

  FIG. 14 is a functional block diagram for explaining the main part of the control function provided in the blood vessel function testing device 95 according to another embodiment of the present invention. Since the mechanical configuration is the same as that of the above-described embodiment, the description thereof is omitted. Further, the functions of the blood vessel diameter measuring unit 80 and the blood vessel wall thickness measuring unit 84 are basically the same as those in the above-described embodiment, and thus description thereof is omitted.

The echo receiver 72 receives the reflected wave of the ultrasonic beam from the ultrasonic probe 24 and supplies it to the electronic control unit 28. For example, the echo receiving unit 72 receives the reflected wave of the ultrasonic beam from the first short-axis ultrasonic array probe A and inputs it to the blood vessel diameter measuring unit 80 and the blood vessel wall thickness measuring unit 84. Further, the echo receiving unit 72 receives the reflected wave of the ultrasonic beam from the long-axis ultrasonic array probe C and inputs it to the blood flow velocity distribution measuring unit 100.

The blood flow velocity distribution measuring unit 100 creates a tomographic image using the ultrasonic scattered wave (reflected wave) received by the long-axis ultrasonic array probe C of the ultrasonic probe 24 and identifies the position of the blood vessel 20. At the same time, a two-dimensional velocity vector distribution in the two-dimensional fault plane is obtained. In this embodiment, the obtained velocity vector distribution may be two-dimensional or three-dimensional, but in order to perform simple processing, the two-dimensional velocity vector distribution is obtained, and the blood flow velocity distribution measuring unit 100 The dimensional velocity vector distribution is a blood flow velocity distribution DS. For example, the blood flow velocity distribution DS at a certain moment is shown by a solid line L01 shown in the image diagram of FIG. Here, the two-dimensional velocity vector distribution or the three-dimensional velocity vector distribution uses, for example, two ultrasonic tomographic images or three-dimensional volume images that are temporally continuous at a certain time interval to determine the movement amount of blood cells. It can be obtained by a correlation method and obtained by dividing the amount of movement by the time interval between two images. As another example, the blood flow velocity distribution measuring unit 100 obtains a velocity component in the ultrasonic radiation direction, which is one velocity component of a two-dimensional velocity vector, by a method similar to the well-known color Doppler method, and is orthogonal thereto. The other two-dimensional velocity vector distribution can also be obtained by using the non-compressed condition in the fluid dynamics represented by the following formula (1) stored in advance. In this way, the blood flow velocity distribution measuring unit 100 percutaneously enters the ultrasonic wave toward the blood vessel 20 in the living body 14 and measures the blood flow velocity distribution DS noninvasively. For confirmation, when the blood flow velocity distribution measuring unit 100 measures the blood flow velocity distribution DS, the ultrasonic probe 24 is positioned with respect to the blood vessel 20 so as to be at the predetermined measurement position. It is done. As shown in FIG. 16, “x” in the following equation (1) represents a position in a direction orthogonal to the ultrasonic beam axis, and “y” represents a position in the ultrasonic beam axis direction (ultrasonic radiation direction). Represent. “U” represents a velocity component in the x direction, and “v” represents a velocity component in the ultrasonic beam axis direction, that is, a velocity component in the y direction.

  The blood flow velocity distribution measuring means 100 can measure the blood flow velocity distribution DS instantaneously at a desired point in time, or can continuously perform the measurement according to the passage of time.

The blood viscosity distribution calculation unit 102 calculates the blood flow velocity distribution measured by the blood flow velocity distribution measurement unit 100 from a two-dimensional Navier-Stokes equation stored in advance by the following equations (2) and (3). Based on the DS, the blood viscosity distribution (blood viscosity distribution) DV in the blood vessel 20 to be measured is calculated. For example, the blood viscosity distribution DV at a certain moment is shown by a solid line L02 shown in the image diagram of FIG. 17 because of the non-Newtonian characteristics of blood. Further, the blood viscosity distribution calculation unit 102 calculates an average value of the blood viscosity μ from the blood viscosity distribution DV so that the blood viscosity μ can be grasped quantitatively. When the blood flow velocity distribution DS is a three-dimensional velocity vector distribution, a three-dimensional Navier-Stokes equation is used for calculating the viscosity distribution DV.

  Here, x, y, u, v in the above equations (2) and (3) are the same as those in the above equation (1), “t” is time, “p” is pressure, and “ρ” is The density of blood, “ν”, represents kinematic viscosity (also referred to as “kinematic viscosity”). Further, the kinematic viscosity ν is calculated by the above formula (4) when the blood viscosity (also referred to as “viscosity”) is “μ”. The kinematic viscosity ν can be obtained from the above formula (5) derived from the above formula (2) and the above formula (3) by eliminating the term of the pressure “p” included in the formula by the differential operation. it can. “Ξ” in the equation (5) is the vorticity, calculated by the above equation (6), and defined from only the velocity vector component as can be seen from the equation (6).

  When calculating the blood viscosity distribution DV based on the blood flow velocity distribution DS, the blood viscosity distribution calculation unit 102 assumes that the blood is incompressible, and the space in the blood vessel 20 as shown in FIG. Is subdivided into a plurality of sub-regions 130, and the blood density ρ and viscosity μ are constant in the sub-region 130, and the Navier-Stokes equations are calculated for each sub-region 130. Apply. Then, the blood viscosity distribution DV is calculated by integrating the blood viscosity μ calculated for each sub-region 130.

The shear rate distribution calculation unit 104 calculates a shear rate distribution (blood shear rate distribution) DSR of blood in the blood vessel 20 to be measured based on the blood flow rate distribution DS measured by the blood flow rate distribution measurement unit 100. Specifically, the shear velocity distribution calculation unit 104 obtains a two-dimensional strain velocity tensor based on the blood flow velocity distribution DS (two-dimensional velocity vector distribution), and the flow having the direction of the two-dimensional velocity vector as a tangential direction. A direction perpendicular to the line is approximated as a normal direction of the blood vessel 20, and the two-dimensional strain rate component is subjected to rotational coordinate conversion using the approximated normal direction of the blood vessel 20 as a base axis (arrow AR1 in FIG. 16). The shear component e _xy0 obtained by (see) is extracted as the shear rate SR, and the blood shear rate distribution DSR is calculated. If the blood shear rate distribution DSR at a certain moment is illustrated as an example, the blood shear rate distribution DSR is as indicated by a solid line L03 shown in the image diagram of FIG. Then, the shear rate distribution calculating unit 104 calculates an average value of the blood shear rate SR from the blood shear rate distribution DSR so that the blood shear rate (blood shear rate) SR can be quantitatively grasped. The shear component e _xy0 is expressed by the following formula (7) and is stored in advance in the following formula (7) shear rate distribution calculation unit 104. When the blood flow velocity distribution DS is a three-dimensional velocity vector distribution, a three-dimensional strain velocity tensor is used for calculating the blood shear velocity distribution DSR. Further, x ₀ , y ₀ , u ₀ , v _{0 in the following} equation (7) is a rotational coordinate transformation of x, y, u, v in the above equation (1) (see arrow AR1 in FIG. 16), 2 and 16, the y ₀ axis coincides with the normal direction of the blood vessel wall, and the x ₀ axis coincides with the longitudinal (long axis) direction of the blood vessel 20. The y axis coincides with the ultrasonic beam axis direction, and the x axis coincides with the orthogonal direction of the ultrasonic beam axis. U ₀ represents a velocity component in the x ₀ direction, and v ₀ represents a velocity component in the y ₀ direction.

When calculating the blood shear rate distribution DSR based on the blood flow rate distribution DS, the shear rate distribution calculation unit 104 is similar to the case of calculating the blood viscosity distribution DV as shown in FIG. The space is divided into a plurality of virtually subdivided sub-regions 130, and the equation (7) is applied to each sub-region 130 to calculate the shear component e _xy as the blood shear rate SR for each sub-region 130. To do. Then, the blood shear rate distribution DSR is calculated by integrating the blood shear rate SR (e _xy ) calculated for each sub-region 130.

  The shear stress distribution calculation unit 106 stores in advance a Newtonian viscosity law expressed by the following equation (8), and based on the blood viscosity distribution DV and the blood shear rate distribution DSR based on the Newtonian viscosity law. Blood shear stress distribution (blood shear stress distribution) DSS is calculated. In calculating the blood shear stress distribution DSS, the average value of the blood viscosity μ may be used instead of the blood viscosity distribution DV. If blood shear stress distribution DSS at a certain moment is illustrated as an example, the blood shear stress distribution DSS is as shown by a solid line L04 in the image diagram of FIG. Then, the shear stress distribution calculation unit 106 can quantitatively grasp the shear stress distribution (blood shear stress) DSS of the blood, and the average value SS of the blood shear stress at each measurement time point from the blood shear stress distribution DSS. (Hereinafter referred to as shear stress SS) is calculated.

  Furthermore, the shear stress distribution calculation unit 106 calculates a shear stress SS1 that is a representative value when diagnosing a vascular function based on the shear stress SS at each measurement time point. The representative value SS1 of the shear stress SS (shear stress SS1) is a point in time that goes back a preset time corresponding to a response delay time until the wall stress WS described later that occurs with the change of the shear stress SS is reached. As a reference time. That is, the shear stress SS1 is calculated with a time point that is earlier than a preset response delay time from the time of wall stress calculation as a reference time point. In the FMD, a large increase in blood flow occurs immediately after the release of ischemia, and the blood flow gradually decreases. At that time, the reaction of the vascular endothelium responds instantaneously to changes in blood flow. It is confirmed that a delay occurs until the smooth muscle is relaxed by diffusing into the intima and reaching the smooth muscle. is there. That is, the shear stress SS1 calculated at the reference time is correlated with the wall stress WS calculated after the response delay time has elapsed from the reference time, and the shear stress SS1 and the wall stress WS are set as representative values. Thus, the diagnosis of vascular function is accurate. The response delay time is experimentally set to, for example, about 20 to 30 seconds, or about 20 to 30 heartbeats.

Further, the shear stress SS1 that is a representative value calculated at the reference time point is an integrated value of the shear stress SS at each measurement time point within a predetermined interval up to the reference time point, per heart beat within a predetermined interval before the reference time point. The average shear stress value, or an integral value or an average value of instantaneous values synchronized with the pulse within a predetermined interval up to the reference time point. That is, the shear stress SS1 that is a representative value is calculated based on the shear stress SS calculated for each measurement time point within a predetermined section that is further back from the reference time point. The predetermined section is set to a period of about 20 heartbeats, for example, retroactively from the reference time point, that is, a period of about 20 heartbeats with the reference time point as an end point. As described above, the shear stress SS1 as a representative value is not calculated as an instantaneous value at a certain time point (specifically, a reference time point), but is calculated based on the shear stress SS sequentially calculated within a predetermined section. This is because the shear stress SS in consideration of the stimulus applied to the blood vessel wall on a regular basis is suitable for diagnosing the blood vessel function.

  When calculating the blood shear stress distribution DSS based on the blood viscosity distribution DV and the blood shear rate distribution DSR, the shear stress distribution calculating unit 106 calculates the blood viscosity distribution DV and the blood shear rate distribution DSR. Similarly, as shown in FIG. 18, the space in the blood vessel 20 is divided into a plurality of virtually subdivided sub-regions 130, and the blood viscosity μ obtained for each sub-region 130 according to the Newtonian viscosity law equation. The blood shear stress is calculated for each sub-region 130 by multiplying the blood shear rate by the blood shear rate. Then, the blood shear stress distribution DSS is calculated by integrating the blood shear stress calculated for each sub-region 130. Note that FIG. 15, FIG. 17, FIG. 19, and FIG. 20 are all image diagrams and do not necessarily match the actual distribution diagrams. 19 and 20 are expressed based on the absolute value of the blood shear rate distribution DSR, which is the difference result of the blood flow rate distribution DS, in the coordinate systems of those drawings.

  The blood pressure measurement unit 95 measures the blood pressure value by the oscillometric method by controlling the air pressure of the cuff 21 wound around the upper arm. The blood pressure measurement unit 95 uses the well-known oscillometric method based on the change in the magnitude of the pulse wave obtained as the pressure vibration of the cuff 21 during the gradual change process of the compression pressure of the cuff 21 to obtain the patient's maximum blood pressure value SBP. The diastolic blood pressure DBP is measured. In the oscillometric method, for example, in the pressure drop process of the cuff 21, a pressure oscillation wave, that is, a pulse wave generated in synchronization with the heartbeat is extracted, and an inflection point of an envelope connecting the pulse wave amplitudes, that is, a difference in pulse wave amplitudes. The pressure of the cuff 21 corresponding to the maximum value is determined as the maximum blood pressure value SBP and the minimum blood pressure value DBP. Further, the pressure of the cuff 21 when the pulse wave amplitude reaches the maximum value is determined as the average blood pressure value MBP.

The wall stress calculation unit 122 stores a predetermined wall stress relational expression expressed by the following formula (9), and the blood vessel diameter (endothelium) measured by the blood vessel diameter measuring unit 80 from the wall stress relational expression. Based on the diameter d1, the wall thickness t of the blood vessel 20 calculated by the blood vessel wall thickness measuring unit 84, and the blood pressure value measured by the blood pressure measuring unit 95, the wall stress WS acting on the blood vessel wall of the blood vessel 20 is calculated. . Here, in calculating the wall stress WS, in this embodiment, the diastolic blood pressure value DBP is used as a representative value, and the wall stress WS is based on the blood vessel diameter d1 and the wall thickness t measured at the time of the diastolic blood pressure value DBP, that is, at the end of the diastole. Is calculated. Since the blood vessel diameter d1 has the minimum value at the end of the expansion period, the time when the blood vessel diameter d1 continuously measured by the blood vessel diameter measuring unit 80 during the predetermined period becomes the minimum value is expanded. As of the end of the term.

  The vascular function diagnosis unit 124 determines the wall stress WS and the shear stress based on the wall stress WS calculated by the wall stress calculation unit 98 and the representative value SS1 (shear stress SS1) of the shear stress calculated by the shear stress calculation unit 96. It is determined whether at least one of SS1 is out of an appropriate range set in advance. Shear stress and wall stress are effective index values for diagnosing vascular function, and are closely related to each other. For example, the shear stress SS1 varies depending on the increase / decrease of the flow rate in the blood vessel 20, the hematocrit, or the amount of protein. When the shear stress SS1 increases, the nitric oxide NO produced from the blood vessel cells increases and the blood vessel 20 expands. The compensation function functions so as to reduce the shear stress SS1. On the other hand, when the blood vessel 20 is expanded, the wall stress WS increases as can be seen from the equation (9). Then, in order to relieve the wall stress WS, the wall thickness t of the blood vessel 20 increases, and when the shear stress SS and the wall embedding WS are balanced, both numerical values are within an appropriate range. The stress increases and the state deviates from the appropriate range. Further, when NO is inactivated by oxidative stress or the like, the expansion of the blood vessel 20 is suppressed, so that the shear stress SS1 remains high. In this case, the peripheral vascular resistance is also high, and the blood vessel 20 is dilated by increasing blood pressure. Even in this state, the wall stress SS1 becomes high, so that the wall thickness t increases as an adaptive reaction (compensation function). In this transient state, both the shear stress SS1 and the wall stress WS are high. The transitional change is very slow and, for example, the equilibrium state is reached over a span of several weeks or months. Therefore, changes in the shear stress SS1 and the wall stress WS are sequentially calculated, and based on the calculation results, a deviation state such as a deviation width from an appropriate range and a recovery state such as a recovery time (days) from the deviation state are monitored. By comparing with the judgment reference value, the state of the vascular function is evaluated, and can be used, for example, as a means for early detection of arteriosclerosis.

  The vascular function diagnosis unit 124 determines whether or not the calculated wall stress WS is within the range of an upper limit value WShi to a minimum value WSlo that is an appropriate range of wall stress set in advance. Furthermore, the blood vessel function diagnosis unit 124 determines whether or not the calculated shear stress SS1 is within a range of upper limit values SShi to SSlo that are preset appropriate ranges of shear stress. When the wall stress WS is within the appropriate range of the wall stress and the shear stress SS1 is within the proper range of the shear stress, the vascular function diagnosis unit 124 diagnoses that the vascular function functions normally. On the other hand, when at least one of the wall stress WS and the shear stress SS1 is out of the appropriate range, the vascular function diagnosis unit 124 diagnoses that an abnormality has occurred in the vascular function.

  It should be noted that it is difficult to determine the cause of abnormality in the vascular function and the treatment policy for it only when at least one of the shear stress SS1 and the wall stress WS deviates from the appropriate range by one measurement. However, by sequentially calculating and comparing changes in the shear stress SS1 and the wall stress WS, it is possible to diagnose the cause of the abnormality, the treatment policy, the effect of the treatment, and the like. For example, when the shear stress SS1 deviates from the appropriate range, the state of recovery to the appropriate range, the recovery speed, the change in the corresponding wall stress WS, etc. The effect).

  Here, the appropriate ranges of the wall stress WS and the shear stress SS1 are experimentally obtained in advance. For example, the wall stress WS and the shear stress SS1 are measured a plurality of times for a plurality of healthy persons, and the average values are set as the reference wall stress WSave and the reference shear stress SSave. For the reference wall stress WSave and the reference shear stress SSave, for example, a value of + 10% is set as the upper limit value (WShi, SShi) of the appropriate range, and a value of -10% is set as the lower limit value (WSlo, SSlo) of the appropriate range. To do.

  FIG. 21 shows the relationship between the shear rate SR and the viscosity μ when a healthy person is measured. The solid line is a hyperbola approximated based on a plurality of measurement points shown in the figure. The shear stress is calculated by the product of the shear rate SR and the viscosity μ. Here, in the hyperbola, the shear stress is constant at any point, and the shear stress represented by this hyperbola corresponds to the above-described reference shear stress SSave.

  FIG. 22 shows the relationship between the blood vessel diameter d1 of the blood vessel 20 and the wall thickness t when a healthy person is measured. The solid line is an approximate line approximated by a linear function based on a plurality of measurement points shown in the figure. The reference wall stress SSave is set based on the approximate line and the blood pressure at that time (for example, the minimum blood pressure value DBP).

  As another method for setting an appropriate range, for example, a plurality of subjects can be measured, wall stress WS and shear stress SS1 can be measured, and the subjects can be set comprehensively in consideration of their health conditions. . In addition, the appropriate range may be changed according to, for example, age or sex.

  The display control unit 126 displays the calculated shear stress SS1 and wall stress WS as a two-dimensional graph on the monitor screen display device 30 by numerical display or graph display. For example, as shown in FIG. 23, the calculation result is displayed in a two-dimensional graph in which the horizontal axis is the shear stress SS1 (representative value) and the vertical axis is the wall stress WS. In the two-dimensional graph, the upper limit value SShi and the lower limit value SSlo of the appropriate range of shear stress indicated by the alternate long and short dash line are displayed, and the upper limit value WShi and the lower limit value WSlo of the appropriate range of the wall stress indicated by the alternate long and two short dashes line are displayed. ing. And the area | region S enclosed by the dashed-dotted line and the dashed-two dotted line, ie, the area | region S enclosed by the appropriate range of shear stress and wall stress, is displayed as an appropriate range of a healthy person. Therefore, when the relationship position indicated by the calculated shear stress SS1 and wall stress WS is within the region S, the blood vessel function is diagnosed as normal. On the other hand, when either one of the shear stress SS1 and the wall stress WS deviates from the appropriate range, the relationship position deviates from the region S, so that it is diagnosed that an abnormality has occurred in the vascular function. From the above, since the relative position between the calculation result and the region S is displayed, the diagnosis result of the blood vessel function diagnosis unit 124 can be easily determined via the monitor screen display device 30.

  In addition, the display control unit 126 includes a storage unit 128 as a storage unit that sequentially stores calculation results (shear stress SS1 and wall stress WS) for each subject, and stores the calculation results for each subject before the previous time. Yes. Then, the display control unit 126 displays the previous calculation result at the same time as the current calculation result. At this time, as shown in FIG. 23, for example, the calculation result before the previous time and the current calculation result are displayed with marks having different shapes so as to be distinguishable. In addition, arrows can be displayed according to the order of the calculation results so that changes in the calculation results over time can be confirmed. Also, if there are many measurement results, mark them with different shapes by dividing them into measurement results from the date of measurement one month ago, measurement results from one month ago to two months ago, measurement results before that, etc. You can also.

  As described above, when the previous calculation result of the subject is displayed, changes in the shear stress SS1 and the wall stress WS can be confirmed over time, so that it is possible to comprehensively diagnose the treatment method, the effect of the treatment, and the like. it can. For example, depending on whether the shear stress SS1 or the wall stress WS has deviated from the appropriate range or both have deviated, the treatment method is different, and the treatment method based on them is selected. In addition, the effect of treatment is determined based on whether the parameters (shear stress SS1, wall stress WS) deviating from the appropriate range have changed in a direction to return to the appropriate range, or have remained without returning. Can be confirmed. Further, in a state where one parameter (shear stress SS1 or wall stress WS) deviates from an appropriate range, the treatment method and the effect of treatment are diagnosed based on the change of the other parameter (wall stress WS or shear stress SS1). Sometimes. Thus, the changes in the shear stress SS1 and the wall stress WS are displayed over time, so that the state of deviation of the blood vessel function can be sequentially monitored, and the treatment method policy and the effect of the treatment can be evaluated.

  FIG. 24 is a diagram for explaining the main part of the control operation of the blood vessel function test device 95 (electronic control device 28), that is, the control operation for diagnosing abnormality of the blood vessel function of the blood vessel 20 based on the shear stress and the wall stress. It is a flowchart.

  First, in step SB1 (hereinafter, step is omitted) corresponding to the blood pressure measurement unit 95, blood pressure measurement by pressurization of the cuff 21 is performed. Next, in SB2 corresponding to the blood vessel diameter measuring unit 80 and the blood flow velocity distribution measuring unit 100, the blood vessel diameter d1, the outer membrane diameter d2 and the blood flow velocity distribution DS of the blood vessel 20 are in a predetermined period (for example, about 60 to 120 seconds). ) Is continuously measured and stored. Specifically, a tomographic image is created using the ultrasonic scattered wave (reflected wave) received by the long-axis ultrasonic array probe C of the ultrasonic probe 24, the position of the blood vessel 20 is identified, and the blood vessel diameter is identified. Simultaneously with measuring d1 and outer membrane diameter d2, a two-dimensional velocity vector distribution (blood flow velocity distribution DS) in the two-dimensional tomographic plane is measured and stored sequentially. Next, in SB3 corresponding to the wall stress calculation unit 122, the end of expansion period, which is the time when the wall stress WS is calculated, is determined. The end of diastole is the time when the blood vessel diameter d1 measured in SB2 becomes the minimum value after a lapse of a predetermined time (for example, 60 seconds or more) from the start of measurement. Note that the blood flow velocity distribution in which the shear stress SS corresponding to the wall stress WS at the end of the diastole is retroactive from the end of the diastole is set at the end of the diastole after a predetermined time from the start of measurement. This is because it is calculated based on the DS. Then, when the end diastole time point is determined by SB3, the blood vessel diameter d1 and the outer diameter measured at the end diastole time point determined by SB3 are determined in SB4 corresponding to the blood vessel diameter measuring unit 80 and the blood vessel wall thickness measuring unit 84. The membrane diameter d2 is determined as a representative value for calculating the wall stress, and the wall thickness t (= (d2-d1) / 2) of the blood vessel 20 is determined based on the blood vessel diameter d1 and the outer membrane diameter d2 at that time. Calculated. In SB5 corresponding to the wall stress calculation unit 122, at the end of diastole, based on the relational expression stored in advance, the minimum blood pressure value DBP measured in SB1 and the blood vessel diameter d1 determined in SB4, and the wall thickness t. The wall stress WS of the blood vessel 20 is calculated. The SB4 and SB5 correspond to the main part of the wall stress calculation unit 98.

  In addition, in SB6 corresponding to the shear rate distribution calculation unit 104 and the blood viscosity distribution calculation unit 102, a time point that is 20 seconds to 30 seconds (or 20 to 30 heartbeats) after the wall stress WS is calculated as a reference time point. Based on the blood flow velocity distribution DS at each measurement time point that has been measured and stored in advance, an interval of 20 heartbeats before the reference time point from the two-dimensional Navier-Stokes equation stored in advance (in other words, the reference time point Further, the viscosity distribution DS in the blood vessel 20 at each measurement time is calculated in a section for 20 heartbeats and a section for 20 heartbeats with the reference time as the end point. Furthermore, the blood flow velocity distribution DS at each measurement time point that has been measured and stored in advance, with a time point that is 20 seconds to 30 seconds (or 20 to 30 heartbeats) after the wall stress WS is calculated as a reference time point. Based on the above, the blood in the blood vessel 20 at each measurement time point in the interval for 20 heartbeats before the reference time point (the interval for 20 heartbeats, the interval for 20 heartbeats with the reference time point as the end point) A shear rate distribution (blood shear rate distribution) DSR is calculated.

  Then, in the SB 7 corresponding to the shear stress distribution calculation unit 106, each measurement for 20 heartbeats is performed based on the viscosity distribution DS and shear rate distribution DSR in the blood vessel 20 in the section for 20 heartbeats up to the calculated reference time point. A shear stress distribution DSS at a time point is calculated, and an average value SS (shear stress SS) of blood shear stress at each measurement time point for 20 heartbeats immediately before the reference time point is calculated from the calculated shear stress distribution DSS. Further, from the calculated shear stress SS for 20 heartbeats until each measurement time point, the integrated value of the shear stress in a predetermined section (20 heartbeats) before the reference time, and the average shear stress per heartbeat in the predetermined section. Either the integrated value or the average value of the value and the instantaneous value synchronized with the pulse in the predetermined section is calculated as the representative value SS1 of the shear stress SS. The SB2, SB6, and SB7 correspond to the main part of the shear stress calculation unit 96.

  In SB8 corresponding to the vascular function diagnosis unit 124, an abnormality in the vascular function of the blood vessel 20 is diagnosed based on the wall stress WS and shear stress SS1 (representative values) calculated in SB4 and SB7. Specifically, it is determined whether or not the wall stress WS is within a preset appropriate range (WShi to WSlo), and the shear stress SS1 is within a preset proper range (SShi to SSlo). It is determined whether or not there is. When both the wall stress WS and the shear stress SS1 are within an appropriate range, the blood vessel function is diagnosed as normal. On the other hand, when at least one of the wall stress WS and the shear stress SS1 is out of the appropriate range, it is diagnosed that an abnormality has occurred in the blood vessel function of the blood vessel 20.

  In SB9 corresponding to the display control unit 126, the diagnosis result of SB8 is displayed on the monitor image display device 30 as a message, a numerical value display, or a two-dimensional graph, and the wall stress WS and shear stress SS1 are within the appropriate ranges. The deviation status is displayed. Specifically, on the two-dimensional graph represented by the wall stress and the shear stress, the region S surrounded by the preset appropriate range of the wall stress WS and the shear stress SS1, and the calculated wall stress WS and the shear stress. A relative position with respect to the stress SS1 is displayed. Accordingly, when the displayed calculation result is within the region S, it is identified that the vascular function is in a normal state. On the other hand, when the calculation result is out of the region S, an abnormality has occurred in the vascular function (healthiness is Identified as lost). Furthermore, the change in blood vessel function can be determined by displaying the measurement results measured before the previous time.

  As described above, according to the present embodiment, whether or not at least one of the calculated shear stress SS1 and the wall stress WS has deviated from the appropriate ranges of the shear stress and the wall stress set in advance, respectively. Based on this, the blood vessel function diagnosis unit 124 for diagnosing a blood vessel function abnormality is provided. Therefore, the blood vessel function abnormality can be easily diagnosed by calculating the shear stress SS1 and the wall stress WS. The blood vessel 20 is provided with a compensation function so that the shear stress SS1 and the wall stress WS are always within an appropriate range regardless of changes in blood flow and blood pressure. For example, when the wall stress WS increases with an increase in blood pressure, the wall thickness t of the blood vessel 20 increases to keep the wall stress WS constant. For example, when the blood viscosity μ increases and the shear stress SS1 increases, the blood vessel diameter d1 is expanded to decrease the shear rate in order to keep the shear stress SS1 constant. As described above, the shear stress SS1 and the wall stress WS are maintained in the normal range by the compensation function inherent to the blood vessel 20. However, if the compensation function is lost, the shear stress SS1 and the wall stress WS are out of the appropriate range. Therefore, by calculating the shear stress SS1 and the wall stress WS and sequentially diagnosing whether or not they are outside the proper range, it is accurately diagnosed whether or not the compensation function of the blood vessel 20 is functioning normally. The For example, when at least one of the shear stress SS1 and the wall stress WS is out of the proper range, the change over time is further sequentially monitored, and the cause, treatment method, and effect of treatment are comprehensively monitored. Can be diagnosed. Further, it is considered that arteriosclerosis starts when the compensation function is lost, and can be used as a means for early detection of arteriosclerosis.

  In addition, according to this embodiment, the monitor image display device 30 that displays the relationship between the calculated shear stress SS1 and the wall stress WS in a two-dimensional graph is provided, and the monitor image display device 30 includes the shear stress SS1 and the wall stress WS. The region S surrounded by the appropriate range is displayed in advance, and the calculation result indicating the relationship between the calculated shear stress SS1 and the wall stress WS and the relative position of the region S are displayed. In this way, the calculation result of the shear stress SS1 and the wall stress WS and the relative position of the region S are displayed, so that it is possible to easily diagnose whether or not the vascular function is normal. Specifically, when the calculation result is within the region S, the vascular function is normally diagnosed, and when the calculation result is at a position outside the region S, it can be easily diagnosed that an abnormality has occurred in the vascular function. .

  In addition, according to the present embodiment, the storage unit 128 that sequentially stores the shear stress SS1 calculated by the shear stress calculation unit 96 and the wall stress WS calculated by the wall stress calculation unit 98 is provided. When displaying the calculation results of SS1 and wall stress WS on the monitor image display device 30, the calculation information of the shear stress SS1 and the wall stress WS calculated before the previous time stored in the storage unit 128 is displayed in a distinguishable manner. Is. In this way, it is possible to make a comparison with the calculation result before the previous time, and it is possible to confirm a change in blood vessel function over time. Therefore, for example, when either the shear stress SS1 or the wall stress WS deviates from the appropriate range, the treatment method, the effect of the treatment, or the like is based on whether or not the deviated state is changed in a direction to return to the appropriate range. Can also be evaluated.

  Further, according to the present embodiment, the shear stress SS1 is defined as a reference time point that is a predetermined time corresponding to a response delay time from the change of the shear stress SS to the change of the wall stress WS. Integral value of shear stress SS1 within a predetermined interval (20 heartbeat intervals) before the reference time, average shear stress value per heartbeat within the predetermined interval, integrated value or average value of instantaneous values synchronized with the pulse within the predetermined interval It is assumed that either. In general, the endothelial reaction of the blood vessel 20 responds instantaneously to changes in blood flow, but nitric oxide NO is produced and diffuses into the intima, reaches the smooth muscle, and the response delay time until the smooth muscle is relaxed. Is known to occur. That is, a response delay time from the change in shear stress to the change in wall stress occurs. Therefore, in anticipation of the response delay time, a time point that is earlier than the wall stress calculation time by the response delay time is set as a reference time point, and blood vessels are measured based on shear stress at each measurement time point within a predetermined interval before the reference time point. By calculating the shear stress SS1, which is a representative value when diagnosing the function, the blood vessel function can be diagnosed based on the shear stress SS1 and the wall stress WS having a correlation. Further, the shear stress SS1, which is a representative value for diagnosing vascular function, is not an instantaneous value at a certain time point (for example, the reference time point), and is measured within a predetermined interval (20 heartbeat intervals) with the reference time point as an end point. By setting the value to be calculated based on the shear stress SS for each time point, the blood vessel function can be diagnosed based on the shear stress SS1 in consideration of the stimulus applied to the blood vessel wall on a regular basis.

  Further, according to the present embodiment, the shear stress SS is calculated based on the blood flow velocity distribution DS from a two-dimensional or three-dimensional Navier-Stokes equation stored in advance. In this way, an accurate shear stress SS is calculated, and a practical vascular function inspection device 95 can be provided.

  Further, according to the present embodiment, the wall stress WS is calculated based on the minimum blood pressure DBP, the blood vessel diameter d1, and the wall thickness t of the blood vessel 20. In this way, by measuring the minimum blood pressure DBP, the blood vessel diameter d1, and the wall thickness t, an accurate wall stress WS is calculated, and a practical blood vessel function inspection device 95 can be provided.

  Further, according to the present embodiment, the ultrasonic probe 24 that emits (radiates) ultrasonic waves toward the blood vessel 20 has a plurality of ultrasonic oscillators linearly in the longitudinal direction (y-axis direction) of the blood vessel 20. The first short-axis ultrasonic array probe in which the arranged long-axis ultrasonic array probe C and a plurality of ultrasonic oscillators are arranged linearly perpendicular to the longitudinal direction of the blood vessel 20. A and a second short axis ultrasonic array probe B. The blood flow velocity distribution DS is measured by the ultrasonic waves from the long-axis ultrasonic array probe C, and the diameter change rate of the blood vessel 20 is measured by the ultrasonic waves from the first short-axis ultrasonic array probe A. Is measured. Therefore, the measurement of the blood flow velocity distribution DS and the measurement of the diameter change rate of the blood vessel 20 can be performed in parallel using the ultrasonic probe 24 that has been put into practical use.

  In the above-described embodiment, the function index value X1 and the function / material index value X3 are standardized by the above-described shear stress SS, so that the evaluation based on the index value can be made more accurate. FIG. 25 shows changes in data when a predetermined index value is standardized by the shear stress SS. For example, the data indicated by “Δ” on the solid line 1 and the data indicated by “◯” on the broken line 2 have the same value A on the index value, but the above is due to the difference in the shear stress SS. Is. Therefore, by standardizing the index value by the shear stress SS, that is, by changing the index value to the index value in the same shear stress SS state, the data evaluation becomes more accurate. For example, in FIG. 25, when the data indicated by “◯” on the broken line 2 is standardized to the index value at the shear stress SS equal to the data indicated by “Δ” of the solid line 1, the data becomes a value indicated by “□”. . That is, the index value A is changed to the index value B by standardizing with the shear stress SS. In this way, by standardizing the index value with the shear stress SS, more accurate evaluation can be performed based on the standardized index value.

  As described above, according to the present embodiment, since each index value is standardized by the shear stress SS, each index value is further corrected by the shear stress SS, thereby suppressing data variation and improving the blood vessel function. The diagnostic accuracy of the condition is further improved. That is, since the change in the index value due to the difference in the shear stress SS is eliminated, the evaluation based on the index value becomes more accurate.

  As mentioned above, although the Example of this invention was described in detail based on drawing, this is an embodiment to the last, and this invention is applied also in another aspect.

  For example, in the above-described embodiment, when calculating the function index value X1, the property index value X2, and the function / material index value X3, for example, the expansion amount R is the maximum value Rmax as a representative value, and the blood vessel at the time of measuring the maximum value Rmax is used. The above index values are calculated with the diameter d1 and the wall thickness t as representative values, but it is not always necessary to use the maximum value Rmax measurement as a reference. For example, each of the above index values is based on an average value within a predetermined time after the release of ischemia. An index value may be calculated.

In the illustrated embodiment, the wall thickness t, the difference in vessel diameter d1 is the inner diameter of the outer membrane diameter d2 and intimal _{L 1} is the outer diameter of the outer membrane _{L 3} of the blood vessel 20 (= (d2-d1) / 2) is defined as, but in addition to the above, the difference between the medial _{L 2} of the outer diameter (inner diameter of the outer film layer _{L 3)} d3 and vascular diameter d1 indicating the wall thickness t in FIG. 3 (= (d3 Measurement may be performed as defined in -d1) / 2). In other words, the wall thickness t may be a value obtained by adding the thickness of the inner membrane L _{1 and} the thickness of the middle membrane L ₂ .

  In the above-described embodiment, the relationship between the function index value X1 and the property index value X2 is displayed on the monitor image display device 30, but the function / material index value X3 and the age shown in FIGS. And the relationship between the index value X1 and the age can also be displayed. At this time, by displaying the appropriate value corresponding to the age of the subject at the same time, it becomes easy to evaluate the state of the blood vessel function of the subject.

  In the above-described embodiment, the shear stress SS is used as an index value for vascular function diagnosis. For example, when the subject is fixed, the blood viscosity μ does not change. Abnormalities in blood vessel function may be diagnosed based on the speed SR (average value).

  In the above-described embodiment, the shear stress SS is calculated based on the two-dimensional Navier-Stokes equation. However, the shear stress SS is not limited to the above-described calculation method, and a well-known general arithmetic expression. You may calculate using.

  In the above-described embodiment, the wall stress WS is used as an index for diagnosing the blood vessel function. However, instead of the wall stress WS, the wall tension of the blood vessel 20 or the ratio between the wall thickness t and the blood vessel diameter d1 is used. Abnormalities in blood vessel function may be diagnosed based on wall stress-related values that are one-to-one related to wall stress WS. Note that even when diagnosing abnormalities in blood vessel function based on the above parameters, the diagnosis is not substantially different from the diagnosis by the wall stress WS. Therefore, the wall stress WS is a concept including such wall stress related values. Should be interpreted.

  In the above-described embodiment, the time point when the wall stress WS is calculated is based on the end-diastolic end point. It may be at the time of hypertension.

  In the above-described embodiment, in the flowchart of FIG. 24, the shear stress SS is calculated after the wall stress WS is calculated. However, since the shear stress SS is actually calculated at the same time, the order is inconsistent. It is changed as appropriate within the range where there is no.

  In the above-described embodiment, when the end diastole time point is determined, the wall stress calculation unit 98 is immediately executed. However, the wall stress WS such as the blood vessel diameter d1 and the wall thickness t at the end diastole time point is calculated. It is also possible to temporarily store information necessary for calculating the wall stress WS after a predetermined time has elapsed.

  Further, in the above-described embodiment, the end diastole time point is set to the time point when the blood vessel diameter d1 is the minimum value. However, the pulse wave is detected and the lower limit peak time of the pulse wave is set as the end diastole time point. You can also Furthermore, an R wave can be detected in an ECG (electrocardiogram), and that time can be set as the end of diastole.

  It should be noted that what has been described above is merely one embodiment of the present invention, and the present invention can be carried out in various modifications and improvements without departing from the spirit of the present invention.

  10: Sensor holder 12: Hybrid probe unit 14: Living body 16: Upper arm 18: Skin 20: Blood vessel 22, 95: Blood vessel function testing device 23: Pressure sensor 24: Ultrasonic probe 25: Pump 26: Multi-axis drive device 27: Probe surface 28: Electronic control device 29: Pressure control valve 30: Monitor screen display device (display device) 32: Ultrasonic drive control circuit 34: Triaxial drive motor control circuit 36: Magnet stand 38: Unit fixture 42: Tip Portion 44: Connecting member 45: Connecting member 46: Link 47: Link 48: Fitting hole 50: Indirect portion 51: Indirect portion 52: Fixed knob 54: Indirect portion 72: Echo receiving portion 80: Blood vessel Diameter measuring unit 82: Vascular dilation amount measuring unit 84: Vascular wall thickness measuring unit 86: Vascular function index value calculating unit 88, 124: Vascular machine Diagnosis unit 90, 126: Display control unit 92, 128: Storage unit 94: Cuff pressure control unit 95: Blood pressure measurement unit 96: Shear stress calculation unit 98: Wall stress calculation unit 100: Blood flow velocity distribution measurement unit 102: Blood viscosity Distribution calculation unit 104: Shear velocity distribution calculation unit 106: Shear stress distribution calculation unit 122: Wall stress calculation unit 130: Sub-region

Claims (6)

A shear stress calculation unit for calculating shear stress of blood flowing in the blood vessel ;
A wall stress calculator for calculating wall stress acting on the blood vessel wall of the blood vessel ;
Vascular function for diagnosing abnormal vascular function based on whether or not at least one of the calculated shear stress and wall stress is out of an appropriate range of the shear stress and wall stress set in advance A diagnostic unit ,
The shear stress is defined as a reference time point that is a preset time corresponding to a response delay time from the change of the shear stress to the change of the wall stress, and the shear stress is within the predetermined interval before the reference time point. An integrated value of shear stress, an average shear stress value per heartbeat within the predetermined section, an integrated value or an average value of instantaneous values synchronized with the pulse within the predetermined section, or a vascular function test characterized by apparatus. A display device for displaying the calculated relationship between the shear stress and the wall stress in a two-dimensional graph;
In the display device, a region surrounded by the appropriate ranges of the shear stress and the wall stress is displayed in advance,
2. The blood vessel function testing device according to claim 1, wherein a calculated result indicating the relationship between the calculated shear stress and wall stress and a relative position of the region are displayed. A storage unit that sequentially stores the shear stress calculated by the shear stress calculation unit and the wall stress calculated by the wall stress calculation unit;
When displaying the calculation results of the shear stress and wall stress on the display device, the calculation information of the shear stress and wall stress calculated before the previous time stored in the storage unit is displayed in a distinguishable manner. The vascular function testing device according to claim 2, characterized in that:   The vascular function testing device according to claim 1, wherein the shear stress is calculated based on a blood flow velocity distribution from a two-dimensional or three-dimensional Navier-Stokes equation stored in advance.   The vascular function testing device according to claim 1, wherein the wall stress is calculated based on blood pressure, blood vessel diameter, and wall thickness. A shear stress calculation unit for calculating shear stress of blood flowing in the blood vessel ;
A wall stress calculator for calculating wall stress acting on the blood vessel wall of the blood vessel ;
A display device for displaying the calculated relationship between the shear stress and the wall stress in a two-dimensional graph;
In the display device, an area surrounded by an appropriate range set in advance for each of the shear stress and the wall stress is displayed,
A blood vessel function test apparatus, characterized in that a calculation result indicating a relationship between the calculated shear stress and wall stress and a relative position of the region are displayed.

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