JP2015085142A - Organism blood vessel state measuring apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an organism blood vessel state measuring apparatus which suitably detects pulsation timing of a blood vessel.SOLUTION: An organism blood vessel state measuring apparatus includes: a probe direction control part 102 which changes the direction of an ultrasonic probe 24 against a blood vessel 20; a time series waveform detection part 100 which detects a time series waveform of the variation in a radial direction of the blood vessel 20 on the basis of a reflection signal received in correspondence with each direction of the ultrasonic probe 24; and a deflection direction detection part 104 which detects the direction of the ultrasonic probe 24 in which the variation in the radial direction of the blood vessel 20 becomes the largest from the time series waveform corresponding to each direction of the ultrasonic probe 24 detected by the time series waveform detection part 100. Therefore, the organism blood vessel state measuring apparatus can suitably measure the change in the diameter dimension of the blood vessel 20 even when the way of change of the blood vessel 20 is deflected due to a tissue such as a peripheral muscle 70 and constraint with the ultrasonic probe 24 and the like.

Description

  The present invention relates to a biological blood vessel state measuring apparatus that measures the state of a blood vessel based on an ultrasonic reflection signal with respect to a part of blood vessels of a living body, and more particularly to an improvement for suitably detecting the pulsation timing of a blood vessel.

  A living body in which an ultrasonic sensor is brought into contact with a living body, ultrasonic waves are radiated to a blood vessel located under the epidermis, and a state of a blood vessel diameter, a lumen diameter, or the like of the blood vessel is measured based on a reflected signal of the ultrasonic wave A blood vessel state measuring device is known. For example, the blood vessel shape measuring apparatus described in Patent Document 1 is an example. The measurement of the blood vessel state by this biological blood vessel state measuring device is, for example, a time difference process between ultrasonic reflection signals reflected from their boundaries due to a difference in propagation speed between the blood vessel and another tissue, or a combination of the reflection signals. This is performed by distance measurement on an ultrasonic image.

Japanese Patent No. 4444164

  In the blood vessel state measurement, in order to reduce the amount of data, a method of measuring using an ultrasonic image or the like recorded at a constant timing in synchronization with the heart beat is often employed. For example, in the upper arm, the pulse wave arrives at about 50 to 100 (ms) from the R wave in the electrocardiogram, but the propagation of the pulse wave depends on the blood vessel diameter, wall thickness, wall elasticity, etc. There are individual differences (individual differences) in pulse wave propagation time. Therefore, it is required to detect the pulsation timing of the blood vessel from the ultrasonic image or the like. By the way, as an aspect in which the blood vessel diameter of the blood vessel changes, the blood vessel swells and moves, and the like, but it is conceivable that the way of change is deflected due to a tissue such as a surrounding muscle or a restriction by a probe. . That is, depending on the measurement method, a change in the diameter of the blood vessel cannot be measured appropriately, and the pulsation timing of the blood vessel cannot be detected appropriately. The conventional technology cannot solve such a problem. Such a problem has been newly found in the process in which the present inventors have continued intensive studies with the intention of improving the performance of the biological blood vessel state measuring apparatus.

  The present invention has been made in the background of the above circumstances, and an object of the present invention is to provide a biological blood vessel state measuring apparatus that suitably detects the pulsation timing of a blood vessel.

  In order to achieve such an object, the gist of the first invention is that an ultrasonic wave is radiated to a blood vessel located in the epidermis of a living body, and the state of the blood vessel is based on the reflected signal of the ultrasonic wave. A blood vessel state measuring apparatus for measuring a probe, a probe for emitting ultrasonic waves to the blood vessels and receiving reflected signals of the ultrasonic waves, and a probe direction control unit for changing the direction of the probes with respect to the blood vessels Corresponding to each direction of the probe that is changed by the probe direction control unit, and detecting a time series waveform of a change amount in the radial direction of the blood vessel based on the reflected signal received by the probe From the waveform detection unit and the time-series waveform corresponding to each direction of the probe detected by the time-series waveform detection unit, the amount of change in the radial direction of the blood vessel is the largest. A deflection direction detection unit for detecting the direction of the over blanking, is characterized in that it comprises.

  As described above, according to the first aspect of the invention, the probe that radiates ultrasonic waves to the blood vessel and receives the reflected signal of the ultrasonic waves, and the probe direction control unit that changes the direction of the probe with respect to the blood vessel. Corresponding to each direction of the probe that is changed by the probe direction control unit, and detecting a time series waveform of a change amount in the radial direction of the blood vessel based on the reflected signal received by the probe Deflection direction detection for detecting the direction of the probe with the largest amount of change in the radial direction of the blood vessel from the waveform detection unit and the time-series waveform corresponding to each direction of the probe detected by the time-series waveform detection unit Even when the way of changing the blood vessels is deflected due to tissue such as surrounding muscles or restraint by a probe, etc. The change in the diameter of the blood vessel can be suitably determined. That is, it is possible to provide a biological blood vessel state measuring device that suitably detects the pulsation timing of a blood vessel.

  The gist of the second invention subordinate to the first invention is that the time-series waveform detected by the time-series waveform detector corresponding to the direction of the probe detected by the deflection direction detector. A cycle detection unit that detects a cycle, and a pulsation timing detection unit that detects the pulsation timing of the blood vessel based on the cycle of the time-series waveform detected by the cycle detection unit. In this way, the pulsation timing of the blood vessel can be detected in a suitable and practical manner even when the way of blood vessel change is deflected due to tissue such as surrounding muscles or restraint by a probe. be able to.

  The gist of the third invention subordinate to the second invention is that a frame setting unit that sets a frame corresponding to a predetermined time interval in the time-series waveform detected by the time-series waveform detection unit; An intra-frame waveform acquisition unit that shifts the frame set by the frame setting unit in the time direction and acquires the time-series waveform included in the frame at each shift, and the period detection unit includes An autocorrelation function of a time series waveform included in each frame acquired by the intra-frame waveform acquisition unit is calculated, and a period of the time series waveform is detected based on the calculated autocorrelation function. In this way, the pulsation timing of the blood vessel can be detected in a suitable and practical manner.

  The gist of the fourth invention, which is dependent on the third invention, is that the period detection unit calculates the gradient of the autocorrelation function of the time-series waveform included in each frame acquired by the intra-frame waveform acquisition unit. And calculating the period of the time-series waveform based on the calculated gradient of the autocorrelation function. In this way, the pulsation timing of the blood vessel can be detected in a suitable and practical manner.

  The gist of the fifth invention, which is dependent on the fourth invention, is that the period detection unit calculates the gradient of the autocorrelation function of the time-series waveform included in each frame acquired by the intra-frame waveform acquisition unit. The period of the time-series waveform is detected based on the average of the sum of the gradients calculated corresponding to each frame. In this way, the pulsation timing of the blood vessel can be detected in a suitable and practical manner.

It is a perspective view which illustrates the whole structure of the biological blood vessel state measuring apparatus which is one Example of this invention. It is a figure explaining the xyz-axis orthogonal coordinate axis | shaft used in a present Example regarding the positioning of the ultrasonic probe in the biological blood vessel state measuring apparatus of FIG. It is an enlarged view which shows roughly the multilayer film structure of the blood vessel which is a measuring object of the biological blood vessel state measuring apparatus of FIG. It is a figure which illustrates the ultrasonic image of the blood vessel displayed on a monitor screen display apparatus in the measurement of the blood vessel state by the biological blood vessel state measuring apparatus of FIG. 2 is a time chart illustrating the change in the diameter of a blood vessel lumen after release of ischemia in the blood vessel FMD evaluation by the biological blood vessel state measurement apparatus of FIG. 1. It is a functional block diagram explaining the principal part of an example of the control function with which the biological blood vessel state measuring apparatus of FIG. 1 was equipped. It is a figure which shows an example of the appearance of the short-axis image of the blood vessel produced | generated based on a reflected signal by the biological blood vessel state measuring apparatus of FIG. It is a figure explaining the aspect of the change of the vascular diameter of the blood vessel which is a measuring object of the biological vascular state measuring apparatus of FIG. 1 based on the short-axis cross-sectional image. It is a figure explaining the aspect of the change of the vascular diameter of the blood vessel which is a measuring object of the biological vascular state measuring apparatus of FIG. 1 based on the short-axis cross-sectional image. It is a figure explaining the aspect of the change of the vascular diameter of the blood vessel which is a measuring object of the biological vascular state measuring apparatus of FIG. 1 based on the short-axis cross-sectional image. FIG. 10 is a diagram for explaining a difference in appearance of a short-axis image according to the direction of the ultrasonic probe with respect to a blood vessel in which a change in blood vessel diameter is deflected as shown in FIG. 9. FIG. 10 is a diagram for explaining a difference in appearance of a short-axis image according to the direction of the ultrasonic probe with respect to a blood vessel in which a change in blood vessel diameter is deflected as shown in FIG. 9. FIG. 10 is a diagram for explaining a difference in appearance of a short-axis image according to the direction of the ultrasonic probe with respect to a blood vessel in which a change in blood vessel diameter is deflected as shown in FIG. 9. FIG. 12 is a diagram illustrating a time-series waveform detected based on a reflection signal detected by an ultrasonic probe, corresponding to FIG. 11. FIG. 13 is a diagram illustrating a time-series waveform detected based on a reflection signal detected by an ultrasonic probe, corresponding to FIG. 12. It is a figure explaining the example which divides | segments the blood vessel which is a measuring object of the biological vascular state measuring apparatus of FIG. 1 into several blocks equally in the circumferential direction regarding the short-axis cross section. It is a figure explaining a mode that a frame is set to the time-sequential waveform while showing an example of the time-sequential waveform detected by the biological blood vessel state measuring apparatus of FIG. It is a figure which shows the autocorrelation value calculated corresponding to the time series waveform shown in FIG. 2 is a flowchart for explaining a main part of an example of blood vessel wall movement measurement control by the biological blood vessel state measurement device of FIG. 1. It is a flowchart explaining the principal part of an example of the time-sequential waveform creation control by the biological blood vessel state measuring apparatus of FIG. It is a flowchart explaining the principal part of an example of the pulsation peak detection control by the biological blood vessel state measuring apparatus of FIG.

  The blood vessel shape measuring apparatus of the present invention preferably measures the brachial artery, which is an artery in the upper arm epidermis of a living body. Alternatively, the present invention is similarly applied to the measurement of blood vessel parameters such as arteries and veins that can be measured from the epidermis surface such as the forearm portion of the living body and the tibia artery, and blood vessels of other lower limbs, and has an effect.

  The probe provided in the blood vessel shape measuring apparatus of the present invention is preferably composed of two parallel arrays of the first short axis ultrasonic array probe and the second short axis ultrasonic array probe. This is an H-type hybrid type ultrasonic probe having a long-axis ultrasonic array probe connecting the central portions in the longitudinal direction on one plane. Alternatively, the present invention is similarly applied to a blood vessel shape measuring apparatus provided with an inline type or other probe, and there is an effect.

  The blood vessel shape measuring apparatus of the present invention preferably includes an ultrasonic probe having three ultrasonic array probes, but two ultrasonic array probes or four or more ultrasonic arrays. The present invention is also suitably applied to a biological blood vessel state measuring apparatus provided with an ultrasonic probe having a probe.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 shows a probe unit 12 held in a sensor holder 10, and a non-vascularization of a blood vessel 20 such as an artery located directly below the skin 18 from the top of the skin 18 (strictly the epidermis) in the upper arm 16 of the living body 14. It is a perspective view which illustrates the whole structure of the biological blood-vessel state measuring apparatus 22 (henceforth only the measuring apparatus 22) which is one Example of this invention which performs invasive ultrasonic diagnosis.

The probe unit 12 functions as a sensor for detecting biological information related to the blood vessel 20, that is, a blood vessel parameter, and includes a pair of first short-axis ultrasonic array probes 24a parallel to each other, and An H-type having a second short-axis ultrasonic array probe 24b and a long-axis ultrasonic array probe 24c connecting the central portions in the longitudinal direction on a flat probe surface 25 on one plane. The ultrasonic probe 24 is provided. The first short axis ultrasonic array probe 24a, the second short axis ultrasonic array probe 24b, and the long axis ultrasonic array probe 24c are, for example, as shown in FIG. are configured respectively in the longitudinal shape by the piezoelectric ceramic number composed of numbers of ultrasonic transducers (ultrasonic oscillators) a ₁ ~a _n are linearly arranged.

  FIG. 2 is a diagram for explaining xyz-axis orthogonal coordinate axes used in the present embodiment with respect to positioning of the ultrasonic probe 24. In FIG. 2, the longitudinal direction of the first short-axis ultrasonic array probe 24a is the x-axis direction. The longitudinal direction of the long-axis ultrasonic array probe 24c is the y-axis direction. Further, it passes through the intersection of the longitudinal direction of the first short-axis ultrasonic array probe 24a and the longitudinal direction of the long-axis ultrasonic array probe 24c and is orthogonal to the x-axis direction and the y-axis direction. The direction is the z-axis. The probe unit 12 includes a multi-axis drive device (positioning device) 26 that positions the ultrasonic probe 24 in the xyz direction and positions the rotation angle around the axis of each xyz axis. That is, with respect to the xyz-axis orthogonal coordinate axes as shown in FIG. 2, the ultrasonic probe 24 is translated in the x-axis direction by the multi-axis drive device 26, for example. Moreover, it is rotated around the axis of each of the x axis, the y axis, and the z axis.

FIG. 3 is an enlarged view schematically showing the multilayer film configuration of the blood vessel 20 that is the measurement target of the measurement device 22. The blood vessel 20 shown in FIG. 3 is preferably a brachial artery, and has a three-layer structure of an intima L ₁ , a media L ₂ , and an adventitia L ₃ . Since reflection of ultrasonic waves generally occurs at different parts of acoustic impedance, in the measurement of the state of the blood vessel 20 using ultrasonic waves, the boundary surface between the blood in the blood vessel lumen and the intima L ₁ and the medium are actually used. The boundary surface between the membrane L ₂ and the outer membrane L ₃ is displayed in white, and the tissue is displayed in black and white.

  As shown in FIG. 1, the measuring device 22 includes an electronic control device 28 composed of a so-called microcomputer having a CPU that processes an input signal in accordance with a program stored in the ROM in advance using the temporary storage function of the RAM. A monitor screen display device (image display device) 30, an ultrasonic drive control circuit 32, and a triaxial drive motor control circuit 34. In the measurement of the blood vessel state by the measurement device 22, when a drive signal is supplied from the ultrasonic drive control circuit 32 by the electronic control device 28, the first short axis of the ultrasonic probe 24 in the probe unit 12. Ultrasonic array probe 24a, second short axis ultrasonic array probe 24b, and long axis ultrasonic array probe 24c generate beam-like ultrasonic waves by well-known beam forming drive. Sequentially emitted. Then, an ultrasonic reflected signal is detected by the first short axis ultrasonic array probe 24a, the second short axis ultrasonic array probe 24b, and the long axis ultrasonic array probe 24c. Then, processing of the detected ultrasonic reflection signal is performed in the electronic control device 28, so that an ultrasonic image under the skin 18 is generated and displayed on the monitor screen display device 30.

  As shown in FIG. 1, the measurement apparatus 22 includes an ultrasonic drive control unit 80, a detection processing unit 82, an ultrasonic signal processing unit 84, a triaxial drive motor control unit 86, a cuff pressure control unit 88, and a blood vessel state evaluation unit. 90, and a display control unit 92. These control functions are preferably functionally provided in the electronic control device 28, but a part or all of these control functions are separate from the electronic control device 28. And may perform control described in detail below by mutually communicating information.

  FIG. 4 shows the positional relationship between the ultrasound probe 24 and the blood vessel 20 positioned at a predetermined measurement position when an ultrasound image of the blood vessel 20 is generated in the measurement of the blood vessel state by the measurement device 22. It is a figure which shows and illustrates the ultrasonic image of the blood vessel displayed on the said monitor screen display apparatus 30 in such a positional relationship. For example, as shown in FIG. 4A, the monitor screen display device 30 is configured to display an ultrasonic image (first image) corresponding to an ultrasonic reflection signal detected by the first short-axis ultrasonic array probe 24a. An ultrasonic image (second short-axis image) corresponding to an ultrasonic reflection signal detected by the first short-axis image display region G1 displaying the short-axis image) and the second short-axis ultrasonic array probe 24b. ) And an ultrasonic image (long axis image, blood vessel longitudinal section image) corresponding to the ultrasonic reflection signal detected by the long axis ultrasonic array probe 24c. A long-axis image display area G3 to be displayed. Preferably, the first short-axis image display area G1, the second short-axis image display area G2, and the long-axis image display area G3 have a common vertical axis indicating a depth dimension from the skin 18. Is. In addition, “ImA, ImB” in FIG. 4A indicates a transverse section of the blood vessel 20, respectively.

  The measuring device 22 preferably has a diameter, inner film thickness, plaque, blood flow velocity, etc. of the blood vessel 20 based on an ultrasonic reflection signal output from the ultrasonic probe 24 to the blood vessel 20. FMD (Flow-Mediated Dilation) that measures blood flow is evaluated. When evaluating the FMD, the monitor screen display device 30 displays, for example, the rate of change of the intima diameter in the blood vessel 20, that is, the lumen diameter expansion rate R in time series. When the FMD is evaluated and an ultrasonic image of the blood vessel 20 is generated, the ultrasonic probe 24 is placed in the electronic control unit 28 so that the ultrasonic probe 24 is at a predetermined measurement position P with respect to the blood vessel 20 to be measured. Positioning is performed by driving the multi-axis driving device 26 supplied with a driving signal from the three-axis driving motor control circuit 34 by the provided three-axis driving motor control unit 86. The predetermined measurement position P is preferably such that the first short axis ultrasonic array probe 24a and the second short axis ultrasonic array probe 24b are orthogonal to the blood vessel 20, The long axis ultrasonic array probe 24 c is parallel to the blood vessel 20. Referring to FIG. 4, the predetermined measurement position P is a position where “a = b, c = d, e = f” in FIG. That is, the distance from the first short-axis ultrasonic array probe 24a to the center of the blood vessel 20 and the distance from the second short-axis ultrasonic array probe 24b to the center of the blood vessel 20 are mutually different. It is the measurement position where the image of the blood vessel 20 is located at the center in the width direction in both the first short-axis image display region G1 and the second short-axis image display region G2.

  In the measurement of the blood vessel state by the measurement device 22, the sensor holder 10 is in a state in which the blood vessel 20 positioned immediately below the skin 18 of the upper arm 16 in the living body 14 is lightly contacted so as not to deform. The probe unit 12 is held in a desired posture. Preferably, the probe unit 12 is held in a desired posture so that the position of the ultrasonic probe 24 in the three-dimensional space is the predetermined measurement position P with respect to the blood vessel 20. Preferably, between the end face of the ultrasonic probe 24 and the skin 18 in the probe unit 12, the attenuation of the ultrasonic wave, the reflection and scattering at the boundary surface are suppressed, and the ultrasonic image is made clear. Well-known coupling agents such as jelly, olive oil and glycerin, water bags in which water is confined in a resin bag, and the like are interposed.

  As shown in FIG. 1, the sensor holder 10 includes, for example, a magnet base 36 that is fixed to a desk, a pedestal, or the like by magnetic attraction, a unit fixture 38 to which the probe unit 12 is fixed, and the magnet. Connecting members 44 and 45 each having one end fixed to the base 36 and the unit fixture 38 and having a tip 42 formed in a spherical shape, and the magnet base 36 and the unit fixture 38 via the connecting members 44 and 45. And a universal arm 40 that is connected and supported so as to be relatively movable. The universal arm 40 includes two links 46 and 47 that are pivotably connected to each other, and a fitting that is rotatably fitted to the distal end portion 42 at one end of the links 46 and 47. The curved joint portions 50 and 51 each having a hole 48 and the other ends of the links 46 and 47 are connected to the other ends of the links 46 and 47 so as to be capable of relative rotation with each other and screwed into screw holes extending through the connecting portions. And a rotary joint portion 54 that is made relatively non-rotatable by a fastening force obtained by tightening the fixed knob 52 with the male thread.

  The multi-axis drive device 26 is, for example, an x-axis rotation (yaw) fixed to the unit fixture 38 in order to position the rotation position of the ultrasonic probe 24 around the x-axis by an x-axis rotation actuator. A mechanism, an x-axis translation mechanism for positioning the translation position of the ultrasonic probe 24 in the x-axis direction by an x-axis translation actuator, and a rotational position of the ultrasonic probe 24 about the y-axis by a y-axis actuator And a z-axis rotation mechanism for positioning the rotation position around the z-axis of the ultrasonic probe 24 by a z-axis actuator. With such a configuration, the multi-axis drive device 26 controls the positioning state of the ultrasonic probe 24 in accordance with a command from the electronic control device 28.

The ultrasonic drive control circuit 32 controls the emission of ultrasonic waves from the ultrasonic probe 24 to the blood vessel 20 according to a command from an ultrasonic drive control unit 80 provided in the electronic control device 28. For example, the plurality of which are arranged in a row in the first ultrasonic detector array 24a for the minor axis of the ultrasonic transducer a ₁ to a _n, a certain number from the ultrasonic transducer a ₁ of the end A group of ultrasonic transducers, for example, a beam forming drive that simultaneously drives at a frequency of about 10 MHz while giving a predetermined phase difference to each of ₁₅ a _{1 to} a ₁₅ , thereby achieving super-convergence in the arrangement direction of the ultrasonic transducers. A sound beam is sequentially emitted toward the blood vessel 20. Then, a reflected wave for each radiation when the ultrasonic beam is scanned while scanning the ultrasonic transducers one by one is received and input to the electronic control unit 28. The reflected wave signal input to the electronic control unit 28 is detected by the detection processing unit 82 and processed as information capable of image synthesis by the ultrasonic signal processing unit 84. The ultrasonic signal processing unit 84 performs, for example, time difference processing between ultrasonic reflection signals reflected from their boundaries due to a difference in propagation velocity between the blood vessel 20 and other tissues, and an ultrasonic image based on the reflection signals. Perform synthesis processing.

The electronic control unit 28 synthesizes an image based on the reflected wave of the ultrasonic wave received by the ultrasonic probe 24, and forms a short-axis image, that is, a cross-sectional image, and a long-axis image of the blood vessel 20 under the skin 18. An image, that is, a longitudinal section image is generated and displayed on the monitor screen display device (image display device) 30. In addition, from the short-axis image and the long-axis image of the blood vessel 20 generated as described above, the diameter of the blood vessel 20 or the endothelium diameter (lumen diameter) d ₁ that is the diameter of the endothelium 70 is calculated. Further, in order to evaluate the endothelial function of the blood vessel 20, the expansion rate (change rate) R (%) of the blood vessel lumen diameter representing FMD (blood flow-dependent vasodilatation reaction) after ischemic reactive hyperemia. 100 × (d ₁ −d _a ) / d _a ] is calculated. “D _a ” in this equation indicates the diameter of the blood vessel lumen (base diameter, rest diameter) at rest.

  In the measurement of the blood vessel state by the measurement device 22, the measurement site in the living body 14, for example, the upper arm 16 is pressed by a pressurizing device such as a cuff 62 to block the blood flow, and a part of the living body 14 (peripheral rather than the ischemic part) The blood flow is rapidly released and the blood flow of the blood vessel 20 at the measurement site is rapidly increased, so that the blood flow from the endothelium accompanying the increase in shear stress to the blood vessel wall is increased. The production of nitric oxide (NO) occurs, and the endothelial function is determined by examining the relaxed state of smooth muscle depending on the nitric oxide.

FIG. 5 is a time chart illustrating the change in the vascular lumen diameter d ₁ after release of ischemia (blood transfer) in the FMD evaluation of the blood vessel 20 by the measuring device 22. In FIG. 5, the time point t1 represents the time when the ischemia is released, the blood vessel lumen diameter d ₁ starts to expand from the time point t2, and the blood vessel lumen diameter d ₁ reaches its maximum value d _MAX at the time point t3. It has been shown. Therefore, the expansion rate R of the blood vessel lumen diameter calculated by the electronic control device 28 becomes maximum at time t3.

The ischemia for FMD evaluation of the blood vessel 20 by the measuring device 22 is performed by an air pump 58, a pressure control valve 60, and the like by a cuff pressure control unit 88 provided in the electronic control device 28 as shown in FIG. It is executed by being controlled. For example, according to a command from the electronic control unit 28, the original pressure from the air pump 58 is controlled by the pressure control valve 60 and supplied to the cuff 62 wound around the upper arm 16. Specifically, the ischemia for FMD evaluation is performed by increasing the pressure (cuff pressure) of the cuff 62 to a predetermined ischemic cuff pressure that exceeds the maximum blood pressure of the living body 14. At this time, the cuff pressure control unit 88 detects the cuff pressure according to a signal from the pressure sensor 64 that detects the pressure (cuff pressure) of the cuff 62. In FIG. 5, for example, the cuff pressure control unit 88 maintains the cuff pressure at the ischemic cuff pressure for a predetermined time before the release of the ischemia, that is, a predetermined time before the time t1, and when the ischemia is released (time t1). The cuff pressure is immediately reduced to atmospheric pressure. As a result, the blood vessel 20 at the measurement site P is rapidly congested, and the measurement device 22 measures the blood vessel diameter d _max after the confusion of the target blood vessel 20 from the ischemic state.

  FIG. 6 is a functional block diagram for explaining a main part of an example of a control function provided in the blood vessel state evaluation unit 90. The blood vessel state evaluation unit 90 is configured to output ultrasonic waves emitted from the ultrasonic probe 24 to the blood vessel 20 located in the epidermis of the living body 14 by the ultrasonic drive control circuit 32 (ultrasonic drive control unit 80). On the other hand, the state of the blood vessel 20 is determined based on the reflected signal of the ultrasonic wave received by the ultrasonic probe 24 and subjected to detection by the detection processing unit 82 and signal processing by the ultrasonic signal processing unit 84. To evaluate. In order to perform such control, the blood vessel state evaluation unit 90 includes a time-series waveform detection unit 100, a probe direction control unit 102, a deflection direction detection unit 104, a frame setting unit 106, an in-frame waveform acquisition unit 108, and a period detection unit. 110 and a pulsation timing detection unit 112. Hereinafter, the processing of each control unit will be described in detail.

  The time-series waveform detector 100 detects a time-series waveform of the radial change amount of the blood vessel 20 based on the reflected signal (RF signal) received by the ultrasonic probe 24. For example, ultrasonic waves emitted from the first short axis ultrasonic array probe 24a to the blood vessel 20 are received by the first short axis ultrasonic array probe 24a, and the ultrasonic waves are received. Based on the reflection signal signal-processed by the processing unit 84, a change amount of the radial dimension related to the short-axis cross-sectional shape of the blood vessel 20 is calculated, and a time-series change (change with time) of the change amount is detected. Specifically, a reflection signal passing through the vicinity of the center of the blood vessel 20 is detected from among a series of reflection signals received by the first short-axis ultrasonic array probe 24a. The amount of change in the radial direction of the blood vessel 20 is calculated by a method as described in the above, and the calculated amount of change is stored in a predetermined storage device provided in the electronic control device 28 or the like in time series.

  The blood vessel state evaluation unit 90 preferably generates a cross-sectional image of the blood vessel 20 based on the reflection signal received by the ultrasonic probe 24 by a known technique. For example, with respect to the short-axis cross-sectional shape based on the reflected signal detected by the detection processing unit 82, a differential value of luminance in the direction of 360 ° from the center position of the blood vessel 20 is calculated, and a position with a large change (the differential value is specified). A position, edge, etc. that is greater than or equal to the value is determined (extracted) as a feature point. Preferably, the reflected signal detected by the detection processing unit 82 is squared by the ultrasonic signal processing unit 84 and converted into a signal corresponding to the signal power, and the signal power is subjected to envelope processing. By smoothing, it is converted into a smoothed signal that changes smoothly. Then, a grayscale signal is generated by converting the magnitude of the smoothed signal into a stepwise grayscale, and a two-dimensional ultrasonic cross-sectional image indicated by the grayscale is generated. For example, a short-axis image of the blood vessel 20, i.e., a cross-section, based on the reflected wave of the ultrasonic waves received by the first short-axis ultrasonic array probe 24 a and the second short-axis ultrasonic array probe 24 b. A plane image is generated.

  FIG. 7 is a diagram illustrating an example of how a short-axis image of the blood vessel 20 generated by the blood vessel state evaluation unit 90 based on the reflected signal is seen. In FIG. 7, the emission direction of the ultrasonic waves from the ultrasonic probe 24 (the first short axis ultrasonic array probe 24a) is indicated by a broken-line arrow, and a boundary 66 between the lumen and the wall in the blood vessel 20 is indicated by one point. Each is indicated by a chain line. The cross-sectional image of the blood vessel 20 generated based on the reflected signal received by the ultrasonic probe 24 is not necessarily drawn corresponding to the entire circumference of the blood vessel 20, and is in the direction of ultrasonic radiation. Accordingly, a characteristic point in the blood vessel 20, for example, a part of the boundary 66 between the lumen and the wall is depicted so as to be visible. For example, as shown in FIG. 7, the endothelium 68 (inner peripheral surface of the blood vessel wall) of the blood vessel 20 is depicted as a pair of arcuate curves in the blood vessel 20 in the ultrasonic cross-sectional image. That is, the short-axis image of the blood vessel 20 generated based on the reflected signal is, for example, within a predetermined angle range with respect to the normal to the radiation direction of the ultrasonic wave in the blood vessel wall of the blood vessel 20. Only the wall is drawn. The diameter of the blood vessel 20 is obtained from the distance between a pair of arcuate curves corresponding to the endothelium 68. The time-dependent change in the interval between the pair of arcuate curves (difference in feature points between time-changing frames) corresponds to the time-dependent change in the diameter of the blood vessel 20. Therefore, the change over time of the blood vessel 20 is detected based on the change over time of the interval between the pair of arcuate curves, and the blood vessel state of the blood vessel 20 is evaluated. Further, a method of directly measuring the movement amount of the blood vessel wall of the blood vessel 20 by using a phase correlation related to the reflected signal, a Doppler method, an optical flow method using image information, or the like is also employed.

  8-10 is a figure explaining the change mode of the blood vessel diameter of the said blood vessel 20 based on the short-axis cross-sectional image, and has shown the mode that the blood vessel diameter was expanded (expanded) with the broken line. The pulsation of the blood vessel 20 ideally expands (expands) or contracts (shrinks) with a uniform amount of change in the radial direction as shown in FIG. 8 without being deflected in the radial direction of the blood vessel 20. However, in reality, it is conceivable that the radial change of the blood vessel 20 is deflected due to the restraint (compression) by the ultrasonic probe 24 or a tissue such as a surrounding muscle. For example, depending on the restraint by the ultrasonic probe 24 and the like, as shown in FIG. 9, the enlargement or reduction is biased in a predetermined direction (in the example shown in FIG. 9, the upper left direction with respect to the paper surface). That is, in the example shown in FIG. 9, the change amount of the blood vessel diameter in the upper left direction toward the paper surface is relatively large, and the change amount of the blood vessel diameter in the vertical direction and the left and right direction is smaller than that. The blood vessel diameter hardly changes in the upper right direction and the lower left direction. As shown in FIG. 10, when a muscle 70 exists around the blood vessel 20, the blood vessel diameter of the blood vessel 20 hardly changes in the direction in which the muscle 70 exists, and is deflected in a direction to avoid the muscle 70. Thus, the blood vessel diameter of the blood vessel 20 changes. That is, in the example shown in FIG. 10, the blood vessel diameter of the blood vessel 20 is difficult to change in the vertical direction with respect to the paper surface on which the muscle 70 exists, and the blood vessel 20 is deflected leftward toward the paper surface to avoid the muscle 70. The blood vessel diameter changes.

  FIGS. 11 to 13 are diagrams for explaining the difference in the appearance of the short-axis image according to the direction of the ultrasonic probe 24 with respect to the blood vessel 20 in which the change in blood vessel diameter is deflected as shown in FIG. In FIGS. 11 to 13, generation of the first short axis image by the first short axis ultrasonic array probe 24 a is described. However, the second short axis ultrasonic array probe 24 b is described. The same applies to the generation of the second short-axis image by. The radiation direction of the ultrasonic waves radiated from the ultrasonic probe 24 to the blood vessel 20 varies depending on the direction (angle) of the ultrasonic probe 24 with respect to the blood vessel 20.

  As shown in FIG. 9, in the example in which the change in blood vessel diameter in the blood vessel 20 is deflected in the upper left direction, as shown in FIG. 11, ultrasonic waves are emitted from the upper left to the lower right with respect to the blood vessel 20. Then, by generating a short axis image based on the reflected signal, the amount of change in the blood vessel diameter in the blood vessel 20 can be detected most suitably. FIG. 14 shows the time-series waveform detection unit 100 based on the reflected signal detected by the ultrasonic probe 24 when the direction of the ultrasonic probe 24 relative to the blood vessel 20 is in the state shown in FIG. It is a figure which illustrates the time series waveform detected. In FIG. 14, the threshold for detecting the peak of the change amount of the blood vessel diameter of the blood vessel 20 is indicated by a one-dot chain line. In the example shown in FIG. 14, since the time series waveform periodically exceeds the threshold, it is easy to detect the peak of the time series waveform.

  In the example in which the change in the blood vessel diameter in the blood vessel 20 is deflected in the upper left direction as shown in FIG. 9, as shown in FIG. 12, ultrasonic waves are emitted from the top to the bottom with respect to the blood vessel 20, In the aspect in which the short axis image is generated based on the reflected signal, the change amount of the blood vessel diameter in the blood vessel 20 detected is smaller than that in the example shown in FIG. FIG. 15 shows the time-series waveform detector 100 based on the reflected signal detected by the ultrasonic probe 24 when the direction of the ultrasonic probe 24 relative to the blood vessel 20 is in the state shown in FIG. It is a figure which illustrates the time series waveform detected, and has shown the time series waveform shown in FIG. 14 with the broken line for the comparison. As shown in FIG. 15, in the relative positional relationship between the blood vessel 20 and the ultrasonic probe 24 shown in FIG. 12, the time series waveform detected by the time series waveform detector 100 is changed to the time series waveform shown in FIG. Compared to a small change amount as a whole, Therefore, the threshold value indicated by the alternate long and short dash line cannot suitably detect the peak of the change amount of the blood vessel diameter of the blood vessel 20, and the threshold value needs to be changed (lowered). As shown in FIG. 13, in a mode in which ultrasonic waves are radiated from the upper right to the lower left with respect to the blood vessel 20 and a short axis image is generated based on the reflected signal, it is detected by the time-series waveform detecting unit 100. The time series waveform corresponds to a smaller change amount.

  As described with reference to FIGS. 11 to 15, on the premise that the way of changing the blood vessel diameter of the blood vessel 20 is deflected due to the tissue such as the surrounding muscle 70 or the restraint by the ultrasonic probe 24, etc. Depending on the direction (angle) of the ultrasonic probe 24 with respect to the blood vessel 20, the change in the diameter of the blood vessel 20 cannot be measured suitably. Furthermore, in the ultrasonic image, there is a direction in which the blood vessel wall of the blood vessel 20 cannot be depicted as an image depending on the reflection direction of the ultrasonic wave or the overlapping state of the blood vessel 20. Therefore, in this embodiment, as will be described in detail below, measurement is performed while changing the direction of the ultrasonic probe 24 with respect to the blood vessel 20, and a time-series waveform in which the amount of change in the radial direction of the blood vessel 20 is the largest. Is used to evaluate the blood vessel 20.

  The probe direction control unit 102 shown in FIG. 6 changes the direction of the ultrasonic probe 24 relative to the blood vessel 20. The direction of the ultrasonic probe 24 with respect to the blood vessel 20 is, for example, that the z-axis shown in FIG. 2 passes through the center of the blood vessel 20 (long axis) and the long axis direction of the blood vessel 20 and FIG. The relative positional relationship between the ultrasound probe 24 and the blood vessel 20 in which the y-axis direction shown is parallel corresponds to the x-axis direction shown in FIG. That is, the change in the x-axis direction in the ultrasonic probe 24 corresponds to the change in the direction of the ultrasonic probe 24 with respect to the blood vessel 20. Specifically, the probe direction control unit 102 controls the three-axis drive motor control circuit 34 via the three-axis drive motor control unit 86, and the multi-axis drive device 26 controls the ultrasonic probe 24 to x. By translating in the axial direction and rotating around the y-axis, the ultrasound probe 24 and the blood vessel in which the z-axis passes through the center of the blood vessel 20 and the major axis direction of the blood vessel 20 is parallel to the y-axis direction. While maintaining the relative positional relationship with 20, the x-axis direction of the ultrasonic probe 24 is changed. In other words, the radiation direction of the ultrasonic wave radiated from the ultrasonic probe 24 to the blood vessel 20 is changed.

  The time-series waveform detection unit 100 corresponds to each direction of the ultrasonic probe 24 changed by the probe direction control unit 102, and based on the reflected signal received by the ultrasonic probe 24, the blood vessel 20 A time-series waveform of the amount of change in the radial direction is detected. That is, the blood vessel is determined based on the reflected signal received by the ultrasonic probe 24 corresponding to each direction of the ultrasonic probe 24 with respect to the blood vessel 20, which is determined according to control by the probe direction control unit 102. A time-series waveform of 20 radial variations is detected and stored in a predetermined storage device. Preferably, the probe direction controller 102 changes the x-axis direction of the ultrasonic probe 24 by a predetermined angle (for example, 45 ° as shown in comparison with FIGS. The direction of the ultrasonic probe 24 is determined, and a time-series waveform of the amount of change in the radial direction of the blood vessel 20 is detected based on the reflected signal received by the ultrasonic probe 24 for each direction. Preferably, as shown in FIG. 16, the blood vessel 20 is equally divided into a plurality of blocks (four blocks 1 to 4 in the example shown in FIG. 16) in the circumferential direction with respect to the short-axis cross section thereof, and the probe While changing the block in which the ultrasonic probe 24 is included by the direction control unit 102, the amount of change in the radial direction of the blood vessel 20 is changed based on the reflected signal received by the ultrasonic probe 24 corresponding to each block. Detect time series waveforms. That is, a relative position where the ultrasonic probe 24 is located in each block defined in the blood vessel 20 (for example, a position where the y-axis in the ultrasonic probe 24, that is, the long-axis ultrasonic array probe 24c is included in each block) ), A time-series waveform of the amount of change in the radial direction of the blood vessel 20 is detected based on the reflected signal received by the ultrasonic probe 24.

  The deflection direction detection unit 104 has the largest amount of change in the radial direction of the blood vessel 20 from the time series waveform corresponding to each direction of the ultrasonic probe 24 detected by the time series waveform detection unit 100. The direction of the ultrasonic probe 24 is detected. That is, corresponding to each direction of the ultrasonic probe 24 with respect to the blood vessel 20 changed by the probe direction control unit 102 (for each direction), the blood vessel 20 detected by the time-series waveform detection unit 100. The time-series waveforms of the radial variation are compared, and the time-series waveform having the largest radial variation of the blood vessel 20 is determined. Then, the direction of the ultrasonic probe 24 corresponding to the determined time-series waveform is detected as the direction of the ultrasonic probe 24 in which the amount of change in the radial direction of the blood vessel 20 is the largest.

  The period detector 110 detects the period of the time series waveform detected by the time series waveform detector 100. That is, the pulse period of the blood vessel 20 synchronized with the heart beat of the living body 14 is detected. Preferably, a plurality of peaks (maximum values) in the time series waveform detected by the time series waveform detection unit 100 are detected, and the period of the time series waveform is detected from the periodicity of the plurality of peaks. Preferably, the period of the time series waveform detected by the time series waveform detection unit 100 corresponding to the direction of the ultrasonic probe 24 detected by the deflection direction detection unit 104 is detected. That is, the time detected by the time-series waveform detecting unit 100 corresponding to the direction of the ultrasonic probe 24 detected by the deflection direction detecting unit 104 and having the largest amount of change in the radial direction of the blood vessel 20. A plurality of peaks in the series waveform are detected, and the period of the time series waveform is detected from the periodicity of the plurality of peaks. Preferably, with respect to the time series waveform detected by the time series waveform detection unit 100 corresponding to the direction of the ultrasonic probe 24 detected by the deflection direction detection unit 104, the period detection unit 110 shown below. The period is detected by the process.

  The frame setting unit 106 sets a frame corresponding to a predetermined time interval in the time series waveform detected by the time series waveform detection unit 100. FIG. 17 is a diagram illustrating an example of a time-series waveform detected by the time-series waveform detection unit 100 and a manner in which a frame is set in the time-series waveform. As shown in FIG. 17, the frame setting unit 106 preferably sets a frame corresponding to a predetermined time interval in the time-series waveform detected by the time-series waveform detection unit 100, and sets the frame as a time. Shift in the direction (translate). That is, the frame 1 is set by shifting a predetermined width in the time direction from the frame 1 set first, the frame 3 is set by shifting the predetermined width in the time direction, and so on. The frames corresponding to the time intervals are sequentially set while shifting by a predetermined width in the time direction. The time interval corresponding to the frame is preferably a size including two to three periods of the time-series waveform, and is about 65 (ms) in the example shown in FIG. The frame shift width (translation width in the time direction) is preferably about 10 (ms). Preferably, the frame setting unit 106 may apply the frame while changing a time interval corresponding to the frame.

  The intra-frame waveform acquisition unit 108 acquires the time series waveform included in the frame set by the frame setting unit 106. That is, a time series waveform included in a time interval corresponding to the frame set by the frame setting unit 106 is acquired (extracted) from among the time series waveforms detected by the time series waveform detection unit 100. The intra-frame waveform acquisition unit 108 acquires the time-series waveform included in the frame at each shift in response to the control of shifting the frame in the time direction by the frame setting unit 106, and a predetermined storage device Remember me.

  The period detection unit 110 preferably calculates an autocorrelation function (autocorrelation value) of a time series waveform included in each frame acquired by the intra-frame waveform acquisition unit 108, and calculates the calculated autocorrelation function To detect the period of the time series waveform. FIG. 18 is a diagram showing autocorrelation values calculated corresponding to the time-series waveforms shown in FIG. The true value of the period in the time series waveform shown in FIG. 17 is 22 (ms). As shown in FIG. 18, the period detection unit 110 preferably has a phase where the autocorrelation value of the time-series waveform included in each frame acquired by the intra-frame waveform acquisition unit 108 is maximum (maximum). The value is calculated as the period of the time series waveform. In the example shown in FIG. 18, there is a local maximum value of the autocorrelation value at a position of about 22 to 23 (ms), and it can be seen that it is in good agreement with the true value of the period in the time series waveform shown in FIG. .

  The period detection unit 110 preferably calculates the gradient of the autocorrelation function of the time-series waveform included in each frame acquired by the intra-frame waveform acquisition unit 108, and uses the calculated autocorrelation function gradient. Based on this, the period of the time series waveform is detected. The gradient of the autocorrelation function of the time series waveform corresponds to the time differential value of the autocorrelation function. By calculating the gradient of the autocorrelation function of the time series waveform, the influence of noise in the time series waveform can be reduced and the peak can be emphasized, and such a peak can be suitably detected. More preferably, the gradient of the autocorrelation function of the time series waveform included in each frame acquired by the intra-frame waveform acquisition unit 108 is calculated, and the sum of the gradients calculated corresponding to each frame is calculated. The period of the time series waveform is detected based on the average. The period detection unit 110 preferably performs the detection using a value corresponding to the maximum value (maximum value) of the gradient of the autocorrelation function of the time series waveform as a peak of the time series waveform. According to such a process, the pulsation cycle of the blood vessel 20 can be detected in a more suitable and practical manner. Preferably, when the blood vessel 20 is measured by the measuring device 10, the processing by the cycle detection unit 110 described in detail above is repeatedly executed (continued), and when the movement of the blood vessel 20 has changed, The period of change in the diameter of the blood vessel 20 is updated. With such a process, it is possible to suppress the removal of timing related to the pulsation cycle of the blood vessel 20.

  The pulsation timing detector 112 shown in FIG. 6 detects the pulsation timing of the blood vessel 20 based on the period of the time-series waveform detected by the period detector 110. The pulsation timing of the blood vessel 20 is a timing at which the blood vessel 20 pulsates in synchronization with the heart pulsation (heartbeat) in the living body 14, and preferably the blood vessel diameter is maximum (maximum) or minimum ( This corresponds to the timing of (minimum). Preferably, the pulsation timing detection unit 112 preferably includes, among the frames acquired by the intra-frame waveform acquisition unit 108 based on the period of the time series waveform detected by the cycle detection unit 110, the frame. A frame (beat frame) corresponding to the pulse timing of the blood vessel 20 is detected. For example, a frame including the peak of the time series waveform is set as a template in advance, and a frame having the maximum autocorrelation function with the template as a reference is detected as a frame corresponding to the pulsation timing of the blood vessel 20. As described above, the pulsation timing of the blood vessel 20 is suitably detected based on the period of the time-series waveform detected by the period detection unit 110. That is, the robustness of heartbeat detection can be improved based on the periodicity of the movement of the blood vessel 20. Preferably, a threshold value related to the time series waveform is set based on the waveform of the pulsation timing detected by the pulsation timing detection unit 112, and is used for detection of the subsequent pulsation timing.

  FIG. 19 is a flowchart for explaining a main part of an example of blood vessel wall movement measurement control by the electronic control device 28 of the measuring device 22, and is repeatedly executed at a predetermined cycle.

  First, in step (hereinafter, step is omitted) SA1, an ROI (region of interest) is set around the short-axis cross section of the blood vessel 20 to be observed. Next, in SA2, image differentiation processing is performed on the reflected signal received by the ultrasonic probe 24, and a portion (such as an edge) where the change in luminance is large is extracted as a feature point. Next, in SA3, the image pattern around the feature point extracted in SA2 is stored in a predetermined storage device provided in the electronic control unit 28 or the like. Next, in SA4, a portion where the image pattern stored in SA3 matches is detected in a new image (image acquired after a predetermined time has elapsed from the previously acquired image). Next, in SA5, the movement amount between the two images (image patterns) detected in SA4 is calculated and stored in a predetermined storage device. Next, at SA6, as shown in FIG. 16, with respect to the feature points belonging to each block (region block) set in the circumferential direction of the short-axis cross-sectional image of the blood vessel 20, the movement amount stored at SA5 is the average. Calculated. Next, in SA7, it is determined whether or not the calculation of the movement amount corresponding to all the blocks set in the circumferential direction of the blood vessel 20 has been completed. If the determination at SA7 is affirmative, the routine is terminated accordingly. If the determination at SA7 is negative, the direction of the ultrasound probe 24 with respect to the blood vessel 20 is determined as follows at SA8. After the direction (angle) corresponding to the block is changed, the process after SA1 is executed again.

  FIG. 20 is a flowchart for explaining a main part of an example of time-series waveform generation control by the electronic control device 28 of the measuring device 22, and is repeatedly executed at a predetermined cycle. The control shown in FIG. 20 is preferably executed in parallel with the control shown in FIG.

  First, in SB1, the movement amount for each block set in the circumferential direction of the blood vessel 20, that is, time series data (time series waveform) of the movement amount calculated in SA6 in the control shown in FIG. It is stored in a predetermined storage device. Next, in SB2, among the time series data stored in SB1, time series data corresponding to an arbitrary time zone width is stored as a template in a predetermined storage device.

  FIG. 21 is a flowchart for explaining a main part of an example of pulsation peak detection control by the electronic control device 28 of the measuring device 22, and is repeatedly executed at a predetermined cycle. The control shown in FIG. 21 is preferably executed in parallel with the control shown in FIGS. 19 and 20 described above.

  First, in SC1, the template of the movement amount stored in the storage device, that is, the time series data corresponding to the same time interval as the template width set in SB2 in the control shown in FIG. Correlation is determined from the template. That is, the autocorrelation value of the time-series data included in each frame is calculated while the frame corresponding to the time interval is shifted. Next, in SC2, among the blocks set in the circumferential direction of the blood vessel 20, the block having the largest autocorrelation calculated in SC1 is determined as the cycle detection block. And the pitch period of time series data is detected regarding the period detection block. Next, in SC3, after the period of the time-series data is detected, in the time-series data of the movement amount that is continuously input, the beat is around the next pulsation time predicted based on the detected period. A dynamic peak is detected. Next, in SC4, it is determined whether or not the time-series data of the movement amount that is continuously input has the template width set in SB2. When the determination at SC4 is negative, the processing after SC3 is executed again. When the determination at SC4 is affirmative, detection of the pulsation peak of the blood vessel 20 is terminated at SC5. It is determined whether or not. If the determination of SC5 is affirmed, this routine is terminated accordingly, but if the determination of SC5 is negative, the time-series data corresponding to an arbitrary time zone width is a new template in SC6. After that, the processes after SC3 are executed again.

  In the above control, SA1 to SA6 are the operation of the time-series waveform detection unit 100, SA7 and SA8 are the operation of the probe direction control unit 102, SC2 is the operation of the deflection direction detection unit 104, and SB1 and SB2 are SC1 corresponds to the operation of the frame setting unit 106, SC1 corresponds to the operation of the intra-frame waveform acquisition unit 108, SC2 corresponds to the operation of the period detection unit 110, and SC3 corresponds to the operation of the pulsation timing detection unit 112.

  Thus, according to the present embodiment, the ultrasonic probe 24 that radiates ultrasonic waves to the blood vessel 20 and receives the reflected signal of the ultrasonic waves, and the direction of the ultrasonic probe 24 with respect to the blood vessel 20 The reflected signal received by the ultrasonic probe 24 corresponding to each direction of the ultrasonic probe 24 changed by the probe direction control unit 102 (SA7 and SA8) that changes the probe direction and the probe direction control unit 102 The time-series waveform detection unit 100 (SA1 to SA6) for detecting the time-series waveform of the change amount in the radial direction of the blood vessel 20 based on the above, and each direction of the ultrasonic probe 24 detected by the time-series waveform detection unit 100 The deflection method for detecting the direction of the ultrasonic probe 24 in which the amount of change in the radial direction of the blood vessel 20 is the largest from the time-series waveform corresponding to Since the detection unit 104 (SC2) is provided, even when the manner of change of the blood vessel 20 is deflected due to the tissue such as the surrounding muscle 70 or the restraint by the ultrasonic probe 24, etc. The change in the diameter of the blood vessel 20 can be suitably measured. That is, it is possible to provide the measuring device 22 that suitably detects the pulsation timing of the blood vessel 20.

  A period detector 110 (SC2) for detecting a period of the time series waveform detected by the time series waveform detector 100 corresponding to the direction of the ultrasonic probe 24 detected by the deflection direction detector 104; Since the pulsation timing detection unit 112 (SC3) for detecting the pulsation timing of the blood vessel 20 based on the period of the time-series waveform detected by the cycle detection unit 110 is provided, the blood vessel 20 Even when the manner of change is deflected due to tissue such as the surrounding muscle 70 or restraint by the ultrasonic probe 24, the pulsation timing of the blood vessel 20 can be detected in a suitable and practical manner. .

  A frame setting unit 106 (SB1 and SB2) for setting a frame corresponding to a predetermined time interval in the time series waveform detected by the time series waveform detection unit 100, and the frame set by the frame setting unit 106 And an intra-frame waveform acquisition unit (SC1) that acquires the time-series waveform included in the frame at each shift, and the period detection unit 110 includes the intra-frame waveform acquisition unit. Since the autocorrelation function of the time series waveform included in each frame acquired by 108 is calculated and the period of the time series waveform is detected based on the calculated autocorrelation function, the beat of the blood vessel 20 is detected. The motion timing can be detected in a suitable and practical manner.

  The period detection unit 110 calculates an autocorrelation function gradient of a time-series waveform included in each frame acquired by the intra-frame waveform acquisition unit 108, and based on the calculated autocorrelation function gradient, Since the period of the series waveform is detected, the pulsation timing of the blood vessel 20 can be detected in a suitable and practical manner.

  The period detection unit 110 calculates a gradient of an autocorrelation function of a time-series waveform included in each frame acquired by the intra-frame waveform acquisition unit 108, and calculates the gradient of the gradient calculated corresponding to each frame. Since the period of the time series waveform is detected based on the average of the sum, the pulsation timing of the blood vessel 20 can be detected in a suitable and practical manner.

  The preferred embodiments of the present invention have been described in detail with reference to the drawings. However, the present invention is not limited to these embodiments, and various modifications can be made without departing from the spirit of the present invention. Is.

10: sensor holder, 12: probe unit, 14: living body, 16: upper arm, 18: skin, 20: blood vessel, 22: biological blood vessel state measuring device, 24: ultrasonic probe, 24a: ultrasonic wave for first short axis Array probe, 24b: ultrasonic array probe for second short axis, 24c: ultrasonic array probe for long axis, 26: multi-axis drive device, 28: electronic control device, 30: monitor screen display device , 32: ultrasonic drive control circuit, 34: triaxial drive motor control circuit, 36: magnet base, 38: unit fixture, 40: universal arm, 42: tip, 44, 45: connecting member, 46, 47: Link, 48: Fitting hole, 50, 51: Curved joint, 52: Fixed knob, 54: Rotating joint, 58: Air pump, 60: Pressure control valve, 62: Cuff, 64: Pressure sensor, 66 : Boundary, 68: endothelium, 70: muscle, 8 : Ultrasonic drive control unit, 82: detection processing unit, 84: ultrasonic signal processing unit, 86: triaxial drive motor control unit, 88: cuff pressure control unit, 90: blood vessel state evaluation unit, 92: display control unit, 100: time series waveform detection unit, 102: probe direction control unit, 104: deflection direction detection unit, 106: frame setting unit, 108: intra-frame waveform acquisition unit, 110: period detection unit, 112: pulsation timing detection unit, G1: first short axis image display area, G2: second short axis image display area, G3: long axis image display area, L ₁ : intima, L ₂ : media, L ₃ : outer film

Claims (5)

A biological blood vessel state measuring device that radiates ultrasonic waves to a blood vessel located in the epidermis of a living body and measures the state of the blood vessel based on a reflected signal of the ultrasonic wave,
A probe that emits ultrasonic waves to the blood vessel and receives a reflected signal of the ultrasonic waves;
A probe direction controller that changes the direction of the probe relative to the blood vessel;
Time-series waveform detection for detecting a time-series waveform of a change amount in the radial direction of the blood vessel based on the reflected signal received by the probe corresponding to each direction of the probe changed by the probe direction control unit And
A deflection direction detection unit that detects the direction of the probe in which the amount of change in the radial direction of the blood vessel is the largest from the time series waveform corresponding to each direction of the probe detected by the time series waveform detection unit; A biological blood vessel state measuring device comprising: A period detector that detects a period of the time-series waveform detected by the time-series waveform detector corresponding to the direction of the probe detected by the deflection direction detector;
The biological blood vessel state measuring device according to claim 1, further comprising a pulsation timing detection unit that detects a pulsation timing of the blood vessel based on a period of the time-series waveform detected by the cycle detection unit. . A frame setting unit for setting a frame corresponding to a predetermined time interval in the time series waveform detected by the time series waveform detection unit;
An intra-frame waveform acquisition unit that shifts the frame set by the frame setting unit in a time direction and acquires the time-series waveform included in the frame at each shift, and
The period detection unit calculates an autocorrelation function of a time series waveform included in each frame acquired by the intra-frame waveform acquisition unit, and detects a period of the time series waveform based on the calculated autocorrelation function The biological blood vessel state measuring device according to claim 2. The period detector calculates a gradient of an autocorrelation function of a time-series waveform included in each frame acquired by the intra-frame waveform acquisition unit, and the time-series waveform based on the calculated gradient of the autocorrelation function The biological blood vessel state measuring device according to claim 3. The period detection unit calculates a gradient of an autocorrelation function of a time series waveform included in each frame acquired by the intra-frame waveform acquisition unit, and calculates a sum of the gradients calculated corresponding to each frame. The biological blood vessel state measuring apparatus according to claim 4, wherein the period of the time series waveform is detected based on an average.

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