JP2009039407A - Ultrasonic diagnosis device, and ultrasonic probe for use in ultrasonic diagnosis device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an arrangement for adjusting the positional relation between an ultrasonic transducer and a blood vessel so that a sound line from the ultrasonic transducer passes through the center of the cross-section of the blood vessel when elastic characteristics are measured. <P>SOLUTION: The ultrasonic diagnosis device comprises: an ultrasonic probe for utilizing a transducer provided with a plurality of vibration elements arrayed in the length direction, transmitting ultrasonic waves and receiving the ultrasonic waves reflected on the tissue of a living body; a transmission part for successively transmitting the ultrasonic waves from different positions along the length direction to the transducer; a reception part for repeatedly receiving the ultrasonic waves reflected on the blood vessel using the transducer and generating a plurality of reception signals; a strength information generation part for generating strength information relating to the strength distribution of reflected waves on the basis of the plurality of reception signals; and a judging section for specifying a position along the length direction when the reflection strength is maximized on the basis of the strength information. The ultrasonic waves are transmitted at the specified position and the property characteristic value of the blood vessel is operated. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an ultrasonic diagnostic apparatus and an ultrasonic probe, and in particular, an ultrasonic diagnostic apparatus and a control method thereof for measuring a property characteristic of a tissue in a living body, a structure of an ultrasonic probe used in the ultrasonic diagnostic apparatus, and It relates to a control method.

  In recent years, an increasing number of people suffer from cardiovascular diseases such as myocardial infarction and cerebral infarction, and it has become a major issue to prevent and treat such diseases. Arteriosclerosis is closely related to the onset of myocardial infarction and cerebral infarction. Therefore, there is a need for a diagnostic method or apparatus for diagnosing the degree of arteriosclerosis at an early stage where arteriosclerosis proceeds.

  Conventionally, arteriosclerotic lesions have been diagnosed by directly observing the inside of a blood vessel using a vascular catheter. However, in this diagnosis, since it is necessary to insert a vascular catheter into the blood vessel, there is a problem that the physical load on the subject is large. For this reason, observation with a vascular catheter is used to identify the location of a subject who is certain that an arteriosclerotic lesion is present. For example, this method can be used as a test for health care. It was never used.

  2. Description of the Related Art Conventionally, an ultrasonic diagnostic apparatus and an X-ray diagnostic apparatus have been used as a non-invasive medical diagnostic apparatus that has less physical burden on a subject. By irradiating ultrasonic waves or X-rays from outside the body, it is possible to obtain shape information in the body or time change information of the shape without causing pain to the subject. When time change information (motion information) of the shape of the measurement object in the body is obtained, the property information of the measurement object can be obtained. For example, the elastic modulus of the blood vessel is obtained based on a minute change in the thickness of the blood vessel superimposed on the large-amplitude displacement motion caused by the heartbeat, that is, the amount of distortion of the blood vessel and the blood pressure difference. Therefore, by obtaining exercise information, it is possible to determine the elastic characteristics of the blood vessels in the living body and directly know the degree of arteriosclerosis.

  In particular, ultrasound diagnosis is superior to X-ray diagnosis in that it can be measured simply by placing an ultrasound probe on the subject, so that it does not require contrast agent administration to the subject and there is no risk of X-ray exposure. Yes.

  Recent advances in electronics technology have made it possible to dramatically improve the measurement accuracy of ultrasonic diagnostic equipment. Along with this, development of ultrasonic diagnostic apparatuses that measure minute movements of living tissues is progressing. It is possible to measure in detail the two-dimensional distribution of the elastic characteristics of the arterial wall by measuring the minute movement of the living tissue with high accuracy.

  For example, Patent Document 1 discloses a technique for tracking a measurement target with high accuracy by analyzing the amplitude and phase of an ultrasonic echo signal using a constrained least square method. This technique is called a phase difference tracking method. According to this technique, an amplitude due to vascular motion is several microns, and a fast vibration component having a frequency up to several hundred Hz can be measured with high accuracy. For this reason, it has been reported that it is possible to measure the thickness change and distortion of the blood vessel wall with high accuracy on the order of several microns.

  Patent Document 2 discloses a technique for measuring a blood vessel elastic modulus for each scanning section by defining a plurality of scanning sections for a subject and scanning with ultrasonic waves.

  On the other hand, the ultrasonic diagnostic apparatus of Patent Document 3 uses an index for determining whether or not a subject has arteriosclerosis based on a blood vessel characteristic different from the elastic characteristic, specifically a value indicating the thickness of the carotid artery. As measured. It is known that the carotid artery has a structure having three layers of an intima, a media, and an outer membrane in order from the inside. The ultrasonic diagnostic apparatus of Patent Document 3 measures the value of the combined thickness of the intima and media (hereinafter referred to as IMT thickness: hereinafter referred to as IMT).

In addition, since the ultrasonic diagnostic apparatus of Patent Document 3 does not have a means for measuring the displacement (distortion) of the blood vessel 3, it cannot measure the elastic characteristics of the blood vessel. In addition, this ultrasonic diagnostic apparatus must have a function for displaying the IMT value in a three-dimensional manner before the measurement, which requires time for processing and increases in cost.
Japanese Patent Laid-Open No. 10-5226 Japanese Patent Laid-Open No. 2001-292995 JP 2006-045656 A

  In order to accurately measure the elastic characteristics of a blood vessel, accurate time change information (motion information) regarding the shape of the blood vessel is required. For this purpose, it is necessary to measure the displacement of the blood vessel while the ultrasonic acoustic line passes through the center of the blood vessel cross section.

  For example, (a1) in FIG. 19 is a top view of the probe 100 ideally disposed with respect to the blood vessel 3, and (a2) is a cross-sectional view thereof. An acoustic line of ultrasonic waves output from the transducer 101 provided in the probe 100 passes through the center o of the cross section of the blood vessel 3. In this state, since the direction in which the thickness of the blood vessel 3 changes due to the heartbeat coincides with the direction of the acoustic line, an accurate distortion amount of the blood vessel can be measured. Therefore, an accurate elastic modulus can be measured.

  However, in the conventional ultrasonic diagnostic apparatus, no particular attention has been paid to whether or not the ultrasonic acoustic line passes through the center o of the blood vessel cross section. This is presumed to be based on the assumption that the user of the ultrasonic diagnostic apparatus is proficient in the operation, but it is naturally expected to be used by a user who is not familiar with the operation. Not appropriate.

  It is difficult for a user who is not familiar with the operation to arrange the probe 100 so that the ultrasonic acoustic line passes through the center of the blood vessel cross section. For example, (b1) of FIG. 19 shows a top view of the probe 100 arranged at a position shifted from the center of the blood vessel 3. And (b2) of FIG. 23 shows the sectional view. In this state, since the direction in which the thickness of the blood vessel 3 changes does not match the direction of the acoustic line, it is impossible to measure the exact amount of distortion of the blood vessel.

  The above example shows an example in which the probe 100 is arranged in parallel with the blood vessel 3. However, since the direction of the blood vessel 3 cannot be visually recognized from the outside, the blood vessel 3 may be arranged in a state close to perpendicular to the blood vessel 3. FIGS. 20A and 20B are top views of the probe 100 arranged in a state not parallel to the blood vessel 3. Since the acoustic line from the transducer 101 does not always pass through the center of the blood vessel cross section, it is impossible to measure the exact amount of distortion of the blood vessel.

  Furthermore, the blood vessel 3 does not necessarily extend parallel to the epidermis. When the blood vessel 3 extends from the epidermis in the depth direction in the body, no matter how the probe 100 is arranged in a plane parallel to the epidermis, the acoustic line from the transducer 101 always keeps the center of the cross section of the blood vessel. You will not pass. Then, the exact amount of distortion of the blood vessel cannot be measured.

  In any of the cases described above, it is difficult for a user who is not familiar with the operation of the apparatus to find the center of the blood vessel cross section by a technique while viewing the image. This makes the measured elastic properties inaccurate.

  An object of the present invention is to provide a configuration for adjusting the positional relationship between an ultrasonic transducer and a blood vessel so that an acoustic line from the ultrasonic transducer passes through the center of a blood vessel cross section when measuring elastic properties. That is.

  An ultrasonic diagnostic apparatus according to the present invention transmits an ultrasonic wave using a vibrator having a plurality of vibration elements arranged in a length direction and receives the ultrasonic wave reflected by a living tissue. A transmitter that sequentially transmits ultrasonic waves from different positions along the length direction to the vibrator, and a plurality of ultrasonic waves reflected by the blood vessel are repeatedly received using the vibrator. A reception unit that generates the received signal, an intensity information generation unit that generates intensity information related to the intensity distribution of the reflected wave based on the plurality of received signals, and the reflection intensity is maximized based on the intensity information. A determination unit that specifies a position along the length direction when the error occurs, and transmits the ultrasonic wave at the specified position to calculate a property characteristic value of the blood vessel.

  The ultrasonic probe has a driving device that changes the position of the transducer in the ultrasonic probe, the ultrasonic diagnostic device controls the driving device, and the transducer transmits the ultrasonic wave. A probe control unit that changes a position to be calculated, and a calculation unit that calculates the property characteristic value of the blood vessel, and after the calculation unit measures the property characteristic value of the blood vessel at the specified position, The probe control unit may control the driving device to move the vibrator in a direction perpendicular to the ultrasonic transmission direction and perpendicular to the length direction.

  The transmitter may sequentially transmit ultrasonic waves from different positions along the length direction to the transducer after movement.

  An ultrasonic diagnostic apparatus according to the present invention includes a transducer that transmits ultrasonic waves and receives the ultrasonic waves reflected by a living tissue, and the ultrasonic probe having a drive device that changes the angle of the transducer; A probe control unit that controls the driving device to change a direction in which the ultrasonic waves are transmitted; a transmission unit that transmits ultrasonic waves to the vibrator; and the ultrasonic waves that are reflected by the blood vessels. A reception unit that generates a reception signal; an intensity information generation unit that generates intensity information related to the reflection intensity of the reflected wave based on the reception signal; and the reflection intensity is maximized based on the intensity information. A determination unit for specifying an angle at the time of transmission, and calculating the property characteristic value of the blood vessel by transmitting the ultrasonic wave at the specified angle.

  Before and after the probe control unit changes the angle of the transducer, the transmission unit causes the transducer to transmit the ultrasonic wave, and the reception unit corresponds to each transmitted ultrasonic wave. A reception signal is generated, and the intensity information generation unit generates intensity information indicating the reflection intensity of the reflected wave based on each reception signal, and the probe control unit changes the angle of the transducer The angle of the vibrator may be changed until the later reflection intensity becomes smaller than the reflection intensity before the angle of the vibrator is changed.

  The vibrator has a plurality of vibration elements arranged in a length direction, and after the angle at which the reflection intensity becomes maximum is specified by the determination unit, the transmission unit In contrast, ultrasonic waves are sequentially transmitted from different positions along the length direction, and the receiving unit repeatedly receives the ultrasonic waves reflected by the blood vessel using the vibrator, and receives a plurality of received signals. The intensity information generation unit generates intensity information related to the intensity distribution of the reflected wave based on the plurality of received signals, and the determination unit determines the maximum reflection intensity based on the intensity information. The position along the length direction at the time of becoming may be specified, and the ultrasonic characteristic may be transmitted at the specified position to calculate the property characteristic value of the blood vessel.

  The ultrasonic diagnostic apparatus may further include a display unit for displaying the measured characteristic property value of the blood vessel.

  An ultrasonic diagnostic apparatus according to the present invention transmits an ultrasonic wave using a vibrator having a plurality of vibration elements arranged in a length direction and receives the ultrasonic wave reflected by a living tissue. A transmitter that sequentially transmits ultrasonic waves from different positions along the length direction to the vibrator, and a plurality of ultrasonic waves reflected by the blood vessel are repeatedly received using the vibrator. A reception unit that generates the received signal, a calculation unit that calculates the distortion amount of the blood vessel based on each of the plurality of reception signals, and the length direction when the distortion amount becomes maximum A determination unit for specifying a position, and the calculation unit calculates a property characteristic value of the blood vessel other than the amount of distortion of the blood vessel based on the ultrasonic wave received at the specified position.

  The ultrasonic diagnostic apparatus of the present invention sequentially transmits ultrasonic waves from different positions of the vibrator along the length direction to acquire the reflection intensity of the received signal. And the determination part of an ultrasonic diagnosing device specifies the position of the vibrator | oscillator when a reflection intensity becomes the maximum based on the intensity | strength information which shows the intensity | strength of a reflected wave. This makes it possible to adjust the positional relationship between the ultrasonic transducer and the blood vessel so that the acoustic line from the ultrasonic transducer passes through the center of the blood vessel cross section when measuring the elastic characteristics. Then, by calculating the elastic characteristic of the blood vessel at that position, the accurate elastic characteristic of the blood vessel can be obtained.

  Hereinafter, an embodiment of an ultrasonic diagnostic apparatus according to the present invention will be described with reference to the accompanying drawings.

  FIG. 1 is a block diagram showing a configuration for measuring the elastic characteristics of the blood vessel 3 using the ultrasonic diagnostic apparatus 11. This configuration is common in each embodiment.

  The ultrasonic probe 13 is supported in close contact with the body surface 2 of the subject, and transmits ultrasonic waves (acoustic rays) to the inside of the body tissue including the extravascular tissue 1 and the blood vessel 3 using one or a plurality of ultrasonic vibration elements. To do. The extravascular tissue 1 is composed of fat, muscle, and the like. The transmitted ultrasonic wave is reflected and scattered by the blood vessel 3 and the blood 5, and a part thereof returns to the ultrasonic probe 13 and is received as an echo.

  The ultrasonic probe 13 includes a plurality of ultrasonic vibration elements arranged in an array. In the embodiment described later, the characteristic structure and operation of the ultrasonic probe 13 according to the present invention will be described. Here, the basic operation principle of the ultrasonic probe 13 will be outlined.

  FIG. 2 shows a vibrator 30 having a group of ultrasonic vibration elements incorporated in the ultrasonic probe 13. In the transducer 30, ultrasonic vibration element groups are arranged, for example, along one direction to constitute a so-called 1D array transducer.

  The transducer 30 can scan a predetermined range by transmitting and receiving ultrasonic waves by sequentially oscillating each ultrasonic vibration element. The transducer 30 can also receive the signal reflected at the focal position by superimposing the phases of the ultrasonic waves from the plurality of ultrasonic transducer elements at a predetermined position (focal position). An example of the latter is shown in FIG.

  (A1) and (b1) in FIG. 3 schematically show a focused wave of ultrasonic waves when a focal point is formed using a plurality of ultrasonic vibration elements arranged along the x direction. The focused ultrasonic wave has a predetermined width as shown, and has a focal point at a predetermined depth in the z-axis direction.

  In addition, description may be simplified on this drawing. For example, instead of the focused ultrasonic wave corresponding to FIG. 3 (a1), only the central axis of the ultrasonic beam indicated as “acoustic line” in FIG. 3 (a2) may be described. In addition, instead of the focused ultrasonic wave corresponding to FIG. 3B1, only the central axis of the ultrasonic beam indicated as “acoustic line” in FIG. 3B2 may be described.

  FIG. 4 schematically shows an ultrasonic beam propagating through a living tissue. The ultrasonic transmission wave emitted from the ultrasonic probe 13 travels in the z-axis direction as an ultrasonic beam 67 having a certain finite width, and propagates through the extravascular tissue 1 and the blood vessel 3 of the living tissue 60. Then, a part of the ultrasonic wave reflected or scattered by the extravascular tissue 1 and the blood vessel 3 in the propagation process returns to the ultrasonic probe 13 and is received as an ultrasonic reflected wave. The reflected ultrasonic wave is detected as a time series signal, and the time series signal of reflection obtained from the tissue close to the ultrasonic probe 13 is located closer to the origin on the time axis. The width (beam diameter) of the ultrasonic beam 67 can be controlled by changing the delay time.

As described above, the ultrasonic reflected wave is generated from the extravascular tissue 1, the blood vessel 3, and the blood 5. A plurality of measurement target positions P _n (P ₁ , P ₂ , P ₃ , P _k ... P _n , n is a natural number of 3 or more) on the anterior wall of the blood vessel located on the acoustic line 66 exceed a certain interval. P ₁ , P ₂ , P ₃ , P _k ... P _n are arranged in the order closest to the acoustic probe 13. In FIG. 4, coordinate axes with the upper side being positive and the lower side being negative are provided in the depth direction, and the coordinates of the measurement target positions P ₁ , P ₂ , P ₃ , P _k ... P _n are respectively Z ₁ , Z ₂ , Z ₃ , Z _k ,... Z _n , the reflection from the measurement target position P _k is located at t _k = 2Z _k / c on the time axis. Here, c represents the speed of ultrasonic waves in the body tissue. The reflected wave signal (time series signal) is used as information representing the state of the measurement target position.

  The ultrasonic diagnostic apparatus 11 transmits an ultrasonic wave to the blood vessel 3 to acquire a reflected wave signal before measuring the property characteristic of the blood vessel 3 such as the elastic property or distortion of the blood vessel. Then, the ultrasonic probe 13 or the vibrator is transmitted so that the ultrasonic wave (acoustic ray) transmitted from the vibrator 30 of the ultrasonic probe 13 passes through the center of the cross section of the blood vessel 3 by the method described as the first and second embodiments described later. The positional relationship between 30 and the blood vessel 3 is adjusted.

  When the adjustment of the positional relationship between the two is completed, the ultrasonic diagnostic apparatus 11 transmits the ultrasonic wave again to the inside of the body tissue, and analyzes and calculates the received signal by the received echo. The ultrasonic diagnostic apparatus 11 determines the instantaneous position of the object by the constrained least square method using both the amplitude and the phase of the detection signal by the method disclosed in Patent Document 1, for example, with high accuracy (position (Measurement accuracy of change is about ± 0.2 microns) Phase tracking is performed. As a result, the ultrasonic diagnostic apparatus 11 can measure the movement information of the extravascular tissue 1 and the blood vessel 3, for example, the temporal change of the position and thickness of the minute part on the wall of the blood vessel 3 with sufficient accuracy.

  A blood pressure monitor 12 is connected to the ultrasonic diagnostic apparatus 11, and information related to the blood pressure value of the subject measured by the blood pressure monitor 12 is input to the ultrasonic diagnostic apparatus 11. By using the information regarding the blood pressure obtained from the sphygmomanometer 12, the elastic characteristic of the minute part in the wall of the blood vessel 3 can be obtained.

  An electrocardiograph 22 is connected to the ultrasonic diagnostic apparatus 11. The ultrasound diagnostic apparatus 11 receives an electrocardiogram waveform from the electrocardiograph 22 and uses the electrocardiogram waveform as a trigger signal for determining the timing of acquiring measurement data and resetting data.

  In the following embodiments, an example in which the elasticity characteristic of a blood vessel is obtained using an ultrasonic diagnostic apparatus will be described, but it is also possible to measure a blood vessel property characteristic other than the blood vessel elasticity characteristic, such as a blood vessel distortion. is there.

(Embodiment 1)
Hereinafter, the ultrasonic diagnostic apparatus 11 according to the present embodiment will be described.

  FIG. 5 is a block diagram showing an internal configuration of the ultrasonic diagnostic apparatus 11.

  The ultrasonic diagnostic apparatus 11 includes a transmission unit 14, a reception unit 15, a delay time control unit 16, a phase detection unit 17, a filter unit 18, a calculation unit 19, a calculation data storage unit 20, a display unit 21, an intensity information generation unit 23, A center position determination unit 24 and a probe control unit 25 are provided. Moreover, in order to control each of these components, the control part 26 which consists of a microcomputer etc. is provided.

  Among the components of the ultrasonic diagnostic apparatus 11, the intensity information generation unit 23, the center position determination unit 24, and the probe control unit 25 mainly perform the operation of the transducer 30 and the blood vessel so that the ultrasonic wave passes through the center of the blood vessel cross section. It is provided to adjust the positional relationship. On the other hand, the phase detection unit 17, the filter unit 18, the calculation unit 19, the calculation data storage unit 20, and the display unit 21 are provided mainly for measuring the elastic characteristics of the blood vessel 3 and displaying the measurement results. The transmission unit 14, the reception unit 15, the delay time control unit 16, and the control unit 26 operate in any operation of adjusting the positional relationship between the transducer 30 and the blood vessel and measuring the elastic characteristics of the blood vessel.

  Note that the ultrasonic diagnostic apparatus 11 illustrated in FIG. 5 does not include the ultrasonic probe 13. However, since the ultrasonic probe 13 is essential for the operation of the ultrasonic diagnostic apparatus 11, the ultrasonic probe 13 may be regarded as a component of the ultrasonic diagnostic apparatus 11.

  Hereinafter, the function of each component of the ultrasonic diagnostic apparatus 11 will be described.

  The transmission unit 14 generates a predetermined drive pulse signal and outputs it to the ultrasonic probe 13. The ultrasonic transmission wave transmitted from the ultrasonic probe 13 by the drive pulse signal is reflected and scattered in the body tissue such as the blood vessel 3, and the generated ultrasonic reflected wave is detected by the ultrasonic probe 13. The frequency of the drive pulse for generating the ultrasonic wave is determined in consideration of the depth of the measurement target and the ultrasonic velocity so that the adjacent ultrasonic pulses adjacent on the time axis do not overlap.

  The reception unit 15 detects an ultrasonic reflected wave using the ultrasonic probe 13 and amplifies a signal obtained by the detection, thereby generating a reception signal. The receiver 15 includes an A / D converter, and further converts the received signal into a digital signal. The transmission unit 14 and the reception unit 15 are configured using electronic components.

  The delay time control unit 16 is connected to the transmission unit 14 and the reception unit 15, and controls the delay time of the drive pulse signal given from the transmission unit 14 to the ultrasonic transducer group of the ultrasonic probe 13. Thereby, the direction of the acoustic line of the ultrasonic beam of the ultrasonic transmission wave transmitted from the ultrasonic probe 13 and the depth of focus are changed. Further, by controlling the delay time of the reception signal received by the ultrasonic probe 13 and generated by the receiving unit 15, the aperture diameter can be changed or the focal position can be changed. The output of the delay time control unit 16 is input to the phase detection unit 17.

  The phase detection unit 17 performs phase detection on the reception signal subjected to delay control by the delay time control unit 16 and separates it into a real part signal and an imaginary part signal. The separated real part signal and imaginary part signal are input to the filter unit 18. The filter unit 18 removes a high frequency component, a reflection component other than a measurement target, a noise component, and the like. The phase detection unit 17 and the filter unit 18 can be configured by software or hardware. Thereby, a phase detection signal including a real part signal and an imaginary part signal corresponding to each of a plurality of measurement target positions set in the tissue of the blood vessel 3 is generated.

  The calculation unit 19 performs various calculations. FIG. 6 shows functional blocks that implement the arithmetic processing of the arithmetic unit 19. The calculation unit 19 includes a shape measurement value calculation unit 31 and a property characteristic value calculation unit 32. An electrocardiographic waveform obtained from the electrocardiograph 22 is input to the calculation unit 19 and used as a trigger signal for determining the timing of acquiring measurement data and resetting data. For this purpose, the electrocardiograph 22 can be replaced with another biosignal detection means such as a heart sound meter or a pulse wave meter, and instead of the electrocardiographic waveform, the electrocardiographic waveform or the pulse wave waveform is used as a trigger signal. Is also possible.

  The shape measurement value calculation unit 31 uses the real part signal and the imaginary part signal of the phase detection signal to obtain position displacement amounts (positional time displacement amounts) at a plurality of measurement target positions set inside the tissue of the blood vessel 3. . The position displacement amount can also be obtained in the same manner by obtaining the motion speed of the measurement target position (tracking position) and integrating the motion speed. Then, by obtaining the difference between the position displacement amounts at any two positions selected from a plurality of position displacement amounts, the thickness change amount between the two points can be obtained. When the initial value of the two positions or the initial value of the difference between the positional displacement amounts at the two positions is given, the thickness between the two points can be obtained.

  Note that the two points that define the thickness or the amount of change in thickness do not have to coincide with the measurement target position set inside the tissue of the blood vessel 3. For example, the center position of a plurality of measurement target positions may be used. In this case, it is preferable to average the positional displacement amounts of a plurality of measurement target positions whose centers are obtained, and use the averaged positional displacement amount. In the case of using a plurality of measurement target positions, the position representing the plurality of measurement target positions and the position displacement amount may be obtained by a simple average, may be weighted, or based on the plurality of measurement target positions. Thus, it is only necessary to obtain the two positions and the positional displacement amount at the positions.

  The property characteristic value calculation unit 32 calculates the maximum thickness change amount from the difference between the maximum value and the minimum value of the obtained thickness change amount, and is positioned between two points from the blood pressure data obtained from the sphygmomanometer 12. Obtain the elastic properties of the tissue to be treated.

Specifically, the property characteristic value calculation unit 32 calculates the difference Δhk between the maximum value and the minimum value of the thickness Hk of the target tissue Tk (value at the time of minimum blood pressure), the thickness change amount Dk (t) of the target tissue, Using the pulse pressure Δp which is the difference between the minimum blood pressure value and the maximum blood pressure value, an elasticity index Ek representing the stiffness of the blood vessel in the target tissue Tk is expressed as the following equation.
Ek = Δp × (Δhk / Hk)

  In addition, you may obtain | require the elastic characteristic of one point pinched | interposed by arbitrary two points. However, since the ultrasonic probe 13 used in the present embodiment has a plurality of ultrasonic transducer elements arranged in an array, the elastic characteristics of all locations in an arbitrary region within the tomographic plane are obtained. It is possible to ask.

  Note that the property characteristic value calculation unit 32 is not provided only for obtaining the elastic characteristics, but may calculate, for example, Δhk / H to obtain a strain that is one of the characteristic characteristics of the blood vessel.

  Refer to FIG. 5 again. The display unit 21 maps the obtained maximum thickness variation, strain, or elastic characteristic of the living tissue, and displays a spatial distribution image for each cardiac cycle indicating the spatial distribution of the shape measurement value or the property measurement value. The spatial distribution image may be one-dimensional, two-dimensional or three-dimensional. If the shape measurement value or the property measurement value is displayed in color or tone, the measurement result can be easily grasped.

  At this time, the operator can determine by specifying on the display unit 21 an arbitrary area for which a shape measurement value or a property measurement value is to be obtained. This area is called ROI (abbreviation of Region Of Interest). The ROI is a display for designating a region where the operator wants to obtain a measurement value. While confirming the size and position on the display unit 21, the ROI is passed through an interface unit (not shown) of the ultrasonic diagnostic apparatus 11. It can be set freely.

FIG. 7 schematically shows the blood vessel wall 40 and the ROI 41 shown on the display unit 21. The region defined by the ROI 41 includes tissues other than the blood vessel wall 40. The image of the blood vessel wall 40 is obtained, for example, by modulating the received signal with the luminance corresponding to the amplitude intensity separately from the above-described calculation. FIG. 8 shows the elastic characteristics in the region defined by the ROI 41 of the blood vessel wall 40. The area defined by the ROI 41, for example, the mapped image data _{f (k) 11 ~f (k} ) 65 is arranged in six rows × 5 columns, image data _{f (k) 11 ~f (k} ) 65 Constitutes the spatial distribution image Fk. As described above, the image data f (k) _{11 to} f (k) ₆₅ are shape measurement values such as the maximum thickness change amount of the living tissue or property characteristic values such as strain and elastic characteristics.

  Data such as the amount of positional displacement, thickness change, and elastic characteristics calculated by the calculation unit 19 is stored in the calculation data storage unit 20 shown in FIG. 5 and can be read as needed. Further, data such as the position displacement amount, thickness change amount, and elastic characteristics calculated by the calculation unit 19 are input to the display unit 21, and the data can be visualized as a two-dimensional image or the like. Further, by connecting the display unit 21 and the calculation data storage unit 20, various stored data can be displayed on the display unit 21 as needed. Various data calculated by the calculation unit 19 are output to the display unit 21 and also output to the storage unit 20, thereby saving the data so that the data can be used later while displaying the data in real time. It is preferable. However, only one of the outputs may be performed.

  The intensity information generation unit 23 measures the intensity of the reflected wave (reflection intensity) based on the amplitude of the reception signal subjected to delay control by the delay time control unit 16 and generates intensity information indicating the distribution of the reflection intensity. As will be described later, in the present embodiment, the x-axis of the transducer 30 (for example, FIG. 4) and the axis of the blood vessel 3 along the direction in which the blood vessel 3 extends (hereinafter referred to as “long axis”) are substantially. It is arranged vertically. The intensity information generator 23 generates intensity information by measuring the reflected intensity of the reflected waves of ultrasonic waves sequentially transmitted in the x-axis direction using the transducer 30.

  The transducer 30 moves in the ultrasonic probe 13 in the direction parallel to the body surface and perpendicular to the x-axis direction, that is, the long axis direction of the blood vessel, while generating ultrasonic waves. The intensity information generation unit 23 measures the reflection intensity obtained with the movement of the transducer 30 and generates intensity information.

  The center position determination unit 24 specifies the position of the transducer 30 in the ultrasonic probe 13 when the strongest reflection intensity is obtained based on the intensity information.

  The probe control unit 25 outputs a control signal for controlling the movement of the transducer 30 in the ultrasonic probe 13, which will be described later. For example, the probe control unit 25 controls the movement start and end, the movement direction, and the movement speed of the transducer 30 based on an instruction from the control unit 26. In addition, the probe control unit 25 moves the transducer 30 to the position specified by the center position determination unit 24.

  Hereinafter, the principle of the process for adjusting the positional relationship between the transducer 30 and the blood vessel 3 will be described with reference to FIGS. 9 and 10. According to this processing, since the ultrasonic wave (acoustic ray) transmitted from the transducer 30 passes through the center of the cross section of the blood vessel 3, the elastic characteristic of the blood vessel 3 can be accurately measured.

  In the present embodiment, it is assumed that the x-axis of the transducer 30 (for example, FIG. 9) and the long axis of the blood vessel 3 are arranged substantially perpendicularly. On the other hand, the z axis (for example, FIG. 9) of the transducer 30 and the major axis of the blood vessel 3 do not necessarily have to be perpendicular.

  FIG. 9 shows a transducer 30 that scans in the x-axis direction while generating ultrasonic waves. The vibrator 30 is housed in the case 50.

  Based on the control signal from the transmitter 14, the transducer 30 generates an ultrasonic wave from one end to the other end while generating an ultrasonic wave, for example, as shown in (a1) and (b1) of FIG. Scan direction.

  FIG. 10 shows the reflection intensity distribution of the ultrasonic reflected wave generated by the intensity information generation unit 23 as a result of scanning in the x-axis direction with ultrasonic waves. The horizontal axis is the length direction (x-axis direction) of the transducer 30, and the vertical axis is the reflection intensity. When the reflection intensity is obtained, the center position determination unit 24 specifies the position Xo of the transducer 30 when the maximum reflection intensity Rmax is obtained.

  The position Xo specified by the center position determination unit 24 corresponds to the position where the ultrasonic acoustic line passes through the center of the cross section of the blood vessel 3. The reason is as follows. As the transmitted wave passes through a position farther away from the center of the cross section, the transmitted wave is reflected on the outer wall and the inner wall of the blood vessel 3 at an angle approaching 90 degrees with respect to the incident direction. The detection intensity becomes small. On the other hand, since the ultrasonic wave is reflected in the incident direction on the outer wall and the inner wall of the blood vessel 3 as the ultrasonic transmission wave passes through a position closer to the center o of the cross section, the detection intensity of the reflected wave from the blood vessel 3 becomes larger. Become. When the ultrasonic transmission wave passes through the center o of the cross section, the incident direction and the reflection direction of the ultrasonic wave coincide with each other on the outer wall and the inner wall of the blood vessel 3, so that the detection intensity of the reflected wave is maximized. Therefore, it can be said that the position on the transducer 30 where the ultrasonic wave is transmitted when the reflection intensity is maximum is the position where the ultrasonic wave passes through the center o of the cross section.

  After the position Xo is specified, the transmission unit 14 may measure the elastic characteristic of the blood vessel 3 by transmitting an ultrasonic wave from the position Xo.

  In the above example, the position of the vibrator 30 is fixed. However, by moving the transducer 30 along the long axis direction of the blood vessel 3 and performing the same operation as described above at the position after the movement, the blood vessel 3 can be moved over the length of the blood vessel 3 in the long axis direction within a certain range. While specifying the center position, accurate elastic characteristics can be measured at each position.

  In the present embodiment, an example will be described in which a mechanism for driving the transducer 30 is provided inside the ultrasound probe 13 so that the transducer 30 can move inside the ultrasound probe 13.

  FIGS. 11A and 11B show a physical configuration of the ultrasonic probe 13 according to the present embodiment. (A) is a perspective view, (b) is a top view. The ultrasonic probe 13 includes a rack 110 and a motor 111. The rack 110 is a flat bar provided with teeth, and is physically coupled to the case 50. The rotation shaft of the motor 111 is provided with a pinion and meshes with the teeth of the rack 110. As the motor 111 rotates, the case 50 moves along with the rack 110 in the y-axis direction. Thereby, the movement of the vibrator 30 shown in FIG. 9 is realized. The probe controller 25 controls the supply of electric power for rotating the motor 111 and the rotation speed and rotation time of the motor 111 corresponding to the amount of movement in the y-axis direction.

  FIG. 12 is a flowchart showing a procedure of processing for measuring the elastic characteristic of the blood vessel 3 in the ultrasonic diagnostic apparatus 11 according to the present embodiment. Here, it is assumed that the ultrasonic probe 13 shown in FIGS. 11A and 11B is used.

  In step S1, when the probe control unit 25 sends a control signal to the ultrasonic probe 13, the transducer 30 scans in the x-axis direction while generating an ultrasonic wave. In step S <b> 2, the intensity information generation unit 23 detects the reflected wave of the ultrasonic wave repeatedly transmitted from the transducer 30 and acquires the reflection intensity. By sequentially transmitting ultrasonic waves from one end of the transducer 30 to the other end and receiving reflected waves, a reflection intensity distribution is obtained.

  In the next step S3, the center position determination unit 24 specifies a position on the transducer 30 where the reflection intensity is maximum as a position (center position) where the ultrasonic wave passes through the blood vessel center o.

  In step S4, the control unit 26 instructs measurement of the elastic characteristics of the blood vessel 3 at the center position. Based on this instruction, the phase detection unit 17, the filter unit 18, the calculation unit 19, and the calculation data storage unit 20 operate to measure the elastic characteristics of the blood vessel 3.

  In step S5, the display unit 21 displays a cross-sectional view of the long axis of the blood vessel, and displays the elastic characteristics measured by the calculation unit 19 superimposed on the cross-sectional view.

  In step S6, the probe control unit 25 moves the transducer 30 within the ultrasonic probe 13 by a certain distance in the y-axis direction. For example, when measuring the elastic properties of the blood vessel 3 at five different points, the probe control unit 25 moves the transducer 30 in the ultrasonic probe 13 by y by a distance that is 1/5 of the movable range in the ultrasonic probe 13. Move in the axial direction.

  In step S <b> 7, it is determined whether or not the transducer 30 has reached the end position of the movable range in the ultrasonic probe 13. If not reached yet, the process returns to step S1, and if reached, the process ends.

  Since the position on the vibrator 30 where the reflection intensity is maximum is specified as the center position by the processing in steps S1 to S3 described above, the elastic characteristic of the blood vessel 3 is measured at the center position, so that the accurate distortion of the blood vessel is determined. The amount can be measured. Therefore, an accurate elastic modulus can be measured.

(Embodiment 2)
In the first embodiment, the center of the cross section of the blood vessel 3 is specified, and the transducer 30 is moved along the predetermined axial direction in the ultrasonic probe 13. This is effective when the blood vessel 3 extends parallel to the epidermis.

  In the present embodiment, an ultrasonic probe capable of specifying the center in a cross section perpendicular to the blood vessel 3 even when the blood vessel 3 is not parallel to the epidermis will be described.

  FIGS. 13A and 13B show a configuration example of the ultrasonic probe 13 that vibrates the case 50 like a pendulum with a point K relatively above the case 50 as a support shaft. The spindle is parallel to the body surface. As shown in FIG. 17 to be described later, the rotation of the motor is configured to be transmitted to the support shaft via a transmission mechanism such as a gear or a belt. However, the rotating shaft of the motor may be aligned with the support shaft. Thereby, the transmission direction of the ultrasonic wave transmitted from the transducer 30 can be changed. The probe control unit 25 controls the rotation direction and the rotation angle of the transducer 30. The movable angle in the examples of FIGS. 13A and 13B is assumed to be −90 degrees to 90 degrees. In addition, although the point K which is a spindle was provided in the position away from the body surface, you may provide in the position close | similar to the body surface.

13A shows the vibrator 30 when rotated by an angle θ ₀ (θ ₀ > 0), and FIG. 13B shows the vibrator 30 when the angle is zero. FIGS. 13A and 13B also show the position of the blood vessel 3. In the present embodiment, the blood vessel 3 is not parallel to the epidermis but extends from the epidermis in the depth direction.

  When the ultrasonic probe 13 configured in this way is used, if the rotation angle when the ultrasonic wave transmitted from the transducer 30 passes through the cross-sectional center of the blood vessel 3 is specified based on the maximum reflection intensity, the blood vessel 3 The elastic characteristic of the blood vessel 3 can be measured at the center position in the cross section perpendicular to the line.

  FIG. 14 shows a reflection intensity distribution of the ultrasonic reflected wave generated by the intensity information generation unit 23 when the ultrasonic wave is transmitted while changing the angle of the transducer 30 so as to gradually increase from 0 degrees. The ultrasonic wave may be transmitted once at each angular position.

  At the angle 0, as shown in FIG. 13B, the ultrasonic wave is incident on the blood vessel 3 at an angle that is not perpendicular. Most of the incident ultrasonic waves are reflected on the outer wall and the inner wall of the blood vessel 3 in a direction different from the incident direction, and only a part returns to the incident direction, and the reflection intensity is measured.

The reflection intensity gradually increases from the angle 0 to the angle θ ₀ . It means that the higher the reflection intensity, the more the ultrasonic wave is incident on the blood vessel 3 at an angle closer to the vertical. Therefore, the central position determination unit 24 determines that the vertical position has become closer to vertical when a higher reflection intensity is obtained.

By gradually increasing the angle, the angle θ ₀ (θ ₀ > 0) at which the reflection intensity is maximized is reached. When the reflection intensity becomes maximum, the traveling direction of the ultrasonic wave is orthogonal to the long axis of the blood vessel 3. The reason is as described in the first embodiment with reference to FIG.

In order to determine that the reflection intensity is maximum at the angle θ ₀ , the reflection intensity needs to be measured by tilting the vibrator 30 to an angle larger than the angle θ ₀ . Reflection intensity obtained at larger angles, when it becomes smaller than the reflection intensity when the angle theta _0, the reflection intensity at an angle theta ₀ can be determined to be the maximum.

When the vibrator 30 is swung from the angle 0 state shown in FIG. 13B to the negative angle side opposite to the angle θ ₀ (θ ₀ > 0), the reflection intensity gradually increases. Get smaller. This is because the transmission direction of the ultrasonic waves approaches the blood vessel 3 in parallel. Therefore, the probe control unit 25 sets the direction in which the vibrator 30 is shaken in the reverse direction.

  According to this configuration, since it is not necessary to be aware of the relationship between the angle of the ultrasonic probe 13 and the angle at which the blood vessel 3 extends, an accurate elastic modulus is measured even if a user unaccustomed to the ultrasonic probe 13 uses it. be able to.

In the description of the above-described embodiment, the position where the ultrasonic wave passes through the center of the cross section when the ultrasonic wave vertically enters the blood vessel 3 is specified using the maximum reflection intensity. However, it is possible to specify the center position without using the maximum reflection intensity. For example, by using a so-called 1.5D array transducer shown in FIG. 15, the angle θ ₀ described above can be specified with high accuracy and high speed.

  FIG. 15 shows a vibrator 35 which is a modification of the vibrator 30. The transducer 35 includes two rows of ultrasonic transducer groups 35a and 35b. The ultrasonic transducer groups 35 a and 35 b are arranged along the moving direction (y-axis direction) in the ultrasonic probe 13.

  When the transducer 35 is used, the center position can be specified based on the difference T between the reflection intensity detected in the ultrasonic transducer group 35a and the reflection intensity detected in the ultrasonic transducer group 35b. The principle is as follows.

FIG. 16 shows the relationship between the angle of the transducer 35 and the difference value T of the reflection intensity detected in the ultrasound transducer group 35a and the ultrasound transducer group 35b. When the transducer 35 is swung from the state of the angle 0 shown in FIG. 13B in the direction shown by the angle θ ₀ shown in FIG. 13A, first, the reflection intensity detected in the ultrasonic transducer group 35b is initially set. Starts to gradually increase from zero. Regarding the ultrasonic transducer group 35a, since the ultrasonic transducer group 35a is further away from the blood vessel 3, the reflection intensity from the blood vessel 3 detected by the ultrasonic transducer group 35a is determined by the ultrasonic transducer group 35b. It is weaker than the detected reflection intensity from the blood vessel 3. Therefore, the output difference T initially increases in the positive direction.

  Thereafter, when the reflection intensity of the ultrasonic transducer group 35a starts to increase as the angle of the transducer 30 increases, the output difference T gradually decreases. When the outputs of the ultrasonic transducer groups 35a and 35b become equal, the output difference T becomes zero. When the output difference T is 0, the ultrasonic transducer groups 35a and 35b are arranged symmetrically with respect to the central axis of the blood vessel 3 when viewed from the direction shown in FIG. Therefore, the position of the ultrasonic transducer 35 at this time corresponds to a position perpendicular to the blood vessel.

  According to the method of determining the center position based on the difference of the reflection intensity using the vibrator 35, the processing time is shortened because the peak detection of the reflection intensity as in the method of determining the maximum intensity shown in FIG. 10 is unnecessary. It becomes. Further, when adjusting the angle of the vibrator 35, it is only necessary to confirm whether the signal of the output difference T is positive or negative and determine whether the rotation is positive or negative. For example, the rotation of the vibrator 30 may be controlled in the same direction if positive, and the rotation of the vibrator 30 may be controlled in the opposite direction if negative. In the present embodiment, the difference between the reflection intensities of the ultrasonic transducer groups 35a and 35b is calculated by the intensity information generation unit 23.

  Note that the waveform in FIG. 16 is an example for facilitating understanding, and is not necessarily a straight line, and may be obtained as a curve.

  In the first embodiment, the configuration in which the transducer 30 is moved in parallel to the body surface to change the transmission position of the ultrasonic wave (FIG. 11 and the like) has been described. In the present embodiment, the configuration (FIG. 9) in which the transducer 30 is rotated like a pendulum to change the ultrasonic transmission angle has been described. These configurations can be combined. Thereby, the range which can transmit an ultrasonic wave becomes still wider, and the measurable range can be expanded. In other words, the allowable range of the position where the ultrasonic probe 13 is applied to the body surface is widened.

  FIG. 17 shows a physical configuration of the ultrasonic probe 13 that can move in the y-axis direction and can rotate about the x-axis. Among the constituent elements of the ultrasonic probe 13 according to the present embodiment, the same constituent elements as those in the ultrasonic probe shown in FIGS. 11A and 11B are denoted by the same reference numerals, and description thereof is omitted.

  In contrast to the ultrasonic probe according to the first embodiment, the ultrasonic probe 13 according to the present embodiment rotates the case 50 including the vibrator 30 like a pendulum by the motor 111 around a support shaft parallel to the x-axis. be able to. A rack 110 and a motor 111 shown in FIG. 11 are realized by a rack 112 and a motor 113 in FIG.

  In the present embodiment, the case 50 is connected to the rack 112. Moreover, the case 50 is connected so that it can rotate with respect to the spindle to which the power of the motor 111 is transmitted. It is assumed that the case 50, the rack 112, and the motor 113 are driven together during rotation. The rotation of the motor 111 and the rotation of the motor 113 are independently controlled based on a control signal from the probe control unit 25.

  FIG. 18 is a flowchart showing a processing procedure for measuring the elastic characteristics of the blood vessel 3 in the ultrasonic diagnostic apparatus 11 according to the present embodiment.

  First, in step S10, when the transducer 30 exists at a certain position in the y-axis direction, when the probe control unit 25 sends a control signal to the ultrasonic probe 13, the motor 111 generates ultrasonic waves while generating ultrasonic waves. The vibrator 30 is moved in a pendulum manner within the probe.

  In step S11, the intensity information generation unit 23 detects the reflected wave of the ultrasonic wave transmitted during the pendulum movement from one rotation end (+90 degrees) to the other rotation end (−90 degrees), for example, and the reflection intensity. Get the distribution.

  In step S <b> 12, the center position determination unit 24 specifies the angle of the transducer with the maximum reflection intensity as the angle at which the ultrasonic wave passes vertically through the blood vessel. Thereafter, when the control unit 26 instructs execution of the same processing as steps S1 to S4 in FIG. 12, the phase detection unit 17, the filter unit 18, the calculation unit 19, and the calculation data storage unit 20 operate and are perpendicular to the blood vessel. The center position in a simple cross section is selected, and the elastic characteristic of the blood vessel 3 at the center position is measured.

  In step S <b> 13, the display unit 21 displays a cross-sectional view of the blood vessel long axis, and displays the elastic characteristics measured by the calculation unit 19 in a superimposed manner on the cross-sectional view.

  In step S14, the probe control unit 25 moves the transducer by a predetermined distance in the blood vessel major axis direction (y-axis direction) while generating ultrasonic waves.

  In step S15, the probe control unit 25 determines whether or not the transducer has reached the end position. If not reached yet, the process returns to step S10, and if reached, the process ends.

  The ultrasonic wave is adjusted to be perpendicular to the blood vessel by the above-described processing in steps S10 to S12. Furthermore, since the position on the transducer 30 where the reflection intensity is maximum is specified as the center position by the processing in steps S1 to S3 described above, the elastic characteristic of the blood vessel 3 is measured at the center position. The amount of distortion can be measured. Therefore, an accurate elastic modulus can be measured.

  In the above-described processing procedure, the transducer 30 is first moved in a pendulum manner to adjust the ultrasonic wave to be perpendicular to the blood vessel, and then the transducer 30 is moved in the blood vessel long axis direction. However, this order is an example. For example, the vibrator 30 may be moved in a pendulum motion at each position while moving the vibrator 30 in the direction of the blood vessel long axis, and the ultrasonic wave may be adjusted to be perpendicular to the blood vessel each time.

  In the first and second embodiments, a position (center position) on the transducer 30 where the reflection intensity is maximum is specified, and an acoustic line from the position passes through the center of the short-axis cross section of the blood vessel 3, and the center position. It is assumed that the elastic characteristics of the blood vessel 3 are measured.

  However, a method that does not directly use the reflection intensity is also conceivable. For example, the reflected wave is received by scanning in the x-axis direction while generating an ultrasonic wave from the transducer 30, and the thickness of the vascular tissue is obtained using the property characteristic value calculation unit 32 based on the obtained reflected wave. Measure the amount of distortion. The center position determination unit 24 receives the measurement result of the distortion amount, and specifies the position along the length direction of the transducer 30 when the distortion amount is maximized. It can be said that the acoustic line passes through the center of the short-axis cross section of the blood vessel 3 when the distortion amount is maximized. The reason is as follows. As the distance from the center increases, the thickness distortion gradually decreases, and the reflection intensity on the upper and lower surfaces of the thickness also decreases accordingly. At the end of the blood vessel, there is no reflection on the upper and lower surfaces of the thickness. In a range where there is sufficient reflection from the center to the upper and lower surfaces of the thickness, it is considered that the thickness distortion due to the acoustic line passing through the center is maximized. As a result, the position specified by the above-described processing becomes the above-described center position. The property characteristic value calculation unit 32 may measure the elastic characteristic of the blood vessel 3 at the center position.

  The procedure of the process according to the above-described method for measuring the distortion of the vascular tissue thickness is the same as the process procedure of the first embodiment except, for example, steps S3 and S4 in FIG. Specifically, instead of step S3 in FIG. 12, the property characteristic value calculation unit 32 may perform a process of measuring the distortion of the vascular tissue based on each reflected wave. In place of step S4, the center position determination unit 24 specifies the position when the strain of the vascular tissue becomes maximum as the center position, and the property characteristic value calculation unit 32 receives the ultrasonic wave received at the center position. The elastic characteristic of the blood vessel 3 may be measured based on the reflected wave.

  As a result, in step S5, the elastic characteristic at the center position is displayed. Note that after the center position is specified, ultrasonic waves may be transmitted and received again, or the elastic characteristics may be measured based on the received wave already obtained. In addition, although Embodiment 1 was demonstrated to the example, the above-mentioned process is applicable also to the process of Embodiment 2.

  In the first and second embodiments, the transducer 30 is moved in the ultrasonic probe 13 by a so-called rack and pinion method, but this is an example. The movement and rotation of the case 50 and the vibrator 30 may be controlled by connecting the motor 111 and / or the motor 113 and the case 50 with a belt and winding or feeding the belt by the rotation of the motor. Also, the type of motor that is the driving device is arbitrary, and for example, a linear motor or a voice coil motor may be used. It is easy for those skilled in the art to change the structure in the ultrasonic probe 13 for moving the transducer 30 according to the driving method of the motor to be used.

  Note that a switch (not shown) may be provided on the probe or the main body of the ultrasonic diagnostic apparatus so as to switch whether or not to move and / or rotate the transducer in the ultrasonic probe. If the operator is proficient in using the probe, it can be said that the measurement result of the elastic characteristic can be said to be accurate by looking at the displayed elastic characteristic image, that is, the probe is properly arranged, and the blood vessel is This is because it can be easily determined whether or not the elastic property is measured. By switching whether or not the center position determination process is performed, the ultrasonic diagnostic apparatus can be operated according to the level of proficiency of the user, and convenience can be improved.

  Among the processes for specifying the center position described with reference to FIGS. 10 and 16, the process of acquiring the reflection intensity by moving the transducer 30 is performed by other measurements, for example, the shape measurement of the blood vessel 3 or the blood vessel 3. It can also be used to measure the diameter of This means that the center position of the blood vessel can be specified from the measured shape. When used for the process of measuring the shape of the blood vessel 3, the shape data is acquired by accumulating data of a plurality of cross-sectional shapes along the long axis of the blood vessel 3. The shape data may include a change in the thickness of the front wall of the blood vessel 3 in which the blood vessel 3 changes due to a heartbeat. The process of measuring the diameter of the blood vessel 3 calculates the difference between the reflected wave from the wall near the ultrasonic probe 13 of the blood vessel 3 and the reflected wave from the far wall at the center position described so far. Is executed by. If the process for obtaining the above-described reflection intensity is executed in advance when the ultrasonic probe 13 is applied to the body surface of the subject, the subsequent process can be performed quickly.

  The ultrasonic diagnostic apparatus of the present invention is suitably used for measuring the property and shape characteristics of a living tissue, and is suitable for measuring an accurate elastic characteristic. In addition, the elastic characteristics of the blood vessel wall are measured, and the blood vessel wall is suitably used for finding an arteriosclerotic lesion or preventing arteriosclerosis.

2 is a block diagram showing a configuration for measuring elastic properties of a blood vessel 3 using an ultrasonic diagnostic apparatus 11. FIG. FIG. 3 is a diagram showing an ultrasonic transducer group 30 built in the ultrasonic probe 13. (A1) and (b1) are schematic diagrams of an ultrasonic focused wave when a focal point is formed using a plurality of ultrasonic transducer elements arranged along the x direction, and (a2) and (b2) are It is a simplified diagram of an ultrasonic focused wave. It is a figure which shows typically the ultrasonic beam which propagates the structure | tissue of a biological body. 2 is a block diagram showing an internal configuration of an ultrasonic diagnostic apparatus 11. FIG. 3 is a block diagram illustrating an internal configuration of a calculation unit 19. FIG. 4 is a schematic diagram of a blood vessel wall 40 and an ROI 41 shown on the display unit 21. FIG. It is a figure which shows the elastic characteristic in the area | region prescribed | regulated by ROI41 of the blood vessel wall. It is a figure which shows the vibrator | oscillator 30 which scans an x-axis direction, producing | generating an ultrasonic wave. It is a figure which shows distribution of the reflected intensity of the ultrasonic reflected wave which the intensity | strength information generation part 23 produced | generated as a result of scanning the x-axis direction with the ultrasonic wave. (A) And (b) is a figure which shows the physical structure of the ultrasonic probe 13 by this embodiment. 4 is a flowchart showing a procedure of processing for measuring elastic properties of a blood vessel 3 in the ultrasonic diagnostic apparatus 11 according to the first embodiment. (A) And (b) is a figure which shows the structural example of the ultrasonic probe 13 which vibrates the case 50 like a pendulum by using the comparatively upper point K of the case 50 as a spindle. It is a figure which shows distribution of the reflected intensity of the ultrasonic wave which the intensity | strength information generation part 23 produced | generated when an ultrasonic wave was transmitted changing the angle of the ultrasonic probe 13 so that it may become large gradually from 0 degree | times. FIG. 6 is a diagram illustrating a vibrator 35 that is a modification of the vibrator 30. It is a figure which shows the relationship between the angle of the transducer | vibrator 35, and the difference value T of the reflection intensity detected in the ultrasonic transducer | vibrator group 35a and the ultrasonic transducer | vibrator group 35b. It is a figure which shows the physical structure of the ultrasonic probe 13 which can move to a y-axis direction, and can rotate centering on an x-axis. 6 is a flowchart showing a procedure of processing for measuring elastic characteristics of a blood vessel 3 in the ultrasonic diagnostic apparatus 11 according to the second embodiment. (A1) and (a2) are a top view and a cross-sectional view of the probe 100 ideally arranged with respect to the blood vessel 3, and (b1) and (b2) are arranged at positions shifted from the center of the blood vessel 3. 2 is a top view and a cross-sectional view of the probe 100. FIG. (A) And (b) is a top view of the probe 100 arrange | positioned in the state which is not parallel to the blood vessel 3. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Extravascular tissue 2 Body surface 3 Blood vessel 4 Blood vessel front wall 5 Blood 11 Ultrasound diagnostic device 12 Sphygmomanometer 13 Ultrasonic probe 14 Transmitter 15 Receiver 16 Delay time controller 17 Phase detector 18 Filter 19 Calculator 19 Calculator 20 Data storage unit 21 Display unit 22 Electrocardiograph 23 Intensity information generation unit 24 Center position determination unit 25 Probe control unit 26 Control unit 30, 35 Transducer 31 Shape measurement value calculation unit 32 Property characteristic value calculation unit 40 Blood vessel wall 41 ROI
50 Case 110, 112 Rack 111, 113 Motor

Claims (8)

An ultrasonic probe that transmits an ultrasonic wave using a vibrator having a plurality of vibration elements arranged in a length direction and receives the ultrasonic wave reflected by a living tissue; and
A transmitter that sequentially transmits ultrasonic waves from different positions along the length direction to the vibrator;
A reception unit that repeatedly receives the ultrasonic wave reflected by the blood vessel using the vibrator and generates a plurality of reception signals;
An intensity information generating unit that generates intensity information related to the intensity distribution of the reflected wave based on the plurality of received signals;
A determination unit that specifies a position along the length direction when the reflection intensity becomes maximum based on the intensity information, and transmits the ultrasonic wave at the specified position to An ultrasonic diagnostic apparatus that calculates property characteristic values. The ultrasonic probe has a driving device that changes the position of the vibrator in the ultrasonic probe,
The ultrasonic diagnostic apparatus comprises:
A probe controller that controls the driving device to change the position at which the transducer transmits the ultrasonic wave; and
A calculation unit that calculates the property characteristic value of the blood vessel,
After the arithmetic unit measures the property characteristic value of the blood vessel at the specified position, the probe control unit controls the driving device to be perpendicular to the ultrasonic transmission direction and to the transducer. The ultrasonic diagnostic apparatus according to claim 1, wherein the ultrasonic diagnostic apparatus is moved in a direction perpendicular to the length direction.   The ultrasonic diagnostic apparatus according to claim 2, wherein the transmission unit sequentially transmits ultrasonic waves from different positions along the length direction to the vibrator after movement. A transducer that transmits ultrasonic waves and receives the ultrasonic waves reflected by the tissue of the living body, and the ultrasonic probe having a drive device that changes the angle of the transducers;
A probe controller that controls the driving device to change the direction in which the ultrasonic waves are transmitted; and
A transmitter that transmits ultrasonic waves to the vibrator;
A receiver that receives the ultrasound reflected by the blood vessel and generates a received signal;
An intensity information generating unit that generates intensity information related to the reflected intensity of the reflected wave based on the received signal;
A determination unit that specifies an angle when the reflection intensity is maximized based on the intensity information, and calculates the property characteristic value of the blood vessel by transmitting the ultrasonic wave at the specified angle. Ultrasonic diagnostic equipment. Before and after the probe control unit changes the angle of the vibrator,
The transmitting unit transmits the ultrasonic waves to the vibrator,
The receiving unit generates each received signal corresponding to each transmitted ultrasonic wave,
The intensity information generation unit generates intensity information indicating the reflection intensity of the reflected wave based on each received signal,
The probe control unit changes the angle of the vibrator until the reflection intensity after changing the angle of the vibrator becomes smaller than the reflection intensity before changing the angle of the vibrator. 4. The ultrasonic diagnostic apparatus according to 4. The vibrator has a plurality of vibration elements arranged in a length direction,
After the angle when the reflection intensity is maximized by the determination unit is specified,
The transmitter causes the transducer to sequentially transmit ultrasonic waves from different positions along the length direction,
The receiving unit repeatedly receives the ultrasonic wave reflected by the blood vessel using the vibrator to generate a plurality of reception signals,
The intensity information generation unit generates intensity information related to the intensity distribution of the reflected wave based on the plurality of received signals,
The determination unit specifies a position along the length direction when the reflection intensity is maximum based on the intensity information,
The ultrasonic diagnostic apparatus according to claim 5, wherein the ultrasonic characteristic is calculated by transmitting the ultrasonic wave at the specified position.   The ultrasonic diagnostic apparatus according to claim 1, further comprising a display unit for displaying the measured characteristic property value of the blood vessel. An ultrasonic probe that transmits an ultrasonic wave using a vibrator having a plurality of vibration elements arranged in a length direction and receives the ultrasonic wave reflected by a living tissue; and
A transmitter that sequentially transmits ultrasonic waves from different positions along the length direction to the vibrator;
A reception unit that repeatedly receives the ultrasonic wave reflected by the blood vessel using the vibrator and generates a plurality of reception signals;
Based on each of the plurality of received signals, a calculation unit that calculates the distortion amount of the blood vessel;
A determination unit that specifies a position along the length direction when the distortion amount is maximized, and the calculation unit is configured to determine the blood vessel based on the ultrasonic wave received at the specified position. An ultrasonic diagnostic apparatus that calculates a property characteristic value of the blood vessel other than the amount of distortion.

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