JP2006230618A - Ultrasonic diagnostic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ultrasonic diagnostic apparatus capable of precisely measuring the properties and characteristics of a subject. <P>SOLUTION: The ultrasonic diagnostic apparatus comprises a transmission part 102 for generating a driving signal for driving a probe 101 to transmit ultrasonic waves to the subject, a receiving part 103 for receiving an echo obtained from the reflection of the ultrasonic waves on the subject by the probe 102 and amplifying the received echo signal, capable of changing the gain to amplify the received echo signal, a storage part 110 for storing the maximum value of the received echo signal, and an adjusting part 111 for adjusting at least either the gain of the receiving part 103 or the driving signal generated by the transmission part 102 by synchronizing with the cycle of deformation of the subject based on the maximum value stored in the storage part 110. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an ultrasonic diagnostic apparatus, and more particularly, to an ultrasonic diagnostic apparatus that measures a property characteristic of a tissue constituting a subject.

  The ultrasonic diagnostic apparatus irradiates a subject with ultrasonic waves and analyzes information included in the echo signal to inspect the subject non-invasively. 2. Description of the Related Art Conventionally, an ultrasonic diagnostic apparatus that has been widely used obtains the structure of a subject as a tomographic image by converting the intensity of an echo signal into the luminance of a corresponding pixel. Thereby, the internal structure of the subject can be known.

  On the other hand, in recent years, by analyzing mainly the phase of the echo signal, the movement of the tissue of the subject is accurately measured, and physical (property) characteristics such as tissue distortion, elastic modulus, and viscosity are obtained. Has been tried.

  Patent Document 1 uses the amplitude and phase of the detection output signal of the echo signal to determine the instantaneous position of the subject, thereby tracking the subject tissue with high accuracy and applying it to the beating heart tissue. A method for capturing the minute vibrations that occur is disclosed. This method is called a phase difference tracking method. According to this method, ultrasonic pulses are transmitted a plurality of times at intervals of ΔT in the same direction to the subject, and the ultrasonic waves reflected by the subject are received. As shown in FIG. 7, it is assumed that the received echo signals are y (t), y (t + ΔT), and y (t + 2ΔT). The reception time t1 of the echo signal obtained from a certain depth x1 is t1 = x1 / (C / 2), where the pulse transmission time is t = 0. Where C is the speed of sound. At this time, if the phase displacement between y (t1) and y (t1 + ΔT) is Δθ, and the center frequency of the ultrasonic wave near t1 is f, the movement amount Δx of x1 in this period ΔT is expressed by the following equation. Is done.

  Δx = −C · Δθ / 4πf

  By adding the movement amount Δx to x1, as shown below, the position x1 ′ of x1 after ΔT seconds can be obtained. By repeating this calculation, the same part x1 of the subject is tracked. be able to.

  x1 '= x1 + Δx

  Patent Document 2 discloses a method of further developing the method of Patent Document 1 and obtaining the elastic modulus of a subject tissue, particularly an arterial wall. According to this method, first, as shown in FIG. 8A, an ultrasonic wave is transmitted from the probe 101 toward the arterial blood vessel wall, and echo signals from the measurement points A and B set on the blood vessel wall are transmitted. Is analyzed by the method of Patent Document 1 to track the movement of the measurement points A and B. FIG. 8B shows waveforms TA and TB indicating the positions of the measurement points A and B. An electrocardiographic waveform ECG is also shown.

  As shown in FIG. 8B, the tracking waveforms TA and TB have a periodicity that matches the electrocardiogram waveform ECG. This indicates that the artery expands and contracts in line with the heart cycle of the heart. Specifically, when a large peak called an R wave is seen in the electrocardiogram waveform ECG, the contraction of the heart starts, and blood is pushed out into the artery by the contraction of the heart. For this reason, a blood vessel wall spreads rapidly by blood flow. Therefore, after the R wave appears in the electrocardiogram waveform ECG, the tracking waveforms TA and TB also rise rapidly, and the artery expands rapidly. Thereafter, as the heart expands slowly, the tracking waveforms TA and TB also gradually fall, and the artery contracts slowly. The artery repeats this movement.

  The difference between the tracking waveforms TA and TB is a thickness change waveform W between the measurement points AB. If the amount of change in the thickness change waveform W is ΔW and the reference thickness at the time of initialization between the measurement points AB is Ws, the strain amount ε between the measurement points AB is as follows.

  ε = ΔW / Ws

  When the blood pressure difference at this time is ΔP, the elastic modulus Er between the measurement points AB is expressed by the following equation.

  Er = ΔP / ε = ΔP · Ws / ΔW

Therefore, an elastic modulus distribution image can be obtained by measuring the elastic modulus Er with respect to a plurality of points on the tomographic image. As shown in FIG. 8A, when an atheroma has occurred in the blood vessel wall, the elastic modulus is different between the atheroma and the surrounding vascular wall tissue. Therefore, if an elastic modulus distribution image is obtained, it is possible to diagnose the generation and position of atheroma.
Japanese Patent Laid-Open No. 10-5226 JP 2000-229078 A Japanese Patent No. 2507383

  In the method of Patent Document 2, it is important that the SN ratio of the echo signal is large in order to accurately track each measurement point, that is, the amplitude of the echo signal is large and not saturated.

  As a technique for setting the amplitude of a signal to a predetermined value, an automatic gain adjustment circuit (AGC) is known. However, the automatic gain adjustment circuit targets a continuous signal such as a television video signal. For this reason, when a known automatic gain adjustment circuit is used in the ultrasonic diagnostic apparatus disclosed in Patent Document 2, reception is performed at the boundary from a weak echo portion such as a blood vessel lumen to a strong echo portion such as a blood vessel wall. The signal is saturated.

  In order to solve such a problem, Patent Document 3 discloses a case where, in an ultrasonic flaw detection receiver, only an echo from an object is detected using a time gate circuit and the echo signal exceeds a preset threshold value. , Detecting a peak immediately after that and adjusting the gain so that the peak has the maximum amplitude.

  However, when the method of Patent Document 3 is applied to the ultrasonic diagnostic apparatus disclosed in Patent Document 1 or Patent Document 2, the gain changes during reception of echoes constituting one acoustic line. For this reason, the problem that the position of a measurement point cannot be tracked correctly arises.

  It is an object of the present invention to provide an ultrasonic diagnostic apparatus that can solve such problems and can accurately measure a property characteristic of a subject.

  An ultrasonic diagnostic apparatus of the present invention includes a transmitter that generates a drive signal for driving a probe that transmits ultrasonic waves to a subject, and an echo obtained by reflecting the ultrasonic waves on the subject. A receiver that amplifies the received echo signal received by the probe and that can change a gain for amplifying the received echo signal, and stores a maximum value of the received echo signal And an adjustment that adjusts at least one of the gain of the reception unit or the drive signal generated by the transmission unit in synchronization with the deformation cycle of the subject based on the maximum value stored in the storage unit A part.

  In a preferred embodiment, the adjustment unit keeps the drive signal or the gain constant during a period within the deformation cycle of the subject.

  In a preferred embodiment, the adjustment unit adjusts the drive signal or the gain based on the maximum value so that the maximum value of the amplified received echo signal becomes a predetermined value.

  In a preferred embodiment, the adjustment unit adjusts the drive signal or the gain based on the maximum value so that the maximum value of the amplified received echo signal becomes a value within a predetermined range.

  In a preferred embodiment, the adjusting unit adjusts the gain of the receiving unit.

  In a preferred embodiment, the adjustment unit adjusts at least one of an amplitude value, a waveform, and a wave number of the drive signal.

  In a preferred embodiment, the adjusting unit adjusts the driving signal or the gain of the receiving unit in accordance with the cardiac cycle of the subject.

  In a preferred embodiment, the adjusting unit receives biological information from an electrocardiograph or a heart sound meter connected to the subject.

  In a preferred embodiment, at least a part of the subject is periodically deformed by a vibration device, and the adjustment unit receives information on a deformation cycle from the vibration device.

  In a preferred embodiment, the apparatus further includes a tissue property processing unit that receives the reception beam signal from the reception unit and calculates a property characteristic of the subject by a phase difference tracking method.

  In a preferred embodiment, the property characteristic is elastic modulus.

The method for controlling an ultrasonic diagnostic apparatus of the present invention is obtained by applying a drive signal to a probe to transmit ultrasonic waves toward the subject, and reflecting the ultrasonic waves at the subject. Receiving an echo generated by the probe to obtain a received echo signal;
A step of storing a maximum value of the received echo signal; a step of amplifying the received echo signal; and a gain of the amplification step in synchronization with a period of deformation of the subject based on the stored maximum value or Adjusting at least one of the drive signals in the transmitting step.

  In a preferred embodiment, the adjusting step keeps the drive signal or the gain constant during a period within the deformation cycle of the subject.

  In a preferred embodiment, the adjusting step adjusts the drive signal or the gain based on the maximum value so that the maximum value of the amplified received echo signal becomes a predetermined value or a value within a predetermined range. To do.

  In a preferred embodiment, the adjusting step adjusts a gain of the receiving unit.

  In a preferred embodiment, the adjusting step adjusts at least one of an amplitude value, a waveform, and a wave number of the drive signal.

  In a preferred embodiment, the adjusting step adjusts the driving signal or the gain of the receiving unit in accordance with the cardiac cycle of the subject.

  In a preferred embodiment, the adjusting step receives biological information from an electrocardiograph or a heart sound meter connected to the subject, and adjusts the drive signal or the gain of the receiving unit based on the biological information.

  In a preferred embodiment, at least a part of the subject is periodically deformed by a vibration device, and the adjustment step receives information on a deformation cycle from the vibration device.

  According to the ultrasonic diagnostic apparatus of the present invention, since the gain in the receiving unit is adjusted in synchronization with the deformation cycle of the subject, the S / N ratio of the received echo signal or the received beam signal is improved and accurate. Measurement can be performed. Further, since the gain is maintained at a constant value during a period synchronized with the deformation cycle of the subject, the measurement conditions are constant within the deformation cycle. For this reason, it becomes possible to measure a property characteristic, especially an elastic characteristic with high precision.

  First, the influence caused by saturation of the received signal in the ultrasonic diagnostic apparatus will be described. FIG. 1 is a graph showing the relationship between the saturation of the received signal and the tracking error when tracking the position of the measurement point of the subject by simulation. The saturation of the received signal is obtained based on the following equation.

  (Saturation) = (Maximum value of received signal amplitude) / (Maximum value in signal processing circuit)

  Here, the maximum value of the amplitude of the received signal is the maximum amplitude of the received signal after being amplified in the receiving unit, and the maximum value in the signal processing circuit is the maximum value of the received signal that can be processed in the ultrasonic diagnostic apparatus. . As shown in FIG. 1, when the degree of saturation exceeds 100%, the tracking SN ratio decreases.

  FIG. 2 is a graph in which the relationship between the saturation of the received signal and the relative elastic modulus is obtained by simulation. The degree of saturation is changed by changing the amplification factor of the signal obtained by a certain measurement. The relative elastic modulus is based on the elastic modulus when the degree of saturation is 100%. Since the same measurement data is used, the elastic modulus should not change regardless of the amplification factor of the signal. However, as shown in FIG. 2, the elastic modulus decreases as the saturation level of the received signal increases.

  From these results, it can be seen that the measurement error increases as the reception signal becomes saturated, and that the amplitude of the reception signal needs to be adjusted so that the reception signal is not saturated in order to perform highly accurate measurement. . Further, when the elastic modulus of the subject is obtained by the ultrasonic diagnostic apparatus, it is preferable to make the measurement conditions constant during a period in which a strain amount of the subject and a stress difference that causes the strain are applied. This is because if the measurement conditions change in the middle, the correct elastic modulus may not be measured.

  Considering these points, the ultrasonic diagnostic apparatus of the present invention is based on the maximum value of the received signal received using the probe, or the drive signal generated by the transmitter in synchronization with the deformation cycle of the subject or The gain of the receiving unit is adjusted. Hereinafter, embodiments of the ultrasonic diagnostic apparatus of the present invention will be described with reference to the drawings.

  FIG. 3 shows a block diagram of the ultrasonic diagnostic apparatus 200. The ultrasonic diagnostic apparatus 200 measures the shape characteristic or the characteristic characteristic of the subject using the probe 101. In particular, when the subject is a living body, it is suitably used for measuring the elastic modulus of the arterial wall tissue. Here, the shape characteristics are the shape of the subject tissue, or the movement speed of the subject tissue due to the temporal change of the shape, the position displacement amount that is an integrated value thereof, and the thickness change between two points set in the subject tissue. The amount. The property characteristic of the subject refers to the elastic modulus of the subject tissue. Hereinafter, a living body including an artery will be described as an example of a subject. The artery is deformed so that it periodically expands and contracts as the heart ejects blood.

The ultrasonic diagnostic apparatus 200 includes a transmission unit 102, a reception unit 103, a storage unit 110, an adjustment unit 111, and a tissue property processing unit 105. In addition, a control unit 100 is provided to control these units. The transmission unit 102 generates a drive signal for driving the probe 101 that transmits ultrasonic waves to the subject based on the control of the control unit 100. As will be described in detail below, the transmission unit 102 may generate a drive signal by changing at least one of the amplitude, waveform, and wave number of the drive signal to be generated based on a command from the adjustment unit 111. . FIG. 4A schematically shows the drive signal. Driving signals d _1, d ₂ ··· d _n it is transmitted repeatedly at predetermined time intervals. Each drive signal includes a plurality of pulse signals.

The probe 101 includes a plurality of piezoelectric vibrators, and each piezoelectric vibrator vibrates when a drive signal is applied to generate ultrasonic waves. The generated ultrasonic wave is transmitted toward the subject. The ultrasonic wave reflected from the subject returns to the probe 101 as an echo. The probe 101 converts the received echo into an electrical signal and outputs it as a received echo signal to the receiving unit 103. FIG. 4B schematically shows the received echo signal. In response to the drive signals _{d 1, d 2 ··· d n} , the received echo signals r _1, r ₂ ···· r _n can be obtained.

  The receiving unit 103 includes a variable gain amplifier and a beam former. As will be described in detail below, the variable gain amplifier amplifies the received echo signal with a gain based on the control signal from adjustment section 111. The amplified received echo signal is synthesized so as to obtain an ultrasonic beam from a position and direction determined by the beamformer. Thereby, the receiving part 103 outputs a received beam signal. The receiving unit 103 also outputs the received echo signal before being amplified by the variable gain amplifier to the storage unit 110.

As shown in FIG. 4 (c), the storage unit 110 receives the received echo signals _{r 1, r 2 ···· r n} , and stores the maximum value w2 of the received echo signals in a predetermined time period T. After the elapse of a predetermined period, the maximum value w2 is output to the adjustment unit 111, the maximum value is cleared, and the maximum value of the received signal in the next period starts to be stored. The predetermined period is preferably synchronized with the deformation cycle of the subject. When the subject is a living body and deforms in accordance with the cardiac cycle, the storage unit 110 receives a signal synchronized with the cardiac cycle from the synchronous signal detector 109 as shown in FIG. 3, and determines a predetermined period. It is preferable. The synchronization signal detector 109 may be, for example, an electrocardiograph or a heart sound meter that measures a subject. The predetermined period for which the storage unit 110 obtains the maximum value only needs to be synchronized with the deformation cycle of the subject and does not have to match. That is, it may coincide with a period twice as long as the deformation period of the subject.

  Based on the maximum value of the received signal received, adjustment unit 111 determines the gain when the received signal is amplified so that the amplified received echo signal has a predetermined target value or a value within the target range. A control signal is output to the variable gain amplifier of the receiving unit 103 so as to amplify the received echo signal for the next predetermined period with the gain.

  The target value or target range is preferably determined based on the maximum value that can be processed by the tissue property processing unit 105. For example, a value of 95% of the maximum value that can be processed by the tissue property processing unit 105 is set as a target value, or a range of 90% to 95% of the maximum value is set as a target range. As described above, the gain at the time of amplifying the reception echo signal in the reception unit 103 is determined based on the maximum value of the reception echo signal acquired in the immediately preceding period. For this reason, the determined gain may not be optimal during that period. However, in two adjacent periods, there is usually no significant change between two received echo signals received, and the maximum values in the two adjacent periods are considered to be approximately equal. For this reason, even if the received echo signal is amplified with the determined gain by setting the target value or the target range in consideration of the range of the maximum value that can fluctuate in two adjacent periods, it is sufficiently large. In addition, it is possible to obtain a received beam signal having an amplitude that does not saturate.

  When setting the target range, first, using the maximum value of the received echo signal and the currently set gain value, it is checked whether the maximum value of the amplified received echo signal falls within the target range. . If it is within the target range, a control signal is output to the receiving unit 103 so that the same value is used without updating the gain value. Thereby, it is possible to prevent the gain value from fluctuating frequently and perform stable measurement.

  The tissue property processing unit 105 includes, for example, an orthogonal detector, a tissue tracking unit, and a tissue property value calculation unit, and tracks the position of the subject tissue by the phase difference tracking method disclosed in Patent Documents 1 and 2. Specifically, the quadrature detector phase-detects the received beam signal, and the tissue tracking unit obtains the motion speed of each measurement point set in the subject tissue based on the phase difference of the received beam signal. Furthermore, the relative position of each measurement point is obtained by integrating the motion speed. The tissue tracking unit may obtain a thickness change amount (distortion amount) between any two measurement points from the relative position. As shown in FIG. 3, the ultrasonic diagnostic apparatus 200 may receive information on the maximum blood pressure and the minimum blood pressure of the subject from the sphygmomanometer 108 and use them to obtain the elastic modulus of the subject tissue.

  The ultrasonic diagnostic apparatus 200 may further include a tomographic image processing unit 104. The tomographic image processing unit 104 includes a filter, a logarithmic amplifier, a detector, and the like, and converts the received beam signal received from the receiving unit 103 into a signal having luminance information corresponding to the signal intensity. As a result, the tomographic image processing unit 104 generates a tomographic image of the subject on which gradation display by luminance has been performed.

  The image synthesis unit 106 synthesizes the data received from the tomographic image processing unit 104 and the tissue property processing unit 105 and displays them on the monitor 107. Various data obtained by the tissue property processing unit 105 may be displayed as numerical values on the monitor 107, or may be displayed as a graph or a two-dimensional distribution image superimposed on the tomographic image obtained from the tomographic image processing unit 104. Good. The calculation in the tissue property processing unit 105 and the data synthesis in the image synthesis unit 106 may be updated in synchronization with the deformation cycle of the subject.

  Next, the deformation cycle of the subject will be described in detail. FIG. 5A shows the electrocardiographic waveform of the subject, and FIGS. 5B and 5C show the change in the inner diameter of the artery in the subject and the change in the thickness of the artery wall, respectively. FIG. 5D shows the deformation period T of the subject, and FIG. 5E shows the gain of the variable gain amplifier of the receiving unit. As shown in FIGS. 5 (b) and 5 (c), the artery of the subject repeatedly expands and contracts periodically due to the blood flow generated by the heartbeat, and the thickness of the artery wall also changes periodically. is doing. Thus, the subject is deformed periodically. The period of these deformations is synchronized with the heartbeat, and is synchronized with the electrocardiographic waveform shown in FIG.

  The ultrasonic diagnostic apparatus of the present invention is characterized in that the update of the gain value in the receiving unit is synchronized with the deformation cycle of the subject, and the gain value is made constant within the synchronized period. As described above, when the elastic modulus of the arterial wall is obtained, the difference Δw between the maximum value and the minimum value of the thickness change amount is represented by an R wave in the electrocardiogram waveform as shown in FIGS. Occurs immediately after being observed. For this reason, it is preferable to determine the gain value update period in the receiving unit so that the gain value becomes constant during the period in which Δw is observed in the thickness of the artery wall. As is apparent from the figure, when the subject deforms in accordance with the cardiac cycle, it is preferable to use the R wave of the electrocardiographic waveform as a reference for the cycle of updating the gain value. That is, the electrocardiograph is the synchronization signal detector 109, the R wave is used as a trigger, the storage unit 110 measures the maximum value of the received echo signal, and the adjustment unit 111 determines the gain using the R wave as a trigger, It is preferable to output the control signal to the receiving unit 103.

  Thus, according to the ultrasonic diagnostic apparatus of the present invention, the S / N ratio of the received echo signal or the received beam signal is improved because the gain in the receiving unit is adjusted in synchronization with the deformation cycle of the subject. It is possible to perform accurate measurement. Further, since the gain is maintained at a constant value during a period synchronized with the deformation cycle of the subject, the measurement conditions are constant within the deformation cycle. For this reason, it becomes possible to measure a property characteristic, especially an elastic characteristic with high precision.

  In the above embodiment, the subject is actively deformed by the heartbeat, but the ultrasonic diagnostic apparatus of the present invention also has the above-mentioned property characteristics such as the elastic characteristics of the tissue that does not actively deform, such as a stationary organ. It is possible to measure with high accuracy by the method. FIG. 6 schematically shows a configuration for measuring the elastic characteristics of a stationary organ. When the subject 210 includes a stationary organ 212 such as a liver, the vibration device 310 is used to periodically deform the stationary organ 212. The vibration device 310 includes an arm 300 having a contact portion 302 that comes into contact with the subject 210 and a drive unit 304, and the arm 300 vibrates at a predetermined cycle by the drive unit 304 as indicated by an arrow. When the contact portion 302 is brought into contact with the subject and the arm 300 is vibrated, the subject can be periodically deformed.

  When measuring the elastic characteristics of the stationary organ 212, ultrasonic waves are transmitted and received by the probe 101 while periodically pressing and relaxing the stationary organ 212 of the subject 210 using the vibration device 310. At this time, a trigger signal synchronized with the period of vibration is input from the vibration device 310 to the storage unit 110, the adjustment unit 111, the tissue property processing unit 105, and the image composition unit 106, and measurement is performed as described above. Thereby, the thickness change amount (distortion amount) between the measurement points set in the stationary organ 212 can be measured. Further, the pressure difference applied to the subject 210 can be obtained from the vibration of the vibration device 310. Therefore, the elastic modulus can be obtained using the thickness change amount and the pressure difference.

  Thus, when using the vibration apparatus 310, it is also possible to obtain | require the elasticity modulus of the subject which is not a biological body. For example, it is possible to measure the elastic modulus of a pipe made of an elastic body and determine the deterioration state of the pipe.

Further, in the above embodiment, the gain in the receiving unit is synchronized with the cycle of the subject, so that the signal input to the composition property processing unit 105 is not saturated and has sufficient signal strength. It was. However, the amplitude of the received echo signal may be adjusted by modifying the waveform of the drive wave for transmitting the ultrasonic wave to the subject. Specifically, as illustrated in FIG. 4A, the adjustment unit 111 changes the drive signals d _{1 to} d _n generated in the transmission unit 102 based on the maximum value of the received echo signal received from the storage unit 110. . As described above, since the driving signal d ₁ to d _n for transmitting one of the ultrasonic beam includes a plurality of pulse signals, the amplitude w1 and waveform of the pulse signal, by changing the wave number, received echo The amplitude of the signal can be adjusted. The adjustment unit 111 may change the drive signal generated by the transmission unit 102 in addition to the gain in the reception unit.

  Moreover, in the said embodiment, the period which calculated | required the maximum value of the received echo signal and the period which amplifies a received echo signal by the gain determined using the maximum value differed. However, by providing the receiving unit 103 with a memory that temporarily stores at least one period of the received echo signal, it is possible to amplify the received echo signal during the period for which the maximum value has been obtained with the gain obtained from the maximum value. . For example, while obtaining the maximum value of the received echo signal for one cycle, the received echo signal is stored in the memory, the gain is determined based on the maximum value, the received echo signal is read from the memory, and the determined gain is used. To amplify the received echo signal. This makes it possible to amplify the received echo signal so that the received echo signal does not saturate and has a sufficiently large amplitude. In this case, it is preferable to secure a sufficient dynamic range in the memory provided in the receiving unit.

  Furthermore, in the above-described embodiment, the signal obtained from the synchronization signal detector 109 is input to the storage unit 110 and the adjustment unit 111 as a trigger, and the period during which the gain is constant and the period during which the maximum value is measured are updated. However, the signal obtained from the synchronization signal detector 109 may be input only to one of the storage unit 110 and the adjustment unit 111. For example, the signal obtained from the synchronization signal detector 109 is input to the storage unit 110, and the adjustment unit 111 updates the control signal for adjusting the drive signal and gain each time the maximum value output from the storage unit 110 is updated. May be. Further, based on the signal obtained from the synchronization signal detector 109, the adjustment unit 111 updates the control signal for adjusting the drive signal and gain, and measures the maximum value of the storage unit 110 based on the update of the control signal. The period may be updated.

  The present invention is suitably used for an ultrasonic diagnostic apparatus that can accurately measure the shape characteristics or property characteristics of various subjects. In particular, it can be suitably used for an ultrasonic diagnostic apparatus that measures the elastic modulus of an arterial wall of a living body including an artery.

It is the graph which calculated | required the relationship between the saturation of a received signal, and the tracking accuracy of a measurement point by simulation. It is the graph which calculated | required the relationship between the saturation of a received signal, and an elasticity modulus by simulation. 1 is a block diagram showing an embodiment of an ultrasonic diagnostic apparatus according to the present invention. (A) And (b) is a figure which shows typically the waveform of a drive signal and a reception echo signal, (c) is a figure which shows a period. (A)-(e) is a figure which shows the change of the gain set in the electrocardiogram waveform, the inner diameter change of an artery, the thickness change of an arterial wall, the deformation | transformation of an artery, and a receiving part. It is a schematic diagram which shows the structure for calculating | requiring the elasticity modulus of a stationary organ. It is a figure explaining the method of tracking a structure | tissue from the phase difference of an ultrasonic echo signal. (A) And (b) is a figure explaining the method of calculating | requiring a distortion amount from the tracking waveform of a structure | tissue.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Control part 101 Probe 102 Transmission part 103 Reception part 104 Tomographic image process part 105 Tissue property process part 106 Image composition part 107 Monitor 108 Sphygmomanometer 109 Synchronous signal detector 110 Storage part 111 Adjustment part 200 Ultrasound diagnostic apparatus 210 Subject Specimen 212 Stationary organ 300 Arm 302 Contact unit 304 Drive unit 310 Excitation device

Claims (19)

A transmitter that generates a drive signal for driving a probe that transmits ultrasonic waves to the subject;
A receiving unit that receives an echo obtained by reflection of the ultrasonic wave at the subject by the probe and amplifies the obtained reception echo signal, and changes a gain for amplifying the reception echo signal. A receiver that can
A storage unit for storing the maximum value of the received echo signal;
Based on the maximum value stored in the storage unit, an adjustment unit that adjusts at least one of the gain of the reception unit or the drive signal generated by the transmission unit in synchronization with the deformation cycle of the subject;
An ultrasonic diagnostic apparatus comprising:   The ultrasonic diagnostic apparatus according to claim 1, wherein the adjustment unit maintains the drive signal or the gain constant during a period within a deformation cycle of the subject.   The ultrasonic diagnostic apparatus according to claim 2, wherein the adjustment unit adjusts the drive signal or the gain so that a maximum value of the amplified received echo signal becomes a predetermined value based on the maximum value.   The ultrasonic diagnosis according to claim 2, wherein the adjustment unit adjusts the drive signal or the gain so that a maximum value of the amplified received echo signal becomes a value within a predetermined range based on the maximum value. apparatus.   The ultrasonic diagnostic apparatus according to claim 1, wherein the adjustment unit adjusts a gain of the reception unit.   The ultrasonic diagnostic apparatus according to claim 1, wherein the adjustment unit adjusts at least one of an amplitude value, a waveform, and a wave number of the drive signal.   The ultrasonic diagnostic apparatus according to claim 1, wherein the adjustment unit adjusts the drive signal or the gain of the reception unit in accordance with a cardiac cycle of the subject.   The ultrasonic diagnostic apparatus according to claim 7, wherein the adjustment unit receives biological information from an electrocardiograph or a heart sound meter connected to the subject.   The ultrasonic diagnostic apparatus according to claim 1, wherein at least a part of the subject is periodically deformed by a vibration device, and the adjustment unit receives information related to a deformation cycle from the vibration device. The ultrasonic diagnostic apparatus according to claim 9, further comprising a tissue property processing unit that receives the reception beam signal from the reception unit and calculates a property characteristic of the subject by a phase difference tracking method.   The ultrasonic diagnostic apparatus according to claim 10, wherein the property characteristic is an elastic modulus. Transmitting an ultrasonic wave toward the subject by applying a drive signal to the probe; and
Receiving an echo obtained by reflecting the ultrasonic wave at the subject by the probe, and obtaining a received echo signal;
Storing a maximum value of the received echo signal;
Amplifying the received echo signal;
Adjusting at least one of the gain of the amplification step or the drive signal in the transmission step in synchronization with a deformation period of the subject based on the stored maximum value;
A method for controlling an ultrasonic diagnostic apparatus including:   The method of controlling an ultrasonic diagnostic apparatus according to claim 12, wherein the adjusting step keeps the drive signal or the gain constant during a period within a deformation cycle of the subject.   The adjustment step adjusts the drive signal or the gain based on the maximum value so that the maximum value of the amplified received echo signal becomes a predetermined value or a value within a predetermined range. Method for ultrasonic diagnostic apparatus.   The method of controlling an ultrasonic diagnostic apparatus according to claim 12, wherein the adjusting step adjusts a gain of the receiving unit.   The method of controlling an ultrasonic diagnostic apparatus according to claim 12, wherein the adjusting step adjusts at least one of an amplitude value, a waveform, and a wave number of the drive signal.   15. The method of controlling an ultrasonic diagnostic apparatus according to claim 12, wherein the adjusting step adjusts the drive signal or the gain of the receiving unit in accordance with a cardiac cycle of the subject.   The ultrasonic wave according to claim 17, wherein the adjusting step receives biological information from an electrocardiograph or a heart sound meter connected to the subject, and adjusts the gain of the driving signal or the receiving unit based on the biological information. Diagnostic device control method.   18. The method of controlling an ultrasonic diagnostic apparatus according to claim 17, wherein at least a part of the subject is periodically deformed by a vibration device, and the adjustment step receives information related to a deformation cycle from the vibration device.

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