JP2010268945A - Ultrasonograph - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ultrasonograph which is configured to improve display images in real time, and clear tomograms from shallow portions to deep portions to be obtained by a simple structure. <P>SOLUTION: The ultrasonograph has wave transmission means to transmit ultrasonic waves to different depth positions at least once during a frame period at time intervals shorter than the time from the transmission of ultrasonic waves to the reception of higher harmonics caused in the deepest position of the interior of a subject, when a focal point is set at the deepest position. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an ultrasonic diagnostic apparatus.

  An ultrasonic diagnostic apparatus is a medical imaging device that obtains a tomographic image of soft tissue in a living body in a minimally invasive manner from the body surface by an ultrasonic pulse reflection method. Compared to other medical imaging equipment, this ultrasound diagnostic device has features such as being smaller and cheaper, without exposure to X-rays, etc., being highly safe, and capable of blood flow imaging by applying the Doppler effect. Yes. Therefore, it is widely used in the circulatory system (coronary artery of the heart), digestive system (gastrointestinal), internal medicine system (liver, pancreas, spleen), urology system (kidney, bladder), and obstetrics and gynecology.

  Conventionally, such an ultrasonic diagnostic apparatus is called a harmonic imaging (HI) method in which a harmonic component generated by nonlinear propagation of ultrasonic waves is taken out, and an ultrasonic image is generated and displayed based on the harmonic component. Have been used.

  The harmonic imaging is a technique for detecting and imaging a harmonic component contained in an ultrasonic reception signal (for example, transmitting a 2 MHz ultrasonic wave and imaging with a 4 MHz harmonic wave), and is composed of microbubbles. It was developed for the purpose of more efficiently detecting ultrasound contrast agents.

  The microbubbles have strong nonlinear scattering characteristics, and the scattered signal contains a higher harmonic component than that of the living tissue. Therefore, by detecting only this harmonic component, it is possible to visualize a minute blood flow (perfusion) that is normally buried in an echo from the surrounding tissue (fundamental wave).

  In recent years, tissue harmonic imaging (THI) has attracted attention. This is focused on the image quality improvement effect of the harmonic imaging method, and is characterized in that any patient can obtain a high-contrast B-mode image with reduced noise, and is excellent in rendering the endocardium and the like. In the tissue harmonic imaging method, harmonics generated by so-called non-linearity of propagation in which a transmitted ultrasonic wave “propagates” while being distorted in a living body are visualized.

  Since the amplitude of this harmonic is proportional to the propagation distance of the ultrasonic wave and the square of the sound pressure of the fundamental wave, it is concentrated on the central axis of the ultrasonic beam (region with high sound pressure). That is, it is possible to form a sharp ultrasonic beam having a narrow main lobe and a low side lobe level as compared with the case where the fundamental wave is used.

  In this way, in the tissue harmonic imaging method, a beam having a narrow beam width and a low side lobe level can be formed. Therefore, the azimuth resolution is improved by reducing the beam width, and the contrast resolution is improved by reducing the side lobe level.

  Conventionally, in such an ultrasonic diagnostic apparatus, beam-like ultrasonic waves each having a focus set at a plurality of different depth positions in the same beam direction are transmitted, and based on the reflected waves of the transmitted ultrasonic waves. A multistage focus method for displaying in-vivo information has been used (see, for example, Patent Document 1).

  In the multi-stage focusing method, for example, the focal points F1, F2, and F3 for converging the ultrasonic beam are different from each other according to the depth, such as F1 is a short distance, F2 is a medium distance, and F3 is a long distance. And the reflected waves of the transmitted ultrasonic waves are spliced according to the respective focal points F1, F2, and F3 to obtain one scanning line data.

  By changing the focal distance at which the ultrasonic beam converges in accordance with the depth of the living body in this way, the divergence of the ultrasonic beam is suppressed, resulting in resolution over the entire region from a short distance to a long distance in the living body. It is possible to obtain a good image.

  However, when the conventional multistage focus method is used, if n focal points are set, it is necessary to perform transmission and reception n times in order to obtain one scanning line data. Becomes approximately 1 / n. For this reason, as the number of focal points n is increased in order to increase the resolution, the real-time property of image display is lost, and a necessary tomographic image cannot be obtained for a fast-moving organ.

  In order to solve such a problem, a drive signal obtained by synthesizing a drive signal having a drive voltage and a drive frequency different from each other according to each focus by delaying by a time corresponding to each focus is applied to a predetermined piezoelectric element. An ultrasonic diagnostic apparatus to be applied has been proposed (see, for example, Patent Document 2). The ultrasonic diagnostic apparatus disclosed in Patent Document 2 sorts reflected wave signals according to the frequency at the time of reception, and delays the selected reflected wave signals by the same delay time as in the case of transmission. It is configured to amplify and obtain an image with good resolution over the entire area.

Japanese Utility Model Publication No. 2-88610 JP-A-6-1114056

  When using the tissue harmonic imaging method, harmonics are generated only in the region near the focal position where the wave is transmitted in the direction of the sound ray, so the ultrasound beam converges to obtain a good image from shallow to deep. It is necessary to set a large number of focal points n. Therefore, when the display area is expanded, there is a problem that the frame rate is reduced, the real-time property is lost, and a necessary tomographic image cannot be obtained for a fast-moving organ.

  On the other hand, in the method disclosed in Patent Document 2, the piezoelectric element is driven by a drive signal synthesized by delaying ultrasonic waves having different frequencies by a time corresponding to each focal point. The delay time or the like of the signal is likely to vary depending on the mounting conditions and the bandwidth of the piezoelectric element that is a load. Therefore, a complicated circuit is required, and even if such a circuit is used, the intended wave transmission cannot be performed, and a good result may not be obtained.

  Moreover, since it is necessary to select (filter) a large number of frequencies in the received signal processing, there is a problem that the signal processing becomes complicated and the ultrasonic diagnostic apparatus becomes expensive.

  The present invention has been made in view of the above-described problems, and it is possible to improve the real-time property of image display with a simple configuration and to obtain a clear tomographic image from a shallow part to a deep part. An object is to provide an ultrasonic diagnostic apparatus.

  In order to solve the above problems, the present invention has the following characteristics.

1. A drive signal is applied to an ultrasonic probe in which a plurality of piezoelectric elements are arranged, and beam-like ultrasonic waves set in focus at a plurality of different depth positions in the same beam direction are applied to the subject at a predetermined frame period. It is configured to sequentially transmit the wave inside and receive the harmonic components generated from the vicinity of the depth position where the focus is set by the beam-like ultrasonic wave, and visualize the inside of the subject. An ultrasound diagnostic apparatus,
When the focal point is set at the deepest position, the ultrasonic wave is transmitted at a time interval shorter than the time from when the harmonic wave generated at the deepest position inside the subject is received, An ultrasonic diagnostic apparatus comprising: a wave transmitting means for transmitting the ultrasonic wave at a depth position different from the previous time at least once during a frame period.

2. The harmonics are
2. The ultrasonic diagnostic apparatus according to 1 above, wherein the ultrasonic diagnostic apparatus is a third harmonic that is three times the fundamental frequency of the drive signal.

3. The wave transmitting means is
The focus is set at a predetermined depth position, the ultrasonic wave is transmitted, and after the period for receiving the harmonics generated at the predetermined depth position has elapsed, the focus is set at different depth positions sequentially. The ultrasonic diagnostic apparatus according to 1 or 2, wherein the ultrasonic wave is transmitted.

4). The wave transmitting means is
After setting the focus at a predetermined depth position and transmitting the ultrasonic wave, before receiving the harmonics generated at the predetermined depth position,
The focus is set at different depth positions so that the period of receiving the harmonics generated by transmitting ultrasonic waves does not overlap the period of receiving the harmonics generated at the predetermined depth position. 3. The ultrasonic diagnostic apparatus according to 1 or 2 that transmits ultrasonic waves.

  According to the present invention, at least once during the frame period in which multi-stage focusing is performed, the focus is set at the deepest position and ultrasonic waves are transmitted, and then the harmonics reflected from the deepest position in the living body are reflected. Ultrasonic waves are transmitted to different depth positions at a time interval shorter than the time until reception.

  Therefore, it is possible to provide an ultrasonic diagnostic apparatus that can improve the real-time property of image display with a simple configuration and obtain a clear tomographic image from a shallow part to a deep part.

It is a figure which shows the external appearance structure of the ultrasound diagnosing device in embodiment. It is a block diagram which shows the electrical structure of the ultrasonic diagnosing device in embodiment. It is a figure which shows each focus area | region set by the multistage focus method. It is a figure which illustrates typically until an ultrasonic wave is transmitted to the focus of each focus area | region, and is received. It is a time chart explaining a transmission timing.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. However, the present invention is not limited to the embodiment. In addition, the structure which attached | subjected the same code | symbol in each figure shows that it is the same structure, The description is abbreviate | omitted.

  FIG. 1 is a diagram illustrating an external configuration of an ultrasonic diagnostic apparatus according to an embodiment.

  The ultrasonic diagnostic apparatus 100 transmits ultrasonic waves (ultrasound signals) to a subject such as a living body (not shown) and reflects the reflected ultrasonic waves (echoes, ultrasonic signals) reflected by the received subject. The internal state in the subject is imaged as an ultrasound image and displayed on the monitor 10.

  The ultrasonic probe 2 transmits an ultrasonic wave (ultrasonic signal) to the subject and receives a reflected wave of the ultrasonic wave reflected by the subject. As shown in FIG. 1, the ultrasonic probe 2 is connected to an ultrasonic diagnostic apparatus main body 14 via a cable 15.

  The input unit 13 includes a switch, a keyboard, and the like. The input unit 13 inputs a command for instructing the user to start diagnosis, selects a fundamental wave mode or a non-fundamental wave mode, which will be described later, and inputs data such as personal information of a subject. Is provided to do.

  The monitor 10 is composed of a liquid crystal panel or the like, and displays an imaged ultrasonic image.

  FIG. 2 is a block diagram showing an electrical configuration of the ultrasonic diagnostic apparatus according to the present embodiment.

  First, the overall configuration will be described with reference to FIG.

  A plurality of piezoelectric elements 8 for mutual conversion between electrical signals and acoustic signals are arranged at the distal end portion of the ultrasound probe 2 (not shown in FIG. 2). In the following description, it is assumed that one piezoelectric element constitutes one channel. A transmission processing unit 1 is connected to the ultrasonic probe 2.

The transmission processing unit 1 is a drive subjected to delay processing so as to form an ultrasonic wave in a beam shape at a timing corresponding to the mode set by the control unit 99 and to converge at an arbitrary depth to form a focal point. A signal is applied to each channel of the ultrasonic probe 2. Thereby, the piezoelectric element of each channel vibrates and generates an ultrasonic wave. Note that the frequency spectrum of this ultrasonic wave is usually slightly dispersed around the frequency of the drive signal (fundamental frequency f ₀ ). The transmission processing unit 1 is a wave transmitting means of the present invention.

The ultrasonic wave generated by the ultrasonic probe 2 is transmitted to the subject, propagates inside the subject, is reflected by a discontinuous surface of the acoustic impedance in the middle thereof, and is echoed to the ultrasonic probe 2 as an echo. Come back. This echo, in addition to the fundamental wave component of the fundamental frequency f _0, ultrasonic wave "propagates" while distortion inside of the subject (living body), non-fundamental other than the fundamental frequency f ₀ by the nonlinearity of the so-called propagation Ingredients are generated. Among the non-fundamental component, it can be utilized twice the second harmonic component of the fundamental frequency f _0, and three times the third harmonic component in the image formation for diagnosis.

  The echo returned to the ultrasonic probe 2 is weakened by mechanically vibrating the piezoelectric elements 8 (not shown in FIG. 2) arranged in the ultrasonic probe 2, contrary to the time of transmission. Generate electrical signals. This signal is taken into the received signal processing unit 3, amplified by a preamplifier, and added through the same delay processing as that during transmission.

This received signal has a fundamental wave whose pass band is set to a predetermined band centered on the fundamental frequency f ₀ in order to mainly extract the fundamental wave component from the received signal in the fundamental wave mode (normal imaging method). The signal is sent to the B-mode processing unit 6 through the band-pass filter (BPF) 4 for use.

In the non-fundamental wave mode (tissue harmonic imaging method), the pass band is set to a predetermined band centered on a frequency twice or three times the fundamental frequency f ₀ in order to extract harmonic components from the received signal. It is sent to a B-mode processing unit 6 through a harmonic bandpass filter (BPF) 5.

  The B-mode processing unit 6 generates a normal B-mode image based on the fundamental wave component from the fundamental wave band-pass filter 4 in the fundamental wave mode, and the harmonic band-pass filter 5 in the non-fundamental wave mode. A tissue harmonic image is generated based on the harmonic components from the. These images are reconstructed by a digital scan converter (DSC) 9, converted into a video signal, and displayed on the monitor 10.

  The control unit 99 includes a CPU 98 (central processing unit), a storage unit 96, and the like, reads a program stored in the storage unit 96 into the RAM 97, and controls each unit of the ultrasound diagnostic apparatus 100 according to the program. The storage unit 96 includes a RAM (Random Access Memory), a ROM (Read Only Memory), and the like.

  The control unit 99 sets a mode (fundamental wave mode or non-fundamental wave mode) input from the input unit 13 by the operator in the transmission processing unit 1 and the reception processing unit 3.

  In the present embodiment, an example in which the fundamental wave mode and the non-fundamental wave mode are switched when the operator performs a mode switching operation with the input unit 13 will be described. However, for example, every time one section is scanned once. Alternatively, it may be switched automatically every time transmission / reception is performed once.

  Next, the multistage focusing method performed in this embodiment will be described with reference to FIGS. 3, 4, and 5.

  FIG. 3 is a diagram illustrating each focus region set by the multistage focus method, and FIG. 4 is a diagram schematically illustrating the process from transmission of ultrasonic waves to the focus of each focus region until reception. FIG. 5 is a time chart for explaining the transmission timing of this embodiment.

  In the present embodiment, a case will be described in which images of four focus areas E1, E2, E3, and E4 that are equally spaced in the depth direction of the living body (subject) shown in FIG. 3 are obtained.

  As shown in FIG. 4A, in the ultrasonic probe 2, a plurality of piezoelectric elements 8 for mutual conversion between electrical signals and acoustic signals are arranged in an array. The transmission processing unit 1 forms ultrasonic waves in the form of a beam, and sequentially applies drive signals that have been subjected to delay processing so as to form focal points in the focus areas E1, E2, E3, and E4 to the piezoelectric elements 8. The focus of the focus area E1 is F1, the focus of the focus area E2 is F2, the focus of the focus area E3 is F3, and the focus of the focus area E4 is F4. In the example of FIG. Form a focal point on the axis. The ultrasonic beam transmitted from the piezoelectric element 8 is spread again after converging at the position of each focal point as shown in FIG.

  4 (b) to 4 (e) show a period from when an ultrasonic wave is transmitted to each focal point in the non-fundamental wave mode (tissue harmonic imaging method) until a harmonic generated near the focal point is received. The maximum time is schematically shown. Harmonics are generated only in the focus area near the focal position. Since the generated harmonics have a higher attenuation factor than the fundamental wave, they do not travel and reflect deeper areas. Therefore, the maximum time is the time until the fundamental wave of the transmitted ultrasonic wave travels to the deeper boundary of each focus region, and the harmonic generated at the boundary returns to the ultrasonic probe 2.

  FIG. 4E shows a case where the wave is transmitted to the deepest focal point F4, where t is the maximum time until a harmonic generated near the deeper boundary of the focus region E4 is received. FIG. 4D shows a case where waves are transmitted to the focal point F3. When the focus areas are equally spaced, the maximum time required to receive harmonics generated near the deeper boundary of the focus area E3 is 3 /. 4t.

  Similarly, FIG. 4C shows a case where the wave is transmitted to the focal point F2, and FIG. 4B shows a case where the wave is transmitted to the focal point F1, and the harmonics generated near the deeper boundary of the focus region E2, respectively. Is 2/4 × t, and the maximum time until a harmonic generated near the deeper boundary of the focus area E1 is 1/4 × t.

  FIG. 5A is a time chart for explaining the transmission timing of the first embodiment, FIG. 5B is a time chart for explaining the transmission timing of the second embodiment, and FIG. It is a time chart explaining the transmission timing at the time of fundamental wave mode. The horizontal axis in FIG. 5 is a time axis, and shows timing pulses generated by the transmission processing unit 1. At the rise of the timing pulse, an ultrasonic wave transmits a drive signal to the piezoelectric element 8, and an ultrasonic wave is transmitted.

  The transmission processing unit 1 sequentially applies drive signals to the piezoelectric element 8 at the transmission timing of FIG. 5A or the transmission timing of FIG. 5B in the non-fundamental wave mode, and in the fundamental wave mode. A drive signal is sequentially applied to the piezoelectric element 8 at the transmission timing shown in FIG.

  Initially, the transmission timing of 1st Embodiment of Fig.5 (a) is demonstrated.

  In the figure, the ultrasonic beam is transmitted so as to converge at the focal point F1 at the rising edge of the timing pulse indicated by F1. Next, the ultrasonic beam is transmitted so as to converge to the focal point F2 at the rising edge of the timing pulse indicated by F2.

  The time difference between the rising edge of the timing pulse indicated by F1 and the rising edge of the timing pulse indicated by F2 is 1/4 × t, and after transmitting the ultrasonic wave when the focus is set at the deepest position, The time interval is shorter than the time t until the harmonic generated at the deepest position in the subject is received. As described with reference to FIG. 4, the maximum time until the harmonics generated near the deeper boundary of the focus area E1 are received is ¼ × t. Therefore, it occurred in the focus area E1 within the period indicated by E1 in the figure. All harmonics can be received.

  Next, the time difference between the rising edge of the timing pulse indicated by F2 and the rising edge of the timing pulse indicated by F3 is 2/4 × t. As described with reference to FIG. 4, the maximum time required to receive the harmonics generated in the vicinity of the deeper boundary of the focus area E2 is 2/4 × t. Therefore, 1/4 × t to 2/4 indicated by E2 in the figure. All the harmonics generated in the focus area E2 within the period of xt can be received.

  Next, the time difference between the rising edge of the timing pulse indicated by F3 and the rising edge of the timing pulse indicated by F4 is 3/4 × t. Similarly, since the maximum time until the harmonic generated near the deeper boundary of the focus area E3 is received is 3/4 × t, it is within the period of 2/4 × t to 3/4 × t indicated by E3 in the figure. All the harmonics generated in the focus area E3 can be received.

  Next, the time difference between the rising edge of the timing pulse indicated by F4 and the rising edge of the timing pulse indicated by F1 is t. Similarly, since the maximum time until receiving the harmonic generated near the deeper boundary of the focus area E4 is t, the harmonic generated in the focus area E4 within a period of 3/4 × t to t indicated by E4 in the figure. You can receive all the waves.

  Signals received by the piezoelectric element 8 during the periods E1, E2, E3, and E4 are added by the reception processing unit 3 through the same delay processing as that during transmission, pass through the bandpass filter for harmonics 5, and generate harmonics. Only the components are sent to the B-mode processing unit 6 to generate a tissue harmonic image.

  As described above, at the transmission timing of the first embodiment, a period in which a focus is set at a predetermined depth position and an ultrasonic wave is transmitted and a harmonic generated at the predetermined depth position is received has elapsed. After that, ultrasonic waves are transmitted with the focus set at different depth positions. A frame period T1 from the rising edge of F1 to the next rising edge of F1 is one period in which multistage focusing is performed. During this period, ultrasonic beams are sequentially transmitted to the respective focal points. The frame period T1 is 1/4 × t + 2/4 × t + 3/4 × t + t = 10/4 × t.

  Next, the transmission timing in the fundamental wave mode of FIG.

  The fundamental wave travels while diffusing even after the focal position, and reaches the farthest focus area and reflects. Therefore, even when an ultrasonic wave is transmitted so as to converge to the closest focus F1, the fundamental wave travels while diffusing even after passing through the focus area E1, and is reflected at the deeper boundary of the farthest focus area E4. The reflected wave returns even after the period for receiving the reflected wave from the focus area E1 indicated by E1 in FIG. Since the next transmission cannot be performed while the reflected wave returns, it is necessary to wait for the next transmission for the same t as when the ultrasonic wave is transmitted so as to converge to the focal point F4.

  Similarly, when an ultrasonic wave is transmitted so as to converge at the focal point F2 or F3, it is necessary to wait for t until the next wave is transmitted. Therefore, in the fundamental wave mode, the intervals at the rising edge of the timing pulses indicated by F1 to F4 in the figure are all t.

  The signals received by the piezoelectric element 8 during the periods E1, E2, E3, and E4 are added by the reception processing unit 3 through the same delay processing as that during transmission, pass through the fundamental bandpass filter 4, and pass through the fundamental wave. Only the components are sent to the B-mode processing unit 6 to generate a B-mode image.

  A frame period T3 from the rising edge of F1 to the next rising edge of F1 is one period in which multistage focusing is performed. During this period, ultrasonic beams are sequentially transmitted to the respective focal points. The frame period T3 in the fundamental wave mode is 4t.

  As described above, the frame period T1 of the transmission timing of the first embodiment used in the non-fundamental mode is 10/4 × t, which is 37.5% shorter than 4t of the period T3 of the fundamental wave mode. Has been. Therefore, since the frame rate is 1.6 times, the real-time property of the image display is improved, and a clear tomographic image can be obtained from the shallow part to the deep part by the tissue harmonic imaging method using harmonics.

  Next, the transmission timing of the second embodiment in FIG. 5B will be described.

  In the figure, after the ultrasonic beam is transmitted so as to converge at the focal point F4 at the rising edge of the timing pulse indicated by F4, the ultrasonic beam is transmitted so as to converge at the focal point F2 at the rising edge of the timing pulse indicated by F2. The

  The next wave is transmitted at the rise of the timing pulse indicated by F3, and the time difference from the rise of the timing pulse indicated by F4 is t. The period for receiving the harmonics in the focus area E2 is between 1/4 × t + Δt and 2/4 × t + Δt from the rise of the timing pulse indicated by F4, and the period for receiving the harmonics in the focus area E4 is 3 / 4 between t and t. If Δt <¼ × t, the period for receiving the harmonics in the focus area E2 and the period for receiving the harmonics in the focus area E4 do not overlap. The generated harmonics and the harmonics generated in the focus region E4 during the period indicated by E4 in the figure can be received.

  Next, after the ultrasonic beam is transmitted so as to converge at the focal point F3 at the rising edge of the timing pulse indicated by F3, the ultrasonic beam is transmitted so as to converge at the focal point F1 at the rising edge of the timing pulse indicated by F1. Is done.

  The next transmission is at the rise of the timing pulse indicated by F4, and the time difference from the rise of the timing pulse indicated by F3 is 3/4 × t. The period for receiving the harmonic in the focus area E1 is between Δt and ¼ × t + Δt, and the period for receiving the harmonic in the focus area E3 is between 2/4 × t and 3/4 × t. is there. If Δt <1/4 × t, the period in which the harmonics in the focus area E1 are received does not overlap with the period in which the harmonics in the focus area E3 are received, and thus occurs in the focus area E1 during the period E1 in the figure. And the harmonics generated in the focus area E3 during the period indicated by E3 in the figure can be received.

  Signals received by the piezoelectric element 8 during the periods E1, E2, E3, and E4 are added by the reception processing unit 3 through the same delay processing as that during transmission, pass through the bandpass filter for harmonics 5, and generate harmonics. Only the components are sent to the B-mode processing unit 6 to generate a tissue harmonic image.

  As described above, at the transmission timing of the second embodiment, after the ultrasonic wave is transmitted with the focus set at a predetermined depth position, the ultrasonic wave is generated before receiving the harmonics generated at the predetermined depth position. The period for receiving harmonics generated by transmitting sound waves is set at a different depth position that does not overlap with the period for receiving harmonics generated at a predetermined depth position. ing. A frame period T3 from the rising edge of F4 to the next rising edge of F4 is one period in which multistage focusing is performed. During this period, ultrasonic beams are sequentially transmitted to the respective focal points. The frame period T3 is t + 3/4 × t = 7/4 × t, which is shortened by 56.3% as compared with 4t of the period T3 of the fundamental wave mode. Further, it is shortened by 30% compared to the transmission timing of the first embodiment.

  Since the frame rate is about 2.3 times that of the fundamental wave mode, the real-time display of the image is further improved, and a clear tomographic image can be obtained from shallow to deep by a tissue harmonic imaging method using harmonics.

  In particular, when the present invention is applied to the case where the third harmonic is used in the non-fundamental wave mode, the third harmonic is concentrated in the vicinity of the focal position where the sound pressure is high. An image is obtained, and by combining these images, a clearer tomographic image can be obtained from the shallow part to the deep part.

  As described above, according to the present invention, an ultrasonic diagnostic apparatus capable of improving the real-time property of image display with a simple configuration and obtaining a clear tomographic image from a shallow part to a deep part is provided. can do.

DESCRIPTION OF SYMBOLS 1 Transmission processing part 2 Ultrasonic probe 3 Reception processing part 4 Bandpass filter for fundamental waves 5 Bandpass filter for harmonics 6 B mode processing part 8 Piezoelectric element 9 Digital scan converter 10 Display part 13 Input part 14 Super Sound diagnostic apparatus main body 15 Cable 96 Storage unit 98 CPU
99 Control unit 100 Ultrasonic diagnostic apparatus

Claims (4)

A drive signal is applied to an ultrasonic probe in which a plurality of piezoelectric elements are arranged, and beam-like ultrasonic waves set in focus at a plurality of different depth positions in the same beam direction are applied to the subject at a predetermined frame period. It is configured to sequentially transmit the wave inside and receive the harmonic components generated from the vicinity of the depth position where the focus is set by the beam-like ultrasonic wave, and visualize the inside of the subject. An ultrasound diagnostic apparatus,
When the focal point is set at the deepest position, the ultrasonic wave is transmitted at a time interval shorter than the time from when the harmonic wave generated at the deepest position inside the subject is received, An ultrasonic diagnostic apparatus comprising: a wave transmitting means for transmitting the ultrasonic wave at a depth position different from the previous time at least once during a frame period. The harmonics are
The ultrasonic diagnostic apparatus according to claim 1, wherein the ultrasonic diagnostic apparatus is a third harmonic that is three times the fundamental frequency of the drive signal. The wave transmitting means is
The focus is set at a predetermined depth position, the ultrasonic wave is transmitted, and after the period for receiving the harmonics generated at the predetermined depth position has elapsed, the focus is set at different depth positions sequentially. The ultrasonic diagnostic apparatus according to claim 1, wherein the ultrasonic wave is transmitted. The wave transmitting means is
After setting the focus at a predetermined depth position and transmitting the ultrasonic wave, before receiving the harmonics generated at the predetermined depth position,
The focus is set at different depth positions so that the period of receiving the harmonics generated by transmitting ultrasonic waves does not overlap the period of receiving the harmonics generated at the predetermined depth position. The ultrasonic diagnostic apparatus according to claim 1, wherein an ultrasonic wave is transmitted.

Images