JP2004113818A - Ultrasonic imaging device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ultrasonic imaging device which takes a non-linear ultrasonic image efficiently by a second harmonic. <P>SOLUTION: In the ultrasonic imaging device which emits ultrasonic sounds to a subject and utilizes the second harmonic component of an echo, the first phase ultrasonic sounds and the second phase ultrasonic sounds which are substantially different from the first phase by 180° are emitted to the subject alternatively. An echo based on the ultrasonic sounds emitted at the first phase and an echo based on the ultrasonic sounds emitted at the second phase are received. A sum signal of an echo receiver signal based on the ultrasonic sounds emitted at the first phase and an echo receiver signal based on the ultrasonic sounds emitted at the second phase is obtained. <P>COPYRIGHT: (C)2004,JPO

Description

The present invention relates to an ultrasonic imaging method and apparatus, an ultrasonic probe, and an ultrasonic contrast agent. More specifically, the present invention relates to an ultrasonic imaging method and apparatus for an echo source having a non-linear ultrasonic reflection characteristic, an ultrasonic probe, and an ultrasonic contrast agent.

In recent years, the second harmonic imaging method using the resonant nonlinear response of microbubbles to ultrasonic waves is being studied. In addition, a contrast agent containing soluble microballoons as a main component has been developed.

The second harmonic imaging method utilizes the fact that a microbubble contained in a contrast agent generates an echo including the second harmonic of the irradiated ultrasonic wave due to its resonant nonlinear response. This echo is about 100 times more sensitive than the Doppler signal. An image of the contrast medium injection site is formed based on the received second harmonic echo, and the function of the tissue of interest is measured based on a temporal change in the concentration of the contrast medium.

(1) In an ultrasonic imaging apparatus, since a focused wavefront of an ultrasonic wave is transmitted, a non-linear action at a focal point is an unavoidable phenomenon. In the vicinity of the focal point and beyond, the transmitted pulse itself already has a large amount of the second harmonic component. Have to. Accordingly, second harmonic echoes are generated from sources other than the contrast agent, and cannot be distinguished from echoes from the contrast agent.

In order to make the disturbance due to the nonlinear effect of the transmission pulse less noticeable, the transmission level must be reduced to a fraction of the level used for ordinary imaging, but the magnitude of the secondary effect to be observed is large. Since the power is proportional to the square of the transmission level, lowering the transmission level has a double disadvantage for echo reception.

(2) In some cases, the transmission signal for ultrasonic wave transmission itself contains a frequency component that conflicts with the second harmonic or the reception frequency band of the observation system, and the echo is also the echo of the contrast agent. Indistinguishable.

In order to prevent this, a transmission linear amplifier (linear @ amplifier) or a strict low-pass filter is used for each transducer element of the ultrasonic probe so that such a frequency component is not included in the transmission signal. There is a need.

However, in an electronic scanning ultrasonic probe, as the number of transducer elements increases as the performance becomes higher, it is not possible to use a transmission linear amplifier or a low-pass filter for each of such transducer elements. Simplification, downsizing, and low power consumption are major obstacles.

(3) In imaging using the second harmonic, since a fundamental wave is transmitted and an echo of twice the frequency is received, a broadband ultrasonic probe is required. In order to secure a specific bandwidth, an ultrasonic probe having an ultra-wide band of 130% to 150% in an upper and lower frequency ratio is required. On the other hand, since the specific bandwidth of the ultrasonic probe used for ordinary ultrasonic imaging is about 70%, it cannot be used as it is. Although it is possible to design an ultrasonic probe having a fractional bandwidth exceeding 100%, it is extremely difficult to realize the probe because three to four or more acoustic matching layers are required.

(4) The resonance frequency f0 of the microballoon is relative to the radius r0.

There is a relationship. It is in the not very wide frequency band around this resonance frequency that the microballoon sends back the second harmonic. For this reason, if there is a distribution in the particle diameter of the microballoons, only a part of the distribution contributes to the generation of the nonlinear echo and the efficiency is poor.

(5) When injecting a microballoon contrast agent into a subject and measuring the function of the tissue of interest from the change over time in the concentration, it is necessary to continuously capture the same site over a predetermined time. However, the site of interest easily escapes due to movement of the body tissue, body movement of the subject, and the like, and tracking thereof is not easy.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide an ultrasonic imaging method and apparatus capable of efficiently performing non-linear ultrasonic imaging using a second harmonic, an ultrasonic probe, and an ultrasonic imaging. The realization of the agent.

(1) A first invention for solving the problem is an ultrasonic imaging method that transmits an ultrasonic wave to a subject and uses a second harmonic component of an echo of the ultrasonic wave. A sound wave and an ultrasonic wave having a second intensity substantially 1 / k times the first intensity are alternately transmitted, and an echo based on the ultrasonic wave transmitted at the first intensity and the second ultrasonic wave are transmitted. An echo based on the ultrasonic wave transmitted at the second intensity is received, and a signal obtained by substantially multiplying the echo reception signal based on the ultrasonic wave transmitted at the second intensity by k and the ultrasonic wave transmitted at the first intensity An ultrasonic imaging method using a difference signal from an echo reception signal based on a sound wave.

に お い て In the first invention for solving the problem, it is preferable to set k to 2 in that signal processing becomes easy. In this case, it is preferable that the transmission at the second intensity be performed twice and the reception signal based on the transmission is added twice to substantially double the reception signal in order to reduce noise.

According to the first aspect of the invention for solving the problem, ultrasonic waves are transmitted at two different intensities and the difference between the two types of echo reception signals obtained corresponding to them is obtained. An ultrasonic imaging method capable of extracting an echo from an echo source without using a filter or the like can be realized.

(2) A second invention for solving the problem is an ultrasonic imaging method that transmits an ultrasonic wave to a subject and uses a second harmonic component of an echo of the ultrasonic wave. A sound wave and an ultrasonic wave having a second phase substantially 180 ° different from the first phase are alternately transmitted, and an echo based on the ultrasonic wave transmitted at the first phase and the second phase are transmitted. And an echo based on the ultrasonic wave transmitted at the first phase and the echo received signal based on the ultrasonic wave transmitted at the second phase. The ultrasonic imaging method is characterized by utilizing the above signal.

According to a second aspect of the present invention, there is provided a fourth phase ultrasonic wave having a phase difference of substantially 270 ° from a third phase ultrasonic wave having a phase difference of substantially 90 ° from the first phase. It is preferable to obtain the Doppler signal from the non-linear echo source by transmitting the signals respectively and obtaining the sum signal of the echo reception signals with respect to the ultrasonic waves transmitted at the first to fourth phases.

According to the second aspect of the present invention, the ultrasonic wave is transmitted in a plurality of phases, and the sum of a plurality of echo reception signals obtained corresponding to the plurality of phases is obtained. An ultrasonic imaging method capable of extracting an echo from the object without using a filter or the like can be realized.

(3) A third invention for solving the problem is an ultrasonic imaging method that transmits an ultrasonic wave to a subject and uses a second harmonic component of an echo of the ultrasonic wave. An ultrasonic imaging method characterized by transmitting an ultrasonic wave to a subject based on a transmission signal obtained by synthesizing a signal and a signal having a frequency lower than the fundamental frequency by the predetermined frequency.

According to the third aspect of the present invention, since two frequencies of transmitted ultrasonic waves are mixed in the non-linear echo source, an ultrasonic imaging capable of obtaining an echo signal having a frequency twice the fundamental frequency The method can be realized.

(4) A fourth invention for solving the problem is that an ultrasonic wave is transmitted to a subject, an echo based on the transmitted ultrasonic wave is received, and the echo reception signal is divided by a half wavelength of the fundamental wave. An ultrasonic imaging method characterized in that a signal of a sum of a shifted signal and the echo reception signal is obtained.

According to the fourth aspect of the present invention, it is possible to realize an ultrasonic imaging method capable of eliminating a fundamental wave component and extracting a second harmonic component by adding a half wavelength shift of a fundamental wave.

(5) According to a fifth aspect of the present invention, there is provided an ultrasonic imaging method that transmits an ultrasonic wave to a subject and uses a second harmonic component of an echo of the ultrasonic wave. Are driven by a pair of transmission signals such that the second harmonic components of the vibration frequency have phases that cancel each other out in the transmission beam formed by the ultrasonic waves transmitted from the pair of transducers. And a pair of reception signals are added so that the second harmonic components of the vibration frequency have phases that reinforce each other in a reception beam formed by the reception signals of the pair of transducers. This is an imaging method.

According to the fifth aspect of the present invention, a pair of transducers involved in the formation of an ultrasonic beam are driven by a pair of transmission signals, and a pair of reception signals of the transducers are added. Accordingly, it is possible to realize an ultrasonic imaging method in which the transmitted beam does not include the second harmonic component and the received beam includes only the second harmonic component.

(6) A sixth invention for solving the problem is an ultrasonic imaging method that transmits an ultrasonic wave to a subject and uses a second harmonic component of an echo of the ultrasonic wave. An ultrasonic imaging method characterized in that a displacement of a point of interest in a subject is obtained by dimensional scanning, and a region of interest is tracked based on the displacement of the point of interest.

In a sixth aspect of the present invention for solving the problems, at least once, the inside of the subject is precisely three-dimensionally scanned to obtain a three-dimensional image based on this precise scanning. Scanning and deforming the three-dimensional image based on the displacement of the point of interest is preferable in that a real-time three-dimensional image is obtained.

According to the sixth aspect of the invention for solving the problem, since the region of interest is tracked based on the displacement of the point of interest, the displacement can be tracked for the region of interest whose feature is not clear, and the measurement using the contrast agent can be performed. And an ultrasonic imaging method that can accurately perform the ultrasonic imaging.

(7) According to a seventh aspect of the present invention, there is provided an ultrasonic imaging apparatus that transmits an ultrasonic wave to a subject and uses a second harmonic component of an echo of the ultrasonic wave. A transmitting means for alternately transmitting a sound wave and an ultrasonic wave having a second intensity substantially 1 / k times the first intensity; and an echo based on the ultrasonic wave transmitted at the first intensity. Receiving means for receiving an echo based on the ultrasonic wave transmitted at the second intensity; a signal substantially k times an echo reception signal based on the ultrasonic wave transmitted at the second intensity; And an arithmetic unit for obtaining a signal of a difference from an echo reception signal based on the ultrasonic wave transmitted at the intensity.

(7) In the seventh aspect of the invention for solving the problem, it is preferable to set k to 2 since signal processing becomes easy. In this case, it is preferable that the transmission at the second intensity be performed twice and the reception signal based on the transmission is added twice to substantially double the reception signal in order to reduce noise.

According to the seventh aspect of the present invention, ultrasonic waves are transmitted at two different intensities and the difference between the two types of echo reception signals obtained corresponding to the two intensities is obtained. An ultrasonic imaging apparatus capable of extracting an echo from an echo source without using a filter or the like can be realized.

(8) According to an eighth aspect of the present invention, in an ultrasonic imaging apparatus that transmits an ultrasonic wave to a subject and uses a second harmonic component of an echo of the ultrasonic wave, the subject has an ultrasonic wave having a first phase. Transmitting means for transmitting alternately a sound wave and an ultrasonic wave having a second phase substantially different from the first phase by 180 °; an echo based on the ultrasonic wave transmitted at the first phase; Receiving means for receiving an echo based on the ultrasonic wave transmitted in the second phase; and receiving an echo received signal based on the ultrasonic wave transmitted in the first phase and the ultrasonic wave transmitted in the second phase. And an arithmetic unit for calculating a sum signal based on the received echo signal.

According to an eighth aspect of the present invention, there is provided an ultrasonic wave having a fourth phase substantially different from the first phase by 90 ° from a third phase ultrasonic wave having a phase different from the first phase by 270 °. It is preferable to obtain the Doppler signal from the non-linear echo source, by transmitting the signals respectively and obtaining the sum signal of the echo reception signals corresponding to the ultrasonic waves transmitted at the first to fourth phases.

According to the eighth aspect of the present invention, the ultrasonic wave is transmitted at a plurality of phases and the sum of a plurality of echo reception signals obtained corresponding to the plurality of phases is obtained. An ultrasonic imaging apparatus capable of extracting an echo from the object without using a filter or the like can be realized.

(9) A ninth invention for solving the problem is an ultrasonic imaging apparatus that transmits an ultrasonic wave to a subject and uses a second harmonic component of an echo of the ultrasonic wave. An ultrasonic imaging apparatus comprising: a transmitting unit that transmits an ultrasonic wave based on a transmission signal obtained by combining a signal and a signal having a frequency lower than the fundamental frequency by the predetermined frequency to a subject.

According to the ninth invention for solving the problem, since two frequencies of the transmitted ultrasonic waves are mixed in the nonlinear echo source, an ultrasonic imaging capable of obtaining an echo signal having a frequency twice as much as the fundamental frequency The device can be realized.

(10) A tenth invention for solving the problem is a transmitting means for transmitting an ultrasonic wave to a subject, a receiving means for receiving an echo based on the transmitted ultrasonic wave, and An ultrasonic imaging apparatus comprising: an arithmetic unit for obtaining a signal of a sum of a signal shifted by a half wavelength of the fundamental wave and the echo reception signal.

According to the tenth aspect of the present invention, it is possible to realize an ultrasonic imaging apparatus capable of eliminating a fundamental wave component and extracting a second harmonic component by adding a half wavelength shift of a fundamental wave.

(11) An eleventh invention for solving the problem is directed to an ultrasonic imaging apparatus which transmits an ultrasonic wave to a subject and uses a second harmonic component of an echo of the ultrasonic wave to form a pair of ultrasonic waves related to formation of an ultrasonic beam. Driving with a pair of transmission signals such that the second harmonic components of the vibration frequency have phases that cancel each other out in a transmission beam formed by the ultrasonic waves transmitted from the pair of transducers. Means for adding a pair of reception signals so that the second harmonic components of the oscillation frequency have phases that reinforce each other in a reception beam formed by the reception signals of the pair of transducers. An ultrasonic imaging apparatus characterized in that:

According to the eleventh invention for solving the problem, a pair of transducers involved in the formation of an ultrasonic beam are driven by a pair of transmission signals and a pair of reception signals of the transducers are added. Therefore, it is possible to realize an ultrasonic imaging apparatus in which the transmitted beam does not include the second harmonic component and the received beam includes only the second harmonic component.

(12) A twelfth invention for solving the problem is an ultrasonic imaging apparatus that transmits an ultrasonic wave to a subject and uses a second harmonic component of an echo of the ultrasonic wave. Scanning means for dimensionally scanning, displacement calculating means for calculating a displacement of a point of interest in the subject from an echo received signal, and tracking means for tracking a region of interest based on the displacement of the point of interest. Is an ultrasonic imaging apparatus.

In a twelfth aspect of the present invention for solving the problem, at least one time, the inside of the subject is precisely three-dimensionally scanned to obtain a three-dimensional image based on the precise scanning. Scanning and deforming the three-dimensional image based on the displacement of the point of interest is preferable in that a real-time three-dimensional image is obtained.

According to the twelfth invention for solving the problem, the region of interest is tracked based on the displacement of the point of interest, so that the displacement can be tracked for the region of interest whose feature is not clear, and measurement using a contrast agent can be performed. An ultrasonic imaging apparatus capable of accurately performing the above operation can be realized.

(13) According to a thirteenth invention for solving the problem, a first vibrator having a frequency band including a first frequency and a second vibrator having a frequency band including twice the first frequency are included. An ultrasonic probe characterized by comprising:

In the eleventh invention for solving the problem, it is preferable that the first vibrator and the second vibrator are alternately arranged in order to make the vibrator array uniform. Further, in the thirteenth invention for solving the problem, it is easy to manufacture the vibrator array including an array in which the first vibrators are connected and an array in which the second vibrators are connected. It is preferred in that respect.

According to the thirteenth invention for solving the problem, by providing the first vibrator and the second vibrator, an ultrasonic probe having two frequencies of f0 and 2fo can be realized. .

(14) A fourteenth invention for solving the problem is an ultrasonic contrast agent characterized in that the particle size distribution of the soluble microballoon is substantially within 1: 2. According to the fourteenth invention for solving the problem, since the particle size distribution of the microballoons is 1: 2, it is possible to realize an ultrasonic contrast agent that efficiently generates a nonlinear echo with respect to excitation ultrasonic waves. .

As described above in detail, according to the first aspect of the invention for solving the problem, ultrasonic waves are transmitted at two different intensities, and the difference between the two types of echo reception signals obtained corresponding thereto is transmitted. Is obtained, so that an ultrasonic imaging method capable of extracting an echo from a non-linear echo source without using a filter or the like can be realized.

Further, according to the second aspect of the present invention for solving the problem, ultrasonic waves are transmitted in a plurality of phases, and a sum of a plurality of echo reception signals obtained corresponding to them is obtained. An ultrasonic imaging method capable of extracting an echo from an echo source without using a filter or the like can be realized.

According to the third aspect of the present invention, since two frequencies of the transmitted ultrasonic waves are mixed in the nonlinear echo source, an echo signal having a frequency twice as high as the fundamental frequency can be obtained. A sound wave imaging method can be realized.

According to the fourth aspect of the present invention, an ultrasonic imaging method capable of eliminating a fundamental component and extracting a second harmonic component by adding a half-wave shift of the fundamental component can be realized. .

According to the fifth aspect of the present invention, a pair of transducers involved in the formation of an ultrasonic beam are driven by a pair of transmission signals, and a pair of reception signals of the transducers are added. Accordingly, it is possible to realize an ultrasonic imaging method in which the transmitted beam does not include the second harmonic component and the received beam includes only the second harmonic component.

According to the sixth aspect of the present invention for solving the problem, the region of interest is tracked based on the displacement of the point of interest. Therefore, the displacement can be tracked for a region of interest whose feature is not clear, and the contrast agent can be used. An ultrasonic imaging method capable of accurately performing the measurement can be realized.

According to the seventh aspect of the present invention, ultrasonic waves are transmitted at two different intensities and the difference between the two types of received echo signals obtained corresponding to the two intensities is determined. Thus, an ultrasonic imaging apparatus capable of extracting an echo from a non-linear echo source without using a filter or the like can be realized.

According to the eighth aspect of the present invention for solving the problem, ultrasonic waves are transmitted in a plurality of phases, and the sum of a plurality of echo reception signals obtained corresponding to them is obtained. An ultrasonic imaging apparatus capable of extracting an echo from an echo source without using a filter or the like can be realized.

According to the ninth aspect of the present invention for solving the problem, since two frequencies of the transmitted ultrasonic waves are mixed in the nonlinear echo source, it is possible to obtain an echo signal having a frequency twice the fundamental frequency. A sound wave imaging device can be realized.

According to the tenth aspect of the present invention, it is possible to realize an ultrasonic imaging apparatus capable of erasing a fundamental wave component and extracting a second harmonic component by adding a half wavelength shift of the fundamental wave. .

According to the eleventh invention for solving the problem, a pair of transducers involved in the formation of an ultrasonic beam are driven by a pair of transmission signals and a pair of reception signals of the transducers are added. Accordingly, it is possible to realize an ultrasonic imaging apparatus in which the transmitted beam does not include the second harmonic component and the received beam includes only the second harmonic component.

Further, according to the twelfth invention for solving the problem, since the region of interest is tracked based on the displacement of the point of interest, the displacement can be tracked for the region of interest whose feature is not clear, and the contrast agent can be used. An ultrasonic imaging apparatus capable of accurately performing the measurement can be realized.

According to a thirteenth aspect of the present invention, an ultrasonic probe having two frequencies of f0 and 2fo is provided by providing a first vibrator and a second vibrator. Can be.

According to the fourteenth invention for solving the problems, since the particle size distribution of the microballoons is 1: 2, an ultrasonic contrast agent that efficiently generates a nonlinear echo with respect to the excitation ultrasonic wave is realized. be able to.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
(1) Overall Configuration FIG. 1 shows a block diagram of an ultrasonic diagnostic apparatus. This device is one embodiment of the present invention. Note that an embodiment of the device of the present invention is shown by the configuration of the device. Further, an embodiment of the method of the present invention is shown by the operation of the present apparatus.

In FIG. 1, the ultrasonic probe 1 transmits an ultrasonic beam to an object (not shown) and receives an echo from the object. The ultrasonic probe 1 is an example of an embodiment of the ultrasonic probe according to the present invention. A contrast agent mainly composed of a soluble microballoon is injected into the subject, and ultrasonic imaging is performed based on the contrast agent. The contrast agent will be described later.

The ultrasonic probe 1 has two types of transducer elements having different frequency bands. The frequency band of one vibrator element contains the resonance frequency of the microballoon, and the frequency band of the other vibrator element contains twice the frequency. The ultrasonic probe 1 will be described later.

The transmission / reception unit 2 drives the ultrasonic probe 1 to transmit an ultrasonic beam and receives an echo reception signal of the ultrasonic probe 1. The inside of the subject is scanned by a sound ray formed by the ultrasonic beam. The transmission / reception unit 2 is configured to drive the ultrasonic probe 1 with a transmission signal of a predetermined fundamental frequency and to extract a second harmonic component thereof from a reception signal. The transmitting / receiving unit 2 is an example of an embodiment of the wave transmitting unit, the receiving unit, and the scanning unit in the present invention. The transmitting / receiving unit 2 will be described later.

(4) The echo signal received by the transmitting / receiving unit 2 is processed by the B-mode processing unit 3 to create B-mode image data. The B-mode processing unit 3 can also create M-mode image data by switching operations.

{Circle around (2)} The echo signal received by the transmitting / receiving unit 2 is processed by the Doppler processing unit 4 to create Doppler spectrum data. The Doppler processing includes a pulse Doppler mode and a CW (continuous @ wave) Doppler mode.

{Circle around (2)} The echo signal received by the transmission / reception unit 2 is processed by the color Doppler processing unit 5 to create color Doppler image data. The color Doppler image is also called a CFM (color @ flow @ mapping) image.

The digital scan converter unit 6 inputs a video signal obtained by scan-converting B-mode image data, Doppler spectrum data and color Doppler image data to the display unit 7 and the recording unit 8.

The display unit 7 displays an image based on a video input signal. The recording unit 8 records the video input signal. For example, a video tape recorder (video @ tapercoder) is used as the recording unit 8.

(4) The data processing unit 9 exchanges signals with the above-described units and performs data processing to control the operation of each unit. The data processing unit 9 also measures the tissue function based on the change over time in the density of the contrast agent image. At this time, even when the part of interest is displaced due to body movement or the like, it is automatically tracked. The data processing unit 9 is an example of an embodiment of the displacement detecting means and the tracking means in the present invention. Such displacement detection and tracking will be described later.

(4) The data processing unit 9 includes a computer and a data processing program. Data processing unit 9 also reads and writes data from and to storage unit 10. The storage unit 10 stores three-dimensional image data described later. The operation unit 11 is operated by an operator to provide an input signal and a command signal to the data processing unit 9.

(2) Contrast Agent The reflection intensity at the fundamental wave as a general contrast agent increases as the diameter of the microballoon increases. Therefore, the distribution center of the particle size is around several μm, which is the critical dimension at which embolism occurs in the peripheral blood system. In this case, the optimum irradiation frequency of the ultrasonic wave is 2 to 1 MHz or less, and the frequency of the second harmonic included in the echo falls within the frequency band of the observation system in normal ultrasonic imaging. Therefore, it is better to use an observation system in normal ultrasonic imaging as an observation system, and perform transmission at half the frequency of normal ultrasonic imaging.

と If there is a distribution in the particle diameter of the microballoons, only a part of the distribution contributes to the generation of the non-linear echo and the efficiency is poor. Therefore, a microballoon having a narrow particle diameter distribution (sharp distribution curve) will be used. The particle size distribution is preferably such that the ratio of the minimum value to the maximum value of the diameter is within 1: 2 in order to increase the generation efficiency of the nonlinear echo. Further, when the particle size distribution is narrowed, the frequency distribution of the nonlinear echo is narrowed, which is very convenient for separation by a filter.

(3) Ultrasonic Probe FIG. 2 is a sectional view showing an example of an embodiment of the ultrasonic probe 1. In FIG. 2, a transducer array 101 is provided on a backing material 102. Illustration of the acoustic matching layer and the like is omitted. The vibrator array 101 is configured by arranging two types of vibrator elements a and b alternately.

Note that, as shown in FIG. 3, the vibrator elements a and b may not be alternately arranged, and an array including only the vibrator element a and an array including only the vibrator element b may be arranged in one line.

The configuration of FIG. 2 is preferred in that the two types of transducer elements are uniformly distributed over the entire length of the array. The configuration of FIG. 3 is preferable in that the array can be easily manufactured.
The vibrator element a and the vibrator element b are respectively provided for, for example, 64 channels. One channel may be constituted by one transducer element, or may be constituted by a plurality of transducer elements.

The vibrator elements a and b have different frequency bands. FIG. 4 shows examples of those frequency bands. In FIG. 4, Ba is the frequency band of the vibrator element a, and Bb is the frequency band of the vibrator element b.

付 近 Around the lower limit of the frequency band Ba corresponds to the resonance frequency f0 (for example, 2 MHz) of the micro balloon. The vicinity of the upper limit of the frequency band Bb corresponds to the second harmonic frequency 2f0 (for example, 4 MHz).

Both the bands Ba and Bb have a fractional bandwidth of, for example, 70%. As a result, the high-frequency portion of the band Ba and the low-frequency portion of the band Bb overlap to form a common band Bc.

The transmission of the ultrasonic wave is performed in the band Ba by the array of 64 channels formed by the transducer element a, and the reception of the ultrasonic wave is performed in the band Bb by the array of 64 channels formed by the transducer element b. As a result, the micro balloon is excited by the frequency f 0, and the echo of the second harmonic 2f 0 due to the resonance of the micro balloon is received.

That is, a single ultrasonic probe can handle both the micro balloon excitation frequency and its second harmonic. Needless to say, the transmitting and receiving unit 2 performs beam forming of the ultrasonic wave at the time of transmitting and receiving waves. The echo reception signal is used for forming a B-mode image, a Doppler spectrum image, a CFM image, and the like according to the operation mode.

When performing normal imaging without using microballoons, transmission and reception by only the array of the transducer elements a, transmission and reception by only the array of the transducer elements b, and transmission and reception of the array of the transducer elements a and the transducer elements b The transmission and reception using the array and the array can be performed at the same time.

場合 When transmitting and receiving only by the array of the transducer elements a, the probe can be used as a probe of 64 channels with a frequency band of Ba. When transmitting and receiving only by the array of the transducer elements b, the probe can be used as a probe of 64 channels with a frequency band of Bb. When the array of the vibrator elements a and the array of the vibrator elements b are used at the same time, the probe can be used as a 128-channel probe with a frequency band of Bc.

FIGS. 5 and 6 show another embodiment of the ultrasonic probe 1. FIG. 5 is a plan view, and FIG. 6 is a cross-sectional view along AA. 5 and 6, a disk-shaped vibrator array 103 is provided on a backing material 104. The vibrator array 103 includes two types of vibrator elements a and b.

The vibrator element a and the vibrator element b are formed as fan-shaped vibrating plates, and are alternately arranged on the backing material 104 to form a disk-shaped array as a whole. It is preferable to make the disk-shaped array concave in view of focusing the ultrasonic beam.

For example, an even number (2, 4, 6, 8,...) Of the transducer elements is used as a whole, and is assigned to each of the transducer elements a and b in half. In this case, if each element has the same shape, two sets of probes can be made using all the vibrator elements cut from each disk material without waste, and the utilization rate of the material is increased.

FIGS. 7 to 9 show other forms of the vibrator element arrangement. The arrangement shown in FIG. 7 is such that stripe-shaped transducer elements a and b are alternately arranged. This arrangement is preferable in that the density of the transducer elements is increased. The arrangement shown in FIG. 8 is an arrangement in which dice-shaped transducer elements a and b are arranged in a mosaic pattern (checkered pattern). This arrangement is preferred in that it further increases the density of the transducer elements.

The arrangement shown in FIG. 9 is such that a disk-shaped vibrator element b is concentrically arranged inside an annular vibrator element a. Note that the relationship between the two may be interchanged so that the vibrator element b is formed in an annular shape and the vibrator element a is formed in a disk shape. This arrangement is preferred because of its simple construction.

The vibrator element a has a vibration frequency f0, and the vibrator element b has a vibration frequency 2f0. When a microballoon contrast agent is used, ultrasonic waves are transmitted by the vibrator element a and received waves are transmitted by the vibrator element b. When a micro-balloon contrast agent is not used, transmission and reception using either or both of the transducer elements a and b can be performed.

The ultrasonic probe shown in FIGS. 5 to 9 is most suitable for use as a probe for CW Doppler. Of course, the present invention is not limited to this, and it may be used as a probe for mechanical sector scan or a probe for compound scan.

(4) Transmission / Reception Unit FIG. 10 shows a block diagram of an example of the embodiment of the transmission / reception unit 2 for one channel. A similar configuration is provided for each channel. In FIG. 10, a transmission signal generated from a transmission signal generator 201 is amplified by a transmitter 202, filtered by a filter 203, provided to a transducer element 100 through a transmission / reception switch 204, and transmitted as an ultrasonic wave. It has become. In transmitting a wave, steering or focusing of the transmitted beam is performed by a beamformer (not shown).

The echo signal received by the transducer element 100 is input to the receiver 205 through the transmission / reception switch 204, amplified by the receiver 205, filtered by the filter 206, and subjected to analog / digital conversion by the A / D converter 207. Stored in the memory 208. Upon reception, steering or focusing of the received beam is performed by a beamformer (not shown).

周波 数 The frequency, amplitude, phase, duration, and the like of the transmission signal generated from the transmission signal generator 201 are controlled by the controller 209. The switching of the transmission / reception switch 204 and the operation timing of the A / D converter 207 are also controlled by the controller 209.

The controller 209 is configured by, for example, an MPU (micro processor unit). The controller 209 also performs an operation to be described later on the data stored in the memory 208. The controller 209 is an example of an embodiment of a calculation unit in the present invention.

By switching the output amplitude of the transmission signal generator 201, transmission of 100% amplitude and transmission of 50% amplitude are alternately repeated for the same sound ray, and two types of received signals corresponding to those transmissions are stored in the memory 208. Is stored.

The switching of the transmission wave amplitude may be performed for each sound ray, or may be performed for each ultrasonic scanning frame. It is preferable to perform the operation one by one for each sound ray because the time difference between the two types of transmission is small. Performing it for each frame is preferable in that the frequency switching frequency can be reduced.

{Circle around (2)} For each reception signal of the same sound ray, the controller 209 doubles the reception signal by 50% transmission and obtains the difference from the reception signal by 100% transmission to obtain one reception signal. When the echo sources in the subject are all linear reflection sources, that is, when they return echoes proportional to the transmission amplitude, the received signal by 100% transmission and the reception signal by 50% transmission are doubled. All the frequency components have the same value. Therefore, by calculating the difference between them, not only the fundamental wave component of the transmitted wave but also the harmonic component originally contained in the transmitted wave are canceled and disappear.

On the other hand, when the microballoon contrast agent is present in the subject, the nonlinear component in the echo is proportional to the square of the transmission amplitude, so that the reception signal by 100% transmission and the reception by 50% transmission There is a difference between doubling the signal. Therefore, the echo from such a nonlinear echo source can be obtained by calculating the difference between the two.

That is, it is possible to obtain only the echo from the non-linear echo source without using a filter or the like for extracting the second harmonic. Furthermore, even if a filter for extracting the second harmonic is used, a non-linear component originally included in the transmission system and the reception system that passes through the filter can be removed.

Therefore, it is not necessary to use a transmitter having a particularly high linearity as the transmitter 202 and the receiver 205, and a transmitter used for ordinary ultrasonic imaging may be used as it is. The filters 203 and 206 may be the same as those used for normal ultrasonic imaging, and need not be strict low-pass filters and second harmonic filters. That is, no special transmission / reception mechanism is required for ultrasonic imaging using the second harmonic.

The amplitude of the transmission is not limited to 100% and 50%, but may be a predetermined level and a half thereof. Further, the ratio is not limited to 1/2, but may be an arbitrary ratio 1 / k (k> 1), and the corresponding received signal may be multiplied by k.

{Circle around (2)} Instead of doubling the received signal by the レ ベ ル level transmission, the received signal obtained by transmitting and receiving at the 送 受 信 level twice to the same sound ray may be added. This method is preferable in that a received signal with less noise can be obtained by an averaging effect of noise by addition.

FIG. 11 shows a block diagram of another example of the embodiment of the transmission / reception unit 2 for one channel. In FIG. 11, the same parts as those in FIG. In FIG. 11, a demodulator 210 is inserted between the filter 206 and the A / D converter 207, so that the received signal is demodulated at the frequency 2f0.

(4) By switching the output phase of the transmission signal generator 201 by the controller 209, the transmission of 0 ° phase and the transmission of 180 ° phase of the frequency f0 are alternately repeated for the same sound ray. The switching of the transmission phase may be performed for each frame of the ultrasonic scanning.

(2) The two types of received signals corresponding to these transmissions are demodulated at 2f0 by the demodulator 210, converted to digital signals by the A / D converter 207, and stored in the memory 208. The controller 209 obtains the sum of the received signal for the 0 ° phase transmission and the received signal for the 180 ° phase transmission to obtain one reception signal.

As the received signal is demodulated at 2f0, the received signal corresponding to the 0 ° phase transmission and the reception signal corresponding to the 180 ° phase transmission have opposite polarities with respect to the fundamental frequency component in the demodulated signal. So they are offset by taking the sum.

On the other hand, for the second harmonic component, the 180 ° phase shift of the fundamental frequency f0 corresponds to the 360 ° phase shift, so that the demodulated signal and the received signal corresponding to the 0 ° transmission have a 180 ° phase shift. The received signals corresponding to the transmitted waves have the same polarity and are doubled by taking the sum. That is, the fundamental frequency component of the echo is canceled out and the second harmonic component reinforces, so that an echo of only the second harmonic can be obtained without using a special filter. The above situation is shown in FIG.

In other words, the Fourier transform of the pulse signal of frequency f0 generated at a constant repetition period PRT (pulse @ repetition @ time) as shown in FIG. 13 is as shown in FIG. The spectrum and the frequency 2f0 part are arranged in an order that exactly matches. Here, the spectrum interval is PRF (pulse @ repetition @ frequency). PRF is the reciprocal of PRT.

On the other hand, when the phase of the pulse is inverted for each PRT as in this embodiment (FIG. 15), the frequency spectrum becomes as shown in FIG. That is, the second harmonic 2f0 has an odd order of the PRF, and no spectrum exists at the position of the fundamental frequency f0.

However, if there is a Doppler shift in the fundamental frequency component, that portion is not canceled and remains as a Doppler signal. Therefore, the present embodiment can be applied not only to the use of extracting the second harmonic component for the B mode but also to the use of extracting the Doppler shift component of the fundamental frequency component for the Doppler mode.

When the CW Doppler mode is performed, a continuous wave having a frequency f0 is generated in the transmission signal generator 201 as shown in FIG. 17, and its phase is switched between 0 ° and 180 ° at a constant cycle. At this time, in order to prevent aliasing, it is necessary to make 逆 of the reciprocal (corresponding to PRF) of the cycle of the phase switching sufficiently larger than the Doppler shift to be detected.

As another example of the embodiment of the transmission, there is a method of transmitting the transmission signal of the fundamental frequency f0 four times to the same sound ray while changing the phase by 90 °. That is, the signals are sequentially transmitted at phases of 0 °, 90 °, 180 °, and 270 °. Then, each echo reception signal is demodulated at 2f0, digitized and stored in the memory 208, and then the four reception signals are fully added.

In this case, 90 ° of the fundamental frequency f0 is equivalent to 180 ° of the second harmonic, so that the four harmonics are canceled out by adding all four received signals in addition to the fundamental frequency component. This situation is shown in FIG.

(4) At this time, if there is a Doppler shift in the second harmonic component, the component remains without being canceled even by full addition of the four signals. That is, the present embodiment mainly extracts the Doppler shift of the second harmonic. However, a component having a Doppler shift of the fundamental frequency is extracted.

When the CW Doppler mode is performed, a continuous wave having a frequency f0 is generated in the transmission signal generator 201 as shown in FIG. 19, and its phase is switched between 0 °, 90 °, 180 °, and 270 ° at a constant cycle. . At this time, it is necessary to prevent the aliasing by making the half of the reciprocal (corresponding to the PRF) of the phase switching period sufficiently larger than the Doppler shift to be detected.

FIG. 20 shows another form of the transmission signal when the CW Doppler mode is performed for the second harmonic component. The transmission signal shown in FIG. 20 is obtained by combining two signals having frequencies f0 + Δf and f0−Δf.

(4) When this signal is applied to the nonlinear echo source, mixing of the frequencies f0 + Δf and f0−Δf is performed due to the nonlinearity, and an echo of the frequency 2fo is obtained. This state is shown in FIG. 21 by a spectrum.

As shown in FIG. 21, since the transmission signal does not include the fundamental frequency f0 according to such transmission / reception, CW Doppler measurement on the second harmonic component is performed without any means for removing the fundamental frequency f0. be able to. Also in this case, it is necessary to prevent the aliasing by making Δf / 2 sufficiently larger than the Doppler shift to be detected.

FIG. 22 shows a block diagram of another example of the embodiment of the transmission / reception unit 2 for one channel. In FIG. 22, the same parts as those in FIG. In FIG. 22, a fundamental wave remover 211 is inserted between the A / D converter 207 and the memory 208, whereby the component of the fundamental frequency f0 is removed from the received signal.

As shown in FIG. 23, the fundamental wave remover 211 adds the sum of the signal passed through the delay circuit 212 having a delay time corresponding to a half wavelength (λ / 2) of the fundamental wave and the signal not passed through the delay circuit 212 to an adder. 213. The delay circuit 212 is realized by, for example, a shift register or the like.

The phase of the fundamental wave component changes by 180 ° through the delay circuit 212, but the second harmonic component changes by 360 °. Therefore, when these are added to the input signal which is not delayed, the fundamental wave components cancel each other out, and the second harmonic component is doubled. That is, extraction of the second harmonic is performed.

Note that an analog fundamental wave remover can be configured by using an analog delay circuit for the delay circuit 212 and an analog adder for the adder 213. In that case, the fundamental wave remover is provided before the A / D converter 207.

The fundamental wave remover 211 may be realized by the function of the controller 209. That is, regarding the received signals stored in the memory 208, signals of the same sound ray may be shifted by a half wavelength of the fundamental wave and added by the controller 209. As a result, the fundamental component can be eliminated and the second harmonic component can be extracted. This is convenient because the hardware of the fundamental wave remover 211 can be omitted.

FIG. 24 shows a block diagram of another example of the embodiment of the transmission / reception unit 2 for two adjacent channels. Similar channel pairs are provided for all transducers of the ultrasonic probe 1. 24, the same parts as those in FIG. 10 are denoted by the same reference numerals, and description thereof will be omitted.

Here, these two channels are a pair of channels related to the formation of the transmitted and received ultrasonic beams. In both channels, the transmission signal generator 201 (201 ') to the transmission / reception changeover switch 204 (204') and the controller 209 are an example of an embodiment of the driving means in the present invention. Further, the controller 209 is an example of an embodiment of the adding means in the present invention.

The controller 209 controls the transmission signal generators 201 and 201 'to provide a phase difference corresponding to 90 [deg.] Of the fundamental wave between the transmission signals generated by them. As a result, ultrasonic waves having such a phase difference are transmitted from the vibrators 100 and 100 ′, respectively.

The ultrasonic waves transmitted from the vibrators 100 and 100 'are subjected to beam forming by a beamformer (not shown) so as to have the same sound ray or focus. However, the 90 ° phase difference is not impaired by beam forming.

As a method of giving a phase difference equivalent to 90 ° of the fundamental wave, a method of making the waveforms of the transmission signals generated by the transmission signal generators 201 and 201 ′ have a phase difference of 90 ° with respect to the same waveform There is a method of giving a time difference corresponding to a phase difference of 90 °. The latter is preferable in that it can be easily realized.

Alternatively, the positions of the ultrasonic wave radiating surfaces of the vibrators 100 and 100 'are made different from each other in the traveling direction of the ultrasonic wave by a distance corresponding to 90 [deg.] Of the fundamental wave, namely, a quarter wavelength ([lambda] / 4) of the fundamental wave. May be. In this case, it is preferable that the phases of the transmission signals generated by the transmission signal generators 201 and 201 'do not need to be changed.

位相 A phase difference corresponding to 90 ° of the fundamental wave is a 180 ° phase difference with respect to the second harmonic. For this reason, even if the second harmonic component is contained in the ultrasonic waves transmitted from the transducers 100 and 100 ', they cancel each other out in the transmitted beam and disappear. Therefore, an ultrasonic source consisting of only the fundamental wave (and the third harmonic) is irradiated to the echo source in the subject. In this way, the second harmonic component can be removed from the transmitted ultrasonic wave without using a filter.

The echo signals received by the 'oscillators 100 and 100' are received by respective receiving systems and stored in the memories 208 and 208 '. Upon reception, beamforming of received waves, that is, beam steering, focusing, and the like are performed by a beamformer (not shown).

With respect to the echo reception signal, the reception signal stored in each of the memories 208 and 208 ′ is added by the controller 209 with a phase difference corresponding to 180 ° of the fundamental wave.

As a result, the fundamental wave components of the received signal cancel each other out, and on the other hand, the second harmonic component has a phase difference equivalent to 180 ° of the fundamental wave of 360 ° and has the same phase. . That is, a received signal consisting of only the second harmonic can be obtained. Thus, the echo of the second harmonic can be extracted without using a filter.

In addition, when the transducers 100 and 100 ′ whose ultrasonic radiation planes are shifted by λ / 4 of the fundamental wave are used, there is already a phase difference of 90 ° of the fundamental wave between the two received signals, so that there is a further difference. The echo of the second harmonic can be extracted by adding and adding a phase difference of 90 °.

(5) Three-Dimensional Imaging and Tracking of Tissue Displacement FIG. 25 shows how the ultrasonic probe 1 scans the inside of the subject. As the ultrasonic probe 1, a probe having a two-dimensional array of transducer elements is used. The transmission / reception unit 2 controls the beam forming of the ultrasonic probe 1 to scan the inside of the subject three-dimensionally.

At least the first three-dimensional scan of the subject is performed by sound rays sufficiently dense to obtain a desired spatial resolution, and a B-mode image is formed by the B-mode processing unit 3 based on the received signal. Then, the B mode image data is stored in the storage unit 10 by the data processing unit 9. Thereby, the storage unit 10 holds a three-dimensional image (still image) having a desired spatial resolution.

注目 The attention point is determined for this three-dimensional image. As a point of interest, for example, as shown in FIG. 26, a corner, a high-luminance part, an interface in a distance direction orthogonal to the sound ray, an interface in an azimuth direction parallel to the sound ray, and the like are selected. A few or more than ten points of interest are sufficient.

The point of interest is determined manually or automatically. In the case of manual operation, the operator specifies on the image displayed on the display unit 7. In the automatic case, the data processing unit 9 performs edge detection from the image data by secondary differentiation or the like, and extracts an interface parallel to an interface orthogonal to the sound ray by Hough transformation or the like from the edge detection. For example, a point of interest is determined at a point where the differential value becomes maximum.

(4) The data processing unit 9 controls the transmission / reception unit 2 to cause the next and subsequent scans to be performed only on these points of interest. Since such scanning can be performed by using several tens of sound rays, scanning can be performed in real time.

A three-dimensional image is formed based on the received signal and stored in the storage unit 10. This three-dimensional image indicates the current position of the point of interest.
By the way, the tissue in the subject does not occur or disappear within a short time even if the tissue is displaced or deformed, and the order of the arrangement does not change. Therefore, by estimating the deformation amount of the three-dimensional image from the displacement of the point of interest and deforming the precise three-dimensional image obtained first according to it, the three-dimensional image representing the state in the subject at that time can be obtained with a relatively good approximation. An image can be obtained.

FIG. 27 is a diagram illustrating an image deformation. Note that, for convenience of description, the expression is reduced to two dimensions. The transformation of the image is performed as follows.
(1) An original image with a normal sound ray density is obtained by the first scan (FIG. 27A).
(2) The position of the point of interest is obtained by the next coarse scanning, and the new position of the point of interest is compared with the original position (FIG. 27B).
(3) A vector indicating the displacement of the target point from the original position is obtained (FIG. 27C).
(4) The obtained vectors are extrapolated to obtain displacement vectors for all pixels of the image (FIG. 27D).
(5) The original image is deformed based on the displacement vectors of all the pixels to be the current image (FIG. 27E).

The scanning of the point of interest, the calculation of the displacement vector, and the deformation of the original image can be performed in a much shorter time than the three-dimensional scanning at the normal sound ray density. Therefore, a three-dimensional image with a desired spatial resolution can be obtained in real time by deforming the original image as described above.

Hereinafter, a real-time three-dimensional image can be obtained by repeating scanning of only the target point and deformation of the original image according to the displacement of the target point. Then, by displaying this image on the display unit 7, real-time three-dimensional image display can be performed. In addition, it is preferable that the original image is deformed by using a table for converting the read address of the image data and rewriting the address conversion table according to the displacement vector in terms of speeding up.

(4) It is preferable to retake the original image at regular intervals in order to obtain a three-dimensional image more faithful to the actual situation. In addition, instead of always performing the transformation of the original image, the transformation of the image immediately before the transformation may be performed.

(4) Since the displacement of the point of interest is always tracked as described above, even if the injection site of the contrast agent is displaced due to body motion or the like, the location of the point of interest can be tracked based on the displacement of the point of interest. Therefore, it is possible to always measure the density value of the contrast agent at the current position of the site. As a result, accurate measurement can be performed for the first time, and a measurement curve of a contrast agent as shown in FIG. 28 can be obtained.

It is a block diagram of an example of an embodiment of the invention. FIG. 1 is a diagram illustrating a configuration of an ultrasonic probe according to an example of an embodiment of the present invention. FIG. 1 is a diagram illustrating a configuration of an ultrasonic probe according to an example of an embodiment of the present invention. FIG. 3 is a diagram illustrating a frequency characteristic of an ultrasonic probe according to an example of an embodiment of the present invention. FIG. 1 is a diagram illustrating a configuration of an ultrasonic probe according to an example of an embodiment of the present invention. FIG. 1 is a diagram illustrating a configuration of an ultrasonic probe according to an example of an embodiment of the present invention. FIG. 1 is a diagram illustrating a configuration of an ultrasonic probe according to an example of an embodiment of the present invention. FIG. 1 is a diagram illustrating a configuration of an ultrasonic probe according to an example of an embodiment of the present invention. FIG. 1 is a diagram illustrating a configuration of an ultrasonic probe according to an example of an embodiment of the present invention. FIG. 2 is a block diagram of a transmission / reception unit in the device according to the example of the embodiment of the present invention. FIG. 2 is a block diagram of a transmission / reception unit in the device according to the example of the embodiment of the present invention. FIG. 3 is an explanatory diagram of an operation of a transmission / reception unit in the device according to the example of the embodiment of the present invention; FIG. 3 is an explanatory diagram of an operation of a transmission / reception unit in the device according to the example of the embodiment of the present invention; FIG. 3 is an explanatory diagram of an operation of a transmission / reception unit in the device according to the example of the embodiment of the present invention; FIG. 3 is an explanatory diagram of an operation of a transmission / reception unit in the device according to the example of the embodiment of the present invention; FIG. 3 is an explanatory diagram of an operation of a transmission / reception unit in the device according to the example of the embodiment of the present invention; FIG. 3 is an explanatory diagram of an operation of a transmission / reception unit in the device according to the example of the embodiment of the present invention; FIG. 3 is an explanatory diagram of an operation of a transmission / reception unit in the device according to the example of the embodiment of the present invention; FIG. 3 is an explanatory diagram of an operation of a transmission / reception unit in the device according to the example of the embodiment of the present invention; FIG. 3 is an explanatory diagram of an operation of a transmission / reception unit in the device according to the example of the embodiment of the present invention; FIG. 3 is an explanatory diagram of an operation of a transmission / reception unit in the device according to the example of the embodiment of the present invention; FIG. 2 is a block diagram of a transmission / reception unit in the device according to the example of the embodiment of the present invention. It is a block diagram of a fundamental wave removal part in an example of an embodiment of the invention. FIG. 2 is a block diagram of a transmission / reception unit in the device according to the example of the embodiment of the present invention. FIG. 3 is a conceptual diagram of three-dimensional scanning in the apparatus according to the embodiment of the present invention. It is a conceptual diagram of the attention point in the apparatus of an example of Embodiment of this invention. FIG. 2 is a conceptual diagram of image processing in the device according to the embodiment of the present invention; It is a graph which shows the time change of the measured value in the measurement using a contrast agent.

Explanation of reference numerals

100, 200, 300 Ultrasound diagnostic apparatus 1 Ultrasonic probe 2 Transmitter / receiver 3 Quadrature detector 4 Power calculator 5, 25 Blood flow image generator 6 Display 11 Timer 12, 34 Operation unit 21 Power peak hold unit 22 Last power / elapsed time storage unit 31 Synchronization unit 32 Power / elapsed time storage unit 33 Blood flow image generation unit by display mode 331 Through mode processing unit 332 Peak hold mode processing unit 333 Inflow threshold hold mode processing unit 334 Outflow threshold hold mode processing Unit 335 superimposition mode processing unit 336 monochrome mode processing unit 337 hue gradation mode processing unit 35 switch

Claims (3)

In an ultrasonic imaging apparatus that transmits an ultrasonic wave to a subject and uses a second harmonic component of the echo, the ultrasonic wave having a first phase differs from the first phase by substantially 180 ° to the subject. A transmitting means for transmitting the ultrasonic wave of the second phase alternately; and an echo based on the ultrasonic wave transmitted at the first phase and an echo based on the ultrasonic wave transmitted at the second phase. Receiving means for receiving, and calculating means for obtaining a signal of a sum of an echo received signal based on the ultrasonic wave transmitted at the first phase and an echo received signal based on the ultrasonic wave transmitted at the second phase. An ultrasonic imaging apparatus, comprising: In an ultrasonic imaging apparatus that transmits an ultrasonic wave to a subject and uses the second harmonic component of the echo, a pair of transducers involved in forming an ultrasonic beam are transmitted from the pair of transducers. Driving means driven by a pair of transmission signals so that the second harmonic components of the vibration frequency in the transmission beam formed by the ultrasonic waves have mutually canceling phases, and reception signals of the pair of transducers are formed. An ultrasonic imaging apparatus comprising: an adder that adds a pair of received signals so that second harmonic components of an oscillation frequency in a received beam have mutually reinforcing phases. Transmitting means for transmitting an ultrasonic wave to a subject; receiving means for receiving an echo based on the transmitted ultrasonic wave; a signal obtained by shifting the echo received signal by a half wavelength of the fundamental wave; and the echo received signal And an operation means for obtaining a signal of the sum of

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