JPH09131344A - Ultrasonic image picking-up method, device, ultrasonic probe, and ultrasonic contrast medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently pick up a nonlinear ultrasonic image by utilizing the difference between the signal practically multiplied with the echo reception signal based on the ultrasonic wave transmitted at the second intensity by (k) and the echo reception signal based on the ultrasonic wave transmitted at the first intensity. SOLUTION: A transmission/reception section 2 drives an ultrasonic probe 1 with the transmission signal having the prescribed fundamental frequency and extracts the second harmonic component. The ultrasonic wave having the first intensity and the ultrasonic wave having the second intensity which is 1/k times the first intensity are transmitted in turn to an object, and the echoes based on the ultrasonic waves transmitted at each intensity are received. The echo from a nonlinear echo source is extracted without using a filter by utilizing the difference signal between the signal multiplied with the echo reception signal based on the ultrasonic wave transmitted at the second intensity by (k) and the echo reception signal based on the ultrasonic wave transmitted at the first intensity.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an ultrasonic imaging method and apparatus, an ultrasonic probe and an ultrasonic contrast agent. More specifically, it relates to an ultrasonic imaging method and apparatus for an echo source having a nonlinear ultrasonic reflection characteristic, an ultrasonic probe, and an ultrasonic contrast agent.

[0002]

2. Description of the Related Art In recent years, a second harmonic imaging method utilizing the resonant non-linear response of microbubbles to ultrasonic waves has been investigated. In addition, a contrast agent containing soluble microballoons as a main component has been developed.

The second harmonic imaging method utilizes the fact that microbubbles contained in a contrast agent generate an echo containing the second harmonic of the irradiated ultrasonic wave due to its resonant non-linear response. . This echo is about 1 of the Doppler signal
It has a sensitivity of 00 times. An image of the injection site of the contrast agent is formed based on the received echo of the second harmonic, and the function of the tissue of interest is measured based on the temporal change in the concentration of the contrast agent.

[0004]

[Problems to be solved by the invention]

(1) In the ultrasonic imaging apparatus, since the focused wave front of ultrasonic waves is transmitted, a non-linear effect at the focal point is an unavoidable phenomenon, and the transmitted pulse itself already has a large amount of the second harmonic component near and beyond the focal point. I have Therefore,
As a result, second-harmonic echoes are generated from other than the contrast agent and cannot be distinguished from the echo from the contrast agent.

In order to make the interference due to the non-linear effect of the transmitted wave pulse inconspicuous, the transmitted wave level must be reduced to a fraction of the level normally used for imaging, but the secondary level to be observed is desired. Since the magnitude of the effect is proportional to the square of the transmission level, lowering the transmission level has a double disadvantage for echo reception.

(2) The transmission signal itself for ultrasonic wave transmission may itself contain a frequency component that interferes with the second harmonic wave or the reception frequency band of the observation system, and its echo is also imaged. Indistinguishable from the echo of the drug.

To prevent this, a linear amplifier for transmission (linear amplifier) is provided for each transducer element of the ultrasonic probe.
It is necessary to use r) or a strict low-pass filter to prevent the transmission signal from containing such frequency components.

However, in an electronic scanning type ultrasonic probe, a higher number of transducer elements are used as the performance becomes higher. Therefore, a transmission linear amplifier or a low-pass filter is used for each of such a large number of transducer elements. This is a major obstacle to the simplification, miniaturization and low power consumption of the device.

(3) In imaging with the second harmonic,
Since the fundamental wave is transmitted and the echo of the double frequency is received, a wide band ultrasonic probe is required. 130% to 1 in the upper and lower frequency ratios if the ratio bandwidth is secured.
It requires as much as 50% ultra wideband ultrasonic probe. On the other hand, since the specific bandwidth of the ultrasonic probe used for normal ultrasonic imaging is about 70%, it cannot be used as it is. It is possible to design an ultrasonic probe having a specific bandwidth exceeding 100%, but it is very difficult to realize because of the need for 3 to 4 or more acoustic matching layers.

(4) The resonance frequency f _{0 of the} microballoon is relative to the radius r ₀

[0011]

(Equation 1)

[0012] There is a relationship. It is in the not so wide frequency band around this resonance frequency that the microballoon sends back the second harmonic. For this reason, if the particle diameters of the microballoons are distributed, only a part of the particle diameters contributes to the generation of the nonlinear echo, and the efficiency is poor.

(5) When a microballoon contrast agent is injected into a subject and the function of the tissue of interest is measured from the change in its concentration over time, the same site must be continuously captured for a predetermined time. However, due to movements of internal tissues and body movements of the subject, the target area easily escapes and tracking is difficult.

The present invention has been made to solve the above-mentioned problems, and an object thereof is an ultrasonic imaging method and apparatus, an ultrasonic probe contactor, and an ultrasonic imaging contact which can efficiently perform nonlinear ultrasonic imaging by the second harmonic. It is to realize an ultrasonic contrast agent.

[0015]

[Means for Solving the Problems]

(1) A first invention for solving the problem is an ultrasonic imaging method for transmitting an ultrasonic wave to a subject and utilizing a second harmonic component of an echo thereof, wherein 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 An echo based on the ultrasonic wave transmitted with the intensity, and a signal obtained by substantially multiplying the echo reception signal based on the ultrasonic wave transmitted with the second intensity by k and the ultrasonic wave transmitted with the first intensity. It is an ultrasonic imaging method characterized by utilizing a signal of a difference from an echo reception signal based on a sound wave.

In the first invention for solving the problem, it is preferable to set k to 2 in order to facilitate signal processing. In this case, the transmission with the second intensity is performed twice,
Substantially doubling by adding two received signals based on it is preferable in terms of reducing noise.

According to the first invention for solving the problem, ultrasonic waves are transmitted with two kinds of intensities, and a difference between two kinds of echo reception signals obtained corresponding to them is obtained. Therefore, it is possible to realize an ultrasonic imaging method capable of extracting an echo from a non-linear echo source without using a filter or the like.

(2) A second invention for solving the problem is to provide an ultrasonic imaging method in which an ultrasonic wave is transmitted to a subject and the second harmonic component of the echo is used, and the first subject is applied to the subject. An ultrasonic wave having a phase and an ultrasonic wave having a second phase which is 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 first phase are transmitted. And an echo based on the ultrasonic wave transmitted in the second phase,
The ultrasonic imaging method is characterized in that a signal of a sum of an echo reception signal based on an ultrasonic wave transmitted in the phase 2 and an echo reception signal based on an ultrasonic wave transmitted in the second phase is used.

In a second invention for solving the problem, a fourth phase which is substantially 270 ° different from an ultrasonic wave of a third phase which is substantially 90 ° different in phase from the first phase.
It is preferable from the viewpoint of obtaining the Doppler signal from the non-linear echo source to transmit the ultrasonic wave of each phase and obtain the sum signal of the echo reception signals for the ultrasonic waves transmitted in the first to fourth phases.

According to the second invention for solving the problem, the 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 method that can extract an echo from a nonlinear echo source without using a filter or the like can be realized.

(3) A third invention for solving the problem is an ultrasonic imaging method for transmitting an ultrasonic wave to a subject and utilizing a second harmonic component of an echo thereof, wherein a predetermined frequency is lower than a fundamental frequency. The ultrasonic imaging method is characterized in that an ultrasonic wave based on a transmission signal obtained by combining a signal of a high frequency and a signal of a frequency lower than the fundamental frequency by the predetermined frequency is transmitted to the subject.

According to the third invention for solving the problem, since the two frequencies of the transmitted ultrasonic waves are mixed in the non-linear echo source, an echo signal having a frequency twice the fundamental frequency can be obtained. An ultrasonic imaging method can be realized.

(4) A fourth invention for solving the problem is to transmit an ultrasonic wave to a subject, receive an echo based on the transmitted ultrasonic wave, and output the echo reception signal of its fundamental wave. In the ultrasonic imaging method, a sum signal of a signal shifted by a half wavelength and the echo reception signal is obtained.

According to the fourth invention for solving the problem, an ultrasonic imaging method capable of eliminating the fundamental wave component and extracting the second harmonic component by adding half-wavelength shifts of the fundamental wave is realized. it can.

(5) A fifth invention for solving the problem is to form an ultrasonic beam in an ultrasonic imaging method which transmits an ultrasonic wave to a subject and utilizes the second harmonic component of its echo. For the pair of transducers involved, a pair of transmission signals such that the second harmonic component of the oscillation frequency has a phase that cancels each other in the transmission beam formed by the ultrasonic waves transmitted from the pair of transducers. Driven by the above 1
The ultrasonic imaging method is characterized by adding a pair of reception signals so that the second harmonic components of the vibration frequency have a mutually reinforcing phase in the reception beam formed by the reception signals of the pair of transducers. .

According to the fifth 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 driven. Since the addition is performed, 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 to provide an ultrasonic imaging method in which an ultrasonic wave is transmitted to a subject and the second harmonic component of the echo is used to detect the ultrasonic wave inside the subject. The ultrasonic imaging method is characterized in that a displacement of a point of interest in a subject is obtained by three-dimensionally scanning with a beam, and a region of interest is tracked based on the displacement of the point of interest.

In the sixth invention for solving the problem, the inside of the subject is precisely three-dimensionally scanned at least once to obtain a three-dimensional image based on the precise scanning, and thereafter, the attention inside the subject is noted. It is preferable to scan only the points and deform the three-dimensional image based on the displacement of the point of interest in order to obtain a real-time three-dimensional image.

According to the sixth invention for solving the problem, since the region of interest is tracked based on the displacement of the point of interest, it is possible to track the displacement of the region of interest in which the feature is not clear, and the contrast agent is used. An ultrasonic imaging method capable of accurately performing the used measurement can be realized.

(7) A seventh invention for solving the problem is an ultrasonic imaging apparatus which transmits an ultrasonic wave to a subject and utilizes the second harmonic component of the echo of the ultrasonic wave. A transmitting means for alternately transmitting an ultrasonic wave having a high intensity and an ultrasonic wave having a second intensity which is substantially 1 / k times the first intensity; and an ultrasonic wave transmitted at the first intensity. Based echo and the second
Receiving means for receiving an echo based on the ultrasonic wave transmitted with the intensity of, and a signal obtained by substantially multiplying the echo reception signal based on the ultrasonic wave transmitted with the second intensity by k and the first intensity. An ultrasonic imaging apparatus comprising: an arithmetic unit that obtains a signal of a difference from an echo reception signal based on the transmitted ultrasonic wave.

In the seventh invention for solving the problem, it is preferable to set k to 2 because the signal processing becomes easy. In this case, the transmission with the second intensity is performed twice,
Substantially doubling by adding two received signals based on it is preferable in terms of reducing noise.

According to the seventh invention for solving the problem, ultrasonic waves are transmitted with two kinds of intensities, and a difference between two kinds of echo reception signals obtained corresponding to them is obtained. Therefore, it is possible to realize an ultrasonic imaging apparatus that can extract an echo from a nonlinear echo source without using a filter or the like.

(8) An eighth invention for solving the problem is an ultrasonic imaging apparatus which transmits an ultrasonic wave to a subject and utilizes the second harmonic component of the echo of the ultrasonic wave. Based on the transmitting means for alternately transmitting the ultrasonic wave of the phase and the ultrasonic wave of the second phase which is substantially 180 ° different from the first phase, and the ultrasonic wave transmitted in the first phase. Receiving means for receiving an echo and an echo based on the ultrasonic wave transmitted in the second phase, and an echo reception signal based on the ultrasonic wave transmitted in the first phase and transmitted in the second phase An ultrasonic imaging apparatus comprising: an arithmetic unit that obtains a sum signal of an echo reception signal based on ultrasonic waves.

In an eighth invention for solving the problem, an ultrasonic wave of a third phase which is substantially 90 ° out of phase with the first phase and a fourth phase which is substantially 270 ° out of phase with the ultrasonic wave of the third phase.
It is preferable in terms of obtaining a Doppler signal from a non-linear echo source to transmit the ultrasonic wave of each phase and obtain the sum signal of the echo reception signals of the ultrasonic waves transmitted in the first to fourth phases. .

According to the eighth invention for solving the problem, ultrasonic waves are transmitted at a plurality of phases, and the sum of a plurality of echo reception signals obtained corresponding to them is obtained. It is possible to realize an ultrasonic imaging apparatus that can extract an echo from a nonlinear echo source without using a filter or the like.

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

According to the ninth invention for solving the problem, since the two frequencies of the transmitted ultrasonic waves are mixed in the non-linear echo source, an echo signal having a frequency twice the fundamental frequency can be obtained. An ultrasonic imaging device can be realized.

(10) A tenth aspect of the present 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 the echo. An ultrasonic imaging apparatus comprising: an arithmetic means for calculating a sum signal of a signal obtained by shifting a received signal by a half wavelength of its fundamental wave and the echo received signal.

According to the tenth invention for solving the problems, an ultrasonic imaging apparatus capable of eliminating the fundamental wave component and extracting the second harmonic component by adding the half-wavelength shifts of the fundamental wave is realized. it can.

(11) An eleventh invention for solving the problem is to form an ultrasonic beam in an ultrasonic imaging apparatus which transmits an ultrasonic wave to a subject and utilizes the second harmonic component of its echo. With respect to the pair of transducers involved, the pair of transmission signals are arranged so that the second harmonic components of the oscillation frequency have phases canceling each other in the transmission beam formed by the ultrasonic waves transmitted from the pair of transducers. Drive means for driving, and adder means for adding the pair of received signals so that the second harmonic components of the oscillation frequency are in mutually reinforcing phases in the received beam formed by the received signals of the pair of oscillators. An ultrasonic imaging apparatus comprising:

According to the eleventh aspect of the invention for solving the problem, a pair of transducers involved in forming an ultrasonic beam are driven by a pair of transmission signals and a pair of reception signals of the transducers are driven. Since the addition is performed, 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 for transmitting an ultrasonic wave to a subject and utilizing the second harmonic component of the echo, wherein the ultrasonic wave is transmitted through the subject. A scanning means for three-dimensionally scanning with a beam, a displacement calculation means for obtaining a displacement of a target point in the subject from an echo reception signal, and a tracking means for tracking a region of interest based on the displacement of the target point. It is an ultrasonic imaging apparatus characterized by the above.

In a twelfth aspect of the 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 this precise scanning. It is preferable to scan only the points and deform the three-dimensional image based on the displacement of the point of interest in order to obtain a real-time three-dimensional image.

According to the twelfth invention for solving the problem, since the region of interest is traced based on the displacement of the point of interest, it is possible to trace the displacement of the region of interest in which the feature is not clear, and the contrast agent is used. It is possible to realize an ultrasonic imaging apparatus capable of accurately performing the measurement used.

(13) A thirteenth invention for solving the problem is to provide a first oscillator having a frequency band including a first frequency and a frequency band including a frequency twice the first frequency. An ultrasonic probe contact, comprising: a second vibrator having the same.

In the eleventh invention for solving the problem, it is preferable that the first vibrator and the second vibrator are arranged in a staggered manner in order to make the vibrator array uniform. In addition, in the thirteenth invention for solving the problem, it is easy to manufacture that the transducer array is composed of an array in which the first transducers are connected and an array in which the second transducers are connected. It is preferable in terms.

According to the thirteenth invention for solving the problem, by providing the first vibrator and the second vibrator,
An ultrasonic probe contact having two frequencies of f ₀ and 2f _o can be realized.

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

[0049]

BEST MODE FOR CARRYING OUT THE INVENTION 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 an embodiment of the present invention. It should be noted that the configuration of the present apparatus shows an embodiment relating to the apparatus of the present invention. Also, the operation of the apparatus shows an embodiment relating to the method of the present invention.

In FIG. 1, an ultrasonic probe 1 transmits an ultrasonic beam to a subject (not shown) and receives an echo from the subject. 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 soluble microballoons is injected into the subject, and ultrasonic imaging is performed based on this contrast agent. The contrast agent will be described later.

The ultrasonic probe 1 has different frequency bands 2
It has transducer elements of different types. The frequency band of one transducer element includes the resonance frequency of the microballoon, and the frequency band of the other transducer element includes twice the frequency. The ultrasonic probe 1 will be described later again.

The transmitting / receiving section 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 the acoustic rays formed by the ultrasonic beam. The transmission / reception unit 2 is configured to drive the ultrasonic probe 1 with a transmission signal having a predetermined fundamental frequency and extract the second harmonic component thereof from the reception signal. The transmitting / receiving section 2 is an example of an embodiment of the wave transmitting means, the receiving means and the scanning means in the present invention. The transmitter / receiver 2 will be described later.

The echo signal received by the transmission / reception unit 2 is processed by the B-mode processing unit 3 to produce B-mode image data. The B-mode processing unit 3 can also create M-mode image data by switching the operation.

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

The echo signal received by the transmitting / receiving section 2 is processed by the color Doppler processing section 5 to produce color Doppler image data. Color Doppler image is CFM (color
Also called flow mapping image.

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

The display section 7 displays an image based on a video input signal. The recording unit 8 records a video input signal. As the recording unit 8, for example, a video tape recorder is used.

The data processing unit 9 sends and receives signals to and from each of the above 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 temporal change in the concentration of the contrast agent image. At that time, even if the region 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 again.

The data processing unit 9 is composed of a computer and a data processing program. The data processing unit 9 also reads and writes data from the storage unit 10.
The storage unit 10 stores three-dimensional image data described later.
The operation unit 11 is operated by an operator and supplies 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 particle size distribution center is set to 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 ultrasonic waves is 2 to 1
The frequency of the second harmonic contained in the echo is in the frequency band of the observation system in normal ultrasonic imaging. Therefore, it is preferable to use an observation system for normal ultrasonic imaging as the observation system and to perform transmission at half the frequency of normal ultrasonic imaging.

If the particle size of the microballoon is distributed, only a part of the particle size contributes to the generation of the non-linear echo and the efficiency is low. Therefore, the microballoon having a narrow particle size distribution (sharp distribution curve) is used. . Regarding the distribution of particle diameters, it is preferable that the ratio of the minimum value to the maximum value of the diameter is within 1: 2 from the viewpoint of increasing the generation efficiency of the nonlinear echo. Further, if the particle size distribution is narrowed, the frequency distribution of the non-linear echo becomes narrowed, which is extremely 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, the transducer array 101 is provided on the backing material 102. Illustration of the acoustic matching layer and the like is omitted. The vibrator array 101 is configured by arranging two kinds of vibrator elements a and b alternately.

It should be noted that the transducer elements a and b may not be staggered, and as shown in FIG. 3, an array of only the transducer elements a and an array of only the transducer elements b may be arranged in one row.

The configuration of FIG. 2 is preferable 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 because the array can be easily manufactured. The vibrator element a and the vibrator element b are provided for 64 channels each, for example. One channel may be composed of one vibrator element, or may be composed of a plurality of vibrator elements.

The transducer elements a and b have different frequency bands. An example of those frequency bands is shown in FIG. In FIG. 4, Ba is the transducer element a
, And Bb is the frequency band of the transducer element b.

The vicinity of the lower limit of the frequency band Ba corresponds to the resonance frequency f ₀ (for example, 2 MHz) of the microballoon. The vicinity of the upper limit of the frequency band Bb corresponds to the frequency 2f ₀ (for example, 4 MHz) of the second harmonic.

Each of the bands Ba and Bb has a specific bandwidth of, for example, 70%. As a result, the high band part of the band Ba and the low band part of the band Bb overlap to form the common band Bc.

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

That is, both the microballoon excitation frequency and its second harmonic can be handled by a single ultrasonic probe. Needless to say, the ultrasonic wave beamforming is performed by the transmitting / receiving unit 2 when transmitting and receiving waves. The echo reception signal is a B-mode image, a Doppler spectrum image, a CFM depending on the operation mode.
Used for forming images.

When performing normal imaging without using a microballoon, transmission / reception by only the array of transducer elements a, transmission / reception by only the array of transducer elements b, and the array of transducer elements a and the transducers are performed. Transmission and reception can be performed using the array of elements b at the same time.

In the case of performing transmission / reception with only the array of transducer elements a, it can be used as a probe of 64 channels having a frequency band of Ba. In the case of performing transmission / reception with only the array of transducer elements b, it can be used as a probe of 64 channels with a frequency band of Bb. When the array of transducer elements a and the array of transducer elements b are used at the same time, they can be used as probes of 128 channels with a frequency band of Bc.

Another embodiment of the ultrasonic probe 1 is shown in FIG.
And shown in FIG. FIG. 5 is a plan view and FIG. 6 is a sectional view taken along line AA. In FIGS. 5 and 6, a disk-shaped transducer array 103 is provided on the backing material 104. The transducer array 103 includes two types of transducer elements a and b.
Composed of

Transducer element a and transducer element b
Are formed as fan-shaped vibrating plates, and are alternately arranged on the backing material 104 to form a disc-shaped array as a whole. It is preferable to make the disk-shaped array concave so as to focus the ultrasonic beam.

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

Another form of the transducer element array is shown in FIGS.
As shown in FIG. In the arrangement shown in FIG. 7, stripe-shaped transducer elements a and b are arranged alternately. This arrangement is preferable because it increases the density of the transducer elements. The array shown in FIG. 8 is an array of the transducer elements a and b in the shape of a dice, arranged in a mosaic pattern (checkered pattern). This arrangement is preferable because it further increases the density of the transducer elements.

In the arrangement shown in FIG. 9, the disk-shaped vibrator elements b are concentrically arranged inside the annular vibrator element a. The relationship between the two may be exchanged, and the vibrator element b may have an annular shape and the vibrator element a may have a disk shape. This arrangement is preferable because of its simple structure.

The vibrator element a has a vibration frequency f ₀ , and the vibrator element b has a vibration frequency 2f.
_{It has 0} . When a microballoon contrast agent is used, the ultrasonic wave is transmitted by the transducer element a and the ultrasonic wave is received by the transducer element b. When the microballoon contrast agent is not used, transmission / reception can be performed using either or both of the transducer elements a and b.

The ultrasonic probe shown in FIGS. 5 to 9 is suitable for use as a probe for CW Doppler. Of course, the 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, the transmission signal generated from the transmission signal generator 201 is amplified by the transmitter 202, filtered by the filter 203, given to the transducer element 100 through the transmission / reception changeover switch 204, and transmitted as an ultrasonic wave. It has become. In addition,
In transmitting the wave, steering or focusing of the transmitted beam is performed by a beam former (not shown).

The echo signal received by the transducer element 100 is passed through the transmission / reception changeover switch 204 to the receiver 205.
Input to the receiver 206, amplified by the receiver 205, and filtered by the filter 206.
Are filtered by the A / D converter 207 and are analog / digital converted by the A / D converter 207 and stored in the memory 208. Upon reception, steering or focusing of the received beam is performed by a beam former (not shown).

The frequency, amplitude, phase, duration, etc. of the transmission signal generated from the transmission signal generator 201 are determined by the controller 2
It is controlled by 09. The controller 209 also controls the switching of the transmission / reception switch 204 and the operation timing of the A / D converter 207.

The controller 209 is, for example, an MPU (micro
processor unit). Controller 2
09 also performs a calculation as will be described later on the data stored in the memory 208. The controller 209 is an example of an embodiment of the calculating means in the present invention.

By switching the output amplitude of the transmission signal generator 201, the transmission of 100% amplitude and the transmission of 50% amplitude are alternately repeated for the same sound ray, and 2 corresponding to these transmissions.
The received signal of the type is stored in the memory 208.

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

The controller 209 doubles the received signal of 50% transmission for each received signal of the same sound ray to obtain 100%.
The difference from the received signal due to the wave transmission is calculated and used as the received signal for one time. When the echo sources in the subject are all linear reflection sources, that is, when returning an echo proportional to the amplitude of the transmitted wave, the received signal by 100% transmission and the received signal by 50% transmission are doubled. All the frequency components have the same value as the one that was done. Therefore, by obtaining the difference between the two, not only the fundamental wave component of the transmitted wave but also the harmonic component originally included in the transmitted wave are canceled and disappear.

On the other hand, when the microballoon contrast agent is present in the subject, the non-linear component in the echo is proportional to the square of the amplitude of the transmitted wave. There is a difference between the received signal due to the wave and the doubled signal. Therefore, an echo from such a non-linear echo source can be obtained by obtaining the difference between the two.

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

Therefore, the transmitter 202 and the receiver 2
As 05, it is not necessary to use one having particularly good linearity, and one used for normal ultrasonic imaging may be used as it is. Further, as the filters 203 and 206, those used for normal ultrasonic imaging may be used as they are,
It need not be a strict low pass filter and a second harmonic filter respectively. That is, no special transmission / reception mechanism is required for ultrasonic imaging with the second harmonic.

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

Further, instead of doubling the received signal by 1/2 level transmission, the received signals obtained by performing transmission / reception at 1/2 level twice on the same sound ray may be added. . This method is preferable in that a received signal with less noise can be obtained by the averaging effect of noise due to addition.

FIG. 11 shows a block diagram of another example of the embodiment of the transmitting / receiving section 2 for one channel. FIG.
In FIG. 10, the same parts as those in FIG. In FIG. 11, filter 206 and A
A demodulator 210 is inserted between the / D converters 207, whereby the received signal is demodulated at the frequency 2f ₀ .

By switching the output phase of the transmission signal generator 201 by the controller 209, the 0 ° phase transmission and the 180 ° phase transmission of the frequency f ₀ are alternately repeated for the same sound ray. The switching of the transmission phase may be performed in units of ultrasonic scanning frames.

Two types of received signals corresponding to those transmitted waves are demodulated at 2f ₀ by the demodulator 210 and the A / D converter 2
At 07, it is converted into a digital signal and stored in the memory 208. The controller 209 calculates the sum of the reception signal for the 0 ° phase transmission and the reception signal for the 180 ° phase transmission, and sets the sum as one reception signal.

Since the received signal is demodulated at 2f ₀ , the fundamental frequency component of the demodulated signal is 0.
Since the reception signal corresponding to the wave transmission of the ° phase and the reception signal corresponding to the wave transmission of the 180 phase have the opposite polarities, they are canceled by taking the sum.

On the other hand, for the second harmonic component, a 180 ° phase shift of the fundamental frequency f ₀ corresponds to a 360 ° phase shift, so that the received signal corresponding to the 0 ° phase transmission in the demodulated signal is The reception signals corresponding to the 180 ° phase transmission have the same polarity and are multiplied by taking the sum. That is, since the fundamental frequency component of the echo is canceled and the second harmonic component is strengthened, the second harmonic component is strengthened without using a special filter.
It is possible to obtain echoes of only harmonics. The above situation is shown in FIG.

From a different point of view, as shown in FIG. 13, a constant repetition period PRT (pulse repetition timing)
The Fourier transform of the pulse signal of frequency f ₀ generated in e) is as shown in FIG. 14, and the frequency spectrum of the frequency f ₀ portion and the frequency spectrum of the frequency 2f ₀ portion are arranged in the order of exactly matching. Here, the spectrum interval is P
RF (pulse repetition frequency). PRF is P
It is the reciprocal of RT.

On the other hand, when the phase of the pulse is inverted every PRT as in the present embodiment (FIG. 15), the frequency spectrum becomes as shown in FIG. That is, the second harmonic 2f ₀ becomes an odd order of PRF, and the spectrum does not exist at the position of the fundamental frequency f ₀ .

However, when the fundamental frequency component has a Doppler shift, the Doppler shift is not canceled and remains as a Doppler signal.
Therefore, the present embodiment can be applied to not only the application of extracting the second harmonic component for the B mode but also the application of extracting the Doppler shift component of the fundamental frequency component for the Doppler mode.

When carrying out the CW Doppler mode,
As shown in FIG. 7, the transmission signal generator 201 is caused to generate a continuous wave of frequency f ₀ , and its phase is set to 0 ° and 180 ° at a constant cycle.
Switch to ° and. At this time, in order to prevent aliasing, 1/2 of the reciprocal of the phase switching period (corresponding to PRF) needs to be sufficiently larger than the Doppler shift to be detected.

As another example of the wave transmission embodiment, there is also a method of changing the phase of the transmission signal of the fundamental frequency f ₀ by 90 ° and transmitting it to the same sound ray four times each. That is, 0 °, 90
The waves are sequentially transmitted in phases of 180, 180 and 270 degrees. Then, each echo reception signal is set to 2f _0.
Are demodulated and digitized and stored in the memory 208, and then the four received signals are fully added.

In this case, 90 ° of the fundamental frequency f ₀ is the second
Since this corresponds to 180 ° of the harmonic, the four received signals are fully added to cancel the second harmonic component in addition to the fundamental frequency component. This situation is shown in FIG.

At this time, if the second harmonic component has a Doppler shift, that 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, the component having the Doppler shift of the fundamental frequency is extracted.

When carrying out the CW Doppler mode,
As shown in FIG. 9, the transmission signal generator 201 is caused to generate a continuous wave of frequency f ₀ , and the phase thereof is set to 0 ° and 90 ° at a constant cycle.
Switch to °, 180 ° and 270 °. At this time, 1/2 of the reciprocal of the phase switching period (corresponding to PRF) needs to be sufficiently larger than the Doppler shift to be detected to prevent aliasing.

FIG. 20 shows another form of the transmission signal when the CW Doppler mode is executed for the second harmonic component. The transmission signal shown in FIG. 20 has frequencies f ₀ + Δf and f ₀ −.
It is a combination of two signals of Δf.

When this signal is applied to the non-linear echo source, mixing of the frequencies f ₀ + Δf and f ₀ -Δf is performed due to the non-linearity, and an echo of frequency 2f _o is obtained. This state is shown by the spectrum in FIG.

As shown in FIG. 21, since the transmission signal does not include the fundamental frequency f ₀ according to such transmission and reception, the second frequency is eliminated without any means for removing it.
CW Doppler measurement regarding harmonic components can be performed. Also in this case, Δf / 2 needs to be sufficiently larger than the Doppler shift to be detected to prevent aliasing.

FIG. 22 shows a block diagram of another example of the embodiment of the transmitting / receiving section 2 for one channel. FIG.
In FIG. 10, the same parts as those in FIG. In FIG. 22, the A / D converter 207
The fundamental wave eliminator 211 is inserted between the memory 208 and the memory 208, whereby the component of the fundamental frequency f ₀ is eliminated from the received signal.

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

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

By using an analog delay circuit as the delay circuit 212 and an analog adder as the adder 213, an analog fundamental wave remover can be constructed. In that case, the fundamental wave remover is provided in front of the A / D converter 207.

The fundamental wave remover 211 is a controller 209.
You may make it implement | achieve by the function of. That is,
With respect to the received signal stored in the memory 208, the signals of the same sound ray may be shifted by the half wavelength of the fundamental wave and added by the controller 209. As a result, the fundamental wave 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 transmitting / receiving section 2 for two adjacent channels.
Similar channel pairs are provided for all transducers of the ultrasonic probe 1. In FIG. 24, the same parts as those in FIG.

Here, these two channels are a pair of channels involved in formation of ultrasonic waves for transmission and reception. Transmit signal generator 20 for both channels
1 (201 ′) to transmission / reception changeover switch 204 (20
4 ') and the controller 209 are an example of an embodiment of the driving means in the present invention. Controller 2
Reference numeral 09 is an example of an embodiment of the adding means in the present invention.

The controller 209 is the transmission signal generator 20.
1 and 201 'are controlled to give a phase difference corresponding to 90 ° of the fundamental wave between the transmission signals generated by them. As a result, the oscillators 100 and 10
The ultrasonic waves having such a phase difference are transmitted from 0 '.

A beam former (not shown) allows
The ultrasonic waves transmitted from the vibrators 100 and 100 'are subjected to beam forming processing so that they have the same sound ray or focus. However, due to beam forming,
The phase difference of 0 ° is not impaired.

The method of giving the phase difference corresponding to 90 ° of the fundamental wave is the same as the method of making the waveforms of the transmission signals generated by the transmission signal generators 201 and 201 ′ have a phase difference of 90 °. There is a method of giving a time difference corresponding to a phase difference of 90 ° with respect to the waveform of. The latter is preferable because it is easy to realize.

Alternatively, if the positions of the ultrasonic wave emitting surfaces of the transducers 100 and 100 'are different from each other in the traveling direction of ultrasonic waves by 90 ° of the fundamental wave, that is, a distance corresponding to a quarter wavelength (λ / 4) of the fundamental wave. You may allow it. In this case, it is preferable not to change the phase of the transmission signal generated by the transmission signal generators 201 and 201 '.

The phase difference corresponding to 90 ° of the fundamental wave is 180 ° with respect to the second harmonic. Therefore, the ultrasonic waves transmitted from the oscillators 100 and 100 'are
Even if harmonic components are included, they cancel each other out in the transmitted beam and disappear. Therefore, the echo source in the subject is irradiated with ultrasonic waves consisting only of the fundamental wave (and the third harmonic). 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 transducers 100 and 100 'are received by the respective receiving systems and stored in the memories 208 and 208'. Upon reception, a beam former (not shown) performs received beam forming, that is, beam steering and focusing.

The memory 208 stores the echo reception signal.
The received signals stored in the respective signals 208 and 208 'are 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 and disappear. On the other hand, for the second harmonic component, the phase difference corresponding to 180 ° of the fundamental wave becomes 360 ° and becomes the same phase. Doubling by. That is, it is possible to obtain a received signal composed of only the second harmonic. In this way, the echo of the second harmonic can be extracted without using a filter.

When the oscillators 100 and 100 ′ whose ultrasonic wave emitting surfaces are deviated by λ / 4 of the fundamental wave are used, the phase difference of 90 ° of the fundamental wave is already present between the two received signals. Therefore, 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, one having a two-dimensional array of transducer elements is used. Transmitter / receiver 2
Controls the beam forming of the ultrasonic probe 1 to scan the inside of the subject three-dimensionally.

The three-dimensional scanning of the inside of the subject is performed at least once at the first time with a sound ray sufficiently dense to obtain a desired spatial resolution, and the B mode processing unit 3 performs the B mode by the received signal. An image is formed, and the B-mode image data is stored in the storage unit 10 by the data processing unit 9. As a result, the storage unit 10 has a desired spatial resolution of 3
A three-dimensional image (still image) is held.

A target point is determined for this three-dimensional image. As an attention point, for example, as shown in FIG.
A corner portion, a high-luminance portion, an interface in the distance direction orthogonal to the sound ray, an interface in the azimuth direction parallel to the sound ray, etc. are selected. It suffices if these points are a few points or a dozen points.

The attention point is determined manually or automatically. In the case of manual operation, the operator designates 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 quadratic differentiation or the like, extracts Huff (Hough) transformation or the like from the interface, and extracts an interface parallel to the sound ray, and extracts those interfaces. For example, the point of interest is set to the point where the differential value becomes maximum.

The data processing section 9 controls the transmitting / receiving section 2 so that the next and subsequent scans will be performed only for these points of interest. Since such scanning can be performed with several tens of sound rays, scanning can be performed in real time.

A three-dimensional image is formed based on the received signal,
It is stored in the storage unit 10. This three-dimensional image shows the current position of the point of interest. By the way, the tissue in the subject is
Even if there is displacement or deformation, it does not occur or disappear within a short period of time, and the order of arrangement is not changed. Therefore, if the amount of deformation of the three-dimensional image is estimated from the displacement of the point of interest and the precise three-dimensional image initially obtained is deformed accordingly, the three-dimensional image representing the state inside the subject at that time can be obtained with relatively good approximation. You can get a statue.

FIG. 27 shows an explanatory diagram of image deformation. It should be noted that, for convenience of description, it is expressed in a two-dimensionally degenerate manner. The image transformation is performed as follows. An original image with a normal sound ray density is obtained by the first scanning (FIG. 27A). The position of the point of interest is obtained by the next rough scanning, and the new position of the point of interest is compared with the original position (FIG. 27).
(B)). A vector indicating the displacement of the point of interest from the original position is obtained (FIG. 27 (c)). The obtained vector is extended and interpolated to obtain displacement vectors for all pixels of the image (FIG. 27 (d)). The original image is transformed based on the displacement vectors of all the pixels to obtain the current image (FIG. 27 (e)).

The scanning of the target point, 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 with the regular sound ray density. Therefore, by modifying the original image as described above, a three-dimensional image with a desired spatial resolution can be obtained in real time.

Hereinafter, a real-time three-dimensional image can be obtained by repeatedly scanning only the target point and deforming 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. 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 in accordance with the displacement vector in terms of speeding up.

Further, it is preferable that the original image is retaken at regular intervals in order to obtain a three-dimensional image more faithful to the actual condition. Further, the image deformation may be performed not only on the original image but on the image immediately before the deformation.

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 movement or the like, its location can be tracked based on the displacement of the point of interest. Therefore, it is possible to constantly measure the concentration value of the contrast agent at the current position of the site. Only by this, accurate measurement can be performed and, for example, a measurement curve of the contrast agent as shown in FIG. 28 can be obtained.

[0134]

As described above in detail, according to the first invention for solving the problems, ultrasonic waves are transmitted with two kinds of intensities, and two kinds of waves obtained corresponding to them are transmitted. Since the difference between the echo reception signals is obtained, it is possible to realize an ultrasonic imaging method capable of extracting the echo from the nonlinear echo source without using a filter or the like.

According to the second 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. Therefore, it is possible to realize an ultrasonic imaging method capable of extracting an echo from a non-linear echo source without using a filter or the like.

Further, according to the third invention for solving the problem, since the two frequencies of the transmitted ultrasonic waves are mixed in the non-linear echo source, it is possible to obtain an echo signal having a frequency twice the fundamental frequency. It is possible to realize an ultrasonic imaging method capable of performing the above.

According to the fourth invention for solving the problem, an ultrasonic imaging method capable of eliminating the fundamental wave component and extracting the second harmonic component by adding half-wavelength shifts of the fundamental wave. Can be realized.

Further, according to the fifth invention for solving the problem, a pair of transducers involved in the formation of an ultrasonic beam is driven by a pair of transmission signals and a pair of receptions of those transducers is performed. Since the signals are added, 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 invention for solving the problem, since the region of interest is tracked based on the displacement of the point of interest, it is possible to track the displacement of the region of interest whose features are not clear, and It is possible to realize an ultrasonic imaging method capable of accurately performing measurement using an agent.

According to the seventh invention for solving the problem, ultrasonic waves are transmitted with two kinds of intensities, and the difference between two kinds of echo reception signals obtained corresponding to them is obtained. Therefore, it is possible to realize an ultrasonic imaging apparatus capable of extracting an echo from a nonlinear echo source without using a filter or the like.

Further, according to the eighth 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 thereto is obtained. Therefore, it is possible to realize an ultrasonic imaging apparatus that can extract an echo from a nonlinear echo source without using a filter or the like.

Further, according to the ninth invention for solving the problem, since the two frequencies of the transmitted ultrasonic waves are mixed in the non-linear echo source, it is possible to obtain an echo signal having a frequency twice the fundamental frequency. It is possible to realize an ultrasonic imaging apparatus capable of performing the above.

According to the tenth aspect of the invention for solving the problem, an ultrasonic imaging apparatus capable of eliminating the fundamental wave component and extracting the second harmonic component by adding half-wavelength shifts of the fundamental wave. Can be realized.

According to the eleventh aspect of the invention for solving the problem, a pair of transducers involved in forming an ultrasonic beam is driven by a pair of transmission signals and a pair of transducers receives the pair of transducers. Since the signals are added, 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 in which the feature is not clear, and It is possible to realize an ultrasonic imaging apparatus that can accurately perform measurement using an agent.

According to the thirteenth invention for solving the problem, by providing the first vibrator and the second vibrator, the ultrasonic probe contact having two frequencies of f ₀ and 2f _o is provided. The child can be realized.

According to the fourteenth invention for solving the problem, since the particle diameter distribution of the microballoon is set to 1: 2, an ultrasonic contrast agent which efficiently generates a nonlinear echo with respect to the excited ultrasonic wave. Can be realized.

[Brief description of the drawings]

FIG. 1 is a block diagram of an apparatus according to an example of an embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of an ultrasonic probe according to an example of an embodiment of the present invention.

FIG. 3 is a diagram showing a configuration of an ultrasonic probe according to an example of an embodiment of the present invention.

FIG. 4 is a diagram showing frequency characteristics of the ultrasonic probe according to the example of the embodiment of the present invention.

FIG. 5 is a diagram showing a configuration of an ultrasonic probe according to an example of an embodiment of the present invention.

FIG. 6 is a diagram showing a configuration of an ultrasonic probe according to an example of an embodiment of the present invention.

FIG. 7 is a diagram showing a configuration of an ultrasonic probe according to an example of an embodiment of the present invention.

FIG. 8 is a diagram showing a configuration of an ultrasonic probe according to an example of an embodiment of the present invention.

FIG. 9 is a diagram showing a configuration of an ultrasonic probe according to an example of an embodiment of the present invention.

FIG. 10 is a block diagram of a transmission / reception unit in the apparatus according to the exemplary embodiment of the present invention.

FIG. 11 is a block diagram of a transmission / reception unit in the apparatus according to the exemplary embodiment of the present invention.

FIG. 12 is an operation explanatory diagram of the transmission / reception unit in the apparatus according to the example of the embodiment of the present invention.

FIG. 13 is an operation explanatory diagram of the transmission / reception unit in the apparatus according to the example of the embodiment of the present invention.

FIG. 14 is an operation explanatory diagram of the transmission / reception unit in the apparatus according to the example of the embodiment of the present invention.

FIG. 15 is an operation explanatory diagram of the transmission / reception unit in the apparatus according to the example of the embodiment of the present invention.

FIG. 16 is an operation explanatory diagram of the transmission / reception unit in the apparatus according to the example of the embodiment of the present invention.

FIG. 17 is an operation explanatory diagram of the transmission / reception unit in the apparatus according to the example of the embodiment of the present invention.

FIG. 18 is an operation explanatory diagram of the transmission / reception unit in the apparatus according to the example of the embodiment of the present invention.

FIG. 19 is an operation explanatory diagram of the transmission / reception unit in the apparatus according to the example of the embodiment of the present invention.

FIG. 20 is an operation explanatory diagram of the transmission / reception unit in the apparatus according to the example of the embodiment of the present invention.

FIG. 21 is an operation explanatory diagram of the transmission / reception unit in the apparatus according to the example of the embodiment of the present invention.

FIG. 22 is a block diagram of a transmission / reception unit in the apparatus of the example of the embodiment of the present invention.

FIG. 23 is a block diagram of a fundamental wave removing unit in an apparatus according to an example of an embodiment of the present invention.

FIG. 24 is a block diagram of a transmission / reception unit in an apparatus according to an example of an embodiment of the present invention.

FIG. 25 shows 3 in the apparatus according to the embodiment of the present invention.
It is a conceptual diagram of dimensional scanning.

FIG. 26 is a conceptual diagram of a target point in the apparatus according to the exemplary embodiment of the present invention.

FIG. 27 is a conceptual diagram of image processing in the apparatus according to the example of the embodiment of the present invention.

FIG. 28 is a graph showing a change over time in measured values in measurement using a contrast agent.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ultrasonic probe 2 Transmission / reception part 3 B mode processing part 4 Doppler processing part 5 Color Doppler processing part 6 Digital scan converter part 7 Display part 8 Recording part 9 Data processing part 10 Storage part 11 Operation part 101,103 Transducer array 102, 104 backing material 100 oscillator 201 transmission signal generator 202 transmitter 203, 206 filter 204 transmission / reception switch 205 receiver 207 A / D converter 208 memory 209 controller 210 demodulator 211 fundamental wave remover 212 delay circuit 213 addition vessel

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[Procedure amendment]

[Submission date] December 26, 1995

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Name of invention

[Correction method] Change

[Correction contents]

Title: Ultrasonic imaging method and apparatus, ultrasonic probe and ultrasonic contrast agent

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] Claim 13

[Correction method] Change

[Correction contents]

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0001

[Correction method] Change

[Correction contents]

[0001]

TECHNICAL FIELD The present invention relates to an ultrasonic imaging method and apparatus, an ultrasonic probe, and an ultrasonic contrast agent. More specifically, it relates to an ultrasonic imaging method and apparatus for an echo source having a nonlinear ultrasonic reflection characteristic, an ultrasonic probe and an ultrasonic contrast agent.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0014

[Correction method] Change

[Correction contents]

The present invention has been made to solve the above problems, and an object thereof is an ultrasonic imaging method and apparatus, an ultrasonic probe, and an ultrasonic imaging method capable of efficiently performing nonlinear ultrasonic imaging by the second harmonic. It is to realize an ultrasonic contrast agent.

[Procedure Amendment 5]

[Document name to be amended] Statement

[Name of item to be corrected] 0045

[Correction method] Change

[Correction contents]

(13) A thirteenth invention for solving the problem is to provide a first vibrator having a frequency band including a first frequency and a frequency band including a frequency twice the first frequency. An ultrasonic probe comprising: a second oscillator having the same.

[Procedure correction 6]

[Document name to be amended] Statement

[Correction target item name] 0047

[Correction method] Change

[Correction contents]

According to the thirteenth invention for solving the problem, the ultrasonic probe having two frequencies of f ₀ and 2f _o is provided by including the first vibrator and the second vibrator. Can be realized.

[Procedure amendment 7]

[Document name to be amended] Statement

[Correction target item name] 0146

[Correction method] Change

[Correction contents]

According to the thirteenth invention for solving the problems, the ultrasonic probe having two frequencies of f ₀ and 2f _o is provided by including the first vibrator and the second vibrator. The child can be realized.

Claims (14)

[Claims] 1. An ultrasonic imaging method for transmitting ultrasonic waves to a subject and utilizing the second harmonic component of the echo, wherein the subject has substantially the same ultrasonic intensity as the first intensity. To 1
/ K times an ultrasonic wave having a second intensity is alternately transmitted, and an echo based on the ultrasonic wave transmitted at the first intensity and an echo based on the ultrasonic wave transmitted at the second intensity are transmitted. A signal of a difference between the echo reception signal based on the ultrasonic wave transmitted at the second intensity and substantially multiplied by k and the echo reception signal based on the ultrasonic wave transmitted at the first intensity is received. An ultrasonic imaging method characterized by being used. 2. In an ultrasonic imaging method, wherein ultrasonic waves are transmitted to a subject and the second harmonic component of the echo is used, the ultrasonic waves of the first phase and the first phase are substantially present on the subject. By alternately transmitting ultrasonic waves of a second phase that differ by 180 °,
An echo reception signal based on the ultrasonic wave transmitted in the first phase, which receives an echo based on the ultrasonic wave transmitted in the first phase and an echo based on the ultrasonic wave transmitted in the second phase And an echo reception signal based on an ultrasonic wave transmitted in the second phase is used as a signal, which is an ultrasonic imaging method. 3. An ultrasonic imaging method for transmitting an ultrasonic wave to a subject and utilizing the second harmonic component of the echo, wherein a signal having a frequency higher than a fundamental frequency by a predetermined frequency and only the predetermined frequency higher than the fundamental frequency. An ultrasonic imaging method comprising transmitting an ultrasonic wave to a subject based on a transmission signal obtained by combining a low-frequency signal. 4. An ultrasonic wave is transmitted to a subject, an echo based on the transmitted ultrasonic wave is received, and a signal obtained by shifting the echo reception signal by a half wavelength of the fundamental wave and the echo reception signal are used. An ultrasonic imaging method using a sum signal. 5. An ultrasonic imaging method for transmitting an ultrasonic wave to a subject and utilizing a second harmonic component of an echo thereof, wherein the pair of transducers involved in forming an ultrasonic beam is
The transmission beam formed by the ultrasonic waves transmitted from the pair of oscillators is driven by the pair of transmission signals so that the second harmonic components of the vibration frequency have a phase that cancels each other out, and the pair of vibrations is generated. An ultrasonic imaging method, characterized in that a pair of reception signals are added so that the second harmonic component of the vibration frequency has a mutually reinforcing phase in the reception beam formed by the reception signal of the child. 6. An ultrasonic imaging method, wherein ultrasonic waves are transmitted to a subject and the second harmonic component of the echo is used, the inside of the subject is three-dimensionally scanned with an ultrasonic beam. An ultrasonic imaging method characterized in that a displacement of a point of interest is obtained, and a region of interest is tracked based on the displacement of the point of interest. 7. An ultrasonic imaging apparatus that transmits an ultrasonic wave to a subject and uses the second harmonic component of its echo, wherein the subject has an ultrasonic wave of a first intensity and a substantial intensity of the first intensity. To 1
/ K times an ultrasonic wave having a second intensity of ultrasonic waves alternately transmitted, an echo based on the ultrasonic wave transmitted at the first intensity, and an ultrasonic wave transmitted at the second intensity Receiving means for receiving an echo based on the ultrasonic wave, and a echo reception signal based on the ultrasonic wave transmitted at the first intensity and a signal obtained by substantially multiplying an echo reception signal based on the ultrasonic wave transmitted at the second intensity. An ultrasonic imaging apparatus comprising: an arithmetic unit that obtains a signal of a difference from the signal. 8. An ultrasonic imaging apparatus that transmits ultrasonic waves to a subject and uses the second harmonic component of the echo thereof, wherein the ultrasound of the first phase and the first phase are substantially present on the subject. Transmitting means for alternately transmitting ultrasonic waves of a second phase different from each other by 180 °, an echo based on the ultrasonic waves transmitted in the first phase, and ultrasonic waves transmitted in the second phase Receiving means for receiving an echo based on the ultrasonic wave, and a signal of a sum of an echo received signal based on the ultrasonic wave transmitted in the first phase and an echo received signal based on the ultrasonic wave transmitted in the second phase. An ultrasonic imaging apparatus, comprising: a calculating unit for calculating. 9. An ultrasonic imaging apparatus for transmitting an ultrasonic wave to a subject and utilizing a second harmonic component of an echo thereof, wherein a signal having a frequency higher than a fundamental frequency by a predetermined frequency and only the predetermined frequency above the fundamental frequency. An ultrasonic imaging apparatus comprising: a transmitting unit configured to transmit an ultrasonic wave to a subject based on a transmission signal obtained by combining a low-frequency signal. 10. 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 a signal obtained by shifting the echo reception signal by a half wavelength of its fundamental wave. And an arithmetic means for calculating a sum signal of the echo reception signal. 11. An ultrasonic imaging apparatus that transmits an ultrasonic wave to a subject and uses the second harmonic component of the echo of the ultrasonic wave, wherein the pair of transducers involved in the formation of an ultrasonic beam is the one described above.
Drive means for driving with a pair of transmission signals so that the second harmonic components of the vibration frequency have a phase that cancels each other in the transmission beam formed by the ultrasonic waves transmitted from the pair of transducers; An adder that adds a pair of received signals so that the second harmonic component of the vibration frequency has a mutually reinforcing phase in the received beam formed by the received signal of the oscillator Sound wave imaging device. 12. An ultrasonic imaging apparatus, wherein ultrasonic waves are transmitted to a subject and the second harmonic component of the echo is used, a scanning means for three-dimensionally scanning the inside of the subject with an ultrasonic beam, and an echo. An ultrasonic imaging apparatus comprising: a displacement calculating unit that obtains a displacement of a point of interest in a subject from a received signal; and a tracking unit that tracks a region of interest based on the displacement of the point of interest. 13. A first oscillator having a frequency band including a first frequency, and a second oscillator having a frequency band including a frequency twice the first frequency. Ultrasonic probe contact. 14. An ultrasonic contrast agent, wherein the particle size distribution of soluble microballoons is substantially within 1: 2.