JP2002369817A - Ultrasonic diagnostic device and ultrasonic echo signal processing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ultrasonic diagnostic device and an ultrasonic echo signal processing method appropriately extracting harmonic components and selectively extracting fundamental wave components by utilizing the feature of a phase inversion method to the maximum. SOLUTION: When ultrasonic images are gathered by the phase inversion method, by a spectrum waveform adjusting function, received positive electrode echo signals and negative electrode echo signals are made symmetrical and the positive electrode echo signals and the negative electrode echo signals which are made symmetrical are added together. Thus, the fundamental wave components are highly accurately eliminated and the harmonic components are extracted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention controls the removal of a fundamental wave component by a plurality of transmission / reception and independent signal processing for each reception signal, and visualizes a non-linear component derived from tissue or a contrast agent contained in the reception signal. The present invention relates to an ultrasonic diagnostic apparatus and an ultrasonic echo signal processing method.

[0002]

2. Description of the Related Art An ultrasonic diagnostic apparatus is capable of non-invasively obtaining a tomographic image of soft tissue in a living body from a body surface by an ultrasonic pulse reflection method, and comprises an X-ray diagnostic apparatus, an X-ray CT apparatus, an MRI diagnostic apparatus, Compared with other diagnostic devices such as a nuclear medicine diagnostic device, it has features such as small size, low cost, real-time display, high safety without exposure to X-rays, and blood flow imaging. Due to such convenience, it is now widely used in the heart, abdomen, urology, obstetrics and gynecology, and the like.

[0003] There are various imaging methods in this ultrasonic image diagnostic apparatus. For example, an imaging method called a contrast echo method is to administer an ultrasonic contrast agent composed of microbubbles (microbubbles) or the like into a blood vessel of a subject,
Ultrasonic scattering echo is enhanced, and there are a method using an enhancement effect of reflection by microbubbles and a method using harmonics generated by nonlinear behavior of microbubbles. An imaging method called, for example, a tissue harmonic method is a method that utilizes nonlinearity of propagation of ultrasonic waves in a living tissue.

In recent years, a phase inversion method has been developed as a technique for extracting a harmonic component (harmonic component) generated by the nonlinear behavior of microbubbles or the nonlinearity of an ultrasonic wave in a living tissue. In this method, for example, as shown in FIG. 6, a wave for the purpose of image acquisition (positive wave) and a negative wave obtained by inverting the waveform of the positive wave and symmetrical with the positive wave are applied to one scanning line. Then, a fundamental wave component is canceled out by adding the reflected waves thus obtained, and a harmonic signal is extracted.

However, in reality, there is asymmetry between the positive and negative waves. When the received echo signals obtained by the asymmetric positive and negative waves are added, the fundamental wave component cannot be appropriately canceled out, and therefore, the harmonic component cannot be properly extracted.

FIG. 7 shows a spectrum waveform A of an echo signal based on the positive wave shown in FIG. 6 (hereinafter referred to as a positive echo signal), and an echo signal based on the positive echo signal and the negative wave shown in FIG. Hereinafter, it is referred to as a negative echo signal.)
FIG. 6 is a diagram showing a spectrum waveform B obtained by adding

FIG. 8 is a diagram showing the on-axis sound pressure of the fundamental wave component and the harmonic component shown in FIG.

FIG. 9 is a diagram schematically showing a spectrum waveform of a positive echo signal, a spectrum waveform of a negative echo signal, and a residual fundamental wave.

As shown in FIG. 9, when a non-symmetrical positive echo signal and a negative echo signal are added, as shown in spectrum waveforms B in FIGS. 9 and 7, they cannot be canceled in the adding process. The fundamental wave component remains.
This residual fundamental wave component can be removed by filtering or the like in the band of the fundamental wave. However, as for the fundamental wave component existing in the harmonic region, the harmonic component is also removed at the same time. Cannot be removed.

In radiography for extracting a harmonic component, since the high frequency is greatly affected by the frequency-dependent attenuation of the living body, the signal intensity of the echo is lower than that of the fundamental wave, and a signal sufficient for imaging cannot be obtained. There is. In particular, when imaging a deep part of a living body, or when imaging a patient whose attenuation is large due to fat or the like, the signal intensity is weak and imaging is difficult.

FIG. 10 is a diagram schematically showing, for example, a spectrum waveform of a positive echo signal and a negative echo signal from a deep part of a living body, and a harmonic component extracted by adding both echo signals. As shown in FIG.
The harmonic component extracted from the echo signal in the deep part of the living body is lower than the noise level, and is not sufficient for imaging.

[0012]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above circumstances, and utilizes the characteristics of the phase inversion method to the maximum extent to properly extract the harmonic component and remove the fundamental wave component. It is an object of the present invention to provide an ultrasonic diagnostic apparatus and an ultrasonic echo signal processing method capable of selectively extracting.

[0013]

The present invention employs the following means to achieve the above object.

According to a first aspect of the present invention, a first ultrasonic pulse and a polarity of the first ultrasonic pulse are substantially inverted with respect to one scanning plane of a subject to which a contrast agent has been administered. The second
Transmitting means for transmitting a fundamental wave pulse composed of an ultrasonic pulse and a first echo signal corresponding to the first ultrasonic pulse and a second echo signal corresponding to the second ultrasonic pulse from the subject. Receiving means for receiving the second echo signal;
Gain adjustment means and filter means, for at least one of the waveform of the first echo signal and the waveform of the second echo signal, gain adjustment by a predetermined gain value and a predetermined filter coefficient Waveform adjusting means for increasing the symmetry between the waveform of the first echo signal and the waveform of the second echo signal by applying the filter processing of the first echo signal and the first echo signal input from the waveform adjusting means. An ultrasonic diagnostic apparatus, comprising: an extraction unit configured to extract a second harmonic generated from the fundamental wave pulse by adding the second echo signal.

According to a second aspect of the present invention, the first ultrasonic pulse and the polarity of the first ultrasonic pulse are substantially inverted with respect to one scan plane of the subject to which the contrast agent has been administered. The second
Transmitting means for transmitting a fundamental wave pulse composed of an ultrasonic pulse and a first echo signal corresponding to the first ultrasonic pulse and a second echo signal corresponding to the second ultrasonic pulse from the subject. Receiving means for receiving the second echo signal;
Gain adjustment means and filter means, for at least one of the waveform of the first echo signal and the waveform of the second echo signal, gain adjustment by a predetermined gain value and a predetermined filter coefficient Waveform adjusting means for increasing the asymmetry between the waveform of the first echo signal and the waveform of the second echo signal by applying the filter processing of the first echo signal and the first echo signal input from the waveform adjusting means. By adding the second echo signal,
An ultrasonic diagnostic apparatus comprising extraction means for extracting at least one of the fundamental wave pulse and at least one of a second harmonic generated from the fundamental wave pulse.

According to a third aspect of the present invention, the first ultrasonic pulse and the polarity of the first ultrasonic pulse are substantially inverted with respect to one scanning plane of the subject to which the contrast agent has been administered. The second
Transmitting means for transmitting a fundamental wave pulse composed of an ultrasonic pulse and a first echo signal corresponding to the first ultrasonic pulse and a second echo signal corresponding to the second ultrasonic pulse from the subject. Receiving means for receiving the second echo signal;
A gain adjusting unit and a filter unit, wherein at least one of the waveform of the first echo signal and the waveform of the second echo signal is at a depth from the surface of the subject within the subject. Waveform adjustment means for adjusting the waveform by performing gain adjustment by a predetermined gain value every time, and performing filter processing by a predetermined filter coefficient for each depth from the surface of the subject in the subject. By adding the first echo signal and the second echo signal input from the waveform adjusting means, a harmonic generated secondarily from the fundamental wave pulse and the surface of the subject in the subject An ultrasonic diagnostic apparatus comprising: extracting means for selectively extracting at least a part of the fundamental wave pulse in accordance with a depth from the ultrasonic wave.

According to a fourth aspect of the present invention, the first ultrasonic pulse and the polarity of the first ultrasonic pulse are substantially inverted with respect to one scan plane of the subject to which the contrast agent has been administered. The second
Transmitting a fundamental wave pulse composed of a first ultrasonic signal and a second echo pulse corresponding to the first ultrasonic pulse and the second ultrasonic pulse corresponding to the second ultrasonic pulse from the subject. Receiving an echo signal of
By performing gain adjustment using a predetermined gain value and filtering processing using a predetermined filter coefficient on at least one of the waveform of the first echo signal and the waveform of the second echo signal, the first waveform is obtained. Increasing the symmetry between the waveform of the second echo signal and the waveform of the second echo signal, and adding the first echo signal and the second echo signal after the gain adjustment and the filter processing. Extracting a second harmonic generated from the fundamental wave pulse.

According to a fifth aspect of the present invention, the first ultrasonic pulse and the polarity of the first ultrasonic pulse are substantially inverted with respect to one scanning plane of the subject to which the contrast agent has been administered. The second
Transmitting a fundamental wave pulse composed of a first ultrasonic signal and a second echo pulse corresponding to the first ultrasonic pulse and the second ultrasonic pulse corresponding to the second ultrasonic pulse from the subject. Receiving an echo signal of
By performing gain adjustment using a predetermined gain value and filtering processing using a predetermined filter coefficient on at least one of the waveform of the first echo signal and the waveform of the second echo signal, the first waveform is obtained. Increasing the symmetry between the waveform of the second echo signal and the waveform of the second echo signal, and adding the first echo signal and the second echo signal after the gain adjustment and the filter processing. Extracting at least one of the fundamental wave pulse and at least one of the secondarily generated harmonics from the fundamental wave pulse.

According to a sixth aspect of the present invention, a first ultrasonic pulse and a subject to which the first ultrasonic contrast agent has been administered are applied to one scan plane of the subject to which the contrast agent has been administered. Transmitting a fundamental wave pulse composed of a first ultrasonic pulse and a second ultrasonic pulse in which the polarity of the first ultrasonic pulse is substantially inverted to one scan surface of the sample; And a first echo signal corresponding to the first ultrasonic pulse from the subject and a second echo signal corresponding to the second ultrasonic pulse.
Receiving at least one of the waveform of the first echo signal and the waveform of the second echo signal for each depth from the surface of the subject in the subject. Adjusting the waveform by performing a gain adjustment with a predetermined gain value and a filtering process with a predetermined filter coefficient for each depth from the surface of the subject in the subject; and By adding the processed first echo signal and the second echo signal, at least one of the fundamental wave pulse and a harmonic that is generated secondary from the fundamental wave pulse is added. Extracting the ultrasonic echo signal.

According to such a configuration, an ultrasonic diagnostic apparatus and an ultrasonic echo signal processing method capable of appropriately imaging a harmonic component are realized by maximizing the characteristics of the phase inversion method. be able to.

[0021]

Embodiments of the present invention will be described below with reference to the drawings. In the following description, components having substantially the same functions and configurations are denoted by the same reference numerals, and repeated description will be made only when necessary.

First, a block configuration of the ultrasonic diagnostic apparatus 10 according to the first embodiment will be described with reference to FIG.

FIG. 1 shows a block diagram of an ultrasonic diagnostic apparatus 10.

Referring to FIG. 1, an ultrasonic diagnostic apparatus 10 includes an ultrasonic probe 11, an apparatus main body 12, a monitor 13, and an operation unit 14.

The ultrasonic probe 11 is connected to the apparatus main body 12 and comprises an array transducer arranged one-dimensionally or two-dimensionally. The ultrasonic probe 11 transmits an ultrasonic pulse into a living body according to a predetermined sequence. The ultrasonic pulse transmitted into the living body from the probe 11 is
While propagating in the living body, various harmonic components are generated due to the nonlinearity of the living tissue. In the case of a contrast echo, a plurality of harmonic components are generated due to the nonlinearity of the ultrasonic contrast agent in addition to the nonlinearity of the living tissue. The fundamental wave and its harmonic component are backscattered by the boundary of the acoustic impedance of the body tissue, a small scatterer, and an ultrasonic contrast agent, and received by the probe 11 as an ultrasonic echo signal.

The apparatus main body 12 performs processing on ultrasonic signals collected from the subject, controls on transmission and reception of ultrasonic waves, and controls on display of ultrasonic images. The device body 12
Pulsar / preamplifier unit 15, reception delay circuit 16,
Synthesis unit 17, detection unit 18, display unit 1
9, a host CPU 20, and a waveform adjustment information storage memory 21. Hereinafter, each component will be described.

The pulsar / preamplifier unit 15 has a CP
The drive timing of the vibrating element of the probe 11 is measured based on the control signal from the U20, the pulse voltage applied to the plurality of vibrating elements is controlled, and the direction, shape, and focusing of the ultrasonic beam transmitted from the probe 11 are controlled. I do. Particularly, in the case of ultrasonic transmission by the phase inversion method, the pulser / preamplifier unit 15 substantially reverses a predetermined ultrasonic wave (positive wave) and the positive wave and the polarity based on a control signal from the CPU 20. The vibrating element of the probe 11 is driven such that a fundamental wave composed of a symmetrical wave (a negative wave) (for example, by inverting the waveform of the positive wave) is transmitted to one scanning line.

The pulsar / preamplifier unit 15
Receives an echo signal based on a positive-polarity wave (hereinafter, referred to as a positive-polarity echo signal) and an echo signal based on a negative-polarity wave (hereinafter, referred to as a negative-polarity echo signal), amplifies each channel, and performs A / D conversion. The signal is output to the reception delay circuit 16 later.

The reception delay circuit 16 controls beam direction and convergence by performing beam forming at the time of reception. The reception delay circuit 16 may be composed of a plurality of circuit sets for forming a plurality of beams and performing parallel simultaneous reception. The signal is A / D converted before or after beam forming, and the received signal is sampled at a sampling frequency suitable for signal processing to become a digital signal.

The synthesizing unit 17 performs a waveform adjustment process described later on at least one of the positive echo signal and the negative echo signal based on a predetermined condition, and extracts a harmonic signal for each scanning line. The synthesis unit 17 is
It comprises a gain adjusting means and a filter means, the details of which will be described later.

The detection unit 18 performs logarithmic amplification of the echo signal, envelope detection processing, and the like on the harmonic signal and the like input from the synthesis unit 17 to generate data whose signal intensity is represented by brightness.

The display unit 19 scan-converts the generated image signal, converts the image signal into a video signal after image processing, and displays the video signal on the monitor 13. When a plurality of harmonic signals are generated by the synthesizing unit 17, the image signals are generated independently, and are displayed independently or synthesized by the display unit 19.

The host CPU 20 is a control section that controls the signal processing executed in each component.

The waveform adjustment condition storage memory 21 is a storage unit for storing a plurality of waveform adjustment conditions for each depth from the surface of the subject. Here, the waveform adjustment conditions include the gain value of the gain adjustment means of the synthesizing unit 17 and the filter coefficient of the filter means (for example, a representative example count stored in advance, or the spectrum waveform of a signal input to the filter means, (E.g., the ratio of the signal output from the filter means to the spectrum waveform). Among the plurality of waveform adjustment conditions stored in the waveform adjustment condition storage memory 21, a predetermined waveform adjustment condition is automatically selected by the host CPU 20 based on, for example, information on a subject (patient). Note that each waveform adjustment condition stored in the memory 21 can be changed by a predetermined input operation from the operation unit 14.

The monitor 13 is an output device for displaying an ultrasonic image acquired by the ultrasonic diagnostic apparatus 10.

The operation unit 14 is connected to the apparatus main body 12,
Various instructions, instructions, and information from the operator
Input device (mouse, trackball, mode changeover switch, keyboard, etc.) for setting a region of interest (ROI) and the like to capture the image.

The operation unit 14 has a user interface 140 shown in FIG. The interface is an adjustment lever for adjusting a waveform adjustment condition described later according to the depth. That is, normally, a predetermined waveform adjustment condition in the memory 21 is automatically selected and determined based on predetermined information.
It is also possible to manually change the waveform adjustment conditions. The adjustment lever shown in FIG. 2C is for adjusting the ratio of the fundamental wave component extracted from the received echo signal. For example, when the lever is moved by a predetermined amount in the fundamental wave direction, the predetermined amount The waveform adjustment condition is changed and set so that a fundamental wave component corresponding to the above is extracted from the echo signal.

Next, the configuration of the synthesizing unit 17 will be described.

FIGS. 2A and 2B are block diagrams showing examples of the configuration of the synthesizing unit 17, respectively. FIG.
The combining unit 17 shown in FIG.
A first processing system including A and a filter 172A, a second processing system including a gain adjustment unit 171B and a filter 172B, and an addition unit 173. The combining unit 17 illustrated in FIG. 2B includes a single processing system including a gain adjusting unit 171 and a filter 172, and an adding unit 173.

Gain adjuster 171, gain adjuster 171
A, a gain adjustment unit 171B is a circuit that adjusts the gain of each input echo signal. Each of the gain adjustment units includes a waveform adjustment condition selected from the memory 21;
Alternatively, gain adjustment is performed based on the waveform adjustment conditions changed by the interface 140. By the gain adjustment, the echo signal is selected to have only the intensity necessary for extracting the harmonic component.

The filter 172, the filter 172A, and the filter 172B are, for example, a spectrum adjusting means, a complex filter, and the like used in an ultrasonic diagnostic apparatus disclosed in Japanese Patent Application Laid-Open No. 9-173334. Each filter adjusts the input echo signal by a filter coefficient based on a waveform adjustment condition selected from the memory 21 or a waveform adjustment condition changed by the interface 140 to obtain a predetermined spectrum waveform. I do.

In the present ultrasonic diagnostic apparatus 10, the A / D
Although the configuration is such that the waveform adjustment is performed after the conversion, but the configuration is such that the spectrum adjustment or the like is performed on the analog signal before A / D conversion, the filters 172A and 172B
, A real number filter, an equalizer, or the like can be used.

The adder 173 extracts a harmonic component or a fundamental wave component by adding the input positive echo signal and negative echo signal.

Next, the synthesizing unit 17 having the above configuration
Will be described. The spectrum waveform adjustment process is a process of adjusting at least one of the spectrum waveform of the positive echo signal or the spectrum waveform of the negative echo signal collected by the phase inversion method.

For example, in the synthesizing unit 17 shown in FIG. 2A, the digital signal from the reception delay circuit 16 is classified into a positive echo signal and a negative echo signal, and the gain adjuster 171A and the gain adjuster 171 respectively. 171B. Gain adjuster 171A and filter 172
A or gain adjustment unit 171B and filter 172B
Adjusts the waveform of each echo signal according to preset waveform adjustment conditions (gain value, filter coefficient). In addition,
The waveform adjustment may be performed on both the positive echo signal and the negative echo signal, or may be adjusted based on one waveform to adjust the other waveform.

Further, the synthesizing unit 1 shown in FIG.
In 7, the digital signal from the reception delay circuit 16 is classified into a positive echo signal and a negative echo signal, and only one of the echo signals is input to the gain adjustment unit 171 and the filter 172. The gain adjuster 171 and the filter 172 adjust the waveform of each echo signal using a preset gain value and filter coefficient.

According to this waveform adjustment processing, the fundamental wave component can be selectively obtained from the echo signal obtained by the phase inversion method by variously operating the waveform adjustment conditions. That is, when the waveform adjustment conditions are set such that the spectrum waveform of the positive echo signal and the spectrum waveform of the negative echo signal are symmetric,
The fundamental wave component can be removed by the addition processing in the addition section 173. This is because, by the symmetry, the fundamental wave component of the positive echo signal and the fundamental wave component of the negative echo signal can be canceled with high accuracy (see FIG. 4, and details of the figure will be described later). On the other hand, if the waveform adjustment conditions are set so that the symmetry between the spectrum waveform of the positive echo signal and the spectrum waveform of the negative echo signal is broken (to increase the asymmetry), the addition processing in the addition unit 173 causes the fundamental wave The components can be removed. This is because a part or all of the fundamental wave component of the positive echo signal or the fundamental wave component of the negative echo signal can be extracted by the asymmetry (see FIG. 5; details of the drawing will be described later).

Accordingly, the waveform adjustment performed by the synthesizing unit 17 includes symmetry of the positive echo signal and the negative echo signal, asymmetry of the positive echo signal and the negative echo signal, or a combination thereof. These details will be clarified by examples described later.

Next, embodiments of the ultrasonic diagnostic apparatus 10 will be described.

(First Embodiment) In the first embodiment, when an ultrasonic image is collected by the phase inversion method, the received positive echo signal and negative echo signal are received by the spectrum waveform adjusting function of the ultrasonic diagnostic apparatus 10. This is an example in which the fundamental component is removed with high accuracy by extracting the harmonic component by adding the symmetrical positive echo signal and negative electrode echo signal.

FIG. 3 is a flow chart showing a procedure for acquiring an ultrasonic image by the phase inversion method. FIG. 4 is a conceptual diagram for explaining the spectrum waveform adjustment processing executed in the synthesizing unit 17.

In FIG. 3, first, a positive wave is transmitted to one scanning line according to the intensity at which a contrast agent is destroyed, a positive echo signal based on the positive wave is received, and a predetermined signal such as amplification and A / D conversion is performed. (Step S1) Then, a negative wave (see FIG. 6) obtained by inverting the waveform of the positive wave is transmitted into the subject, and a negative echo signal based on the negative wave is received. A predetermined process such as / D conversion is performed (step S2).

Subsequently, in the synthesizing unit 17, the positive echo signal and the negative echo signal are symmetrical (step S3). That is, as shown in FIG. 4, for example, when a positive echo signal and a negative echo signal in which the symmetry of the spectrum waveform is broken are input, the synthesizing unit 17 makes, for example, the waveform of the negative echo signal symmetric. The waveform of the fundamental wave of the positive echo signal is adjusted by the gain adjuster 171A and the filter 172A. The adjusted spectrum waveform of the positive echo signal and the spectrum waveform of the negative echo signal are symmetric as shown in FIG. 4, and by adding (synthesizing) these, the fundamental component is canceled to extract the harmonic component. be able to.

The positive echo signal is delayed by one rate and combined with the negative echo signal. This is done (* Please supplement the reason.) Subsequently, logarithmic amplification, envelope detection processing, etc. are performed on the added echo signal to generate an image signal (step S4), and the image signal is scan-converted. After the image processing, the image signal is converted into a video signal and displayed on the monitor 13 (step S5).

In the symmetry between the positive echo signal and the negative echo signal in step S3, the positive echo signal is adjusted based on the negative echo signal. However, the negative echo signal is adjusted based on the positive echo signal, or A configuration may be adopted in which both the positive echo signal and the negative echo signal are adjusted to be symmetric.

According to such a configuration, since the addition processing is performed after the positive echo signal and the negative echo signal are symmetrical, the fundamental component can be sufficiently removed and the harmonic component can be extracted. Therefore, the characteristics of the phase inversion method can be maximized, and in particular, the effect of reducing the artifact by removing the fundamental wave component can be maximized. As a result, the quality of the diagnostic image can be improved, which can contribute to the improvement of the diagnostic technology.

(Embodiment 2) The embodiment 1 has a configuration in which the fundamental wave signal is removed by making the positive echo signal and the negative echo signal symmetrical. On the other hand, in the second embodiment, the received positive echo signal and the negative echo signal are asymmetrical by the spectrum waveform adjustment function (causing loss of handling),
This is an example in which a fundamental wave component is left by adding the components. The fundamental wave component obtained in this way is
It can be used to compensate for harmonic echo signals from deep or very close areas where sensitivity is lacking. The contents shown in the present embodiment are particularly useful in, for example, tissue harmonic imaging.

The difference between the second embodiment and the first embodiment in the processing procedure of ultrasonic image acquisition by the phase inversion method is the processing content in step S3 in FIG.
In order to avoid duplication of description, only the processing in step S3 will be described with reference to FIGS.

The synthesizing unit 17 makes the spectrum waveform of the positive echo signal and that of the negative echo signal asymmetric (step S3).

FIG. 5 is a conceptual diagram for explaining the spectrum waveform adjustment processing executed in the synthesizing unit 17. As shown in FIG. 5, when the positive echo signal and the negative echo signal are input, the synthesizing unit 17 causes the gain adjusting unit 171B and the filter 172B to output the negative echo signal so as to be asymmetric with the waveform of the positive echo signal. Adjust the waveform of the fundamental wave. The adjusted fundamental wave waveform (spectrum) is asymmetric as shown in FIG. 5, and by adding these, a fundamental wave component and a harmonic component can be extracted.

In the subsequent image generation processing, an image is generated based on the fundamental wave component and the harmonic component (step S4).

Generally, the harmonic component is a high frequency and is greatly affected by the frequency-dependent attenuation of a living body.
Its sensitivity is low. In particular, when diagnosing a deep part of a living body or diagnosing a patient having a lot of fat or the like, attenuation is remarkable, and it is difficult to visualize an ultrasonic echo signal. Further, since harmonics are generated due to nonlinear behavior of a contrast agent or propagation of ultrasonic waves in living tissue, a harmonic component is not sufficiently generated at a very short distance from the surface of the subject.

However, according to the above-described configuration, the addition processing is performed after the positive echo signal and the negative echo signal are asymmetric, so that the fundamental wave component can be left. The fundamental wave component obtained in this manner can be used to supplement a harmonic echo signal from a deep part or a very short distance area where sensitivity is insufficient. Therefore, it is possible to easily extract a harmonic echo signal sufficient for imaging from a deep part of a living body or the like without intentionally transitioning to the fundamental wave mode, thereby contributing to an improvement in diagnostic technology.

(Embodiment 3) In general, when the depth from the surface of the subject is low, a sufficient harmonic component can be obtained. On the other hand, when the depth is high, the harmonic component cannot be sufficiently extracted in many cases. Therefore, in the third embodiment, the waveform of the echo signal is adjusted in the synthesizing unit 17 according to the depth from the subject surface so that the residual degree of the fundamental wave for complementing the harmonic echo signal increases as the depth increases. It is an example.

The difference between the third embodiment and each embodiment in the processing procedure of the ultrasonic image acquisition by the phase inversion method is the processing content in step S3. In order to avoid repetition, only the processing in step S3 will be described with reference to FIG.

The synthesizing unit 17 performs gain adjustment and filter processing on at least one of the positive echo signal and the negative echo signal based on the waveform adjustment conditions (step S3).

That is, when the positive echo signal and the negative echo signal are input, the synthesizing unit 17 determines the depth of each echo signal based on the waveform adjustment conditions stored in the waveform adjustment condition storage memory 21. The spectrum waveform is adjusted by the gain value and the filter coefficient. The waveform adjustment condition is set in advance so that the symmetry between the spectrum waveform of the positive echo signal and the spectrum waveform of the negative echo signal is changed according to the depth from the subject surface, and the fundamental wave component is extracted according to the depth. Have been. For example, in a region up to a depth of 5 mm from the surface of the subject and in a region from a depth of 10 cm to 15 cm, the harmonic component is not sufficient, so that both the fundamental component and the harmonic component can be extracted from the waveform adjustment condition, and 10cm depth
Until the harmonic components can be sufficiently collected, the waveform adjustment conditions for extracting only the harmonic components, and in the region with a depth of 15 cm or more, almost no harmonic components can be extracted.
And so on. When the waveform adjustment condition is controlled according to the depth in this way, the addition processing of the addition unit 173 can extract biological information (basic wave component and harmonic component) suitable for diagnosis for each depth.

It should be noted that the waveform adjustment conditions (gain value, filter coefficient) can be arbitrarily changed, and any of the symmetry and the asymmetry between the spectrum waveform of the positive echo signal and the spectrum waveform of the negative echo signal can be changed. The point that one or both of the waveforms may be adjusted is the same as in the above-described embodiments. In particular, for changing the waveform adjustment conditions (gain value, filter coefficient), see FIG.
With the interface shown in FIG. 3C, the depth at which the fundamental wave component starts to be extracted can be easily changed.

In the subsequent image generation processing, an image is generated based on the fundamental wave component and the harmonic component. Therefore, a signal that is insufficient for the harmonic echo component, for example, a signal from a deep part in the living body is supplemented by the band of the fundamental wave. A sound image is generated (Step S4).

According to the configuration described above, it is possible to adjust the waveform of the echo signal according to the depth from the surface of the subject. In particular, the sensitivity of the harmonic echo signal in the deep part inside the subject varies depending on the subject, but appropriate waveform adjustment conditions can be easily set by automatic setting based on patient information or the like or manual setting by an interface. Therefore, the harmonic effect can be used to the maximum, and as a result, the quality of the diagnostic image can be improved and the diagnostic technique can be improved.

Although the present invention has been described based on the embodiments, various changes and modifications may be made by those skilled in the art within the scope of the present invention. It is understood that examples also fall within the scope of the present invention.

Further, the embodiments may be combined as appropriate as much as possible, in which case the combined effects can be obtained. Furthermore, the embodiments include inventions at various stages, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent elements. For example, even if some components are deleted from all the components shown in the embodiment, the problem described in the column of the problem to be solved by the invention can be solved, and the effects described in the column of the effect of the invention can be solved. When at least one of the above is obtained, a configuration from which this configuration requirement is deleted can be extracted as an invention.

[0073]

As described above, according to the present invention, by utilizing the characteristics of the phase inversion method to the maximum, it is possible to appropriately extract the harmonic component and selectively extract the fundamental wave component. An apparatus and an ultrasonic echo signal processing method can be realized.

[Brief description of the drawings]

FIG. 1 shows a block diagram of an ultrasonic diagnostic apparatus 10. FIG.

FIGS. 2A and 2B are block diagrams each showing a configuration example of a synthesizing unit 17. FIGS. FIG. 2 (c)
FIG. 4 is a diagram showing a user interface 140.

FIG. 3 is a flowchart illustrating a processing procedure of ultrasonic image acquisition by a phase inversion method.

FIG. 4 is a conceptual diagram for explaining a spectrum waveform adjustment process performed in a synthesizing unit 17;

FIG. 5 is a conceptual diagram for explaining a spectrum waveform adjustment process performed in a synthesizing unit 17;

FIG. 6 is a diagram showing waveforms of a positive wave and a negative wave transmitted in the phase inversion method.

FIG. 7 is a spectrum waveform A of a positive electrode echo signal.
FIG. 6 is a diagram showing a spectrum waveform B obtained by adding the positive echo signal and the negative echo signal.

FIG. 8 is a diagram illustrating the on-axis sound pressure of the fundamental wave component and the harmonic component illustrated in FIG. 7;

FIG. 9 is a diagram schematically showing a spectrum waveform of a positive echo signal, a spectrum waveform of a negative echo signal, and residual fundamental waves.

FIG. 10 is a diagram schematically illustrating, for example, a spectrum waveform of a positive echo signal and a negative echo signal from a deep part of a living body, and a harmonic component extracted by adding both echo signals.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Ultrasonic diagnostic apparatus 11 ... Ultrasonic probe 12 ... Device main body 13 ... Monitor 14 ... Operation part 15 ... Preamplifier unit 16 ... Reception delay circuit 17 ... Synthesis unit 18 ... Detection unit 19 ... Display unit 20 ... Host CPU 21 ... Waveform Adjustment condition storage memory 140 User interface 171A Gain adjuster 171B Gain adjuster 171 Gain adjuster 172A Filter 172B Filter 172 Filter 173 Adder

 ──────────────────────────────────────────────────続 き Continued on the front page F term (Reference) 4C301 AA02 BB23 DD13 EE04 EE06 EE11 EE20 GB03 GB09 HH01 HH02 HH24 HH33 HH37 HH38 HH46 HH48 HH52 JB03 JB06 JB11 JB13 JB29 JB32 JB35 JB42 JB50 KK30

Claims (10)

[Claims] A transmitting means for transmitting, to a subject, a first ultrasonic pulse and a second ultrasonic pulse obtained by substantially reversing the polarity of the first ultrasonic pulse; The first corresponding to one ultrasonic pulse
Receiving means for receiving the second echo signal corresponding to the second echo signal and the second ultrasonic pulse, gain adjusting means and filter means, and the waveform of the first echo signal or the second By performing gain adjustment with a predetermined gain value and filtering with a predetermined filter coefficient on at least one of the waveforms of the echo signal, the waveform of the first echo signal and the waveform of the second echo signal are obtained. And a waveform adjusting means for increasing the symmetry of the first and the second echo signals output from the waveform adjusting means, thereby extracting harmonics generated by the transmitted ultrasonic waves. An ultrasonic diagnostic apparatus, comprising: an extracting unit that performs the following. 2. A transmitting means for transmitting a first ultrasonic pulse and a second ultrasonic pulse in which the polarity of the first ultrasonic pulse is substantially inverted, and wherein the first ultrasonic pulse is transmitted from the subject to the first ultrasonic pulse. The first corresponding to the sound pulse
Receiving means for receiving a second echo signal corresponding to the second echo signal and the second ultrasonic pulse, gain adjusting means and filter means, wherein the waveform of the first echo signal or the second By performing gain adjustment using a predetermined gain value and filtering processing using a predetermined filter coefficient on at least one of the waveforms of the echo signal, the waveform of the first echo signal and the waveform of the second echo signal are obtained. Waveform adjusting means for increasing the asymmetry between the first and second echo signals, and the first echo signal and the second echo signal input from the waveform adjusting means are added, so that at least a part of the transmission ultrasonic waves and the transmission ultrasonic waves are added. Extracting means for extracting at least one of harmonics generated secondarily from sound waves. An ultrasonic diagnostic apparatus comprising: 3. A transmitting means for transmitting a first ultrasonic pulse and a second ultrasonic pulse in which the polarity of the first ultrasonic pulse is substantially inverted, and wherein the first ultrasonic pulse is transmitted from the subject to the first ultrasonic pulse. The first corresponding to the sound pulse
Receiving means for receiving a second echo signal corresponding to the second echo signal and the second ultrasonic pulse, gain adjusting means and filter means, wherein the waveform of the first echo signal or the second For at least one of the waveforms of the echo signal, gain adjustment by a predetermined gain value for each depth from the subject surface in the subject, and the depth from the subject surface in the subject. By performing a filtering process using a predetermined filter coefficient each time, a waveform adjusting unit for adjusting the waveform, and the first echo signal and the second echo signal output from the waveform adjusting unit are added. By this, the harmonics that are generated secondarily from the transmitted ultrasonic waves and at least a part of the transmitted ultrasonic waves selectively depending on the depth from the surface of the subject within the subject are extracted. Ultrasonic diagnostic apparatus characterized by comprising extracting means for, the. 4. An ultrasonic diagnostic apparatus according to claim 1, wherein said transmitting means transmits said fundamental wave pulse a plurality of times to said one scanning plane. 5. The apparatus according to claim 1, further comprising a user interface for allowing a user to change a ratio of transmission ultrasonic waves extracted by said extraction means by changing at least one of said gain value and said filter coefficient. The ultrasonic diagnostic apparatus according to claim 1. 6. The ultrasonic diagnostic apparatus according to claim 1, wherein said waveform adjusting means adjusts a spectrum waveform of said first echo signal or said second echo signal. 7. The apparatus according to claim 1, wherein said filter coefficient is a ratio between a spectrum waveform of an echo signal input to said filter means and a spectrum waveform of an echo signal output from said filter means. Ultrasonic diagnostic equipment. 8. A step of transmitting a first ultrasonic pulse to a subject, and a first step corresponding to the first ultrasonic pulse from the subject.
Receiving an echo signal of the first ultrasonic pulse; transmitting a second ultrasonic pulse obtained by substantially inverting the polarity of the first ultrasonic pulse to the subject; and transmitting a second ultrasonic pulse corresponding to the second ultrasonic pulse. Receiving at least one of the waveform of the first echo signal and the waveform of the second echo signal, using a gain adjustment with a predetermined gain value and a predetermined filter coefficient. Increasing the symmetry between the waveform of the first echo signal and the waveform of the second echo signal by performing filter processing; and performing the gain adjustment and the filter processing on the first echo signal and the second echo signal. Extracting the secondarily generated harmonics from the transmitted ultrasonic wave by adding the two echo signals to each other. Method. 9. A method for transmitting a first ultrasonic pulse to a subject, the method comprising: transmitting a first ultrasonic pulse from the subject to a first ultrasonic pulse corresponding to the first ultrasonic pulse;
Receiving an echo signal of the first ultrasonic pulse; transmitting a second ultrasonic pulse obtained by substantially inverting the polarity of the first ultrasonic pulse to the subject; and transmitting a second ultrasonic pulse corresponding to the second ultrasonic pulse. Receiving at least one of the waveform of the first echo signal and the waveform of the second echo signal, using a gain adjustment with a predetermined gain value and a predetermined filter coefficient. Increasing the symmetry between the waveform of the first echo signal and the waveform of the second echo signal by performing a filtering process; and performing the gain adjustment and the filtering process on the first echo signal and the second echo signal. By adding at least one of the two echo signals, a step of extracting at least one of at least a part of the transmission ultrasonic wave and a harmonic generated secondarily from the fundamental pulse is performed. An ultrasonic echo signal processing method, comprising: 10. A step of transmitting a first ultrasonic pulse to a subject, and a first step corresponding to the first ultrasonic pulse from the subject.
Receiving an echo signal of the first ultrasonic pulse; transmitting a second ultrasonic pulse obtained by substantially inverting the polarity of the first ultrasonic pulse to the subject; and transmitting a second ultrasonic pulse corresponding to the second ultrasonic pulse. Receiving at least one of the waveform of the first echo signal and the waveform of the second echo signal from the surface of the subject in the subject. Adjusting the waveform by performing a gain adjustment with a predetermined gain value every time, and performing a filtering process with a predetermined filter coefficient for each depth from the surface of the subject in the subject. By adding the first echo signal and the second echo signal after the filter processing, the secondary echo is generated from at least a part of the transmission ultrasonic wave and the fundamental pulse. Extracting at least one of the following harmonics: