JP5247958B2 - Ultrasonic diagnostic apparatus and ultrasonic echo signal processing method - Google Patents

Description

  The present invention relates to an ultrasonic diagnostic apparatus and an ultrasonic wave that control the removal of a fundamental wave component by a plurality of transmission / reception and independent signal processing for each received signal, and visualize a nonlinear component derived from a tissue or a contrast medium included in the received signal The present invention relates to an echo signal processing method.

  An ultrasonic diagnostic apparatus can obtain a tomographic image of a soft tissue in a living body non-invasively from the body surface by an ultrasonic pulse reflection method, such as an X-ray diagnostic apparatus, an X-ray CT apparatus, an MRI diagnostic apparatus, a nuclear medicine diagnostic apparatus, etc. Compared to other diagnostic apparatuses, it has features such as small size, low cost, real-time display, high safety without exposure to X-rays, and blood flow imaging. Because of this convenience, it is now widely used in the heart, abdomen, urology, and gynecology.

  In this ultrasonic image diagnostic apparatus, there are various imaging methods. For example, an imaging technique called a contrast echo method is to enhance an ultrasonic scattering echo by administering an ultrasonic contrast agent composed of microbubbles or the like into a blood vessel of a subject. There are a method of using the effect of enhancing reflection by bubbles and a method of using harmonics generated by the non-linear behavior of microbubbles. In addition, for example, an imaging technique called a tissue harmonic method is a method that utilizes nonlinear 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 nonlinear behavior of microbubbles or nonlinearity of radio waves in a biological tissue of ultrasonic waves. In this method, for example, as shown in FIG. 6, a wave for the purpose of image acquisition (positive wave) and a negative wave that is inverted from the positive wave and symmetric with the positive wave are applied to one scanning line. The fundamental wave component is canceled by adding the reflected waves obtained and transmitted as a fundamental wave, and a harmonic signal is extracted.

  In reality, however, there is an asymmetry between the positive and negative waves. When the reception echo signals obtained by the asymmetric positive and negative waves are added, the fundamental wave component cannot be canceled appropriately, and therefore the harmonic component cannot be extracted properly.

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

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

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

  As shown in FIG. 9, when the non-symmetrical positive and negative echo signals are added, as shown in the spectrum waveform B in FIGS. 9 and 7, the fundamental wave component that could not be canceled in the addition process Remains. The remaining fundamental wave component can be removed by filtering or the like in the fundamental wave band, but for the fundamental wave component existing in the harmonic region, the harmonic component is also removed at the same time. Cannot be removed.

  Also, in radiography for extracting harmonic components, since the high frequency is greatly affected by the frequency-dependent attenuation of the living body, the signal strength of the echo is lower than that of the fundamental wave, and a signal sufficient for imaging may not be obtained. In particular, when photographing a deep part of a living body, when photographing a patient with a large attenuation due to fat or the like, the signal intensity is weak and it is difficult to visualize the image.

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

Problems to be solved by the invention

  The present invention has been made in view of the above circumstances, and by making the best use of the characteristics of the phase inversion method, the harmonic component can be appropriately extracted and the fundamental component can be selectively extracted. An object of the present invention is to provide an ultrasonic diagnostic apparatus and an ultrasonic echo signal processing method.

Means for solving the problem

  In order to achieve the above object, the present invention takes the following measures.

The invention described in claim 1 includes a transmitting means for transmitting a first ultrasonic pulse and a second ultrasonic pulse having a substantially reversed polarity of the first ultrasonic pulse to the subject; Receiving means for receiving a first echo signal corresponding to the first ultrasonic pulse and a second echo signal corresponding to the second ultrasonic pulse from a specimen; gain adjusting means; and filter means. The first echo signal waveform or the second echo signal waveform is subjected to gain adjustment using a predetermined gain value and filter processing using a predetermined filter coefficient on at least one of the waveforms of the first echo signal and the second echo signal. Waveform adjusting means for increasing the symmetry between the waveform of the first echo signal and the waveform of the second echo signal; and adding the first echo signal and the second echo signal output from the waveform adjusting means. Do And at a transmit ultrasonic diagnostic apparatus characterized by comprising extraction means for extracting the harmonics generated by the ultrasonic wave.
The invention described in claim 6 includes a step of transmitting a first ultrasonic pulse to the subject, and a step of receiving a first echo signal corresponding to the first ultrasonic pulse from the subject. , A step of transmitting a second ultrasonic pulse substantially reversed in polarity of the first ultrasonic pulse to the subject, and a step of receiving a second echo signal corresponding to the second ultrasonic pulse. And applying a gain adjustment with a predetermined gain value and a filtering process with a predetermined filter coefficient to at least one of the waveform of the first echo signal or the waveform of the second echo signal, Increasing the symmetry between the waveform of the first echo signal and the waveform of the second echo signal, and the first echo signal and the second echo signal after the gain adjustment and filtering. By adding the bets, an ultrasonic echo signal processing method characterized by comprising the steps of extracting the harmonics generated from the transmission ultrasonic wave secondarily.

  According to such a configuration, it is possible to realize an ultrasonic diagnostic apparatus and an ultrasonic echo signal processing method capable of appropriately imaging a harmonic component by making full use of the characteristics of the phase inversion method. .

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, components having substantially the same function and configuration are denoted by the same reference numerals, and redundant description will be given 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 configuration diagram of the ultrasonic diagnostic apparatus 10.

  In FIG. 1, the 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 includes an array transducer arranged one-dimensionally or two-dimensionally. The ultrasonic probe 11 transmits an ultrasonic pulse into the living body according to a predetermined sequence. The ultrasonic pulse transmitted from the probe 11 into the living body propagates in the living body and generates various harmonic components due to the non-linearity of the living tissue. Further, in the case of contrast echo, a plurality of harmonic components are generated due to the nonlinearity of the ultrasound contrast agent in addition to the nonlinearity of the biological tissue. The fundamental wave and its harmonic component are backscattered by the boundary of the acoustic impedance of the body tissue, the minute scatterer, and the 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, control related to ultrasonic transmission / reception, control related to ultrasonic image display, and the like. The apparatus main body 12 includes a pulsar / preamplifier unit 15, a reception delay circuit 16, a synthesis unit 17, a detection unit 18, a display unit 19, a host CPU 20, and a waveform adjustment information storage memory 21. Hereinafter, each component will be described.

  The pulser / preamplifier unit 15 measures the drive timing of the vibration element of the probe 11 based on a control signal from the CPU 20, controls the pulse voltage applied to the plurality of vibration elements, and controls the ultrasonic beam transmitted from the probe 11. Controls direction, shape, and focusing. In particular, in the case of ultrasonic transmission by the phase inversion method, the pulsar / preamplifier unit 15 substantially reverses the polarity of a predetermined ultrasonic wave (positive wave) and the positive wave based on a control signal from the CPU 20. The vibrating element of the probe 11 is driven so that a fundamental wave composed of a symmetrized wave (negative wave) (for example, by inverting the waveform of the positive wave) is transmitted to one scanning line.

  Further, the pulsar / preamplifier unit 15 receives an echo signal based on a positive wave (hereinafter referred to as a positive echo signal) and an echo signal based on a negative wave (hereinafter referred to as a negative echo signal) for each channel. Amplified and output to the reception delay circuit 16 after A / D conversion.

  The reception delay circuit 16 performs beam forming at the time of reception and controls the direction and focusing of the beam. The reception delay circuit 16 may be composed of a plurality of circuit sets in order to form a plurality of beams and perform parallel simultaneous reception. The signal is AD-converted either before or after beam formation, 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, which will be described later, on at least one of the positive electrode echo signal and the negative electrode echo signal based on a predetermined condition, and extracts a harmonic signal for each scanning line. The synthesizing unit 17 includes gain adjusting means and filter means, and details thereof will be described later.

  The detection unit 18 performs log signal amplification, envelope detection processing, and the like on the harmonic signal and the like input from the synthesis unit 17 to generate data in which the signal intensity is expressed by brightness.

  The display unit 19 scan-converts the generated image signal, converts it into a video signal after image processing, and displays it on the monitor 13. In addition, when a plurality of harmonic signals are generated by the combining unit 17, image signals are generated independently and displayed independently or combined by the display unit 19.

  The host CPU 20 is a control unit that performs overall control of signal processing executed in each component.

  The waveform adjustment condition storage memory 21 is a storage unit that stores a plurality of waveform adjustment conditions for each depth from the subject surface. Here, the waveform adjustment conditions include the gain value of the gain adjusting means of the synthesis unit 17 and the filter coefficient of the filter means (for example, the representative example count stored in advance, or the spectrum waveform of the signal input by the filter means, It means 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, for example, a predetermined waveform adjustment condition is automatically selected by the host CPU 20 based on information on the subject (patient). 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 that displays an ultrasonic image acquired by the ultrasonic diagnostic apparatus 10.

  The operation unit 14 is connected to the apparatus main body 12 and is an input device (mouse, trackball, etc.) for setting a region of interest (ROI) for incorporating various instructions, commands, and information from the operator into the apparatus main body 12. Mode switch, keyboard, etc.).

  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, but it is also possible to manually change the waveform adjustment condition by the interface 140. 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 is adjusted. The waveform adjustment conditions are changed and set so that the fundamental wave component corresponding to is extracted from the echo signal.

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

  FIGS. 2A and 2B are block diagrams illustrating configuration examples of the synthesis unit 17, respectively. The synthesis unit 17 shown in FIG. 2A includes two processing systems, a first processing system including a gain adjustment unit 171A and a filter 172A, and a second processing system including a gain adjustment unit 171B and a filter 172B. And an adder 173. 2B includes a single processing system including a gain adjustment unit 171 and a filter 172, and an addition unit 173. The synthesis unit 17 illustrated in FIG.

  The gain adjustment unit 171, the gain adjustment unit 171 </ b> A, and the gain adjustment unit 171 </ b> B are circuits that perform gain adjustment on the input echo signals. Each gain adjustment unit performs gain adjustment based on the waveform adjustment condition selected from the memory 21 or the waveform adjustment condition changed by the interface 140. By the gain adjustment, the echo signal is selected only for the intensity necessary for extracting the harmonic component.

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

  The ultrasonic diagnostic apparatus 10 is configured to perform waveform adjustment after A / D conversion. However, in the case of a configuration in which spectrum adjustment or the like is performed on an analog signal before A / D conversion, the filter 172A is used. A real number filter, an equalizer, or the like can be used as the filter 172B.

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

  Next, a spectrum waveform adjustment process executed by the synthesis unit 17 having the above configuration will be described. The spectrum waveform adjustment processing is processing for 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 synthesis 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, which are input to the gain adjustment unit 171A and the gain adjustment unit 171B, respectively. Is done. The gain adjusting unit 171A and the filter 172A or the gain adjusting unit 171B and the filter 172B adjust the waveform of each echo signal according to preset waveform adjustment conditions (gain value, filter coefficient). The waveform adjustment may be performed on both the positive echo signal and the negative echo signal, or may be configured such that the other waveform is adjusted based on one waveform.

  In the synthesis unit 17 shown in FIG. 2B, 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 the gain adjustment unit 171. , And input to the filter 172. The gain adjusting unit 171 and the filter 172 adjust the waveform of each echo signal according to a preset gain value and filter coefficient.

  According to this waveform adjustment process, the fundamental wave component can be selectively acquired from the echo signal acquired by the phase inversion method by variously operating the waveform adjustment conditions. That is, when the waveform adjustment condition is set so that the spectrum waveform of the positive electrode echo signal and the spectrum waveform of the negative electrode echo signal are symmetric, the fundamental wave component can be removed by the addition processing in the addition unit 173. This is because the symmetrization can cancel out the fundamental wave component of the positive electrode echo signal and the fundamental wave component of the negative electrode echo signal with high accuracy (see FIG. 4, details of which will be described later). On the other hand, when the waveform adjustment condition is 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 (so as to increase the asymmetry), the fundamental wave is obtained by the addition process in the adder 173. Ingredients can be removed. This is because the asymmetry can extract part or all of the fundamental wave component of the positive echo signal or the fundamental wave component of the negative echo signal (see FIG. 5, details of which will be described later).

  Therefore, the waveform adjustment performed by the synthesis unit 17 includes symmetrization of the positive and negative echo signals, asymmetry of the positive and negative echo signals, or a combination thereof. These details will be clarified by examples described later.

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

Example 1
In the first embodiment, when ultrasonic image acquisition is performed by the phase inversion method, the received positive-polarity echo signal and the negative-polarity echo signal are symmetrized by the spectrum waveform adjustment function of the ultrasonic diagnostic apparatus 10 to be symmetrized. In this example, the fundamental component is removed with high accuracy and the harmonic component is extracted by adding the positive and negative echo signals.

  FIG. 3 is a flowchart showing a processing procedure of ultrasonic image collection by the phase inversion method. FIG. 4 is a conceptual diagram for explaining the spectrum waveform adjustment processing executed in the synthesis unit 17.

In FIG. 3, first, a positive wave is transmitted with a strength that destroys the contrast agent with respect to one scanning line, a positive echo signal based on the positive wave is received, and predetermined processing such as amplification and A / D conversion is performed. (Step S1)
Subsequently, a negative wave (see FIG. 6) obtained by inverting the waveform of the positive wave is transmitted into the subject, a negative echo signal based on the negative wave is received, and predetermined processing such as amplification and A / D conversion is performed. (Step S2).

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

The positive echo signal is combined with the negative echo signal with a delay of one rate .

  Note that, in the symmetrization of 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 the positive echo signal. Further, the configuration may be such that both the negative electrode echo signal and the negative electrode echo signal are adjusted and symmetrized.

  According to such a configuration, since the addition processing is performed after symmetrizing the positive electrode echo signal and the negative electrode echo signal, the fundamental component can be sufficiently removed and the harmonic component can be extracted. Therefore, the characteristics of the phase inversion method can be utilized to the maximum, and in particular, the artifact reduction effect by removing the fundamental wave component can be maximized. As a result, it is possible to improve the quality of the diagnostic image and contribute to the improvement of the diagnostic technique.

(Example 2)
The first embodiment has a configuration in which the fundamental wave signal is removed by symmetrizing the positive electrode echo signal and the negative electrode echo signal. In contrast, the second embodiment has a configuration in which the received positive echo signal and the negative echo signal are asymmetrically (disrupted in response) by the spectrum waveform adjustment function, and then the fundamental wave component is left by adding. This is an example. The fundamental wave component obtained in this way can be used to compensate for a harmonic echo signal from a deep part or an extremely short distance part with insufficient sensitivity. Note that the contents shown in this embodiment are particularly beneficial in, for example, tissue harmonic imaging.

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

  The synthesizing unit 17 performs asymmetry between the spectrum waveform of the positive echo signal and the spectrum waveform of the negative echo signal (step S3).

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

  In the subsequent image generation process, image generation is performed based on the fundamental wave component and the harmonic component (step S4).

  In general, since the harmonic component is a high frequency and greatly receives the frequency dependent attenuation of the living body, its sensitivity is low. In particular, when diagnosing the deep part of a living body or when diagnosing a patient with a lot of fat or the like, the attenuation is significant, and it is difficult to visualize an ultrasonic echo signal. Further, since harmonics are generated due to the nonlinear behavior of the contrast agent and the propagation of ultrasonic waves in the living tissue, harmonic components are not sufficiently generated at a very close distance from the subject surface.

  However, according to the configuration described above, since the addition processing is performed after the positive and negative echo signals are asymmetrical, the fundamental wave component can be left. The fundamental wave component obtained in this way can be used to compensate for a harmonic echo signal from a deep part or a very close range where sensitivity is insufficient. Therefore, it is possible to easily extract a harmonic echo signal sufficient for imaging from the deep part of the living body without intentionally shifting to the fundamental wave mode, and as a result, it is possible to contribute to improvement of the diagnostic technique.

(Example 3)
Generally, when the depth from the subject surface is low, a sufficient harmonic component can be obtained. On the other hand, when the depth is high, there are many cases where the harmonic components cannot be sufficiently extracted. Therefore, in the third embodiment, the synthesis unit 17 adjusts the waveform of the echo signal in accordance with the depth from the subject surface so that the residual degree of the fundamental wave for compensating 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 ultrasonic image collection by the phase inversion method is the processing content in step S3. In order to avoid duplication of explanation, only the processing contents 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 electrode echo signal and the negative electrode echo signal based on the waveform adjustment condition (step S3).

  That is, when the positive electrode echo signal and the negative electrode echo signal are input, the synthesis unit 17 determines the gain value corresponding to the depth of each echo signal based on the waveform adjustment condition stored in the waveform adjustment condition storage memory 21. The spectrum waveform is adjusted by the filter coefficient. The waveform adjustment conditions are set in advance so that the symmetry of the spectrum waveform of the positive echo signal and the spectrum waveform of the negative echo signal changes according to the depth from the subject surface, and the fundamental wave component is extracted according to the depth. Has been. For example, in a region from the subject surface to a depth of 5 mm and a region from a depth of 10 cm to 15 cm, the harmonic component is not sufficient, so that the waveform adjustment condition can extract both the fundamental wave component and the harmonic component from a depth of 5 mm. Since the harmonic components can be collected sufficiently up to a depth of 10 cm, the harmonic adjustment component can be used to extract only the harmonic component. It is. In this way, when the waveform adjustment condition is controlled according to the depth, biometric information (fundamental wave component and harmonic component) suitable for diagnosis can be extracted for each depth by the addition processing of the addition unit 173.

  Note that the waveform adjustment conditions (gain value, filter coefficient) can be arbitrarily changed, and in the symmetrization and asymmetry of the spectrum waveform of the positive echo signal and the spectrum waveform of the negative echo signal, either or The point which may be the structure which adjusts both waveforms is the same as that of each above-mentioned Example. In particular, regarding the change of the waveform adjustment conditions (gain value, filter coefficient), the depth at which the fundamental wave component starts to be extracted can be easily changed by the interface shown in FIG.

  In the subsequent image generation processing, image generation is performed based on the fundamental wave component and the harmonic component, so that an ultrasonic image in which the harmonic echo component is insufficient, for example, a signal from the deep part of the living body, is supplemented by the band of the fundamental wave. It is generated (step S4).

  According to the configuration described above, the waveform of the echo signal can be adjusted according to the depth from the subject surface. In particular, the sensitivity of the harmonic echo signal in the deep part of the subject varies depending on the subject, but appropriate waveform adjustment conditions can be easily set by automatic setting based on patient information or manual setting using 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, those skilled in the art can come up with various changes and modifications within the scope of the idea of the present invention. It is understood that it belongs to the scope of the present invention.

  Further, the embodiments may be combined as appropriate as possible, and in that case, the combined effect can be obtained. Furthermore, the above 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 constituent requirements are deleted from all the constituent requirements shown in the embodiment, the problem described in the column of the problem to be solved by the invention can be solved, and the effect described in the column of the effect of the invention If at least one of the following is obtained, a configuration in which this configuration requirement is deleted can be extracted as an invention.

Effect of the invention

  As described above, according to the present invention, an ultrasonic diagnostic apparatus and an ultrasonic echo that can appropriately extract a harmonic component and selectively extract a fundamental component by making the best use of the characteristics of the phase inversion method. A signal processing method can be realized.

  FIG. 1 shows a block configuration diagram of the ultrasonic diagnostic apparatus 10.   FIGS. 2A and 2B are block diagrams illustrating configuration examples of the synthesis unit 17, respectively. FIG. 2C shows the user interface 140.   FIG. 3 is a flowchart showing a processing procedure of ultrasonic image collection by the phase inversion method.   FIG. 4 is a conceptual diagram for explaining the spectrum waveform adjustment processing executed in the synthesis unit 17.   FIG. 5 is a conceptual diagram for explaining the spectrum waveform adjustment processing executed in the synthesis unit 17.   FIG. 6 is a diagram showing waveforms of positive and negative waves transmitted in the phase inversion method.   FIG. 7 is a diagram showing a spectrum waveform A of the positive echo signal and a spectrum waveform B obtained by adding the positive echo signal and the negative echo signal.   FIG. 8 is a diagram showing on-axis sound pressures of the fundamental wave component and the harmonic component shown in FIG.   FIG. 9 is a diagram schematically showing the spectrum waveform of the positive electrode echo signal, the spectrum waveform of the negative electrode echo signal, and the residual of the fundamental wave.   FIG. 10 is a diagram schematically showing, for example, the spectrum waveforms of the positive and negative echo signals from the deep part of the living body, and the harmonic components extracted by adding both echo signals.

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

Claims (6)

Transmitting means for transmitting a first ultrasonic pulse and a second ultrasonic pulse substantially inverted in polarity of the first ultrasonic pulse to the subject;
Receiving means for receiving a first echo signal corresponding to the first ultrasonic pulse and a second echo signal corresponding to the second ultrasonic pulse from the subject;
Gain adjustment means and filter means, and gain adjustment by a predetermined gain value and a predetermined filter coefficient for at least one of the waveform of the first echo signal and the waveform of the second echo signal Waveform adjusting means for increasing the symmetry between the waveform of the first echo signal and the waveform of the second echo signal by performing the filtering process according to
Extraction means for extracting harmonics generated by transmission ultrasonic waves by adding the first echo signal and the second echo signal output from the waveform adjustment means;
An ultrasonic diagnostic apparatus comprising:
The ultrasonic diagnostic apparatus according to claim 1, wherein the transmission unit transmits the first ultrasonic pulse and the second ultrasonic pulse a plurality of times to one scanning line .
The user interface for a user to change the ratio of the transmission ultrasonic wave extracted by the extraction means by changing at least one of the gain value or the filter coefficient is provided. The ultrasonic diagnostic apparatus as described.
The ultrasonic diagnostic apparatus according to claim 1, wherein the waveform adjusting unit adjusts a spectrum waveform of the first echo signal or the second echo signal.
5. The ultrasonic diagnostic apparatus according to claim 1, wherein the filter coefficient is a ratio between a spectrum waveform of an echo signal input by the filter means and a spectrum waveform of an echo signal output by the filter means. .
Transmitting a first ultrasonic pulse to a subject;
Receiving a first echo signal corresponding to the first ultrasonic pulse from the subject;
Transmitting a second ultrasonic pulse substantially inverted in polarity of the first ultrasonic pulse to the subject;
Receiving a second echo signal corresponding to the second ultrasonic pulse;
By performing gain adjustment with a predetermined gain value and filter processing with a predetermined filter coefficient on at least one of the waveform of the first echo signal and the waveform of the second echo signal, Increasing the symmetry between the waveform of the echo signal and the waveform of the second echo signal;
Adding the first echo signal after the gain adjustment and filtering and the second echo signal to extract a second harmonic generated from the transmission ultrasonic wave; and
An ultrasonic echo signal processing method comprising:

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