JP2007236740A - Ultrasonic diagnostic apparatus and control program thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ultrasonic diagnostic apparatus capable of obtaining a diagnostic image with constantly high image quality regardless of the difference in the subject or the region. <P>SOLUTION: The ultrasonic diagnostic apparatus comprises an adding part 23 to extract a fundamental wave component and a harmonic component from echo signals; a signal generating part 37 to generate a first image signal SA based on the fundamental wave component and a second image signal SC based on the harmonic component; a gain adjusting part 31 to calculate the signal gain GC to fix the intensity of the second image signal constant in the direction of depth of the subject and the noise gain GN to fix the intensity of white noise constant in the direction of depth of the subject; a weighting factor computing part 32 to compute the weighting factors WA and WC based on the signal gain and the noise gain; and a composing part 29 to generate a third image signal SD on which the diagnostic image is reflected by multiplying the first image signal by the weighting factor WA, multiplying the second image signal by the weighting factor WC and adding the results of the multiplication. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an ultrasonic diagnostic apparatus that extracts a harmonic component derived from nonlinear propagation of ultrasonic waves in a living tissue and visualizes a tomographic structure of the living tissue.

  In conventional ultrasonic diagnosis, a technique of imaging a tomographic structure of a living tissue using a fundamental wave component included in an echo signal from the living tissue is often used. However, the technique using the fundamental wave component of the echo signal often causes artifacts (virtual images), resulting in a problem that the image quality of the diagnostic image is degraded.

  Therefore, in recent years, so-called tissue nonlinear acoustic imaging (Tissue Harmonic Imaging) has been used to visualize the tomographic structure of living tissue by utilizing the nonlinearity of ultrasonic wave propagation speed in living tissue. It was.

  Tissue nonlinear acoustic imaging is a technique that uses only the second harmonic of the harmonic component contained in the echo signal from the living tissue to visualize the tomographic structure of the living tissue, and has reduced artifacts. There is a feature that a good high-contrast image can be obtained.

  Thereby, in the current ultrasonic diagnosis, a diagnostic image with higher image quality than before can be obtained, and the diagnostic ability in ultrasonic diagnosis has been improved.

  As a method for extracting only the harmonic component, a so-called pulse subtraction (PS) method is known (see, for example, Non-Patent Document 1). In this pulse subtraction method, two types of ultrasonic waves whose phases are inverted are transmitted to each of a plurality of scanning lines at a low sound pressure, and two echo signals corresponding to these two types are received. Then, by adding these echo signals and removing the fundamental wave component, only the harmonic component from the living tissue is extracted.

  In tissue nonlinear acoustic imaging, a tomographic structure of a living tissue may be visualized by using only a difference sound component of a harmonic component included in an echo signal from the living tissue (see, for example, Patent Document 1). ).

  Although it is not a technique for imaging the tomographic structure of living tissue, a technique for imaging blood flow dynamics using the fact that the contrast agent bubble used in ultrasound diagnosis is extremely delicate is also used. It is like that.

  As a method of extracting only the echo component from the contrast agent bubble, a so-called rate subtraction (RS) method is known (see, for example, Patent Document 2). In this rate subtraction method, the same ultrasonic wave is transmitted twice with high sound pressure to each of a plurality of scanning lines, and two echo signals corresponding to these two transmissions are received. Then, the echo component from the disappeared contrast agent bubble is extracted by subtracting these two echo signals and removing the overlapping component.

  That is, since the contrast agent bubbles used in ultrasonic diagnosis are very delicate, many of them are instantaneously destroyed when irradiated with ultrasonic waves. Therefore, the echo signal obtained by the second ultrasonic transmission is smaller than the echo signal obtained by the first ultrasonic transmission. However, the echo signal from the living tissue does not change greatly. Therefore, the echo signal from the lost contrast agent bubble is reflected in the difference signal obtained from these two echo signals. Thus, if the rate subtraction method is used, the echo signal from the living tissue is removed, and only the blood flow dynamics can be visualized.

  In the conventional ultrasonic diagnosis, so-called white noise, in which internal noise specific to the ultrasonic diagnostic apparatus is displayed in white on the diagnostic image, may occur. When white noise occurs, there is a problem in that the signal-to-noise ratio (S / N ratio) decreases, and the image quality of the diagnostic image decreases.

In recent years, therefore, a technique has been proposed in which the gain is automatically optimized based on the echo signal and white noise from the living tissue to improve the image quality of the diagnostic image (see, for example, Patent Document 3).
Ariru Kaoru, Kamakura Tomio, "Nonlinear Propagation of Ultrasonic Pulses", Science Technique, US89-23, P53 JP 2004-298620 A JP-A-8-336527 US Pat. No. 6,398,733

  However, tissue nonlinear acoustic imaging may lack sensitivity in the deep part of an ultrasound image as compared with a method of imaging a tomographic structure of a biological tissue from a fundamental wave component included in an echo signal. This is because when the ultrasonic wave propagates through the living tissue, so-called frequency-dependent attenuation occurs according to the distance and frequency.

  Therefore, in recent years, the applicant of the present application has proposed a new technique for synthesizing the fundamental wave component and the harmonic component to make the sensitivity of the ultrasonic image uniform over the entire image. However, although the attenuation factor of the frequency-dependent attenuation differs for each subject or region, this method uses a predetermined weighting factor. For this reason, the weighting coefficient does not match the subject or the site, and a diagnostic image with high image quality may not be obtained.

  The present invention has been made in view of the above circumstances, and the object of the present invention is that there are few artifacts, there is no lack of sensitivity even in the deep part, and it is always high regardless of the difference in the subject or part. An object of the present invention is to provide an ultrasonic diagnostic apparatus capable of obtaining a diagnostic image of image quality and a control program thereof.

  The ultrasonic diagnostic apparatus and its control program according to the present invention are configured as follows.

(1) In an ultrasound diagnostic apparatus that scans a subject with ultrasound and obtains a diagnostic image of the subject, transmits an ultrasound to the subject and receives an echo signal from the subject; Based on the first component, a transmission / reception unit for receiving noise, a component extraction unit for extracting the first and second components from the echo signal, and generating the first signal, Based on the signal generation means for generating a second signal, and based on the first signal, a first gain for making the intensity of the first signal constant in the depth direction of the subject, Gain calculation means for calculating a second gain for making the noise intensity constant in the depth direction of the subject based on the noise, and the first signal based on the first and second gains A first weighting factor and the first A weighting factor calculating means for calculating a second weighting factor relating to the signal of the first, a first weighting factor applied to the first signal, a second weighting factor applied to the second signal, and adding these Signal synthesizing means for generating a third signal, and display means for displaying the diagnostic image based on the third signal.

(2) In the ultrasonic diagnostic apparatus described in (1), the transmission / reception unit transmits two types of ultrasonic waves whose phases are inverted to each of a plurality of scanning lines, and The first and second echo signals corresponding to the ultrasonic waves are received, and the component extraction means extracts the first component by adding the first and second echo signals for each scanning line, and The second component is extracted by subtracting the first and second echo signals for each scanning line.

(3) In the ultrasonic diagnostic apparatus described in (1), the transmission / reception unit transmits two types of ultrasonic waves whose phases are inverted to each of a plurality of scanning lines, and the two types of ultrasonic waves are transmitted for each scanning line. The first and second echo signals corresponding to the ultrasonic waves are received, and the component extraction means extracts the first component by adding the first and second echo signals for each scanning line, and The first echo signal or the second echo signal is extracted as the second component.

(4) In the ultrasonic diagnostic apparatus described in (1), the component extraction unit applies a first filter to the echo signal to extract the first component and outputs a second to the echo signal. The second component is extracted by applying a filter.

(5) In the ultrasonic diagnostic apparatus described in (1), the gain calculating means is configured to make the intensity of the third signal constant in the depth direction of the subject based on the third signal. 3 is calculated, and an optimum gain setting for displaying the diagnostic image is set based on the second and third gains.

(6) The ultrasonic diagnostic apparatus described in (1) further includes an instruction unit that causes the weighting factor calculating unit to calculate the first and second weighting factors.

(7) In the ultrasonic diagnostic apparatus described in (1), based on the first and second gains, transmission frequency, reception frequency, reception filter characteristics, transmission sound pressure, display depth, dynamic range, post-process At least one setting condition of a curve, transmission sound pressure, display width, display frequency, transmission beam number, reception beam number, simultaneous reception beam number, image processing coefficient, transmission waveform, and transmission wave number is designated.

(8) In the ultrasonic diagnostic apparatus described in (7), the setting condition is determined in advance.

(9) In the ultrasonic diagnostic apparatus described in (1), the display unit displays the diagnostic image as a 3D video or a 4D video.

(10) In the ultrasonic diagnostic apparatus described in (1), the first component is a harmonic component of the echo signal, and the second component is a fundamental wave component of the echo signal.

(11) In the ultrasonic diagnostic apparatus described in (1), the first component is a harmonic component of the echo signal, and the second component is the echo signal itself.

(12) In the control program for the ultrasound diagnostic apparatus, the echo is transmitted to the subject to receive an echo signal from the subject, and to the ultrasound diagnostic apparatus including transmission / reception means for receiving noise. A signal extracting function for extracting the first and second components from the signal and a signal for generating the first signal based on the first component and generating the second signal based on the second component Based on the generation means and the first signal, a first gain for making the intensity of the first signal constant in the depth direction of the subject is calculated, and the intensity of the noise is calculated based on the noise. Based on the first and second gains, a first weighting factor for the first component, and a second weighting function for calculating a second gain that is constant in the depth direction of the subject No. on the ingredients of A weighting factor calculating function for calculating the weighting factor of the first component, a first weighting factor applied to the first component, a second weighting factor multiplied to the second component, and adding these to a third signal And a display function for displaying the diagnostic image based on the third signal.

  According to the present invention, there are few artifacts, the sensitivity is not insufficient even in the deep part, and a diagnostic image with high image quality is always obtained regardless of the difference in the subject or the part.

Hereinafter, the first to third embodiments will be described with reference to the drawings.
(First embodiment)
First, the first embodiment will be described with reference to FIGS.
FIG. 1 is a block diagram of an ultrasonic diagnostic apparatus according to the first embodiment of the present invention.
As shown in FIG. 1, the ultrasonic diagnostic apparatus according to this embodiment includes an ultrasonic probe 10 and an apparatus main body 20.

  The ultrasonic probe 10 is detachably connected to the apparatus main body 20, and a so-called 2D array transducer is provided at the tip thereof. Therefore, the ultrasonic probe 10 according to the present embodiment can transmit and receive three-dimensional ultrasonic waves.

  The apparatus main body 20 includes a transmission / reception unit (transmission / reception unit) 21, a first memory 22, an addition unit (component extraction unit) 23, a detection unit 24, a filter unit 25, an envelope unit 26, a log compression unit 27, and a second memory 28. , A synthesis unit (signal synthesis unit) 29, an image processing unit 30, a gain adjustment unit (gain calculation unit) 31, a weighting factor calculation unit (weighting factor calculation unit) 32, an image memory 33, a digital scan converter 34, a monitor (display unit) ) 35 and an instruction switch (instruction means) 36.

  The transmission / reception unit 21 includes a transmission unit for transmitting ultrasonic waves and a reception unit for receiving echo signals from living tissue. The first memory 22 stores the echo signal from the transmission / reception unit 21. When an echo signal is input from the transmission / reception unit 21, the addition unit 23 adds the echo signal and another echo signal stored in the first memory 22.

  The detector 24 detects the echo signal from the adder 23 at a frequency corresponding to the echo signal. The filter unit 25 applies a frequency filter corresponding to the detection process to the echo signal from the detection unit 24 and extracts only a necessary frequency component.

  The envelope unit 26 applies an envelope to the echo signal from the filter unit 25. The log compressing unit 27 performs log compression on the echo signal from the envelope unit 26 to generate an image signal.

  That is, the detection unit 24, the filter unit 25, the envelope unit 26, and the log compression unit 27 constitute a signal generation unit (signal generation unit) 37 that processes an echo signal from the addition unit 23 to generate an image signal. Yes.

  The second memory 28 stores the image signal from the log compression unit 27. The synthesizer 29 multiplies the image signal stored in the second memory 28 and the image signal from the log compressor 27 by the weighting factor calculated by the weighting factor calculator 32 and adds them. To do.

  The image processing unit 30 performs various image processing on the image signal from the combining unit 29. The gain adjusting unit 31 adjusts the gain based on the image signal from the image processing unit 30. The weighting factor calculation unit 32 calculates a weighting factor based on the gain from the gain adjustment unit 31.

  The image memory 33 sequentially stores the image signal from the image processing unit 30. The digital scan converter 34 converts a scanning line signal sequence obtained by scanning into a scanning line signal sequence of a general video format represented by a television or the like. The monitor 35 displays the image signal from the digital scan converter 34 as a three-dimensional (3D) diagnostic image or a four-dimensional (4D) diagnostic image. The instruction switch 36 causes the weighting coefficient calculation unit 32 to start calculating the weighting coefficient based on the operation by the operator.

(Diagnosis image generation)
In the scanning sequence in the present embodiment, two ultrasonic waves whose phases are inverted for each scanning line, that is, first and second ultrasonic waves are continuously transmitted. The first and second ultrasonic waves are reflected by a discontinuous surface of the acoustic impedance in the subject, and two echo signals whose phases are reversed, that is, first and second ultrasonic signals corresponding to the first and second ultrasonic waves, The second echo signals EA and EB are received by the transmission / reception unit 21.

  The first and second echo signals EA and EB include both the fundamental wave component and the harmonic component, but the harmonic wave component is very small compared to the fundamental wave component, so that the fundamental wave component is reflected. Is considered to be.

  The first echo signal (second component) EA received earlier is stored in the first memory 22, passes through the adder 23, and proceeds to the detector 24. Then, when the second echo signal EB received later arrives at the adder 23, the first echo signal EA stored in the first memory 22 and the second echo signal arrived at the adder 23. EB is added to generate a third echo signal (first component) EC.

  By the way, as described above, the phases of the first and second echo signals EA and EB are inverted. Therefore, when the first and second echo signals EA and EB are added, the fundamental wave components included in the first and second echo signals EA and EB are canceled, and only the harmonic component is doubled. . As a result, the third echo signal EC reflects the harmonic component from the living tissue.

  When the third echo signal EC is generated, the first echo signal EA has already advanced ahead of the adding unit 23. The preceding first echo signal EA and the third echo signal EC following the first echo signal EA are respectively detected by the detection unit 24, the filter unit 25, and the envelope unit 26. The processing and the log compression processing in the log compression unit 27 are sequentially performed to obtain the first and second image signals SA and SC. Since the first and second image signals SA and SC are generated based on the first and third echo signals EA and EC, the fundamental wave component and the harmonic component are reflected, respectively.

  The first image signal SA output from the log compression unit 27 is temporarily stored in the second memory 28. Then, when the second image signal SC output from the Log compression unit 27 with a delay arrives at the combining unit 29, the first image signal SA stored in the second memory 28 is multiplied by the weight coefficient WA, A weighting factor WC is applied to the second image signal SC that has reached the combining unit 29, and these are added. As a result, a third image signal SD composed of the first image signal SA and the second image signal SC is generated.

The third image signal SD is obtained by the first image signal SA and the second image signal SC.
SD = SA × WA + SC × WC
It is expressed. The weighting factors WA and WC are calculated by the weighting factor calculation unit 32. The calculation method will be described in detail later.

  The third image signal SD is sequentially stored in the image memory 33 after being subjected to various image processing by the image processing unit 30. Then, the third image signal SD accumulated in the image memory 33 is scan-converted by the digital scan converter 34 and displayed on the monitor 35 one after another as a diagnostic image. The monitor 35 can display the internal structure of the subject in a moving image by selecting a display method.

  Incidentally, as described above, the first image signal SA reflects the fundamental wave component, and the second image signal SC reflects the harmonic component. Therefore, the third image signal SD is composed of a fundamental wave component and a harmonic component.

  The contribution ratio of the fundamental wave component and the harmonic component in the third image signal SD is determined by the magnitude relationship between the weighting factors WA and WC. For example, when the weighting factor WA is large and the weighting factor WC is small, the third image signal SD is a reflection of the fundamental wave component, that is, a blend of more fundamental wave components. Further, when the weighting factor WA is small and the weighting factor WC is large, the third image signal SD is a signal in which the harmonic component is more reflected, that is, a signal in which the fundamental wave component is less blended.

FIG. 2 is a graph of the weighting factors WA and WC in the same embodiment.
As shown in FIG. 2, the weighting coefficient WA is small at the shallow portion and increases as it goes to the deep portion. On the other hand, the weighting coefficient WC is large at the shallow part and decreases as it goes to the deep part. In the intermediate portion, the weight coefficients WA and WC are close to each other. Therefore, in the third image signal SD, the harmonic component is more reflected in the shallow portion and the fundamental wave component is more reflected in the deep portion.

(Weight coefficient WA, WC setting sequence)
FIG. 3 is a flowchart relating to a diagnostic image generation process when the setting sequence of the weighting factors WA and WC is operating in the embodiment.
As shown in FIG. 3, when the instruction switch 36 is pressed (step S1), a sequence for setting the weighting factors WA and WC is started. In the setting sequence of the weighting factors WA and WC, first, empty transmission for one frame is performed by the transmission / reception unit 21 (step S2). Note that idle reception refers to performing only reception without performing transmission of ultrasonic waves. Therefore, when one frame of empty reception is performed by the transmission / reception unit 21, a noise signal for one frame is generated due to internal noise inherent in the ultrasonic probe 10 and the apparatus main body 20. Incidentally, the noise signal from the ultrasonic probe 10 or the apparatus main body 20 is sometimes displayed as white noise on the monitor 35 and is therefore sometimes called white noise.

  The generated noise signal is processed in the same manner as the echo signal, and then sent to the gain adjusting unit 31 to calculate a noise gain GN that makes the intensity of the noise signal constant in the depth direction of the subject. (Step S3).

  Next, the transmission / reception unit 21 transmits / receives one frame to / from the subject (step S4). Again, the transmission / reception performed follows the scan sequence described above. Therefore, when the transmission / reception unit 21 transmits / receives one frame to / from the subject, the second image signal SC corresponding to one frame reflecting the harmonic component is generated.

  The generated second image signal SC is sent to the gain adjusting unit 31, and a signal gain GC is set such that the intensity of the second image signal SC, that is, the intensity of the harmonic component becomes constant in the depth direction of the subject. Calculated (step S5).

  The calculated noise gain GN and signal gain GC are sent to the weight coefficient calculation unit 32, and based on these noise gain GN and signal gain GC, the weight coefficient WA related to the first image signal SA and the second image signal. The WC related to the SC is calculated (step S6). This completes the sequence of setting the weighting factors WA and WC.

  When the setting sequence of the weighting factors WA and WC is completed, the calculated weighting factors WA and WC are sent to the combining unit 29 as described above and applied to the first and second image signals SA and SC, respectively. As a result, a third image signal SD composed of the fundamental wave component and the harmonic component is generated (step S7). The generated third image signal SD is successively displayed on the monitor 35 (step S8).

FIG. 4 is a graph of the noise gain GN and the signal gain GC in the same embodiment.
As shown in FIG. 4, the noise gain GN and the signal gain GC intersect at a certain depth, and in a region deeper than the intersection point P, the noise gain GN is lower than the signal gain GC. This indicates that the intensity of the noise signal in the region deeper than the intersection point P is larger than the intensity of the second image signal SC.

  Therefore, when the gain of the diagnostic image is set to the signal gain GC, in a region deeper than the intersection point P, the harmonic component is disturbed by white noise and is not clearly displayed. On the contrary, in an area shallower than the intersection point P, the harmonic component is clearly displayed without being disturbed by white noise.

  Therefore, in the present embodiment, the intersection point P between the noise gain GN and the signal gain GC is used for setting the weighting factors WA and WC. That is, in the region deeper than the intersection point P, the weighting factor WA is set high, and in the region shallower than the intersection point P, the weighting factor WA is set low. Thereby, the blend ratio of the fundamental wave component is high in a region deeper than the intersection point P, and the blend ratio of the fundamental wave component is low in a region shallower than the intersection point P.

  However, when the weighting coefficient WA increases rapidly with the intersection point P as a boundary, a discontinuous portion is formed in the generated diagnostic image. Therefore, in practice, the blend ratio of the fundamental wave component is set so as to gradually change from a region shallower than the intersection point P to a deep region.

  Note that the blend ratio of the fundamental wave component in this embodiment increases linearly in the depth region from 60% to 240% of the intersection point P, 0% in the depth region up to 60% of the intersection point P, It becomes 100% in a region deeper than 240% of the intersection point P. With such a blend ratio, it has been confirmed that a diagnostic image with high image quality is generated from a shallow part to a deep part. However, the numerical values of these blend ratios are only examples, and other numerical values may be used.

(Results of experiment by phantom)
FIG. 5 is a diagnostic image of a phantom having an attenuation rate of 0.7 [dB / MHz · cm] in the embodiment, and (a) is a case where the setting sequence of the weighting factors WA and WC is not activated. b) shows a case where the setting sequence of the weighting factors WA and WC is operating. A spherical target T is embedded in the deep part of the phantom.

  As shown in FIG. 5A, when the setting sequence of the weighting factors WA and WC is not activated, the target T is not drawn. This indicates that the sensitivity in the deep part of the diagnostic image is low.

  However, as shown in FIG. 5B, when the setting sequence of the weighting factors WA and WC is operating, the target T is depicted in the deep part of the diagnostic image. This indicates that the sensitivity in the deep part of the diagnostic image is increased by the operation of the setting sequence of the weighting factors WA and WC.

  FIG. 6 is a diagnostic image of a phantom having an attenuation rate of 0.3 [dB / MHz · cm] in the embodiment, and (a) is a case where the setting sequence of the weighting factors WA and WC is not activated. b) shows a case where the setting sequence of the weighting factors WA and WC is operating. A spherical target T is embedded in the deep part of the phantom.

  As shown in FIG. 6A, when the setting sequence of the weighting factors WA and WC is not operating, the target T is depicted in the deep part of the diagnostic image. This indicates that the sensitivity in the deep part of the diagnostic image is sufficiently high.

  As shown in FIG. 6B, even when the setting sequence of the weighting factors WA and WC is operating, the target T is depicted in the deep part of the diagnostic image. This indicates that even if the setting sequence of the weighting factors WA and WC is activated, the sensitivity remains high if there is sufficient sensitivity from the beginning in the deep part of the diagnostic image.

  From the above experiment, it is proved that the ultrasonic diagnostic apparatus according to the present embodiment sets the optimum weighting factors WA and WC for each attenuation rate even if there is a difference in attenuation rate for each subject or part. It was.

(Operation by this embodiment)
In the present embodiment, the third image signal SD is obtained by applying a weight coefficient WA to the first image signal SA reflecting the fundamental wave component, and applying a weight coefficient WC to the second image signal SC reflecting the harmonic component. Multiply them and add them. The weight coefficient WA of the first image signal SA is set to be large at the shallow portion of the subject and small at the deep portion, and the weight coefficient WC of the second image signal SC is set at the shallow portion of the subject. It is set to be small and large in the deep part.

  As a result, the diagnostic image generated based on the third image signal SD reflects the harmonic component more in the shallow part of the subject and more reflects the fundamental wave component in the deep part. Therefore, the sensitivity of the ultrasonic image is not insufficient even in the deep part of the subject, and sufficient sensitivity for diagnosis can be obtained over the entire image.

  Moreover, the weighting factors WA and WC are automatically based on the noise gain GN generated from the noise signal reflecting white noise and the signal gain GC generated from the second image signal SC reflecting the harmonic component. It is calculated by.

  Therefore, even if there is a difference in the attenuation rate of the frequency-dependent attenuation for each subject, or even if there is a difference in the attenuation rate of the frequency-dependent attenuation for each region of the subject, the optimum weight coefficient WA, Since the WC is reliably set, a diagnostic image with high image quality can be obtained without being affected by the difference in the subject or the part.

  In addition, since the shallow part of the subject is imaged based on the harmonic component, the occurrence of artifacts is drastically suppressed as compared to the case where imaging is performed using only the fundamental wave component.

  As described above, according to the ultrasonic diagnostic apparatus of the present embodiment, there are few artifacts, sufficient sensitivity can be obtained even in the deep part, and a diagnostic image with high image quality can always be obtained regardless of the difference in the subject or part. It is done.

  Further, in the present embodiment, the apparatus main body 20 includes an instruction switch 36 that starts a sequence for setting the weighting factors WA and WC. Therefore, since the image quality of the diagnostic image can be switched very easily, the work load on the operator is reduced.

  In the present embodiment, the addition process by the adder 23 is used to obtain the first echo signal EA reflecting the fundamental wave component and the third echo signal EC reflecting the harmonic component. Yes. However, the present invention is not limited to this. That is, if the first echo signal EA reflecting the fundamental wave component and the third echo signal EC reflecting the harmonic component are acquired from the echo signal received by the transmission / reception unit 21, the technique is completely different. For example, instead of the adder 23, there are a first filter that passes only the fundamental wave component and a second filter that passes only the harmonic component from the echo signal received by the transmitter / receiver 21. It may be used.

(Second Embodiment)
Next, a second embodiment will be described with reference to FIG.
FIG. 7 is a flowchart relating to a diagnostic image generation process when the setting sequence of the weighting factors WA and WC is operating in the second embodiment of the present invention.
As shown in FIG. 7, the diagnostic image generation process in the present embodiment includes steps S9 to S13, as indicated by a two-dot chain line, between steps S7 and S8 of the display sequence in the first embodiment. Have been added.

  That is, when the third image signal SD is generated (step S7), empty transmission for one frame is performed by the transmission / reception unit 21 (step S9), and a noise signal for one frame reflecting white noise is generated. The Then, the generated noise signal is sent to the gain adjusting unit 31, and the noise gain GN is calculated (step S10).

  Next, the transmission / reception unit 21 transmits / receives one frame to / from the subject (step S11), and a third image signal SD for one frame is generated. Then, the generated third image signal SD is sent to the gain adjusting unit 31, and a signal gain (third gain) GD is calculated (step S12).

  In the first embodiment, the signal gain GC is calculated based on the second image signal SC in which the harmonic component is reflected. In the present embodiment, the signal gain GC is composed of a harmonic component and a fundamental wave component. Note that the signal gain GD is calculated based on the third image signal SD.

  When the noise gain GN and the signal gain GD are calculated, the optimum display gain G for displaying a diagnostic image is set based on the noise gain GN and the signal gain GD (step S13).

  That is, in the diagnostic image generation process in the present embodiment, the display gain G optimum for displaying the diagnostic image is set by the gain adjustment unit 31 before the third image signal SD is displayed on the monitor 35. In other words, in this embodiment, the display gain G is optimized after the fundamental component is blended with the harmonic component. Therefore, the diagnostic image displayed on the monitor 35 is very clear and does not depict white noise.

(Third embodiment)
Next, a third embodiment will be described with reference to FIG.
FIG. 8 is a conceptual diagram of a table in the third embodiment of the present invention.
In the present embodiment, a memory (not shown) mounted on the apparatus main body 20 stores a table as shown in FIG. The table associates the depth of the intersection point P with the optimum transmission frequency, reception frequency, display depth, and dynamic range for each depth.

  When the intersection point P is detected during the ultrasonic diagnosis, a table stored in the memory is referred to, and the optimum transmission frequency, reception frequency, display depth, and dynamic range are selected for the depth of the intersection point P. Is done. Therefore, since the ultrasonic diagnosis is performed under conditions optimal for the subject and the site, the image quality of the diagnostic image displayed on the monitor 35 is very high.

  In the present embodiment, the conditions associated with the intersection point P are a transmission frequency, a reception frequency, a display depth, and a dynamic range. However, the present invention is not limited to this. For example, including reception filter characteristics, transmission sound pressure, post process curve, transmission sound pressure, display width, display frequency, transmission beam number, reception beam number, simultaneous reception beam number, image processing coefficient, transmission waveform, transmission wave number, etc. May be.

  The present invention is not limited to the above-described embodiments as they are, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. Moreover, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, you may combine suitably the component covering different embodiment.

1 is a block diagram of an ultrasonic diagnostic apparatus according to a first embodiment of the present invention. The graph of the weighting coefficient in the same embodiment. The flowchart regarding the production | generation process of the diagnostic image when the setting sequence of the weighting coefficient in the embodiment is operating. The graph of the noise gain and signal gain in the same embodiment. The diagnostic image of the phantom which has the attenuation factor of 0.7 [dB / MHz * cm] in the embodiment. The diagnostic image of the phantom which has the attenuation factor of 0.3 [dB / MHz * cm] in the embodiment. The flowchart regarding the production | generation process of the diagnostic image when the setting sequence of the weighting coefficient in the 2nd Embodiment of this invention is operate | moving. The conceptual diagram of the table in the 3rd Embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 21 ... Transmission / reception part (transmission / reception means), 23 ... Addition part (component extraction means), 29 ... Synthesis | combination part (signal synthesis | combination means), 31 ... Gain adjustment part (gain calculation means), 32 ... Weight coefficient calculation part (weight coefficient calculation) Means), 35 ... monitor (display means), 36 ... instruction switch (instruction means), 37 ... signal generation section (signal generation means), WA ... weighting coefficient (first weighting coefficient), WC ... weighting coefficient (second) EA ... first echo signal (second component), EB ... second echo signal, EC ... third echo signal (first component), GN ... noise gain (second gain) ), GC ... signal gain (first gain), GD ... signal gain (third gain), G ... display gain, SA ... first image signal, SC ... second image signal, SD ... third. Image signal.

Claims (12)

In an ultrasonic diagnostic apparatus that scans a subject with ultrasound and obtains a diagnostic image of the subject,
A transmitter / receiver for transmitting ultrasonic waves to the subject and receiving an echo signal from the subject, and receiving noise;
Component extraction means for extracting first and second components from the echo signal;
Signal generating means for generating a first signal based on the first component and generating a second signal based on the second component;
Based on the first signal, a first gain for making the intensity of the first signal constant in the depth direction of the subject is calculated, and the intensity of the noise is calculated based on the noise. Gain calculating means for calculating a second gain to be constant in the depth direction;
Weighting factor calculating means for calculating a first weighting factor relating to the first signal and a second weighting factor relating to the second signal based on the first and second gains;
Signal combining means for multiplying the first signal by a first weighting factor, multiplying the second signal by a second weighting factor, and adding them to generate a third signal;
An ultrasonic diagnostic apparatus comprising: display means for displaying the diagnostic image based on the third signal. The transmitting / receiving means transmits two types of ultrasonic waves whose phases are inverted to each of a plurality of scanning lines, and receives first and second echo signals corresponding to the two types of ultrasonic waves for each scanning line. ,
The component extraction means adds the first and second echo signals for each scanning line to extract the first component, and subtracts the first and second echo signals for each scanning line. The ultrasonic diagnostic apparatus according to claim 1, wherein the second component is extracted. The transmitting / receiving means transmits two types of ultrasonic waves whose phases are inverted to each of a plurality of scanning lines, and receives first and second echo signals corresponding to the two types of ultrasonic waves for each scanning line. ,
The component extraction means extracts the first component by adding the first and second echo signals for each scanning line, and outputs the first echo signal or the second echo signal to the second The ultrasonic diagnostic apparatus according to claim 1, wherein the ultrasonic diagnostic apparatus is extracted as a component.   The component extraction means extracts the first component by applying a first filter to the echo signal, and extracts the second component by applying a second filter to the echo signal. The ultrasonic diagnostic apparatus according to claim 1.   The gain calculating means calculates a third gain for making the intensity of the third signal constant in the depth direction of the subject based on the third signal, and the second and third gains. The ultrasonic diagnostic apparatus according to claim 1, wherein a gain setting optimum for displaying the diagnostic image is set based on the above.   The ultrasonic diagnostic apparatus according to claim 1, further comprising an instruction unit that causes the weighting factor calculating unit to execute the calculation of the first and second weighting factors.   Based on the first and second gains, transmission frequency, reception frequency, reception filter characteristics, transmission sound pressure, display depth, dynamic range, post process curve, transmission sound pressure, display width, display frequency, number of transmission beams, The ultrasonic diagnostic apparatus according to claim 1, wherein at least one setting condition of a reception beam number, a simultaneous reception beam number, an image processing coefficient, a transmission waveform, and a transmission wave number is designated.   The ultrasonic diagnostic apparatus according to claim 7, wherein the setting condition is determined in advance.   The ultrasonic diagnostic apparatus according to claim 1, wherein the display unit displays the diagnostic image as a 3D video or a 4D video. The first component is a harmonic component of the echo signal,
The ultrasonic diagnostic apparatus according to claim 1, wherein the second component is a fundamental wave component of the echo signal. The first component is a harmonic component of the echo signal,
The ultrasonic diagnostic apparatus according to claim 1, wherein the second component is the echo signal itself. In the ultrasonic diagnostic apparatus comprising a transmitting / receiving means for transmitting an ultrasonic wave to the subject and receiving an echo signal from the subject and receiving noise,
A component extraction function for extracting the first and second components from the echo signal;
Signal generating means for generating a first signal based on the first component and generating a second signal based on the second component;
Based on the first signal, a first gain for making the intensity of the first signal constant in the depth direction of the subject is calculated, and the intensity of the noise is calculated based on the noise. A gain calculating function for calculating a second gain to be constant in the depth direction;
A weighting factor calculation function for calculating a first weighting factor relating to the first component and a second weighting factor relating to the second component based on the first and second gains;
A signal synthesis function for multiplying the first component by a first weighting factor, multiplying the second component by a second weighting factor, and adding them to generate a third signal;
A display function for displaying the diagnostic image based on the third signal;
A control program for an ultrasonic diagnostic apparatus, characterized in that

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