JP2007167626A - Ultrasonographic device, ultrasonographic device control program, and ultrasonic signal processing program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ultrasonographic device or the like, capable of generating ultrasonic images without a lot of artifacts, or insufficient sensitivity even to a depth part. <P>SOLUTION: The device is provided with a transmitter/receiver part 21 to transmit two kinds of ultrasonic waves of reverse phases respectively to a plurality of scan lines, and receive a first and a second echo signals EA and EB corresponding to the two kinds of ultrasonic waves respectively for the scan lines, a first addition part 23 to add the first and the second echo signals EA and EB by every scan line to generate a third echo signal EC, a first signal generating means to generate a first processed signal SA based on the first echo signal EA, and a second processed signal SC based on the third echo signal EC, a second addition part 29 to generate a third processed signal SD based on the first and the second processed signals SA and SC, an image processing part 30 to generate an ultrasonic image based on the third processed signal SD, and a display monitor 33 to display the ultrasonic image. <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 included in an echo signal from the living tissue is often used. However, the technique using the fundamental wave of the echo signal often causes artifacts (virtual images), resulting in a problem that the image quality of the diagnostic image is deteriorated.

  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 inversion (PI) method is known (see, for example, Non-Patent Document 1). In this pulse inversion 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 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, by subtracting these two echo signals and removing the overlapping component, the echo component from the disappeared and deformed contrast agent bubble is extracted.

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 difference signal obtained from these two echo signals reflects the echo signal from the disappeared and deformed contrast agent bubble. 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.
JP 2004-298620 A JP-A-8-336527 Ariru Kaoru, Kamakura Tomio, "Nonlinear Propagation of Ultrasonic Pulses", Science Technique, US89-23, P53

  However, tissue nonlinear acoustic imaging has a problem that sensitivity is insufficient in a deep part of an ultrasound image, compared to a method of imaging a tomographic structure of a biological tissue from a fundamental wave included in an echo signal.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an ultrasonic diagnostic apparatus and an ultrasonic diagnostic apparatus that can generate an ultrasonic image with few artifacts and lacking sensitivity even in a deep part. The object is to provide an apparatus control program and an ultrasonic signal processing program.

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

  According to a first aspect of the present invention, two types of ultrasonic waves whose phases are inverted are transmitted to each of a plurality of scanning lines, and the first and second types correspond to the two types of ultrasonic waves for each scanning line. A transmission / reception unit for receiving the echo signal, a nonlinear signal acquisition unit for acquiring a nonlinear signal by adding the first and second echo signals received by the transmission / reception unit, and a first received by the transmission / reception unit A fundamental wave signal acquisition unit that acquires a fundamental wave signal including an echo signal or a second echo signal, a synthesized signal generation unit that generates a synthesized signal from the nonlinear signal and the fundamental wave signal, and an image based on the synthesized signal And an image display unit for displaying the image.

A second viewpoint of the present invention is a transmission / reception unit that transmits / receives an ultrasonic wave including a first frequency component and a second frequency component higher than the first frequency component for each of a plurality of scanning lines;
Based on the transmission / reception of the ultrasonic wave, a nonlinear component acquisition unit that acquires a nonlinear signal including a difference sound component of the first and second frequency components; and based on the transmission / reception of the ultrasonic wave, the first and second A fundamental wave signal acquisition unit for acquiring a fundamental wave signal including a fundamental wave component including a frequency component, a synthesized signal generating unit for generating a synthesized signal from the nonlinear signal and the fundamental wave signal, and an image based on the synthesized signal An ultrasonic diagnostic apparatus comprising: a display unit that displays

  According to a third aspect of the present invention, two types of ultrasonic waves whose phases are inverted are transmitted to each of a plurality of scanning lines, and the first and second types correspond to the two types of ultrasonic waves for each scanning line. A transmission / reception unit that receives the echo signal, a first nonlinear signal acquisition unit that adds the first and second echo signals received by the transmission / reception unit to acquire a nonlinear signal, and a first received by the transmission / reception unit, A fundamental signal acquisition unit that subtracts a second echo signal to acquire a fundamental signal, a composite signal generation unit that generates a composite signal from the nonlinear signal and the fundamental signal, and an image based on the composite signal. An ultrasonic diagnostic apparatus comprising: an image display unit for displaying.

  According to a fourth aspect of the present invention, for each of a plurality of scanning lines, there are two types of superpositions that each include a first frequency component and a second frequency component higher than the first frequency component, and whose phases are inverted. A transmission / reception unit that transmits a sound wave and receives first and second echo signals corresponding to the two types of ultrasonic waves for each of the scanning lines, and based on the transmission / reception of the ultrasonic waves, the first and second A non-linear component acquisition unit that acquires a non-linear signal including a difference sound component of a frequency component; and a fundamental wave signal acquisition unit that subtracts the first and second echo signals received by the transmission / reception unit to acquire a fundamental wave signal; An ultrasonic diagnostic apparatus comprising: a combined signal generating unit that generates a combined signal from the nonlinear signal and the fundamental wave signal; and a display unit that displays an image based on the combined signal. .

  A fifth aspect of the present invention is a program for controlling an ultrasonic diagnostic apparatus, wherein two types of ultrasonic waves whose phases are inverted are transmitted to each of the plurality of scanning lines to the ultrasonic diagnostic apparatus. And a non-linear signal acquisition function for acquiring a non-linear signal by adding first and second echo signals obtained by receiving reflected waves corresponding to the two types of ultrasonic waves for each scanning line A fundamental wave acquisition function for acquiring a fundamental wave signal including the first echo signal or the second echo signal, a generation function for generating a synthesized signal from the nonlinear signal and the fundamental wave signal, and the synthesis An ultrasonic diagnostic apparatus control program that realizes a display function for displaying an image based on a signal.

  According to a sixth aspect of the present invention, there is provided a program for processing an ultrasonic signal, wherein a second frequency higher than the first frequency component and the first frequency component for each of the plurality of scanning lines is stored in the computer. A non-linear signal acquisition function for acquiring a non-linear signal including a difference sound component of the first and second frequency components from an echo signal obtained by transmitting and receiving an ultrasonic wave including the frequency component of A fundamental wave signal acquisition function for acquiring a fundamental wave signal including a fundamental wave component including a frequency component; a generation function for generating a synthesized signal from the nonlinear signal and the fundamental wave signal; and an image based on the synthesized signal is displayed. An ultrasonic signal processing program characterized by realizing a display function.

  A seventh aspect of the present invention is a program for controlling an ultrasonic diagnostic apparatus, wherein two types of ultrasonic waves whose phases are inverted are transmitted to each of the plurality of scanning lines to the ultrasonic diagnostic apparatus. And a non-linear signal acquisition function for acquiring a non-linear signal by adding first and second echo signals obtained by receiving reflected waves corresponding to the two types of ultrasonic waves for each scanning line A fundamental wave signal acquisition function for subtracting the first and second echo signals to acquire a fundamental wave signal, a generation function for generating a synthesized signal from the nonlinear signal and the fundamental wave signal, and the synthesized signal And a display function for displaying an image based on the ultrasonic diagnostic apparatus control program.

  According to an eighth aspect of the present invention, there is provided a program for controlling an ultrasonic diagnostic apparatus, wherein the ultrasonic diagnostic apparatus includes a first frequency component and the first frequency for each of a plurality of scanning lines. Obtained by receiving a reflected wave corresponding to the two types of ultrasonic waves for each scanning line, and a transmission function for transmitting two types of ultrasonic waves whose phase is inverted including a second frequency component higher than the frequency component of A non-linear signal acquisition function for acquiring a non-linear signal including a difference sound component of the first and second frequency components from the first and second echo signals, and subtracting the first and second echo signals A fundamental wave acquisition function for acquiring a fundamental wave signal, a generation function for generating a synthesized signal from the nonlinear signal and the fundamental wave signal, and a display function for displaying an image based on the synthesized signal are realized. Ultrasound examination Is a device control program.

  As described above, according to the present invention, it is possible to realize an ultrasonic diagnostic apparatus, an ultrasonic diagnostic apparatus control program, and an ultrasonic signal processing program that are capable of generating an ultrasonic image that has few artifacts and does not have insufficient sensitivity even in the deep part. it can.

Hereinafter, first to eighth embodiments of the present invention will be described in detail with reference to the drawings.
(First embodiment)
First, a first embodiment of the present invention will be described with reference to FIGS. 1 and 2.
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 includes an ultrasonic probe 10 and an apparatus main body 20.

  The ultrasonic probe 10 is applied to the body surface of a subject and actually transmits / receives ultrasonic waves, and a piezoelectric vibrator such as a piezoelectric ceramic is provided at the tip thereof. These piezoelectric vibrators are arranged in parallel at predetermined intervals, and each form a so-called channel.

  The apparatus body 20 includes a transmission / reception unit (transmission / reception unit) 21, a first memory 22, a first addition unit (addition unit) 23, a detection unit 24, a filter unit 25, an envelope unit 26, a log compression unit 27, a second Memory 28, second addition unit (second signal processing unit) 29, image processing unit (image generation unit) 30, frame memory 31, digital scan converter (hereinafter referred to as "DSC") 32, and display monitor ( Image display means) 33.

  The transmission / reception unit 21 includes a transmission unit 21a for transmitting ultrasonic waves and a reception unit 21b for receiving echo signals from living tissue. An echo signal from the living tissue is received by the transmitting / receiving unit 21 via the ultrasonic probe 10.

  The first memory 22 stores the echo signal received by the transmission / reception unit 21. When the echo signal is input from the transmission / reception unit 21, the first addition unit 23 adds the echo signal and another echo signal stored in the first memory 22. However, when no echo signal is stored in the first memory 22, the echo signal from the transmission / reception unit 21 passes through the first addition unit 23.

  The detector 24 detects the echo signal from the first 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 to remove unnecessary components such as noise.

  The envelope unit 26 applies an envelope to the echo signal from the filter unit 25 and extracts an envelope signal. The log compression unit 27 performs log compression on the envelope signal from the envelope unit 26 to generate a processing signal.

  That is, the detection unit 24, the filter unit 25, the envelope unit 26, and the log compression unit 27 process the echo signal from the first addition unit 24 to generate a processing signal actually used for image construction. Therefore, a signal conversion unit (first signal processing means) 36 is configured.

  The second memory 28 stores the output of the first signal processing means, that is, the processing signal from the Log compression unit 27. The second adder 29 multiplies the processed signal stored in the second memory 28 and the processed signal from the log compressing unit 27 by applying a weight coefficient, and adds them. As will be described later, these weighting factors are predetermined according to the depth of the subject, and are stored in a storage unit (not shown) of the ultrasonic diagnostic apparatus.

  The image processing unit 30 performs various types of image processing on the processing signal from the second addition unit 29 to generate an image frame. The frame memory 31 sequentially stores image frames from the image processing unit 30.

  The DSC 32 converts the 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 display monitor 33 displays the image data from the DSC 32 as an ultrasonic image.

(Image generation by ultrasonic diagnostic equipment)
In the ultrasonic scanning in the present embodiment, two ultrasonic waves whose phases are inverted by 180 degrees, that is, first and second ultrasonic waves are continuously transmitted for each scanning line. These first and second ultrasonic waves correspond to two echo signals which are reflected by a discontinuous surface of acoustic impedance in the subject and whose phases are inverted by 180 degrees, that is, the first and second ultrasonic waves. The first and second echo signals EA and EB are received by the transmission / reception unit 21. The first and second echo signals EA and EB contain both the fundamental wave component and the harmonic component, but the harmonic component is extremely small compared to the fundamental wave component, so that the echo that reflects the fundamental wave component is reflected. Considered a signal.

  The first echo signal EA received earlier is stored in the first memory 22 and passes through the first adder 23 and proceeds to the detector 24. When the second echo signal EB received late arrives at the first adder 23, the first echo signal EA stored in the first memory 22 and the second echo signal EB Are added to generate a third echo signal EC.

  By the way, as described above, the phases of the first and second echo signals EA and EB are inverted by 180 degrees. 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. . Thereby, the third echo signal EC is an echo signal reflecting the harmonic component from the living tissue.

  When the third echo signal EC is generated, the first echo signal EA has already passed through the first adder 23. Then, 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, and the first and second processing signals SA and SC are obtained. Since the first and second processed signals SA and SC are generated based on the first and third echo signals EA and EC, the processed signals reflecting the fundamental component and the harmonic component, respectively. It has become.

  The first processing signal SA output from the Log compression unit 27 is temporarily stored in the second memory 28. Then, when the second processed signal SC output from the Log compressing unit 27 with a delay reaches the second adding unit 29, the weighting coefficient WA is added to the first processed signal SA stored in the second memory 28. The weighted coefficient WC is applied to the second processed signal SC that has been multiplied and reached the second adder 29, and these are further added. As a result, a third processed signal SD composed of the first processed signal SA and the second processed signal SC is generated.

The third processed signal SD is obtained by the first processed signal SA and the second processed signal SC.
“SD = SA × WA + SC × WC”
It is expressed.

  The weighting factors WA and WC are predetermined and are stored in a storage unit (not shown) of the ultrasonic diagnostic apparatus.

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

  The contribution ratio between the fundamental wave component and the harmonic component in the third processed 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 processing signal SD reflects the fundamental wave component more. In addition, when the weighting factor WA is small and the weighting factor WC is large, the third processed signal SD reflects the harmonic component more.

FIG. 2 is a graph of the weighting factors WA and WC according to the embodiment.
Referring to FIG. 2, the weight 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 processing signal SD, the harmonic component is more reflected in the shallow portion and the fundamental wave component is more reflected in the deep portion.

  The third processing signal SD is subjected to various types of image processing by the image processing unit 30 to be converted into an image frame, and is then sequentially stored in the frame memory 31. The image frames stored in the frame memory 31 are scan-converted by the DSC 32 and displayed on the display monitor 33 one after another as an ultrasonic image. By selecting the display method, the internal structure of the subject can be displayed on the display monitor 33 as a moving image. An operator such as a doctor makes a diagnosis while viewing this ultrasonic image.

(Operation by this embodiment)
The third processed signal SD in the present embodiment is obtained by multiplying the first processed signal SA reflecting the fundamental wave component by the weighting coefficient WA and multiplying the second processed signal SC reflecting the harmonic component by the weighted coefficient WC. Are generated by adding them. The weight coefficient WA of the first processed 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 processed signal SC is set at the shallow portion of the subject. It is set to be small and large in the deep part.

  Therefore, the ultrasonic image generated based on the third processing signal SD is a reflection of the harmonic component more in the shallow part of the subject and the reflection of the fundamental wave component in the deep part. That is, the deep part of the subject is imaged based on the fundamental wave component. As a result, 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.

  Further, since the shallow part of the subject is imaged based on the harmonic component, the occurrence of artifacts is remarkably suppressed as compared to the case where the image is made using only the fundamental wave component.

  As described above, according to the present embodiment, an ultrasonic image with few artifacts and sufficient sensitivity at a deep portion can be obtained.

  In the present embodiment, no mention is made of the frequency bands of the first and second ultrasonic waves. However, the first and second ultrasonic waves may have first and second frequency components. In this case, the third echo signal EC includes a difference sound component of the first and second frequency components. Therefore, for example, the third echo signal EC is filtered and only the difference sound component is extracted therefrom. Then, a second processed signal SC is generated based on the extracted difference sound component. Needless to say, the difference sound component is one of the harmonic components.

  As described above, even when the second processed signal SC is generated based on the difference sound component, the first and second processed signals SA and SC are the processed signal reflecting the fundamental wave component and the harmonic component, respectively. Therefore, if the first and second processed signals SA and SC are imaged by applying weighting coefficients, respectively, an ultrasonic image with good image quality can be obtained as described above.

(Second Embodiment)
Next, a second embodiment of the present invention will be described using FIG. 3 and FIG. In the following description, the description of the same configuration and operation as in the first embodiment is omitted.

FIG. 3 is a block diagram of an ultrasonic diagnostic apparatus according to the second embodiment of the present invention.
As shown in FIG. 3, in the present embodiment, an adder / subtractor (adder, subtractor) 23A is used instead of the first adder 23 in the first embodiment.

  In addition to the function of the first adder 23 in the first embodiment, the adder / subtractor 23 </ b> A receives the echo signal and the other stored in the first memory 22 when the echo signal is input from the transmitter / receiver 21. It has a function to subtract the echo signal. In addition, subtraction is calculating | requiring the difference between echo signals.

(Image generation by ultrasonic diagnostic equipment)
In the ultrasonic scanning in the present embodiment, two ultrasonic waves whose phases are inverted by 180 degrees, that is, first and second ultrasonic waves are continuously transmitted for each scanning line. These first and second ultrasonic waves correspond to two echo signals which are reflected by a discontinuous surface of acoustic impedance in the subject and whose phases are inverted by 180 degrees, that is, the first and second ultrasonic waves. The first and second echo signals EA and EB are received by the transmission / reception unit 21.

  The first echo signal EA previously received is temporarily stored in the first memory 22. When the second echo signal EB received late arrives at the adder / subtractor 23A, the first echo signal EA stored in the first memory 22 and the second echo signal EB are added. A third echo signal EC is generated. Subsequently, the first echo signal EA stored in the first memory 22 and the second echo signal EB received with a delay are subtracted to generate a fourth echo signal EC ′.

  By the way, as described above, the phases of the first and second echo signals EA and EB are inverted by 180 degrees. 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. . Thereby, the third echo signal EC becomes an echo signal reflecting the harmonic component from the living tissue. Conversely, when the first and second echo signals EA and EB are subtracted, the harmonic components contained in the first and second echo signals EA and EB are canceled, and only the fundamental component is doubled. To be emphasized. Thereby, the fourth echo signal EC ′ is an echo signal reflecting the fundamental wave component from the living tissue.

  When the fourth echo signal EC ′ is generated, the third echo signal EC has already passed through the adder / subtractor 23A. The preceding third echo signal EC and fourth echo signal EC ′ are respectively detected by the detection unit 24, the filter unit 25, the envelope unit 26, and the Log compression unit 27. The compression processing is sequentially performed to obtain first and second processed signals SC and SC ′. Since the first and second processed signals SC and SC ′ are generated based on the third and fourth processed signals EC and EC ′, the harmonic component and the fundamental wave component are reflected, respectively. It is a processing signal.

  The first processed signal SC output from the log compressing unit 27 is temporarily stored in the second memory 28. When the second processed signal SC ′ output from the Log compressing unit 27 with a delay arrives at the second adding unit 29, the weighting factor WC is applied to the first processed signal SC stored in the second memory 28. And the second processed signal SC ′ reaching the second adder 29 is multiplied by the weighting coefficient WC ′ and further added. As a result, a third processed signal SD composed of the first processed signal SC and the second processed signal SC ′ is generated.

The third processed signal SD is obtained by the first processed signal SC and the second processed signal SC ′.
“SD = SC × WC + SC ′ × WC ′”
It is expressed.

  The weighting factors WC and WC ′ are predetermined and are stored in a storage unit (not shown) of the ultrasonic diagnostic apparatus.

  By the way, as described above, the first processed signal SC is a processed signal reflecting the harmonic component, and the second processed signal SC ′ is a processed signal reflecting the fundamental wave component. Therefore, the third processing signal SD is a processing signal composed of a harmonic component and a fundamental wave component.

  The contribution ratio of the harmonic component and the fundamental wave component in the third processed signal SD is determined by the magnitude relationship between the weighting factors WC and WC ′. For example, when the weighting factor WC is large and the weighting factor WC ′ is small, the third processed signal SD reflects the harmonic component more. Further, when the weighting factor WC is small and the weighting factor WC ′ is large, the third processing signal SD reflects the fundamental wave component more.

FIG. 4 is a graph of the weighting factors WC and WC ′ according to the embodiment.
Referring to FIG. 4, the weighting coefficient WC is large at the shallow portion and decreases as it goes to the deep portion. On the other hand, the weighting coefficient WC ′ is small at the shallow portion and increases as it goes to the deep portion. In the intermediate portion, the weighting factors WC and WC ′ are close to each other. Therefore, in the third processing signal SD, the harmonic component is more reflected in the shallow portion and the fundamental wave component is more reflected in the deep portion. Furthermore, the curve of the weighting factor WC ′ expressing the contribution ratio of the fundamental wave component is gentler than the curve of the weighting factor WA in the first embodiment.

  The third processing signal SD is subjected to various types of image processing by the image processing unit 30 to be converted into an image frame, and is then sequentially stored in the frame memory 31. The image frames stored in the frame memory 31 are scan-converted by the DSC 32 and displayed on the display monitor 33 as an ultrasonic image. Depending on the selection of the display method, the internal structure of the subject may be displayed as a moving image on the display monitor 33. An operator such as a doctor makes a diagnosis while viewing this ultrasonic image.

(Operation by this embodiment)
The second processed signal SC ′ in the present embodiment is a processed signal that mainly reflects the fundamental wave component, like the first processed signal SA in the first embodiment, but the fundamental wave component is emphasized twice. Since it is generated based on the fourth echo signal EC ′, it has about twice the intensity of the first processed signal SA in the first embodiment.

  Therefore, the scale of the weighting factor WC ′ expressing the contribution ratio of the fundamental wave component is reduced to about ½. Therefore, in the first embodiment, even if the weighting factor WA is maximized, the deep part of the living tissue does not have sufficient brightness. Even in such a case, the present embodiment can sufficiently cope.

  In the present embodiment, the frequency band of the first and second ultrasonic waves is not mentioned. However, the first and second ultrasonic waves may have first and second frequency components. In this case, as described in the first embodiment, the third echo signal EC is filtered to extract only the difference sound component therefrom. Then, a second processed signal SC is generated based on the extracted difference sound component.

  Thus, even when the second processed signal SC is generated based on the difference sound component, the first and second processed signals SC and SC ′ are processed signals reflecting the fundamental wave component and the harmonic component, respectively. Therefore, if the first and second processed signals SC and SC ′ are imaged by applying weighting coefficients, respectively, an ultrasonic image with good image quality can be obtained as described above.

(Third embodiment)
Next, a third embodiment of the present invention will be described with reference to FIG. In the following description, the description of the same configuration and operation as those in the first and second embodiments is omitted.

FIG. 5 is a block diagram of an ultrasonic diagnostic apparatus according to the third embodiment of the present invention.
As shown in FIG. 5, the present embodiment is an example in which a so-called frequency compound is applied to the ultrasonic diagnostic apparatus according to the first embodiment. Therefore, in the ultrasonic diagnostic apparatus according to the present embodiment, the subsequent stage of the transmission / reception unit 21 is separated into four paths P1 to P4 and connected again in the previous stage of the second addition unit 29.

  The configuration of each of the paths P1 to P4, that is, the configuration between the transmission / reception unit 21 and the second addition unit 29 is almost the same as that of the first embodiment. The only difference is the frequency of the detection unit 24 and the frequency of the filter unit 25.

  That is, the detection unit 24 of the paths P1 to P4 in the present embodiment detects the first and second echo signals EA and EB received by the transmission / reception unit 21 at different frequencies, that is, 1 MHz, 2 MHz, 3 MHz, and 4 MHz. . Further, the filter units 25 of the paths P1 to P4 respectively apply frequency filters corresponding to the detection processing.

(Image generation by ultrasonic diagnostic equipment)
The first and second echo signals EA and EB received by the transmission / reception unit 21 are separated into paths P1 to P4, respectively, and signal processing is performed for each path. For example, the first and second echo signals EA1 and EB1 sent to the path P1 are processed in the same manner as in the first embodiment, and the first processed signal SA1 reflecting the fundamental wave component and the harmonic component The second processed signal SC1 reflecting SC1 is sequentially output from the Log compression unit 27. The first and second processed signals SA1 and SC1 correspond to the first and second processed signals SA and SC in the first embodiment.

  By executing the processing as described above in each of the paths P1 to P4, eight types of processing signals, that is, the first processing signals SA1 to SA4 and the second processing signals SC1 to SC4 are generated. Note that the first processing signals SA1 to SA4 are processing signals in which the fundamental wave components are reflected, and the second processing signals SC1 to SC4 are processing signals in which the harmonic components are reflected.

  By the way, as described above, the frequency of the detection process and the frequency of the filter process are different for each path. Accordingly, the first processing signals SA1 to SA4 have different frequencies, and the second processing signals SC1 to SC4 also have different frequencies.

  The first processed signals SA1 to SA4 output from the Log compressing unit 27 of the paths P1 to P4 are temporarily stored in the second memory 28. Then, when the second processed signals SC1 to SC4 output from the Log compressing unit 27 with a delay arrive at the second adding unit 29, the first processed signals SA1 to SA4 stored in the second memory 28 are displayed. The weighting factors WA1 to WA4 determined in advance are respectively multiplied, the weighting factors WB1 to WB4 are respectively multiplied to the second processed signals SC1 to SC4 reaching the second adding unit 29, and all of these are added. The Thereby, a third processed signal SD composed of the first processed signals SA1 to SA4 and the second processed signals SC1 to SC4 is generated.

The third processed signal SD is obtained by the first processed signals SA1 to SA4 and the second processed signals SC1 to SC4.
“SD = SA1 × WA1 + SA2 × WA2 + SA3 × WA3 + SA4 × WA4 + SC1 × WC1 + SC2 × WC2 + SC3 × WC3 + SC4 × WC4”
It is expressed.

  By the way, as described above, the first processing signals SA1 to SA4 are processing signals reflecting the fundamental wave components, and the third processing signals SC1 to SC4 are processing signals reflecting the harmonic components. Further, the first processing signals SA1 to SA4 have different frequencies, and the third processing signals SC1 to SC4 also have different frequencies.

  That is, the third processed signal SD is a processed signal composed of four types of fundamental wave components having different frequencies and four types of harmonic components having different frequencies.

  The third processing signal SD is subjected to various types of image processing by the image processing unit 30 to be converted into an image frame, and is then sequentially stored in the frame memory 31. The image frames stored in the frame memory 31 are scan-converted by the DSC 32 and displayed on the display monitor 33 one after another as an ultrasonic image. An operator such as a doctor makes a diagnosis while viewing this ultrasonic image.

(Operation by this embodiment)
The third processed signal SD in the present embodiment is composed of four types of fundamental wave components having different frequencies and four types of harmonic components having different frequencies. Therefore, the ultrasonic image generated based on the third processing signal SD becomes extremely dense with no speckle feeling due to the compound effect. As a result, since the details of the living tissue in the ultrasonic image are displayed in detail, the diagnostic ability is improved as compared with the conventional case.

  In this embodiment, the frequency compound is applied to the ultrasonic diagnostic apparatus according to the first embodiment. However, the present invention is not limited to this, and the ultrasonic diagnostic apparatus according to the second embodiment is applied. On the other hand, a frequency compound may be applied.

(Fourth embodiment)
Next, a fourth embodiment of the present invention will be described with reference to FIGS. In the following description, the description of the same configuration and operation as those in the first to third embodiments is omitted.

FIG. 6 is a block diagram around the interface unit 34 of the ultrasonic diagnostic apparatus according to the fourth embodiment of the present invention, and FIG. 7 is a graph of the weighting factor WC according to the same embodiment.
As shown in FIG. 6, the present embodiment is obtained by adding an interface unit (variable means) 34 to the ultrasonic diagnostic apparatus in the first embodiment. The interface unit 34 is for inputting a weighting factor designated by an operator such as a doctor. As the weighting coefficient in the present embodiment, a weighting coefficient that changes linearly with respect to the depth is used. As the interface unit 34, for example, a dial, a slide type switch, a button, a touch panel type switch, or the like is used.

  The second addition unit 29 performs weighting using the weighting coefficient input from the interface unit 34, and generates a third processing signal SD used for generating an ultrasonic image. For example, assuming that the weighting factors WA and WC have a relationship of “WC = 1−WA”, as shown in FIG. 7, only one of the weighting factors WA is adjusted, and the inclination thereof is set to (1) to (N ), The ratio of the fundamental wave component and the harmonic component in the ultrasonic image can be freely determined. Further, depending on the form of the interface unit 34, it is possible to cope with extremely subtle changes in the weighting coefficient.

  Therefore, according to the ultrasonic diagnostic apparatus in the present embodiment, an operator such as a doctor can obtain an optimal image for diagnosis simply by adjusting the interface unit 34 while viewing the ultrasonic image. Also improved usability.

  In this embodiment, the example in which the interface unit 34 is added to the ultrasonic diagnostic apparatus in the first embodiment is described. However, the present invention is not limited to this. For example, the second and third embodiments are described. An interface unit 34 may be added to the form. In particular, in the ultrasonic diagnostic apparatus according to the third embodiment, since there are eight types of weighting coefficients, extremely diverse ultrasonic images are generated by adjusting these numerical values.

(Fifth embodiment)
Next, a fifth embodiment of the present invention will be described with reference to FIGS. In the following description, the description of the same configuration and operation as those in the first to fourth embodiments is omitted.

8 is a block diagram around the weight coefficient table 35 of the ultrasonic diagnostic apparatus according to the fifth embodiment of the present invention, and FIG. 9 is a weight coefficient WC, WA (1), WA (1),... WA according to the same embodiment. It is a graph of (n).
As shown in FIG. 8, in the present embodiment, an interface unit (variable means) 34A and a weighting coefficient table 35 are added to the ultrasonic diagnostic apparatus according to the first embodiment.

  The interface unit 34A is for inputting various setting information such as a transmission frequency of ultrasonic waves and weighting factors designated by an operator such as a doctor. As shown in FIG. 9, the weighting factor table 35 stores weighting factors WC and weighting factors WA (1), WA (2),... WA (n) corresponding to ultrasonic transmission frequencies and display depths. ing.

  When setting information, that is, transmission frequency and display depth are input from the interface unit 34A, WA (i) corresponding to the setting information is automatically selected from the weighting coefficient table 35, and the weighting coefficients WC and WA (i) are set. Input to the second adder 29. The second adder 29 performs weighting based on the weighting factors WC and WA (i) input from the weighting factor table 35, and generates a third processing signal SD used for generating an ultrasound image.

  Therefore, since an ultrasonic image corresponding to the transmission frequency of ultrasonic waves input from the interface unit 34A and the display depth is generated, the operator can freely change the transmission frequency without worrying about a decrease in sensitivity. . As a result, variations in the setting conditions increase, so that the diagnostic ability is improved as compared with the prior art.

  In addition, simply by inputting the setting condition from the interface unit 34A, an ultrasonic image corresponding to the setting condition is automatically generated. Compared to the case where all condition settings must be input for each diagnosis, The burden on the operator is drastically reduced.

  In this embodiment, the example in which the interface unit 34 is added to the ultrasonic diagnostic apparatus in the first embodiment is described. However, the present invention is not limited to this. For example, the second and third embodiments are described. The interface unit 34A and the weight coefficient table 35 may be added to the form.

  In the first to fifth embodiments, the B-mode image has been particularly described. However, the present invention can be applied to generation of an ultrasonic image other than the B-mode. For example, if the present invention is applied to the generation of an M-mode image or a three-dimensional image, even when the display mode is switched to the M mode or the three-dimensional mode, the M-mode image or the three-dimensional image with sufficient sensitivity in the deep part of the subject Therefore, it is possible to cope between the modes at the time of diagnosis.

(Sixth embodiment)
First, the first embodiment will be described with reference to FIGS.
FIG. 10 is a block diagram of an ultrasonic diagnostic apparatus according to the sixth embodiment of the present invention.

  As shown in FIG. 10, the ultrasonic diagnostic apparatus according to this embodiment includes an ultrasonic probe 10 and an apparatus 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 weight coefficient calculation unit (weight coefficient calculation unit) 32, a frame memory 31, a DSC 32, a monitor (display unit) 35, And an input unit (instruction means) 36.

  The image processing unit 30 performs various image processing on the image signal from the second addition unit 29. The gain adjusting unit 42 adjusts the gain based on the image signal from the image processing unit 30. The weighting factor calculation unit 40 calculates a weighting factor based on the gain from the gain adjustment unit 42.

(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 and passes through the first adder 23 and proceeds to the detector 24. Then, when the second echo signal EB received later arrives at the first adder 23, it arrives at the first echo signal EA stored in the first memory 22 and the first adder 23. The second echo signal EB thus added 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 first adder 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 reaches the second addition unit 29, the weight coefficient WA is added to the first image signal SA stored in the second memory 28. The weight coefficient WC is applied to the second image signal SC that has been multiplied and reached the second adder 29, and these are further 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 40, and the calculation method will be described in detail later.

  The third image signal SD is stored in the frame memory 31 after being subjected to various image processing by the image processing unit 30. Then, the third image signal SD stored in the frame memory 31 is scan-converted by the DSC 32 and displayed on the image display unit 33 one after another as a diagnostic image. The image display unit 33 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. 11 is a graph of the weighting factors WA and WC in the same embodiment.
As shown in FIG. 11, 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. 12 is a flowchart regarding 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. 12, when the input unit 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, a noise signal from the ultrasonic probe 10 or the apparatus main body 20 is sometimes displayed as white noise on the image display unit 33, and thus may be 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 42 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 42, and a signal gain GC is set so 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 weighting coefficient calculator 40, and based on these noise gain GN and signal gain GC, the weighting 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 second adder 29 as described above and applied to the first and second image signals SA and SC, respectively. It is done. As a result, a third image signal SD composed of the fundamental wave component and the harmonic component is generated (step S7). Then, the generated third image signal SD is successively displayed on the image display unit 33 (step S8).

FIG. 13 is a graph of the noise gain GN and the signal gain GC in the same embodiment.
As shown in FIG. 13, the noise gain GN and the signal gain GC intersect at a certain depth, and the noise gain GN is lower than the signal gain GC in a region deeper than the intersection point P. 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)
FIGS. 14A and 14B are diagnostic images of a phantom having an attenuation rate of 0.7 [dB / MHz · cm] in the embodiment. That is, FIG. 14A shows a case where the setting sequence of the weighting factors WA and WC is not operating, and FIG. 14B 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. 14A, 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. 14B, 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.

  FIGS. 15A and 15B are diagnostic images of a phantom having an attenuation factor of 0.3 [dB / MHz · cm] in the embodiment. That is, FIG. 15A shows a case where the setting sequence of the weighting factors WA and WC is not operating, and FIG. 15B 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. 15A, 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. 15B, the target T is depicted in the deep part of the diagnostic image even when the weighting coefficient WA, WC setting sequence is operating. 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.

  Furthermore, in the present embodiment, the apparatus main body 20 includes an input unit 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, in order to acquire the first echo signal EA reflecting the fundamental wave component and the third echo signal EC reflecting the harmonic component, the addition processing by the first adding unit 23 is performed. It's being used. 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 first adder 23, a first filter that passes only the fundamental wave component from the echo signal received by the transmitter / receiver 21 and a second filter that passes only the harmonic component. A filter may be used.

(Seventh embodiment)
Next, a second embodiment will be described with reference to FIG.
FIG. 16 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. 16, 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 42, 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 adjustment unit 42, 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 42 before the third image signal SD is displayed on the image display unit 33. . 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 image display unit 33 is very clear and does not depict white noise.

(Eighth embodiment)
Next, an eighth embodiment will be described with reference to FIG.
FIG. 17 is a conceptual diagram of a table in the eighth 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 the optimum conditions for the subject and the site, the image quality of the diagnostic image displayed on the image display unit 33 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.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the components without departing from the scope of the invention in the implementation stage. In addition, 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, constituent elements over different embodiments may be appropriately combined.

  As described above, according to the present invention, it is possible to realize an ultrasonic diagnostic apparatus, an ultrasonic diagnostic apparatus control program, and an ultrasonic signal processing program that are capable of generating an ultrasonic image that has few artifacts and does not have insufficient sensitivity even in the deep part. it can.

FIG. 1 is a block diagram of an ultrasonic diagnostic apparatus according to the first embodiment of the present invention. FIG. 2 is a graph of weighting factors according to the embodiment. FIG. 3 is a block diagram of an ultrasonic diagnostic apparatus according to the second embodiment of the present invention. FIG. 4 is a graph of weighting factors according to the embodiment. FIG. 5 is a block diagram of an ultrasonic diagnostic apparatus according to the third embodiment of the present invention. FIG. 6 is a block diagram around the interface unit of the ultrasonic diagnostic apparatus according to the fourth embodiment of the present invention. FIG. 7 is a graph of weighting factors according to the embodiment. FIG. 8 is a block diagram around the weighting coefficient table of the ultrasonic diagnostic apparatus according to the fifth embodiment of the present invention. FIG. 9 is a graph of weighting factors according to the fifth embodiment. FIG. 10 is a block diagram of an ultrasonic diagnostic apparatus according to the sixth embodiment. FIG. 11 is a graph of weighting factors in the sixth embodiment. FIG. 12 is a flowchart relating to a diagnostic image generation process when the weighting coefficient setting sequence in the sixth embodiment is operating. FIG. 13 is a graph of noise gain and signal gain in the sixth embodiment. 14A and 14B are diagnostic images of a phantom having an attenuation rate of 0.7 [dB / MHz · cm] in the sixth embodiment. FIGS. 15A and 15B are phantom diagnostic images having an attenuation rate of 0.3 [dB / MHz · cm] in the sixth embodiment. FIG. 16 is a flowchart relating to a diagnostic image generation process when the weighting coefficient setting sequence according to the seventh embodiment is operating. FIG. 17 is a conceptual diagram of a table in the eighth embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 21 ... Transmission / reception part, 23 ... 1st addition part, 23A ... Addition / subtraction part, 29 ... 2nd addition part, 30 ... Image processing part, 33 ... Display monitor, 34 ... Interface part, 34A ... Interface part, 36 ... Signal Conversion unit, EA ... first echo signal, EB ... second echo signal, EC ... third echo signal, SA ... first processing signal, SC ... second processing signal, SD ... third processing signal , WA ... weighting factor, WC ... weighting factor, WC '... weighting factor, WA (1) ..., WA (2) ... weighting factor, WA (i) ... weighting factor, WA (n) ... weighting factor.

Claims (20)

A transmission / reception unit that transmits two types of ultrasonic waves with inverted phases 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; ,
A nonlinear signal acquisition unit that acquires a nonlinear signal by adding the first and second echo signals received by the transceiver unit;
A fundamental signal acquisition unit that acquires a fundamental signal including the first echo signal or the second echo signal received by the transceiver unit;
A synthesized signal generating unit that generates a synthesized signal from the nonlinear signal and the fundamental signal;
An image display unit for displaying an image based on the combined signal;
An ultrasonic diagnostic apparatus comprising:   The synthesized signal generation unit generates the synthesized signal by adding the weighting coefficients determined according to the depth of the subject to the nonlinear signal and the fundamental wave signal, respectively, and adding them together. The ultrasonic diagnostic apparatus according to claim 1. A gain calculation unit for calculating a first gain for making the nonlinear component constant in the depth direction and a second gain for making the noise component constant in the depth direction;
A weighting factor calculating unit that calculates the respective weighting factors based on the magnitude relationship according to the depth direction of the first gain and the second gain;
The ultrasonic diagnostic apparatus according to claim 2, further comprising:   The weighting factor of the nonlinear component relative to the weighting factor of the fundamental wave signal is relatively smaller at a depth deeper than the depth at which the first gain factor and the second gain factor are equal. The ultrasonic diagnostic apparatus according to claim 3. A transmission / reception unit that transmits / receives an ultrasonic wave including a first frequency component and a second frequency component higher than the first frequency component for each of the plurality of scanning lines;
A nonlinear component acquisition unit that acquires a nonlinear signal including a difference sound component of the first and second frequency components based on transmission and reception of the ultrasonic wave;
A fundamental wave signal acquisition unit for acquiring a fundamental wave signal including a fundamental wave component including the first and second frequency components based on transmission and reception of the ultrasonic wave;
A synthesized signal generating unit that generates a synthesized signal from the nonlinear signal and the fundamental signal;
A display unit for displaying an image based on the combined signal;
An ultrasonic diagnostic apparatus comprising:   The synthesized signal generation unit generates the synthesized signal by adding the weighting coefficients determined according to the depth of the subject to the nonlinear signal and the fundamental wave signal, respectively, and adding them together. The ultrasonic diagnostic apparatus according to claim 5. A gain calculation unit for calculating a first gain for making the nonlinear component constant in the depth direction and a second gain for making the noise component constant in the depth direction;
A weighting factor calculating unit that calculates the respective weighting factors based on the magnitude relationship according to the depth direction of the first gain and the second gain;
The ultrasonic diagnostic apparatus according to claim 6, further comprising:   The weighting factor of the nonlinear component relative to the weighting factor of the fundamental wave signal is relatively smaller at a depth deeper than the depth at which the first gain factor and the second gain factor are equal. The ultrasonic diagnostic apparatus according to claim 7. A transmission / reception unit that transmits two types of ultrasonic waves with inverted phases 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; ,
A nonlinear signal acquisition unit that acquires a nonlinear signal by adding the first and second echo signals received by the transceiver unit;
A fundamental wave signal acquisition unit that acquires a fundamental wave signal by subtracting the first and second echo signals received by the transceiver unit;
A synthesized signal generating unit that generates a synthesized signal from the nonlinear signal and the fundamental signal;
An image display unit for displaying an image based on the combined signal;
An ultrasonic diagnostic apparatus comprising:   The synthesized signal generation unit generates the synthesized signal by adding the weighting coefficients determined according to the depth of the subject to the nonlinear signal and the fundamental wave signal, respectively, and adding them together. The ultrasonic diagnostic apparatus according to claim 9. A gain calculation unit for calculating a first gain for making the nonlinear component constant in the depth direction and a second gain for making the noise component constant in the depth direction;
A weighting factor calculating unit that calculates the respective weighting factors based on the magnitude relationship according to the depth direction of the first gain and the second gain;
The ultrasonic diagnostic apparatus according to claim 10, further comprising:   The weighting factor of the nonlinear component relative to the weighting factor of the fundamental wave signal is relatively smaller at a depth deeper than the depth at which the first gain factor and the second gain factor are equal. The ultrasonic diagnostic apparatus according to claim 11, wherein the apparatus is an ultrasonic diagnostic apparatus. For each of the plurality of scanning lines, two types of ultrasonic waves each including a first frequency component and a second frequency component higher than the first frequency component and having phases inverted are transmitted, A transmission / reception unit for receiving first and second echo signals corresponding to the two types of ultrasonic waves;
A nonlinear component acquisition unit that acquires a nonlinear signal including a difference sound component of the first and second frequency components based on transmission and reception of the ultrasonic wave;
A fundamental wave signal acquisition unit that acquires a fundamental wave signal by subtracting the first and second echo signals received by the transceiver unit;
A synthesized signal generating unit that generates a synthesized signal from the nonlinear signal and the fundamental signal;
A display unit for displaying an image based on the combined signal;
An ultrasonic diagnostic apparatus comprising:   The synthesized signal generation unit generates the synthesized signal by adding the weighting coefficients determined according to the depth of the subject to the nonlinear signal and the fundamental wave signal, respectively, and adding them together. The ultrasonic diagnostic apparatus according to claim 13. A gain calculation unit for calculating a first gain for making the nonlinear component constant in the depth direction and a second gain for making the noise component constant in the depth direction;
A weighting factor calculating unit that calculates the respective weighting factors based on the magnitude relationship according to the depth direction of the first gain and the second gain;
The ultrasonic diagnostic apparatus according to claim 14, further comprising:   The weighting factor of the nonlinear component relative to the weighting factor of the fundamental wave signal is relatively smaller at a depth deeper than the depth at which the first gain factor and the second gain factor are equal. The ultrasonic diagnostic apparatus according to claim 15, characterized in that: A program for controlling an ultrasonic diagnostic apparatus,
In the ultrasonic diagnostic apparatus,
A transmission function for transmitting two types of ultrasonic waves with inverted phases to each of a plurality of scanning lines;
A non-linear signal acquisition function for acquiring a non-linear signal by adding first and second echo signals obtained by receiving reflected waves corresponding to the two types of ultrasonic waves for each scanning line;
A fundamental wave acquisition function for acquiring a fundamental wave signal including the first echo signal or the second echo signal;
A generation function for generating a composite signal from the nonlinear signal and the fundamental signal;
A display function for displaying an image based on the combined signal;
An ultrasonic diagnostic apparatus control program characterized by realizing the above. A program for processing an ultrasonic signal,
On the computer,
For each of the plurality of scanning lines, the first and second frequencies are obtained from an echo signal obtained by transmitting and receiving an ultrasonic wave including a first frequency component and a second frequency component higher than the first frequency component. A nonlinear signal acquisition function for acquiring a nonlinear signal including a difference sound component of the component;
A fundamental wave signal acquisition function for acquiring a fundamental wave signal including a fundamental wave component including the first and second frequency components;
A generation function for generating a composite signal from the nonlinear signal and the fundamental signal;
A display function for displaying an image based on the combined signal;
To realize an ultrasonic signal processing program. A program for controlling an ultrasonic diagnostic apparatus,
In the ultrasonic diagnostic apparatus,
A transmission function for transmitting two types of ultrasonic waves with inverted phases to each of a plurality of scanning lines;
A non-linear signal acquisition function for acquiring a non-linear signal by adding first and second echo signals obtained by receiving reflected waves corresponding to the two types of ultrasonic waves for each scanning line;
A fundamental wave signal acquisition function for subtracting the first and second echo signals to acquire a fundamental wave signal;
A generation function for generating a composite signal from the nonlinear signal and the fundamental signal;
A display function for displaying an image based on the combined signal;
An ultrasonic diagnostic apparatus control program characterized by realizing the above. A program for controlling an ultrasonic diagnostic apparatus,
In the ultrasonic diagnostic apparatus,
A transmission function for transmitting two types of ultrasonic waves, each including a first frequency component and a second frequency component higher than the first frequency component, the phases of which are inverted, for each of the plurality of scanning lines;
From the first and second echo signals obtained by receiving reflected waves corresponding to the two types of ultrasonic waves for each scanning line, a non-linear signal including a difference sound component of the first and second frequency components is obtained. Nonlinear signal acquisition function to acquire,
A fundamental wave acquisition function for subtracting the first and second echo signals to acquire a fundamental wave signal;
A generation function for generating a composite signal from the nonlinear signal and the fundamental signal;
A display function for displaying an image based on the combined signal;
An ultrasonic diagnostic apparatus control program characterized by realizing the above.

Images