JP3644895B2 - Ultrasonic diagnostic equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an ultrasonic diagnostic apparatus, and more particularly to an apparatus for imaging a contrast agent injected into a living body.
[0002]
[Prior art]
A contrast imaging method has been put into practical use in which ultrasound is transmitted to and received from a living body while a contrast agent (ultrasound contrast agent) is injected into the living body, and an ultrasonic image is formed based on the received signal. ing. For such an ultrasonic image, for example, it is desired to clearly display a contrast agent with high luminance against a background of tissue displayed with low luminance.
[0003]
A contrast agent consists of many microbubbles (microbubbles), for example, and a vibration and destruction (disintegration) generate | occur | produce by irradiation of an ultrasonic wave. Conventionally, a harmonic extraction method and a difference extraction method are known as contrast imaging methods.
[0004]
In the above harmonic extraction method, a harmonic component contained in a reception signal obtained by transmission / reception of an ultrasonic wave is extracted by, for example, a BPF (band pass filter), and an ultrasonic image (for example, two-band signal) is used by using the harmonic component. This is a method for forming a B-mode image which is a two-dimensional tomographic image. When the contrast agent is irradiated with ultrasonic waves, vibration and destruction occur in the contrast agent, but the reflected wave generated at that time is distorted, that is, the reflected wave includes harmonics. The harmonic extraction method extracts such harmonics and images them.
[0005]
The difference extraction method described above performs ultrasonic wave transmission / reception twice in a short time in the same direction, calculates the difference between the two received signals obtained thereby, and displays the calculation result as an ultrasonic image To do. The first ultrasonic transmission causes vibration, destruction, and transition in the contrast agent, that is, the property of the contrast agent changes. When the second transmission / reception is performed in this state, a difference is generated between the reception signal by the first transmission / reception and the reception signal by the second transmission / reception. The difference extraction method is to image such a difference. In addition to the case where the phase is the same between the ultrasonic wave transmitted for the first time and the ultrasonic wave transmitted for the second time, a method of inverting the phase is also known.
[0006]
[Problems to be solved by the invention]
However, the living tissue itself also has a non-linear action on ultrasonic waves, that is, the waveform of the ultrasonic waves is distorted even when reflected by the tissue, and the reflected waves from the tissue also contain harmonics. According to the above harmonic extraction method, in a portion where there is little contrast agent, the harmonic component due to the tissue becomes dominant and remarkable, and the harmonic from the contrast agent to be noticed is buried in the ultrasonic image. There is a problem.
[0007]
On the other hand, according to the difference extraction method, when the tissue moves between two transmission / reception waves, the signal component (particularly the fundamental wave component) corresponding to the movement of the tissue leaks considerably after the difference calculation. That is, there is a problem that the movement is imaged without any limitation. It is rather desirable that the tissue is imaged to some extent (if the tissue is not displayed in a region where no contrast agent is present, the region cannot be identified on the image, so the tissue is displayed with low brightness, for example. The reflected wave from the tissue (especially the fundamental wave component) is very large, and if it appears as it is with high brightness on the ultrasound image as it is, it will greatly hinder the observation of the contrast agent. . This problem can be pointed out similarly whether the transmission of two ultrasonic waves is performed in the same phase relationship or in the phase inversion relationship.
[0008]
By the way, considering the case where the tissue is completely stationary in the difference extraction method described above, when two waves are transmitted in the same phase relationship, the property change occurs for the contrast agent by the first wave transmission. Therefore, the signal component corresponding to the contrast agent can be obtained in both the fundamental band and the harmonic band by the difference calculation of the two received signals. On the other hand, for the tissue, the difference between the two received signals is obtained. At the time of calculation, the signal component corresponding to the tissue is completely canceled in both the fundamental band and the harmonic band, and the problem that the tissue is not imaged can be pointed out. On the other hand, if transmission is performed twice in a phase inversion relationship, signal components can be obtained not only for the contrast agent but also for the tissue in the harmonic band (on the time axis in the positive phase and the negative phase). Since the waveform is distorted differently, there is an advantage in that sense. However, even in such a system, as described above, when the tissue is moving, the tissue is imaged without limitation. Therefore, it is possible to extract only the harmonic component from the signal after the difference calculation and to image it, but by simply imaging only the harmonic component, the part where the contrast agent is slightly present It is difficult to image contrast agents clearly.
[0009]
As described above, the conventional harmonic extraction method and differential extraction method cannot appropriately image each of the contrast agent and the tissue regardless of the movement of the living body, and therefore, a new contrast imaging method is eagerly desired. ing.
[0010]
The present invention has been made in view of the above-described conventional problems, and an object of the present invention is to enable a contrast agent to be clearly imaged and to appropriately image a living tissue.
[0011]
Another object of the present invention is to make it possible to adjust the imaging ratio of the fundamental wave component and the harmonic component according to various conditions.
[0012]
[Means for Solving the Problems]
(1) In order to achieve the above object, the present invention provides an ultrasonic diagnostic apparatus for forming an ultrasonic image by transmitting / receiving ultrasonic waves to a living body into which a contrast agent has been injected. First wave transmitting means for transmitting into the living body, and first wave receiving means for receiving the first reflected wave generated by reflecting the first ultrasonic wave in the living body and outputting the first received signal A second wave transmitting means for transmitting the second ultrasonic wave having a predetermined phase relationship with the first ultrasonic wave into the living body, and a second generated by reflecting the second ultrasonic wave in the living body. A second receiving means for receiving the reflected wave and outputting a second received signal; a signal combining means for combining the first received signal and the second received signal and outputting a combined signal; and the combined signal. Based on the above, a signal containing both components is generated in which the content ratios of the fundamental component and the harmonic component are adjusted. A minute adjustment means, characterized in that it comprises a, an image forming unit for forming an ultrasound image based on the two components containing signal.
[0013]
According to the above configuration, the first reception signal obtained by the first transmission / reception wave and the second reception signal obtained by the second transmission / reception wave are synthesized to generate a synthesis signal, and based on the synthesis signal Thus, both component-containing signals are generated, and an ultrasonic image is created by the both component-containing signals. Here, the both-component-containing signal is a signal that includes both the fundamental wave component and the harmonic component, and the content ratio of each component is fixedly adjusted or variably adjusted. Therefore, it is possible to eliminate and reduce problems that occur when only the harmonic component is imaged and when the fundamental wave component and the harmonic component are imaged as they are, and the contrast agent and the tissue can be imaged with appropriate luminance. Incidentally, it is generally desirable to increase the weighting for the harmonic component and decrease the weighting for the fundamental component. In addition, when the tissue is moving, in order to prevent the tissue from being imaged as clutter (high luminance noise), component adjustment is performed so as to remove and suppress particularly the low frequency side of the fundamental wave component. Is desirable.
[0014]
Desirably, it includes a ratio setting means for variably setting each content ratio of the fundamental component and the harmonic component in the both component-containing signal. Desirably, the said ratio setting means is a means for variably setting each content rate of the said fundamental wave component and the said harmonic component by a user. In this case, a plurality of content ratio conditions may be preset so that any one of the conditions can be selected while viewing the ultrasonic image. Desirably, the said ratio setting means is a means to variably set each content rate of the said fundamental wave component and the said harmonic component according to measurement conditions. For example, depending on the depth of the sample point (reflection point), the transmission frequency, the frequency characteristics of the ultrasonic transducer, the type of tissue, etc., the content ratio is automatically variably set (switch setting). In particular, it is desirable to variably set the content ratio according to whether or not the tissue is moving or the speed of movement of the tissue.
[0015]
(2) Moreover, in order to achieve the said objective, this invention is an ultrasonic diagnostic apparatus which transmits / receives an ultrasonic wave with respect to the biological body in which the contrast agent was inject | poured, and transmits a 1st ultrasonic wave in a biological body. First transmitting means for receiving the first reflected wave generated by reflecting the first ultrasonic wave in the living body, and outputting a first received signal; the first receiving means; A second transmission means for transmitting a second ultrasonic wave having a phase inversion relationship with the ultrasonic wave into the living body, and a second reflected wave generated by reflecting the second ultrasonic wave in the living body; A second receiving means for outputting a second received signal; a signal combining means for adding the first received signal and the second received signal to output an added combined signal; and based on the added combined signal, Component adjuster that generates both component-containing signals with adjusted proportions of fundamental and harmonic components When, characterized in that it comprises a, an image forming unit for forming an ultrasound image based on the two components containing signal.
[0016]
According to the above configuration, after the addition and synthesis of the two received signals, both the fundamental wave component and the harmonic component appear for the contrast agent (regardless of the tissue motion), and only the harmonic component appears for the tissue ( Both the fundamental component and the harmonic component appear (when there is tissue movement). In any case, if an ultrasonic image is formed using both components while adjusting the content ratio of both components, the contrast agent can be displayed clearly, taking into account not only the harmonic component but also the fundamental component. The tissue can be displayed at a certain rate, depending on its movement. Even in this case, since the fundamental wave component is not directly imaged, the tissue can be prevented from being imaged as clutter, or clutter can be greatly reduced. For example, the weight of the fundamental component may be increased when the tissue is stationary, and the signal component of the contrast agent may be taken in more. When the tissue is moving, the weight of the fundamental component is May be made smaller to give priority to the removal and suppression of clutter.
[0017]
Preferably, the component adjusting means is configured by a filter having passband characteristics corresponding to the fundamental wave component and the harmonic component. In other words, setting the passband characteristics across both the fundamental component and the harmonic component is convenient because the content ratio of both components can be adjusted at once by a single filter. Here, for example, the center frequency of the filter is set to 1.5 times the frequency of the fundamental wave or the vicinity thereof, and the passband width of the filter is excluded except for most of the second harmonics and the lower side of the fundamental wave. You may set so that an upper region part may be covered.
[0018]
Desirably, it includes a detecting means for detecting the both-component-containing signal, and the both-component-containing signal after the detection is input to the image forming means.
[0019]
Preferably, the component adjustment means includes a first filter having a first passband characteristic corresponding to at least the fundamental wave component, a second filter having a second passband characteristic corresponding to the harmonic component, and the first filter. An adder that weights and adds the first filter output signal of one filter and the second filter output signal of the second filter and outputs the both-component-containing signal.
[0020]
According to the above configuration, it is possible to easily adjust the content ratios of the fundamental wave component and the harmonic component, and in particular, it is easy to increase the weighting of the harmonic component and further enhance the contrast agent image. It is. Here, for the first filter, a passband characteristic that covers only the fundamental wave component may be set. Preferably, however, both the fundamental wave component and the harmonic component are desirably set in the same manner as the above-described filter. It is desirable to set the passband characteristics to cover.
[0021]
Preferably, the adder includes first detection means for detecting the first filter output signal and second detection means for detecting the second filter output signal. The first filter output signal and the second filter output signal after the detection are input.
[0022]
(3) Moreover, in order to achieve the said objective, this invention is an ultrasonic diagnostic apparatus which transmits / receives an ultrasonic wave with respect to the biological body in which the contrast agent was inject | poured, and transmits a 1st ultrasonic wave in a biological body. First transmitting means for receiving the first reflected wave generated by reflecting the first ultrasonic wave in the living body, and outputting a first received signal; the first receiving means; A second transmitting means for transmitting a second ultrasonic wave having the same phase relationship with the ultrasonic wave into the living body, and a second reflected wave generated by reflecting the second ultrasonic wave in the living body; , Second receiving means for outputting a second received signal, signal combining means for calculating a difference between the first received signal and the second received signal and outputting a difference synthesized signal, fundamental wave components and harmonics It has a passband characteristic corresponding to the component and inputs the differential composite signal to output the first filter output signal. A second filter that has a passband characteristic corresponding to a harmonic component, inputs the second received signal, and outputs a second filter output signal, the first filter signal, and the second filter Addition means for adding the filter signal to generate both component-containing signals in which the content ratios of the fundamental wave component and the harmonic component are adjusted, and image formation for forming an ultrasonic image based on the both component-containing signals Means.
[0023]
According to the above configuration, after the subtraction synthesis of the two received signals, both the fundamental wave component and the harmonic component appear for the contrast agent (regardless of the movement of the tissue), and for the tissue only when there is movement. Both the fundamental wave component and the harmonic wave component appear. Therefore, when an ultrasonic image is formed using only the differential composite signal, the tissue is not imaged when the tissue is stationary. However, in the above configuration, the second filter output signal is added to the differential composite signal. Therefore, the tissue can always be imaged. Here, it is possible to add the fundamental signal including the harmonic component without extracting the harmonic component from the second received signal to the differential composite signal. However, when the tissue is moving, the signal component of the tissue Therefore, it is desirable to add the second filter output signal (harmonic component) to the differential composite signal.
[0024]
Therefore, if an ultrasonic image is formed by using both components while adjusting the content ratios of both components in accordance with the above configuration, it is possible to achieve both clear display of the contrast agent and appropriate display of the tissue. It is desirable to set the same characteristics as described above for the characteristics of each filter.
[0025]
Desirably, it includes a detecting means for detecting the both-component-containing signal, and the both-component-containing signal after the detection is input to the image forming means. Preferably, the detection means includes first detection means for detecting the first filter output signal, and second detection means for detecting the second filter output signal. A later first filter output signal and a second filter output signal after the detection are input.
[0026]
(4) In order to achieve the above object, the present invention provides an ultrasonic diagnostic apparatus for forming an ultrasonic image by transmitting and receiving ultrasonic waves to a living body into which a contrast agent has been injected. A first transmitting means for transmitting a sound wave into the living body, and a first receiving means for receiving a first reflected wave generated by reflecting the first ultrasonic wave in the living body and outputting a first received signal. Generated by wave means, second wave sending means for sending the second ultrasonic wave having a predetermined phase relationship with the first ultrasonic wave into the living body, and the second ultrasonic wave reflected in the living body A second receiving means for receiving a second reflected wave and outputting a second received signal; a signal combining means for combining the first received signal and the second received signal and outputting a synthesized signal; An image forming means for forming an ultrasonic image based on the combined signal, and a front of the ultrasonic image Characterized in that it comprises a means for relatively changing the luminance distribution of the luminance distribution and biological tissue contrast agents.
[0027]
In the above configuration, the means for relatively changing the luminance distribution of the contrast agent and the luminance distribution of the living tissue is a harmonic component and a fundamental component in a signal (including a synthesized signal) used in forming an ultrasonic image. Weighting is performed.
[0028]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described with reference to the drawings.
[0029]
FIG. 1 shows a preferred embodiment of an ultrasonic diagnostic apparatus according to the present invention, and FIG. 1 is a block diagram showing the overall configuration thereof. This ultrasonic diagnostic apparatus has a function of performing the above-described contrast imaging, and FIG. 1 shows a block diagram of a configuration related thereto.
[0030]
In FIG. 1, a probe 10 is an ultrasonic probe that is used in contact with a body surface or inserted into a body cavity. An array transducer composed of a plurality of transducer elements is provided in the probe 10, and an ultrasonic beam 202 is formed by the array transducer. As is well known, the scanning surface 200 shown in FIG. 1 is formed by electronic scanning of the ultrasonic beam 202. Here, examples of the electronic scanning method include electronic linear scanning and electronic sector scanning.
[0031]
In this embodiment, in order to perform contrast imaging, a contrast agent as an ultrasonic contrast agent is injected into a living body using a syringe or the like prior to or together with ultrasonic diagnosis. The contrast agent is carried to each part of the living body along with the blood flow in the living body. For example, if a stenosis occurs in a blood vessel, the blood flow does not go sufficiently beyond the stenotic part, so the concentration of the contrast agent is extremely low in that part, so when the contrast agent is imaged. Can diagnose various diseases such as stenosis of blood vessels depending on the presence or absence of a contrast agent.
[0032]
In FIG. 1, a state in which a contrast agent 206 is injected into the blood vessel 204 is shown. Here, as described above, the contrast agent 206 is composed of a large number of microbubbles. When the contrast agent 206 is subjected to ultrasonic waves, the contrast agent 206 is vibrated or broken, and as a result, exhibits a non-linear action on the ultrasonic waves. This contrast agent itself is a known material.
[0033]
In FIG. 1, a transmission unit 12 is a circuit that supplies a transmission signal to each vibration element that constitutes the above-described array transducer, and functions as a so-called transmission beam former. The receiving unit 14 is a circuit that performs a phasing addition process on the reception signals from the respective vibration elements that constitute the array transducer described above, and functions as a so-called reception beam former. The reception signal after the phasing addition is output to the reception signal processing unit 20. The control unit 16 is configured by a CPU, a predetermined program, and the like, and performs operation control of each component in the apparatus. An operation panel 18 is connected to the control unit 16, and the control unit 16 controls the operation of the apparatus in accordance with setting conditions input using the operation panel. Incidentally, the operation panel 18 is composed of, for example, a keyboard or a trackball.
[0034]
Note that the operation panel 18 is used when the filter characteristics of various filters described later are changed by the user or when the weighting ratio in weighted addition described later is set by the user.
[0035]
The reception signal processing unit 20 is a circuit that performs reception signal processing for performing contrast imaging. A specific circuit configuration example of the reception signal processing unit 20 will be described in detail later with reference to FIGS. In any case, the reception signal processed by the reception signal processing unit 20 is output to the image forming unit 22.
[0036]
The image forming unit 22 includes, for example, a DSC (digital scan converter) and various image processing circuits. In this embodiment, a B-mode image is formed based on the reception signal output from the reception signal processing unit 20. Has been. Of course, known Doppler signal processing or the like may be performed. The image data of the ultrasonic image formed by the image forming unit 22 is output to the display device 24, and the ultrasonic image is displayed on the display screen of the display device 24. In the present embodiment, the ultrasound image is an image in which the contrast agent and the tissue are simultaneously represented as a two-dimensional tomographic image. For example, the contrast agent is displayed with high luminance, and the tissue is a low-frequency background image. Is displayed. Of course, various examples of the configuration of the ultrasonic image can be given.
[0037]
In the present embodiment, in order to perform contrast imaging, when the scanning plane 200 is formed, ultrasonic waves are transmitted and received twice in the same direction. The ultrasonic transmission repetition frequency is, for example, 4 kHz, that is, the interval between two ultrasonic transmissions in the same direction is extremely short. The control unit 16 controls transmission beam formation and reception beam formation so that the transmission unit 12 and the reception unit 14 transmit and receive two ultrasonic waves in each direction. In the present embodiment, the phase inversion mode in which the phase is inverted between the first ultrasonic transmission and the second ultrasonic transmission, and the first ultrasonic transmission and the second ultrasonic transmission. The control unit 16 controls the phase of the transmission wave in accordance with the selected mode. As the probe 10, it is desirable to use a probe having a broadband frequency characteristic that covers both the fundamental band and the harmonic (second harmonic) band.
[0038]
Next, a specific configuration example of the reception signal processing unit 20 illustrated in FIG. 1 will be described with reference to FIGS. The configuration examples shown in FIGS. 2 to 4 are circuit configuration examples when the above-described phase inversion mode is executed, and the circuits shown in FIGS. 5 and 6 are configurations when the above-described same phase mode is executed. It is an example.
[0039]
A configuration example shown in FIG. 2 will be described.
[0040]
The line memory 30 is a memory for storing a reception signal (echo data) for one ultrasonic beam. The line memory 30 stores a first reception signal obtained by the first transmission. Next, when the second ultrasonic transmission is performed, a second reception signal is obtained. The second reception signal is added to the first reception signal read from the line memory 30 and the adder 32. Additive synthesis.
[0041]
(A1) in FIG. 7 represents the spectrum of the first received signal output from the line memory 30, and (B1) in FIG. 7 represents the spectrum of the second received signal. In the spectrum shown in (A1), reference numeral 100-1 represents a fundamental wave component, and reference numeral 102-1 represents a harmonic component (second harmonic component). Similarly, in the spectrum (B1), reference numeral 100-2 indicates a fundamental wave component, and reference numeral 102-2 indicates a harmonic component. As described above, the harmonic component is generated by vibration, destruction, or non-linear action of the contrast agent, and is also generated by non-linear action of the living body. Incidentally, the harmonic component due to the contrast agent is generally larger than the harmonic component due to the living body. Comparing the harmonic component 102-1 and the harmonic component 102-2, the harmonic component 102-2 included in the second received signal is smaller, but it is constant due to the first ultrasonic wave transmission. This is because the contrast agent was destroyed at a ratio. This magnitude relationship is the same for the fundamental wave component.
[0042]
(C1) in FIG. 7 shows the spectrum of the signal output from the adder 32 shown in FIG. This spectrum is roughly composed of a fundamental wave component 104 and a harmonic component 106. When the tissue is stationary, the fundamental component 104 is caused by the contrast agent, and the harmonic component 106 is caused by both the contrast agent and the tissue. On the other hand, when the tissue is moving, the fundamental wave component 104 is generated by the contrast agent and the tissue, and the same applies to the harmonic component 106.
[0043]
In FIG. 2, a BPF (band pass filter) 34 has a filter characteristic 108 shown in FIG. 7 (D1), for example. The filter characteristic 108 can be varied by the filter characteristic setting unit 36 shown in FIG. 2, and specifically, the center frequency and the pass bandwidth can be freely set. In any case, by setting a passband that spans both the fundamental wave component and the harmonic component, and by setting filter characteristics that perform appropriate weighting for each of the fundamental wave component and the harmonic component, the contrast agent can be used. While extracting the corresponding signal components, it is possible to obtain both component-containing signals in which the signal components corresponding to the tissue are contained at a constant ratio.
[0044]
(E1) in FIG. 7 shows the spectrum 110 of the output signal from the BPF 34 described above. The spectrum after the weighting of each component is performed on the spectrum of the input signal of the BPF 34 (see (C1)). is there.
[0045]
Of course, each spectrum and filter characteristic shown in FIG. 7 are schematic for explaining the invention, and an actual spectrum or the like varies depending on measurement conditions. In any case, according to the configuration shown in FIG. 2, both components can be appropriately extracted while performing weighting by a single filter. Therefore, if the filter characteristics are variably set while viewing an ultrasonic image, for example, Image quality can be obtained.
[0046]
In particular, when the tissue is stationary, the fundamental wave component from the contrast agent can be used positively, so that the contrast agent can be clearly displayed on the ultrasonic image, and the region where the contrast agent is slightly present. Even so, it becomes possible to brightly display the contrast agent present there. By the way, if the tissue is moving, for example, if you set a filter characteristic that significantly cuts the low frequency side of the fundamental wave component, the fundamental wave component by the contrast agent is taken in while suppressing the fundamental wave component by the tissue, An image of the contrast agent can be clearly displayed. Therefore, it is desirable that the filter characteristics are automatically switched according to the movement of the tissue. In this case, for example, a known technique for detecting a motion vector between frames can be used to move the tissue.
[0047]
In FIG. 2, the reception signal (RF signal) output from the BPF 34 is input to the detection circuit 38, and detection processing is performed on the reception signal. Then, a reception signal as an envelope signal is output from the detection circuit 38 and sent to the image forming unit 22 shown in FIG.
[0048]
In the configuration example of FIG. 3, the line memory 30, the adder 32, and the detection circuit 38 are the same as those shown in FIG.
[0049]
In FIG. 3, the component adjustment unit 40 inputs the reception signal output from the adder 32, the first BPF 42 and the second BPF 44, and the addition unit 46 that performs weighted addition on the signals output from the BPFs 42 and 44. It consists of and.
[0050]
The first BPF 42 has a passband characteristic that extends over both the fundamental wave component and the harmonic component (see (E2) in FIG. 8). The second BPF 44 has passband characteristics for extracting harmonic components (see FIG. 8 (D2)). The filter characteristics of the first BPF 42 and the second BPF 44 can be changed by user setting or by automatic setting as described above.
[0051]
The adder 46 includes two multipliers 48 and 50 and an adder 52. The two multipliers 48 and 50 multiply the signals from the BPFs 42 and 44 by weighting values β and 1-β, respectively. Each signal after weighting is added by the adder 52. Here, the coefficient β can be set by a user, for example, or can be automatically variably set.
[0052]
Therefore, according to the configuration example shown in FIG. 3, the fundamental wave component and the harmonic component can be extracted while adjusting the content ratio thereof, and further, the harmonic component is added to the extracted component. It is possible to optimize the respective ratios of the signal component and the tissue signal component, and there is an advantage that the signal component can be adjusted easily or with diversity by adjusting the weighting coefficient. Incidentally, for the spectrum of the output signal of the adder 52, the one shown in FIG. Of course, each spectrum shown in FIG. 8 is merely an example, and in an actual apparatus, it varies depending on measurement conditions and the like.
[0053]
The configuration example shown in FIG. 4 is a modification of the configuration shown in FIG. 3, and in the component adjustment unit 54, detection circuits 38A and 38B are inserted between the first BPF 42 and the second BPF 44 and the addition unit 46. . That is, detection may be performed after forming a reception signal having a target spectrum, but detection processing may be performed prior to weighted addition as shown in FIG. In view of the circuit configuration, the configuration example shown in FIG. 3 seems to be more advantageous.
[0054]
Next, a configuration example in the case where the same phase mode is executed will be described with reference to FIGS. 5 and 6. In FIG. 5, the line memory 60 has the same function as the line memory 30 described above. In the differentiator 62, a difference calculation is performed on the first reception signal output from the line memory 60 and the second reception signal input separately from the first reception signal, and a difference-combined signal is output.
[0055]
(A2) in FIG. 8 shows the spectrum of the first received signal, and (B2) in FIG. 8 shows the spectrum of the second received signal. Although there is a difference between the same phase and the inverted phase, the spectrum is the same as that shown in (A1) and (B1). In (A2) and (B2), reference numerals 120-1 and 120-2 indicate fundamental wave components, and reference numerals 122-1 and 122-2 indicate harmonic components.
[0056]
FIG. 8C2 shows the spectrum of the signal output from the differentiator 62 shown in FIG. Here, reference numeral 124 indicates a fundamental wave component, and reference numeral 126 indicates a harmonic component. Here, when the tissue is stationary, the fundamental wave component 124 is generated by the contrast agent, and the harmonic component 126 is also generated by the contrast agent. On the other hand, when the tissue is moving, the fundamental wave component 124 is generated by the contrast agent and the tissue, and the same applies to the harmonic component 126.
[0057]
In FIG. 5, the component adjustment unit 64 includes a first BPF 66, a second BPF 68, and an addition unit 70, similarly to the circuit configuration example shown in FIG. Here, the output signal from the differentiator 62 is input to the first BPF 66, while the first reception signal is input to the second BPF 68.
[0058]
(E2) in FIG. 8 shows the filter characteristic 130 of the first BPF 66 shown in FIG. 5. This filter characteristic 130 is set across the fundamental wave component and the harmonic wave component. 8 (D2) shows the filter characteristic 128 of the second BPF 68 shown in FIG. 5, and the filter characteristic 128 has a passband characteristic for extracting harmonics.
[0059]
The adder 70 in FIG. 5 is composed of two multipliers 72 and 74 and an adder 76 in the same manner as the adder 46 described above, and performs weighted addition in the same manner as described above.
[0060]
8 shows the spectrum 132 of the output signal from the adder 76 shown in FIG. 5, that is, weighted addition for the signal output from the first BPF 66 and the signal output from the second BPF 68. Later results are shown.
[0061]
According to the configuration example shown in FIG. 5, according to only the signal after the difference synthesis, when the tissue is stationary, it becomes impossible to image the tissue itself, but the tissue harmonic components are actively transmitted through the second BPF 68. As a result, the tissue can be imaged. Of course, the brightness distributions of the contrast agent and the tissue image can be adjusted by adjusting the filter characteristics of the BPFs 66 and 68 and adjusting the coefficients in the above weighting.
[0062]
The signal output from the adder 76 is input to the detection circuit 38 where it is subjected to detection processing, which is the same as the configuration shown in FIG.
[0063]
The configuration example illustrated in FIG. 6 is a modification of the configuration example illustrated in FIG. 5, and detection circuits 38A and 38B are inserted between the first BPF 66 and the second BPF 68 and the weighting addition unit 70. That is, weighted addition may be performed in the state of the RF signal, or weighted addition may be performed on the signal after detection as shown in FIG.
[0064]
【The invention's effect】
As described above, according to the present invention, there is an advantage that the contrast agent can be displayed more clearly on the ultrasonic image, and the tissue can be appropriately imaged.
[Brief description of the drawings]
FIG. 1 is a block diagram showing the overall configuration of an ultrasonic diagnostic apparatus according to the present invention.
FIG. 2 is a diagram illustrating a configuration example of a signal processing unit illustrated in FIG. 1;
FIG. 3 is a diagram illustrating another configuration example of the signal processing unit illustrated in FIG. 1;
4 is a diagram illustrating another configuration example of the signal processing unit illustrated in FIG. 1. FIG.
FIG. 5 is a diagram illustrating another configuration example of the signal processing unit illustrated in FIG. 1;
6 is a diagram illustrating another configuration example of the signal processing unit illustrated in FIG. 1;
FIG. 7 is a diagram for explaining an example of signal processing in a phase inversion mode.
FIG. 8 is a diagram for explaining an example of signal processing in the same phase mode;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Probe, 12 Transmission part, 14 Reception part, 16 Control part, 20 Reception signal processing part, 22 Image formation part, 24 Display.

Claims (13)

In an ultrasonic diagnostic apparatus that forms an ultrasonic image by transmitting and receiving ultrasonic waves to a living body in which a contrast agent is injected,
First wave transmission means for transmitting the first ultrasonic wave into the living body;
First receiving means for receiving a first reflected wave generated by reflecting the first ultrasonic wave in a living body and outputting a first received signal;
A second transmission means for transmitting a second ultrasonic wave having a predetermined phase relationship with the first ultrasonic wave into the living body;
Second receiving means for receiving a second reflected wave generated by reflecting the second ultrasonic wave in the living body and outputting a second received signal;
Signal combining means for combining the first received signal and the second received signal and outputting a combined signal;
Based on the synthesized signal, component adjusting means for generating both component-containing signals in which the content ratios of the fundamental wave component and the harmonic component are adjusted;
Image forming means for forming an ultrasonic image based on the both component-containing signals;
An ultrasonic diagnostic apparatus comprising: The apparatus of claim 1.
An ultrasonic diagnostic apparatus comprising: ratio setting means for variably setting each content ratio of the fundamental wave component and the harmonic component in the both component-containing signal. The apparatus of claim 2.
The ultrasonic diagnostic apparatus, wherein the ratio setting means is a means for variably setting each content ratio of the fundamental wave component and the harmonic component by a user. The apparatus of claim 2.
The ultrasonic diagnostic apparatus, wherein the ratio setting means is a means for variably setting each content ratio of the fundamental wave component and the harmonic component according to a measurement condition. In an ultrasonic diagnostic apparatus that transmits and receives ultrasonic waves to a living body in which a contrast agent is injected,
First wave transmission means for transmitting the first ultrasonic wave into the living body;
First receiving means for receiving a first reflected wave generated by reflecting the first ultrasonic wave in a living body and outputting a first received signal;
A second transmission means for transmitting a second ultrasonic wave having a phase inversion relationship with the first ultrasonic wave into the living body;
Second receiving means for receiving a second reflected wave generated by reflecting the second ultrasonic wave in the living body and outputting a second received signal;
Signal combining means for adding the first received signal and the second received signal and outputting an added combined signal;
Component adjusting means for generating both component-containing signals in which the respective content ratios of the fundamental wave component and the harmonic component are adjusted based on the added synthesized signal;
Image forming means for forming an ultrasonic image based on the both component-containing signals;
An ultrasonic diagnostic apparatus comprising: The apparatus of claim 5.
The ultrasonic diagnostic apparatus according to claim 1, wherein the component adjustment means includes a filter having passband characteristics corresponding to the fundamental wave component and the harmonic component. The apparatus of claim 5.
Including detection means for detecting the both component-containing signals,
2. The ultrasonic diagnostic apparatus according to claim 1, wherein the signal containing both components after the detection is input to the image forming means. The apparatus of claim 5.
The component adjusting means includes
A first filter having a first passband characteristic corresponding to at least the fundamental wave component;
A second filter having a second passband characteristic corresponding to the harmonic component;
An adder that weights and adds the first filter output signal of the first filter and the second filter output signal of the second filter and outputs the both-component-containing signal;
An ultrasonic diagnostic apparatus comprising: The apparatus of claim 8.
First detection means for detecting the first filter output signal;
Second detection means for detecting the second filter output signal;
Including
The ultrasonic diagnostic apparatus according to claim 1, wherein the adder receives the first filter output signal after the detection and the second filter output signal after the detection. In an ultrasonic diagnostic apparatus that transmits and receives ultrasonic waves to a living body in which a contrast agent is injected,
First wave transmission means for transmitting the first ultrasonic wave into the living body;
First receiving means for receiving a first reflected wave generated by reflecting the first ultrasonic wave in a living body and outputting a first received signal;
A second transmitting means for transmitting a second ultrasonic wave having the same phase relationship with the first ultrasonic wave into the living body;
Second receiving means for receiving a second reflected wave generated by reflecting the second ultrasonic wave in the living body and outputting a second received signal;
Signal combining means for calculating a difference between the first received signal and the second received signal and outputting a difference combined signal;
A first filter that has a passband characteristic corresponding to a fundamental wave component and a harmonic component, inputs the differential composite signal, and outputs a first filter output signal;
A second filter having a passband characteristic corresponding to a harmonic component, inputting the second received signal and outputting a second filter output signal;
Adding means for adding the first filter signal and the second filter signal to generate both component-containing signals in which the content ratios of the fundamental wave component and the harmonic component are adjusted;
Image forming means for forming an ultrasonic image based on the both component-containing signals;
An ultrasonic diagnostic apparatus comprising: The apparatus of claim 10.
Including detection means for detecting the both component-containing signals,
2. The ultrasonic diagnostic apparatus according to claim 1, wherein the signal containing both components after the detection is input to the image forming means. The apparatus of claim 10.
First detection means for detecting the first filter output signal;
Second detection means for detecting the second filter output signal;
Including
The ultrasonic diagnostic apparatus, wherein the first filter output signal after the detection and the second filter output signal after the detection are input to the adding means. In an ultrasonic diagnostic apparatus that forms an ultrasonic image by transmitting and receiving ultrasonic waves to a living body in which a contrast agent is injected,
First wave transmission means for transmitting the first ultrasonic wave into the living body;
First receiving means for receiving a first reflected wave generated by reflecting the first ultrasonic wave in a living body and outputting a first received signal;
A second transmission means for transmitting a second ultrasonic wave having a predetermined phase relationship with the first ultrasonic wave into the living body;
Second receiving means for receiving a second reflected wave generated by reflecting the second ultrasonic wave in the living body and outputting a second received signal;
Signal combining means for combining the first received signal and the second received signal and outputting a combined signal;
Image forming means for forming an ultrasonic image based on the combined signal;
Including
An ultrasonic diagnostic apparatus comprising means for relatively changing a luminance distribution of a contrast agent and a luminance distribution of a living tissue in the ultrasonic image.

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