JP2019093253A - Ultrasonic diagnostic apparatus - Google Patents

Abstract

To provide an ultrasonic image diagnostic apparatus capable of acquiring an ultrasonic image using a harmonic component, the ultrasonic image having a wider range and more excellent distance resolution in the depth direction.SOLUTION: A transmission unit 102 outputs pulse signals whose drive waveforms differ from each other to an ultrasonic probe 103 a plurality of times at a time interval. A reception unit 104 generates a plurality of pieces of sound line information on the basis of respective reception signals obtained from reflection ultrasonic waves of transmission ultrasonic waves generated by the plurality of times of pulse signals. An operation unit 106 performs operation via a plurality of types of operation methods using the plurality of pieces of sound line information generated by the reception unit 104 to obtain respective operation results. A synthesis unit 110 synthesizes the plurality of operation results obtained by the operation unit 106.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an ultrasound diagnostic imaging apparatus.

  Ultrasonic diagnosis is a simple operation that just applies an ultrasonic probe to the body surface, and it is possible to obtain the behavior of the heart beat and the movement of the fetus in real time, and it is highly safe. be able to.

In such a technique for displaying an ultrasonic image, an image with good contrast can be obtained by imaging harmonic components (for example, frequencies 2f ₀ , 3f _0, etc.) with respect to the fundamental wave component (frequency f ₀ ) of the transmission signal. It is known to be obtained. Such an imaging method is called tissue harmonic imaging.

The above-mentioned harmonic components mainly occur due to non-linear distortion that occurs when ultrasonic waves propagate in the object. That is, the ultrasonic waves irradiated into the living body distort the signal during tissue propagation due to the non-linear response of the tissue, and the harmonic components increase. As a result, the received signal, for example, and thus to include double and frequency 2f _0, 3 times the component of the frequency 3f ₀ of the fundamental wave f _0.

  A filter method and a pulse inversion method are known as methods for extracting harmonic components in tissue harmonic imaging.

Filter method, the center frequency, for example, extracts a harmonic component of 2f ₀ from the received signal using a bandpass filter 2f _0.
On the other hand, the pulse inversion method transmits the first and second transmission pulse signals whose polarity or time is inverted at time intervals, synthesizes the respective reception signals, and cancels the fundamental wave component to generate a second harmonic. It emphasizes the wave component.

By the way, since the harmonic component contained in the ultrasonic signal has a frequency higher than that of the fundamental wave component, it is easily affected by the attenuation during propagation in the object, and the reach of the reflected ultrasonic signal from the deep part (penetration) There is a problem that is not good. On the other hand, lowering the frequency f ₀ of the fundamental wave component makes it difficult to be affected by attenuation, so that the penetration is improved but there is a trade-off that the resolution is lowered.

  Of the two methods described above, the filter method cuts the low frequency region without distinction between the fundamental wave and the harmonics, so this effect is remarkable, and the band after extraction is also narrowed, so that the image quality is also pulse. Since it is inferior to the inversion method, the pulse inversion method has become mainstream except for so-called low-end devices.

In recent years, in the above-mentioned pulse inversion method, in order to improve penetration while maintaining resolution, a method using a difference tone component lower in frequency than a second harmonic component (for example, Patent Document 1) is generated. A method is also proposed in which the harmonic component is in the frequency range of 1 to 2 times the fundamental component f ₀ (for example, Patent Document 2), and the band of the harmonic component to be received is similarly extended to improve distance resolution. It has come to be required.

  In addition, in the case of using the pulse inversion method, addition (PI (+)) and subtraction (PI (-)) are respectively performed on reception signals obtained by transmitting the first and second transmission pulse signals. There is one in which the interference of the next harmonic component is suppressed, separation extraction is performed, pulse compression is performed, and image data is generated based on these (for example, Patent Document 3).

Japanese Patent Laid-Open No. 2002-3001068 Unexamined-Japanese-Patent No. 2003-310609 JP, 2010-42048, A

  By the way, the harmonic component has the characteristic of transmission focus dependency. That is, since generation of harmonic components strongly depends on the sound pressure of the acoustic field, a good image can be obtained in the vicinity of the transmission focal point, but the resolution is lowered in a region away from this. Area was not large enough.

  On the other hand, in the inventions described in Patent Documents 1 and 2, although the distance resolution is better than the conventional narrow band harmonic imaging, the harmonic components are generated depending on the sound pressure. The area of good resolution is still limited to the vicinity of the transmission focus, etc., and the effect is still insufficient.

  In the invention described in Patent Document 3, although both PI (+) and PI (-) are used, the effect is limited to those using a contrast agent, and It can not be improved.

  An object of the present invention is to provide an ultrasonic diagnostic imaging apparatus capable of obtaining an ultrasonic image using a harmonic component excellent in distance resolution in a wider range in the depth direction.

In order to solve the above problems, the invention according to claim 1 is an ultrasonic diagnostic imaging apparatus,
An ultrasonic probe for outputting a transmission ultrasonic wave toward a subject based on the input pulse signal and outputting a reception signal by receiving a reflected ultrasonic wave from the subject;
A transmitter configured to output pulse signals of different drive waveforms to the ultrasonic probe a plurality of times at time intervals;
A receiving unit that generates a plurality of sound ray information based on each reception signal obtained from the reflected ultrasonic wave of the transmission ultrasonic wave generated by each of the plurality of pulse signals;
An operation unit that performs operations according to a plurality of types of operation methods using the plurality of pieces of sound ray information generated by the receiving unit, and obtains respective operation results;
A combining unit configured to combine a plurality of the calculation results obtained by the calculation unit;
A detection unit that detects the calculation result synthesized by the synthesis unit;
An image processing unit that generates ultrasound image data based on a result detected by the detection unit;
It is characterized by having.

The invention according to claim 2 is the ultrasonic diagnostic imaging apparatus according to claim 1.
The calculation unit is characterized by obtaining a calculation result obtained by adding the plurality of pieces of sound ray information and a calculation result obtained by subtracting the plurality of pieces of sound ray information.

The invention according to claim 3 is the ultrasonic diagnostic imaging apparatus according to claim 2.
A filter processing unit is provided that performs filter processing to cut the frequency band of the fundamental wave component included in the calculation result from the calculation result obtained by subtracting the plurality of sound ray information obtained by the calculation unit. I assume.

The invention according to claim 4 is the ultrasonic diagnostic imaging apparatus according to claim 2.
The transmission unit includes a pulse signal for power modulation that differs in amplitude only from the pulse signal of one of the plurality of pulse signals to be output in the pulse signal that is output a plurality of times, and outputs the pulse signal to the ultrasonic probe.
The arithmetic unit performs predetermined multiplication of sound ray information generated by performing phasing addition on the reception signal obtained from the reflection ultrasonic wave of the transmission ultrasonic wave generated by the power modulation pulse signal by the reception unit. Performing power modulation processing to be amplified and added to the calculation result obtained by subtracting the plurality of sound ray information;
The combining unit combines the calculation result obtained by subtracting the plurality of pieces of sound ray information after the power modulation process with the calculation result obtained by adding the plurality of pieces of sound ray information.

The invention according to claim 5 is the ultrasonic diagnostic imaging apparatus according to any one of claims 1 to 4,
The phase of the second frequency component included in the other calculation result is matched with the phase of the first frequency component included in the calculation result of one of the plurality of calculation results obtained by the calculation unit. And a phase adjusting unit for adjusting the phase of the calculation result of

The invention according to claim 6 is the ultrasonic diagnostic imaging apparatus according to claim 5.
The phase adjustment unit may change the adjustment amount of the phase of the other calculation result according to the depth.

The invention according to claim 7 is the ultrasonic diagnostic imaging apparatus according to any one of claims 1 to 6,
The transmitter includes a pulse signal whose phase is inverted from that of one of a plurality of pulse signals to be output in the pulse signal which is output a plurality of times, and outputs the pulse signal to the ultrasonic probe. I assume.

The invention according to claim 8 is the ultrasonic diagnostic imaging apparatus according to any one of claims 1 to 7,
The transmission unit transmits or receives the intensity peak of the frequency power spectrum at 1/3 or less of the upper limit frequency of the ultrasonic probe in the transmission / reception frequency band and at -20 dB of the ultrasonic probe. A pulse signal included in a frequency band equal to or higher than the lower limit frequency of the frequency band is output.

The invention according to claim 9 is the ultrasonic diagnostic imaging apparatus according to any one of claims 1 to 8,
The transmitting unit is a pulse whose intensity peak of the frequency power spectrum is included in the lower frequency side than the central frequency of the -20 dB transmission frequency band of the ultrasonic probe and in the higher frequency side than the central frequency. It is characterized by outputting a signal.

The invention according to claim 10 is the ultrasonic diagnostic imaging apparatus according to claim 9.
The transmitter is characterized in that it outputs a pulse signal in which two or more intensity peaks of the frequency power spectrum are included on a higher frequency side than a central frequency of a -20 dB transmission frequency band of the ultrasonic probe.

The invention according to claim 11 is the ultrasonic diagnostic imaging apparatus according to claim 9.
The transmission unit has at least one local minimum in the transmission / reception frequency band of the ultrasonic probe in the frequency power spectrum intensity, and the local minimum and the ultrasonic probe It is characterized in that a pulse signal of a drive waveform whose difference from the maximum intensity in the transmission / reception frequency band of 6 dB is within 10 dB is output by a three-value control signal.

The invention according to claim 12 is the ultrasonic diagnostic imaging apparatus according to any one of claims 1 to 11,
The pulse signal may be output by a control signal having five or less values.

The invention according to claim 13 is the ultrasonic diagnostic imaging apparatus according to any one of claims 1 to 12,
The ultrasonic probe is characterized in that a relative band of -20 dB is 100% or more.

The invention according to claim 14 is the ultrasonic diagnostic imaging apparatus according to claim 13.
The ultrasonic probe is characterized in that a relative band of -6 dB is 100% or more.

  According to the present invention, it is possible to obtain an ultrasonic image using a harmonic component excellent in distance resolution in a wider range in the depth direction.

FIG. 1 is a block diagram showing a schematic configuration of an ultrasound diagnostic imaging apparatus according to a first embodiment. It is a figure which shows the frequency power spectrum of transmission ultrasound. It is a figure explaining extraction of a harmonic component to which pulse inversion by addition is applied. It is a figure explaining extraction of a harmonic component to which pulse inversion by subtraction is applied. It is a figure explaining the result of the synthesis | combination of sound ray information by a synthetic | combination part. It is a figure which shows the frequency power spectrum of the transmission ultrasonic wave in 2nd Embodiment. It is a figure explaining extraction of a harmonic component to which pulse inversion by addition is applied. It is a figure explaining extraction of a harmonic component to which pulse inversion by subtraction is applied. It is a figure explaining distribution of a frequency ingredient contained in sound ray information after combination. It is a figure explaining the result of the synthesis | combination of sound ray information by a synthetic | combination part. It is a figure which shows the frequency power spectrum of the transmission ultrasonic wave in 3rd Embodiment. It is a figure explaining extraction of a harmonic component to which pulse inversion by addition is applied. It is a figure explaining extraction of a harmonic component to which pulse inversion by subtraction is applied. It is a figure explaining distribution of a frequency ingredient contained in sound ray information after combination. It is a figure explaining the result of the synthesis | combination of sound ray information by a synthetic | combination part. It is a figure which shows the frequency power spectrum of the transmission ultrasonic wave in 4th Embodiment. It is a figure explaining extraction of a harmonic component to which pulse inversion by addition is applied. It is a figure explaining extraction of a frequency ingredient to which pulse inversion by subtraction is applied. It is a figure explaining the distribution of the frequency component contained in each sound ray information. It is a figure explaining adjustment of the phase of sound ray information. It is a figure explaining the result of the synthesis | combination of sound ray information by a synthetic | combination part. It is a block diagram which shows schematic structure of the ultrasound diagnostic imaging apparatus in 5th Embodiment. It is a figure which shows the frequency power spectrum of the transmission ultrasonic wave in 5th Embodiment. It is a figure explaining extraction of a harmonic component to which pulse inversion by addition is applied. It is a figure explaining extraction of a harmonic component to which power modulation processing is applied. It is a figure explaining distribution of a frequency ingredient contained in sound ray information after combination. It is a figure explaining the result of the synthesis | combination of sound ray information by a synthetic | combination part. It is a figure explaining the transmission zone of an ultrasound probe. It is a figure explaining the drive waveform of a pulse signal, and a frequency analysis result. It is a figure explaining the drive waveform of a pulse signal, and a frequency analysis result. It is a figure explaining the drive waveform of a pulse signal, and a frequency analysis result. It is a figure explaining the drive waveform of a pulse signal, and a frequency analysis result.

  Hereinafter, an ultrasound diagnostic imaging apparatus according to an embodiment of the present invention will be described with reference to the drawings. However, the scope of the invention is not limited to the illustrated example. In the following description, components having the same function and configuration are denoted by the same reference numerals, and the description thereof is omitted.

First Embodiment
As shown in FIG. 1, the ultrasound diagnostic imaging apparatus 100 according to the first embodiment includes a first transmission waveform memory 101a, a second transmission waveform memory 101b, a transmission unit 102, an ultrasound probe 103, and a reception unit. 104, first received signal memory 105a, second received signal memory 105b, operation unit 106, BPF (Band Pass Filter) 107, BPF 108, phase adjustment unit 109, combining unit 110, detection unit 111, image processing unit 112, display unit 113 is provided.
The ultrasonic diagnostic imaging apparatus 100 is configured as described above, transmits ultrasonic waves (transmission ultrasonic waves) to a subject such as a living body (not shown), and reflects the reflected waves of the ultrasonic waves reflected by the subject. (Reflected ultrasound: echo) is received, and the internal state inside the subject is imaged as an ultrasound image based on a received signal generated from the received reflected ultrasound.

The first transmission waveform memory 101a stores the pattern of the pulse signal output from the transmission unit 102 at the first wave. In the present embodiment, for example, a pattern for generating a pulse signal by a rectangular wave composed of five values (+ HV / + MV / 0 / -MV / -HV) is used. The shape of the pattern of the pulse signal can be set arbitrarily. The pulse signal is not limited to a rectangular wave, and may have an arbitrary waveform. In addition, although a pattern in which the voltage of five values is switched to output a pulse signal is not limited to five values and can be set to an appropriate value, but five values or less are preferable. As a result, the degree of freedom in control of frequency components can be improved at low cost, and transmission ultrasonic waves with higher resolution can be obtained.
The second transmission waveform memory 101 b stores the pattern of the pulse signal output from the transmission unit 102 at the second wave. In the present embodiment, a pattern whose phase is reversed to that of the pulse signal stored in the first transmission waveform memory 101a is used. Although the pattern of the pulse signal stored in the transmission waveform memory 101b is symmetrical in polarity to the pattern of the pulse signal stored in the first transmission waveform memory 101a, it may not be completely symmetrical. For example, It may not be symmetrical with respect to some waveforms. Moreover, it may be symmetrical on the time axis.

The transmission unit 102 is a circuit that supplies a drive signal, which is an electrical signal, to the ultrasound probe 103 via a cable (not shown) and causes the ultrasound probe 103 to generate transmission ultrasound. Also, the transmission unit 102 includes, for example, a clock generation circuit, a delay circuit, and a pulse generation circuit. The clock generation circuit is a circuit that generates a clock signal that determines the transmission timing and transmission frequency of the drive signal. The delay circuit sets the transmission timing of the drive signal to a delay time for each individual path corresponding to each transducer, delays transmission of the drive signal by the set delay time, and forms a transmission beam composed of transmission ultrasonic waves. It is a circuit for focusing. The pulse generation circuit is a circuit for generating a pulse signal as a drive signal at a predetermined cycle. The transmitting unit 102 configured as described above drives, for example, continuous portions (for example, 64) of the plurality of (for example, 192) transducers arranged in the ultrasound probe 103. Transmission ultrasonic waves are generated. Then, the transmission unit 102 performs scanning (scanning) while moving the scanning line by shifting the transducer to be driven in the azimuth direction each time the transmission ultrasonic wave is generated.
In the present embodiment, the transmission unit 102 performs ultrasonic probe on a drive signal which is a pulse signal of a rectangular wave according to the pattern of the pulse signal stored in the first transmission waveform memory 101a as the first wave. Send to child 103. After that, the transmitting unit 102 ultrasonicates the drive signal which is a pulse signal by a rectangular wave according to the pattern of the pulse signal stored in the second transmission waveform memory 101b on the same scanning line at predetermined time intervals. Transmit to probe 103. That is, the transmitting unit 102 outputs pulse signals of different drive waveforms to the ultrasound probe 103 a plurality of times on the same scanning line at time intervals.

  The ultrasound probe 103 includes transducers (not shown) formed of piezoelectric elements, and a plurality of transducers are, for example, arranged in a one-dimensional array in the azimuth direction. In the present embodiment, for example, an ultrasonic probe 103 provided with 192 transducers is used. The ultrasound probe 103 converts the drive signal from the transmission unit 102 into transmission ultrasound by the transducer, receives the reflection ultrasound from inside the object, and converts it into a reception signal that is an electrical signal by the transducer. It is converted and output to the receiving unit 104. The transducers may be arranged in a two-dimensional array. Also, the number of transducers can be set arbitrarily. Further, in the present embodiment, a linear scanning electronic scan probe is adopted for the ultrasound probe 103, but either an electronic scanning method or a mechanical scanning method may be adopted, and a linear scanning method, Either a sector scan method or a convex scan method can be employed. Moreover, in the present embodiment, it is highly effective to apply an ultrasonic probe capable of performing transmission of ultrasonic waves in a wide band with good sensitivity in order to obtain high-resolution transmission ultrasonic waves. It is possible to acquire good quality ultrasound images. The bandwidth in the ultrasonic probe may be set arbitrarily, but it is preferable that the -20 dB fractional band is 100% or more, and more preferably the -6 dB fractional band is 100% or more.

The receiving unit 104 is a circuit that receives a reception signal of an electrical signal from the ultrasound probe 103 via a cable. The receiving unit 104 includes, for example, an amplifier, an A / D conversion circuit, and a phasing addition circuit. The amplifier is a circuit for amplifying the reception signal at a predetermined amplification factor set in advance for each individual path corresponding to each vibrator. The A / D conversion circuit is a circuit for analog-digital conversion (A / D conversion) of the amplified reception signal. The phasing addition circuit gives a delay time to the A / D converted received signal for each individual path corresponding to each vibrator, adjusts the time phase, adds them (phasing addition), and transmits the sound ray. It is a circuit for generating information.
In the present embodiment, the receiving unit 104 transmits the sound ray information obtained by transmitting and receiving the first wave ultrasonic wave to the first received signal memory 105 a as described above, and the second wave ultrasonic wave The sound ray information obtained by the transmission and reception of the above is transmitted to the second received signal memory 105b. That is, the receiving unit 104 receives the reception signal output from the ultrasound probe 103, and receives each reception signal obtained from the reflection ultrasound of the transmission ultrasound generated respectively by a plurality of pulse signals. A plurality of sound ray information is generated by phasing addition.

The first received signal memory 105 a temporarily stores the sound ray information obtained by the transmission and reception of the first wave ultrasonic wave by the receiving unit 104, and the sound ray information is calculated when the calculation unit 106 performs the calculation. Output.
The second received signal memory 105 b temporarily stores the sound ray information obtained by the transmission and reception of the ultrasonic wave of the second wave by the receiving unit 104, and the sound ray information is calculated when the calculation unit 106 performs the calculation. Output.

The arithmetic unit 106 is configured to include an addition processing unit 106 a and a subtraction processing unit 106 b.
The addition processing unit 106 a performs arithmetic processing by adding the sound ray information output from the first received signal memory 105 a and the sound ray information output from the second received signal memory 105 b. That is, the addition processing unit 106a performs pulse inversion (PI (+)) by addition. Thereby, the first generation harmonic component can be extracted from the sound ray information obtained from the first wave ultrasonic wave and the sound ray information obtained from the second wave ultrasonic wave. The first generation harmonic component is a harmonic component generated by distortion of the fundamental component due to sound pressure, and includes even harmonics and difference tones. The harmonic components extracted here are dominated by the second harmonic component and the difference tone component depending on the band of the ultrasonic probe 103.
The subtraction processing unit 106 b performs arithmetic processing by subtracting the sound ray information output from the first received signal memory 105 a and the sound ray information output from the second received signal memory 105 b. That is, the subtraction processing unit 106 b performs pulse inversion (PI (−)) by subtraction. Thereby, the fundamental wave component and the second generation harmonic component are extracted from the sound ray information obtained from the first wave ultrasonic wave and the sound ray information obtained from the second wave ultrasonic wave it can. The second generation harmonic component is a harmonic component in which a first generation harmonic component such as a second harmonic generated from a fundamental component is generated by the influence of the fundamental component, and includes, for example, a third harmonic .
The addition processing unit 106 a outputs the result of the arithmetic processing to the BPF 107, and the subtraction processing unit 106 b outputs the result of the arithmetic processing to the BPF 108.
As described above, the arithmetic unit 106 performs arithmetic operations according to plural types of arithmetic methods using the plurality of pieces of sound ray information generated by the receiving unit 104, and obtains respective arithmetic results.

The BPF 107 is a band pass filter for removing noise components from the calculation result of the addition processing unit 106a. The BPF 107 outputs the filtered sound ray information to the combining unit 110.
The BPF 108 is a band pass filter for cutting the fundamental wave component from the calculation result of the subtraction processing unit 106 b and extracting only the second generation harmonic component. The BPF 108 outputs the filtered sound ray information to the phase adjustment unit 109.

The phase adjustment unit 109 adjusts the phase so that the phase of the second generation harmonic component included in the sound ray information filtered by the BPF 108 is emphasized to the positive polarity side. That is, the phase adjustment unit 109 determines the phase of the first generation harmonic component included in the sound ray information obtained as a result of performing the pulse inversion (PI (+)) by adding the phase of the second generation harmonic component. Adjust the phase to match. Various methods can be employed to adjust the phase. For example, the simplest method is sign inversion. That is, by multiplying the input sound ray information by the coefficient (-1), the phase can be rotated 180 degrees without filtering the output sound ray information. In addition, an all-pass digital filter having phase rotation characteristics other than 180 degrees can be configured by appropriately controlling a transfer function such as an FIR (Finite Impulse Response) filter. In addition, all pass filter and IIR (Infinite Impulse Response)
The cutoff characteristics and the order of a filter having no linear phase, such as a filter, may be designed as appropriate, and the desired frequency range may be rotated by a predetermined amount with filtering. The phase adjustment unit 109 outputs the sound ray information whose phase has been adjusted to the combining unit 110. The phase adjustment unit 109 may not be provided.

  The combining unit 110 performs combining processing by adding the sound ray information output from the BPF 107 and the sound ray information output from the phase adjusting unit 109. That is, the combining unit 110 combines a plurality of calculation results obtained by the calculation unit 106. By performing this combining process, the combining unit 110 can obtain sound ray information in which the fundamental wave component is cut and the first generation harmonic component and the second generation harmonic component are included. The synthesis unit 110 outputs the sound ray information subjected to the synthesis process to the detection unit 111. In addition, weighting may be performed at the time of combining processing.

  The detection unit 111 performs envelope detection on the sound ray information output from the combining unit 110, acquires envelope data, and outputs the envelope data to the image processing unit 112.

  The image processing unit 112 performs logarithmic amplification, gain adjustment, and the like on the envelope data output from the detection unit 111, performs amplitude luminance conversion, and generates B-mode image data. That is, B-mode image data represents the intensity of the received signal by luminance. The image processing unit 112 holds the generated B-mode image data in the memory in units of frames, reads it out at appropriate timing, and outputs it to the display unit 113. Thus, the image processing unit 112 generates ultrasound image data based on the result detected by the detection unit 111.

  The display unit 113 is applicable to a display device such as a liquid crystal display (LCD), a cathode-ray tube (CRT) display, an organic EL (Electronic Luminescence) display, an inorganic EL display, a plasma display, and the like. The display unit 113 displays an ultrasound image on the display screen based on the image data output from the image processing unit 112.

  Next, a method of extracting harmonic components by the ultrasound diagnostic imaging apparatus 100 configured as described above will be described.

First, as a transmission ultrasonic wave to be output to the first wave th outputs an ultrasonic wave having a fundamental component f ₁ showing the frequency power spectrum as shown in FIG. 2 (a), the reflected ultrasonic wave of the transmitted ultrasonic wave Sound ray information is obtained from the obtained received signal and stored in the first received signal memory 105a. This transmission ultrasonic wave has an intensity peak in the transmission / reception frequency band P of the ultrasonic probe 103 and is 1/3 or less of the upper limit frequency (FH) in the transmission / reception frequency band of -20 dB and the ultrasonic probe It is a narrow-band ultrasonic wave included in a frequency band equal to or higher than the lower limit frequency (FH) of the transmission / reception frequency band at 103 -20 dB. Thereafter, as the transmission ultrasonic wave to be output to the second wave th as shown in FIG. 2 (b), the first wave-th output an ultrasonic wave having a fundamental component f ₁ showing a frequency power spectrum is phase reversed The sound ray information is obtained from the received signal obtained from the reflected ultrasonic wave of the transmitted ultrasonic wave, and is stored in the second received signal memory 105b.

Subsequently, the sound ray information stored in the first received signal memory 105 a and the sound ray information stored in the second received signal memory 105 b are input to the addition processing unit 106 a of the arithmetic unit 106, and pulse inversion by addition ( Perform PI (+). As a result, sound ray information indicating a frequency power spectrum as shown in FIG. 3A is obtained. That is, the addition processing section 106a, 2 harmonic sound ray information component 2f ₁ is emphasized as a first-generation harmonic component is obtained. Since this sound ray information contains a noise component as shown in FIG. 3A, as shown in FIG. 3B, the noise component is removed by the BPF 107 and the second harmonic component 2f is removed. Filter processing using a band pass filter such that only ₁ is extracted. Then, as shown in FIG. 3C, the noise component is removed and sound ray information in which only the second harmonic component 2f ₁ is extracted is obtained.

Also, pulse inversion (PI) is input by inputting the sound ray information stored in the first received signal memory 105 a and the sound ray information stored in the second received signal memory 105 b into the subtraction processing unit 106 b of the arithmetic unit 106. Do (-)). As a result, sound ray information indicating a frequency power spectrum as shown in FIG. 4A is obtained. That is, the subtraction processing unit 106b, 3-order harmonic component 3f ₁ and has emphasized sound ray information as a basic wave component f ₁ and the second-generation harmonic component is obtained. Then, in order to remove the fundamental wave component f ₁ and the noise component from the sound ray information, as shown in FIG. 4B, the BPF 108 cuts the fundamental wave component f ₁ and the noise component to generate the third harmonic component A filtering process is performed using a band pass filter such that only 3f ₁ is extracted. Then, as shown in FIG. 4 (c), only the third harmonic component 3f ₁ and the fundamental component f ₁ and the noise component is removed is sound ray information extracted is obtained. In the present embodiment, a band pass filter that cuts only the third harmonic component 3f ₁ to cut the fundamental wave component f ₁ and the noise component is used, but a band limitation that cuts only the fundamental wave component f ₁ is used. A filter may be used. Thereafter, the phase adjustment unit 109 adjusts the phase of the sound ray information after filter processing, and the phase of the third harmonic component 3f ₁ is emphasized to the positive polarity side as shown in FIG. 4D. Let's do it.

Thus, the sound ray information obtained by the calculation by the addition processing unit 106a as shown in FIG. 5A and the sound obtained by the calculation by the subtraction processing unit 106b as shown in FIG. 5B. The line information is added and combined by the combining unit 110. Then, as shown in FIG. 5 (c), sound ray data which the secondary harmonic component 2f ₁ and the third harmonic component 3f ₁ has broadband it is synthesized is obtained. As a result, since the distance resolution is improved, a good ultrasonic image can be obtained. In addition, the second generation harmonic component included in sound ray information obtained by pulse inversion (PI (−)) by subtraction of sound ray information is pulse inversion (PI (+)) by addition of sound ray information. An ultrasonic beam that is more dependent on sound pressure in generation than the first generation harmonic component contained in the acquired sound ray information and thinner than the first generation harmonic component is obtained, and sound ray information including these harmonic components The azimuth resolution can be improved by combining

Second Embodiment
Next, a second embodiment of the present invention will be described. The basic configuration of the ultrasound diagnostic imaging apparatus 100 in the second embodiment is the same as that of the first embodiment, and thus the description thereof is omitted here.

In the second embodiment, as the transmission ultrasonic wave to be output to the first wave th outputs an ultrasonic wave having a fundamental component f ₁ showing the frequency power spectrum as shown in FIG. 6 (a), the transmission than Sound ray information is obtained from the received signal obtained from the reflected ultrasonic wave of the sound wave and stored in the first received signal memory 105a. This transmission ultrasonic wave is a broad band ultrasonic wave with respect to the transmission / reception frequency band P of the ultrasonic probe 103. Thereafter, as the transmission ultrasonic wave to be output to the second wave th as shown in FIG. 6 (b), the first wave-th output an ultrasonic wave having a fundamental component f ₁ showing a frequency power spectrum is phase reversed The sound ray information is obtained from the received signal obtained from the reflected ultrasonic wave of the transmitted ultrasonic wave, and is stored in the second received signal memory 105b.

Subsequently, the sound ray information stored in the first received signal memory 105 a and the sound ray information stored in the second received signal memory 105 b are input to the addition processing unit 106 a of the arithmetic unit 106, and pulse inversion by addition ( Perform PI (+). As a result, sound ray information indicating a frequency power spectrum as shown in FIG. 7A is obtained. That is, the addition processing section 106a, 2 harmonic sound ray information component 2f ₁ is emphasized as a first-generation harmonic component is obtained. Since this sound ray information contains a noise component as shown in FIG. 7A, as shown in FIG. 7B, the noise component is removed by the BPF 107 and the second harmonic component 2f is removed. Filter processing using a band pass filter such that only ₁ is extracted. Then, as shown in FIG. 7 (c), the sound ray information noise component is removed only second harmonic component 2f ₁ is extracted is obtained.

Also, pulse inversion (PI) is input by inputting the sound ray information stored in the first received signal memory 105 a and the sound ray information stored in the second received signal memory 105 b into the subtraction processing unit 106 b of the arithmetic unit 106. Do (-)). As a result, sound ray information indicating a frequency power spectrum as shown in FIG. 8A is obtained. That is, the subtraction processing unit 106b, 3-order harmonic component 3f ₁ and has emphasized sound ray information as a basic wave component f ₁ and the second-generation harmonic component is obtained. Then, in order to remove the fundamental wave component f ₁ and the noise component from the sound ray information, as shown in FIG. 8B, the BPF 108 cuts the fundamental wave component f ₁ and the noise component to generate the third harmonic component A filtering process is performed using a band pass filter such that only 3f ₁ is extracted. Then, as shown in FIG. 8 (c), only the third harmonic component 3f ₁ and the fundamental component f ₁ and the noise component is removed is sound ray information extracted is obtained. Then, the phase adjustment unit 109 performs adjustment of the phase with respect to the sound ray information after filtering, Figure 8 phase second harmonic component 2f ₁ of the third harmonic component 3f ₁ as shown in (d) of (Addition result) As the same phase, combining is performed without cancellation at the time of synthesis.

Thus, the sound ray information obtained by the calculation by the addition processing unit 106 a and the sound ray information obtained by the calculation by the subtraction processing unit 106 b are added and synthesized by the synthesis unit 110. FIG. 9 shows the relationship between the depth and the intensity of each harmonic component included in the sound ray information after combination. As shown in FIG. 9, since the sound pressure is the largest in the vicinity of the depth a, which is the transmission focus, the intensity of the second harmonic component 2f ₁ peaks. And, in yet deep, it generated second harmonic component 2f ₁ increases the third harmonic intensity components 3f ₁ under the influence of the fundamental wave component, the intensity has a peak in the vicinity of the depth b.

Therefore, as shown in FIG. 10A, sound ray information in which the second harmonic component 2f ₁ is dominant is obtained at depth a in FIG. 9, and as shown in FIG. 10B at depth b. In addition, sound ray information with large intensity of the third harmonic component 3f ₁ can be obtained. As a result, the wide-band receivable area is expanded in the depth direction, and an ultrasonic image having a wide range in the depth direction and excellent distance resolution can be obtained. In addition, the second generation harmonic component included in sound ray information obtained by pulse inversion (PI (−)) by subtraction is included in sound ray information obtained by pulse inversion (PI (+)) by addition. An ultrasonic beam is generated that has higher sound pressure dependency than the first generation harmonic components and is narrower than the first generation harmonic components, and the azimuth resolution can be obtained by synthesizing sound ray information including these harmonic components. It can be improved.

Third Embodiment
Next, a third embodiment of the present invention will be described. The basic configuration of the ultrasound diagnostic imaging apparatus 100 according to the third embodiment is the same as that of the first embodiment, and thus the description thereof is omitted here.

In the third embodiment, as shown in FIG. 11A, an ultrasonic wave having two fundamental wave components f ₁ and f ₂ different in frequency is output as the transmission ultrasonic wave to be output to the first wave. The sound ray information is obtained from the reception signal obtained from the reflection ultrasonic wave of the transmission ultrasonic wave, and is stored in the first reception signal memory 105a. After that, as a transmission ultrasonic wave to be output to the second wave, a supersonic wave having fundamental wave components f ₁ and f ₂ indicating a frequency power spectrum whose phase is inverted to that of the first wave as shown in FIG. A sound wave is output, sound ray information is obtained from the reception signal obtained from the reflected ultrasonic wave of the transmission ultrasonic wave, and stored in the second reception signal memory 105b.

Subsequently, the sound ray information stored in the first received signal memory 105 a and the sound ray information stored in the second received signal memory 105 b are input to the addition processing unit 106 a of the arithmetic unit 106, and pulse inversion by addition ( Perform PI (+). As a result, sound ray information indicating a frequency power spectrum as shown in FIG. 12A is obtained. That is, the addition processing unit 106a, difference frequency component [f the second harmonic component 2f ₁ and the fundamental wave component f ₂ and the fundamental wave component f ₁ of the first generation harmonic components generated from the fundamental wave component f ₁ Sound ray information in which ₂ −f ₁ ] is emphasized is obtained. Since this sound ray information contains a noise component as shown in FIG. 12A, as shown in FIG. 12B, the noise component is removed by the BPF 107 and the second harmonic component 2f is removed. A filter process is performed using a band pass filter such that ₁ and a difference tone component [f ₂ −f ₁ ] is extracted. Then, as shown in FIG. 12C, the noise component is removed, and sound ray information in which only the _second harmonic component 2f ₁ and the difference tone component [f ₂ −f ₁ ] are extracted is obtained.

Also, pulse inversion (PI) is input by inputting the sound ray information stored in the first received signal memory 105 a and the sound ray information stored in the second received signal memory 105 b into the subtraction processing unit 106 b of the arithmetic unit 106. Do (-)). As a result, sound ray information indicating a frequency power spectrum as shown in FIG. 13 (a) is obtained. That is, sound ray information in which the fundamental wave components f ₁ and f ₂ and the second generation harmonic component [3f ₁ + {(f ₂ −f ₁ ) + f ₂ }] are emphasized can be obtained by the subtraction processing unit 106 b. . Then, in order to remove the fundamental wave components f ₁ and f ₂ and the noise component from the sound ray information, as shown in FIG. 13B, the BPF 108 cuts the fundamental wave components f ₁ and f ₂ and the noise component. A filter process using a band pass filter is performed so that only the second generation harmonic component [3f ₁ + {(f ₂ −f ₁ ) + f ₂ }] is extracted. Then, as shown in FIG. 13C, the fundamental wave components f1 and f2 and noise components are removed, and only the second generation harmonic component [3f ₁ + {(f ₂ −f ₁ ) + f ₂ }] is extracted. The obtained sound ray information is obtained. Thereafter, the phase adjustment unit 109 adjusts the phase of the sound ray information after the filter processing, and the second generation harmonic component [3f ₁ + {(f ₂ −f ₁ ) as shown in FIG. As in the second embodiment, the phase of + f ₂ }] is combined with the result of addition as the same phase, without being canceled at the time of synthesis.

Thus, the sound ray information obtained by the calculation by the addition processing unit 106 a and the sound ray information obtained by the calculation by the subtraction processing unit 106 b are added and synthesized by the synthesis unit 110. FIG. 14 shows the relationship between the depth and the intensity of each harmonic component included in the sound ray information after combination. As shown in FIG. 14, the difference tone component [f ₂ −f ₁ ] is dominant in the shallow portion of the transmission focus f than the depth a, and then the second harmonic component 2f ₁ is dominant in the depth a It becomes. Then, further in the deep part, the generated second harmonic component 2f ₁ and the difference tone component [f ₂ −f ₁ ] are affected by the fundamental component and the second generation harmonic component [3f ₁ + {(f ₂₎ The intensity of −f ₁ ) + f ₂ }] increases, and the intensity peaks near the depth b.

Therefore, the depth a in FIG. 14, FIG. 15 (a), the harmonic component second-order harmonic component 2f ₁ and difference frequency component _[f 2 -f _1] is dominant _{[(f 2} - Wide-band sound ray information including f ₁ ) + 2f ₁ + [3f ₁ + {(f ₂ −f ₁ ) + f ₂ }]] is obtained, and at depth b, as shown in FIG. A harmonic whose intensity of the second-generation harmonic component [3f ₁ + {(f ₂ -f ₁ ) + f ₂ }] is large because the intensities of the harmonic component 2f ₁ and the difference tone component [f ₂ -f ₁ ] are reduced. Broadband sound ray information including the component [(f ₂ −f ₁ ) + 2f ₁ + [3 f ₁ + {(f ₂ −f ₁ ) + f ₂ }]] is obtained. As a result, the wide-band receivable area is expanded in the depth direction, and an ultrasonic image having a wide range in the depth direction and excellent distance resolution can be obtained. In addition, the second generation harmonic component included in sound ray information obtained by pulse inversion (PI (−)) by subtraction is included in sound ray information obtained by pulse inversion (PI (+)) by addition. An ultrasonic beam is generated that has higher sound pressure dependency than the first generation harmonic components and is narrower than the first generation harmonic components, and the azimuth resolution can be obtained by synthesizing sound ray information including these harmonic components. It can be improved.

Fourth Embodiment
Next, a fourth embodiment of the present invention will be described. The basic configuration of the ultrasound diagnostic imaging apparatus 100 in the fourth embodiment is the same as that of the first embodiment, and thus the description thereof is omitted here.

In the fourth embodiment, as shown in FIG. 16A, an ultrasonic wave having three fundamental wave components f ₁ , f ₂ and f ₃ different in frequency as transmission ultrasonic waves to be output to the first wave. And the sound ray information is obtained from the reception signal obtained from the reflected ultrasonic wave of the transmission ultrasonic wave, and is stored in the first reception signal memory 105a. After that, as transmission ultrasonic waves to be output to the second wave, fundamental wave components f ₁ , f ₂ , and f _{3 as shown in FIG.} Is output, sound ray information is obtained from the received signal obtained from the reflected ultrasonic wave of the transmitted ultrasonic wave, and stored in the second received signal memory 105b.

Subsequently, the sound ray information stored in the first received signal memory 105 a and the sound ray information stored in the second received signal memory 105 b are input to the addition processing unit 106 a of the arithmetic unit 106, and pulse inversion by addition ( Perform PI (+). As a result, sound ray information indicating a frequency power spectrum as shown in FIG. 17A is obtained. That is, by the addition processing unit 106 a, the first generation harmonic component [(f ₃ −f ₂ ) + (f ₂ −f ₁ )], [2f ₁ + (f ₃ −f ₁ )], and [f ₁ + f ₂ The sound ray information emphasized can be obtained. Since this sound ray information contains a noise component as shown in FIG. 17A, as shown in FIG. 17B, the noise component is removed by the BPF 107 and the first generation harmonic component is removed. Filter processing using a band pass filter such that Then, as shown in FIG. 17C, the noise component is removed and the first generation harmonic component [(f ₃ −f ₂ ) + (f ₂ −f ₁ )], [2f ₁ + (f ₃ −) Sound ray information in which only f ₁ )] and [f ₁ + f ₂ ] are extracted is obtained.

Also, pulse inversion (PI) is input by inputting the sound ray information stored in the first received signal memory 105 a and the sound ray information stored in the second received signal memory 105 b into the subtraction processing unit 106 b of the arithmetic unit 106. Do (-)). As a result, sound ray information indicating a frequency power spectrum as shown in FIG. 18A is obtained. That is, the subtraction processing unit 106b, the fundamental wave component f ₁ and the second-generation harmonic component alpha ₁ and is synthesized frequency component, is a fundamental component f ₂ and the second-generation harmonic component alpha ₂ was synthesized frequency component, and the fundamental wave component f ₃ and the sound ray information frequency component and a second-generation harmonic component alpha ₃ is synthesized is emphasized is obtained. Here, the second generation harmonic components α ₁ , α ₂ and α ₃ are respectively constituted by harmonic components represented by the following formulas (1) to (3).
α ₁ = (2 f ₁ −f ₁ ) + {(f ₃ −f ₁ ) −f ₁ } + (f ₃ −2 f ₁ ) + {f ₃ − (f ₃ −f ₁ )} + {f ₂ − ( f ₃ −f ₂ )} + {f ₂ − (f ₂ −f ₁ )} + {(f ₁ + f ₂ ) −f ₂ } (1)
α ₂ = {(f ₁ + f ₂ ) -f ₁ } + (f ₃ −2f ₁ ) + {f ₃ − (f ₃ −f ₁ )} (2)
α ₃ = 3f ₁ + {f ₂ + (f ₂ −f ₁ )} + {f ₂ + (f ₃ −f ₂ )} + {f ₁ + (f ₃ −f ₁ )} (3)

Then, a frequency component in which the fundamental wave component f ₁ and the second generation harmonic component α ₁ are synthesized from the sound ray information, and a frequency component in which the fundamental wave component f ₂ and the second generation harmonic component α ₂ are synthesized , and, for removing a noise component, as shown in FIG. 18 (b), by BPF108, fundamental component _{f 1} and the second-generation harmonic component alpha ₁ and is synthesized frequency components, the fundamental wave component _{f 2} And a band pass filter such that only the fundamental wave component f ₃ and the second generation harmonic component α ₃ are extracted by cutting the noise component and the frequency component in which the second generation harmonic component α ₂ and the second generation harmonic component α ₂ are combined. Perform the filtering process used. Then, as shown in FIG. 18 (c), the fundamental wave component f ₁ and the second-generation harmonic component alpha ₁ and is synthesized frequency component, is a fundamental component f ₂ and the second-generation harmonic component alpha ₂ synthesized frequency component, and, sound ray information noise component is removed only the fundamental wave component f ₃ and second generation harmonic component alpha ₃ is extracted is obtained.

FIG. 19 shows the relationship between the depth and the intensity of the frequency component included in the sound ray information obtained as described above. As shown in FIG. 19, in the shallow region, small amount of generated harmonic components, a dominant fundamental component f _3, in the vicinity of a depth a, the intensity of the fundamental wave component f ₃ reaches a peak. After that, as the depth increases, the intensity of the fundamental wave component f ₃ decreases until the depth E, and the first generation harmonic component [(f ₃ −f ₂ ) + (f ₂ −f ₁ )], [ The strengths of f ₁ + f ₂ ] and [2f ₁ + (f ₃ −f ₁ )] increase. The second-generation harmonic component alpha ₃ is, the amount is small. Then, in the deeper than the depth E, the intensity of the second-generation harmonic component alpha ₃ first generation harmonic component occurred under the influence of the fundamental wave component is gradually increased. Thereafter, in the vicinity of the depth b, the intensity of the first generation harmonic component peaks. Thereafter, the intensity of the first-generation harmonic component is reduced, the intensity of the second-generation harmonic component alpha ₃ is further increased, the intensity of the second-generation harmonic component alpha ₃ has a peak in the vicinity of the depth c.

In this embodiment, since each frequency component has the characteristics as described above, the subtraction processing unit 106 b after filter processing is performed so that sound ray information including frequency components with high resolution can be efficiently obtained. When the phase adjustment is performed on the sound ray information obtained by the calculation, the phase adjustment amount is changed according to the depth.
That is, in the region from the shallowest portion to the depth E, the phase adjustment unit 109 adds the phase of the fundamental wave component f ₃ to the addition result as in the second embodiment, as shown in FIG. As the same phase, phase adjustment (phase adjustment A) to be combined at the time of synthesis is performed. On the other hand, in the region deeper than the depth E, as shown in FIG. 20B, the phase adjustment unit 109 has the same phase as the addition result of the second generation harmonic component α ₃ as in the second embodiment. As the phase adjustment (phase adjustment B), coupling is performed without cancellation at the time of synthesis.

  Thus, the sound ray information obtained by the calculation by the subtraction processing unit 106 b after the filter processing is adjusted in phase according to the depth, and the sound ray information obtained by the calculation by the addition processing unit 106 a It is additively synthesized by 110.

As a result, at depth a in FIG. 19, as described above, sound ray information whose phase adjustment has been performed such that the phase of the fundamental wave component f ₃ is emphasized to the positive polarity side is synthesized. As shown in a), the first generation harmonic component [(f ₃ −f ₂ ) + (f ₂ −f ₁ )], [f ₁ + f ₂ ], [2f ₁ + (f ₃ −f ₁ )] less, sound ray data of wideband fundamental component f ₃ is dominant can be obtained. Therefore, high frequency fundamental wave components can be used in the shallow region, and S / N and distance resolution in the shallow region can be improved.
Further, at depth b and depth c in FIG. 19, since the sound ray information on which the phase adjustment is performed such that the second generation harmonic component α ₃ is emphasized on the positive polarity side is synthesized as described above, At the depth b, as shown in FIG. 21B, the second generation harmonic component α ₃ is small, and the first generation harmonic component [(f ₃ −f ₂ ) + (f ₂ −f ₁ )], [ As shown in FIG. 21C, a wide band sound ray information in which f ₁ + f ₂ ] and [2f ₁ + (f ₃ −f ₁ )] are dominant is obtained, and as shown in FIG. As the intensity of the wave component [f ₁ + f ₂ ] decreases, the first generation harmonic component [(f ₃ −f ₂ ) + (f ₂ −f ₁ )], [2f ₁ + (f ₃ −f ₁ )] And second-generation harmonic component α ₃ is dominant, broadband acoustic ray information is obtained. As a result, the wide-band receivable area is expanded in the depth direction, and an ultrasonic image having a wide range in the depth direction and excellent distance resolution can be obtained. In addition, the second generation harmonic component included in sound ray information obtained by pulse inversion (PI (−)) by subtraction is included in sound ray information obtained by pulse inversion (PI (+)) by addition. An ultrasonic beam is generated that has higher sound pressure dependency than the first generation harmonic components and is narrower than the first generation harmonic components, and the azimuth resolution can be obtained by synthesizing sound ray information including these harmonic components. It can be improved.

Fifth Embodiment
Next, a fifth embodiment of the present invention will be described. The ultrasound diagnostic imaging apparatus 100A in the fifth embodiment is the first embodiment in that the third transmission waveform memory 101c and the third reception signal memory 105c are added, and the arithmetic unit 106A and the BPF 108A are modified. Is different from the ultrasonic diagnostic imaging apparatus 100 in FIG. Here, only the points different from the ultrasound diagnostic imaging apparatus 100 in the first embodiment will be described, and the same configurations will be denoted by the same reference numerals and descriptions thereof will be omitted.

  The third transmission waveform memory 101c stores the pattern of the pulse signal output from the transmission unit 102 at the third wave. In the present embodiment, a pattern of a pulse signal for power modulation that differs only in amplitude from the pulse signal stored in the first transmission waveform memory 101a is used. The pattern of the pulse signal stored in the third transmission waveform memory 101c is, for example, an amplitude of 1/4 of the pattern of the pulse signal stored in the first transmission waveform memory 101a, but is arbitrarily set. can do. The ultrasonic wave output based on the pattern of the pulse signal stored in the third transmission waveform memory 101c has a small amplitude, so that it is difficult for harmonic components to be generated.

  The third reception signal memory 105c temporarily stores the sound ray information obtained by the transmission and reception of the third wave ultrasonic wave by the receiving unit 104, and the sound ray information is calculated when the calculation unit 106A performs the calculation. Output.

  The arithmetic unit 106A includes an AMP 106c and a power modulation processing unit 106d in addition to the addition processing unit 106a and the subtraction processing unit 106b.

  The AMP 106 c receives the sound ray information output from the third reception signal memory 105 c, amplifies the sound ray information by a predetermined factor, and outputs the amplified sound ray to the power modulation processing unit 106 d. In the present embodiment, for example, the AMP 106 c receives the sound ray information output from the third reception signal memory 105 c and amplifies it by eight times.

  The power modulation processing unit 106d performs arithmetic processing (power modulation processing) by additively combining sound ray information, which is the calculation result of the subtraction processing unit 106b, and sound ray information amplified by the AMP 106c. The sound ray information output from the third received signal memory 105 c and amplified by the AMP 106 c is dominant in the fundamental wave component and contains almost no harmonic component. Therefore, the power modulation process is performed to perform subtraction processing unit 106 b. It is possible to efficiently extract the second generation harmonic component by cutting only the fundamental wave component from the sound ray information generated by the above. The power modulation processing unit 106d outputs sound ray information obtained as a result of performing the arithmetic processing as described above to the BPF 108A.

  The BPF 108A is a band pass filter for removing noise components from the calculation result of the power modulation processing unit 106d. The BPF 108A outputs the filtered sound ray information to the phase adjustment unit 109.

  Next, a method of extracting harmonic components by the ultrasound diagnostic imaging apparatus 100A configured as described above will be described.

In the fifth embodiment, as shown in FIG. 23A, an ultrasonic wave having three fundamental wave components f ₁ , f ₂ and f ₃ different in frequency as transmission ultrasonic waves to be output to the first wave. And the sound ray information is obtained from the reception signal obtained from the reflected ultrasonic wave of the transmission ultrasonic wave, and is stored in the first reception signal memory 105a. After that, as transmission ultrasonic waves to be output to the second wave, fundamental wave components f ₁ , f ₂ , and f _{3 as shown in FIG.} Is output, sound ray information is obtained from the received signal obtained from the reflected ultrasonic wave of the transmitted ultrasonic wave, and stored in the second received signal memory 105b. After that, as a transmission ultrasonic wave to be output to the third wave, an ultrasonic wave having an amplitude of 1⁄4 of the ultrasonic wave output to the first wave as shown in FIG. Sound ray information is obtained from a received signal obtained from the reflected ultrasonic wave, and is stored in the third received signal memory 105c.

Subsequently, the sound ray information stored in the first received signal memory 105 a and the sound ray information stored in the second received signal memory 105 b are input to the addition processing unit 106 a of the arithmetic unit 106, and pulse inversion by addition ( Perform PI (+). As a result, sound ray information indicating a frequency power spectrum as shown in FIG. 24A is obtained. That is, by the addition processing unit 106 a, the first generation harmonic component [(f ₃ −f ₂ ) + (f ₂ −f ₁ )], [2f ₁ + (f ₃ −f ₁ )], and [f ₁ + f ₂ The sound ray information emphasized can be obtained. Since this sound ray information contains a noise component as shown in FIG. 24A, as shown in FIG. 24B, the noise component is removed by the BPF 107 and the first generation harmonic component is removed. Filter processing using a band pass filter such that Then, as shown in FIG. 24C, the noise component is removed and the first generation harmonic component [(f ₃ −f ₂ ) + (f ₂ −f ₁ )], [2f ₁ + (f ₃ −) Sound ray information in which only f ₁ )] and [f ₁ + f ₂ ] are extracted is obtained.

Also, pulse inversion (PI) is input by inputting the sound ray information stored in the first received signal memory 105 a and the sound ray information stored in the second received signal memory 105 b into the subtraction processing unit 106 b of the arithmetic unit 106. Do (-)). As a result, sound ray information indicating a frequency power spectrum as shown in FIG. 25 (a) is obtained. That is, the subtraction processing unit 106b, the fundamental wave component f ₁ and the second-generation harmonic component alpha ₁ and is synthesized frequency component, is a fundamental component f ₂ and the second-generation harmonic component alpha ₂ was synthesized frequency component, and the fundamental wave component f ₃ and the sound ray information frequency component and a second-generation harmonic component alpha ₃ is synthesized is emphasized is obtained. The second generation harmonic components α ₁ , α ₂ and α ₃ are respectively constituted by the harmonic components represented by the above formulas (1) to (3).

  Further, the sound ray information stored in the third received signal memory 105c is input to the AMP 106c of the calculation unit 106 to amplify the sound ray information by a factor of 8, and a sound showing a frequency power spectrum as shown in FIG. Get line information.

Subsequently, in order to remove the fundamental wave components f ₁ , f ₂ and f ₃ from the sound ray information obtained by the pulse inversion (PI (−)), the power modulation processing unit 106 d performs pulse inversion (PI (− ) And the sound ray information amplified by the AMP 106 c are added and synthesized to perform power modulation processing. Then, as shown in FIG. 25 (c), the fundamental wave components f ₁ , f ₂ and f ₃ are removed and the sound ray information in which only the second generation harmonic components α ₁ , α ₂ and α ₃ are extracted is can get.

Then, in order to remove the noise component from the sound ray information, as shown in FIG. 25C, a band pass filter is used in which the noise component is removed by the BPF 108A and the second generation harmonic component is extracted. Filter it. Then, as shown in FIG. 25D, sound ray information in which only noise components are removed and only the second generation harmonic components α ₁ , α ₂ and α ₃ are extracted is obtained. Thereafter, the phase adjustment unit 109 adjusts the phase of the sound ray information after the filter processing, and the phases of the second generation harmonic components α ₁ , α ₂ and α ₃ are adjusted as shown in FIG. As in the second embodiment, as the addition result and the same phase, combining is performed without cancellation at the time of synthesis.

Thus, the sound ray information obtained by the calculation by the addition processing unit 106 a and the sound ray information obtained by the power modulation process are added and synthesized by the synthesizing unit 110. FIG. 26 shows the relationship between the depth and the intensity of each harmonic component included in the sound ray information after combination. As shown in FIG. 26, at the depth a which is shallower than the depth b which is the transmission focus, the first generation harmonic component [(f ₃ −f ₂ ) + (f ₂ −f ₁ )], [f ₁ + f ₂ ] and [2 f ₁ + (f _3- f ₁ )] are dominant. Thereafter, as the depth increases, the first generation harmonic components [(f ₃ −f ₂ ) + (f ₂ −f ₁ )], [f ₁ + f ₂ ], and [2f ₁ + (f ₃ −f ₁ )] In addition, the intensity of the second generation harmonic components α ₁ , α ₂ and α ₃ also increases, and the first generation harmonic component [(f ₃ −f ₂ ) + (f ₂ −f ₁ )] near the depth b , [F ₁ + f ₂ ] and [2f ₁ + (f ₃ −f ₁ )] have peaks. After that, as the depth increases, the intensity of the first generation harmonic component gradually decreases and the second generation harmonic component increases, and the second generation harmonic components α ₁ , α ₂ , α ₃ near the depth c The peak intensity of After that, the second generation harmonic component becomes dominant in the deep part of the depth c.

Therefore, as shown in FIG. 27A, at the depth a in FIG. 26, the second generation harmonic components α ₁ , α ₂ , and α ₃ are small, and the first generation harmonic component [(f ₃ −f ₂ ) Wide-band sound ray information in which + (f ₂ −f ₁ )], [f ₁ + f ₂ ] and [2f ₁ + (f ₃ −f ₁ )] are dominant is obtained. Therefore, in the shallow region, the S / N can be improved while maintaining the distance resolution. Also, at depth b, as shown in FIG. 27 (b), the first generation harmonic component [(f ₃ −f ₂ ) + (f ₂ −f ₁ )], [f ₁ + f ₂ ], [2 f ₁ As shown in FIG. 27C, a wide band sound ray information is obtained in which the intensities of + (f ₃ −f ₁ )] and the second generation harmonic components α ₁ , α ₂ and α ₃ are respectively increased. As shown, while the second generation harmonic components α ₁ , α ₂ and α ₃ become larger, the broadband sound ray information in which the intensity of the first generation harmonic component [f ₁ + f ₂ ] becomes smaller is obtained. Be Therefore, a wide band receivable region can be expanded in the depth direction, an ultrasonic image excellent in distance resolution in a wide range in the depth direction can be obtained, and the S / N can be improved. Further, at the depth d, as shown in FIG. 27D, sound ray information in which the second generation harmonic components α ₁ and α ₂ are dominant can be obtained. Therefore, in the deep region, the sound ray information can be obtained by the low frequency harmonic component, and the S / N is improved to be a wide band, so that penetration and distance resolution in the deep region can be improved. In addition, the second generation harmonic component included in sound ray information obtained by pulse inversion (PI (−)) by subtraction is included in sound ray information obtained by pulse inversion (PI (+)) by addition. An ultrasonic beam is generated that has higher sound pressure dependency than the first generation harmonic components and is narrower than the first generation harmonic components, and the azimuth resolution can be obtained by synthesizing sound ray information including these harmonic components. It can be improved.

  Hereinafter, the present invention will be described in more detail by way of examples, but of course the present invention is not limited to these examples.

Example 1
First, as the ultrasonic probe 103 described above, the lower limit frequency (FL6) at transmission / reception -6 dB is 5.0 MHz, the upper limit frequency (FH6) is 15.0 MHz, the center frequency (FC6) is 10.0 MHz, transmission / reception -6 dB The relative bandwidth is 100%, the lower limit frequency (FL20) at transmission / reception -20 dB is 3.9 MHz, the upper limit frequency (FH20) is 18.1 MHz, the center frequency (FC20) is 11.0 MHz, and the transmission / reception -20 dB relative bandwidth is 129 The lower limit frequency (FL20) at transmission -20 dB is 3.4 MHz, the upper limit frequency (FH20) is 21.2 MHz, the center frequency (FC20) is 12.3 MHz, and the relative bandwidth of transmission and reception -20 dB is 145%. An ultrasonic probe was used as an ultrasonic probe A. The transmission band shape of the ultrasonic probe A is shown by A in FIG. In FIG. 28, the horizontal axis represents frequency and the vertical axis represents sensitivity.

  The pulse signal of the first wave output from the transmission unit 102 described above is a drive waveform as shown in FIG. 29A, and this is a drive waveform 1. The frequency power spectrum obtained by frequency analysis of the drive waveform 1 is shown in FIG. In FIG. 29A, the horizontal axis indicates time, and the vertical axis indicates voltage. Further, in FIG. 29B, the horizontal axis indicates the frequency, and the vertical axis indicates the signal strength. The transmission ultrasonic wave output by the pulse signal of this drive waveform 1 has one intensity peak in the transmission frequency band (3.4 MHz-21.2 MHz) at -20 dB of the above-mentioned ultrasonic probe A. The peak was lower than the center frequency (FC20) at the transmission of -20 dB of the ultrasonic probe A, and the frequency at the peak was 6.3 MHz. The pulse signal of the second wave is a drive waveform obtained by inverting the phase of the drive waveform 1.

  Pulse inversion by addition using sound ray information obtained by transmitting and receiving ultrasonic waves by the pulse signal of the first wave and sound ray information obtained by transmitting and receiving ultrasonic waves by the pulse signal of the second wave (PI (+)) and pulse inversion by subtraction (PI (-)) were respectively performed. Then, with respect to the sound ray information obtained by the pulse inversion (PI (+)) by the addition, the filter processing by the band pass filter which passes the band of 8 MHz to 14 MHz is performed. And after performing the filter processing by the band pass filter which makes the zone of 11 MHz-20 MHz pass with respect to the sound ray information obtained by the pulse inversion (PI (-)) by subtraction, the phase adjustment by the all pass filter was performed . After that, additive synthesis is performed on sound ray information obtained by pulse inversion (PI (−)) by subtraction subjected to phase adjustment and sound ray information obtained by pulse inversion (PI (+)) by addition. did.

(Comparative example 1)
Example except that pulse inversion (PI (−)) by subtraction is not performed, and ultrasonic image data is generated using only sound ray information obtained by pulse inversion (PI (+)) by addition Same as 1.

(Example 2)
First, as the above-mentioned ultrasound probe 103, the above-mentioned ultrasound probe A was used.

  The pulse signal of the first wave output from the transmission unit 102 described above is set as a drive waveform as shown in FIG. The frequency power spectrum obtained by frequency analysis of the drive waveform 2 is shown in FIG. In FIG. 30A, the horizontal axis indicates time, and the vertical axis indicates voltage. Further, in FIG. 30 (b), the horizontal axis indicates the frequency, and the vertical axis indicates the signal strength. The transmission ultrasonic wave outputted by the pulse signal of this drive waveform 2 has one intensity peak in the transmission frequency band (3.4 MHz-21.2 MHz) at -20 dB of the above-mentioned ultrasonic probe A. The peak was lower than the center frequency (FC20) at the transmission of -20 dB of the ultrasonic probe A, and the frequency at the peak was 8.1 MHz. The pulse signal of the second wave is a drive waveform obtained by inverting the phase of the drive waveform 2.

  Pulse inversion by addition using sound ray information obtained by transmitting and receiving ultrasonic waves by the pulse signal of the first wave and sound ray information obtained by transmitting and receiving ultrasonic waves by the pulse signal of the second wave (PI (+)) and pulse inversion by subtraction (PI (-)) were respectively performed. Then, with respect to the sound ray information obtained by the pulse inversion (PI (+)) by the addition, the filter processing by the band pass filter which passes the band of 8 MHz to 20 MHz is performed. And after performing the filter processing by the band pass filter which makes the zone of 11 MHz-20 MHz pass with respect to the sound ray information obtained by the pulse inversion (PI (-)) by subtraction, the phase adjustment by the all pass filter was performed . After that, additive synthesis is performed on sound ray information obtained by pulse inversion (PI (−)) by subtraction subjected to phase adjustment and sound ray information obtained by pulse inversion (PI (+)) by addition. did.

(Comparative example 2)
Example except that pulse inversion (PI (−)) by subtraction is not performed, and ultrasonic image data is generated using only sound ray information obtained by pulse inversion (PI (+)) by addition Same as 2.

(Example 3)
First, as the above-mentioned ultrasound probe 103, the above-mentioned ultrasound probe A was used.

  The pulse signal of the first wave output from the transmission unit 102 described above is set as a drive waveform as shown in FIG. The frequency power spectrum obtained by frequency analysis of this drive waveform 3 is shown in FIG. In FIG. 31A, the horizontal axis represents time, and the vertical axis represents voltage. Further, in FIG. 31 (b), the horizontal axis indicates the frequency, and the vertical axis indicates the signal strength. The transmission ultrasonic wave output by the pulse signal of this drive waveform 3 has two intensity peaks in the transmission frequency band (3.4 MHz-21.2 MHz) at -20 dB of the above-mentioned ultrasonic probe A. The peaks were respectively on the high frequency side and the low frequency side of the center frequency (FC 20) at the transmission of -20 dB of the ultrasonic probe A, and the frequencies at the peaks were 11.5 MHz and 7.0 MHz. The pulse signal of this drive waveform 3 has an intensity of the frequency power spectrum of the ultrasonic wave output from the ultrasonic probe A at least 1 within the transmission and reception frequency band of -6 dB of the ultrasonic probe A. It is a pulse signal of a three-value drive waveform that has one minimum value and a difference between this minimum value and the maximum intensity within the -6 dB transmission / reception frequency band of the ultrasonic probe A is within 10 dB. The pulse signal of the second wave is a drive waveform obtained by inverting the phase of the drive waveform 3.

  Pulse inversion by addition using sound ray information obtained by transmitting and receiving ultrasonic waves by the pulse signal of the first wave and sound ray information obtained by transmitting and receiving ultrasonic waves by the pulse signal of the second wave (PI (+)) and pulse inversion by subtraction (PI (-)) were respectively performed. Then, with respect to the sound ray information obtained by the pulse inversion (PI (+)) by the addition, the filter processing by the band pass filter which passes the band of 4 MHz to 20 MHz is performed. Then, the sound ray information obtained by the pulse inversion (PI (−)) by subtraction is subjected to filter processing by a band pass filter that passes a band of 13 MHz to 20 MHz, and then phase adjustment by an all pass filter is performed. . After that, additive synthesis is performed on sound ray information obtained by pulse inversion (PI (−)) by subtraction subjected to phase adjustment and sound ray information obtained by pulse inversion (PI (+)) by addition. did.

(Comparative example 3)
Example except that pulse inversion (PI (−)) by subtraction is not performed, and ultrasonic image data is generated using only sound ray information obtained by pulse inversion (PI (+)) by addition Same as 3.

(Example 4)
First, as the above-mentioned ultrasound probe 103, the above-mentioned ultrasound probe A was used.

  The pulse signal of the first wave output from the transmission unit 102 described above is set as a drive waveform as shown in FIG. The frequency power spectrum obtained by frequency analysis of the drive waveform 4 is shown in FIG. In FIG. 32A, the horizontal axis indicates time, and the vertical axis indicates voltage. Further, in FIG. 32B, the horizontal axis indicates the frequency, and the vertical axis indicates the signal strength. The transmission ultrasonic wave output by the pulse signal of this drive waveform 4 has three intensity peaks in the transmission frequency band (3.4 MHz-21.2 MHz) at -20 dB of the above-mentioned ultrasonic probe A. There are two peaks on the high frequency side and one on the low frequency side of the center frequency (FC20) at the transmission -20 dB of the ultrasonic probe A, and the frequency at the peak is 19.2 MHz and 13.2 MHz. And 5.8 MHz. The pulse signal of the second wave is a drive waveform obtained by inverting the phase of the drive waveform 4.

  Pulse inversion by addition using sound ray information obtained by transmitting and receiving ultrasonic waves by the pulse signal of the first wave and sound ray information obtained by transmitting and receiving ultrasonic waves by the pulse signal of the second wave (PI (+)) and pulse inversion by subtraction (PI (-)) were respectively performed. Then, with respect to the sound ray information obtained by the pulse inversion (PI (+)) by the addition, the filter processing by the band pass filter which passes the band of 4 MHz to 20 MHz is performed. Then, the sound ray information obtained by the pulse inversion (PI (−)) by subtraction is subjected to filter processing by a band pass filter that passes a band of 13 MHz to 20 MHz, and then phase adjustment by an all pass filter is performed. . After that, additive synthesis is performed on sound ray information obtained by pulse inversion (PI (−)) by subtraction subjected to phase adjustment and sound ray information obtained by pulse inversion (PI (+)) by addition. did.

(Comparative example 4)
Example except that pulse inversion (PI (−)) by subtraction is not performed, and ultrasonic image data is generated using only sound ray information obtained by pulse inversion (PI (+)) by addition Same as 4.

(Example 5)
When performing phase adjustment on sound ray information obtained by pulse inversion (PI (−)) by subtraction, the phase of the fundamental wave component is on the positive polarity side in the region from the shallowest portion to the depth of 10 mm. The same adjustment as in Example 4 was carried out except that the phase adjustment to be emphasized was performed, and the phase adjustment was performed such that harmonic components were emphasized on the positive polarity side in a region deeper than 10 mm in depth.

(Example 6)
First, as the above-mentioned ultrasound probe 103, the above-mentioned ultrasound probe A was used.

  The pulse signal of the first wave output from the transmitting unit 102 described above is the drive waveform 4 described above, and the pulse signal of the second wave is the drive waveform obtained by inverting the phase of the drive waveform 4, and the third wave The pulse signal of (1) is a drive waveform having an amplitude of 1⁄4 of the drive waveform 4.

  Pulse inversion by addition using sound ray information obtained by transmitting and receiving ultrasonic waves by the pulse signal of the first wave and sound ray information obtained by transmitting and receiving ultrasonic waves by the pulse signal of the second wave (PI (+)) and pulse inversion by subtraction (PI (-)) were respectively performed. Then, the sound ray information obtained by transmission and reception of the ultrasonic wave by the pulse signal of the third wave is amplified eight times, and additively synthesized with the sound ray information obtained by pulse inversion (PI (−)) by subtraction. Power modulation processing was performed. Then, with respect to the sound ray information obtained by the pulse inversion (PI (+)) by the addition, the filter processing by the band pass filter which passes the band of 4 MHz to 20 MHz is performed. Then, the sound ray information obtained by the power modulation process is subjected to filter processing by a band pass filter that passes a band of 4 MHz to 20 MHz, and then phase adjustment by an all pass filter is performed. After that, sound ray information obtained by the power modulation processing subjected to the phase adjustment and sound ray information obtained by pulse inversion (PI (+)) by addition are added and synthesized.

(Example 7)
First, as the ultrasonic probe 103 described above, the lower limit frequency (FL6) at transmission and reception -6 dB is 5.9 MHz, the upper limit frequency (FH6) is 14.2 MHz, the center frequency (FC6) is 10.0 MHz and transmission and reception -6 dB The relative bandwidth is 83%, the lower limit frequency (FL20) at transmission and reception -20 dB is 5.2 MHz, the upper limit frequency (FH20) is 16.7 MHz, the center frequency (FC20) is 11.0 MHz, and the relative bandwidth at transmission and reception -20 dB is 105 The upper limit frequency (FL20) at transmission -20 dB is 4.9 MHz, the upper limit frequency (FH20) is 19.7 MHz, the center frequency (FC20) is 12.3 MHz, and the relative band of transmission and reception -20 dB is 120%. An ultrasonic probe was used as an ultrasonic probe B. The transmission band shape of the ultrasonic probe B is shown by B in FIG.

  The drive waveform of the pulse signal of the first wave output from the transmission unit 102 described above is referred to as a drive waveform 4. The transmission ultrasonic wave output by the pulse signal of this drive waveform 4 has three intensity peaks in the transmission frequency band (4.9 MHz-19.7 MHz) at -20 dB of the above-mentioned ultrasonic probe B. There are two peaks on the high frequency side and one on the low frequency side of the center frequency (FC 20) at the transmission -20 dB of the ultrasonic probe B, and the frequency at the peak is 19.0 MHz and 13.1 MHz. And 6.0 MHz. The pulse signal of the second wave is a drive waveform obtained by inverting the phase of the drive waveform 4.

  Pulse inversion by addition using sound ray information obtained by transmitting and receiving ultrasonic waves by the pulse signal of the first wave and sound ray information obtained by transmitting and receiving ultrasonic waves by the pulse signal of the second wave (PI (+)) and pulse inversion by subtraction (PI (-)) were respectively performed. Then, with respect to the sound ray information obtained by the pulse inversion (PI (+)) by the addition, the filter processing by the band pass filter which passes the band of 5 MHz to 19 MHz was performed. Then, the sound ray information obtained by the pulse inversion (PI (−)) by subtraction is subjected to filter processing by a band pass filter that passes a band of 13 MHz to 19 MHz, and then phase adjustment by an all pass filter is performed. . Here, when adjusting the phase of the sound ray information obtained by the pulse inversion (PI (−)) by subtraction, the phase of the fundamental wave component is positive in the region from the shallowest portion to the depth of 10 mm. The phase was adjusted so as to be emphasized on the sex side, and the phase was adjusted so that harmonic components were emphasized on the positive side in a region deeper than 10 mm in depth. After that, additive synthesis is performed on sound ray information obtained by pulse inversion (PI (−)) by subtraction subjected to phase adjustment and sound ray information obtained by pulse inversion (PI (+)) by addition. did.

(Comparative example 5)
Example except that pulse inversion (PI (−)) by subtraction is not performed, and ultrasonic image data is generated using only sound ray information obtained by pulse inversion (PI (+)) by addition Same as 7.

(Example 8)
First, as the ultrasonic probe 103 described above, the lower limit frequency (FL6) at transmission and reception -6 dB is 6.2 MHz, the upper limit frequency (FH6) is 13.8 MHz, the center frequency (FC6) is 10.0 MHz and transmission and reception -6 dB The relative bandwidth is 76%, the lower limit frequency (FL20) at 5.7dB for transmission and reception-20dB, the upper limit frequency (FH20) for 16.0MHz, the center frequency (FC20) for 10.9MHz, and the relative bandwidth for transmission and reception-20dB is 95 The lower limit frequency (FL20) at transmission -20 dB is 5.6 MHz, the upper limit frequency (FH20) is 19.1 MHz, the center frequency (FC20) is 12.3 MHz, and the transmission and reception -20 dB relative band is 109%. An ultrasonic probe C was used as an ultrasonic probe. The transmission band shape of the ultrasonic probe C is indicated by C in FIG.

  The drive waveform of the pulse signal of the first wave output from the transmission unit 102 described above is referred to as a drive waveform 4. The transmission ultrasonic wave output by the pulse signal of this drive waveform 4 has two intensity peaks in the transmission frequency band (5.6 MHz-19.1 MHz) at -20 dB of the above-mentioned ultrasonic probe C. The peaks were respectively on the high frequency side and the low frequency side of the center frequency (FC 20) at the transmission of -20 dB of the ultrasound probe C, and the frequencies at the peaks were 13.0 MHz and 6.2 MHz. The pulse signal of the second wave is a drive waveform obtained by inverting the phase of the drive waveform 4.

  Pulse inversion by addition using sound ray information obtained by transmitting and receiving ultrasonic waves by the pulse signal of the first wave and sound ray information obtained by transmitting and receiving ultrasonic waves by the pulse signal of the second wave (PI (+)) and pulse inversion by subtraction (PI (-)) were respectively performed. Then, with respect to the sound ray information obtained by the pulse inversion (PI (+)) by the addition, the filter processing by the band pass filter which passes the band of 5.5 MHz to 18 MHz is performed. Then, the sound ray information obtained by the pulse inversion (PI (−)) by subtraction is subjected to filter processing by a band pass filter that passes a band of 13 MHz to 18 MHz, and then phase adjustment by an all pass filter is performed. . Here, when adjusting the phase of the sound ray information obtained by the pulse inversion (PI (−)) by subtraction, the phase of the fundamental wave component is positive in the region from the shallowest portion to the depth of 10 mm. The phase was adjusted so as to be emphasized on the sex side, and the phase was adjusted so that harmonic components were emphasized on the positive side in a region deeper than 10 mm in depth. After that, additive synthesis is performed on sound ray information obtained by pulse inversion (PI (−)) by subtraction subjected to phase adjustment and sound ray information obtained by pulse inversion (PI (+)) by addition. did.

(Comparative example 6)
Example except that pulse inversion (PI (−)) by subtraction is not performed, and ultrasonic image data is generated using only sound ray information obtained by pulse inversion (PI (+)) by addition Same as 8.

  Each condition of each Example mentioned above and a comparative example is shown in following Table 1.

<Evaluation method>
A 50 μm SUS wire was embedded in each of the depths 7, 15, 25 and 40 mm of the same acoustic equivalent material as the RMI 404 GS-LE 0.5 manufactured by Gammex. Then, the ultrasonic waves of the first wave and the second wave (further in the sixth embodiment, the third wave) are transmitted / received with the transmission focal point of the transmission ultrasonic wave being 15 mm, and obtained from each of the received ultrasonic waves. The sound ray information was processed under the conditions shown in Table 1 above to obtain an ultrasonic image. Then, the wire drawing luminance at the time of imaging was converted into acoustic intensity (dB), and its 20 dB resolution (distance resolution, azimuth resolution) was obtained.
Also, the difference between the wire drawing luminance at the time of imaging and the background luminance at the time of transmission stop was converted to acoustic intensity (dB), and this value was set as S / N.
In addition, with respect to the acoustic equivalent material part of the RMI 403 GS-LE 0.5 manufactured by Gammex, the transmission focal point is set to 15 mm, and the first and second waves (in addition, the third wave in the sixth embodiment) Sound waves are transmitted and received, ultrasonic images of two consecutive frames are acquired, correlations between ultrasonic images of these two frames are determined, depths at which the correlation is less than 0.5, and depths ( Penetration).
In addition, under the conditions of each of Examples 1 to 8 and Comparative Examples 1 to 6, the carpal, the MP joint (MetacarpoPhalangeal joint) flexors tendon, the biceps long biceps longus tendon, and the medial meniscal are depicted, and the orthopedic Based on the evaluation criteria below, a score of 10 was obtained by a total of 10 physicians and laboratory technicians engaged in the above, and the values were averaged and used as a visualization score.
[Evaluation criteria]
10: Excellent visualization for grasping organizational condition 8: Visualization showing no problem for organizational condition 6: Visualization not good but adequate for grasping organizational condition 4 : Drawability to a certain extent with difficulty in grasping the state of organization 2: Visualization of a degree of difficulty in grasping the state of organization The above evaluation results are shown in Table 2 below.

<Evaluation result>
According to the results of Table 2, according to Examples 1 to 8, especially in comparison with Comparative Examples 1 to 6, the distance resolution and the azimuth resolution are better in the deep region than the transmission focus, and the penetration degree (Penetration) It was also found to be large. Moreover, according to Examples 1-8, compared with Comparative Examples 1-6, it turned out that the evaluation evaluation of the carpal, MP joint flexor tendon, biceps long biceps longus tendon, and the medial meniscus is high.

  As described above, according to the first to fifth embodiments, the ultrasound probe 103 outputs the transmission ultrasound toward the subject based on the input pulse signal, and Outputs a received signal by receiving the reflected ultrasonic wave from. The transmission unit 102 outputs pulse signals of different drive waveforms to the ultrasonic probe 103 plural times at time intervals. The receiving unit 104 generates a plurality of sound ray information based on each received signal obtained from the reflected ultrasonic wave of the transmitted ultrasonic wave generated respectively by the pulse signal of the plurality of times. The arithmetic unit 106 (arithmetic unit 106A) performs arithmetic operations according to plural types of arithmetic methods using the plurality of pieces of sound ray information generated by the receiving unit 104, and obtains respective arithmetic results. The combining unit 110 combines a plurality of calculation results obtained by the calculation unit 106 (calculation unit 106A). The detection unit 111 detects the calculation result synthesized by the synthesis unit 110. The image processing unit 112 generates ultrasound image data based on the result of detection by the detection unit 111. As a result, since a plurality of pieces of sound ray information having different characteristics are obtained by calculation and these calculation results are interpolatedly synthesized, an ultrasonic image using harmonic components with excellent distance resolution in a wider range in the depth direction is obtained. Can. In addition, it is possible to obtain an image with a good distance resolution by broadening the sound ray information instead of combining narrow band images. Furthermore, the azimuth resolution and penetration in the deep region can be improved.

  Further, according to the first to fifth embodiments, the calculation unit 106 (calculation unit 106A) obtains an operation result obtained by adding a plurality of sound ray information and an operation result obtained by subtracting a plurality of sound ray information. . As a result, even-order harmonics can be extracted by addition and odd-order harmonics can be extracted by subtraction, so that it is possible to obtain high distance resolution over a wider range in the depth direction by using both.

  Further, according to the first to fourth embodiments, the BPF 108 reduces the frequency band of the fundamental wave component included in the calculation result to the calculation result obtained by subtracting the plurality of sound ray information obtained by the calculation unit 106. Perform filter processing to cut As a result, higher azimuth resolution can be obtained. In addition, appropriate frequency components can be extracted with a high S / N ratio, and high quality ultrasound images can be obtained.

  Further, according to the fifth embodiment, the transmission unit 102 includes a pulse signal for power modulation, which has a different amplitude from that of one pulse signal among the plurality of pulse signals to be output, in a pulse signal that is output a plurality of times. Output to the ultrasound probe 103. Arithmetic unit 106A amplifies the sound ray information generated by phasing addition of the reception signal obtained from the reflected ultrasonic wave of the transmission ultrasonic wave generated from the pulse signal for power modulation by reception unit 104 by a predetermined factor. A power modulation process is performed to add to the calculation result obtained by subtracting plural pieces of sound ray information. The combining unit 110 combines the calculation result obtained by subtracting the plurality of pieces of sound ray information after the power modulation processing with the calculation result obtained by adding the plurality of pieces of sound ray information. As a result, by performing the power modulation process, it is possible to efficiently suppress the fundamental wave component and extract the harmonic component. In addition, since the second generation harmonic component such as the second harmonic generated due to the influence of the fundamental wave component on the first generation harmonic component is also generated in the low frequency region, using this to improve the penetration. become able to.

  Further, according to the first to fifth embodiments, the phase adjustment unit 109 is configured to set the first calculation result included in one of the plurality of calculation results obtained by the calculation unit 106 (calculation unit 106A). The phase of the other calculation result is adjusted so that the phase of the second frequency component included in the other calculation result matches the phase of the frequency component. As a result, it is possible to suppress the cancellation of signal components when synthesizing sound ray information.

  Further, according to the fourth embodiment, the phase adjustment unit 109 changes the adjustment amount of the phase of another calculation result according to the depth. As a result, by performing appropriate phase adjustment according to the depth, even if the depth changes, it is possible to obtain broad-band sound ray information, so it is possible to expand the region with good distance resolution in the depth direction Become.

  Further, according to the first to fifth embodiments, the transmitting unit 102 converts the pulse signal whose phase is inverted to that of one of the plurality of pulse signals to be output into a pulse signal that is output a plurality of times. It includes and outputs to the ultrasound probe 103. As a result, better sound ray information can be obtained.

  Further, according to the first to fifth embodiments, the transmitter 102 is configured such that the intensity peak of the frequency power spectrum is 1/3 of the upper limit frequency of the -20 dB transmission / reception frequency band of the ultrasound probe 103, And the pulse signal contained in the frequency band more than the lower limit frequency of the transmission-and-reception frequency band in -20 dB of ultrasonic probe 103 is outputted. As a result, strong transmission can be performed in a frequency range in which the third harmonic component can be acquired, and the third harmonic component can be more effectively used.

  Further, according to the third to fifth embodiments, in the transmission section 102, the intensity peak of the frequency power spectrum is lower than the center frequency of the -20 dB transmission frequency band of the ultrasound probe 103. The pulse signal included in each of the high frequency side than the center frequency is output. As a result, wide band transmission can be performed, and not only high-order harmonic components but also difference tone components can be used to receive wide-band harmonics, and distance resolution is improved.

  Further, according to the fourth and fifth embodiments, the transmission section 102 is configured such that the intensity peak of the frequency power spectrum is higher on the high frequency side than the center frequency of the -20 dB transmission frequency band of the ultrasound probe 103. The pulse signal contained above is output. As a result, higher-bandwidth harmonics can be received, and distance resolution is further improved.

  Further, according to the third embodiment, the transmission unit 102 has at least one local minimum value within the transmission / reception frequency band of the ultrasound probe 103 with the intensity of the frequency power spectrum being A pulse signal of a drive waveform is output by a ternary control signal such that the difference between the minimum value and the maximum intensity of the ultrasonic probe 103 in the -6 dB transmission / reception frequency band is within 10 dB. As a result, harmonic components can be generated better, and image quality can be improved.

  Further, according to the first to fifth embodiments, since the pulse signal is output by the control signal of five values or less, the resolution can be improved at low cost.

  Further, according to the first to fifth embodiments, since the ultrasonic probe 103 sets the relative bandwidth of −20 dB to 100% or more, higher effects can be obtained.

  Further, according to the first to fifth embodiments, since the ultrasonic probe 103 sets the relative bandwidth of −6 dB to 100% or more, it is possible to obtain a higher effect.

  The description in the embodiment of the present invention is an example of the ultrasound diagnostic imaging apparatus according to the present invention, and the present invention is not limited to this. The detailed configuration and the detailed operation of each functional unit constituting the ultrasound diagnostic imaging apparatus can be appropriately changed.

  Further, in the embodiment described above, sound ray information obtained by transmission and reception of the ultrasonic wave by the pulse signal of the first wave, and sound ray information obtained by the transmission and reception of the ultrasonic wave by the pulse signal of the second wave Are used to synthesize the results obtained by performing pulse inversion (PI (+)) by addition and pulse inversion (PI (−)) by subtraction, respectively, but the calculation method is the same as that described above. There is no limitation, and arithmetic methods other than addition and subtraction may be adopted.

  In the embodiment described above, the filter processing is performed on the result obtained by performing pulse inversion (PI (−)) by subtraction to cut the fundamental wave component, but the basic method is performed by another method. The wave component may be cut.

  Further, in the above-described embodiment, the adjustment amount of the phase is changed according to the depth, but may be constant.

  Moreover, the waveform of the drive signal given to the ultrasound probe 103 is not limited to what was mentioned above, It can set arbitrarily.

  Further, in the above-described embodiment, the drive signal by the rectangular wave is transmitted from the transmission unit 102 to the ultrasound probe 103, but the drive signal by the arbitrary waveform is applied to the ultrasound probe 103. It is also good.

100, 100A Ultrasonic diagnostic imaging apparatus 102 Transmission unit 103 Ultrasonic probe 104 Reception unit 106, 106A Calculation unit 108 BPF
109 phase adjustment unit 110 synthesis unit 111 detection unit 112 image processing unit

The present invention relates to an ultrasonic diagnostic apparatus .

An object of the present invention is to provide an ultrasonic diagnostic apparatus capable of obtaining an ultrasonic image using a harmonic component excellent in distance resolution in a wider range in the depth direction.

In order to solve the above problems, the invention according to claim 1 is an ultrasonic diagnostic apparatus ,
Based on the input driving signal and outputs the transmission ultrasound, it receives the reflected ultrasonic wave from the subject, an ultrasonic probe that outputs a reception signal,
A transmitter configured to output a drive signal to the ultrasonic probe;
A receiving unit that generates based rather sound ray information in the received signal corresponding to the reflected ultrasonic wave from the subject of the transmission ultrasound based on the drive signal,
Based on the sound ray data, and a calculation unit for extracting a harmonic component,
An image processing unit that generates ultrasound image data based on the harmonic components extracted by the calculation unit ;
And the transmission unit, the transmission ultrasonic wave, a first fundamental component f ₁ having an intensity peak at a first frequency, the second having an intensity peak at a second frequency higher than said first frequency the fundamental wave component f _2, the second to include a third fundamental component f ₃ having an intensity peak at a higher third frequency than the frequency, and outputs the driving signal,
The ratio of the first frequency, the second frequency and the third frequency may be about 1: 2: 3 .

The invention according to claim 2 is the ultrasonic diagnostic apparatus according to claim 1.
The arithmetic unit, the first second harmonic of the fundamental wave component f _1, the first fundamental wave component f ₁ and the second chord component of the fundamental wave component f _2, and the first, second A difference tone component based on at least two of the three fundamental wave components f _{1 to} f ₃ is extracted .

The invention according to claim 3 is the ultrasonic diagnostic apparatus according to claim 2.
The arithmetic unit is configured to use the second fundamental wave component and the first fundamental wave component as a difference tone component based on at least two of the first to third fundamental wave components f _{1 to} f ₃ . A difference tone component f ₂ −f ₁ , a difference tone component f ₃ −f _{2 of} the third fundamental wave component and the second fundamental wave component , and the third fundamental wave component and the first fundamental wave component And a difference tone component f ₃ −f ₁ of

The invention according to claim 4 is the ultrasonic diagnostic apparatus according to any one of claims 1 to 3 ,
The transmission unit outputs a first drive signal and a second drive signal as the drive signal,
The reception unit is configured to transmit first sound ray information based on a reception signal according to a reflection ultrasonic wave from a subject of transmission ultrasonic wave based on the first drive signal, and transmission ultrasonic wave based on the second drive signal. Generating second sound ray information based on the received signal according to the reflected ultrasound from the subject,
The calculation unit is characterized in that the first sound ray information and the second sound ray information are added by a pulse inversion method .

The invention according to claim 5 is the ultrasonic diagnostic apparatus according to claim 4 .
The second drive signal is a signal whose phase is inverted to that of the first drive signal .
The invention according to claim 6 is the ultrasonic diagnostic apparatus according to claim 4 or 5.
The calculation unit is characterized in that a harmonic wave is extracted by adding the first sound ray information from which the noise component has been removed and the second sound ray information from which the noise component has been removed.
The invention according to claim 7 is the ultrasonic diagnostic apparatus according to any one of claims 4 to 6,
The arithmetic unit subtracts the other from one of the first sound ray information and the second sound ray information to extract a harmonic.
The image processing unit is characterized in that the ultrasonic image data is generated based on the harmonics extracted by the addition and the harmonics extracted by the subtraction.
The invention according to claim 8 is the ultrasonic diagnostic apparatus according to claim 7.
The harmonic extracted by the subtraction includes the third harmonic component 3f ₁ of the _first fundamental wave component .

The invention according to claim 9, in the ultrasonic diagnostic apparatus according to any one of claims 1-8,
The transmission unit transmits or receives the intensity peak of the frequency power spectrum at 1/3 or less of the upper limit frequency of the ultrasonic probe in the transmission / reception frequency band and at -20 dB of the ultrasonic probe. A pulse signal included in a frequency band equal to or higher than the lower limit frequency of the frequency band is output.

The invention of claim 10 provides the ultrasonic diagnostic apparatus according to any one of claim 1 to 9
The transmitting unit is a pulse whose intensity peak of the frequency power spectrum is included in the lower frequency side than the central frequency of the -20 dB transmission frequency band of the ultrasonic probe and in the higher frequency side than the central frequency. It is characterized by outputting a signal.

The invention of claim 11 provides the ultrasonic diagnostic apparatus according to any one of claims 1-10,
The drive signal may be output by a control signal having five or less values.

The invention according to claim 12, in the ultrasonic diagnostic apparatus according to any one of claim 1 to 11
The ultrasonic probe is characterized in that a relative band of -20 dB is 100% or more.

The invention according to claim 13 is the ultrasonic diagnostic apparatus according to any one of claims 1 to 12 ,
The ultrasonic probe is characterized in that a relative band of -6 dB is 100% or more.

Claims (14)

An ultrasonic probe for outputting a transmission ultrasonic wave toward a subject based on the input pulse signal and outputting a reception signal by receiving a reflected ultrasonic wave from the subject;
A transmitter configured to output pulse signals of different drive waveforms to the ultrasonic probe a plurality of times at time intervals;
A receiving unit that generates a plurality of sound ray information based on each reception signal obtained from the reflected ultrasonic wave of the transmission ultrasonic wave generated by each of the plurality of pulse signals;
An operation unit that performs operations according to a plurality of types of operation methods using the plurality of pieces of sound ray information generated by the receiving unit, and obtains respective operation results;
A combining unit configured to combine a plurality of the calculation results obtained by the calculation unit;
A detection unit that detects the calculation result synthesized by the synthesis unit;
An image processing unit that generates ultrasound image data based on a result detected by the detection unit;
An ultrasonic diagnostic imaging apparatus comprising:   The ultrasound image diagnostic apparatus according to claim 1, wherein the calculation unit obtains an operation result obtained by adding the plurality of pieces of sound ray information and a calculation result obtained by subtracting the plurality of pieces of sound ray information.   A filter processing unit is provided that performs filter processing to cut the frequency band of the fundamental wave component included in the calculation result from the calculation result obtained by subtracting the plurality of sound ray information obtained by the calculation unit. The ultrasonic diagnostic imaging apparatus according to claim 2. The transmission unit includes a pulse signal for power modulation having a different amplitude from that of one of a plurality of pulse signals to be output in the pulse signal which is output a plurality of times, and outputs the pulse signal to the ultrasonic probe
The arithmetic unit performs predetermined multiplication of sound ray information generated by performing phasing addition on the reception signal obtained from the reflection ultrasonic wave of the transmission ultrasonic wave generated by the power modulation pulse signal by the reception unit. Performing power modulation processing to be amplified and added to the calculation result obtained by subtracting the plurality of sound ray information;
3. The apparatus according to claim 2, wherein the combining unit combines an operation result obtained by subtracting the plurality of pieces of sound ray information after the power modulation process and a calculation result obtained by adding the plurality of pieces of sound ray information. Ultrasound imaging system.   The phase of the second frequency component included in the other calculation result is matched with the phase of the first frequency component included in the calculation result of one of the plurality of calculation results obtained by the calculation unit. The ultrasound diagnostic imaging apparatus according to any one of claims 1 to 4, further comprising: a phase adjustment unit configured to adjust the phase of the calculation result of.   The ultrasound imaging apparatus according to claim 5, wherein the phase adjustment unit changes the adjustment amount of the phase of the other calculation result according to the depth.   The transmitter includes a pulse signal whose phase is inverted from that of one of a plurality of pulse signals to be output in the pulse signal which is output a plurality of times, and outputs the pulse signal to the ultrasonic probe. The ultrasound diagnostic imaging apparatus according to any one of claims 1 to 6, wherein   The transmission unit transmits or receives the intensity peak of the frequency power spectrum at 1/3 or less of the upper limit frequency of the ultrasonic probe in the transmission / reception frequency band and at -20 dB of the ultrasonic probe. The ultrasonic image diagnostic apparatus according to any one of claims 1 to 7, wherein a pulse signal included in a frequency band equal to or higher than the lower limit frequency of the frequency band is output.   The transmitting unit is a pulse whose intensity peak of the frequency power spectrum is included in the lower frequency side than the central frequency of the -20 dB transmission frequency band of the ultrasonic probe and in the higher frequency side than the central frequency. The ultrasound diagnostic imaging apparatus according to any one of claims 1 to 8, which outputs a signal.   The said transmission part is characterized by outputting the pulse signal in which the intensity | strength peak of a frequency power spectrum contains 2 or more by the high frequency side rather than the central frequency of the -20 dB transmission frequency zone | band of the said ultrasound probe. The ultrasound imaging apparatus according to 9.   The transmission unit has at least one local minimum in the transmission / reception frequency band of the ultrasonic probe in the frequency power spectrum intensity, and the local minimum and the ultrasonic probe The ultrasonic image diagnostic apparatus according to claim 9, characterized in that a pulse signal of a drive waveform whose difference from the maximum intensity in the transmission / reception frequency band of 6 dB is within 10 dB is output by a ternary control signal. .   The ultrasound image diagnostic apparatus according to any one of claims 1 to 11, wherein the pulse signal is output by a control signal having five or less values.   The ultrasound diagnostic imaging apparatus according to any one of claims 1 to 12, wherein the ultrasound probe has a relative bandwidth of -20 dB of 100% or more.   The ultrasound diagnostic imaging apparatus according to claim 13, wherein the ultrasound probe has a relative bandwidth of -6 dB of 100% or more.

Images