WO2011048939A1 - Ultrasound diagnosis apparatus - Google Patents

Ultrasound diagnosis apparatus Download PDF

Info

Publication number
WO2011048939A1
WO2011048939A1 PCT/JP2010/067413 JP2010067413W WO2011048939A1 WO 2011048939 A1 WO2011048939 A1 WO 2011048939A1 JP 2010067413 W JP2010067413 W JP 2010067413W WO 2011048939 A1 WO2011048939 A1 WO 2011048939A1
Authority
WO
WIPO (PCT)
Prior art keywords
signal
transmission
ultrasonic
reception
frequency
Prior art date
Application number
PCT/JP2010/067413
Other languages
French (fr)
Japanese (ja)
Inventor
大介 梶
義浩 武田
Original Assignee
コニカミノルタエムジー株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by コニカミノルタエムジー株式会社 filed Critical コニカミノルタエムジー株式会社
Priority to JP2011537196A priority Critical patent/JP5692083B2/en
Publication of WO2011048939A1 publication Critical patent/WO2011048939A1/en

Links

Images

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S15/00—Systems using the reflection or reradiation of acoustic waves, e.g. sonar systems
    • G01S15/88—Sonar systems specially adapted for specific applications
    • G01S15/89—Sonar systems specially adapted for specific applications for mapping or imaging
    • G01S15/8906—Short-range imaging systems; Acoustic microscope systems using pulse-echo techniques
    • G01S15/8959—Short-range imaging systems; Acoustic microscope systems using pulse-echo techniques using coded signals for correlation purposes
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S15/00—Systems using the reflection or reradiation of acoustic waves, e.g. sonar systems
    • G01S15/88—Sonar systems specially adapted for specific applications
    • G01S15/89—Sonar systems specially adapted for specific applications for mapping or imaging
    • G01S15/8906—Short-range imaging systems; Acoustic microscope systems using pulse-echo techniques
    • G01S15/8959—Short-range imaging systems; Acoustic microscope systems using pulse-echo techniques using coded signals for correlation purposes
    • G01S15/8963—Short-range imaging systems; Acoustic microscope systems using pulse-echo techniques using coded signals for correlation purposes using pulse inversion
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S15/00—Systems using the reflection or reradiation of acoustic waves, e.g. sonar systems
    • G01S15/88—Sonar systems specially adapted for specific applications
    • G01S15/89—Sonar systems specially adapted for specific applications for mapping or imaging
    • G01S15/8906—Short-range imaging systems; Acoustic microscope systems using pulse-echo techniques
    • G01S15/895—Short-range imaging systems; Acoustic microscope systems using pulse-echo techniques characterised by the transmitted frequency spectrum
    • G01S15/8954—Short-range imaging systems; Acoustic microscope systems using pulse-echo techniques characterised by the transmitted frequency spectrum using a broad-band spectrum
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/52—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S15/00
    • G01S7/52017—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S15/00 particularly adapted to short-range imaging
    • G01S7/52023—Details of receivers
    • G01S7/52036—Details of receivers using analysis of echo signal for target characterisation
    • G01S7/52038—Details of receivers using analysis of echo signal for target characterisation involving non-linear properties of the propagation medium or of the reflective target

Definitions

  • the present invention relates to an ultrasonic diagnostic apparatus.
  • Ultrasound diagnostic devices can display images of a subject on a monitor in almost real time for observation, and do not give radiation exposure to a subject unlike radiation-sensitive image diagnostic devices. It is used in the field.
  • the ultrasonic waveform transmitted from the ultrasonic probe of the ultrasonic imaging apparatus to the living body determines the distance resolution because the length of the waveform determines the distance resolution, so it is better to use a pulse wave that is as short as possible in the time axis direction.
  • Patent Document 1 a coded signal extended in the time axis direction is transmitted, a signal reflected in the subject is received, converted into an electric signal, decoded, and compressed in the time axis direction, A description is given of distributed compression transmission / reception by an encoded transmission / reception method for returning to a pulse waveform having a large peak value.
  • Patent Document 2 a linear chirp signal is transmitted, a signal reflected in a subject is received, converted into an electrical signal, and then demodulated by obtaining a cross-correlation between the received signal waveform and the transmitted signal.
  • the spread compression transmission / reception by the spread spectrum method is described.
  • HI harmonic imaging
  • Patent Document 4 As a technique for extracting higher-order harmonics, a method using pulse inversion is known. For example, in Patent Document 4, a set of ultrasonic waves whose phases are inverted with respect to each other is transmitted, and a difference between a received signal corresponding to one of the ultrasonic sets and a received signal corresponding to the other is calculated. A method for extracting third-order harmonic components is disclosed.
  • JP 2003-225237 A Japanese Patent Laid-Open No. 7-79973 Japanese Patent No. 4116143 JP 2009-136626 A
  • the frequency bands of the transmission signal overlap each other because the frequency bands of the fundamental wave and the harmonics overlap each other, so that only the target n-order harmonics are applied even if pulse inversion is applied. It was difficult to extract.
  • This invention is made in view of the said subject, Comprising: It aims at providing the ultrasonic diagnostic apparatus which can extract the target nth-order harmonic using transmission / reception by dispersion
  • the present invention has the following characteristics.
  • An ultrasonic probe that transmits ultrasonic waves to the subject, a first transmission signal that is distributed and compressed having a component of a desired fundamental frequency, and a second transmission signal that is an inversion of the first transmission signal, in this order.
  • a transmission processing unit that generates and drives the ultrasound probe; a first reception signal that corresponds to the first transmission signal that is received by the ultrasound probe; and a second signal that corresponds to the second transmission signal.
  • a reception processing unit that expands and outputs at least one of a difference signal or a sum signal from the received signal of 2; an image generation unit that generates an ultrasonic image using the expanded signal output from the reception processing unit; A display unit for displaying an ultrasonic image generated by the image generation unit, and an ultrasonic diagnostic apparatus comprising: When the fundamental frequency of the ultrasonic wave transmitted from the ultrasonic probe is f 0 , and the upper limit frequency of the frequency band is f 2 , f 2 ⁇ 2f 0 is satisfied. Ultrasonic diagnostic equipment.
  • the gain of the sound pressure of the ultrasonic wave transmitted from the ultrasonic probe is Increases as the frequency than the fundamental frequency f 0 is higher, the ultrasonic diagnostic apparatus according to 1 or 2, characterized in that it has a decreasing frequency range as the frequency than the fundamental frequency f 0 is lowered.
  • the reception processing unit A delay unit that delays the first reception signal for a time difference between a time at which transmission of the first reception signal is started and a time at which transmission of the second reception signal is started; A subtractor that calculates a difference between the output of the delay unit and the second received signal as the difference signal;
  • the ultrasonic diagnostic apparatus according to any one of 1 to 3, characterized by comprising:
  • the reception processing unit A delay unit that delays the first reception signal for a time difference between a time at which transmission of the first reception signal is started and a time at which transmission of the second reception signal is started; An adder that calculates the sum of the output of the delay unit and the second received signal as the sum signal;
  • the ultrasonic diagnostic apparatus according to any one of 1 to 4, characterized by comprising:
  • the reception processing unit A demodulation filter for expanding distributed compression by a modulation code string for the differential signal or the sum signal; An envelope detector for detecting and outputting an envelope of the signal expanded by the demodulation filter;
  • the ultrasonic diagnostic apparatus according to 4 or 5 above, characterized by comprising:
  • the transmission processing unit 7 The ultrasonic diagnostic apparatus according to any one of 4 to 6, wherein a set of Barker codes whose signs are inverted with respect to each other are generated as the first transmission signal and the second transmission signal. .
  • the transmission processing unit 8 The ultrasonic diagnostic apparatus according to 7, wherein the first transmission signal and the second transmission signal are subjected to PSK modulation and output.
  • the transmission processing unit 7 The ultrasonic diagnostic apparatus according to any one of 4 to 6, wherein a set of chirp signals whose phases are inverted with respect to each other are generated as the first transmission signal and the second transmission signal. .
  • the basic frequency of the ultrasonic wave transmitted from the ultrasonic probe is f 0 and the upper limit frequency of the frequency band is f 2 .
  • f 2 ⁇ 2f 0 is satisfied.
  • the fundamental wave band of the received signal and the third harmonic band do not overlap, it is possible to extract a harmonic of a predetermined order by applying pulse inversion.
  • the target n-order harmonic can be extracted using transmission / reception by distributed compression.
  • FIG. 1 is a block diagram showing an electrical configuration of an ultrasonic diagnostic apparatus according to an embodiment. It is a circuit block diagram of an example of the transmission processing unit 1 of the embodiment. It is a figure explaining the Barker code
  • FIG. It is a detailed circuit block diagram of the other example of the transmission process part 1 of embodiment. It is a figure explaining the chirp signal produced
  • 4 is a graph showing an example of frequency characteristics of ultrasonic waves transmitted from the ultrasonic probe 2; It is a figure explaining the frequency spectrum of the received signal after addition or subtraction.
  • 6 is a graph showing an example of frequency characteristics in which the frequency characteristics of ultrasonic waves transmitted from the ultrasonic probe 2 are set to (f 0 ⁇ f 1 )> (f 2 ⁇ f 0 ). It is a graph which shows the example of a frequency characteristic in which the gain of the ultrasonic wave transmitted from the ultrasonic probe 2 increases in proportion to the frequency.
  • FIG. 1 is a block diagram showing an electrical configuration of the ultrasonic diagnostic apparatus according to the embodiment
  • FIG. 2 is a circuit block diagram of an example of the transmission processing unit 1 of the embodiment
  • FIG. It is a figure explaining the Barker code
  • the ultrasonic image observation apparatus 100 transmits an ultrasonic wave (ultrasonic signal) from the ultrasonic probe 2 to a not-illustrated subject, for example, the abdomen of a pregnant woman, and reflects the ultrasonic wave reflected from the inside of the subject.
  • the state of the fetus in the subject is imaged as an ultrasound image from the reflected wave (echo, ultrasound signal) and displayed on the display unit 10.
  • the input unit 13 includes a power switch for turning on the ultrasonic image observation apparatus 100 and input means such as a keyboard and a touch panel.
  • the control unit 99 includes a CPU 98 (central processing unit), a storage unit 96, and the like, reads a program stored in the storage unit 96 into a RAM (Random Access Memory), and each unit of the ultrasonic image observation apparatus 100 according to the program.
  • the storage unit 96 includes a RAM (Random Access Memory), a ROM (Read Only Memory), a hard disk, and the like.
  • the ultrasonic probe 2 transmits an ultrasonic wave to a subject (not shown) and receives a reflected wave of the ultrasonic wave reflected by the subject. As shown in FIG. 1, the ultrasound probe 2 is electrically connected to a transmission processing unit 1 and a reception processing unit 3.
  • the ultrasonic probe 2 transmits ultrasonic waves by the transmission signal transmitted from the transmission processing unit 1.
  • the transmission processing unit 1 includes a timing signal generation unit 25, a code selection unit 26, a code storage unit 23, a PSK modulation unit 22, an FLT 29, and a transmission amplifier 21.
  • the timing signal generation unit 25 supplies a timing clock to each unit of the transmission processing unit 1 according to a command from the control unit 99.
  • the code selection unit 26 selects any one of a plurality of types of modulation codes having the encoding order stored in the code storage unit 23 according to a command from the control unit 99.
  • An operator such as a doctor can set the type of modulation code selected by the code selection unit 26 by operating from the input unit 13.
  • the code storage unit 23 stores in advance at least one set of modulation codes whose codes are in an inverted relationship.
  • the modulation code is a known Barker code, and a modulation code that is a combination of Barker codes of a predetermined encoding order is stored in the code storage unit 23 in advance.
  • FIG. 3 is an example of a set of Barker codes stored in the code storage unit 23 and whose codes are in an inverted relationship with each other.
  • FIG. 3 shows an example of a Barker code with a 5th-order encoding.
  • the (+1, +1, +1, ⁇ 1, +1) portion is the first transmission signal, followed by ( ⁇ 1, ⁇ 1, ⁇ 1, +1, ⁇ 1) are second transmission signals obtained by inverting the first transmission signal. As described above, the first transmission signal and the second transmission signal are sequentially output from the code storage unit 23.
  • the code selection unit 26 controls the output of the code storage unit 23 storing the modulation code at a predetermined time interval T by designating the address.
  • a PSK (Phase Shift Keying) modulation unit 22 modulates the phase of a carrier wave having a constant frequency according to the code element coefficient +1 or ⁇ 1 output from the code storage unit 23. That is, a basic waveform (phase 0 °) and a waveform that is 180 ° out of phase with respect to the basic waveform are output.
  • PSK modulation a large amount of information can be transmitted in a narrow frequency band and can be made less susceptible to noise and signal attenuation.
  • FLT 29 is a filter such as a band pass filter that limits the band of the transmission signal. The characteristics of the FLT 29 will be described in detail later.
  • the echoes returned to the ultrasonic probe 2 are mechanically operated by piezoelectric elements (not shown) arranged in the ultrasonic probe 2.
  • the reception signal corresponding to the ultrasonic wave transmitted by the first transmission signal is the first reception signal
  • the reception signal corresponding to the ultrasonic wave transmitted by the second transmission signal is the second reception signal.
  • the reception processing unit 3 receives the first reception signal and the second reception signal in order and amplifies them to a predetermined signal level, and then performs pulse inversion on the first reception signal and the second reception signal to perform basic processing. After the components of the wave or harmonics that have been distributed and compressed are extracted and expanded, a signal subjected to envelope detection is output. The signal processing performed by the reception processing unit 3 will be described in detail later.
  • the image generation unit 6 generates a B-mode image based on the signal output from the reception processing unit 3.
  • the image processed by the image processing unit is converted into a video signal by a digital scan converter (DSC) 9 and displayed on the display unit 10.
  • DSC digital scan converter
  • the Barker code with the encoding order of 5 is described as an example of the modulation code output from the transmission processing unit 1, but the order is not particularly limited to this order. What is necessary is just to set the order from which an optimal image is obtained according to the contrast of a detection target.
  • FIG. 4 is a detailed circuit block diagram of another example of the transmission processing unit 1 according to the embodiment
  • FIG. 5 is a diagram illustrating a chirp signal generated in the present embodiment.
  • the code generator 27 stores a code for generating a chirp signal in advance, and outputs the stored code in accordance with a predetermined clock according to a command from the controller 99.
  • the D / A converter 26 converts the code sequentially output from the code generation unit 27 into an analog signal and outputs the analog signal.
  • FIG. 5 is a diagram for explaining the generated chirp signal.
  • a period T1 is a first transmission signal
  • a period T2 is a second transmission signal obtained by inverting the first transmission signal.
  • the first transmission signal and the second transmission signal are chirp signals whose frequency increases with time.
  • FLT 29 is a filter such as a band pass filter that limits the band of the transmission signal. The characteristics of the FLT 29 will be described in detail later.
  • FIG. 6 is a block diagram showing the electrical configuration of the reception processing unit of the first embodiment
  • FIG. 7 is a block diagram showing the electrical configuration of the reception processing unit of the second embodiment.
  • the reception circuit 31 sequentially receives the first reception signal and the second reception signal output from the ultrasound probe 2 and amplifies them to a predetermined signal level.
  • the amplified signal is converted into a digital value by the A / D converter 32.
  • the delay unit 33 is, for example, a line memory, and delays the first reception signal for a time corresponding to the time difference between the time when transmission of the first reception signal is started and the time when transmission of the second reception signal is started.
  • the output of the A / D converter 32 is input to the delay unit 33, and the first received signal is delayed for a time corresponding to the time difference and input to the subtractor 34.
  • the subtracter 34 subtracts the input signal of the delay unit 33 and the output signal of the delay unit 33. Since the first reception signal is delayed by the delay unit 33 as described above, the first reception signal and the second reception signal are simultaneously input to the subtractor 34, and the first reception signal and the second reception signal are input. The difference between the received signals is output from the subtracter 34 as a difference signal.
  • the difference signal is removed by subtracting the component of the second harmonic 2f 0 having the same phase between the first received signal and the second received signal, and the first received signal and the second received signal are reversed. remaining ingredients and components of the third harmonic 3f 0 of the fundamental frequency f 0 of the phase.
  • Differential signal is inputted to the fundamental wave LPF (low pass filter) 36 and the third harmonic BPF (band pass filter) 35 is separated into components of the component of the fundamental frequency f 0 and the third-order harmonic 3f 0.
  • the fundamental wave LPF 36 mainly passes the fundamental frequency f 0 of the ultrasonic wave transmitted by the ultrasonic probe 2 included in the output of the subtractor 34 and the sideband band thereof.
  • the third harmonic BPF 35 mainly passes the band of the third harmonic 3f 0 of the ultrasonic wave transmitted by the ultrasonic probe 2 included in the output of the subtractor 34 and its sideband.
  • the SW (switch) 37 switches the output of the fundamental wave LPF 36 or the third harmonic BPF 35 in accordance with a command from the control unit 99 and outputs it to the mismatch filter (demodulation filter) 39.
  • the mismatch filter 39 is configured by an FIR filter or the like, holds a coefficient corresponding to the modulation signal generated by the transmission processing unit 1 in advance, and expands the received dispersion-compressed signal.
  • the mismatch filter coefficient obtained by inverting the coefficient of the Barker code with respect to the time axis is supplied to the mismatch filter 39 from the control unit 99 during ultrasonic transmission. Is set.
  • the mismatch filter coefficient is a coefficient whose coefficient magnitude is determined not to be 1 so as to minimize the side lobe while keeping the peak value as much as possible.
  • the mismatch filter 39 performs a product-sum operation on the received signal value and the mismatch filter coefficient, and expands the result.
  • the envelope detection unit 40 detects the output of the mismatch filter 39 and outputs the detection output to the image generation unit 6.
  • the first reception signal is delayed by the delay unit 33, the first reception signal and the second reception signal are simultaneously input to the delay unit 33, and the first reception signal and the second reception signal are input. A sum signal obtained by adding the received signals is output.
  • the sum signal is removed by the components of the first received signal and the component and the third harmonic 3f 0 of the fundamental frequency f 0 of the opposite phase with the second reception signal is added, the first received signal and the The second harmonic 2f 0 component remains in phase with the received signal 2.
  • the sum signal is input to the second harmonic wave BPF (band pass filter) 42, the component of the second harmonic 2f 0 is separated.
  • SW 37 switches the output of the fundamental wave LPF 36, the second harmonic BPF 42, or the third harmonic BPF 35 according to a command from the control unit 99, and outputs it to the mismatch filter 39.
  • any one of the fundamental wave LPF 36, the second harmonic BPF 42, or the third harmonic BPF 35 is provided, and the switching by the SW 37 is not performed, and the second harmonic BPF 42 and the third harmonic are not switched.
  • a configuration in which two of the waves BPF 35 are switched may be used.
  • a pair of ultrasonic waves whose phases are inverted with respect to each other is transmitted, and a difference signal or a sum of a reception signal corresponding to one of the ultrasonic waves and a reception signal corresponding to the other is transmitted.
  • the signal can be calculated to extract the nth-order harmonic component.
  • FIG. 8 is a graph showing an example of the frequency characteristic of the ultrasonic wave transmitted from the ultrasonic probe 2
  • FIG. 9 is a diagram for explaining the frequency spectrum of the received signal after addition or subtraction.
  • f 0 is the fundamental frequency of the ultrasonic wave transmitting from the ultrasound probe 2
  • G 0 is the gain of the ultrasonic sound pressure at the fundamental frequency f 0.
  • f 1 and f 2 are the frequencies at which the 3 dB gain decreases from the gain G 0 . Therefore, f 1 is the lower limit frequency of the frequency band, and f 2 is the upper limit frequency of the frequency band.
  • f 2 ⁇ 2f 0 and the frequency component higher than 2f 0 which is twice the frequency of f 0 which is the frequency of the second harmonic is sufficiently attenuated.
  • f 1 when f 0 is 3 MHz, f 1 may be 1 MHz and f 2 may be 5 MHz. Since 2f 0 is 6 MHz and satisfies the condition of f 2 ⁇ 2f 0 , it is possible to extract 6 MHz and the third harmonic, which are second harmonics.
  • Such a frequency characteristic of the ultrasonic wave transmitted from the ultrasonic probe 2 can be realized, for example, by limiting the band by using the FLT 29 of the transmission processing unit as a bandpass filter having a frequency characteristic as shown in FIG.
  • the frequency band of the piezoelectric element of the ultrasonic probe 2 or the transmission amplifier 21 is sufficiently wide, the frequency band is mainly determined by the FLT 29. If these frequency bands are narrow, the frequency of the piezoelectric element is determined. It is desirable to set in consideration of the overall characteristics such as the characteristics and the characteristics of the transmission amplifier 21.
  • FIG. 9A shows an output example obtained by subtracting the reception signal when the ultrasonic wave having the frequency characteristic shown in FIG. 8 is transmitted by the subtractor 34
  • FIG. 9B is an output example of the adder 41.
  • the fundamental frequency component 51 and the third harmonic component 53 remaining in the difference signal after subtraction are indicated by a solid line
  • the removed second harmonic component 52 is indicated by a dotted line. Yes.
  • the second harmonic component 52 remaining in the sum signal after addition is indicated by a solid line
  • the removed fundamental frequency component 51 and third harmonic component 53 are indicated by a dotted line. Yes.
  • the frequency of two times f 0 component 51 of the fundamental frequency of the received signal around the f 0 as shown in FIG. 9 (a) 2f is distributed in a frequency range lower than 0 .
  • the third-harmonic component 53 of the received signal is distributed in a frequency range higher than 2f 0 around a frequency 3f 0 that is three times f 0 .
  • the second harmonic component 52 after subtraction as shown in FIG. 9A using pulse inversion.
  • the fundamental frequency component 51 and the third harmonic component 53 can be left. Thereafter, the fundamental frequency component 51 and the third harmonic component 53 can be easily separated by passing the fundamental LPF 36 and the third harmonic BPF 35.
  • the fundamental frequency component 51 and the third harmonic component 53 do not overlap in frequency band, using the pulse inversion, the fundamental frequency component 51 and the third order component are added as shown in FIG. 9B.
  • the harmonic component 53 can be removed, and the second harmonic component 52 can be left. Thereafter, the second harmonic component 52 can be easily separated by passing the second harmonic BPF 42.
  • the signal level after expansion can be increased.
  • the frequency characteristics of the ultrasonic wave to be transmitted may be set to (f 0 ⁇ f 1 )> (f 2 ⁇ f 0 )
  • FIG. 10 is a graph showing another example of frequency characteristics of ultrasonic waves transmitted from the ultrasonic probe 2.
  • f 1 when f 0 is 3 MHz, f 1 may be 0.5 MHz and f 2 may be 4 MHz.
  • f 0 -f 1 is 2.5 MHz, and f 2 -f 0 is 1 MHz, which satisfies the condition (f 0 -f 1 )> (f 2 -f 0 ).
  • the ultrasonic frequency characteristic transmitting from the ultrasound probe 2 as shown in FIG. 11 increased gain than the gain G 0 of the fundamental frequency f 0 as the frequency becomes higher than the fundamental frequency f 0, the basic A frequency range in which the gain decreases from the gain G 0 as the frequency becomes lower than the frequency f 0 may be provided.
  • the gain increases in proportion to the frequency between f 1 and f B including f 0 .
  • f 0 3 MHz
  • f 1 1 MHz
  • f 2 5 MHz
  • f B 4.5 MHz

Abstract

N-th order harmonics subjected to extraction are extracted by use of transmission and reception which are performed with distributed compression. Provided is an ultrasound diagnosis apparatus characterized by being configured so that, when f0 and f2 denote the fundamental frequency of ultrasound transmitted from an ultrasound probe and a frequency at the upper limit of the frequency band thereof, f2 0 can be satisfied.

Description

超音波診断装置Ultrasonic diagnostic equipment
　本発明は、超音波診断装置に関する。 The present invention relates to an ultrasonic diagnostic apparatus.
　超音波診断装置は、被検体の画像をほぼリアルタイムでモニタに表示して観察でき、また、放射線を用いる画像診断装置のような放射線被爆を被検体に与えないことから安全性も高く、広く医療の分野で用いられている。 Ultrasound diagnostic devices can display images of a subject on a monitor in almost real time for observation, and do not give radiation exposure to a subject unlike radiation-sensitive image diagnostic devices. It is used in the field.
　超音波撮像装置の超音波探触子から生体に対して送波する超音波の波形は、その波形の長さが距離分解能を決めるので、できるだけ時間軸方向に短いパルス波を用いる方が良い。 The ultrasonic waveform transmitted from the ultrasonic probe of the ultrasonic imaging apparatus to the living body determines the distance resolution because the length of the waveform determines the distance resolution, so it is better to use a pulse wave that is as short as possible in the time axis direction.
　一方で、ノイズに対する信号の強度比であるＳ／Ｎ比を良くするには信号強度が大きい方が良いが、生体に与える影響を考慮して信号強度を一定値以下に制限する必要がある。そのため、パルスの発生する時間や周波数を分散させた分散圧縮送受信が用いられている。 On the other hand, in order to improve the S / N ratio, which is the signal intensity ratio with respect to noise, it is better that the signal intensity is high, but it is necessary to limit the signal intensity to a certain value or less in consideration of the influence on the living body. Therefore, distributed compression transmission / reception in which the time and frequency at which pulses are generated is distributed is used.
　例えば、特許文献１には、時間軸方向に伸ばした符号化信号を送波し、被検体内で反射した信号を受波し、電気信号に変換した後に復号して時間軸方向に圧縮し、ピーク値の大きいパルス波形に戻す符号化送受信法による分散圧縮送受信が記載されている。 For example, in Patent Document 1, a coded signal extended in the time axis direction is transmitted, a signal reflected in the subject is received, converted into an electric signal, decoded, and compressed in the time axis direction, A description is given of distributed compression transmission / reception by an encoded transmission / reception method for returning to a pulse waveform having a large peak value.
　特許文献２には、リニアチャープ信号を送波し、被検体内で反射した信号を受波し、電気信号に変換した後に、受信した信号波形と送波信号との相互相関を求めることにより復調するスペクトラム拡散方式による分散圧縮送受信が記載されている。 In Patent Document 2, a linear chirp signal is transmitted, a signal reflected in a subject is received, converted into an electrical signal, and then demodulated by obtaining a cross-correlation between the received signal waveform and the transmitted signal. The spread compression transmission / reception by the spread spectrum method is described.
　また、従来より超音波診断装置では、超音波の非線形な伝播により生じる高調波成分を取りだし、この高調波成分に基づいて超音波画像を生成し、表示するハーモニックイメージング（ＨＩ）法と呼ばれている手法が用いられてきた（例えば、特許文献３参照）。高調波成分を利用すると、Ｓ／Ｎの向上や横方向分解能の向上、多重反射の抑制等の様々な利点がある。 Conventionally, in an ultrasonic diagnostic apparatus, it is called a harmonic imaging (HI) method in which a harmonic component generated by nonlinear propagation of an ultrasonic wave is taken out and an ultrasonic image is generated and displayed based on the harmonic component. Have been used (see, for example, Patent Document 3). The use of the harmonic component has various advantages such as improvement of S / N, improvement of lateral resolution, and suppression of multiple reflection.
　高次の高調波を抽出する技術としては、パルスインバージョンによる方法が知られている。例えば、特許文献４では、互いに位相が反転関係にある超音波の組を送波し、この超音波の組のうち一方に対応する受信信号と、他方に対応する受信信号の差分を算出して３次の高調波成分を抽出する方法が開示されている。 As a technique for extracting higher-order harmonics, a method using pulse inversion is known. For example, in Patent Document 4, a set of ultrasonic waves whose phases are inverted with respect to each other is transmitted, and a difference between a received signal corresponding to one of the ultrasonic sets and a received signal corresponding to the other is calculated. A method for extracting third-order harmonic components is disclosed.
特開２００３－２２５２３７号公報JP 2003-225237 A 特開平７－７９９７３号公報Japanese Patent Laid-Open No. 7-79973 特許第４１１６１４３号公報Japanese Patent No. 4116143 特開２００９－１３６６２６号公報JP 2009-136626 A
　分散圧縮送受信を用いる場合も、高調波成分を抽出することができればより一層の画質の向上が期待できる。 Even when using distributed compression transmission / reception, further improvement in image quality can be expected if harmonic components can be extracted.
　しかしながら、分散圧縮送受信を用いる場合は送信信号の周波数帯域の広さから基本波と高調波との互いの周波数帯域が重なるため、パルスインバージョンを適用しても対象とするｎ次高調波のみを抽出することが困難であった。 However, when using distributed compression transmission / reception, the frequency bands of the transmission signal overlap each other because the frequency bands of the fundamental wave and the harmonics overlap each other, so that only the target n-order harmonics are applied even if pulse inversion is applied. It was difficult to extract.
　本発明は、上記課題に鑑みてなされたものであって、分散圧縮による送受信を用いて対象とするｎ次高調波を抽出することができる超音波診断装置を提供することを目的とする。 This invention is made in view of the said subject, Comprising: It aims at providing the ultrasonic diagnostic apparatus which can extract the target nth-order harmonic using transmission / reception by dispersion | distribution compression.
　上記の課題を解決するため、本発明は以下のような特徴を有するものである。 In order to solve the above problems, the present invention has the following characteristics.
　１．被検体に超音波を送波する超音波探触子と、所望の基本周波数の成分を有する分散圧縮した第１の送信信号と前記第１の送信信号を反転した第２の送信信号とを順に生成して超音波探触子を駆動する送信処理部と、前記超音波探触子が受信した前記第１の送信信号に対応する第１の受信信号と前記第２の送信信号に対応する第２の受信信号との差分信号または和信号の少なくとも一方を伸張して出力する受信処理部と、前記受信処理部の出力する伸張された信号を用いて超音波画像を生成する画像生成部と、前記画像生成部で生成された超音波画像を表示する表示部と、を備えた超音波診断装置であって、
　前記超音波探触子から送波される超音波の基本周波数をｆ０、周波数帯域の上限の周波数をｆ２とすると、ｆ２＜２ｆ０になるように構成されていることを特徴とする超音波診断装置。 1. An ultrasonic probe that transmits ultrasonic waves to the subject, a first transmission signal that is distributed and compressed having a component of a desired fundamental frequency, and a second transmission signal that is an inversion of the first transmission signal, in this order. A transmission processing unit that generates and drives the ultrasound probe; a first reception signal that corresponds to the first transmission signal that is received by the ultrasound probe; and a second signal that corresponds to the second transmission signal. A reception processing unit that expands and outputs at least one of a difference signal or a sum signal from the received signal of 2; an image generation unit that generates an ultrasonic image using the expanded signal output from the reception processing unit; A display unit for displaying an ultrasonic image generated by the image generation unit, and an ultrasonic diagnostic apparatus comprising:
When the fundamental frequency of the ultrasonic wave transmitted from the ultrasonic probe is f 0 , and the upper limit frequency of the frequency band is f 2 , f 2 <2f 0 is satisfied. Ultrasonic diagnostic equipment.
　２．周波数帯域の下限の周波数をｆ１とすると（ｆ０－ｆ１）＞（ｆ２－ｆ０）であることを特徴とする前記１に記載の超音波診断装置。 2. 2. The ultrasonic diagnostic apparatus according to 1 above, wherein (f 0 −f 1 )> (f 2 −f 0 ), where f 1 is a lower limit frequency of the frequency band.
　３．前記超音波探触子から送波される超音波の音圧の利得は、
　基本周波数ｆ０より周波数が高くなるにつれて増加し、基本周波数ｆ０より周波数が低くなるにつれて減少する周波数範囲を有することを特徴とする前記１または２に記載の超音波診断装置。 3. The gain of the sound pressure of the ultrasonic wave transmitted from the ultrasonic probe is
Increases as the frequency than the fundamental frequency f 0 is higher, the ultrasonic diagnostic apparatus according to 1 or 2, characterized in that it has a decreasing frequency range as the frequency than the fundamental frequency f 0 is lowered.
　４．前記受信処理部は、
　前記第１の受信信号の送信を開始した時間と前記第２の受信信号の送信を開始した時間の時間差に相当する間、前記第１の受信信号を遅延させる遅延部と、
　前記遅延部の出力と、前記第２の受信信号との差分を前記差分信号として算出する減算器と、
　を有することを特徴とする前記１から３の何れか１項に記載の超音波診断装置。 4). The reception processing unit
A delay unit that delays the first reception signal for a time difference between a time at which transmission of the first reception signal is started and a time at which transmission of the second reception signal is started;
A subtractor that calculates a difference between the output of the delay unit and the second received signal as the difference signal;
The ultrasonic diagnostic apparatus according to any one of 1 to 3, characterized by comprising:
　５．前記受信処理部は、
　前記第１の受信信号の送信を開始した時間と前記第２の受信信号の送信を開始した時間の時間差に相当する間、前記第１の受信信号を遅延させる遅延部と、
　前記遅延部の出力と、前記第２の受信信号との和を前記和信号として算出する加算器と、
　を有することを特徴とする前記１から４の何れか１項に記載の超音波診断装置。 5. The reception processing unit
A delay unit that delays the first reception signal for a time difference between a time at which transmission of the first reception signal is started and a time at which transmission of the second reception signal is started;
An adder that calculates the sum of the output of the delay unit and the second received signal as the sum signal;
The ultrasonic diagnostic apparatus according to any one of 1 to 4, characterized by comprising:
　６．前記受信処理部は、
　前記差分信号または前記和信号について変調符号列による分散圧縮を伸張する復調フィルタと、
　前記復調フィルタによって伸張された信号の包絡線を検波して出力する包絡線検波部と、
　を有することを特徴とする前記４または５に記載の超音波診断装置。 6). The reception processing unit
A demodulation filter for expanding distributed compression by a modulation code string for the differential signal or the sum signal;
An envelope detector for detecting and outputting an envelope of the signal expanded by the demodulation filter;
The ultrasonic diagnostic apparatus according to 4 or 5 above, characterized by comprising:
　７．前記送信処理部は、
　互いに符号が反転関係にある１組のＢａｒｋｅｒ符号を前記第１の送信信号および前記第２の送信信号として生成することを特徴とする前記４から６の何れか１項に記載の超音波診断装置。 7). The transmission processing unit
7. The ultrasonic diagnostic apparatus according to any one of 4 to 6, wherein a set of Barker codes whose signs are inverted with respect to each other are generated as the first transmission signal and the second transmission signal. .
　８．前記送信処理部は、
　前記第１の送信信号および前記第２の送信信号にＰＳＫ変調を行って出力することを特徴とする前記７に記載の超音波診断装置。 8). The transmission processing unit
8. The ultrasonic diagnostic apparatus according to 7, wherein the first transmission signal and the second transmission signal are subjected to PSK modulation and output.
　９．前記送信処理部は、
　互いに位相が反転関係にある１組のチャープ信号を前記第１の送信信号および前記第２の送信信号として生成することを特徴とする前記４から６の何れか１項に記載の超音波診断装置。 9. The transmission processing unit
7. The ultrasonic diagnostic apparatus according to any one of 4 to 6, wherein a set of chirp signals whose phases are inverted with respect to each other are generated as the first transmission signal and the second transmission signal. .
　本発明によれば、超音波探触子から送波される超音波の基本周波数をｆ０、周波数帯域の上限の周波数をｆ２とすると、ｆ２＜２ｆ０になるように構成されている。このようにすると、受信信号の基本波の帯域と３次高調波の帯域が重ならないのでパルスインバージョンを適用して所定の次数の高調波を抽出することができる。 According to the present invention, when the basic frequency of the ultrasonic wave transmitted from the ultrasonic probe is f 0 and the upper limit frequency of the frequency band is f 2 , f 2 <2f 0 is satisfied. . In this way, since the fundamental wave band of the received signal and the third harmonic band do not overlap, it is possible to extract a harmonic of a predetermined order by applying pulse inversion.
　したがって、分散圧縮による送受信を用いて対象とするｎ次高調波を抽出することができる。 Therefore, the target n-order harmonic can be extracted using transmission / reception by distributed compression.
実施形態に係る超音波診断装置の電気的な構成を示すブロック図である。1 is a block diagram showing an electrical configuration of an ultrasonic diagnostic apparatus according to an embodiment. 実施形態の送信処理部１の一例の回路ブロック図である。It is a circuit block diagram of an example of the transmission processing unit 1 of the embodiment. 符号化の次数が５のＢａｒｋｅｒ符号を説明する図である。It is a figure explaining the Barker code | symbol whose encoding order is 5. FIG. 実施形態の送信処理部１の他の例の詳細な回路ブロック図である。It is a detailed circuit block diagram of the other example of the transmission process part 1 of embodiment. 本実施形態で生成するチャープ信号を説明する図である。It is a figure explaining the chirp signal produced | generated in this embodiment. 第１の実施形態の受信処理部の電気的な構成を示すブロック図である。It is a block diagram which shows the electrical structure of the reception process part of 1st Embodiment. 第２の実施形態に係る超音波診断装置の電気的な構成を示すブロック図である。It is a block diagram which shows the electrical structure of the ultrasonic diagnosing device which concerns on 2nd Embodiment. 超音波探触子２から送波される超音波の周波数特性の一例を示すグラフである。4 is a graph showing an example of frequency characteristics of ultrasonic waves transmitted from the ultrasonic probe 2; 加算または減算後の受信信号の周波数スペクトラムを説明する図である。It is a figure explaining the frequency spectrum of the received signal after addition or subtraction. 超音波探触子２から送波される超音波の周波数特性を（ｆ０－ｆ１）＞（ｆ２－ｆ０）にした周波数特性例を示すグラフである。6 is a graph showing an example of frequency characteristics in which the frequency characteristics of ultrasonic waves transmitted from the ultrasonic probe 2 are set to (f 0 −f 1 )> (f 2 −f 0 ). 超音波探触子２から送波される超音波の利得が周波数に比例して増加する周波数特性例を示すグラフである。It is a graph which shows the example of a frequency characteristic in which the gain of the ultrasonic wave transmitted from the ultrasonic probe 2 increases in proportion to the frequency.
　以下、本発明に係る実施の一形態を図面に基づいて説明するが、本発明は該実施の形態に限られない。なお、各図において同一の符号を付した構成は、同一の構成であることを示し、その説明を省略する。 Hereinafter, an embodiment according to the present invention will be described with reference to the drawings. However, the present invention is not limited to the embodiment. In addition, the structure which attached | subjected the same code | symbol in each figure shows that it is the same structure, The description is abbreviate | omitted.
　図１は、実施形態に係る超音波診断装置の電気的な構成を示すブロック図、図２は、実施形態の送信処理部１の一例の回路ブロック図、図３は、符号化の次数が５のＢａｒｋｅｒ符号を説明する図である。 FIG. 1 is a block diagram showing an electrical configuration of the ultrasonic diagnostic apparatus according to the embodiment, FIG. 2 is a circuit block diagram of an example of the transmission processing unit 1 of the embodiment, and FIG. It is a figure explaining the Barker code | symbol of.
　最初に図１、図２、図３を用いて超音波診断装置の構成の一例を説明する。 First, an example of the configuration of the ultrasonic diagnostic apparatus will be described with reference to FIG. 1, FIG. 2, and FIG.
　超音波画像観察装置１００は、超音波探触子２から図略の被検体である例えば妊婦の腹部に対して超音波（超音波信号）を送信し、被検体の内部から反射した超音波の反射波（エコー、超音波信号）から被検体内の胎児の状態を超音波画像として画像化し、表示部１０に表示する。 The ultrasonic image observation apparatus 100 transmits an ultrasonic wave (ultrasonic signal) from the ultrasonic probe 2 to a not-illustrated subject, for example, the abdomen of a pregnant woman, and reflects the ultrasonic wave reflected from the inside of the subject. The state of the fetus in the subject is imaged as an ultrasound image from the reflected wave (echo, ultrasound signal) and displayed on the display unit 10.
　入力部１３は、超音波画像観察装置１００の電源を投入する電源スイッチや、例えばキーボード、タッチパネルなどの入力手段から構成されている。 The input unit 13 includes a power switch for turning on the ultrasonic image observation apparatus 100 and input means such as a keyboard and a touch panel.
　制御部９９は、ＣＰＵ９８（中央処理装置）と記憶部９６等から構成され、記憶部９６に記憶されているプログラムをＲＡＭ（Ｒａｎｄｏｍ　Ａｃｃｅｓｓ　Ｍｅｍｏｒｙ）に読み出し、当該プログラムに従って超音波画像観察装置１００の各部を制御する。記憶部９６は、ＲＡＭ（Ｒａｎｄｏｍ　Ａｃｃｅｓｓ　Ｍｅｍｏｒｙ）、ＲＯＭ（Ｒｅａｄ　Ｏｎｌｙ　Ｍｅｍｏｒｙ）、ハードディスク等から構成される。 The control unit 99 includes a CPU 98 (central processing unit), a storage unit 96, and the like, reads a program stored in the storage unit 96 into a RAM (Random Access Memory), and each unit of the ultrasonic image observation apparatus 100 according to the program. To control. The storage unit 96 includes a RAM (Random Access Memory), a ROM (Read Only Memory), a hard disk, and the like.
　超音波探触子２は、図示せぬ被検体に対して超音波を送波し、被検体で反射した超音波の反射波を受信する。超音波探触子２は、図１に示すように、送信処理部１、受信処理部３と電気的に接続されている。 The ultrasonic probe 2 transmits an ultrasonic wave to a subject (not shown) and receives a reflected wave of the ultrasonic wave reflected by the subject. As shown in FIG. 1, the ultrasound probe 2 is electrically connected to a transmission processing unit 1 and a reception processing unit 3.
　超音波探触子２は、送信処理部１から送信された送信信号によって超音波を送波する。 The ultrasonic probe 2 transmits ultrasonic waves by the transmission signal transmitted from the transmission processing unit 1.
　図２、図３を用いて、実施形態の送信処理部１の一例を説明する。 An example of the transmission processing unit 1 according to the embodiment will be described with reference to FIGS.
　送信処理部１は、タイミング信号発生部２５、符号選択部２６、符号記憶部２３、ＰＳＫ変調部２２、ＦＬＴ２９、送波アンプ２１を備える。 The transmission processing unit 1 includes a timing signal generation unit 25, a code selection unit 26, a code storage unit 23, a PSK modulation unit 22, an FLT 29, and a transmission amplifier 21.
　タイミング信号発生部２５は、制御部９９の指令により送信処理部１の各部にタイミングクロックを供給する。 The timing signal generation unit 25 supplies a timing clock to each unit of the transmission processing unit 1 according to a command from the control unit 99.
　符号選択部２６は、制御部９９の指令により符号記憶部２３に格納されている符号化の次数が複数種類の変調符号のうち何れか一つを選択する。医師など操作者は、入力部１３から操作することにより符号選択部２６が選択する変調符号の種類を設定することができる。 The code selection unit 26 selects any one of a plurality of types of modulation codes having the encoding order stored in the code storage unit 23 according to a command from the control unit 99. An operator such as a doctor can set the type of modulation code selected by the code selection unit 26 by operating from the input unit 13.
　符号記憶部２３には、互いに符号が反転関係にある少なくとも１組の変調符号が予め格納されている。変調符号は、公知のＢａｒｋｅｒ符号であり、所定の符号化の次数のＢａｒｋｅｒ符号の組み合わせである変調符号が予め符号記憶部２３に格納されている。 The code storage unit 23 stores in advance at least one set of modulation codes whose codes are in an inverted relationship. The modulation code is a known Barker code, and a modulation code that is a combination of Barker codes of a predetermined encoding order is stored in the code storage unit 23 in advance.
　図３は、符号記憶部２３に格納されている互いに符号が反転関係にある１組のＢａｒｋｅｒ符号の例である。図３は符号化の次数が５次のＢａｒｋｅｒ符号の例であり、（＋１、＋１、＋１、－１、＋１）の部分が第１の送信信号、これに続く（－１、－１、－１、＋１、－１）の部分が第１の送信信号を反転した第２の送信信号である。このように符号記憶部２３から第１の送信信号と第２の送信信号が順に出力される。 FIG. 3 is an example of a set of Barker codes stored in the code storage unit 23 and whose codes are in an inverted relationship with each other. FIG. 3 shows an example of a Barker code with a 5th-order encoding. The (+1, +1, +1, −1, +1) portion is the first transmission signal, followed by (−1, −1, − 1, +1, −1) are second transmission signals obtained by inverting the first transmission signal. As described above, the first transmission signal and the second transmission signal are sequentially output from the code storage unit 23.
　符号選択部２６は、この変調符号が格納されている符号記憶部２３のアドレスを指定し、所定の時間間隔Ｔで出力するよう制御する。 The code selection unit 26 controls the output of the code storage unit 23 storing the modulation code at a predetermined time interval T by designating the address.
　ＰＳＫ（Ｐｈａｓｅ　Ｓｈｉｆｔ　Ｋｅｙｉｎｇ）変調部２２は、符号記憶部２３から出力された符号要素の係数＋１または－１に応じて、一定周波数の搬送波の位相を変化させて変調する。すなわち、基本波形（位相０°）と、基本波形に対して１８０°位相をずらした波形を出力する。ＰＳＫ変調を行うことにより狭い周波数帯域で多くの情報を伝送することができ、ノイズや信号の減衰に影響されにくくすることができる。 A PSK (Phase Shift Keying) modulation unit 22 modulates the phase of a carrier wave having a constant frequency according to the code element coefficient +1 or −1 output from the code storage unit 23. That is, a basic waveform (phase 0 °) and a waveform that is 180 ° out of phase with respect to the basic waveform are output. By performing PSK modulation, a large amount of information can be transmitted in a narrow frequency band and can be made less susceptible to noise and signal attenuation.
　ＦＬＴ２９は、送信信号の帯域を制限するバンドパスフィルタなどのフィルタである。ＦＬＴ２９の特性については後に詳しく説明する。 FLT 29 is a filter such as a band pass filter that limits the band of the transmission signal. The characteristics of the FLT 29 will be described in detail later.
　送波アンプ２１は、ＦＬＴ２９で帯域制限された第１の送信信号、第２の送信信号を増幅し、所望の基本周波数ｆ０の成分を有する駆動信号で超音波探触子２を駆動する。 Transmitting amplifier 21, a first transmission signal band-limited by FLT29, amplifies the second transmission signal, drives the ultrasonic probe 2 in the drive signal having a component of the desired fundamental frequency f 0.
　次に、受信時の信号処理について図１を用いて説明する。 Next, signal processing during reception will be described with reference to FIG.
　超音波探触子２から超音波を被検体に向けて送波した後、超音波探触子２に返ってきたエコーは、超音波探触子２に配列された図示せぬ圧電素子を機械的に振動させ、微弱な受信信号を発生させる。以下の説明では、第１の送信信号によって送波した超音波に対応する受信信号を第１の受信信号、第２の送信信号によって送波した超音波に対応する受信信号を第２の受信信号と呼ぶ。 After transmitting ultrasonic waves from the ultrasonic probe 2 toward the subject, the echoes returned to the ultrasonic probe 2 are mechanically operated by piezoelectric elements (not shown) arranged in the ultrasonic probe 2. To generate a weak received signal. In the following description, the reception signal corresponding to the ultrasonic wave transmitted by the first transmission signal is the first reception signal, and the reception signal corresponding to the ultrasonic wave transmitted by the second transmission signal is the second reception signal. Call it.
　受信処理部３は、第１の受信信号、第２の受信信号を順に受信して所定の信号レベルに増幅した後、第１の受信信号と第２の受信信号にパルスインバージョンを行って基本波、または高調波の分散圧縮された成分を抽出し、伸張した後、包絡線検波を行った信号を出力する。受信処理部３で行う信号処理は、後に詳しく説明する。 The reception processing unit 3 receives the first reception signal and the second reception signal in order and amplifies them to a predetermined signal level, and then performs pulse inversion on the first reception signal and the second reception signal to perform basic processing. After the components of the wave or harmonics that have been distributed and compressed are extracted and expanded, a signal subjected to envelope detection is output. The signal processing performed by the reception processing unit 3 will be described in detail later.
　画像生成部６は、受信処理部３から出力された信号に基づいてＢモード画像を生成する。 The image generation unit 6 generates a B-mode image based on the signal output from the reception processing unit 3.
　画像処理部で画像処理された画像は、デジタルスキャンコンバータ（ＤＳＣ）９によってビデオ信号に変換され、表示部１０に表示される。 The image processed by the image processing unit is converted into a video signal by a digital scan converter (DSC) 9 and displayed on the display unit 10.
　なお、図３では送信処理部１の出力する変調符号の一例として符号化の次数が５のＢａｒｋｅｒ符号を説明したが、特にこの次数に限られるものではない。検出対象のコントラストに応じて最適な画像が得られる次数を設定すれば良い。 In FIG. 3, the Barker code with the encoding order of 5 is described as an example of the modulation code output from the transmission processing unit 1, but the order is not particularly limited to this order. What is necessary is just to set the order from which an optimal image is obtained according to the contrast of a detection target.
　次に、実施形態の送信処理部１の他の例について説明する。 Next, another example of the transmission processing unit 1 according to the embodiment will be described.
　図４は、実施形態の送信処理部１の他の例の詳細な回路ブロック図、図５は、本実施形態で生成するチャープ信号を説明する図である。 FIG. 4 is a detailed circuit block diagram of another example of the transmission processing unit 1 according to the embodiment, and FIG. 5 is a diagram illustrating a chirp signal generated in the present embodiment.
　コード生成部２７は、チャープ信号を生成する符号を予め記憶し、制御部９９からの指令により所定のクロックに従って記憶している符号を出力する。 The code generator 27 stores a code for generating a chirp signal in advance, and outputs the stored code in accordance with a predetermined clock according to a command from the controller 99.
　Ｄ／Ａ変換器２６は、コード生成部２７の順次出力する符号をアナログ信号に変換し出力する。図５は、生成されたチャープ信号を説明する図である。図中Ｔ１の期間が第１の送信信号であり、Ｔ２の期間が第１の送信信号を反転した第２の送信信号である。第１の送信信号と第２の送信信号は、時間とともに周波数が高くなるチャープ信号である。 The D / A converter 26 converts the code sequentially output from the code generation unit 27 into an analog signal and outputs the analog signal. FIG. 5 is a diagram for explaining the generated chirp signal. In the figure, a period T1 is a first transmission signal, and a period T2 is a second transmission signal obtained by inverting the first transmission signal. The first transmission signal and the second transmission signal are chirp signals whose frequency increases with time.
　ＦＬＴ２９は、送信信号の帯域を制限するバンドパスフィルタなどのフィルタである。ＦＬＴ２９の特性については後に詳しく説明する。 FLT 29 is a filter such as a band pass filter that limits the band of the transmission signal. The characteristics of the FLT 29 will be described in detail later.
　送波アンプ２１は、フィルタで帯域制限された第１の送信信号、第２の送信信号を増幅し、所望の基本周波数ｆ０の成分を有する駆動信号で超音波探触子２を駆動する。 Transmitting amplifier 21, a first transmission signal band-limited by filter, amplifies the second transmission signal, drives the ultrasonic probe 2 in the drive signal having a component of the desired fundamental frequency f 0.
　次に、本実施形態の受信処理について図６、図７を用いて説明する。 Next, the reception process of this embodiment will be described with reference to FIGS.
　図６は、第１の実施形態の受信処理部の電気的な構成を示すブロック図、図７は、第２の実施形態の受信処理部の電気的な構成を示すブロック図である。 FIG. 6 is a block diagram showing the electrical configuration of the reception processing unit of the first embodiment, and FIG. 7 is a block diagram showing the electrical configuration of the reception processing unit of the second embodiment.
　最初に図６の受信処理部３を説明する。 First, the reception processing unit 3 in FIG. 6 will be described.
　受信回路３１は、超音波探触子２が出力する第１の受信信号と第２の受信信号を順に受信して所定の信号レベルに増幅する。増幅された信号は、Ａ／Ｄ変換器３２によりデジタル値に変換される。 The reception circuit 31 sequentially receives the first reception signal and the second reception signal output from the ultrasound probe 2 and amplifies them to a predetermined signal level. The amplified signal is converted into a digital value by the A / D converter 32.
　遅延部３３は、例えばラインメモリであり、第１の受信信号を第１の受信信号の送信を開始した時間と前記第２の受信信号の送信を開始した時間の時間差に相当する間遅延させる。Ａ／Ｄ変換器３２の出力は遅延部３３に入力され、第１の受信信号を該時間差に相当する間遅延して減算器３４に入力する。 The delay unit 33 is, for example, a line memory, and delays the first reception signal for a time corresponding to the time difference between the time when transmission of the first reception signal is started and the time when transmission of the second reception signal is started. The output of the A / D converter 32 is input to the delay unit 33, and the first received signal is delayed for a time corresponding to the time difference and input to the subtractor 34.
　減算器３４は、遅延部３３の入力信号と遅延部３３の出力信号とを減算する。前述のように遅延部３３で第１の受信信号は遅延されるので、減算器３４には第１の受信信号と第２の受信信号とが同時に入力され、第１の受信信号と第２の受信信号の差分が減算器３４から差分信号として出力される。 The subtracter 34 subtracts the input signal of the delay unit 33 and the output signal of the delay unit 33. Since the first reception signal is delayed by the delay unit 33 as described above, the first reception signal and the second reception signal are simultaneously input to the subtractor 34, and the first reception signal and the second reception signal are input. The difference between the received signals is output from the subtracter 34 as a difference signal.
　差分信号には、第１の受信信号と第２の受信信号で同位相の２次高調波２ｆ０の成分が減算することにより除去され、第１の受信信号と第２の受信信号とで逆位相の基本周波数ｆ０の成分と３次高調波３ｆ０の成分が残っている。 The difference signal is removed by subtracting the component of the second harmonic 2f 0 having the same phase between the first received signal and the second received signal, and the first received signal and the second received signal are reversed. remaining ingredients and components of the third harmonic 3f 0 of the fundamental frequency f 0 of the phase.
　差分信号は、基本波ＬＰＦ（ローパスフィルタ）３６と３次高調波ＢＰＦ（バンドパスフィルタ）３５とに入力され、基本周波数ｆ０の成分と３次高調波３ｆ０の成分に分離される。 Differential signal is inputted to the fundamental wave LPF (low pass filter) 36 and the third harmonic BPF (band pass filter) 35 is separated into components of the component of the fundamental frequency f 0 and the third-order harmonic 3f 0.
　基本波ＬＰＦ３６は、主に減算器３４の出力に含まれる超音波探触子２の送波する超音波の基本周波数ｆ０とその側帯波の帯域を通過させる。３次高調波ＢＰＦ３５は、主に減算器３４の出力に含まれる超音波探触子２の送波する超音波の３次高調波３ｆ０とその側帯波の帯域を通過させる。 The fundamental wave LPF 36 mainly passes the fundamental frequency f 0 of the ultrasonic wave transmitted by the ultrasonic probe 2 included in the output of the subtractor 34 and the sideband band thereof. The third harmonic BPF 35 mainly passes the band of the third harmonic 3f 0 of the ultrasonic wave transmitted by the ultrasonic probe 2 included in the output of the subtractor 34 and its sideband.
　ＳＷ（スイッチ）３７は、制御部９９の指令により基本波ＬＰＦ３６、または３次高調波ＢＰＦ３５の出力を切り替えて不整合フィルタ（復調フィルタ）３９に出力する。 The SW (switch) 37 switches the output of the fundamental wave LPF 36 or the third harmonic BPF 35 in accordance with a command from the control unit 99 and outputs it to the mismatch filter (demodulation filter) 39.
　不整合フィルタ３９は、ＦＩＲフィルタ等により構成され、送信処理部１の生成した変調信号に対応する係数を予め保持し、受信した分散圧縮されている信号を伸張する。 The mismatch filter 39 is configured by an FIR filter or the like, holds a coefficient corresponding to the modulation signal generated by the transmission processing unit 1 in advance, and expands the received dispersion-compressed signal.
　例えば、送信処理部１の生成した変調符号がＢａｒｋｅｒ符号の場合であれば、超音波送信時に制御部９９から、Ｂａｒｋｅｒ符号の係数を時間軸について反転させた不整合フィルタ係数が不整合フィルタ３９に設定される。不整合フィルタ係数は、ピーク値をできるだけ保ちながらサイドローブを最小化するように決定された係数の大きさが１ではない係数である。不整合フィルタ３９は、受信した信号の値と不整合フィルタ係数との積和演算を行って伸張する。 For example, if the modulation code generated by the transmission processing unit 1 is a Barker code, the mismatch filter coefficient obtained by inverting the coefficient of the Barker code with respect to the time axis is supplied to the mismatch filter 39 from the control unit 99 during ultrasonic transmission. Is set. The mismatch filter coefficient is a coefficient whose coefficient magnitude is determined not to be 1 so as to minimize the side lobe while keeping the peak value as much as possible. The mismatch filter 39 performs a product-sum operation on the received signal value and the mismatch filter coefficient, and expands the result.
　包絡線検波部４０は、不整合フィルタ３９の出力を検波し、検波出力を画像生成部６に出力する。 The envelope detection unit 40 detects the output of the mismatch filter 39 and outputs the detection output to the image generation unit 6.
　図６の受信処理部３の説明は以上である。 The description of the reception processing unit 3 in FIG.
　次に図７の受信処理部３を説明する。 Next, the reception processing unit 3 in FIG. 7 will be described.
　図７の受信処理部３は、遅延部３３の入力信号と遅延部３３の出力信号とを加算器４１を有する点が図６の受信処理部３と異なる。その他の構成要素は図６と同じであり、同じ機能の構成要素には同番号を付し、説明を省略する。 7 is different from the reception processing unit 3 in FIG. 6 in that an adder 41 is provided between the input signal of the delay unit 33 and the output signal of the delay unit 33. The other components are the same as those in FIG. 6, and the components having the same functions are denoted by the same reference numerals and description thereof is omitted.
　前述のように遅延部３３で第１の受信信号は遅延されるので、遅延部３３には第１の受信信号と第２の受信信号とが同時に入力され、第１の受信信号と第２の受信信号が加算された和信号が出力される。 As described above, since the first reception signal is delayed by the delay unit 33, the first reception signal and the second reception signal are simultaneously input to the delay unit 33, and the first reception signal and the second reception signal are input. A sum signal obtained by adding the received signals is output.
　和信号には、第１の受信信号と第２の受信信号で逆位相の基本周波数ｆ０の成分と３次高調波３ｆ０の成分が加算することにより除去され、第１の受信信号と第２の受信信号とで同位相の２次高調波２ｆ０の成分が残っている。 The sum signal is removed by the components of the first received signal and the component and the third harmonic 3f 0 of the fundamental frequency f 0 of the opposite phase with the second reception signal is added, the first received signal and the The second harmonic 2f 0 component remains in phase with the received signal 2.
　和信号は、２次高調波ＢＰＦ（バンドパスフィルタ）４２に入力され、２次高調波２ｆ０の成分が分離される。 The sum signal is input to the second harmonic wave BPF (band pass filter) 42, the component of the second harmonic 2f 0 is separated.
　ＳＷ３７は、制御部９９の指令により基本波ＬＰＦ３６、２次高調波ＢＰＦ４２、または３次高調波ＢＰＦ３５の出力を切り替えて不整合フィルタ３９に出力する。 SW 37 switches the output of the fundamental wave LPF 36, the second harmonic BPF 42, or the third harmonic BPF 35 according to a command from the control unit 99, and outputs it to the mismatch filter 39.
　なお、この例に限らず、基本波ＬＰＦ３６、２次高調波ＢＰＦ４２、または３次高調波ＢＰＦ３５の何れか一つを備え、ＳＷ３７による切り替えを行わない構成や、２次高調波ＢＰＦ４２と３次高調波ＢＰＦ３５の２つを切り替える構成などでも良い。 Not limited to this example, any one of the fundamental wave LPF 36, the second harmonic BPF 42, or the third harmonic BPF 35 is provided, and the switching by the SW 37 is not performed, and the second harmonic BPF 42 and the third harmonic are not switched. A configuration in which two of the waves BPF 35 are switched may be used.
　このように、本実施形態では互いに位相が反転関係にある超音波の組を送波し、この超音波の組のうち一方に対応する受信信号と、他方に対応する受信信号の差分信号または和信号を算出してｎ次の高調波成分を抽出することができる。 As described above, in the present embodiment, a pair of ultrasonic waves whose phases are inverted with respect to each other is transmitted, and a difference signal or a sum of a reception signal corresponding to one of the ultrasonic waves and a reception signal corresponding to the other is transmitted. The signal can be calculated to extract the nth-order harmonic component.
　次に、これまで実施形態で説明したパルスインバージョンの信号処理を行う際に、所定の次数の高調波を抽出するため基本波と３次高調波のスペクトラムを重ならないようにする条件を説明する。 Next, when performing the signal processing of the pulse inversion described in the embodiments so far, conditions for preventing the fundamental and third harmonics from overlapping the spectrum in order to extract the harmonics of a predetermined order will be described. .
　図８は、超音波探触子２から送波される超音波の周波数特性の一例を示すグラフ、図９は、加算または減算後の受信信号の周波数スペクトラムを説明する図である。 FIG. 8 is a graph showing an example of the frequency characteristic of the ultrasonic wave transmitted from the ultrasonic probe 2, and FIG. 9 is a diagram for explaining the frequency spectrum of the received signal after addition or subtraction.
　図中、ｆ０は超音波探触子２から送波される超音波の基本周波数、Ｇ０は基本周波数ｆ０における超音波の音圧の利得である。図８のように利得Ｇ０から３ｄＢ利得が低下する周波数はｆ１とｆ２である。したがって、ｆ１は周波数帯域の下限の周波数、ｆ２は周波数帯域の上限の周波数である。 In the figure, f 0 is the fundamental frequency of the ultrasonic wave transmitting from the ultrasound probe 2, G 0 is the gain of the ultrasonic sound pressure at the fundamental frequency f 0. As shown in FIG. 8, the frequencies at which the 3 dB gain decreases from the gain G 0 are f 1 and f 2 . Therefore, f 1 is the lower limit frequency of the frequency band, and f 2 is the upper limit frequency of the frequency band.
　また、図８に示すようにｆ２＜２ｆ０であり、２次高調波の周波数であるｆ０の２倍の２ｆ０より高い周波数成分は十分減衰されている。 Further, as shown in FIG. 8, f 2 <2f 0 , and the frequency component higher than 2f 0 which is twice the frequency of f 0 which is the frequency of the second harmonic is sufficiently attenuated.
　例えば、ｆ０が３ＭＨｚの場合、ｆ１を１ＭＨｚ、ｆ２を５ＭＨｚにすると良い。２ｆ０は６ＭＨｚであり、ｆ２＜２ｆ０の条件を満たすので、２次高調波である６ＭＨｚと３次高調波とを抽出することが可能になる。 For example, when f 0 is 3 MHz, f 1 may be 1 MHz and f 2 may be 5 MHz. Since 2f 0 is 6 MHz and satisfies the condition of f 2 <2f 0 , it is possible to extract 6 MHz and the third harmonic, which are second harmonics.
　このような超音波探触子２から送波される超音波の周波数特性は、例えば送信処理部のＦＬＴ２９を図８のような周波数特性のバンドパスフィルタにして帯域制限することで実現できる。 Such a frequency characteristic of the ultrasonic wave transmitted from the ultrasonic probe 2 can be realized, for example, by limiting the band by using the FLT 29 of the transmission processing unit as a bandpass filter having a frequency characteristic as shown in FIG.
　なお、超音波探触子２の圧電素子や送波アンプ２１の周波数帯域が十分広い場合は、主にＦＬＴ２９により周波数帯域が決定されるが、これらの周波数帯域が狭い場合は、圧電素子の周波数特性や送波アンプ２１の特性など総合特性を考慮して設定することが望ましい。 If the frequency band of the piezoelectric element of the ultrasonic probe 2 or the transmission amplifier 21 is sufficiently wide, the frequency band is mainly determined by the FLT 29. If these frequency bands are narrow, the frequency of the piezoelectric element is determined. It is desirable to set in consideration of the overall characteristics such as the characteristics and the characteristics of the transmission amplifier 21.
　図９（ａ）は、図８に示す周波数特性の超音波を送波した場合の受信信号を減算器３４で減算した出力例であり、図９（ｂ）は加算器４１の出力例である。図９（ａ）では、減算後の差分信号に残った基本周波数の成分５１と３次高調波の成分５３が実線で示され、除去された２次高調波の成分５２が点線で表示されている。図９（ｂ）は、加算後の和信号に残った２次高調波の成分５２が実線で示され、除去された基本周波数の成分５１と３次高調波の成分５３が点線で表示されている。 FIG. 9A shows an output example obtained by subtracting the reception signal when the ultrasonic wave having the frequency characteristic shown in FIG. 8 is transmitted by the subtractor 34, and FIG. 9B is an output example of the adder 41. . In FIG. 9A, the fundamental frequency component 51 and the third harmonic component 53 remaining in the difference signal after subtraction are indicated by a solid line, and the removed second harmonic component 52 is indicated by a dotted line. Yes. In FIG. 9B, the second harmonic component 52 remaining in the sum signal after addition is indicated by a solid line, and the removed fundamental frequency component 51 and third harmonic component 53 are indicated by a dotted line. Yes.
　送波時の超音波の周波数帯域は図８のように制限されているので、図９（ａ）のように受信信号の基本周波数の成分５１はｆ０を中心にｆ０の２倍の周波数２ｆ０より低い周波数の範囲に分布している。また、受信信号の３次高調波の成分５３はｆ０の３倍の周波数３ｆ０を中心に２ｆ０より高い周波数の範囲に分布している。また、２次高調波の成分５２のエネルギーの大きい２ｆ０付近の成分と重なる部分が少ない。 Since ultrasonic frequency band when transmitting is limited as shown in Figure 8, the frequency of two times f 0 component 51 of the fundamental frequency of the received signal around the f 0 as shown in FIG. 9 (a) 2f is distributed in a frequency range lower than 0 . The third-harmonic component 53 of the received signal is distributed in a frequency range higher than 2f 0 around a frequency 3f 0 that is three times f 0 . In addition, there are few portions that overlap with components near 2f 0 where the energy of the second harmonic component 52 is large.
　このように、基本周波数の成分５１と３次高調波の成分５３は周波数帯域が重なっていないのでパルスインバージョンを用いて、図９（ａ）のように減算後は２次高調波の成分５２を除去し、基本周波数の成分５１と３次高調波の成分５３を残すことができる。また、この後、基本波ＬＰＦ３６と３次高調波ＢＰＦ３５を通過させることにより、容易に基本周波数の成分５１と３次高調波の成分５３を分離できる。 Thus, since the frequency band of the fundamental frequency component 51 and the third harmonic component 53 do not overlap, the second harmonic component 52 after subtraction as shown in FIG. 9A using pulse inversion. The fundamental frequency component 51 and the third harmonic component 53 can be left. Thereafter, the fundamental frequency component 51 and the third harmonic component 53 can be easily separated by passing the fundamental LPF 36 and the third harmonic BPF 35.
　同様に、基本周波数の成分５１と３次高調波の成分５３は周波数帯域が重なっていないのでパルスインバージョンを用いて、図９（ｂ）のように加算後は基本周波数の成分５１と３次高調波の成分５３を除去し、２次高調波の成分５２を残すことができる。また、この後、２次高調波ＢＰＦ４２を通過させることにより、容易に２次高調波の成分５２を分離できる。 Similarly, since the fundamental frequency component 51 and the third harmonic component 53 do not overlap in frequency band, using the pulse inversion, the fundamental frequency component 51 and the third order component are added as shown in FIG. 9B. The harmonic component 53 can be removed, and the second harmonic component 52 can be left. Thereafter, the second harmonic component 52 can be easily separated by passing the second harmonic BPF 42.
　なお、基本周波数ｆ０より低い周波数成分はできるだけ広い周波数範囲で残すと伸張後の信号レベルを大きくすることができる。 If the frequency component lower than the fundamental frequency f 0 is left in the widest possible frequency range, the signal level after expansion can be increased.
　例えば、図１０のように送波する超音波の周波数特性を（ｆ０－ｆ１）＞（ｆ２－ｆ０）になるようにすれば良い。図１０は、超音波探触子２から送波される超音波の周波数特性の別例を示すグラフである。 For example, as shown in FIG. 10, the frequency characteristics of the ultrasonic wave to be transmitted may be set to (f 0 −f 1 )> (f 2 −f 0 ) FIG. 10 is a graph showing another example of frequency characteristics of ultrasonic waves transmitted from the ultrasonic probe 2.
　例えば、ｆ０が３ＭＨｚの場合、ｆ１を０．５ＭＨｚ、ｆ２を４ＭＨｚにすると良い。ｆ０－ｆ１は２．５ＭＨｚ、ｆ２－ｆ０は１ＭＨｚであり、（ｆ０－ｆ１）＞（ｆ２－ｆ０）の条件を満たしている。 For example, when f 0 is 3 MHz, f 1 may be 0.5 MHz and f 2 may be 4 MHz. f 0 -f 1 is 2.5 MHz, and f 2 -f 0 is 1 MHz, which satisfies the condition (f 0 -f 1 )> (f 2 -f 0 ).
　また、超音波は高い周波数ほど被検体で減衰しやすいので、送信時に高い周波数ほど利得が高くなるようにしておくことが望ましい。例えば、図１１のように超音波探触子２から送波される超音波の周波数特性を、基本周波数ｆ０より周波数が高くなるにつれて基本周波数ｆ０の利得Ｇ０より利得が増加し、基本周波数ｆ０より周波数が低くなるにつれて利得Ｇ０より利得が減少する周波数範囲を有するようにすれば良い。図１１の周波数特性例では、ｆ０を含むｆ１からｆＢの間で利得が周波数に比例して増加している。 Further, since ultrasonic waves are more likely to be attenuated by the subject at higher frequencies, it is desirable to increase the gain at higher frequencies during transmission. For example, the ultrasonic frequency characteristic transmitting from the ultrasound probe 2 as shown in FIG. 11, increased gain than the gain G 0 of the fundamental frequency f 0 as the frequency becomes higher than the fundamental frequency f 0, the basic A frequency range in which the gain decreases from the gain G 0 as the frequency becomes lower than the frequency f 0 may be provided. In the frequency characteristic example of FIG. 11, the gain increases in proportion to the frequency between f 1 and f B including f 0 .
　例えば、ｆ０が３ＭＨｚ、ｆ１を１ＭＨｚ、ｆ２を５ＭＨｚとするとｆＢ＝４．５ＭＨｚになるように構成すれば良い。 For example, if f 0 is 3 MHz, f 1 is 1 MHz, and f 2 is 5 MHz, f B = 4.5 MHz may be configured.
　このようにすると、高い周波数でも大きな受信信号が得られ、伸張後の信号レベルを大きくすることができる。 In this way, a large received signal can be obtained even at a high frequency, and the signal level after expansion can be increased.
　以上このように、本発明によれば、分散圧縮による送受信を用いて対象とするｎ次高調波を抽出することができる。 As described above, according to the present invention, it is possible to extract a target n-order harmonic using transmission and reception by distributed compression.
　１　送信処理部
　２　超音波探触子
　３　受信処理部
　６　画像生成部
　９　デジタルスキャンコンバータ
　１０　表示部
　１３　入力部
　３１　受信回路
　３２　Ａ／Ｄ変換器
　３３　遅延部
　３４　減算器
　３５　３次高調波ＢＰＦ
　３６　基本波ＬＰＦ
　３９　不整合フィルタ
　４１　加算器
　４２　２次高調波ＢＰＦ
　９６　記憶部
　９８　ＣＰＵ
　９９　制御部
　１００　超音波診断装置 DESCRIPTION OF SYMBOLS 1 Transmission processing part 2 Ultrasonic probe 3 Reception processing part 6 Image generation part 9 Digital scan converter 10 Display part 13 Input part 31 Reception circuit 32 A / D converter 33 Delay part 34 Subtractor 35 3rd harmonic BPF
36 fundamental wave LPF
39 Mismatch filter 41 Adder 42 Second harmonic BPF
96 storage unit 98 CPU
99 Control unit 100 Ultrasonic diagnostic apparatus

Claims (9)

  1. 　被検体に超音波を送波する超音波探触子と、所望の基本周波数の成分を有する分散圧縮した第１の送信信号と前記第１の送信信号を反転した第２の送信信号とを順に生成して超音波探触子を駆動する送信処理部と、前記超音波探触子が受信した前記第１の送信信号に対応する第１の受信信号と前記第２の送信信号に対応する第２の受信信号との差分信号または和信号の少なくとも一方を伸張して出力する受信処理部と、前記受信処理部の出力する伸張された信号を用いて超音波画像を生成する画像生成部と、前記画像生成部で生成された超音波画像を表示する表示部と、を備えた超音波診断装置であって、
    　前記超音波探触子から送波される超音波の基本周波数をｆ０、周波数帯域の上限の周波数をｆ２とすると、ｆ２＜２ｆ０になるように構成されていることを特徴とする超音波診断装置。     An ultrasonic probe that transmits ultrasonic waves to the subject, a first transmission signal that is distributed and compressed having a component of a desired fundamental frequency, and a second transmission signal that is an inversion of the first transmission signal, in this order. A transmission processing unit that generates and drives the ultrasound probe; a first reception signal that corresponds to the first transmission signal that is received by the ultrasound probe; and a second signal that corresponds to the second transmission signal. A reception processing unit that expands and outputs at least one of a difference signal or a sum signal from the received signal of 2; an image generation unit that generates an ultrasonic image using the expanded signal output from the reception processing unit; A display unit for displaying an ultrasonic image generated by the image generation unit, and an ultrasonic diagnostic apparatus comprising:
    When the fundamental frequency of the ultrasonic wave transmitted from the ultrasonic probe is f 0 , and the upper limit frequency of the frequency band is f 2 , f 2 <2f 0 is satisfied. Ultrasonic diagnostic equipment.
  2. 　周波数帯域の下限の周波数をｆ１とすると、（ｆ０－ｆ１）＞（ｆ２－ｆ０）であることを特徴とする請求項１に記載の超音波診断装置。 2. The ultrasonic diagnostic apparatus according to claim 1, wherein (f 0 −f 1 )> (f 2 −f 0 ), where f 1 is a lower limit frequency of the frequency band.
  3. 　前記超音波探触子から送波される超音波の音圧の利得は、
    　基本周波数ｆ０より周波数が高くなるにつれて増加し、基本周波数ｆ０より周波数が低くなるにつれて減少する周波数範囲を有することを特徴とする請求項１または２に記載の超音波診断装置。     The gain of the sound pressure of the ultrasonic wave transmitted from the ultrasonic probe is
    Increases as the frequency than the fundamental frequency f 0 is higher, the ultrasonic diagnostic apparatus according to claim 1 or 2, characterized in that it has a frequency range decreases as the frequency than the fundamental frequency f 0 is lowered.
  4. 　前記受信処理部は、
    　前記第１の受信信号の送信を開始した時間と前記第２の受信信号の送信を開始した時間の時間差に相当する間、前記第１の受信信号を遅延させる遅延部と、
    　前記遅延部の出力と、前記第２の受信信号との差分を前記差分信号として算出する減算器と、
    　を有することを特徴とする請求項１から３の何れか１項に記載の超音波診断装置。     The reception processing unit
    A delay unit that delays the first reception signal for a time difference between a time at which transmission of the first reception signal is started and a time at which transmission of the second reception signal is started;
    A subtractor that calculates a difference between the output of the delay unit and the second received signal as the difference signal;
    The ultrasonic diagnostic apparatus according to any one of claims 1 to 3, wherein:
  5. 　前記受信処理部は、
    　前記第１の受信信号の送信を開始した時間と前記第２の受信信号の送信を開始した時間の時間差に相当する間、前記第１の受信信号を遅延させる遅延部と、
    　前記遅延部の出力と、前記第２の受信信号との和を前記和信号として算出する加算器と、
    　を有することを特徴とする請求項１から４の何れか１項に記載の超音波診断装置。     The reception processing unit
    A delay unit that delays the first reception signal for a time difference between a time at which transmission of the first reception signal is started and a time at which transmission of the second reception signal is started;
    An adder that calculates the sum of the output of the delay unit and the second received signal as the sum signal;
    The ultrasonic diagnostic apparatus according to claim 1, comprising:
  6. 　前記受信処理部は、
    　前記差分信号または前記和信号について変調符号列による分散圧縮を伸張する復調フィルタと、
    　前記復調フィルタによって伸張された信号の包絡線を検波して出力する包絡線検波部と、
    　を有することを特徴とする請求項４または５に記載の超音波診断装置。     The reception processing unit
    A demodulation filter for expanding distributed compression by a modulation code string for the differential signal or the sum signal;
    An envelope detector for detecting and outputting an envelope of the signal expanded by the demodulation filter;
    The ultrasonic diagnostic apparatus according to claim 4, wherein:
  7. 　前記送信処理部は、
    　互いに符号が反転関係にある１組のＢａｒｋｅｒ符号を前記第１の送信信号および前記第２の送信信号として生成することを特徴とする請求項４から６の何れか１項に記載の超音波診断装置。     The transmission processing unit
    The ultrasonic diagnosis according to any one of claims 4 to 6, wherein a set of Barker codes whose signs are inverted to each other are generated as the first transmission signal and the second transmission signal. apparatus.
  8. 　前記送信処理部は、
    　前記第１の送信信号および前記第２の送信信号にＰＳＫ変調を行って出力することを特徴とする請求項７に記載の超音波診断装置。     The transmission processing unit
    The ultrasonic diagnostic apparatus according to claim 7, wherein the first transmission signal and the second transmission signal are subjected to PSK modulation and output.
  9. 　前記送信処理部は、
    　互いに位相が反転関係にある１組のチャープ信号を前記第１の送信信号および前記第２の送信信号として生成することを特徴とする請求項４から６の何れか１項に記載の超音波診断装置。     The transmission processing unit
    The ultrasonic diagnosis according to any one of claims 4 to 6, wherein a set of chirp signals having a phase inversion relationship with each other is generated as the first transmission signal and the second transmission signal. apparatus.
PCT/JP2010/067413 2009-10-23 2010-10-05 Ultrasound diagnosis apparatus WO2011048939A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2011537196A JP5692083B2 (en) 2009-10-23 2010-10-05 Ultrasonic diagnostic equipment

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2009244202 2009-10-23
JP2009-244202 2009-10-23

Publications (1)

Publication Number Publication Date
WO2011048939A1 true WO2011048939A1 (en) 2011-04-28

Family

ID=43900171

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2010/067413 WO2011048939A1 (en) 2009-10-23 2010-10-05 Ultrasound diagnosis apparatus

Country Status (2)

Country Link
JP (1) JP5692083B2 (en)
WO (1) WO2011048939A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2014147620A (en) * 2013-02-04 2014-08-21 Seiko Epson Corp Ultrasonic measurement apparatus, ultrasonogram apparatus, and ultrasonic measurement method

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5710512A (en) * 1980-06-20 1982-01-20 Fujitsu Ltd Equalizing circuit
JPH09187457A (en) * 1996-01-12 1997-07-22 Ge Yokogawa Medical Syst Ltd Ultrasonic photographing method and apparatus therefor
JP2004520907A (en) * 2001-01-11 2004-07-15 ゼネラル・エレクトリック・カンパニイ Harmonic Golay coded excitation with differential pulse generation for diagnostic ultrasound imaging
JP2005211334A (en) * 2004-01-29 2005-08-11 Aloka Co Ltd Ultrasonic diagnosis equipment

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5710512A (en) * 1980-06-20 1982-01-20 Fujitsu Ltd Equalizing circuit
JPH09187457A (en) * 1996-01-12 1997-07-22 Ge Yokogawa Medical Syst Ltd Ultrasonic photographing method and apparatus therefor
JP2004520907A (en) * 2001-01-11 2004-07-15 ゼネラル・エレクトリック・カンパニイ Harmonic Golay coded excitation with differential pulse generation for diagnostic ultrasound imaging
JP2005211334A (en) * 2004-01-29 2005-08-11 Aloka Co Ltd Ultrasonic diagnosis equipment

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2014147620A (en) * 2013-02-04 2014-08-21 Seiko Epson Corp Ultrasonic measurement apparatus, ultrasonogram apparatus, and ultrasonic measurement method

Also Published As

Publication number Publication date
JPWO2011048939A1 (en) 2013-03-07
JP5692083B2 (en) 2015-04-01

Similar Documents

Publication Publication Date Title
JP5570877B2 (en) Ultrasonic diagnostic equipment
US7037265B2 (en) Method and apparatus for tissue harmonic imaging with natural (tissue) decoded coded excitation
JP4405182B2 (en) Ultrasonic diagnostic equipment
JP2017055845A (en) Ultrasonic diagnostic device and signal processing device
JP3959257B2 (en) Ultrasonic diagnostic equipment
US20100137715A1 (en) Ultrasonic imaging apparatus and control method for ultrasonic imaging apparatus
JP5692083B2 (en) Ultrasonic diagnostic equipment
JP4698003B2 (en) Ultrasonic diagnostic equipment
JP2010051375A (en) Ultrasonic image forming apparatus and ultrasonic image forming method
JP2003265466A (en) Ultrasonograph
US10064601B2 (en) Ultrasonic diagnostic apparatus, image processing apparatus, and image processing method
JP5423310B2 (en) Ultrasonic diagnostic equipment
KR101310930B1 (en) Medical Diagnostic Apparatus
JP4627675B2 (en) Ultrasonic diagnostic equipment
JP2013063159A (en) Ultrasonograph and ultrasonic image generation method
JP4469836B2 (en) Ultrasonic diagnostic equipment
JP2009261436A (en) Ultrasonic diagnostic apparatus
JP2005211334A (en) Ultrasonic diagnosis equipment
JP7171933B2 (en) Acoustic probe and control method for acoustic probe
US20170224310A1 (en) Ultrasonic diagnostic apparatus and ultrasonic signal processing method
JP4769840B2 (en) Ultrasonic diagnostic equipment
JP4719765B2 (en) Ultrasonic diagnostic equipment
JP2010268945A (en) Ultrasonograph
JP6504297B2 (en) Ultrasonic diagnostic equipment
JP4551908B2 (en) Ultrasonic diagnostic equipment

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 10824788

Country of ref document: EP

Kind code of ref document: A1

WWE Wipo information: entry into national phase

Ref document number: 2011537196

Country of ref document: JP

122 Ep: pct application non-entry in european phase

Ref document number: 10824788

Country of ref document: EP

Kind code of ref document: A1