JP2001276070A - Ultrasonic doppler diagnostic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ultrasonic Doppler diagnostic device which simultaneously executes the measurement of blood velocities relating to a plurality of areas distributed to the two-dimensional lane within an organism at different reference frequencies. SOLUTION: This ultrasonic Doppler diagnostic device has transmission trigger pulse signal generating means (21, 31a and 31b) which simultaneously form transmission trigger pulse signals of different frequencies, transmission delay control means (32a and 32b) which independently delay and control the respective transmission trigger pulse signals, transmitting means (33a, 33b and 34) which simultaneously transmit the transmission signals of high voltages of the different frequencies in superposition, receiving means (51) which receives ultrasonic echoes, band-pass filters (52a and 52b) which vary in pass frequency bands, reception delay control means (53a and 53b) which independently delay and control the respective reception signals varying in the frequency bands, phase detecting means (61a, 54a and 54b) which detect phases at the reference frequencies different from each other and blood velocity computing means (71) which computes the blood velocities from the detection signals.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic probe for transmitting ultrasonic waves from a group of ultrasonic probes into a living body, detecting a Doppler shift frequency generated in an ultrasonic echo from a blood flow, and measuring a blood flow velocity. Ultrasonic Doppler diagnostic apparatus, in particular, an ultrasonic Doppler diagnostic apparatus capable of detecting the phase of an ultrasonic echo signal in a living body by phase detection means, calculating the blood flow velocity in the living body from the phase, and displaying the calculation result About.

[0002]

2. Description of the Related Art Ultrasound diagnostics of the circulatory system for the purpose of diagnosing cardiac functions include a B-mode function, a M-mode function, and a FFT pulse Doppler, which are the main functions of a current general-purpose ultrasonic Doppler diagnostic apparatus. Function and the results of the blood flow velocity diagnosis using the color Doppler function. The B-mode function measures the major and minor axis diameters and cross-sectional areas of the ventricle from cross-sectional images of the heart. The M-mode function measures temporal changes such as ventricular diameter and septum thickness, FFT Doppler function and color Doppler function. The function mainly measures the blood flow velocity at the disease site.

[0003] If regurgitation is taken as an example of valvular disease, the regurgitation of blood at a diseased site is generally a high-speed blood flow and slow at the end of the reach of the regurgitation flow. It is necessary to switch the flow velocity measurement range. Generally, the maximum detection speed Vmax in the Doppler function of the ultrasonic Doppler diagnostic apparatus is proportional to the ultrasonic pulse repetition frequency PRF as given by Expression 1. (Equation 1) Here, C: speed of sound f _R : reference frequency θ: angle between blood flow and ultrasonic acoustic line On the other hand, since the maximum detection depth Dmax is inversely proportional to the ultrasonic pulse repetition frequency PRF of the apparatus, the maximum detection speed Vmax is in inverse proportion to Vmax. (Equation 2) To increase the maximum detection speed Vmax, the PRF may be set high.
Is increased, the maximum detection depth Dmax decreases.
When taking aortic regurgitation as an example of the valvular disease,
In general, scanning is performed from the apex, but the left ventricle is located closer to the ultrasound probe group than the aorta, and regurgitation leaking from the aortic valve flows into the left ventricle in the direction toward the ultrasound probe group. Distribute. At the site of regurgitation, a high-speed regurgitation occurs, and the velocity decreases as the position approaches the ultrasonic probe group. In the measurement of the blood flow velocity in this case, the ultrasonic repetition frequency PRF is set high in order to increase the maximum detection speed Vmax in a deep part away from the ultrasonic probe group. In some cases, measurement cannot be performed because of the contradictory decrease. For high-speed blood flow measurement, Dmax
HPRF (H
i-PRF) is often used. On the other hand, the back flow start tip from becoming a position to and slow blood flow in the vicinity of the ultrasonic probe group, a complicated operation of setting a high reference frequency f _R resets low PRF is required.

As described above, in measuring the backflow distribution from the insufficiency, the blood flow velocities at a plurality of sites are measured, but there is a demand to measure these at the same time.
However, in the pulse Doppler method of the current ultrasonic Doppler diagnostic apparatus, as described above, the ultrasonic pulse repetition frequency P
It is necessary to switch the RF and the reference frequency f _R complicatedly. At present, continuous Doppler measurement is often used for this purpose, but in principle, the distance resolution is poor or not at all, and the blood flow velocities of all parts existing on one ultrasonic acoustic line are mixed. Measured. Therefore, it is impossible to separately measure the blood flow velocity of each part, and since it is possible to measure only the blood flow velocity of the part located on the axis of the ultrasonic acoustic line, the blood flow in the part separated in the azimuth direction is measured. There is a problem that the flow velocity cannot be measured simultaneously.

On the other hand, in the invention reported in Japanese Patent Application Laid-Open No. H10-165400, it is possible to measure the blood flow distribution in a two-dimensional plane, but mainly for the movement velocity of the blood vessel wall or the plaque in the wall. In addition, since the velocity of movement at a separated site is measured by scanning the transmitted / received ultrasonic acoustic line in the azimuth direction, the measurement of the blood flow velocity at a part of the position actually causes a decrease in the PRF. There is a problem that flow is disadvantageous.

[0006]

In diagnosing valvular disease, there is a need to simultaneously measure blood flow velocities at a plurality of two-dimensionally distributed sites at different reference frequencies. That is, focusing on the product of Vmax and Dmax in the above equation 2, the product of Vmax and Dmax is increased in order to enable high-speed blood flow measurement in a deep part even from the example of aortic regurgitation. It is necessary to set a high PRF and lower the reference frequency f _R. On the other hand, the product of Vmax and Dmax can be reduced for a blood flow at a relatively low velocity near the ultrasonic probe group, so that the PR
The measurement frequency resolution can be increased by increasing the reference frequency f _R without changing the setting of F. Accordingly, if a plurality of (at least two) ultrasonic acoustic lines can be formed at different reference frequencies f _R , it is possible to simultaneously measure a plurality of blood flow velocities.

SUMMARY OF THE INVENTION The present invention solves such a problem, and an ultrasonic Doppler diagnosis capable of simultaneously measuring blood flow velocities from a plurality of two-dimensionally distributed portions in a living body at different reference frequencies. It is intended to provide a device.

[0008]

According to the present invention, an ultrasonic probe is transmitted into a living body from an ultrasonic probe group, and a Doppler shift frequency generated in an ultrasonic echo from a blood flow is detected to measure a blood flow velocity. Means for forming a plurality of ultrasonic acoustic lines, means for independently and simultaneously controlling the frequency, direction and focus of each of the plurality of ultrasonic acoustic lines, and a plurality of parts in a living body. Means for simultaneously measuring the blood flow velocity at different reference frequencies.

Further, the present invention provides an ultrasonic Doppler for transmitting an ultrasonic wave from a group of ultrasonic probes into a living body, detecting a Doppler shift frequency generated in an ultrasonic echo from a blood flow, and measuring a blood flow velocity. In the diagnostic apparatus, a plurality of transmission trigger pulse signal generating means for simultaneously generating at least two types of transmission trigger pulse signals of different frequencies, and a plurality of transmission delay control means for independently controlling the delay of the plurality of transmission trigger pulse signals Transmitting means for superimposing and transmitting simultaneously high-voltage transmission signals corresponding to the plurality of transmission trigger pulse signals, receiving means for receiving ultrasonic echoes from a living body, and reception signals obtained from the receiving means At least two types of band-pass filters (BPFs) that perform frequency classification on the plurality of received signals separated by the plurality of BPFs. A plurality of reception delay control means for independently performing delay control, a plurality of phase detection means for phase-detecting a plurality of reception signals controlled by the plurality of reception delay control means at different reference frequencies, and a plurality of phase detection means. Blood flow velocity calculating means for simultaneously calculating a blood flow velocity from a plurality of detection signals obtained, forming a plurality of ultrasonic acoustic lines at the same time, and independently controlling a frequency band, a direction, and a focal position for each ultrasonic acoustic line. And simultaneously measuring blood flow velocities at a plurality of sites in a living body at different reference frequencies.

[0010] With such a configuration, the directions and focal points of a plurality of ultrasonic acoustic lines formed in mutually different frequency bands can be freely controlled, and a plurality of blood flow velocities can be simultaneously measured. . Therefore, it is possible to simultaneously measure blood flow velocities from a plurality of sites distributed two-dimensionally in a living body at a plurality of reference frequencies.

[0011] In the ultrasonic Doppler diagnostic apparatus, further, color processing means for displaying waveforms of the blood flow velocities at the plurality of sites in different colors, and image synthesizing means for synthesizing each waveform within one display scale. May be provided to provide a composite image in which blood flow velocities at a plurality of sites are color-coded. With such a configuration, it is possible to display a waveform in which a plurality of blood flow velocities are synthesized in color, and both the efficiency of quantitative diagnosis and the efficiency of qualitative diagnosis visually grasped are improved.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to FIGS.

As shown in FIG. 1, an ultrasonic probe group 11
Transmits and receives ultrasonic waves to and from a living body. Hereinafter, transmission of ultrasonic waves will be described. Two transmission trigger pulse generators 31a and 32b having the same circuit configuration input the reference clock signal CK generated by the reference signal generator 21, and the transmission trigger pulse generators 31a and 32b are composed of frequency division counters and are different. outputs two kinds of transmission trigger pulse signal TRa and TRb frequency (f _R a and f _R b). This is shown in FIG. Here, an example is shown in which the division ratio of the transmission trigger pulse generator 31a is 2, the wave number of the pulse train is 4, the division ratio of the transmission trigger pulse generator 31b is 1, and the wave number of the pulse train is 8. The transmission delay control units 32a and 32b have a function of an electronic focus for controlling the direction and focus of the transmission ultrasonic acoustic line, and the transmission trigger pulse signals TRa and TRb respectively input as triggers for the transmission delay trigger pulse signal It outputs DTRa and DTRb, respectively.

Generally, the ultrasonic Doppler diagnostic apparatus transmits and receives a plurality of channels to and from the ultrasonic probe group at the same time.
For example, in the case of N-channel transmission / reception, the transmission delay trigger pulse signal DTRa is DTRa ₁ , DTRa ₂ ,.
Is composed of a group of signals N channels: TRa _N, is output while maintaining the delay time difference corresponding to the direction and focus of the pre-set transmission ultrasonic acoustic line. The same applies to the transmission delay trigger pulse signal DTRb.

The transmission delay trigger pulse signal DT shown in FIG.
Ra _m and DTRB _m are respectively show the m channels th signal representative. The transmission delay control units 32a and 32b respectively transmit a transmission delay trigger pulse signal DTR for N channels.
a and DTRb are output to the transmission circuit units 33a and 33b. The transmission circuit units 33a and 33b use the transmission delay trigger pulse signals DTRa and DTRb as triggers, respectively.
The high voltage transmission signals TXa ₁ , TXa ₂ ,.
..., TXa _N and TXb ₁ , TXb ₂ , ..., T
Xb _N is output.

In FIG. 2, one representative channel is TX.
Shown as a _m and TXb _m . Each high-voltage transmission signal is added by the adder 34 and TXa ₁ + TXb ₁ , TXa ₂
+ TXb ₂ ,..., TXa _N + TXb _N
Input to the V-MUX 41 (high voltage signal branch selector),
The HV-MUX 41 outputs transmission signals for N channels to desired channels of the ultrasound probe group 11.

In the high voltage transmission signal added to FIG.
Shows the channel eyes as TX _m. These N-channel high-voltage transmission signals are transmitted by transmission trigger pulse generators 31a and 31a.
A signal that includes two types of frequencies controlled by b and that has been subjected to two types of electronic focus control in accordance with the delay times controlled by the transmission delay controllers 32a and 32b is a combined signal. As a result, two types of ultrasonic transmission acoustic lines having different frequency bands, directions, and focal positions are formed from the ultrasonic probe group 11.

FIG. 3 is a schematic view showing an example of measurement of aortic valve regurgitation of the heart when an electronic sector type is used as the ultrasonic probe group. Two types of ultrasonic acoustic lines La and Lb are independently provided. It shows how it is formed.

Next, reception of an ultrasonic echo will be described.

FIG. 4 is a schematic view showing an example of a blood flow measurement at a stenosis lesion caused by a carotid plaque when a linear array type is used as an ultrasonic probe group.
4 shows band characteristics of ultrasonic echoes at a and Lb.
In FIG. 1, the ultrasonic echo is received by the ultrasonic probe group 11 and converted into an electric signal. The HV-MUX 41 selects a channel of the ultrasonic probe group and transmits a reception signal to the reception circuit unit 51 including an amplifier. Here, the receiving circuit unit 5
1 means that the reception signals Ea and Eb from the two ultrasonic acoustic lines La and Lb have been received at the same time.

The received signal amplified by the receiving circuit 51 is BP
Frequency separation is performed in F52a and 52b and distributed to the reception delay control units 52a and 53b. Reception delay control unit 53
In steps a and 53b, reception electronic focusing is performed on the ultrasonic acoustic lines La and Lb, and the directions of the acoustic lines are controlled. This means that the ultrasonic receiving acoustic lines are formed simultaneously and independently for the ultrasonic acoustic lines La and Lb.

Next, detection of the blood flow velocity will be described. The reference signals REFa and REFb for detection are supplied to the reference signal CK by a reference signal generator 61 composed of a frequency dividing counter.
Is divided and input to the phase detectors 54a and 54b. In the example of FIG. 2, the reference signal CK divided by 2 is RE.
Fa and 1 division indicate REFb. Here, the reference signal REFa and the transmission trigger pulse signal TRa frequency is the same at f _R a, the reference signal REFb and transmission trigger pulse signal TRb is also set to the same frequency f _R b.

FIG. 5 shows the frequency band and BP of the received signal.
4 shows the relationship between the passband characteristic of F and the reference signal. The frequency and phase detectors 54a and 54b convert the received signals separated into the ultrasonic acoustic lines La and Lb into the reception delay controllers 53a and 53b.
b, phase detection is performed with reference signals REFa and REFb for each of them, thereby detecting a phase shift (Doppler shift) signal corresponding to the speed of blood flow. The phase shift signals detected by the phase detectors 54a and 54b are converted into digital signals by the A / Ds 55a and 55b and input to the blood flow velocity calculator 71.

Referring to FIG. 5 in more detail, FIG.
FIG. 4 is an explanatory diagram for describing from reception of an ultrasonic echo to phase detection. According to the embodiment of the present invention, the frequency of reference wave signals REFa and REFb is f _R
a and f _R b. Received signal (electric signal) Ea
The frequency component having the (determined depending on the band characteristic of the ultrasonic wave) certain band around the f _R a distributed. Eb
Are also distributed around f _R b.

One of the characteristics of the present invention is that Ea and Eb are received at the same time, so that the received signal is Ea + Eb
It is one electric signal. This one electric signal Ea
+ Eb has a frequency band as shown in FIG. A BPF is used as a means for separating an electric signal having such a band into Ea and Eb. In other words, by providing a BPFa that allows only Ea to pass and a BPFb that allows only Eb to pass, one signal of Ea + Eb is converted to Ea and Eb.
b. Required characteristics as a pass band characteristic of the order BPF is as shown in FIG. 5, around the f _R a is as BPFa, it is necessary to have a bandwidth comparable to the bandwidth characteristics of Ea. The same applies to BPFb.

After separation into Ea and Eb, phase detection is performed, and phase detection is performed using reference wave signals having different frequencies. Perform phase detection with the reference wave signal REFa having only the frequency f _R a for Ea, performs phase detection with the reference wave signal REFb having only the frequency f _R b for Eb.

The blood flow velocity in the sample volume shown in FIGS. 3 and 4 is calculated by the blood flow velocity calculator 71 by FFT calculation. As a result, the measured blood flow velocity in the two samples volumes of ultrasonic acoustic line La and Lb independently with different reference frequencies f _R a and f _R b.

As described above, according to the embodiment of the present invention, the frequency band, direction, and focus of a plurality of ultrasonic acoustic lines are controlled simultaneously and independently, and a plurality of blood flow velocities are simultaneously controlled at different reference frequencies. It becomes possible to measure.
In the velocity distribution measurement of the aortic regurgitation shown in FIG. 3, the regurgitation speed becomes high in the case of regurgitation, but the ultrasonic acoustic line La
The backflow ejection site, an ultrasonic acoustic line Lb that is located near Kokorosaki unit, fast reverse flow is low reference frequency f _R a
Thus, the slow blood flow at the end of the backflow reaches the high reference frequency f
It becomes possible to measure simultaneously _R b.

FIG. 1 shows an example in which two types of ultrasonic acoustic lines are simultaneously formed. However, if the number of blocks is added to the parallel processing block in the figure, more ultrasonic acoustic lines can be simultaneously formed. Can be formed. Further, since the wave number of the transmission signal is not limited, the blood flow velocity can be measured by the continuous wave Doppler method in the embodiment of the present invention. Further, for each ultrasonic acoustic line, P
It is not necessary to use a common RF. For example, by operating the enable of the frequency division counters of the transmission trigger pulse generation units 31a and 31b, the PRF of the ultrasonic acoustic line La is multiplied by a constant with respect to that of the ultrasonic acoustic line Lb. Can also be set to

In FIG. 1, the two blood flow velocity data processed by the blood flow velocity calculation unit 71 are converted into waveforms by a DSC (Digital Scan Converter) 81 into an image display form adapted to a television raster, and are converted into a color processing unit. At 82, the color temperature is modulated. The two blood flow velocity waveforms subjected to the color processing are combined by the image combining unit 83 and displayed on the color monitor 91 as a blood flow velocity waveform. According to the embodiment of the present invention, the display method shown in FIGS. 6 and 7 is realized.

FIG. 6 shows an example in which blood flow velocities obtained from two types of ultrasonic acoustic lines are simultaneously and independently displayed at the carotid stenosis lesion shown in FIG. On the other hand, FIG. 7 shows an example in which blood flow velocities obtained in the same manner are superimposed and displayed. Here, the velocity waveform of the blood flow detected by the ultrasonic acoustic line La is displayed in white, and the velocity waveform of the blood flow detected by the ultrasonic acoustic line Lb is displayed in green. Speed is easily identified by color display.

According to the embodiment of the present invention, when a plurality of obtained blood flow velocities are synthesized and displayed, the blood flow velocities obtained from the respective ultrasonic acoustic lines can be identified by colors, so that the measurement results can be obtained. Make decisions easier. In the case of FIG. 4, there is an advantage that it is easy to qualitatively grasp the temporal correlation between the jet flow at the stenosis site and the turbulence at the rear of the stenosis.
In the case of FIG. 3, when measuring the orifice area of aortic stenosis, the sample volume of the ultrasonic acoustic line La is used for the stenosis of the aortic valve, and the sample volume of the ultrasonic acoustic line Lb is used for the left ventricle of the aortic valve. A valve port that is located on the outflow channel side and that is superimposed and displayed for both blood flow velocities at the same time to be quantitatively estimated later from a continuous formula (two points of blood flow are stored in a continuous flow path) There is an advantage that the area can be easily qualitatively determined during measurement.

[0033]

As described above, according to the present invention, the frequency, the direction, and the focus of a plurality of ultrasonic acoustic lines are simultaneously and independently controlled, and the blood flow velocities at a plurality of portions in the living body are changed to different reference In the case of measuring a plurality of blood flow velocities having different velocities in a living body, it is possible to simultaneously measure the blood flow velocities. In addition, since a waveform display in which a plurality of blood flow velocities are synthesized in color is performed, there is an effect that both the efficiency of quantitative diagnosis and the efficiency of qualitative diagnosis visually grasped are improved.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an ultrasonic Doppler diagnostic apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram showing signal waveforms at various parts in FIG. 1;

FIG. 3 is a schematic diagram showing an example in which a plurality of ultrasonic acoustic lines are simultaneously formed for a diagnosis of a heart.

FIG. 4 is a schematic diagram showing an example in which a plurality of ultrasonic acoustic lines are simultaneously formed for diagnosis of a carotid artery.

FIG. 5 is a diagram showing an example of a relationship between a frequency component of a received signal, a pass band characteristic of a band-pass filter (BPF), and a reference frequency of phase detection.

FIG. 6 is a schematic diagram showing an example in which a plurality of measured blood flow velocities are separated and displayed simultaneously.

FIG. 7 is a schematic diagram showing an example in which a plurality of measured blood flow velocities are superimposed and displayed simultaneously.

[Explanation of symbols]

 Reference Signs List 11 Ultrasonic probe group 21 Reference signal generator 31a, 31b Transmission trigger pulse generator 32a, 32b Transmission delay controller 33a, 33b Transmission circuit 34 Adder 41 HV-MUX 51 Receiver circuit 52a, 52b BPF 53a, 53b Reception delay control section 54a, 54b Phase detection section 55a, 55b A / D 61 Reference signal generation section 71 Blood flow velocity calculation section 81 DSC 82 Color processing section 83 Image synthesis section 91 Color monitor

Claims (3)

[Claims] An ultrasonic Doppler diagnostic apparatus for transmitting an ultrasonic wave from a group of ultrasonic probes into a living body, detecting a Doppler shift frequency generated in an ultrasonic echo from a blood flow, and measuring a blood flow velocity, Means for forming a plurality of ultrasonic acoustic lines, means for independently and simultaneously controlling the frequency, direction and focus of each of the plurality of ultrasonic acoustic lines, and different reference frequencies for blood flow velocities at a plurality of sites in a living body Ultrasonic Doppler diagnostic apparatus comprising: 2. An ultrasonic Doppler diagnostic apparatus which transmits an ultrasonic wave from a group of ultrasonic probes into a living body, detects a Doppler shift frequency generated in an ultrasonic echo from a blood flow, and measures a blood flow velocity, A plurality of transmission trigger pulse signal generation means for simultaneously generating at least two types of transmission trigger pulse signals of different frequencies; a plurality of transmission delay control means for independently performing delay control on the plurality of transmission trigger pulse signals; Transmitting means for superimposing and transmitting simultaneously high-voltage transmission signals according to the transmission trigger pulse signal, receiving means for receiving ultrasonic echoes from the inside of a living body, and frequency separation for a reception signal obtained from the receiving means. Performing at least two types of band-pass filters (BPFs) and independently delaying a plurality of received signals separated by the plurality of BPFs A plurality of reception delay control means for controlling; a plurality of phase detection means for performing phase detection on the plurality of reception signals controlled by the plurality of reception delay control means at different reference frequencies; and a plurality of phase detection means obtained by the phase detection means A blood flow velocity calculating means for simultaneously calculating a blood flow velocity from a detection signal, simultaneously forming a plurality of ultrasonic acoustic lines, and independently controlling a frequency band, a direction, and a focus position for each ultrasonic acoustic line, An ultrasonic Doppler diagnostic apparatus characterized by simultaneously measuring blood flow velocities at a plurality of sites in a living body at different reference frequencies. 3. The ultrasonic Doppler diagnostic apparatus according to claim 1, wherein color processing means for displaying waveforms of the blood flow velocities at the plurality of portions in individually different colors, and displaying each waveform in one display scale. An ultrasonic Doppler diagnostic apparatus comprising: an image synthesizing means for synthesizing the blood flow velocity;