JPS63154167A - Ultrasonic diagnostic apparatus - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Objective of the Invention] (Industrial Field of Application) This invention relates to an ultrasonic diagnostic device that uses ultrasound to obtain information inside a living body, and in particular, it relates to an ultrasound diagnostic device that uses ultrasound to obtain information inside a living body, and in particular, to obtain blood flow information in addition to tomographic image information. The present invention relates to an ultrasonic diagnostic apparatus having a function of extracting.

(Prior Art) The ultrasonic Doppler method is known as a means for non-invasively extracting and measuring blood flow information in a living body, that is, blood flow velocity and blood flow volume. This is a method of extracting blood flow information from the Doppler frequency shift of ultrasound waves caused by blood flow in a living body. If blood flow measurement using this ultrasound Doppler method is used in conjunction with the display of real-time ultrasound tomographic images, and the blood flow measurement position, blood vessel course, intracardiac structure, etc. are observed and confirmed, more accurate blood flow measurement is possible. becomes.

The ultrasonic Doppler method includes a method using pulse waves and a method using continuous waves. The pulsed Doppler method can selectively detect only signals from the desired depth, so it has excellent distance resolution and is useful for knowing the extent and direction of abnormal blood flow, but it is difficult to measure when the blood flow rate is high. Ml becomes impossible.

On the other hand, the continuous wave Doppler method allows accurate measurement regardless of the magnitude of blood flow velocity, and is therefore particularly effective in diagnosing valve stenosis and valve insufficiency in the heart where blood flow velocity is high. When implementing this continuous wave Doppler method, it is necessary to perform both transmission and reception continuously, so separate ultrasound transducers are required for transmission and reception. Therefore, conventionally, literature; P, J, PRY: ULTRASOUND
(PARTI) p199. ELsEVIER(NEW
YORK) 197111, an ultrasonic transducer consisting of a circular vibrator was divided into two along the radial direction, one of which was used for transmission and the other used for reception.

However, with this method, the transmitted and received ultrasound beams spread out, so Doppler frequency deviations caused by movements other than blood flow, such as the movement of the heart wall, are also detected, allowing accurate detection of blood flow. It is difficult to extract only this information. In addition, although it is possible to extract blood flow information to a certain extent with this type of ultrasound transducer, it is difficult to obtain clear tomographic images. required.

(Problems to be solved by the invention) As described above, with the conventional technology, it is difficult to accurately measure blood flow using the continuous wave Doppler method. There was a problem in that it was difficult to obtain tomographic images.

An object of the present invention is to provide an ultrasonic diagnostic apparatus that can accurately extract blood flow information using the continuous wave Doppler method and that can also extract clear tomographic image information using the same ultrasonic transducer.

[Structure of the Invention] (Means for Solving the Problems) The present invention uses an annular array ultrasonic transducer in which a plurality of ring-shaped transducers are arranged concentrically as an ultrasonic transducer. During N extraction and blood flow information extraction using pulse waves, almost all of the ultrasonic transducer is used for transmission and reception, and when blood flow information is extracted using continuous waves, one part is used for transmission and the other part is used for reception. It is characterized by being selectively used as

(Function) - Tomographic image information can be obtained by performing high-speed scanning by emitting ultrasonic waves while mechanically rotating or pendulating the annular array ultrasonic transducer at high speed. If this annular array ultrasonic transducer is used, by electronically focusing the ultrasonic beam using the delay time given when driving each ring-shaped transducer, it is possible to Since ideal beam focusing is possible in any direction, clear tomographic image information can be obtained.

When measuring blood flow using the ultrasonic Doppler method, with one part of the annular array ultrasound transducer used for transmission and the other part used for reception, the ultrasound transducer is driven by continuous waves during transmission. Furthermore, since the same beam focusing performance as when extracting tomographic image information is obtained, it is less likely that Doppler frequency shifts due to movements other than blood flow, such as pulsation of the heart wall, will be detected. Become,
Only blood flow information is accurately extracted.

(Embodiment) Fig. 1 shows an ultrasonic diagnostic apparatus according to an embodiment of the present invention, and Fig. 2 (a) and (b) are plan views showing a portion of an annular array ultrasonic transducer. and a cross-sectional view.

As shown in detail in FIG. 2, the annular array ultrasonic transducer 1 includes one circular transducer 2a and several transducers arranged concentrically around the transducer 2a (in this example, 3) ring-shaped vibrators 2b to 2d. Specifically, a common electrode 4 serving as a ground electrode is placed on one side of a disk-shaped piezoelectric plate 3, and an individual electrode serving as a signal electrode divided into circular and ring shapes for each vibrator 28 to 2d is placed on the other side. The electrodes 5a to 5d are each formed by vapor deposition or the like. A ground lead wire 6 and signal lead wires 78 to 7d (see FIG. 1) are connected to the common electrode 4 and the individual electrodes 58 to 5d, respectively. Further, a backing material (supporting base), not shown, is attached to the individual electrode 5 side.

Here, all the transducers 2a to 2d of the annular array ultrasound transducer 1 are used when tomographic image information is extracted, but some of them, for example, the inner two transducers 2a and 2b, are used when blood flow information is extracted. The other part, that is, the two outer transducers 2c and 2d, is used for reception.

In FIG. 1, a pulse generator 8 and a continuous wave generator 9 are provided as driving sources for the ultrasonic transducer 1, and one of the two outputs is selected via a switch 10. The drive signal selected by the switch 10 is supplied to the transmitting/receiving units 12a to 12d.

The transmitting/receiving units 12a to 12d are provided corresponding to the respective vibrators 2a to 2d, and are each configured as shown in FIG. 3. That is, the drive signal is supplied to the corresponding vibrator via the transmission delay circuit 31 and driver 32, and the reflected wave signal from the vibrator is supplied to the preamplifier 33.
The signal is then extracted as a received signal via the reception delay circuit 34.

Switches lla to 11d are transmitting/receiving units 12a to 12
This is for turning on and off the drive signal d manually or the received signal output.

The received signal outputs of the transmitting/receiving units 12a to 12d are added by an adder 13, and then selectively supplied to a tomographic image display unit 15 and a Doppler unit 20 by a switch 14. The tomographic image display unit 15 is for extracting and displaying tomographic image information, and includes a logarithmic amplifier 16 and a detection circuit 1.
7, an image memory 18 and a CRT display 19.

The Doppler unit 20 is for extracting, displaying and/or recording blood flow information based on the Doppler frequency shift, and connects mixer circuits 21a, 21b and π/2 shift to the mouthparts 22 and a low-pass filter (L PF), A/D converters 24a and 24b that convert the in-phase and quadrature-phase outputs into digital signals, a fast Fourier transform circuit (FFT) 25, a memory 26, a CRT display 27, and It is composed of a recording device 28.

Next, the operation of this embodiment will be explained. The operation of this device consists of a tomographic image extraction and display mode and a blood flow information extraction and display/recording mode.

First, in the tomographic image extraction display mode, switch 10
is switched to the pulse generator 8 side, and switch ll is switched to the pulse generator 8 side.
By turning on c and 1.1d, the pulse generator 8
The outputs are input to transmitting/receiving units) 12a to 12d.

In the transmitting/receiving units 12a to 12d, the input pulse signal is delayed for a predetermined time by the transmitting delay circuit 31, and then
The signal is amplified by the driver 32 and supplied to the corresponding vibrators 2a to 2d. As a result, the annular array ultrasonic transducer 1 emits an electronically focused ultrasonic beam into the living body due to the delay action of the transmission delay circuit 31.

The ultrasound reflected waves from inside the living body are received by the ultrasound transducer 1 and converted into electrical signals to the transmitting/receiving unit 12a.
~12d will be done manually. Transmitting/receiving units 12a to 12d
The reflected wave signal input manually is amplified by a preamplifier 33, then delayed by a reception delay circuit 34 for the same time as the transmission delay circuit 31, and taken out as a reception signal. All the received signal outputs of the transmitting/receiving units 12a to 12d are added by an adder 13 (switches lla and llb are on).

The output of the adder 13 is input to the tomographic image display unit 15 via the switch 14, and is first subjected to logarithmic conversion in the logarithmic amplifier 16. The output of the logarithmic amplifier 16 is detected by a detection circuit 17 to become an image signal, which is input to an image memory 18. The image memory 18 stores the input image signals for one screen, and displays them as a tomographic image on the CRT display 19. In this case, the annular array ultrasonic transducer 1 is mechanically rotating or pendulating, and information such as the rotation angle is detected by a potentiometer (not shown), and part of the address information is stored in the image memory 18. Supplied as.

Since the annular array ultrasonic transducer 1 can obtain a good focusing effect in the scanning direction and the slice direction by electronic focusing of the ultrasonic beam by the delay circuits 31 and 34, for example, a near array ultrasonic transducer can be used. A clearer image can be obtained compared to the case where the

Next, in the blood flow information extraction display/recording mode, the switch 10 is switched to the continuous wave generator 9 side, and the switches lla to 11d are turned off, so that the output of the continuous wave generator 9 is transferred to the transmitting/receiving unit. 12a, 12b, and only the inner two transducers 2a, 2b of the annular array ultrasonic transducer 1 are driven by continuous waves. The reflected waves emitted from the transducers 2a and 2b into the living body and subjected to a Doppler frequency shift due to the flow, etc. However, since switches lla and llb are off, the two outer vibrators 2
Only the received signal outputs of the transmitting/receiving units 12C and 12C corresponding to signals c and 2d are added together by the adder 13. The output of the adder 13 is then supplied to the Doppler unit 20 by the switch 14, and first, the multipliers 21a and 21b are used to generate the output of the continuous wave generator 9 and a signal whose phase is shifted by the π/2 phase shifter 22. is multiplied by Multiplier 21a.

The output of 21b has high frequency components removed by low-pass filters 23a and 23b, and becomes an in-phase output and a quadrature-phase output. After these outputs are converted into digital signals by the A/D converters 24a and 24b, the fast Fourier transform circuit 25
The Doppler frequency shift due to blood flow, that is, the blood flow velocity or blood flow volume, is measured by Fourier transformation. These blood flow information are temporarily stored in the memory 26 and
It is displayed on the RT display 27 or recorded as a hard copy by the recording device 28.

Even in this blood flow information extraction display/recording mode, the use of the annular array ultrasound transducer 1 allows the ultrasound beam to be well focused. Therefore, it is possible to measure the FFU flow with high precision without being affected by Doppler frequency shift caused by the movement of moving parts such as the heart wall or the like near the blood flow to be measured.

The present invention can be implemented with various modifications without departing from the scope of the invention. For example, in the above embodiment, a plurality of transducers 2a constituting the annular array ultrasonic transducer 1 can be implemented.
Although only the individual electrodes 5a to 5d were divided for ~2d,
The piezoelectric plate 3 may also be divided for each vibrator, thereby reducing transmission/reception crosstalk such as mixing of a drive signal into a received signal.

In addition, in order to reduce transmission/reception crosstalk, as shown in FIG.
The piezoelectric plate 3 may be divided only between d and d.

Note that the piezoelectric plate 3 may be divided acoustically (therefore, it may be cut over the entire thickness direction,
It is also possible to simply add so-called notches (so-called half-cuts).

Furthermore, in the above explanation, the regions used for transmission and reception when extracting blood flow information are divided into transducer units, but as shown in FIG. It is also possible to divide the area into two along the radial direction, and use either one of the divided areas A and lb for transmission and the other for reception. Note that when extracting information on one tomographic image, both head regions 1A and 1b are electrically connected and used as one annular array ultrasonic transducer. When dividing the annular array ultrasonic transducer into two in this way, as shown in the figure, the piezoelectric plate 3
The electrodes (common a electrode 41 individual electrode 5a
~5d) only may be divided.

Further, in the above embodiments, the annular array ultrasonic transducer is shaped like a flat disk, but the ultrasonic wave transmitting and receiving surface may have a concave or convex shape, for example.

[Effects of the Invention] According to the present invention, almost all of the annular array ultrasound transducer is used when extracting tomographic image information, and when extracting blood flow information using the continuous wave Doppler method, one part is used for transmission and the other part is used for transmission. By using an annular array ultrasonic transducer for reception, the advantage of the annular array ultrasonic transducer that ideal beam focusing is possible in both the scanning direction and the slice direction perpendicular to the scanning direction can be utilized for valve operation, and a common ultrasonic transducer can be used. The user can easily obtain a clear tomographic image, and can also perform accurate blood flow measurement that is not affected by movement of parts other than blood flow.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an ultrasonic diagnostic apparatus according to an embodiment of the present invention, and FIGS. 2(a) and 2(b) are a plan view and a sectional view of an annular array ultrasonic transducer used in the same embodiment. , FIG. 3 is a block diagram showing the internal configuration of the transmitting/receiving unit in the same embodiment, FIG. 4 is a sectional view showing another example of the annular array ultrasonic transducer, and FIG. 5(a)
(b) is a plan view and a sectional view showing still another example of an annular array ultrasonic transducer. 1... Annular array ultrasonic transducer, 2
a to 2d... Vibrator, 3... Piezoelectric plate, 4... Common electrode, 5a to 5d... Individual electrode, 8... Pulse generator, 9... Continuous wave generator, 12a-12d... Transmission/reception unit, 15... Tomographic image display unit, 20.
...Dotsupura unit. Applicant's agent Patent attorney Takehiko Suzue Figure 2 Figure 4

Claims (3)

[Claims] (1) Transmit ultrasound into the living body using an ultrasound transducer, receive the reflected waves within the living body, and obtain in-vivo tomographic image information and the Doppler frequency polarization of the reflected waves due to the blood flow within the living body. In the ultrasonic diagnostic apparatus that extracts blood flow information based on blood flow, the ultrasonic transducer is an annular array ultrasonic transducer in which a plurality of ring-shaped transducers are arranged concentrically, and when extracting tomographic image information, the ultrasonic transducer is 1. An ultrasonic diagnostic apparatus characterized in that almost the entire portion of the ultrasonic wave is used for transmission and reception, and when blood flow information is extracted, one portion is selectively used for transmission and the other portion is selectively used for reception. (2) When blood flow information is extracted, some of the plurality of ring-shaped transducers constituting the ultrasonic transducer are used for transmission, and the other parts are used for reception. The ultrasonic diagnostic device according to item 1. (3) A patent claim characterized in that the ultrasonic transducer is divided into two along the radial direction, and when blood flow information is extracted, one of the two divided ultrasonic transducers is used for transmission and the other for reception. The ultrasonic diagnostic apparatus according to item 1.