JPS58138445A - 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 The present invention relates to an ultrasonic diagnostic apparatus, and in particular, has a plurality of arranged ultrasonic transducers, and transmits and receives an ultrasonic beam from the transducer surface toward a subject, and this transmission and reception is carried out by the transducer. The present invention relates to an ultrasonic diagnostic apparatus that is electronically scan-controlled so as to perform multiple consecutive scans that move approximately parallel to a plane.

In recent years, ultrasonic diagnostic devices that perform diagnosis using ultrasound have been widely used. This ultrasonic diagnostic device utilizes the fact that tissues and organs within the body have different acoustic characteristics.

In other words, when ultrasonic waves are emitted into the body for a very short period of time,
As ultrasound waves propagate through human tissues, some of them are reflected back from the boundaries of different tissues. Because it takes time for ultrasound to propagate within the body, waves reflected from places close to the ultrasound emission point are returned quickly, and waves reflected from places far away are delayed. The emission of ultrasonic pulses is repeated at regular intervals, but since ultrasonic waves have short wavelengths, they can be concentrated and emitted in one direction, and in this way, ultrasonic pulses are generated one after another as they propagate through the body. By detecting reflected echoes and displaying them on a cathode ray tube, it is possible to display the distribution of acoustic characteristics in body tissues. At this time, since healthy tissue and tumor tissue have different acoustic characteristics, it is possible to know the presence or absence of an abnormality within the tissue and its location from the pattern displayed on the cathode ray tube.

FIG. 1 shows a conventionally used electronic scanning type ultrasonic diagnostic device, in which a plurality of transducers 10 are arranged.
-1.10-2. ...10-n, and the camera element 1 of this transducer 12
Transmission and reception of the ultrasonic beam described above is performed from the zero plane. Transmission and reception of such ultrasonic beams is performed by each transducer 10-1.10-
2.・・Transducer/receiver 14- provided corresponding to 10-n
1, 14-2. ...14-n by electronic scanning control by the transmission trigger control circuit 16 or the ultrasonic signal control circuit 18. This electronic scanning control is illustrated in FIGS. 2 and 3.

That is, as shown in FIG. 2, appropriate excitation control with different delay amounts is performed on a plurality of vibrators selected from the 10 planes of vibrators, and the delay value at the center of the vibrator 10 being excited is increased. As a result, the sound wave curve of the sound wave transmitted from the transducer 10 is made concave, and as a result, a composite ultrasound beam that is focused at a predetermined focal position can be transmitted. Then, in synchronization with the transmission of the ultrasound beam, the transducer 10 is controlled to receive reflected echoes, which are input to the delay addition circuit 20. Here, the same amount of delay as for transmission is added to the reflected echo obtained via each transducer, and the received signal is calculated by adding these together.
The received signal thus obtained is outputted to a TV monitor or the like via the high frequency amplifier 22. Then, as shown in FIG. 3, this operation is performed multiple times in succession by shifting the transducer by -element, thereby transmitting and receiving multiple ultrasonic beams that move approximately parallel to the 10 planes of the transducer. With this, tomographic images are displayed on a cathode ray tube in almost real time.

Here, the number of arrayed transducers 10 is n, and the number of transducers controlled when transmitting and receiving ultrasonic beams is m.
Then, the number N of scanning lines of the ultrasonic beam moving almost parallel to the handler surface 10 is N=n-m+l...
... is expressed by the equation (1), and the image on the cathode ray tube is displayed based on the reflected waves of these N ultrasonic beams.

Therefore, in order to increase the resolution of the image displayed on the cathode ray tube, the number N of scanning lines of the ultrasonic beam should be increased. However, due to the acoustic characteristics of ultrasonic waves, there are limits to the number of arrayed transducers n per unit length and the number m of transducers to control transmission and reception.
There is a limit to the number N of scanning lines expressed by the first equation. For this reason, in conventional ultrasound diagnostic equipment, the density of the number of scanning lines N of the ultrasound beam is coarse, and as a result, the image displayed on the cathode ray tube is also coarse, as shown in FIG. 5 (5). The drawback was that sufficient resolution required for diagnosis could not be obtained.

In order to improve these drawbacks, conventional ultrasound diagnostic equipment takes advantage of the fact that the central axis of the ultrasound beam coincides with the central axis of the transducer that transmits and receives it, and increases the scanning line number density of the ultrasound beam by 2. A double version was used. That is, by dividing the controlled number of transducers 10 into an even number and an odd number, ultrasonic beams are created at every μ interval of the transducer arrangement interval, as shown in FIG. 4, and 2N ultrasonic beams are generated. was scanning. As a result, as shown in Fig. 5(B), it is possible to display an image on a cathode ray tube with twice the resolution compared to the conventional device described above. is limited to 2N. Therefore, if you want to display an image with higher resolution and image quality on a cathode ray tube, you can display the same received signal twice, or you can memorize the received signal and then connect adjacent lines. A method of displaying by adding weights and other means was adopted. but,
The former method has the drawback of displaying the same line on the cathode ray tube, resulting in a strong mosaic-like image quality. In addition, the latter method requires complicated calculation processing by a computer, and also requires extremely high calculation speed due to the need for real-time display. For this reason, the calculations actually performed are not sufficient, and the image displayed on the cathode ray tube, as shown in Figure 5 (C), emphasizes the outline of the target area, but the resolution deteriorates. However, there was a drawback that the image was blurred.

The present invention was made in view of such conventional problems,
The purpose of this is to simultaneously obtain two series of received information from the reception of the reflected wave for one ultrasound beam transmission, and to display a single image without weighting the received signal or displaying the same signal multiple times. It is an object of the present invention to provide an ultrasonic diagnostic apparatus which is capable of providing images with sufficiently high resolution and excellent image quality.

In order to achieve this object, the device of the present invention has a plurality of ultrasonic transducers arranged in an array, and transmits and receives ultrasound beams from the transducer surface toward the subject, and this transmission and reception is approximately parallel to the transducer surface. In an ultrasonic diagnostic device that is electronically controlled to perform multiple consecutive scanning scans, two sets of transducer groups in different combinations receive reflected echoes for one ultrasound beam transmission and reception. It is characterized in that two series of received signals are obtained for each transmission of an ultrasonic beam.

Next, preferred embodiments of the present invention will be described based on the drawings. In addition, the same number 41 is attached to the parts corresponding to the above-mentioned device,
The explanation will be omitted.

FIG. 6 shows a preferred embodiment of the ultrasonic diagnostic apparatus of the present invention, which includes a transducer 12 having a plurality of transducers 10 arranged in the same manner as the conventional arrangement, and a transducer 12 having a plurality of transducers 10 for transmitting and receiving. 14, and a transmission trigger control circuit 16 and an ultrasonic signal control circuit 18 that control the transceiver 14.

Then, in the same way as normal electronic scanning, an ultrasonic beam as shown in FIG. Get a book ultrasound beam. In this embodiment, in performing the above scanning, the following control is performed in order to scan with 2N ultrasonic beams. That is, by utilizing the fact that the central axis of the ultrasonic beam coincides with the central axis of the arrayed transducers 10 to be excited and controlled, even and odd numbers are selected from the 10 groups of transducers of the transducer 12, as shown in FIG. The transducer 1 of the transducer 12 is designed to alternately select two transducers and control their excitation.
2N ultrasonic beams are obtained that move approximately parallel to the 0 plane and at intervals equal to the arrangement interval of each transducer. Figure 8 shows the ultrasonic beam transmitted in this way.The solid line shows the ultrasonic beam transmitted by controlling the excitation of even number of transducers, and the broken line shows the ultrasonic beam transmitted by controlling the excitation of odd number of transducers. There is. In the embodiment, the total number of oscillators IO is n=64, and an even number of oscillators are subjected to excitation control. Shake. Number of children. = 8, and the number of scanning lines 2N of the ultrasonic beam is calculated from the above equation (1) as 2N = 2.
(64-8+1) = 114 2N = 114 〇The feature of the present invention is that the reception of reflected echoes for one transmission of an ultrasound beam is performed by two sets of 10 groups of transducers in different combinations. Since two series of received signals are simultaneously formed by transmitting an ultrasound beam, it is possible to perform calculations such as weighting on the received signals and display them, or to display the same signal twice. For example, images with high resolution and high quality can be displayed on a cathode ray tube without the need for
In the embodiment, u, 2N ultrasonic beams are scanned, but according to the present invention, two series of received signals are obtained for one ultrasonic beam, so it is the same as doubling the scanning line density. As a result, it is possible to display an image on a cathode ray tube with the same resolution and quality as an image displayed based on scanning of 4N ultrasonic beams.

In this way, two ultrasound beams are transmitted simultaneously for one ultrasound beam transmission.
In order to obtain a series of received signals, the apparatus of this embodiment is provided with two series of receiving circuits 30 and 32.

Then, the transmitter/receiver 14 is controlled in synchronization with the transmission of the ultrasonic beam, and the plurality of transducers 10 selected to receive the reflected waves of the ultrasonic beam are set to a receiving state. In the example, when eight transducers are used to transmit an ultrasonic beam, the eight transducers are set as they are for reception, and when seven transducers are used to transmit an ultrasonic beam. , these seven transducers and one other transducer adjacent thereto, a total of eight transducers, are set for reception. The reflected echoes received by the eight transducers 10 set in the receiving state in this manner are input to two series of receiving circuits 30 and 32 via the ultrasonic signal control circuit 18, respectively, and are processed as follows. Thus, two series of received signals are obtained.

First, one receiving circuit 30 uses the eight input reflected echoes as they are to obtain one series of received signals. this. Therefore, a delay adder circuit 40-1 is provided in which the phase amount of each reflected echo is calculated in advance using eight transducers.
Delay addition is applied to the two reflected echoes based on the above phase i.
The series of received signals are calculated and outputted via the frequency amplification circuit 42-1.

The other receiving circuit 32 selects seven reflected echoes from the input reflected echoes by a switching circuit 44, and selects seven reflected echoes from the input reflected echoes.
Based on one reflected echo, the other series of received signals is obtained. For this reason, a delay adder circuit = 10-2 is provided in which the phase amount of each reflected echo is calculated in advance using seven transducers, and the seven reflected echoes inputted via the switching circuit 44 are calculated based on the above phase amount. The received signal of the other series is calculated by performing delay addition and is outputted via the frequency amplification circuit 42-2.

The calculations of the two series of received signals in each of the receiving circuits 30 and 32 as described above are performed simultaneously.

In the embodiment, as described above, the transmission of ultrasonic beams by the eight transducers 1' and the transmission of the ultrasonic beams by the seven transducers 1r are repeatedly performed. Therefore, when ultrasonic beams are first transmitted by eight transducers T, the delay adder circuit 4o-1 receives the eight transducers shown in FIG. 9(a).
The reflected echoes are inputted through the seven transducers R, and the reflected echoes are inputted into the other delay adder circuit 4o-2 via the seven transducers R shown in FIG. 9(b). These delay adder circuits 40-1 and 40-2 calculate received signals a and b shown as AODD * BODD in FIG.
-2 respectively. Next, when ultrasonic beams are transmitted by the seven transducers T, reflected echoes are input to the delay addition circuit 4o-1 via the eight transducers R shown in FIG. 9(d). The other delay circuit 40-2 includes FIG.
) Reflected echoes are input via seven transducers R shown in FIG. These delay adder circuits 40-1 and 40-2 are configured based on the reflected echoes inputted to each of the delay adder circuits 40-1 and 40-2.
The received signals d and c shown in ooo l coon are calculated and input to the memory circuits 48-1 and 48-2, respectively.

Each of these memory circuits 46-1.46-2.48-1.48
-2 is the T of the ultrasonic reception signal by the known line memory.
Using the V scan line conversion method, each input and stored received signal I
ll l) l J c is time-compressed at a compression rate of 4, the display signal selection circuit 50 is operated, the signal is output to the TV monitor, and the 10th
As shown in l'JODD in the figure, the odd field ■,
The received signals a and b are displayed in ■, and the odd field ■.

(6) Display signals c and d on receiver 1. Note that the memory circuit =
The input of the received signals d and c to the storage circuit 46-1.48-2 is performed by the storage circuit 46-1.46-2 in the fields ■, ■, ■, ■.
Bamboo is destroyed while displaying a signal. By repeating this operation, the life number field M=4n+1゜M=
4n+2 (n=o, 1.2-), B in Figure 10
The received signals shown in ODD are sequentially displayed. When the display of the received signal in the odd field is completed, the same display method is used to perform no-in pv-scanning by pulse control of the standard TV synchronization signal.
M of even field of signal = 4n+3°8I =
4n+4 (li='Q, L21-), the received signals shown at EIIVIN in FIG. 10 are sequentially displayed. In this way, the image of the scanning line 1f4N is displayed on the cathode ray tube, as shown in FIG. 8 (13).

This research consists of the above structure, and its operation will be explained next.

First, the vibrator 10-1. When ~10-8 is excited and controlled and an ultrasonic beam is transmitted, the reflected echo is transmitted to the transducer 10-8.
1 to 10-8 to each receiving circuit 30.32. The delay addition circuit 40-1 of the receiving circuit 30 calculates one series of received signals a shown in AODD in FIG. 10 from the reflected echoes inputted via the transducers 10-1 to 10-8, and At the same time, the delay addition circuit 40-2 of the other receiving circuit 32 is stored in the storage circuit 46-1.
is B in FIG. 10 from reflected echoes input via the transducers 10-2 to 10-8. The other received signal indicated by DD is calculated and stored in the storage circuit 46-2.

Then, the storage circuits 46-1 and 46-2 use the TV scanning line system for ultrasonic reception signals using a known line memory to store received signals a and b as shown in BODD in FIG. 1θ.
is compressed in time with a compression ratio of 4 and displayed in the odd fields ■ and ■. 10-2
~10-9 to each receiving circuit 30, 32. The delay addition circuit 4o-1 of the % receiving circuit 30 receives the reflected echoes input via the transducers 10-2 to 10-9 as shown in FIG. 10. Calculate the received signal d shown in DD,
This is stored in the storage circuit 48-1. At the same time,
The delay addition circuit 40-2 of the receiving circuit 32 includes a switching circuit 4.
4, reflected echoes are inputted via the transducers 10-2 to 10-8, and the delay addition circuit 40-2 calculates a received signal C shown at Cooo in FIG. The data is stored in the memory circuit 48-2.

These d-pin memory circuits 48-1 and 48-2 use the same i'V scanning line system as described above, as shown in E of FIG.

The received signal time-compressed at a compression rate of 4 is displayed in the odd fields (■) and (2) so as not to be displayed on the DD.

Repeat the above operation until M = 4 for the odd field.
The received signal shown at Eoon in FIG. 10 is displayed in the first order at n+1 and M=4n+2 (n=0.1.2-).

After the received signal has been displayed on the odd field, the even field M =
4n+3. M=4n+4. , (n = sail 1, 2
．．・) The received signals shown in EBnp+ in FIG. 10 are sequentially displayed.

As a result, an image as shown in FIG. 8) is displayed on the cathode ray tube in real time.

Note that the present invention is applicable to an ultrasonic TV scan converter such as a digital scan converter or an X
It can also be applied to Y monitors. FIG. 11 shows an ultrasonic diagnostic apparatus used in such cases. In this device, the received signal calculated by the delay adder circuit 40-1 is directly input to the display signal selection circuit 50 via the high frequency amplifier circuit 42-1, and the received signal calculated by the delay adder circuit 40-2''T
: The received signal to be calculated is inputted to the storage circuit 46 via the high frequency amplification circuit 42-2, where it is subjected to a predetermined delay and inputted to the display signal selection circuit 50. Therefore, the received signal shown in FIG. 12 will be displayed on the frame.

) However, if this continues, the number of frames will be reduced by half. Therefore, when the apparatus of the present invention is used for such purposes, it is sufficient to use the circuit shown in FIG. 6 and display the image on a frame with the compression ratio doubled as shown in FIG. 13.

Further, the present invention can be used not only in a linear scan type ultrasonic diagnostic apparatus but also in other types of ultrasonic diagnostic apparatuses, such as sector scan type ultrasonic diagnostic apparatuses.

As described above, according to the present invention, two sets of transducers in different combinations receive reflected echoes for one transmission of an ultrasound beam, and two sets of transducers are received at the same time by one transmission of an ultrasound beam.
By obtaining a series of received signals, an image with high resolution and high quality can be displayed without weighting the received signals or displaying the same received signal multiple times.

[Brief explanation of the drawing]

Figure 1 is a block diagram of a conventional ultrasound diagnostic device, Figure 2 is an explanatory diagram of the operation of a group of transducers that transmit ultrasound beams, and Figure 3 is an ultrasound beam that is continuously scanned multiple times along the transducer surface. Fig. 4 is an explanatory diagram of excitation control of the transducer when scanning the ultrasonic beam at every bar interval of the transducer arrangement interval, and Fig. 5 is an explanatory diagram of the excitation control of the transducer when scanning the transducer at every bar interval of the transducer arrangement interval. 6 is a block diagram showing a preferred embodiment of the ultrasonic diagnostic apparatus according to the present invention; FIG. 7 is an explanatory diagram of excitation control for the transducer;
Fig. 8 is an explanatory diagram of the scanning density of the ultrasonic beam and the image displayed on the cathode ray tube, and Fig. 9 shows the relationship between the transducer that transmits the ultrasonic beam and the transducer that receives the reflected echo. 10 is an explanatory diagram for converting a received signal into a 'vV display line with a compression rate of 4. FIG. 11 is a block diagram showing another embodiment of the apparatus of the present invention, and FIG. An explanatory diagram of the case where the received signal of the device shown in the figure is converted into a TV display line, etc., and Fig. 13 is an explanatory diagram of the case where the received signal is converted into a TV display line, etc. with a compression ratio of 2. Child. Applicant: Aloka Co., Ltd. Figure 4 (A) (B) T&R (θ cunning transmission/reception control) T&R (7 & transmission/reception h control) (C) Figure 8 (A) Off diagram section Excitation ALL < 1zFt ( ChiL Naiha [first born (B) 9 years old R: receiving dynamic child

Claims (1)

[Claims] A plurality of ultrasonic transducers are arranged in i11, and an ultrasonic beam is transmitted and received from the transducer surface toward the subject, and this transmission and reception is performed several times in a direction substantially parallel to the transducer surface. In ultrasonic diagnostic equipment that is electronically controlled to perform continuous scanning, two sets of transducers in different combinations receive reflected echoes for one ultrasound beam transmission. An ultrasonic diagnostic apparatus characterized in that two series of received signals are obtained for each transmission. (2. The ultrasonic device according to claim (1), characterized in that two sets of even-numbered transducers and odd-numbered transducer groups receive reflected echoes for one ultrasound beam transmission. Diagnostic equipment.