JPH03277353A - Ultrasonic diagnostic device - Google Patents

Abstract

PURPOSE:To decrease the number of signal lines for connecting transducers from a thin tube to a device main body even in the case there are many transducers by selecting each receiving signal obtained from plural transducers arranged in the thin tube by a selecting means and sending it as a time series to a receiving means. CONSTITUTION:A pulser 14 generates a driving pulse, based on a rate pulse from a pulse generator 16, this driving pulse is sent to an electronic switch 12 through a signal cable 13, and by the switch 12, a prescribed transducer 11 is selected and driven. On the other hand, at the time of reception, in principle, the same transducer 11 is selected, and a receiving signal of the transducer selected by the switch 12 is outputted as a time series to a pre-amplifier 17 through the cable 13. According to this constitution, even in the case the number of transducer is large, the number of signal lines for connecting them to the device main body can be decreased to one piece or several pieces, wiring of the signal line in a thin tube is facilitated, and for instance, a guide wire can be allowed to pass through the thin tube.

Description

Detailed Description of the Invention [Purpose of the Invention (Industrial Field of Application) The present invention relates to an ultrasonic diagnostic apparatus that obtains tomographic images of a living body using ultrasonic waves. This invention relates to an ultrasonic diagnostic device that obtains high-resolution ultrasonic tomographic images of blood vessels and small digestive tracts.

(Prior art) Ultrasonic diagnostic methods emit ultrasound pulses into a living body and obtain biological information from reflected waves from each tissue. It has the advantage of being diagnostic. In the most widely used electronic scanning device, array-type piezoelectric transducers are used, and a predetermined delay time is applied to the drive signal or reception signal of each of these ultrasonic transducers. By giving , the ultrasonic beam is focused on a predetermined distance M (position) to improve azimuth resolution and obtain a tomographic image with excellent resolution.

Incidentally, in recent years, ultrasonic diagnostic technology has become capable of inserting transducers into the body, along with advances in higher frequency electronic circuits and microfabrication technology for transducers.

As a result, in gastrointestinal diagnosis, endoscopic approach or clinical practice is becoming widespread. More recently, attempts have been made to insert transducers even into blood vessels.

FIG. 5 is a schematic diagram showing a part of an ultrasonic diagnostic apparatus employing a method that has already been proposed. As shown in the figure, one ultrasonic transducer 1 is mounted inside the distal end of a catheter 30 having a diameter of 2 + om or less. A drive signal for driving the ultrasonic transducer 1 is sent to the transducer 1 from a transmitter/receiver 6 in the main body via a signal line and a ground line 3 embedded in the catheter tube wall 2.

This ff1f again! ', an acoustic mirror 4 is placed opposite the transducer 1.

This acoustic mirror 4 is attached to a rotation cable (so-called torque cable) 5, and this rotation cable 5 is further attached to a motor 7 provided on the main body side. As a result, the rotational motion by the motor 7 is transmitted to the acoustic mirror 4 via the rotational cable 5, resulting in high-speed rotational motion.

Further, the surface of the acoustic mirror 4 is inclined at about 45 degrees with respect to the rotation axis of the rotation cable 5. As a result, the ultrasonic waves emitted from the transducer 1 are reflected by the acoustic mirror 4 and are emitted at 90 degrees to the axis of rotation, that is, in a direction perpendicular to the wall 2 of the catheter. The reception operation is the same as the transmission operation, and the catheter wall 2
Only reflected ultrasound waves from a direction perpendicular to the direction are received.

On the other hand, in addition to the above method, a method has also been proposed in which the microtransducer 1 is directly rotated by a torque cable.

In any of these methods, this mechanical method is
The structure is relatively simple, and high frequency (20MH2~
(40 MHz is commonly used) is easy to implement, and has already reached the stage of clinical use.

(Problem to be solved by the invention) However, in the mechanical method shown in Fig. 5, although high-resolution images can be obtained using high-frequency ultrasound, a catheter is inserted into a curved blood flow like a coronary artery. In this case, the mechanical method is difficult to apply. That is, in the mechanical method, since the torque cable occupies most of the space in the center of the catheter, there is a problem that a guide wire necessary for the coronary artery cannot be attached.

Therefore, as another method to solve the drawbacks of such a mechanical method, there is a method using an array type transducer, which was already proposed in 1971.

However, this method has a problem in that the transducer and electronic circuitry are extremely complex.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an ultrasonic diagnostic apparatus using a mechanical method, which has a simple configuration, and is equipped with an ultrasonic probe to which a guide wire can be easily attached even within a coronary artery.

[Structure of the Invention] (Means for Solving the Problems) In order to solve the above problems and achieve the objects, the present invention takes the following measures. That is, the present invention provides an ultrasonic transducer that transmits and receives ultrasonic waves by arranging a plurality of transducers along the wall of a thin tube and driving these transducers with a transmitting means, and an ultrasonic transducer that is connected to each of the transducers and transmits these transducers in chronological order. a receiver (ci' means) for time-sequentially receiving the echo signals from the transducers selected by the selecting means; and a storage means for sequentially storing the received signals obtained by the receiving means; and addition means for synthesizing the time-series received signals from the storage means.

(Effects) By taking such measures, the following effects are achieved. By selecting each received signal obtained from a plurality of transducers arranged inside a thin tube using the selection means, it is possible to send them to the receiving means in time series, so even when there are many transducers, it is possible to The number of signal lines for connection from the main body to the main body of the device can be reduced to - or several. Therefore, wiring of the signal line inside the thin tube becomes easy, and the vicinity of the central axis of the thin tube can be made hollow, so that, for example, a guide wire can be passed through the thin tube.

(Embodiment) FIG. 1 is a schematic block diagram showing an embodiment of an ultrasonic diagnostic apparatus according to the present invention.

In FIG. 1, the ultrasonic diagnostic apparatus includes a pulse generator 16. balsa 14. Signal cable] 3. Electronic switch circuit 12. Array type ultrasonic transducer 11
-1 to 11-n.

In addition, a preamplifier 17 is used as a receiving system. A/D1g.

It has a RAM 19 (19-1 to 1.9-n) and an adder 20. Further, as a B-mode processing system, an envelope detection circuit 21 detects the envelope of the received signal to obtain a tomographic image. It has a logarithmic conversion table 22 for logarithmically amplifying this detected signal, and as a display system, it has an image memory 2B consisting of a frame memory and storing image data, and a TV monitor 24.

The array type ultrasonic transducers 11-1 to 11-
n is the tip of the catheter 30 which is a thin tube,
A plurality of transducers are arranged along the circumference of this catheter 30, and ultrasonic waves are transmitted and received from these transducers. Further, the electronic switch 12 as a selection means is also provided in the catheter 30 in proximity to the ultrasonic transducers 11-1 to 11-n. One end of the electronic switch 12 is
Each terminal is connected to the transducers 11-1 to 11-n, and the other terminals are commonly connected to the signal cable 13. Then, the electronic switch 12 selects a predetermined transducer from among these transducers 11-1 to 11-n in time series.

A pulse generator 16 built into the main body side generates a rate pulse, and outputs this rate pulse to a transmitting circuit 14 (hereinafter referred to as balsa 14). The balsa 14 generates drive pulses based on the rate pulses from the pulse generator 16. This drive pulse is sent via a signal cable 13 to an electronic switch 12 in the catheter,
A predetermined transducer is selected by this electronic switch 12, and one of the predetermined transducers is selectively driven.

On the other hand, during reception, in principle, the same transducer 11 is selected. The received signals of the transducers selected by the electronic switch 12 are output in time series to the preamplifier 17 provided on the main body side via the signal cable 13 inside the catheter 30.

That is, each transducer 11-1 to 11-n
A so-called aperture synthesis method is adopted in which the electronic switch 12 sequentially converts the signals from the electronic switch 12 into time-series signals and reconstructs the image when the signals from all the elements have been received.

In this way, the received signals from a plurality of transducers can be transmitted through one signal cable, so the number of signal lines in the catheter can be minimized.

The received signal via the electronic switch 12 passes through a preamplifier 17 and then is sent to an A/D 18 (analog
The signals are converted into digital signals by a digital signal converter) and stored in RAMs 19-1 to 19-rF (random access memories) in a time-series manner.

Here, a case where the number of signal lines in the catheter 30 is one will be explained as an example. The transmission signal output from one balsa 14 is sent to one transducer (for example, 11-1) selected by the electronic switch 12, and ultrasonic waves are emitted from this transducer 11-1 to, for example, a blood vessel.

On the other hand, the ultrasonic waves reflected within the blood vessel or from the blood vessel wall are received by the array type transducer 11-1, but the same transducer as used for transmission is selected by the electronic switch 12-1, and the ultrasonic wave reflected from the blood vessel wall is Only the received signal is sent to preamplifier 17.

In this way, ultrasonic waves are transmitted and received within a living body using a single transducer, so if 0 array-type transducers are used, one tomographic image is constructed by transmitting and receiving n ultrasound waves. be done.

Then, among the received signals obtained from each transducer, a plurality of signals are combined by an adder 20 serving as an adding means to obtain a resolution equivalent to that obtained when receiving signals with an equivalently large aperture.

That is, each received signal once stored in the RAMs 19-1 to 19-n is given a predetermined delay time by controlling the read timing.
They are combined by an adder 20. In this case, among the signals from the n transducers, the number of signals (effective aperture) for which the most effective reception beamforming is performed is determined.

For example, a received signal synthesis method when the number of signal lines is 5 will be described below. In FIG. 1, when an ultrasound image is constructed in a direction perpendicular to the surface of the m-th transducer, m-2° m-1, m, m+1. 5 of m+2
Addition processing is performed using the signals obtained from the two signals.

Then, the five signals stored in the memories 19-(m-2) to 19-(m+2) are added and synthesized by controlling the read timing by a control circuit (not shown). This results in five transducers m-2 to m+
2, the same performance as simultaneous reception can be obtained.

Next, to obtain an image in the m+1st direction, m
-1, m, m+1. m+2. The signals obtained by m+3 five transducers are combined. If n signals are obtained in advance in this way, they can be appropriately selected and combined in the receiving circuit to create a radial image (
PP1 image) can be easily obtained.

With this method, the signal acquisition time is almost the same as the conventional method of transmitting and receiving by driving several transducers simultaneously, and the time required for signal synthesis processing has also increased due to recent advances in digital signal processing technology. Almost real-time processing is becoming possible.

Next, a modification of the transducer driving method of the above embodiment will be described. That is, in the embodiment described above, one element transducer was used for one transmission and reception of ultrasonic waves, but the modified example is characterized in that a plurality of transducers are used. Here, for example, a case where three transducer elements are driven simultaneously will be explained. For the mth scan, the electronic switches 1.2- (m-1), 12-
m, 12-(m+1) are in the ON state.

That is, the transmission signal from the balsa 14 is transmitted to the transducer 11 via the signal cable 13 and the electronic switch 12.
-(m-1) to 11-(m+1) simultaneously.

Also, during reception, the transmission reducer 1.1-
The received signals from (m-1) to 11-(m+1) are output to a preamplifier 17 on the main body side via an electronic switch 12 and a signal cable 13.

According to such a modification, since the area of the transducer used for transmission increases, the transmission sensitivity can be increased, and the scanning pitch can be made finer as in the previous embodiment.

Next, FIG. 2 shows a second embodiment of the present invention. In this embodiment, the preamplifier 25 is connected to the electronic switch 1 inside the catheter 3o.
2 and the signal cable 13. That is, since the preamplifier 25 has a small output impedance, it is possible to sufficiently suppress signal deterioration in the signal cable 13.

Next, FIG. 3 shows a third embodiment of the present invention. In this embodiment, a plurality of signal cables 13-A are provided within the catheter 30.
, 13-B (but fewer than N trees), and correspondingly, 5 transmission/reception systems are provided.

Here, for example, a case where two signal cables are provided will be explained. In this case, balsa 14. consisting of two systems A and H. Transmission delay circuit 26. Signal line 13. Electronic switch 12. Preamplifier 17°A/D18. It has 19 RAM.

The balsa 14-A is connected to, for example, odd-numbered elements of the array transducer 11 via a signal cable 13-A and an electronic switch 12-A.

On the other hand, the balsa 14-B is connected to, for example, even-numbered elements of the array transducer via the signal cable 13-B and the electronic switch 12-B.

The same holds true during reception.

According to such a device, the transmission sensitivity can be increased, the transmitted ultrasonic beam can be focused, and even higher resolution can be achieved.

Furthermore, methods that combine the embodiments described above are also within the scope of the present invention. Further, the values of the number of vibrators, the number of simultaneously driven vibrators, etc. in the embodiments are not limited to the above-mentioned embodiments.

Furthermore, in the above-mentioned embodiment, it has been explained that an ultrasonic transducer is incorporated into the inside of the catheter 30, but this catheter does not need to be a strict catheter, and may be installed inside something like a thin tube. are all within the scope of the present invention.

Furthermore, the direction in which the transducers are arranged is not limited to the circumference of the thin tube as shown in the above-mentioned embodiments; for example, the transducers may be arranged in a direction parallel to the axial direction of the thin tube as shown in FIG. It's okay.

In this case, with respect to the cross section obtained in the case of Fig. 1,
A cross section along the right angle h" is obtained.

It goes without saying that various other modifications can be made without departing from the gist of the present invention.

[Effects of the Invention] According to the present invention, each reception signal obtained from a plurality of transducers arranged inside a thin tube can be selected by the selection means and sent to the reception means in time series. Even if there are many transducers, the number of signal lines for connecting the thin tube to the main body of the device can be reduced. Therefore, it is possible to provide a space in a thin tube for passing a guide wire, for example, so it is possible to realize an ultrasonic probe inside a thin tube with a guide wire attached.
For example, it is possible to observe the inside of a blood vessel with complex curves, such as a coronary artery. Furthermore, an ultrasonic diagnostic device that can pass optical fibers for thrombus removal treatment using a laser through thin tubes, and allows treatment to be performed while observing images inside blood vessels using an ultrasound probe, allowing safe and accurate treatment. can be provided.

[Brief explanation of the drawing]

FIG. 1 is a schematic block diagram showing an embodiment of an ultrasonic diagnostic apparatus according to the present invention, FIG. 2 is a schematic block diagram showing a second embodiment of the present invention, and FIG. FIG. 4 is a schematic block diagram showing a fourth embodiment in which the arrangement direction of the transducers is changed; FIG.
The figure is a schematic diagram showing a conventional mechanical scanning type catheter-based acoustic transducer. DESCRIPTION OF SYMBOLS 1... Ultrasonic transducer, 2... Catheter wall, 3... Signal line, 4... Acoustic mirror 5... Rotating cable, 6... Ultrasonic transmitter, 7... Motor,
11... Array small transducer, 12... Electronic switch, 13... Signal cable, 14... Balsa, 16... Pulse generator, 17.25... Preamplifier, 18... A/D , 19...RAM, 20...
Adder, 21... Envelope detection circuit, 22... Logarithmic conversion table, 23... Image memory, 24... TV monitor, 26... Delay circuit for transmission.

Claims (1)

[Claims] An ultrasonic transducer that transmits and receives ultrasonic waves by arranging a plurality of transducers along the wall of a thin tube and driving these transducers with a transmitting means; and a selection that is connected to each of the transducers and selects these transducers in chronological order. means for receiving echo signals from the transducer selected by the selecting means in time series; storage means for sequentially storing the received signals obtained by the receiving means; 1. An ultrasonic diagnostic apparatus comprising: an adding means for synthesizing received signals.