JPH032536B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an endoscopic ultrasonic diagnostic apparatus, and more particularly to an improved endoscopic ultrasonic diagnostic apparatus capable of diagnosing a wide range of diagnostic sites using an electronic scanning probe.

2. Description of the Related Art Ultrasonic diagnostic apparatuses that emit an ultrasonic beam into a subject and display an image of a desired diagnostic site within the subject based on echoes reflected from the subject are well known. In normal ultrasound diagnostic equipment, a probe that transmits and receives ultrasound beams is placed in close contact with the body surface, and the ultrasound beams are transmitted and received from the body surface.
It has not been possible to observe and display clear images of organs and other organs located deep within the subject, and in recent years, ultrasound beams have been developed by inserting a probe into the body cavity of the subject and directing ultrasound beams from within the body cavity to the organs deep within the subject. A device that transmits and receives waves has been proposed.

FIG. 1 shows a conventional example of the endoscopic ultrasonic diagnostic apparatus described above, in which an endoscopic shaft 40 is inserted into a body cavity 10a of a subject 10, such as the esophagus, stomach, rectum, vagina, urethra, etc. It consists of a configuration in which an ultrasound beam 200 is transmitted and received from a probe 12 fixed at the tip of a visual axis 40 to a desired diagnosis site. In a conventional general endoscopic ultrasonic diagnostic device, the probe is provided with a single vibrating element, and the position of the probe 12 is moved while transmitting and receiving one ultrasonic beam 200. and rotated to observe a desired ultrasound tomographic image. However, with this conventional device, it takes a long time to obtain a single tomographic image, and it is said that it is not possible to obtain accurate images of moving organs, such as those that move due to breathing or heartbeat. There was a problem. Therefore, in recent years, an apparatus has been proposed that uses an electronic scanning probe as the probe 12 and covers a comparatively wide range of diagnostic sites in real time by electronic high-speed scanning.

FIG. 2 shows this type of electronic scanning probe 12, in which a plurality of vibrating elements 16-
1 to 16-n are arranged at equal intervals along the radiation surface 12a, and the vibration elements selected from the vibration element group 16 are excited and driven at each wave transmission/reception timing. An apparatus for obtaining endoscopic ultrasound tomographic images in a timely manner has been proposed.

The conventional apparatus shown in FIG. 2 has the advantage of being able to easily observe the diagnostic site in real time, but the diagnostic area is limited by the array length of the vibrating element group 16, and the necessary diagnostic The drawback was that it was not possible to observe all parts at once. and,
In the conventional device shown in FIG. 2, the arrangement length of the vibrating element group 16 must be increased in order to expand the diagnostic area, making it difficult to insert such a probe 12 into a body cavity. There was a drawback.

The present invention was made in view of the above-mentioned conventional problems, and its purpose is to provide an improved endoscopic ultrasound diagnostic device that can reduce the size of the probe and cover a wide range of diagnostic sites. There is a particular thing.

In order to achieve the above object, the present invention provides a probe having a plurality of vibrating elements fixed to the tip of an endoscopic shaft inserted into a body cavity of a subject and arranged in a convex shape at equal intervals; means for exciting and driving a vibrating element selected from the group according to a predetermined program at each wave transmission/reception timing, the excitation driving means driving the vibrating element group into a plurality of arbitrary combinations having two or more vibrating elements. It is characterized by having a wave transmission/reception control circuit which divides the beam into two groups and performs a plurality of ultrasonic beam transmission/reception operations having different ultrasonic beam directivity characteristics for each group.

Preferred embodiments of the present invention will be described below based on the drawings.

A preferred embodiment of the invention is shown in FIG.
Probe 1 fixed to the tip of the endoscopic axis 40 in FIG.
2 has a plurality of vibration elements 16-1 to 16-n arranged in a convex shape at equal intervals, and has a radiation surface 12a.
The ultrasonic beam 200 emitted from the probe 12 has a radiation angle of 100, and by arbitrarily setting the viewing angle determined by this radiation angle 100,
It is possible to display an endoscopic image with a wide diagnostic field of view without increasing the length of the probe, and as a result, a wide range of diagnostic sites can be covered with the small probe 12, and it is possible to enter the body cavity 10a. It is possible to shorten the diagnosis time without causing pain to the subject during insertion.

FIG. 4 shows a more specific configuration of the probe 12 according to the present invention, in which the vibrating element group 16 is arranged on the convex vibrator fixing surface of the substrate 42, and A plurality of lead wires 44 arranged on the planar side surface of the substrate 42 are connected to each other, and each vibrating element 16 is connected to an external excitation drive via the lead wires 44 by a terminal 46 provided on the back surface of the substrate 42. connected to the circuit.

FIG. 5 shows the internal structure of the probe according to the present invention and its vibrating element driving means. Inside the probe, a plurality of vibration elements 16-1 to 16-n are arranged in a convex shape at equal intervals along the radiation surface 12a. In FIG. 5, each vibration element 16 is
It consists of an electroacoustic transducer such as PZT, and has a nearly rectangular vibration surface.

Analog switches 18-1 to 18-n are connected to each vibrating element 16, and the vibrating element selected by the predetermined analog switch is connected to the transmitter 2.
0 and receiver 22. The reflected echo signal detected by the receiver 22 is displayed on a display 2 consisting of a CRT or the like.
4 and displayed on a display 24 whose sweep is controlled by a synchronizing signal from a transmitter 20. From the vibrating element group 16, an arbitrarily selected number and combination of vibrating elements are excited and driven at each wave transmitting/receiving timing of the wave transmitter 20 by an analog switch group 18 whose opening and closing are controlled according to a predetermined program.
In the illustrated embodiment, four adjacent vibrating element groups 16 from the left end are excited and driven at each wave transmission/reception timing, and the selected combination of vibrating element groups is sequentially moved to the right one by one. That is, the first wave transmission and reception is performed by the vibrating element groups 16-1 to 16-n, and the second wave transmission and reception is performed by the vibrating element groups 16-2 to 16-5. Therefore, by supplying a common excitation signal from the transmitter 20 to each selected vibrating element without requiring any delay control, the probe emits a signal in the normal direction of its radiation surface 12a. An ultrasound beam 200 is emitted, which can perform sector scanning with a radiation angle of 100 centered on a point 50, which is the center of the convex surface of the probe.

As described above, according to this embodiment, the probe 12
The ultrasonic beam 200 can be radiated from the body cavity 10a of the subject 10 at a desired radiation angle 100 from the radiation surface 12a, making it possible to display endoscopic images with a wide diagnostic field of view. Furthermore, according to this embodiment, a common excitation signal without delay control is supplied to each vibrating element 16, and no second main pole is generated.
It is possible to obtain high-resolution images by increasing the vibration frequency, and there is no need for conventional delay control for sector scanning of a group of vibrating elements arranged in a straight line. It becomes possible to significantly simplify the electronic circuit. That is, according to the device of the present invention, the vibration elements 16-1 to
Since the 16-n itself is arranged in a convex shape at equal intervals, there is no need to provide different delay times for each vibrating element as in conventional electronic sector scanning, and it is possible to scan sectors with a wide viewing angle using a simple control circuit. It becomes possible to obtain a sound wave beam 200.

However, in this arc-shaped probe, each ultrasonic beam is directed in the normal direction of the arc, so the beam spacing is relatively wide, and especially at the tip of the sector-scanning ultrasonic beam, the beam spacing increases significantly. , a problem arises in that the resolution in this part decreases.

In order to solve this problem, in the present invention, a new ultrasonic beam transmission and reception method is proposed,
A preferred embodiment thereof will be described below with reference to FIGS. 6 to 8.

FIG. 6 shows a probe having a plurality of vibrating elements 16 arranged in a convex shape suitable for the present invention and its ultrasonic beam, and FIG. 7 shows the probe of FIG. An embodiment of a wave transmitting/receiving control circuit for performing ultrasonic beam transmitting/receiving functions according to the invention is shown.

As is clear from Figure 6, the probe is made of PZT.
Approximately rectangular vibration elements 16-1 to 16-n made of electroacoustic transducer elements such as the above are arranged in a convex shape at equal intervals. The ultrasonic beam transmitting and receiving functions of the probe are controlled by the transmitting and receiving control circuit shown in FIG.
A transmission signal is supplied from 26-n. Transmission circuit 2
Delay trigger circuits 28-1 to 28-n are connected to 6-1 to 26-n, respectively, and each delay trigger circuit 28-1 to 28-n has its own delay time set and controlled by a control circuit 30. There is.
The transmission system of the wave transmission/reception control circuit has the above configuration, and a transmission signal with a predetermined delay time is supplied to a desired vibrating element 16 selected by the control circuit 30.

On the other hand, in order to receive the reflected echo received by the vibration element 16, each vibration element 16-1
-16-n have reception switching circuits 32-1 to 32-n.
are connected to each reception switching circuit 32-1 to 32-n.
The receiving function is controlled by a control signal from the control circuit 30. Each reception switching circuit 32-1 to 32-n has a delay circuit 34-1 to 34-n.
4-n is connected, and each delay circuit 34-1 to 34-3 is further connected to
The output of 4-n is supplied as a received signal to a display section (not shown) via a receiving circuit 36.

By the wave transmission/reception control circuit shown in FIG. 7, the vibrating elements 16 are divided into a plurality of groups of arbitrary combinations each having two or more vibrating elements, and in the illustrated embodiment,
Each vibration element 16 is divided into four elements. Then, a plurality of ultrasound beam transmission/reception operations having different ultrasound beam directivity characteristics are performed on each set of transducer elements from the transmission/reception control circuit at each ultrasound beam transmission/reception timing.

Referring to the ultrasound beam in Figure 6 below,
The wave transmitting/receiving function according to the present invention will be explained in detail.

In the illustrated embodiment, each set of four vibrating elements 16 is subjected to five ultrasound beam transmission and reception operations. Among the ultrasonic beams indicated by solid lines in FIG. The ultrasonic beam is obtained by supplying a common transmission signal with no mutual delay time to the four vibrating elements 16 forming each set. The first basic ultrasonic beam 400-1 is a vibration element group 16-1 to 16
−4 is obtained when the same transmission signal is supplied to
Similarly, the basic ultrasonic beam 400-2 is transmitted through the vibration element 1.
This is obtained when the same transmission signal is supplied to 6-2 to 16-5.

This embodiment is characterized in that at least one auxiliary ultrasound beam is emitted for each basic ultrasound beam.

In the illustrated embodiment, for each elementary ultrasound beam 400 four auxiliary ultrasound beams 500,
600, 700 and 800 are emitted. Basic ultrasound beam 400 and each auxiliary ultrasound beam 50
0, 600, 700 and 800 each have different ultrasonic beam directivity characteristics, and the delay trigger circuit 28 transmits signals to the four vibrating elements selected at each wave transmission/reception timing by the control circuit 30 in FIG. By giving different delay times,
Auxiliary ultrasound beams having different ultrasound beam directivity characteristics as described above can be obtained. For example, the auxiliary ultrasound beam 500-1, which is clockwise with respect to the basic ultrasound beam 400-1, has the vibration element 16-
1 to 16-4, elements 16-4, 16-3, 16-
The auxiliary ultrasonic beam 600-1 is obtained when transmission signals having delay times increasing in the order of 2 and 16-1 are supplied, and the auxiliary ultrasound beam 600-1 is formed by supplying transmission signals having a small delay time difference. On the other hand, the auxiliary ultrasonic beam 800-1 located counterclockwise from the basic ultrasonic beam 400-1 is connected to the vibration elements 16-1 to 16.
-4 elements 16-1, 16-2, 16-3, 16
−4, and the auxiliary ultrasonic beam 700
-1 can be obtained by reducing this delay time difference.

As described above, by forming four auxiliary ultrasonic beams 500, 600, 700, and 800 for each basic ultrasonic beam 400, as shown by the broken line in FIG. Ultrasonic beams with uniform spacing can be emitted uniformly to obtain reflected echoes with extremely high resolution. This reflected echo is supplied from a reception switching circuit 32 selected by a control circuit 30 to a reception circuit 36 through a delay circuit 34, and a reception signal is supplied to a display section (not shown). The delay time by the delay circuit 34 described above is set to be the same as the corresponding delay time during transmission, and the reception characteristics can be set in the direction of the ultrasonic beam shown in FIG. 6.

As described above, the first set, that is, the transducer elements 16-1 to 16-4, is transmitted and received five times with different ultrasonic beam directivity characteristics, and the ultrasonic beam 50
0-1,600-1,400-1,700-1,
After scanning the five ultrasonic beams indicated by 800-1, the control circuit 30 selects the second set of transducer elements 16-2 to 16-5, and sequentially performs different orientations similar to the first set. Characteristic ultrasonic beam transmission and reception functions are performed.

In the above manner, as is clear from Fig. 6, it is possible to transmit and receive ultrasonic beams at five times the density of the basic ultrasonic beam, and to obtain images with extremely high resolution. Become.

Although the receiving circuit 36 and the display unit connected thereto in FIG. 7 are not shown in detail, they are well-known.
It can be formed by a display made of CRT or the like. By making the sweeping action of the display section the same as the ultrasonic beam radiation characteristics shown in FIG. 6, an accurate image can be formed in real time.
In order to form the ultrasonic beam trajectory on the display section as shown in the figure, a complicated sweep control action is required, and in order to simplify the display section, a virtual ultrasonic beam sweep as shown in Fig. 8 is used. It is preferable to display the information.

FIG. 8 shows the auxiliary ultrasonic beams 500, 6 of FIG.
00, 700, and 800, the ultrasonic beam reception signals are processed assuming that the respective beam extension lines coincide with the arcuate center 0 of the probe. According to the processing characteristics shown in FIG. 8, although there is a slight difference between the actual biological tissue and the image, the control circuit can be significantly simplified, and it is suitable for obtaining an ultrasonic diagnostic device with a simple configuration. be.

In the illustrated embodiment, the ultrasonic beam transmission and reception is performed five times for each set of selected transducer elements, but the number of transmission and reception can be set arbitrarily to achieve the desired resolution. can be obtained.
Furthermore, the scanning order of each ultrasonic beam can be arbitrarily set. For example, it is also possible to first scan all the basic ultrasonic beams and then sequentially scan the auxiliary ultrasonic beams.

In FIG. 9, the endoscopic axis 40 itself is rotated to continuously observe the diagnostic site around the probe 12, or a predetermined diagnostic site is viewed as a circular section by rotating the probe 12. Another embodiment of the present invention is shown that can be displayed, with one end of the endoscopic axis 40 facing the subject 1.
The endoscope shaft 40 is connected to a rotation mechanism 48 provided outside the camera, and can rotate the endoscopic shaft 40 at a predetermined rotational speed in accordance with the drive of a motor or the like. In FIG. 9, the other end of the rotation mechanism 48 is connected to an excitation drive means (not shown) via a connector 52. Therefore, the rotation mechanism 48 rotates the endoscopic axis 4
0 is rotated in the direction of arrow A, making it possible to obtain a large amount of diagnostic information in a short period of time. Further, the probe 12 in FIG. 9 has an elongated shape, and its outer periphery is covered with an electrically insulating material 54.
It is characterized by being extremely easy to insert into the body cavity 10a.

In each of the embodiments described above, a single electronic scanning probe 12 is fixed to the tip of the endoscopic shaft 40, but in the present invention, a single electronic scanning probe 12 is fixed to the tip of the endoscopic shaft 40 as shown in FIG. As shown in FIG. It is preferable to fix it. According to this embodiment, for example, the endoscopic axis 4
When rotating at zero, the entire circumference can be scanned at once at a rotation angle of 180 degrees, making it possible to further shorten diagnosis time, and making each probe 12, 112 a probe with different characteristics. By switching between the two, it is possible to transmit and receive the ultrasonic beam optimally suited to the diagnosis site. That is, the characteristics of the probe include the curvature of its convex surface, the shape of each vibrating element, switching of excitation frequency, etc.
By switching these, it becomes possible to select the optimal ultrasonic beam.

Furthermore, in the embodiment shown in FIG.
2,112 vibration elements 16-1 to 16-n, 1
In order to reduce the number of lead wires 16-1 to 116-n, both vibrating element groups 16 and 116 are connected to each probe 1.
Commonly connected between 2 and 112, common lead wire group 4
4a is connected to the terminal 56. The common ends of both vibrating element groups 16 and 116 are led to terminals 58 and 60 as switching lead wires 44b and 44c, and both terminals 58 and 60 are switched and controlled by a switching contact 62. The excitation drive signal supplied between the terminal 64 and the terminal 56 connected to the
It will be supplied to one side. Therefore, the 10th
According to the illustrated embodiment, two sets of probes 12, 112
Despite having a built-in lead wire, the number of lead wires only needs to be increased by one compared to the conventional method, and it is possible to prevent the probe from becoming larger and the thickness of the endoscopic axis 40 from increasing due to an increase in the number of lead wires. can.

As explained above, according to the present invention, the probe inserted into the body cavity of the subject is miniaturized while
Furthermore, it is possible to display endoscopic images with a wide diagnostic field of view, and there is an advantage that diagnosis can be performed in a short time without causing pain to the subject.

[Brief explanation of drawings]

Fig. 1 is a schematic explanatory diagram showing how a general endoscopic ultrasound diagnostic device is used, and Fig. 2 shows the main parts of an endoscopic ultrasound diagnostic device using a conventional electronic scanning probe. Explanatory drawing, FIG. 3 is a main part explanatory drawing showing a preferred embodiment of the endoscopic ultrasound diagnostic apparatus according to the present invention,
3 is a perspective view showing the specific structure of the probe in FIG. 3, FIG. 5 is an explanatory diagram showing a probe suitable for the present invention and its excitation drive circuit, and FIG. An explanatory diagram showing the transmission and reception of the ultrasound beam, FIG. 7 is a circuit diagram showing an embodiment of an excitation drive circuit suitable for the present invention, and FIG. 8 is an explanation showing the transmission and reception state of the ultrasonic beam used in the present invention. 9 are schematic configuration diagrams showing another embodiment of the endoscopic ultrasonic diagnostic apparatus according to the present invention, and FIG. 10 is an explanatory diagram of main parts showing still another embodiment. 10... Subject, 10a... Body cavity, 12... Probe, 16... Vibration element, 40... Endoscopic axis, 48
... Rotating mechanism, 54 ... Electrical insulation material, 112 ...
Probe, 116... vibrating element, 200... ultrasonic beam.

Claims (1)

[Scope of Claims] 1. A contactor having a plurality of vibrating elements fixed to the tip of an endoscopic shaft inserted into a body cavity of a subject and arranged in a convex shape at equal intervals, and a predetermined program selected from the group of vibrating elements. means for exciting and driving the vibrating elements selected according to the wave transmission/reception timing at each wave transmission/reception timing; 1. An endoscopic ultrasonic diagnostic apparatus comprising a wave transmitting/receiving control circuit that performs a plurality of ultrasonic beam transmitting/receiving operations having different ultrasonic beam directivity characteristics with respect to a set of ultrasonic beams. 2 In the device according to claim 1, the wave transmission/reception control device processes and displays the ultrasonic beam reception signal assuming that the beam extension line of each sector scanning ultrasonic beam coincides with the arcuate center of the contact. An endoscopic ultrasonic diagnostic device, characterized in that it is provided to a department. 3. An endoscopic ultrasonic diagnostic device according to claim 1 or 2, wherein the contact has an elongated shape and the outer periphery is covered with an electrically insulating material. 4. The device according to any one of claims 1, 2, and 3, characterized in that a contactor rotation mechanism is provided at the outer end of the endoscopic axis, and the contactor is rotationally controlled within the body cavity. Ultrasonic diagnostic equipment for endoscopy. 5. An endoscopic ultrasonic diagnostic apparatus according to any one of claims 1, 2, 3, and 4, characterized in that a plurality of probes are provided at the tip of the endoscopic axis. 6. An endoscopic ultrasound diagnostic apparatus according to claim 5, wherein the vibrating element group of each probe is commonly connected between the probes. 7. In the device according to claim 6, the switching lead end of the vibrating element group of each probe is connected to a switching contact, and an excitation drive signal is supplied to any of the vibrating element groups by switching control of the switching contact. An endoscopic ultrasonic diagnostic device characterized by the following.