JPH04193270A - Ultrasonic diagnosis apparatus - Google Patents

Abstract

PURPOSE:To make it possible to scan the front region of an ultrasonic probe over a wide region and to make an image with high resolution by providing an ultrasonic oscillator array, an ultrasonic probe, a treating device based on an opening synthesis system and an image constituting device. CONSTITUTION:A receiving signal transferred to a receiving circuit part 8 from a microultrasonic oscillator is treated by amplification in the receiving circuit part 8 and is converted to a digital value in an A/D convertor 9 and is stored in a memory 10. This movement is repeated until all the necessary data for making an image are stored. The received signal data stored in the memory 10 are red out properly by means of a signal treating part 11 and such treatments as retardation, weighing and addition are treated on them by means of an opening synthesis system for realizing high resolution and a necessary scanning range to make image data. Synthesized image data are transferred to an image constituting part 12 and are made into video signals and are displayed on a CRT 14. A series of these movements is controlled by a control part 13 contg. a time base.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is used for transmitting, receiving and scanning ultrasonic waves with an ultrasonic probe to visualize the area in front of the ultrasonic probe.
In particular, the present invention relates to an ultrasonic diagnostic device suitable for use in diagnosing conditions in minute cavities and tubes.

Conventional technologyRecently, ultrasonic diagnostic equipment using ultra-small ultrasonic probes that can be inserted into minute cavities and tubes has been attracting attention in the medical field of the circulatory system, etc., in order to diagnose the condition of minute cavities and tubes. ing. As such an ultra-small ultrasonic probe, for example, PR
,0CEEDING OF THEIEEE VOL
76, No. 9, 1988 is known. The conventional ultra-small ultrasonic probe will be described below with reference to the drawings.

FIG. 11 is a sectional view of the tip of a conventional ultrasound probe. In FIG. 11, 110 is an ultrasonic probe, which includes a cylindrical housing 114 with a closed tip, an acoustic window 113 formed on the side of the tip of the housing 114, and an acoustic window inside the housing 114. The ultrasonic transducer 111 is disposed in front of the acoustic window 113 so that the ultrasonic transducer surface is perpendicular to the acoustic window 113, and the ultrasonic transducer 111 is disposed at an angle behind the acoustic window 113 in the housing 114. Sound wave vibrator 111
The acoustic reflection plate 112 reflects the ultrasonic waves transmitted from the acoustic window 113 to the external force of the acoustic window 113 and reflects the reflected ultrasonic waves returned from the acoustic window 113 to the ultrasonic transducer 111.

In the above configuration, the ultrasonic waves transmitted from the ultrasonic transducer 111 are reflected by the acoustic reflector 112 into the housing 114.
That is, the side force is reflected in the radial direction and passes through the acoustic window 113 toward the test region of the subject.

The ultrasonic waves reflected from the test site follow the same route as the transmission and are received by the ultrasonic transducer 111. The entire tip of the ultrasonic probe 110 and a portion thereof are configured to be rotatable, and scanning in the radial direction is performed by this rotation. The received signal is then processed by the ultrasound diagnostic apparatus main body and converted into an image.

Problems to be Solved by the Invention However, in the configuration of the conventional example as described above, since the ultrasonic waves are transmitted in the radial direction of the cylindrical housing 114, forward scanning, that is, imaging is difficult. However, there is a problem in that it is not possible to accurately judge the situation inside microcavities or tubes.

The present invention solves the problems of the prior art as described above, and is capable of scanning a wide area in front of an ultrasound probe and imaging it with high resolution. The present invention provides an ultrasonic diagnostic device that can accurately judge situations such as the By doing so, it is possible to increase the resolution and reduce the number of ultrasonic transducers, and this reduction not only makes it possible to reduce costs, but also to improve the ultrasonic transducer. It is an object of the present invention to provide an ultrasonic diagnostic apparatus that can be further miniaturized.

Means for Solving the Problems In order to achieve the above object, the technical solution of the present invention is as follows:
An ultrasonic transducer array consisting of a plurality of ultrasonic transducers that transmits ultrasonic waves forward and receives reflected ultrasonic waves, and is provided behind the ultrasonic transducer array to control transmission and reception of the ultrasonic transducers. an ultrasonic probe equipped with an electronic circuit, means for processing signals received by the ultrasonic transducer using an aperture synthesis method, and means for constructing an image in front of the ultrasonic probe using the processed data. It is something to be prepared for.

It is preferable that the signal processing means using the aperture synthesis method suppresses the grating lobes of the ultrasonic transducer array, and a weighting function can be used to suppress the grating lobes of the ultrasonic transducer array. Furthermore, in order to obtain information over a wide scanning area, the area in front of the ultrasound probe can be scanned in a fan-shaped manner.

Therefore, according to the present invention, ultrasonic waves are transmitted from at least one of the ultrasonic transducers constituting the ultrasonic transducer array to the test area in front of the ultrasonic probe, and The ultrasonic transducer receives the ultrasonic waves reflected from the area to be examined in front and converts them into electrical signals. The ultrasonic transducer used for transmission and reception is switched by an electronic circuit inside the ultrasonic probe, and by repeating the above operation, it scans the area in front of the ultrasonic probe and receives the received signal using the aperture composite force method. It can be processed and imaged. An electronic circuit having an ultrasonic transducer switching function is provided inside the ultrasonic probe by means of an IC or the like, thereby reducing the number of signal lines connected to the main body of the ultrasonic diagnostic apparatus.

In addition, in the means of signal processing using the aperture composite force formula, grating lobes that are a problem in ultrasonic transducer arrays are suppressed, and by using a weighting function for this suppression, the number of elements in the ultrasonic transducer array is reduced. Since high resolution can be achieved without increasing the number of pixels, the configuration of the control electronic circuit can be simplified.

EXAMPLES Hereinafter, examples of the present invention will be described with reference to the drawings.

First, a first embodiment of the present invention will be described.

1 to 3 show an ultrasonic diagnostic apparatus according to a first embodiment of the present invention, and FIG. 1 is a perspective view of an ultrasonic probe;
FIG. 2 is a sectional view of the ultrasound probe, and FIG. 3 is a functional block diagram of the entire ultrasound diagnostic apparatus.

In FIGS. 1 and 2, reference numeral 1 denotes an ultrasonic probe, which is equipped with a cylindrical housing 2, an ultrasonic probe provided at the tip of the housing 2, and includes an acoustic lens, a matching layer, a backing layer, etc. The ultrasonic transducer array 3 includes a transducer array 3 and an associated electronic circuit 4 provided behind the ultrasonic transducer array 3. A plurality of signal lines for transmitting control signals and transmission/reception signals are wired in the internal cavity 5 of the ultrasound probe 1 . The ultrasonic transducer array 3 is composed of a plurality of micro ultrasonic transducers, arranged so that the ultrasonic transmitting/receiving surface faces the front of the ultrasonic probe 1, and forms a linear array in the illustrated example. There is.

The related electronic circuit 4 has functions such as channel switching and switching, and can switch the ultrasonic transducers of the ultrasonic transducer array 3 when transmitting and receiving ultrasonic waves. The related electronic circuit 4 is connected to the main body of the ultrasonic diagnostic apparatus through the plurality of signal lines.

To explain the main body of the ultrasonic diagnostic apparatus, in FIG. 8 is a receiving circuit section for amplifying the electrical signals received and converted by the ultrasonic transducers of the ultrasonic transducer array 3; 9 is a receiving circuit section for amplifying the electrical signals processed by the receiving circuit section 8; A/D converter that converts into a digital signal,
10 is a memory that stores the digital signal sent from the A/D converter 9; 11 is a signal processing unit that converts the digital signal data stored in the memory 10 into data for displaying an image using an aperture synthesis method; 12; 1 includes a digital scan converter, an image composition section that converts the data processed by the signal processing section 11 into a video signal, 13 a controller section that controls each of the above parts, and 14 an image composition section 12
A CRT (CRT) that displays images using video signals sent from
cathode ray tube).

The operation of the above configuration will be described below.

First, the related electronic circuit 4 receives a control signal from the control circuit section 6.
A transmission circuit unit 7 is connected to at least one of the micro ultrasonic transducers selected in the ultrasonic transducer array 3.
An ultrasonic transmission signal is supplied from the micro ultrasonic transducer, and an ultrasonic pulse is transmitted to the front region of the ultrasonic probe 1 from this micro ultrasonic transducer. A part of the ultrasonic pulses transmitted to the front region of the ultrasound probe 1 is reflected by the object to be examined existing there, and reaches the ultrasound transducer array 3 of the ultrasound probe 1 . The ultrasonic pulse received by at least one micro ultrasonic transducer selected in the electronic circuit 4 by the control signal sent from the control circuit section 6 is converted into an electric signal, and is sent to the receiving circuit via the electronic circuit 4. The information is sent to section 8. in this way,
The electronic circuit 4 selects a channel for transmission and reception based on a control signal sent from the control circuit section 6, and can thereby scan the area in front of the ultrasound probe 1.

The received signal sent from the micro ultrasonic transducer to the receiving circuit section 8 as described above undergoes processing such as amplification in the receiving circuit section 8, and is converted into a digital quantity by the A/D converter 9. It is stored in memory 1o. This operation is repeated until all the data required for imaging has been accommodated. The received signal data stored in the memory 1° is
The image data is read out by the signal processing unit 11 and subjected to processing such as delay, weighting, and addition using an aperture synthesis method that achieves high resolution and the necessary scanning range, and becomes image data. K is sent, converted into a video signal, and displayed on the CRT 14.

These series of operations are controlled by a control g13 including a time base.

As described above, according to this embodiment, one image can be obtained by scanning the area in front of the ultrasound probe l, and high resolution and a wide scanning area can be achieved by using the aperture synthesis method. I can do it. The ultrasonic probe 1 used in this embodiment has a diameter of 2 mm or less and is suitable for use by being inserted into a minute cavity such as a blood vessel or a tube structure. Since the front of the tube can be scanned, it is possible to accurately observe conditions such as occlusion of cavities or tube structures. Furthermore, due to the dimensions of the ultrasonic probe 1, it is not possible to provide many signal lines inside it.
By providing the related electronic circuit 4 behind the ultrasonic transducer, the number of signal lines can be reduced, and further, by making the related electronic circuit 4 into an IC chip, the ultrasonic probe 1
can be made smaller. In addition, the frequency of the ultrasonic waves used is 20 MH, taking into consideration the size of the ultrasonic probe 1, cavity, tube structure, resolution, ultrasonic attenuation, etc.
From z to 40cm is appropriate, and as an ultrasonic transducer, P
It is desirable to use a polymeric piezoelectric material such as VDF.

Next, a second embodiment of the present invention will be described.

4 and 5 show an ultrasonic diagnostic apparatus according to a second embodiment of the present invention, and FIG. 4 is a cross-sectional view of an ultrasonic probe,
Figure 5 is a functional block diagram of the aperture composite power type signal processing section.
FIG. 6 is a conceptual diagram of a weighting function used during aperture synthesis in the above embodiment.

In this embodiment, the same components as in the first embodiment are given the same reference numerals, and different contents will be explained. In FIG. 4, 3a is a micro ultrasonic transducer constituting the ultrasonic transducer array 3, and the same ultrasonic transducer 3a performs transmission and reception so that complicated control is not required in the process of transmission and reception. As the related electronic circuit 4, an analog multiplexer having a switching function corresponding to the number of ultrasonic transducers 3a is used to simplify the structure and reduce the number of signal lines. Single ultrasonic transducer 3
a has a broad directivity 15 close to omnidirectional, and 1
By this transmission and reception, reflected ultrasound from a wide range in front of the ultrasound probe 1 is received, sent to the ultrasound diagnostic apparatus main body via the signal line, and processed in the same manner as in the first embodiment. , memo! It seems like it will be remembered in 1lffi. Note that reference numeral 16 in FIG. 4 indicates a fan-shaped scanning area of the ultrasonic transducer array 3.

In FIG. 5, 17 is a variable focus controller that controls the read position of the memory IO, 18I''i variable weight, 1
A multiplier 9 multiplies the read ratio data from the memory 10 by a weight 18, and an adder 20 adds the multiplication results of each multiplier 19.

Then, τ, first, the address of the received data stored in the memory 10 after transmission and reception is calculated under the control of the variable focus controller 17 according to the round trip distance from each ultrasonic transducer 3a to the imaging target point. Data at each address is read from the memory 10. Next, a multiplier 19 multiplies each data by a weight 18 that is varied according to the distance from the imaging target point to each ultrasonic transducer 3a, and an adder 20 adds the weights to each data to create an image for the imaging target point. Get data. In this embodiment, the above operation is performed for each imaging target point in the fan-shaped scanning area 16, and data for 1lIIIiI images is constructed.

In FIG. 6, 21 represents the distribution of propagation paths in consideration of transmission and reception to the imaging target point when the ultrasound transducer array 3 is a continuous ultrasound transducer, and 22
id shows a weighting function for received signal data of each ultrasonic transducer 3a. In the case of the ultrasonic transducer array 3,
In addition to normal sight lobes, grating lobes caused by the arrangement spacing of the ultrasonic transducers 3a pose a problem. In this embodiment, since the ultrasonic transducer array 3a is composed of a small number of about 10 elements at most, a major problem is whether grating lobes can be suppressed.

Assuming that the ultrasonic transducer array 3 is continuous, grating lobes can be reduced by adding a weighting function 22 that brings the actual propagation path distribution of the ultrasonic transducer array 3 closer to its propagation path distribution 21 . It becomes possible.

Assuming a two-dimensional linear ultrasonic transducer, if the one-way distance to a certain imaging target point is R, and the propagation path distribution is expressed stochastically, the following equation is obtained.

Here, Y is the distance between the straight line including the ultrasound transducer 3a and the imaging target point. The round-trip propagation path distribution is expressed as the following equation as a convolution of equation (1).

pt r (r)-p (R1)* p (r)
, , (2) Equations (1) and (2) serve as an index of the weighting function in the case of a linear array. The propagation path distribution can be calculated using a compex array or the like, and a distribution that differs depending on the shape of the ultrasonic transducer array 3 is required.

The flow of image configuration in this embodiment will be described in detail below with reference to FIGS. 7 to 10.

In FIG. 7, 71 is a composite RF line in this method, 72 is the center point of fan-shaped scanning, 73 is a point reflector, and 74 is a propagation path of transmitted and received waves corresponding to each ultrasonic transducer 41 and point reflector 73. It shows.

As shown in FIG. 7, by moving the center L point of the fan-shaped scanning area to the rear of the ultrasonic transducer, a blind spot in front of the catheter can be eliminated and a wider field of view can be achieved. Therefore, the RF multiplied signal of the received signal is synthesized as a composite RF line 71 passing through the center 72 of the fan-shaped scanning area.

FIG. 8 shows the flow of received signal processing in this method, where 81 is the received waveform data recorded in the memory when a point reflector exists at point A in the scanning area 43, and 82 is the RF waveform data at point A. Data retrieval position from memory corresponding to each ultrasonic transducer when performing double signal synthesis, 83.84
Similarly, indicates the data extraction position corresponding to point B and point 0 within the scanning area.

In this embodiment, as described above, transmission and reception of the ultrasonic transducer 41 is performed for each element, and the control thereof is performed by the analog multiplexer 44. The received signal for one element is suitably amplified by the receiving circuit section 7, then digitized by the A/D 8 and recorded in memories prepared as many times as the number of elements. FIG. 8 schematically shows the received waveform data corresponding to each ultrasonic transducer 41 when a point reflector is placed at point A in the scanning area in the case of 7 elements and 7 memories. , the relative position in the memory 9 corresponding to each element changes due to the difference in position within the scanning area 43. Retrieval of received waveform data is performed sequentially along the composite RF line 71 in FIG.

FIG. 9 is a detailed explanatory diagram of the signal processing system after the data is extracted from the received waveform memory 9, and 91 is a weight for the received wave data of each ultrasonic transducer 41 at each point in the scanning area. A weight map that records values, 92 is waveform data taken out from the memory as many times as the number of elements, 93 is synthesized via the multiplier 52 and adder 53, and the RF multiplied signal 94 is the synthesized RF multiplied signal image described above. a processing unit that compresses and detects image data to suit the dynamic range; 9;
5 is an image memory for recording image data, and 96 is a schematic representation of the image data stored in the image memory 95.

The weight values for grating lobe suppression are calculated in advance for each ultrasonic transducer 41.
is stored in The weight values corresponding to the imaging target points on the composite RF line 71 are compared for each ultrasonic transducer 41, multiplied by each image data 92 in a multiplier 52, added together in an adder 53, and processed. This is the composite RF signal value for the imaging target point inside. By performing the above-mentioned weighting and addition processing on all the image visualization target points on the composite RF line 71, the composite R for one line is
An F-fold signal 3 is constructed, and by applying this process to the entire scanning area, one screen worth of image data is stored in the image memory 95. Image data 96 in FIG. 9 is obtained when a point reflector is placed at point A in the scanning area 43 in FIG. 8, and shows that the signal of the point reflector is seen in the image data near the center. There is.

FIG. 10 shows processing after image to data configuration and an ultrasonic tomographic image, where 101 is a display area of the DSC 1102, and 103 is an ultrasonic tomographic image.

The image data 96 stored in the image memory 95 is sequentially read out and converted into a video signal by the DSC, and the CR
Displayed on T13. Since the scanning area is fan-shaped, the display area 102 is also fan-shaped, resulting in an ultrasonic tomogram @103 corresponding to the actual shape. Ultrasonic cross section in Figure 10 @103
For example, similar to FIGS. 8 and 9, this is an ultrasonic tomographic image when a point reflector exists at point A in the scanning area 43 of FIG.
A group of reflective points is displayed near the center of the display area.

As described above, in this embodiment, by using the same ultrasonic transducer for transmitting and receiving, the related electronic circuit can be simplified, and it is suitable for miniaturizing the ultrasonic probe. However, it is still possible to achieve high resolution using the aperture synthesis method, and by adding a weighting function that takes into account the propagation path distribution, grating lobes can be suppressed, making it possible to create an ultrasonic probe with a small number of ultrasonic transducers. It becomes possible to image the front area of the

DETAILED DESCRIPTION OF THE INVENTION According to the present invention, there is provided an ultrasonic transducer array comprising a plurality of ultrasonic transducers that transmit ultrasound forward and receive reflected ultrasound; an ultrasonic probe provided at the back and equipped with an electronic circuit for controlling transmission and reception of the ultrasonic transducer; a means for processing the signal received by the ultrasonic transducer using an aperture synthetic force method; and processing data of the ultrasonic probe. Since it is equipped with a means for composing an image in front of the ultrasound probe, it is possible to scan a wide area in front of the ultrasound probe and image it with high resolution. Conditions such as cavities and pipe structural forces can be accurately determined. In addition, an electronic circuit with an ultrasonic transducer switching function is installed inside the ultrasonic probe, reducing the number of signal lines connected to the ultrasonic diagnostic equipment body. Miniaturization can be achieved.

In addition, in the means of signal processing using the aperture composite force formula, the grating lobes that cause problems in the ultrasonic transducer array are suppressed, and a weighting function that takes into account the propagation path distribution is used to suppress this problem. Since high resolution can be achieved without increasing the number of elements in the ultrasonic transducer array, related electronic circuits can be further simplified. Therefore, it is possible to reduce costs and further downsize the ultrasonic probe.

[Brief explanation of the drawing]

Figures 1 to 3 show an ultrasonic diagnostic apparatus according to a first embodiment of the present invention. 1-1 Figure 1 is a perspective view of an ultrasound probe, and Figure 2 is a cross-section of the ultrasound probe. 3 and 3 are functional block diagrams of the entire ultrasonic diagnostic apparatus, FIGS. 4 and 5 show the ultrasonic diagnostic apparatus according to the second embodiment of the present invention, and FIG.
The figure is a cross-sectional view of the ultrasonic probe, Figure 5 is a functional block diagram of the signal processing section of the aperture synthesis method, Figure 6 is a conceptual diagram of the weighting function used during aperture synthesis in the above embodiment, and Figure 7 is Explanatory diagrams of the fan-shaped scanning area in the present invention, FIGS. 8 to 1
0 is a detailed explanatory diagram of the received signal processing and enclosure construction process in the present invention, and FIG. 11 is a sectional view showing an ultrasound probe in a conventional example. 1... Ultrasonic probe, 3... Ultrasonic transducer array,
3a. Ultrasonic transducer, 4. Associated electronic circuit, 5. Internal cavity, 6. Control circuit section, 7. Transmission circuit section, 8.. Receiving circuit section, 9. A/D converter, 10. ··memory,
11... Signal processing section, 12... Image composition section, 13.
... Controller section, 14. CRT, 15. Directivity of ultrasonic transducer, 16. Scanning area, 17. Variable focus controller, 185T variable weight, 19. Multiplier, 20 Adder, 21. Propagation path distribution. , 22... Weighting function, 71-- Composite RF line, 72 - Center of fan-shaped scanning area, 73- Point reflector, 74 Transmission/reception wave propagation path, 81... Waveform data, 82- Data extraction at point A. Position, 83...Data retrieval position of point B, 84
... Data extraction position of 0 point, 91 ... Weight map, 92 ... Waveform data, 93 ... Combined RF multiplied signal 94
・Processing unit, 95... Image memory, 96-・International data, 101... DSC1102・Display area, 103
Ultrasound tomogram. Name of agent: Patent attorney Akira Okaji and two others 1st
Figure 4 Figure 6 Rmin Rmax @ Henha ” Helle Gihori

Claims (4)

[Claims] (1) An ultrasonic transducer array consisting of a plurality of ultrasonic transducers that transmits ultrasonic waves forward and receives reflected ultrasonic waves; An ultrasonic probe equipped with an electronic circuit for controlling transmission and reception, means for processing signals received by the ultrasonic transducer using an aperture synthesis method, and an image in front of the ultrasonic probe is constructed using this processed data. An ultrasonic diagnostic device comprising means. (2) The ultrasonic diagnostic apparatus according to claim 1, wherein the signal processing means using an aperture synthesis method suppresses grating lobes of the ultrasonic transducer array. (3) The ultrasonic diagnostic apparatus according to claim 2, wherein a weighting function is used to suppress grating lobes of the ultrasonic transducer array. (4) The ultrasonic diagnostic apparatus according to any one of claims 1 to 3, wherein the front area of the ultrasonic probe is scanned in a fan-like manner.