JP4256984B2 - Ultrasonic diagnostic device and transducer - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an ultrasonic diagnostic apparatus and a transducer, and more particularly to two-dimensional scanning of a transmission / reception beam for forming a three-dimensional image.
[0002]
[Prior art]
In order to form a three-dimensional ultrasonic image of a living body, it is necessary to capture echo data in a three-dimensional space. Therefore, an ultrasonic probe for taking in three-dimensional echo data for mechanically scanning an electronic scanning type one-dimensional array transducer has been put into practical use. However, in the case of such an ultrasonic probe, there is a problem in that the probe shape is increased because it is necessary to accommodate a mechanical scanning mechanism inside.
[0003]
Also, it is possible to capture 3D echo data using a 2D array transducer. The two-dimensional array transducer is formed by two-dimensionally arranging a large number of vibration elements on a plane or a curved surface, and each vibration element generally functions as a transmission / reception element.
[0004]
However, since the two-dimensional array transducer is composed of an extremely large number of vibration elements, the structure is complicated and the manufacturing cost is high. In addition, the number of signal lines and the size of the transmission / reception circuit are significantly increased. For this reason, there are many problems in realizing it.
[0005]
Therefore, a sparse array transducer has been proposed. Briefly describing the array transducer, the array transducer corresponds to a normal two-dimensional array transducer obtained by thinning a large number of transducer elements in accordance with predetermined conditions. According to this sparse array transducer, the above problems can be alleviated by significantly reducing the number of vibrating elements while retaining the function of a two-dimensional array transducer.
[0006]
By the way, in a sparse array transducer or a normal two-dimensional array transducer, when one reception beam is formed for one transmission beam for each direction in the three-dimensional space, all echo data is obtained. A large number of transmissions / receptions are required before importing. Therefore, it is conceivable to form a plurality of reception beams per transmission beam.
[0007]
FIG. 7 conceptually shows the transducer 110 and one transmission beam 114 and a plurality of reception beams 112 formed thereby. Reference numeral 113 denotes a beam center axis, and the transmission beam 114 has a shape in which the cross section spreads in a circle around the center. In FIG. 7, for convenience, the cross section of the transmission beam is shown as a rectangle.
[0008]
The transducer 110 is formed by two-dimensionally arranging a plurality of ultrasonic elements. A reception beam array 150 composed of, for example, 4 × 4 (= 16) thin reception beams 112 per one thick transmission beam 114 is formed, that is, for example, 16 reception signals are obtained per transmission. The receive beam array 150 is in an overlapping relationship with the transmit beam 114.
[0009]
As shown in FIG. 8, if a reception beam array is formed each time a transmission beam is formed along the x direction and the y direction, the number of transmission / receptions is limited, but the entire three-dimensional acquisition space is limited. It is possible to capture 3D echo data. Reference numeral 200 indicates a virtual plane in which beam scanning is performed, and z indicates a vertical axis passing through the center.
[0010]
[Problems to be solved by the invention]
However, if a thick transmission beam is simply formed, the ultrasonic energy is diffused accordingly. That is, there is a problem that the ultrasonic energy per unit area becomes weak when viewed from the direction of the azimuth axis, causing deterioration in image quality.
[0011]
Further, when only the B-mode image of the desired cross section in the three-dimensional space is formed while using the same ultrasonic probe (transmitter / receiver), there is a problem that the above transmission / reception method is wasteful. In other words, in this case, for example, only 4 reception beam trains along the x direction or the y direction are used out of 4 × 4 reception beams, so that the transmission efficiency and the reception efficiency are deteriorated. There is. In addition, existing ultrasonic diagnostic apparatuses (particularly digital scan converters) perform processing suitable for a one-dimensional received signal array obtained by scanning an ultrasonic beam in a one-dimensional direction. There is a problem that it is difficult to adapt a two-dimensional received signal array.
[0012]
The present invention has been made in view of the above-described conventional problems, and an object of the present invention is to realize an accurate measurement while reducing the number of transmission / reception in an ultrasonic diagnostic apparatus.
[0013]
Another object of the present invention is to provide an efficient transmission / reception system suitable for both three-dimensional image processing and tomographic image processing.
[0014]
[Means for Solving the Problems]
(1) In order to achieve the above object, the present invention provides a transducer having a plurality of transmitting elements and a plurality of receiving elements arranged in a predetermined pattern, and supplying a transmission signal to the plurality of transmitting elements. A means for controlling, a transmission beam forming means for forming a thick transmission beam having a flat cross section, and a means for executing a phasing addition process on reception signals from the plurality of reception elements, the transmission beam Receiving beam forming means for forming a receiving beam array composed of a plurality of thin receiving beams arranged in the major axis direction of the flat cross section with an overlapping relationship.
[0015]
According to the above configuration, a thick transmission beam having a flat cross section is formed, and a plurality of reception beams arranged in the major axis direction of the flat cross section are formed so as to overlap with the transmission beam. Desirably, the plurality of receive beams constitute a one-dimensional receive beam train.
[0016]
According to the present invention, since a plurality of received signals can be obtained per transmission, the total number of times of transmission and reception can be reduced, and the transmission beam has a flat cross section, so that compared with a case where a thick beam having a circular cross section is simply formed. , Can concentrate ultrasonic energy. That is, it is possible to obtain the advantages of both transmission / reception time reduction and image quality improvement.
[0017]
In particular, since a reception signal array arranged in the long axis direction can be acquired, for example, reception obtained when a probe for capturing three-dimensional echo data that combines electronic scanning and mechanical scanning as described above is used. The received signal group can be acquired with the same arrangement as the signal group arrangement, so that various conventional image processing methods can be applied as they are, or even if the method needs to be changed, the content of the change should be kept to a minimum. Can do.
[0018]
Preferably, the reception beam forming unit includes a plurality of phasing addition units provided for each reception beam. According to this configuration, reception signals acquired simultaneously in parallel can be processed in parallel.
[0019]
Preferably, the transmission beam forming means performs two-dimensional scanning of the transmission beam, and the reception beam forming means forms a row of reception beams for each transmission beam, and a plurality of reception signals acquired along with the two-dimensional scanning. An image processing means for forming a three-dimensional image based on the above is provided. As the three-dimensional image processing method, various methods can be exemplified, and for example, an image processing method based on a volume rendering method may be used. In this case, sequential image processing may be performed on the echo data along the ultrasonic beam.
[0020]
Preferably, the transmission beam forming means raster scans the transmission beam in parallel with the long axis direction of the flat cross section. According to this configuration, reception signals can be acquired in the same order as when the B-mode tomographic plane is scanned in parallel or oscillating.
[0021]
Desirably, a plurality of transmitting elements are dispersedly arranged in a transmitting element area extending in a direction orthogonal to the major axis direction of the flat cross section on the transducer. Desirably, a plurality of receiving elements are dispersedly arranged in a receiving element area extending from the center of the transmitting element area on the transducer. Preferably, transmitting elements and receiving elements are densely arranged in the overlapping area of the transmitting element area and the receiving element area. Preferably, the plurality of transmitting elements and the plurality of receiving elements are elements dedicated to transmission and reception, respectively.
[0022]
(2) In order to achieve the above object, the present invention provides a transducer in which a plurality of transmitting elements and a plurality of receiving elements are arranged, wherein the plurality of transmitting elements are along an axis passing through the origin. The plurality of receiving elements are distributed and arranged in a receiving element area extending from the origin.
[0023]
Preferably, the plurality of transmitting elements and the plurality of receiving elements are arranged in a pattern having no line symmetry.
DETAILED DESCRIPTION OF THE INVENTION
Preferred embodiments of the present invention will be described below with reference to the drawings.
[0024]
FIG. 1 shows the concept of a transmission / reception system according to the present invention. In FIG. 1, a transducer 10 is formed by arranging a plurality of transmission elements and a plurality of reception elements on a transmission / reception surface. Here, the arrangement pattern of the transmitting element and the receiving element will be described later with reference to FIGS.
[0025]
The virtual plane 200 is a virtual plane for explaining the two-dimensional scanning of the ultrasonic beam, and is drawn as a plane parallel to the transmission / reception surface of the transducer 10.
[0026]
In the present embodiment, a thick transmission beam 12 having a flat cross section is formed by the transducer 10. In addition, a plurality of thin reception beams 14 are formed simultaneously with the overlapping relationship with the transmission beam 12. Incidentally, the formation of each ultrasonic beam can be easily realized by using a so-called electronic focusing technique. In this case, in the simultaneous formation of a plurality of reception beams, a plurality of reception circuits provided in parallel as described later are provided. Used.
[0027]
In FIG. 1, for the sake of convenience, the transmission beam 12 has a fan beam shape. However, in this embodiment, the transmission beam 12 has a flat elliptical cross section, which will be described later with reference to FIG. 2. I will explain.
[0028]
In the present embodiment, a reception beam array 50 as, for example, eight one-dimensional reception beams included in one transmission beam 12 is formed, and the reception beam array is formed along the x direction in FIG. 50 is formed. The transmission beam 12 is electronically scanned in the array direction of the reception beam array 50, that is, the x direction. When transmission / reception for one scanning line along one x direction on the virtual plane 200 is completed, the scanning line of the transmission beam 12 is scanned. Is shifted by one step in the y direction, and transmission / reception similar to the above is executed, and this is repeated. That is, the transmission beam is raster scanned on the virtual plane 200.
[0029]
Therefore, a B-mode tomographic plane can be formed by one scan of the transmission beam 12 in the x-direction, and a plurality of B-mode tomographic planes can be formed in the y-direction by the raster scanning described above. That is, it is possible to form a three-dimensional echo data capturing space.
[0030]
FIG. 2 shows a conceptual cross section of the transmission beam and the reception beam. FIG. 2A shows a beam cross section according to the transmission / reception system of the comparative example shown in FIGS. 7 and 8, and FIG. 2B shows a beam according to the transmission / reception system of the present embodiment. The concept of a cross section is shown.
[0031]
In the comparative example, as shown in (A), a circular thick transmission beam section 112A is formed, and for example, 4 × 4 reception beam sections 114A are set therein.
[0032]
On the other hand, in the present embodiment, an elongated elliptical transmission beam cross section 12A flattened along one direction is formed, and a plurality of reception beam cross sections 14A are set while being included therein.
[0033]
Incidentally, in FIG. 2, the direction perpendicular to the paper surface coincides with the central axis (Z direction) of the transmission beam 12, where the X direction is the azimuth direction, which coincides with the x direction shown in FIG. The Y direction is the elevation direction, and the Y direction is a projection of the Y direction on the virtual plane 200. The X direction and the Y direction represent two axes orthogonal to the beam axis of the transmission beam.
[0034]
As is clear from the above description, according to the present embodiment, since a plurality of received signals can be acquired per transmission, the number of times of transmission / reception is significantly reduced compared to the case where transmission / reception is performed once for each direction. It becomes possible. In addition, the transmission beam can be concentrated along one direction instead of spreading the transmission beam evenly as shown in the comparative example, so that the problem of sensitivity degradation due to dispersion of ultrasonic energy can be dealt with. It is. In addition, since the finally obtained reception signal array has the same arrangement as that of the conventional B-mode tomographic plane, the reception signal processing and image processing executed in the existing ultrasonic diagnostic apparatus are basically performed. It is possible to obtain the advantage that it can be applied as it is.
[0035]
Incidentally, the transducer 10 shown in FIG. 1 is configured by an ultrasonic probe formed by two-dimensionally arranging a plurality of vibration elements. Here, since the number of vibrating elements constituting the transducer 10 is large, the transmission / reception process is considerably complicated. Therefore, in the present embodiment, the sparse transducer 10 described above is used, and the arrangement pattern of the transmitting elements and the receiving elements according to the principle is shown in FIG. 3 in comparison with the comparative example.
[0036]
3A, in the transducer 110 in the comparative example, a transmission element area 122 and a reception element area 124 are set on the transmission / reception surface 120 thereof. The transmission element area 122 is a circular area having a small radius, and a plurality of transmission elements are dispersedly arranged therein.
[0037]
The receiving element area 124 has a larger diameter than the transmitting element area 122, and a plurality of receiving elements are dispersedly arranged therein. Incidentally, the transmitting element area 122 overlaps with the central portion of the receiving element area 124. A transmission beam 12 and a plurality of reception beams 14 as shown in FIG. 1 are formed by such an arrangement pattern of transmission / reception elements.
[0038]
On the other hand, in the present embodiment, as shown in FIG. 3B, a transmission element area 22 and a reception element area 24 as shown are set on the transmission / reception surface 20 of the transducer 10. Here, as understood from comparison with FIG. 2B, the transmission element area 22 extends along the minor axis direction orthogonal to the major axis of the flat transmission beam cross section, that is, the transmission beam cross section. The minor axis direction corresponds to the major axis direction of the transmitting element area 22. In other words, the major axis direction of the cross section of the transmission beam coincides with the minor axis direction of the transmission element area 22 . When achieving the convergence of the ultrasonic beam by the electronic focus techniques, it is desirable to set the wide opening in a direction to enhance the convergence is the intersection relationship elliptical shape as mentioned above is set. Although the transmission element area 22 is set to have an almost elliptical shape in the present embodiment, various types of changes such as being closer to a rectangular shape can be considered.
[0039]
In the elliptical receiving element area 24 shown in FIG. 3B, the major axis direction is set along the array direction of the receiving beam array 50 shown in FIG. 1, that is, the X direction, and is orthogonal to the x direction. The y-axis direction is the minor axis direction. On the y-axis direction, the width of the receiving element area 24 in the minor axis direction is set smaller than the length of the transmitting element area 22 in the major axis direction. Incidentally, as shown in the figure, the midpoints of both areas 22 and 24 coincide.
[0040]
FIG. 4 shows an example of element arrangement when the transmitter / receiver shown in FIG. 2 (B) is specifically realized. In FIG. 1, the ◯ symbol indicates the transmitting element, and the X symbol indicates the reception. The element is shown. Here, for example, the transmitting element and the receiving element are each 48 elements, and in this case, each element is composed of a piezoelectric body, and the pitch is 0.35 mm. As shown in the figure, in the overlapping portion of the transmitting element area 22 and the receiving element area 24 shown in FIG. 3B, the transmitting elements and the receiving elements are dense, and in other regions, the receiving elements or the transmitting elements are dense. Are arranged separately.
[0041]
In the present embodiment, each vibration element is an element dedicated to reception and an element dedicated to transmission. However, a part of the elements may be used for both transmission and reception.
[0042]
In FIG. 4, in accordance with the sparse principle, both the transmitting element pattern and the receiving element pattern are asymmetric with respect to the horizontal axis and the vertical axis. This is because side lobes are emphasized when there is symmetry.
[0043]
Next, the ultrasonic diagnostic apparatus according to this embodiment to which the above-described transmission / reception method is applied will be described with reference to FIG. FIG. 5 is a block diagram showing the overall configuration. The transducer 10 is composed of an ultrasonic probe inserted into the body surface or body cavity, and the transducer 10 is composed of the transmitting element group 30 and the receiving element group 32 as described above. Is done. As shown in FIG. 4, each element is disturbed on the transmission / reception surface, but in FIG.
[0044]
The transmission circuit 34 is a circuit for supplying a transmission signal to the transmission element group 30. Specifically, a predetermined delay time is applied to each transmission signal output from the transmission circuit 34 under the control of the scanning control unit 36. By setting, a desired transmission beam pattern can be formed in a desired direction. Here, the transmission beam 12 is raster scanned on the virtual plane 200 as shown in FIG.
[0045]
In the present embodiment, a plurality of reception circuits 38 are provided in parallel by the number of reception beams formed per transmission. That is, a reception signal array composed of a plurality of reception signals output from the reception element group 32 is input to each reception circuit 38 in parallel, and a reception beam in charge is formed in each reception circuit 38. Specifically, each receiving circuit 38 is configured by a circuit that performs phasing addition of the received signal, and is configured by an amplifier and a delay circuit that are provided in the same number as the received signal, an adder that synthesizes the delayed received signal, and the like. The Of course, it is also possible to form a plurality of reception beams as a result by switching and using one reception circuit in a time division manner.
[0046]
The selector 40 is a circuit for selecting the reception signal after phasing addition output from each reception circuit 38 and outputting it to the 3D memory 42. That is, the echo data acquired in the three-dimensional data capture space is stored in the 3D memory 42. The stored image is shown in FIG.
[0047]
In FIG. 6, the 3D memory space 42 </ b> A is configured by a plurality of scanning planes 202, and each scanning plane 202 is configured by a plurality of reception beam arrays 50. The reception beam array 50 is aligned along the x direction, and when the transmission beam is scanned in the x direction, the reception beam array 50 is formed by the number of the transmission beams. Thus, one scanning plane 202 is configured. When the scanning line of the transmission beam is shifted in the y direction according to the raster scanning, the scanning plane 202 is formed in the same manner as described above, and when the plurality of scanning planes 202 are finally formed, all the three-dimensional spaces in the three-dimensional space are formed. Echo data capture is complete.
[0048]
As can be understood from the above description, for example, if the transmission beam is scanned only once in the x direction, one scanning plane 202 similar to the conventional B-mode tomographic plane can be formed, and a B-mode tomographic image or the like can be formed as it is. Can be formed and displayed. Accordingly, it is possible to further extend it to three-dimensional data processing while maintaining the conventional signal processing method as it is. Such an image is executed by the image processing unit 44 shown in FIG. 5, where the image processing unit 44 is constituted by a digital scan converter (DSC) and an image processing unit. The image processing unit 44 forms a desired tomographic image, three-dimensional image, or the like. In the three-dimensional image processing, various methods can be applied, and for example, it is possible to construct a three-dimensional image viewed from the viewpoint set by the viewpoint setting unit 45, for example. In that case, image processing based on a volume rendering method or the like may be applied. The ultrasonic image formed in this way is displayed on the display unit 46.
[0049]
【The invention's effect】
As described above, according to the present invention, it is possible to realize accurate measurement while reducing the number of times of transmission and reception in the ultrasonic diagnostic apparatus. In addition, according to the present invention, an efficient transmission / reception method suitable for both three-dimensional image processing and tomographic image processing can be realized.
[Brief description of the drawings]
FIG. 1 is a conceptual diagram showing a concept of a transmission / reception system according to the present invention.
FIG. 2 is a conceptual diagram showing a cross section of an ultrasonic beam.
FIG. 3 is a conceptual diagram showing a transmitting element area and a receiving element area on a transmission / reception surface.
FIG. 4 is a diagram showing an arrangement pattern of transmitting elements and receiving elements in the transducer according to the present embodiment.
FIG. 5 is a block diagram showing an overall configuration of an ultrasonic diagnostic apparatus according to the present embodiment.
FIG. 6 is a conceptual diagram showing a data space in a 3D memory.
FIG. 7 is a conceptual diagram showing a transmission / reception method in a comparative example.
FIG. 8 is a conceptual diagram showing a transmission / reception method in a comparative example.
[Explanation of symbols]
10 Transmitter / Receiver, 12 Transmit Beam, 14 Receive Beam, 50 Receive Beam Array, 200 Virtual Plane.

Claims (10)

A transducer having a plurality of transmitting elements and a plurality of receiving elements arranged two-dimensionally in a predetermined pattern;
Means for controlling the supply of transmission signals to the plurality of transmission elements, a transmission beam forming means for forming a thick transmission beam having a flat cross section;
A means for performing phasing addition processing on reception signals from the plurality of reception elements, the reception beam comprising a plurality of thin reception beams arranged in a major axis direction of the flat cross section with a relationship overlapping with the transmission beam Receiving beam array forming means for forming an array;
Only including,
A plurality of transmitting elements are arranged in a transmitting element area extending in a direction orthogonal to the major axis direction of the flat cross section of the transmission beam on the transmission / reception surface of the transducer,
On the transmission / reception surface of the transducer, a plurality of reception elements are arranged in a reception element area extending from the center of the transmission element area.
An ultrasonic diagnostic apparatus. The apparatus of claim 1.
The ultrasonic diagnostic apparatus, wherein the reception beam array forming unit includes a plurality of phasing addition units provided for each reception beam. The apparatus of claim 1.
The transmission beam forming means scans the transmission beam two-dimensionally,
The reception beam array forming means forms a reception beam array for each transmission beam,
An ultrasonic diagnostic apparatus comprising image processing means for forming a three-dimensional image based on a plurality of reception signals acquired in association with the two-dimensional scanning. The apparatus of claim 1.
The ultrasonic diagnostic apparatus, wherein the transmission beam forming unit performs raster scanning of the transmission beam in parallel with the long axis direction of the flat cross section. The apparatus of claim 1.
The plurality of transmission elements are distributed in the transmission area,
The plurality of receiving elements are arranged in a distributed manner in the receiving area.
An ultrasonic diagnostic apparatus. The apparatus of claim 5.
The ultrasonic diagnostic apparatus, wherein the plurality of transmitting elements and the plurality of receiving elements are distributed in a pattern having no line symmetry . The apparatus of claim 1 .
An ultrasonic diagnostic apparatus, wherein transmitting elements and receiving elements are densely arranged in an overlapping area in the transmitting element area and the receiving element area. The apparatus of claim 7.
The ultrasonic diagnostic apparatus, wherein the plurality of transmitting elements and the plurality of receiving elements are elements dedicated to transmission and reception, respectively. A transducer in which a plurality of transmitting elements and a plurality of receiving elements are arranged,
The transmitter / receiver forms a reception beam array including a plurality of thin reception beams that form a thick transmission beam having a flat cross section and that are arranged in a major axis direction of the flat cross section of the transmission beam in a relationship overlapping with the transmission beam. A transducer to form,
The plurality of transmission elements are dispersedly arranged in a transmission element area extending along a predetermined axis passing through the origin, and the predetermined axis is a direction orthogonal to the major axis direction of the flat cross section of the transmission beam,
The plurality of receiving elements, transducer, characterized in that it is distributed to the receiving device in an area extending from the origin. The transducer according to claim 9, wherein
The transmitter / receiver, wherein the plurality of transmitting elements and the plurality of receiving elements are arranged in a pattern having no line symmetry.

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