JP4944582B2 - Ultrasonic diagnostic equipment - Google Patents

Description

  The present invention relates to an ultrasonic diagnostic apparatus, and more particularly to an ultrasonic diagnostic apparatus that performs correlation processing.

  A three-dimensional echo data capturing space (three-dimensional space) can be formed by moving the scanning surface formed by electronic scanning of the ultrasonic beam. Specifically, volume data is acquired from a three-dimensional space, and the volume data is composed of a plurality of scanning plane data (or frame data). A three-dimensional image can be formed by applying a rendering process to the volume data. The ultrasonic beam is usually formed by a 1D array transducer provided in the ultrasonic probe, and the scanning surface is configured by electronic scanning of the ultrasonic beam as described above. The three-dimensional space can be formed by moving the ultrasonic probe or the array transducer. In this case, one that mechanically scans an ultrasonic transducer and one that manually scans an ultrasonic probe are known. It is also possible to form a three-dimensional space using a 2D array transducer.

  When the ultrasonic transducer is mechanically scanned, a scanning mechanism and a position detector are provided. In the case of such a configuration, the structure of the ultrasonic probe is complicated accordingly. On the other hand, when the ultrasonic probe is manually scanned along the body surface, such a mechanism is not necessary, but the position and orientation of each scanning plane must be specified accurately. Detection of the target position is required. Therefore, it is conceivable that a magnetic sensor for detecting spatial coordinates is provided in the ultrasonic probe, and the coordinate information is acquired by the magnetic sensor in the process of moving the ultrasonic probe in the magnetic field. Mechanism is indispensable.

  In Patent Document 1, two scanning planes (biplanes) that are orthogonal to each other are formed by an array transducer, and a two-dimensional motion vector is obtained by executing a correlation calculation between frames for each scanning plane. A method for obtaining a three-dimensional motion vector by combining two-dimensional motion vectors for each is described. However, the variable control of the scanning surface shape is not described. Patent Documents 2-5 disclose a technique for forming a large tomographic image by connecting a plurality of tomographic images in the plane direction.

JP 2005-185336 A US Pat. No. 5,782,766 US Pat. No. 6,416,477 US Pat. No. 6,159,152 US Patent No. 6730031

  When matching processing (correlation processing) is performed between scan planes (between scan plane data), if the scan plane or tissue moves relatively in a direction intersecting the plane direction instead of the plane direction, the correlation process is performed. Difficult or impossible. More specifically, in the correlation process, the template image acquired in the nth frame is compared with each image area set on the n + 1th frame, but it corresponds to the movement of the scanning plane in the depth direction. Since the image comparison cannot be performed in principle, if the scanning plane or the tissue moves relatively in the direction, it is difficult to follow up the observation. Of course, there are cases where the matching process can be performed from the continuity of the tissue even if movement occurs in the depth direction. However, the reliability of the processing result cannot be increased. Such a problem occurs not only when the scanning plane is moved to acquire three-dimensional volume data but also when the tissue itself moves.

  An object of the present invention is to eliminate or reduce a problem caused by a relative movement of a scanning plane or a tissue in a direction different from the plane direction of the scanning plane when correlation processing is performed between the scanning planes.

  The present invention executes a correlation process between a transmission / reception unit that repeatedly forms a scanning plane by ultrasonic transmission / reception, and temporally different scanning plane data obtained by the ultrasonic transmission / reception, and obtains a correlation processing result. Correlation processing means to obtain and means for controlling the formation of the scanning surface, and in the first operation mode, a thin scanning surface is repeatedly formed by an ultrasonic beam having a thin beam shape, and the correlation processing is executed. The second operation mode includes control means for repeatedly forming at least one thick scanning surface by an ultrasonic beam having a thick beam shape.

  According to the above configuration, in the second operation mode, the thick scanning surface is repeatedly formed by the ultrasonic beam having a thick beam shape. Therefore, even if the tissue or the scanning surface moves in a direction different from the surface direction of the scanning surface. Thus, significant correlation processing can be continuously performed between the scanning plane data. That is, the conventional problem can be solved or reduced. Specifically, since the echo data component in the front-rear direction (depth direction) of the scan plane is captured in the scan plane data obtained by forming the thick scan plane, a correlation is established between the two scan plane data. Increase the possibility. In the second operation mode, a plurality of scanning planes that intersect each other may be formed simultaneously or in a time-division manner, but only one scanning plane may be formed. Although the second operation mode is basically a mode for performing correlation processing, a thin scanning surface may be formed in addition to a thick scanning surface in the second operation mode. The second operation mode is basically a mode in which correlation processing is not performed (or the above problem does not occur). The scan plane data to be subjected to correlation processing may be transmission / reception frame data or image frame data.

  Preferably, in the ultrasonic beam having the thick beam shape, the beam size in the direction orthogonal to the beam scanning direction is larger than the beam size in the beam scanning direction. That is, it is desirable to increase the beam size in the thickness direction of the scanning plane to improve the establishment of correlation processing, and to reduce the beam size in the plane direction of the scanning plane to give priority to resolution. Preferably, a cross section of the ultrasonic beam having the thick beam shape has a flat shape.

  Preferably, in the second operation mode, the first scanning surface and the second scanning surface intersecting each other are repeatedly formed, and both the first scanning surface and the second scanning surface are the thick scanning surface.

  Preferably, in the second operation mode, a third scanning plane different from the first scanning plane and the second scanning plane is repeatedly formed, and the third scanning plane is a thin scanning plane. If the third scanning plane is a scanning plane for image formation, it is a thin scanning plane, so that high image quality can be obtained. Preferably, the transmission / reception unit includes a 2D array transducer, and a wide weighting characteristic is set in the first direction on the 2D array transducer when the ultrasonic beam having the thick beam shape is formed. A narrow weighting characteristic is set in the second direction.

  As described above, according to the present invention, when correlation processing is performed between scanning planes, problems that occur when the scanning plane or tissue moves in a direction different from the plane direction of the scanning plane can be solved or reduced.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described with reference to the drawings.

  (A) Description of basic configuration of ultrasonic diagnostic apparatus

  FIG. 1 shows an embodiment of an ultrasonic diagnostic apparatus according to the present invention, and FIG. 1 is a block diagram of the ultrasonic diagnostic apparatus.

  In this embodiment, the probe 10 has a 2D array transducer formed by two-dimensionally arranging a plurality of vibration elements. An ultrasonic beam is formed by the 2D array transducer, and the ultrasonic beam can be electronically scanned in the first direction and the second direction. That is, a three-dimensional data capturing space (volume space) can be formed. As an electronic scanning method, electronic linear scanning, electronic sector scanning, and the like are known. In this embodiment, the probe 10 is held by the user, and the user manually scans the probe 10 on the body surface while maintaining the state where the wave transmitting / receiving surface of the probe 10 is in contact with the surface of the living body. This makes it possible to capture echo data over a wide three-dimensional space in the body. In such manual scanning, a first scanning surface and a second scanning surface orthogonal to each other are repeatedly formed. That is, the probe 10 is manually scanned while biplane formation is sequentially executed.

  As will be described later, correlation processing for motion detection is applied between frames in manual scanning of the probe 10, but the above correlation processing can also be applied when the target tissue moves while the probe is fixed.

  The transmission / reception unit 12 functions as a transmission beamformer and a reception beamformer. A plurality of transmission signals are supplied from the transmission / reception unit 12 to the 2D array transducer. In addition, a plurality of reception signals output from the 2D array transducer are input to the transmission / reception unit 12 and a phasing addition process is performed on these reception signals. In this case, the transmission beam and the reception beam are formed for each scanning plane. Usually, the first scanning plane and the second scanning plane are alternately formed, and the transmission / reception unit 12 performs a time division operation corresponding to each scanning plane. Of course, if the transmission frequency is different for each scanning plane, the first scanning plane and the second scanning plane can be formed simultaneously. In any case, the transmission / reception unit 12 outputs the first frame data corresponding to the first scanning plane and the second frame data corresponding to the second scanning plane to the signal processing unit 14. Each frame data is composed of a plurality of beam data, and each beam data is composed of a plurality of echo data arranged in the depth direction. The signal processing unit 14 executes a known process such as a detection process or a logarithmic compression process. Each frame data processed by the signal processing unit 14 is output to the probe motion measurement unit 15.

  In the present embodiment, in an operation mode in which correlation processing for motion detection is performed, as will be described later, a thick ultrasonic beam having a flat cross section is scanned. A second scanning surface is formed. However, in a normal operation mode in which correlation processing for motion detection is not performed, a thin ultrasonic beam is scanned as usual to form a thin scanning plane. In the operation mode in which the correlation process is performed, a third scanning plane as a thin scanning plane different from the first scanning plane and the second scanning plane as a thick scanning plane may be formed.

  The probe motion measurement unit 15 includes a coordinate conversion unit 16, correlation units 18 and 20, and a vector calculation unit 22 as illustrated. The probe motion measurement unit 15 is a module that performs correlation calculation between frames for each scanning plane and calculates three-dimensional motion information based on the motion information obtained for each scanning plane. That is, it is possible to specify the position of each scanning plane by image processing. When manual scanning is performed, the manual scanning speed varies depending on each user, and the influence of camera shake or respiratory motion may be considered. However, according to the present embodiment, each data is acquired using image processing after capturing each data. As a result, proper volume data can be reconstructed as will be described later.

  In this embodiment, the probe motion is measured. Of course, it is possible to measure the motion of the target tissue using the same principle. That is, the probe motion measuring unit 15 measures the relative motion between the probe and the target tissue (particularly the target site). Since a thick scanning plane is formed on the premise of the correlation calculation, even if a relative motion component is generated in a direction orthogonal to the scanning plane, the problem that the correlation processing is interrupted can be prevented or reduced.

  The probe motion measuring unit 15 will be specifically described. In this embodiment, two systems of arithmetic units are provided corresponding to each of the first scanning plane and the second scanning plane, but it is also possible to provide a common arithmetic unit and operate it in a time-sharing manner. is there. According to such a configuration, an advantage that the circuit scale of the apparatus can be reduced can be obtained. In the example shown in FIG. 1, the coordinate conversion unit 16 includes two digital scan converters (DSC) 36 and 38 arranged in parallel. The DSCs 36 and 38 are modules for constructing tomographic image data based on frame data acquired according to the transmission / reception coordinate system. That is, it has a coordinate conversion function and a data interpolation function. Here, the frame data corresponding to the first scanning plane is processed by the DSC 36, and the frame data corresponding to the second scanning plane is processed by the DSC 38.

  The correlation unit 18 is a circuit that processes tomographic image data corresponding to the first scanning plane output from the DSC 36. In the present embodiment, correlation calculation is performed between frames, that is, between two tomographic image data adjacent in time series order. In this case, as described later, an attention area is set in one tomographic image data, a search area corresponding to the attention area is set on the other tomographic image data, and the contents of the attention area in the search area are set. By searching for the most matching area position, it is possible to determine the parallel movement amount and the rotational movement amount between the two frames.

  Specifically, the correlator 18 includes two frame memories 40 and 42, a subtractor 44, an accumulator 46 and a minimum value detector 48. The frame memory 40 stores the current tomographic image data, and the frame memory 42 stores the previous tomographic image data. Here, it is also possible to perform a correlation calculation in real time on sequentially input data without providing the frame memory 40. The differentiator 44 performs a difference calculation between frames in units of pixel data. The difference value is integrated over the entire frame at the integrated value 46. The integration result, that is, the integrated value is input to the minimum value detector 48. By fixing one tomographic image and calculating the above integrated value while sequentially moving the other tomographic image in parallel, the minimum value of these integrated values (or the case where the correlation is greatest) ) It is possible to specify the amount of parallel movement. This process itself is known. By applying the same method, that is, by obtaining one integrated value while fixing one tomographic image data and sequentially rotating the other tomographic image data, the rotational movement amount can also be obtained. The identification of the parallel motion component and the rotational motion component in the first scanning plane is executed by the in-plane motion component calculation unit 60 described later. The correlator 20 has the same configuration as the correlator 18 described above. The correlation unit 20 calculates information for obtaining a parallel motion component corresponding to the second scanning plane and information for obtaining a rotational motion component.

  The vector calculation unit 22 includes in-plane motion component calculation units 60 and 62 and a motion vector calculation unit 64. The in-plane motion component calculation unit 60 obtains the parallel motion component and the rotational motion component between the frames as described above based on the correlation result output from the correlation unit 18 for the first scanning plane. Each of these motion components corresponds to two-dimensional vector information. Similarly, the in-plane motion component calculating unit 62 calculates the parallel motion component and the rotational motion component between frames for the second scanning plane. Then, the motion vector calculation unit 64 obtains three-dimensional motion information based on various motion components obtained for the first scan plane and the second scan plane. The three-dimensional motion information is three-dimensional parallel motion information and rotational motion information between frames. Those pieces of information are sent to the space arrangement unit 28 described later. In the present embodiment, such information is also sent to the transmission / reception control unit 66. Furthermore, when the purpose is to observe the motion information of the target tissue instead of the probe, it is conceivable to display the parallel motion information and the rotational motion information on the screen or use them in other control calculations.

  The tomographic image data corresponding to each scanning plane output from the DSCs 36 and 38 is also output to the selector 24. The selector 24 selects tomographic image data on any scanning plane and outputs it. In this case, the selection target may be indicated by the user, or a scanning plane that is as orthogonal as possible to the moving direction of the probe may be automatically selected. Further, the third scanning plane is formed at a position different from the first scanning plane and the second scanning plane, the corresponding tomographic image data is calculated in the DSC 39, and the tomographic image data obtained thereby is included in the selection target. May be.

  The tomographic image data for each frame output from the selector 24 is stored in the frame data string memory 26. The frame data string memory 26 stores a plurality of frame data (tomographic image data as scanning plane data) in chronological order. However, as indicated by a broken line, the selected tomographic image data may be sent immediately to the spatial arrangement unit 28 to spatially map the tomographic image data. In other words, the volume data configuration process described later can be performed in real time, or can be performed after manual scanning is completed.

  The spatial arrangement unit 28 specifies the spatial position of each scanning plane based on the three-dimensional motion information output from the motion vector calculation unit 64. Specifically, the coordinates of each scanning plane in the absolute coordinate system corresponding to the memory storage space are specified, and the tomographic image data is written at an address corresponding to the coordinates in the volume data memory 30. If such processing is repeated for each tomographic image data, it is possible to write a plurality of tomographic image data with an appropriate positional relationship on the volume data memory 30, that is, to reconstruct appropriate volume data. Is possible.

  The rendering unit 32 executes a three-dimensional image forming process based on, for example, a volume rendering method on the volume data described above, thereby forming a three-dimensional image. The image data is sent to the display unit 34. Incidentally, an arbitrary tomographic image or the like may be formed instead of the three-dimensional image. In any case, even if the tomographic image data sequence obtained by manual scanning has an irregular arrangement, according to the present embodiment, it is possible to specify appropriate coordinates for each tomographic image data by image processing. Therefore, there is an advantage that volume data can be obtained by appropriately rearranging them.

  The transmission / reception control unit 66 performs operation control of the transmission / reception unit 12. In the present embodiment, the first scanning surface and the second scanning surface are repeatedly formed while maintaining a preset angular relationship. However, based on the three-dimensional motion information calculated as described above, the scanning is performed. It is also possible to dynamically change the position of the surface. For example, the scanning plane for tomographic image formation may be repeatedly formed so that the direction of the surface matches the traveling direction of the probe. Alternatively, the third scanning surface may be repeatedly formed together with the first and second scanning surfaces so as to satisfy such a condition. Incidentally, a cross array vibrator having a cross shape can be used instead of the 2D array vibrator. Alternatively, other types of probes can be used as long as three-dimensional motion information can be obtained.

  FIG. 2 shows a first scanning plane A and a second scanning plane B. In the illustrated example, fan-shaped first and second scanning surfaces A and B are formed by electronic sector scanning. These scanning planes A and B are formed with an orthogonal relationship as shown. Incidentally, it is also possible to form the three-dimensional echo data capturing space V by scanning the ultrasonic beam in the first scanning direction and the second scanning direction. In the calculation of the three-dimensional motion information, it is desirable that the two scanning planes A and B are in an orthogonal relationship, but if the angular relationship between them is known, the three-dimensional motion information is calculated even if it is not necessarily an orthogonal relationship. be able to.

  3 and 4 show the concept of correlation calculation between frames. Incidentally, in the correlation calculation, a local region of interest is set in the previous frame, a search region is set so as to surround the same region as the region of interest in the next frame, and a matching region having the same shape as the region of interest is included in the search region. Are sequentially set while changing their positions, and a correlation calculation is performed at each position. 3 and 4, R1 indicates the previous frame, and R2 indicates the subsequent frame. FIG. 3 shows parallel movement vectors between frames, and FIG. 4 shows rotational movement vectors between frames. The calculation for obtaining such vector information is known.

  FIG. 5 conceptually shows a method for calculating three-dimensional parallel motion information as three-dimensional motion information. XYZ indicates an absolute coordinate space, and xyz indicates a relative coordinate space (a coordinate space based on the probe). A indicates the first scanning plane, and B indicates the second scanning plane that is orthogonal to the first scanning plane. In FIG. 5 and FIG. 6 to be described later, vector symbols are added for vector information. However, in the following description, vector symbols are omitted for vector information.

By the above-described inter-frame correlation calculation, a two-dimensional vector representing the movement of the point of interest (the point of interest O set on the intersection line of the two scanning planes) is calculated for each scanning plane. For the first scanning plane A, parallel motion components (d _Ax , d _Ay ) between frames are obtained, and similarly, for the second scanning plane B, parallel motion components (d _By , d _Bz ) between frames are obtained. Desired. That is, two two-dimensional vectors are calculated. d _Ay and d _By have the same value in principle, but may actually be different values. Therefore, in calculating the three-dimensional vector d _M constituting the three-dimensional motion information, one of the two is selected. It is desirable to use it selectively or to use the average value of both. In FIG. 5, T ₀ and T ₁ indicate position vectors of the attention points O and O ′ before and after the movement.

  FIG. 6 conceptually shows a method for calculating three-dimensional rotational motion information as three-dimensional motion information. The amount of rotation between frames (rotation vector) determined for the first scanning plane A is α, and similarly, the amount of rotation between frames determined for the second scanning plane B (rotation vector) is β. A combined vector of these rotation amounts is represented as γ.

  As described above, since parallel motion information and rotational motion information are obtained as three-dimensional motion information between individual frames, scanning plane data for image formation (tomographic images) that are sequentially captured or sequentially captured using the information. It is possible to specify the spatial coordinates of the data. That is, the coordinates of individual echo data (voxel data) in the three-dimensional storage space can be specified by image processing. The above three-dimensional motion information is acquired in chronological order for each frame, and the position and rotation angle of the point of interest in the absolute space can be obtained from their synthesis or integration. Here, the scan surface data for image formation is the first scan surface data or the second scan surface data in the present embodiment. However, it is also possible to construct volume data using both of them. Alternatively, as described above, the third scan plane data may be acquired to construct volume data. If the positional relationship of the third scan plane with respect to the first scan plane and the second scan plane is known, the position of the third scan plane can be easily specified from the positions of the first scan plane and the second scan plane.

  Next, various manual scanning modes will be described with reference to FIGS. In FIG. 7, U schematically represents a volume space. A first scanning plane A and a second scanning plane B exist so as to cross the volume space. When the probe is moved by manual scanning by the user, the scanning planes A and B move in the lateral direction of the paper as indicated by U '. Since each scanning surface is repeatedly electronically formed, if attention is paid to the first scanning surface A here, in the process of manual scanning, a plurality of first scanning surfaces are formed in alignment with the manual scanning direction. become. A scanning plane array configured as such is indicated by reference numeral 70, and an element as a scanning plane constituting the scanning plane array is indicated by reference numeral 72.

  In the example shown in FIG. 8, the probe, that is, the volume space U moves in the direction perpendicular to the paper surface. In this case, the scanning plane row 70 as described above is formed as a result of the second scanning plane B moving in the vertical direction. As described above, it is desirable to select a scanning plane used in image formation in accordance with the manual scanning direction of the probe. In this case, it is desirable to determine a scanning plane orthogonal to the moving scanning direction as much as possible as a scanning plane for image formation. Of course, the other scanning plane is also formed sequentially, and the above-described three-dimensional motion information is calculated based on the data obtained by forming the two scanning planes.

  In the example shown in FIG. 9, in addition to the first scanning surface A and the second scanning surface B, a third scanning surface C is formed. This third scanning plane C is a scanning plane dedicated for image formation. That is, a scanning surface for measuring three-dimensional motion information may be distinguished from a scanning surface for image formation. For example, the beam density may be coarse for the former and the beam density may be dense for the latter. Further, parameters other than the beam density, that is, the scanning width and the scanning depth may be varied.

  In the example shown in FIG. 10, the probe, that is, the volume space U moves in an oblique direction on the paper surface. Even in such a case, it is possible to configure volume data while accurately specifying the spatial coordinates of each data using data on any of the scanning planes.

  The example shown in FIG. 11 shows an example in which the probe moves in parallel and rotates. Even in such a case, the position of each scanning plane can be accurately specified, so that volume data can be accurately reconstructed.

  In the example shown in FIG. 12, in the manual scanning of the probe, ie, the volume space, a plurality of motion components (including rotational motion components) are generated in addition to the motion components in the main manual scanning direction. Since the surface of the living body is not flat, there is a high possibility that such a state will occur. Incidentally, in FIG. 12, A 'and B' indicate the first scanning surface and the second scanning surface after movement. L indicates a reference axis before movement, and L ′ indicates a reference axis after movement. Even in such a case, in this embodiment, rotational motion information can be calculated in addition to parallel motion information as three-dimensional motion information, so that the position of each scanning plane can be accurately identified and volume data can be constructed. It is.

  FIG. 13 conceptually shows a volume data construction method. (A) shows a frame data string 70. As described above, the frame data string 70 is constituted by the tomographic image data 72 acquired at each timing of manual scanning. Although the frame data string 70 shown in FIG. 4A is apparently aligned spatially, in reality, they are spatially uneven due to the influence of hand shake and respiratory motion. As shown in (B), according to the present embodiment, three-dimensional motion information can be obtained for each frame, that is, for each tomography, so that each tomographic image data is stored in the storage space 76 using this information. If mapping is performed, appropriate volume data 74 can be obtained. Here, reference numeral 72A indicates tomographic image data after coordinate conversion, that is, after mapping. By the way, when the volume data 74 is constructed on the memory, the maximum coordinate that protrudes most in each coordinate axis direction is specified for the frame data sequence, and it is effective with the rectangular parallelepiped shape specified by the three maximum coordinates obtained for the three axes. A storage space may be used. For example, it is desirable to apply the above processing in order to make maximum use of the memory space when zooming when writing to the memory, and the above processing is also used when performing interpolation processing. Thus, the spatial region where the data actually exists may be specified in advance.

  (B) Use of a thick scanning plane

  In the embodiment described above, it is desirable to configure each scanning surface as a thick scanning surface in order to properly continue the correlation processing for each of the two scanning surfaces. That is, even if the probe or the target tissue moves in a direction orthogonal to the scanning plane, the correlation processing is prevented from being interrupted. The thick scan plane is a scan plane that is increased in the thickness direction as compared with a normal thin scan plane employed in an operation mode such as a normal B mode. FIG. 14 shows a comparative example, in which thin scanning planes A1 and B1 configured by scanning two thin beams 100 and 102 in the electronic scanning directions 101 and 103 (cross scanning) are shown. . FIG. 15 shows thick scanning planes A2 and B2 configured by scanning (cross scanning) two thick beams 104 and 106 in the electronic scanning directions 105 and 107. By forming such a thick biplane, even if the probe and the target tissue move in an arbitrary direction, the movement can be accurately tracked, that is, each correlation process can be performed appropriately.

  An ultrasonic image can be formed using one or both of the two scanning planes shown in FIG. However, if a thick scanning surface is used, the spatial resolution is lowered, so that a third scanning surface may be formed. An example of the configuration is shown in FIG. In this example, in addition to the thick scanning surfaces A2 and B2, a thin scanning surface C that crosses them is repeatedly formed. Reference numeral 112 denotes a scan plane sequence, which corresponds to a scan plane data sequence. Reference numeral 112A indicates individual scanning planes constituting the scanning plane array.

  FIG. 17 shows a generation principle for a thick beam formed when a thick scanning plane is generated. In this example, two types of areas are drawn on the two-dimensional array transducer 112, the area 114 is a circular area, and the area 116 is an elliptical area. Reference numeral 118 denotes a weighting function in the first scanning direction, and reference numeral 120 denotes a weighting function in the second scanning direction. These functions generally correspond to areas 114 and 116. The weighting functions 118 and 120 are functions different from each other. The former has a sharp overall shape that is narrow from the center (width at half maximum), and the latter has a broad overall shape that is wide from the center. By adopting a two-dimensional weight function in this way, it is possible to form an ultrasonic beam (transmission beam, reception beam) having a flat cross section. In this example, it is possible to form an ultrasonic beam having a configuration in which the beam size in the second scanning direction (vertical direction on the paper surface) is smaller than the beam size in the first scanning direction (horizontal direction on the paper surface). That is, such an ultrasonic beam is electronically scanned in the second scanning direction, and a scanning surface is formed in that direction. The thickness direction is the first scanning direction. Although it is possible to use a thick ultrasonic beam having a circular cross section, the spatial resolution in the scanning plane direction can be improved by forming an ultrasonic beam having a flat cross section as described above.

  As already described, if a thick scanning plane is repeatedly formed, correlation processing can be performed properly even if the probe or the tissue of interest moves in various directions. In particular, in the above embodiment, since the motion is measured from two directions using the biplane, the motion estimation accuracy can be further improved and the reliability of the motion measurement can be increased.

1 is a block diagram showing an embodiment of an ultrasonic diagnostic apparatus according to the present invention. It is a figure which shows two scanning surfaces orthogonal to each other. It is a figure which shows the parallel movement vector calculated | required between frames. It is a figure which shows the rotational motion vector calculated | required between frames. It is a figure which shows the calculation method of a parallel motion vector. It is a figure which shows the calculation method of a rotational motion vector. It is a figure which shows the 1st example about the manual scanning of a probe. It is a figure which shows the 2nd example about the manual scan of a probe. It is a figure which shows the 3rd example about the manual scan of a probe. It is a figure which shows the 4th example about the manual scan of a probe. It is a figure which shows the 5th example about the manual scan of a probe. It is a figure which shows the 6th example about the manual scan of a probe. It is explanatory drawing which shows the method of constructing | assembling volume data from a frame data sequence. It is explanatory drawing which shows two thin scanning surfaces. It is explanatory drawing which shows two thick scanning surfaces. It is explanatory drawing which shows two thick scanning surfaces and the scanning surface for image formation. It is a figure which shows the production | generation principle about a thick beam.

Explanation of symbols

  10 probe, 15 probe motion measurement unit, 16 coordinate conversion unit, 18, 20 correlation unit, 22 vector calculation unit, 28 spatial arrangement unit.

Claims (4)

A wave transmission / reception unit that repeatedly forms a scanning surface by ultrasonic wave transmission / reception;
Correlation processing means for performing correlation processing between temporally different scan plane data obtained by transmission and reception of the ultrasonic waves to obtain a correlation processing result;
A means for controlling the formation of the scanning surface, wherein in the first operation mode, a thin scanning surface is repeatedly formed by an ultrasonic beam having a thin beam shape, and the correlation process is executed. Then, a control means for repeatedly forming at least one thick scanning plane by an ultrasonic beam having a thick beam shape,
Including
The ultrasonic diagnostic apparatus according to claim 1, wherein the beam size in the direction perpendicular to the beam scanning direction is larger than the beam size in the beam scanning direction in the ultrasonic beam having the thick beam shape. A wave transmission / reception unit that repeatedly forms a scanning surface by ultrasonic wave transmission / reception;
Correlation processing means for performing correlation processing between temporally different scan plane data obtained by transmission and reception of the ultrasonic waves to obtain a correlation processing result;
A means for controlling the formation of the scanning surface, wherein in the first operation mode, a thin scanning surface is repeatedly formed by an ultrasonic beam having a thin beam shape, and the correlation process is executed. Then, a control means for repeatedly forming at least one thick scanning plane by an ultrasonic beam having a thick beam shape,
Including
In the second operation mode, the first scanning surface and the second scanning surface intersecting each other are repeatedly formed,
The ultrasonic diagnostic apparatus, wherein both the first scanning plane and the second scanning plane are the thick scanning plane. The apparatus of claim 2 .
In the second operation mode, a third scanning plane different from the first scanning plane and the second scanning plane is further repeatedly formed,
The ultrasonic diagnostic apparatus, wherein the third scanning plane is a thin scanning plane. A wave transmission / reception unit that repeatedly forms a scanning surface by ultrasonic wave transmission / reception;
Correlation processing means for performing correlation processing between temporally different scan plane data obtained by transmission and reception of the ultrasonic waves to obtain a correlation processing result;
A means for controlling the formation of the scanning surface, wherein in the first operation mode, a thin scanning surface is repeatedly formed by an ultrasonic beam having a thin beam shape, and the correlation process is executed. Then, a control means for repeatedly forming at least one thick scanning plane by an ultrasonic beam having a thick beam shape,
Including
The transmission / reception unit includes a 2D array transducer,
When an ultrasonic beam having the thick beam shape is formed, a wide weighting characteristic is set in the first direction and a narrow weighting characteristic is set in the second direction on the 2D array transducer. An ultrasonic diagnostic apparatus.

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