JP2005095278A - Ultrasonograph - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable a three-dimensional angle correction of a blood flow velocity and to reduce a burden for a user of a necessary setting work for the same in an ultrasonograph. <P>SOLUTION: A sample gate central position is appointed by the user using three sections which intersect at right angles to the inside of the three-dimensional space. An arbitrary section is set by the user as a plane including the sample gate central position. In that case, an actual direction of the blood flow (a blood flow vector) is set to be included in the arbitrary section. Then, the actual direction of the blood flow is appointed by the user on the arbitrary section. The correction angle is acquired from the information of coordinates of the arbitrary section and the angle of the direction of the blood flow, thereby the three-dimensional angle correction of the blood flow velocity is performed. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an ultrasonic diagnostic apparatus, and more particularly to angle correction of Doppler information.

  Recently, various methods for constructing a three-dimensional image from three-dimensional ultrasonic data (echo data, Doppler data) obtained from a three-dimensional space of a living body have been proposed. As such a technique, a volume rendering method based on a light transmission / scattering model is known (see, for example, Patent Document 1). Various volume rendering methods are also known. Furthermore, there are methods for rendering information in a three-dimensional space on a two-dimensional plane, such as a method for performing simple integration along a ray (line of sight), a method for searching for a maximum value along the ray, and other projection methods. In addition, a surface method or the like is known for three-dimensional image formation.

  By the way, the following patent document 2 discloses a concept of setting a sample gate (sample volume) in a three-dimensional space, performing frequency analysis on Doppler information obtained therefrom, and forming a Doppler waveform as a result. This applies normal Doppler processing to Doppler information in a three-dimensional space.

Japanese Patent No. 2883584 JP 2001-190552 A

  It is known that the blood flow velocity observed as Doppler information in the sample gate is actually a velocity component along the ultrasonic beam direction. Therefore, in a conventional apparatus that displays a two-dimensional tomographic image, the blood flow direction is corrected on the basis of the blood flow direction after the blood flow direction is designated by the user on the tomographic image. A function of displaying a Doppler waveform is provided. However, even in the case of such speed correction, it is only speed correction on the scanning plane corresponding to the tomographic image, and does not determine the true blood flow speed. Note that the apparatus described in Patent Document 1 does not include a configuration for performing speed correction.

  An object of the present invention is to make it possible to calculate an accurate blood flow velocity.

  Another object of the present invention is to enable a user to easily and accurately specify a blood flow direction in a three-dimensional space when correcting a blood flow velocity.

  The present invention provides an ultrasonic diagnostic apparatus that sets a sample gate in a three-dimensional space in which ultrasonic waves are transmitted and received, and calculates a blood flow velocity based on Doppler information obtained from the sample gate. The three-dimensional blood flow direction setting means for setting the three-dimensional blood flow direction in relation to the three-dimensional blood flow direction, and the three-dimensional angle correction based on the cross relationship between the direction of the Doppler beam passing through the sample gate and the three-dimensional blood flow direction And a three-dimensional angle correction means for calculating the blood flow velocity.

  According to the above configuration, when the three-dimensional blood flow direction is set by the user or automatically, the blood flow velocity with angle correction is calculated based on the cross relationship between the three-dimensional blood flow direction and the Doppler beam direction. Is done. Therefore, since the three-dimensional angle correction can be performed on the blood flow velocity in accordance with the actual blood flow direction, the blood flow velocity can be accurately obtained.

  In the above configuration, the sample gate is generally set with a certain size on the Doppler beam. The Doppler information is information representing the blood flow, and the blood flow velocity or velocity distribution is calculated by frequency analysis of the Doppler information.

  In setting the three-dimensional blood flow direction, the flow direction and the positive or negative direction in that direction may be specified, and the flow direction is not specified as in the case of two-dimensional angle correction. It is also possible to specify only the direction regardless of positive or negative. For example, in the former case, the three-dimensional blood flow direction is represented by a vector, and in the latter case, the three-dimensional blood flow direction is represented by a simple line. Preferably, the origin, end point, or center point of the vector or line coincides with the reference point (center point, etc.) of the sample gate.

  The three-dimensional blood flow direction may be set directly on the three-dimensional space, or may be indirectly set by specifying the two-dimensional blood flow direction on an arbitrary tomographic image, as will be described later. The three-dimensional angle correction is normally performed on the blood flow velocity after the blood flow velocity is calculated based on the Doppler information, but may be performed on the Doppler information before the blood flow velocity is calculated. .

  Desirably, for the three-dimensional space, an arbitrary cross section setting means for setting an arbitrary cross section in relation to the sample gate, and an arbitrary tomographic image forming means for forming an arbitrary tomographic image corresponding to the arbitrary cross section The three-dimensional blood flow direction setting means designates the two-dimensional blood flow direction on the arbitrary cross section by causing the user to set the direction of the two-dimensional blood flow marker displayed on the arbitrary tomographic image. And means for calculating the three-dimensional blood flow direction based on the coordinate information about the arbitrary cross section and the two-dimensional blood flow direction.

  According to the above configuration, first, a two-dimensional plane including a two-dimensional blood flow direction is determined by setting an arbitrary cutting plane, and then a two-dimensional blood flow direction is set on the two-dimensional plane. In this way, the direction of blood flow can be specified after reducing the number of dimensions by setting the surface, so that the three-dimensional blood flow direction can be set quickly and accurately.

  Preferably, the arbitrary tomographic image is a two-dimensional tissue blood flow image in which tissue and blood flow are represented. According to this configuration, an arbitrary cross section and a blood flow direction can be set while observing blood flow in addition to tissue.

  Preferably, the apparatus includes a three-dimensional storage unit that stores tissue data and blood flow data acquired in the three-dimensional space, and the arbitrary tomographic image forming unit includes a tissue corresponding to the arbitrary cross section from the three-dimensional storage unit. Means for reading out data to form a black and white tissue tomographic image; means for reading out blood flow data corresponding to the arbitrary cross section from the three-dimensional storage means to form a color blood flow tomographic image; and the tissue tomographic image; Means for combining the blood flow tomographic image and forming a color flow mapping image as the two-dimensional tissue blood flow image.

  Preferably, the blood flow tomographic image is an image representing high-speed blood flow of a certain speed or higher. According to this configuration, even when turbulence occurs, the main part or the center part of the flow can be easily recognized, and the setting of the two-dimensional blood flow direction is facilitated.

  Preferably, the three-dimensional angle correction means calculates an angle formed by the Doppler beam azimuth and the three-dimensional blood flow direction, and executes the three-dimensional angle correction based on the angle.

  Preferably, means for setting a plurality of cross sections orthogonal to each other with respect to the three-dimensional space, means for forming a plurality of tomographic images corresponding to the plurality of cross sections, and cross coordinates of the plurality of cross sections. And a means for setting the Doppler beam direction as a direction connecting the reference point of the sample gate and the ultrasonic wave transmission / reception origin.

  According to the above configuration, the reference point (for example, the center point) of the sample gate can be set by setting a plurality of cross sections orthogonal to each other, which is convenient. In other words, since each cross-section independently translates on the three-dimensional coordinate axis, its operation and setting are easy, and the spatial grasp of the tissue from multiple tomographic images that are orthogonal to each other at the time of setting each cross-section Is also easy. Even in a mode in which angle correction is not performed, the above-described configuration can be employed in setting the sample gate.

  As described above, according to the present invention, an accurate blood flow velocity can be calculated. Further, according to the present invention, by setting the blood flow direction using an arbitrary tomographic image, the user can easily and accurately specify the blood flow direction in the three-dimensional space when performing the blood flow velocity correction calculation.

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

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

  The 3D probe 10 is used, for example, in contact with the body surface. In the present embodiment, the 3D probe 10 has a 2D array transducer. The 2D array transducer is formed by two-dimensionally arranging a plurality of transducer elements. An ultrasonic beam is formed by the 2D array transducer, and the ultrasonic beam is scanned two-dimensionally. As a result, a three-dimensional data capture space (three-dimensional space) is formed. Examples of the electronic scanning method include electronic sector scanning.

  The transmission / reception unit 12 functions as a transmission beam former and a reception beam former. That is, a transmission beam is formed by supplying a plurality of transmission signals with a fixed delay relationship to a plurality of vibration elements, and A / D is applied to a plurality of reception signals output from the plurality of vibration elements. By executing the conversion process and the phasing addition process, a reception beam is formed electronically.

  In this embodiment, in order to acquire both echo data (tissue luminance information) and Doppler data (blood flow information) in a three-dimensional space, transmission and reception of ultrasonic waves for acquiring echo data for each beam direction. Waves and ultrasonic waves for acquiring Doppler data are transmitted and received. Of course, both echo data and Doppler data may be obtained simultaneously by transmitting and receiving the same ultrasonic wave. In this embodiment, in order to form a Doppler waveform according to the ultrasonic pulse Doppler method, an ultrasonic beam (Doppler beam) for Doppler observation is repeatedly formed intermittently in a specific direction set by the user. It also has a function. Such a transmission / reception sequence is set by a control unit 52 described later, that is, the transmission / reception unit 12 performs its operation under the control of the control unit 52. The transmission / reception sequence can be appropriately set according to the diagnostic application and purpose.

  A tissue image formation reception signal (tissue data) output from the transmission / reception unit 12 is stored in the tissue 3D memory 16 via the processor 14. The processor 14 has functions such as detection, logarithmic compression, and coordinate conversion. Of course, data that is not subjected to such processing may be stored in the organization 3D memory 16.

  The tissue 3D memory 16 has a storage space corresponding to a three-dimensional space as a transmission / reception space. The address of the tissue 3D memory 16 is associated with coordinates in a three-dimensional space. The processor 18 is a module that performs necessary data processing before performing a composition operation on the tissue data read from the tissue 3D memory 16. The processors 14 and 18 are provided as necessary.

  A blood flow image forming reception signal (blood flow data including Doppler information) output from the transmission / reception unit 12 is stored in the blood flow 3D memory 22 via the processor 20. For example, when a blood flow image is formed using a known autocorrelation method or the like, the processor 20 performs signal processing such as quadrature detection, wall motion removal processing, and autocorrelation calculation. Thereby, the blood flow 3D memory 22 stores blood flow average velocity data as blood flow data.

  Similar to the tissue 3D memory 16 described above, the blood flow 3D memory 22 has a storage space corresponding to a three-dimensional space in the living body, and an address thereof is associated with a coordinate in the three-dimensional space.

  The blood flow data read from the blood flow 3D memory 22 is output via the processor 24 to the synthesis calculation unit 26 that executes the synthesis calculation. The processor 24 is a module that performs necessary data processing before performing the synthesis operation on the blood flow data read from the blood flow 3D memory 22, and is provided as necessary. For example, when the tissue is expressed in black and white, the blood flow is expressed in color, and they are combined and displayed, the processor 18 and the processor 24 each have a color coding function. On the other hand, processing for assigning R, G, and B luminances equally to the data is executed. On the other hand, the processor 24 assigns hues (for example, R, B) according to the direction of blood flow and assigns the luminances of the respective colors to blood. A process corresponding to the magnitude of the flow velocity is executed. Of course, such color coding processing is an example, and various coloring conditions can be adopted as long as the tissue and blood flow can be easily recognized as a three-dimensional image.

  On the other hand, the graphic generation unit 28 generates three-dimensional graphic data, graphic images, and the like according to the graphic creation parameters passed from the control unit 52. Here, the generated three-dimensional graphic data is stored in the 3D memory 30, and the 3D memory 30 has the same storage space as the tissue 3D memory 16 and the blood flow 3D memory 22 described above. The address of the 3D memory 30 is associated with the coordinates in the three-dimensional space.

  In the present embodiment, the three-dimensional graphic data is configured as color data, that is, each data element is configured by R data, B data, and G data. Of course, it is also possible to use simple luminance data as graphic data.

  In the composition calculation unit 26, composition calculation of tissue data, blood flow data (blood flow velocity data), and graphic data is executed for each coordinate in the three-dimensional space. In this case, in order to realize the color combination processing, it is desirable that the combination calculation is performed for each of R, G, and B colors. In addition, it is desirable to perform constant weighting on the tissue data and the blood flow data so that the blood flow is naturally expressed with a sense of perspective in the tissue and the tissue existing behind the blood flow is transparently expressed. . According to such processing, for example, it is possible to display the heart wall in the heart and express the blood flow existing in the heart with a transparent feeling. Further, graphic data is combined with those data. For example, a graphic representing a sample gate, a line representing a Doppler orientation, and the like are combined as graphic elements. As a result, in a 3D image generated by rendering described later, one or more graphic elements are spatially expressed with a sense of perspective, along with tissue and blood flow.

  The composite data obtained for each coordinate as a result of the composite operation as described above is stored in the 3D memory 32. The 3D memory 32 has a storage space similar to that of the 3D memories 16, 22, and 30 described above, and addresses thereof are associated with coordinates in a three-dimensional space.

  In the rendering unit 34, the rendering process is executed on the data that has been subjected to the above three-dimensional synthesis process. Specifically, for each ray set in the three-dimensional space, for each synthetic data existing on that ray, for example, a voxel operation based on the volume rendering method is developed, and as a result, a pixel value for each ray. Seeking. In this case, in order to perform color rendering, the rendering unit 34 performs rendering processing for each of R, G, and B. That is, as is clear from the above description, as a result of the synthesis operation, synthesized data is stored for each of R, G, and B for each coordinate on the 3D memory 32, that is, such data The set is stored at each address on the 3D memory 32. Then, when the data set is read, each composite data constituting the data set is subjected to rendering processing for each color of R, G, and B.

  The pixel values calculated by the rendering unit 34, that is, R data, G data, and B data are sent to the display processing unit 36, and the frame memory provided on the display processing unit 36 has a three-dimensional space in two dimensions. A color 3D display image projected onto the plane is constructed.

  By the way, when ultrasonic waves are repeatedly transmitted and received in a specific Doppler beam direction according to the ultrasonic pulse Doppler method, a reception signal obtained thereby is output to the gate circuit 42. The gate circuit 42 extracts a partial signal corresponding to the sample gate (sample volume) set on the Doppler beam azimuth and outputs it to the Doppler calculation unit 44. The Doppler calculation unit 44 includes a quadrature detection circuit, a frequency analysis circuit (FFT analyzer), and the like, so that Doppler information (Doppler shift frequency component) is extracted from the input signal, and the Doppler information is on the frequency axis. Expanded to Thereby, a speed spectrum composed of power for each frequency (speed) is obtained as a frequency analysis result. The blood flow velocity information representing it is output to the angle correction unit 46.

  Although a specific processing method of the angle correction unit 46 will be described in detail later, in this embodiment, the angle correction unit 46 has a three-dimensional angle correction function, and the blood flow velocity obtained on the Doppler beam. The true blood flow velocity is calculated by performing three-dimensional angle correction on the. That is, when a velocity spectrum as blood flow velocity information is obtained in the Doppler calculation unit 44, the magnitude (amplitude) of the velocity spectrum is corrected, or the vertical scale thereof is corrected.

  The Doppler waveform forming unit 48 forms a Doppler waveform based on the blood flow velocity information after the three-dimensional angle correction. As is well known, the horizontal axis of the Doppler waveform is the time axis, and the vertical axis corresponds to the blood flow velocity. Further, the luminance of each pixel in the waveform is associated with the magnitude of power at each speed. Image data representing the Doppler waveform is output to the display processing unit 36.

  On the other hand, the arbitrary CFM (color flow mapping) image processing unit 38 has a function of forming a two-dimensional black and white tissue image, a function of forming a two-dimensional color blood flow image, and a CFM image by combining these images. And a function to form. In this case, tissue data and blood flow data for forming the image are acquired from an arbitrary cross section arbitrarily set by the user with respect to the three-dimensional space. Specifically, when coordinate information of an arbitrary cross section is passed from the control unit 52 to the arbitrary CFM image processing unit 38, the arbitrary CFM image processing unit 38 reads tissue data corresponding to the arbitrary cross section from the tissue 3D memory 16. In addition, blood flow data corresponding to the arbitrary cross section is read from the blood flow 3D memory 22. Then, as described above, a two-dimensional black and white tissue image and a two-dimensional color blood flow image are formed in accordance with the data, and an arbitrary CFM image is generated by synthesizing them. The image data is output to the display processing unit 36.

  The multi-CFM image processing unit 40 has a function of forming three CFM images corresponding to three cross sections corresponding to a triplane set by a user. That is, like the arbitrary CFM image processing unit 38, the multi-CFM image processing unit 40 has a function of forming a two-dimensional monochrome tissue image, a function of forming a two-dimensional color blood flow image, And a function of synthesizing images to form a CFM image. In particular, since three CFM images corresponding to three orthogonal cross sections are formed and displayed, it is easy to grasp the tissue spatially.

  When the coordinate information of each cross section is passed from the control unit 52 to the multi-CFM image processing unit 40, the multi-CFM image processing unit 40 reads the tissue data corresponding to each cross-section from the tissue 3D memory 16, and similarly to this. The blood flow data corresponding to each cross section is read from the blood flow 3D memory 22. Then, three CFM images are formed as described above, and the respective image data are output to the display processing unit 36.

  In the present embodiment, an identification processing unit 41 is provided between the blood flow 3D memory 22 and the arbitrary CFM image processing unit 38 and the multi-CFM image processing unit 40. The identification processing unit 41 has a function of extracting only blood flow data corresponding to blood flow at a certain speed (threshold value) or more from input blood flow data, that is, blood flow corresponding to high-speed blood flow. Only data can be passed to the arbitrary CFM image processing unit 38 and the multi-CFM image processing unit 40. According to this configuration, when a color blood flow image is formed in the arbitrary CFM image processing unit 38, only high-speed blood flow is expressed in the image. Therefore, when an arbitrary CFM image is observed, high-speed blood flow can be easily recognized in relation to the tissue, so that the user can easily specify the direction of blood flow on the arbitrary CFM image. Also, in each CFM image constituting the multi-CFM image, only the high-speed blood flow is expressed, so that the setting of the sample gate is facilitated. Of course, when forming each CFM image, the whole blood flow data may be imaged. Alternatively, the high-speed blood flow may be identified and expressed by a technique such as a process for increasing the brightness of the high-speed blood flow or a process for applying special coloring to the high-speed blood flow.

  The graphic image generated by the graphic generation unit 28 is supplied to the display processing unit 36, and the display processing unit 36 performs necessary graphics for the 3D display image, arbitrary CFM image, multi-CFM image, and Doppler waveform. Data is overlaid, thereby forming a display image. The image data is output to the display unit 50, and one or a plurality of images are displayed side by side in a display form according to the display mode. The display unit 50 may be configured by a plurality of display devices.

  The control unit 52 performs operation control of each configuration illustrated in FIG. 1, and an operation panel 54 is output to the control unit 52. The operation panel 54 includes a trackball and a keyboard, and the user can designate coordinates of three cross sections corresponding to the multi-CFM image, and can also specify coordinates of an arbitrary cross section corresponding to the arbitrary CFM image. (Especially posture) can be specified. In this embodiment, as will be described later, by appropriately adjusting the positions of the three cross sections corresponding to the triplane, the cross relationship between the three cross sections, specifically, the sample gate center as the coordinates of the cross points. A position is specified. When such a sample gate center position is set, under the control of the control unit 52, the transmission / reception unit 12 sets the Doppler beam direction as an azimuth passing through the sample gate center point.

  Further, as will be described later, an arbitrary cross section can be freely set by the user as a plane including the sample gate center point. In this embodiment, the actual blood is observed while observing an arbitrary CFM image. The three-dimensional position and posture of the arbitrary cross section can be set by the user so that the flow direction is included in the arbitrary cross section. Once an arbitrary cross section is set, the actual blood flow direction is designated by the user using a marker or the like on the corresponding arbitrary CFM image in relation to the image content. When such an actual blood flow direction is designated, a correction angle necessary for three-dimensional angle correction is automatically calculated from the coordinate information of the arbitrary cross section and the blood flow direction on the arbitrary cross section. The correction angle corresponds to an angle formed by the Doppler beam azimuth and the actual blood flow direction.

  A three-dimensional space 60 is shown in FIG. When the ultrasonic beam formed by the 3D probe 10 is two-dimensionally scanned by an electronic sector, a three-dimensional space 60 having a pyramid shape as shown in FIG. 2 can be formed. In the example shown in FIG. 2, a display target space 62 is set inside the three-dimensional space, and when data is actually stored in the 3D memory, only data corresponding to the display target space 62 is stored in the 3D memory. Stored in However, data may be stored in the 3D memory for the entire three-dimensional space 60.

  In the example illustrated in FIG. 2, the heart is a diagnosis target, and the intimal surface 64 of the heart is represented. A valve 66 is present on the inner membrane surface 64, and the valve 66 has an opening 68. In the case of diagnosing the function of the valve 66, the blood flow passing through the valve is diagnosed according to the ultrasonic Doppler method. In this case, a Doppler beam as indicated by reference numeral 70 is formed. The That is, for example, an ultrasonic beam that passes through the opening 68 and forms a focus in the vicinity thereof is repeatedly formed. Reference numeral 72 denotes the Doppler gate center position, which is not shown in FIG. 2, but a sample gate having a predetermined gate length width in the Doppler beam azimuth with the Doppler gate center position 72 as the center or reference is set. In this case, the sample gate length can be variably set by the user.

  FIG. 3 shows a combination display example of a multi-CFM image and a 3D display image. That is, three CFM images 74, 76, 78 and one 3D display image 80 are simultaneously displayed on the screen of the display unit 50, and it is possible to comprehensively observe the tissue structure and the state of blood flow using them. In addition, the sample gate center position can be set while observing the three CFM images 74, 76, 78 and the like.

  In the example illustrated in FIG. 3, the multi-CFM image includes a CFM image 74 viewed from above, a CFM image 76 viewed from the side, and a CFM image 78 viewed from the front. Incidentally, the cross section corresponding to each image is orthogonal in the three-dimensional space, and such a display form is called a triplane display. Each CFM image 74, 76, 78 represents a sample gate center position 82 as a marker, and an auxiliary line 84 that passes through the sample gate center position 82 is shown. Such an auxiliary line 84 specifies the three-dimensional coordinates of the sample gate center position 82 and at the same time represents the crossing position of another section viewed from one section.

  The 3D display image 80 is formed by the rendering process described above, and in the example illustrated in FIG. 3, the tissue is represented. However, as described above, the blood flow may be expressed in color simultaneously with the tissue. .

  The 3D display image 80 has an image portion 80A corresponding to a tissue (or blood flow) and a portion 80B corresponding to a graphic. In this example, as conceptually shown in FIG. 2, the structure near the heart valve is represented. Further, a gate marker 96 representing a sample gate in relation to the valve opening is represented by a cylindrical figure, and an orientation marker 98 representing a Doppler beam direction is represented as a line. In addition to the gate marker 96, a marker 100 representing the center value is shown.

  Reference numeral 90 is a marker representing a plane corresponding to the CFM image 74 viewed from above, reference numeral 92 is a marker representing a plane corresponding to the CFM image viewed from the side, and reference numeral 94 is a CFM viewed from the front. This is a marker representing a plane corresponding to the image 78. In addition, auxiliary lines 102 representing the intersections of the planes are drawn, and such auxiliary lines 102 also represent the three-dimensional coordinates of the center position 100 of the sample gate.

  For example, in the stage of setting the sample gate as a premise that the ultrasonic Doppler method is applied, the triplane + 3D display mode as shown in FIG. 3 is adopted, and the position of each cross section constituting the triplane is set by the user on each axis. By shifting upward, the center position of the sample gate can be set quickly and easily. It is also possible to observe the set state as a 3D display image 80.

  By the way, in this embodiment, since the rendering process is executed after the composition operation is performed, each graphic element can be expressed spatially without a sense of incongruity in relation to the organization. There is an advantage that it can be observed.

  When the setting of the position of each cross section constituting the triplane is completed, the sample gate center position is automatically recognized as the intersection of the cross sections, and the Doppler beam azimuth is automatically set as the direction passing through the sample gate center position. The Then, ultrasonic waves are repeatedly transmitted and received in accordance with a fixed transmission / reception sequence with respect to the Doppler beam direction.

  In this case, according to the gate length set by the user or set as a default, the sample gate is set with reference to the center position of the sample gate, and Doppler information in the sample gate is observed. At this time, when performing three-dimensional angle correction, a process of directly or indirectly designating a three-dimensional blood flow direction by a user using a display mode described below is executed.

  FIG. 4 shows a combination display example of the arbitrary CFM image 110, the 3D display image 80 shown in FIG. 3, and the Doppler waveform 122. In other words, such three images are combined and displayed on the display screen of the display unit 50 at the same time.

  The arbitrary CFM image 110 is an image obtained by synthesizing the two-dimensional tissue image and the two-dimensional blood flow image formed based on the tissue data and the blood flow data obtained from the arbitrary cut surface as described above. In the form, only high-speed blood flow is expressed in color. Reference numeral 112 represents a cross section of the tissue near the valve, and reference numeral 114 represents high-speed blood flow. Actually, the high-speed blood flow is expressed according to predetermined color coding conditions.

  Reference numeral 116 is a marker indicating the center position of the sample gate, and auxiliary lines 118 are shown in the vertical and horizontal directions so as to pass through the marker 116.

  While observing the arbitrary CFM image 110, the user can freely set the position of the arbitrary cross section by using the operation panel 54. In such a process, the actual blood flow is displayed on the CFM image. The angle of the arbitrary cross section is appropriately adjusted so that the direction is included.

  Then, when an arbitrary cross section is set in a desired posture, a correction marker (correction line) 120 appears on the arbitrary CFM image 110 as a line or an arrow, and an operation for adjusting the direction of the marker to the blood flow direction is performed. . By such an action, on the apparatus side, it is possible to obtain angle information for performing three-dimensional angle correction, as will be described in detail later, from the coordinate information of the arbitrary cutting plane and the rotation angle of the marker.

  The contents of the 3D display image 80 are also changed in real time during the display and operation of the arbitrary CFM image 110 as described above. In this mode, the three-dimensional display image 80 includes a marker 104 representing a plane corresponding to an arbitrary cross section. A gate marker 96 and an orientation marker 98 are also displayed, and auxiliary lines 106 and 108 are also displayed. These auxiliary lines are orthogonal lines whose intersection is the marker 100 indicating the sample gate center position.

  When the three-dimensional angle correction is performed by the above operation, the scale of the vertical axis on the Doppler waveform 122 is correctly displayed, that is, the blood flow velocity can be accurately observed.

  By the way, at the stage where the center position of the sample gate is set, the triplane display and 3D display image are formed based only on the tissue data, and subsequently the actual blood flow direction is designated using an arbitrary CFM image. When performing, the transmission and reception for acquiring Doppler information may be performed together to form the display mode as shown in FIG. Further, when observing the Doppler waveform, the image formed so far may be frozen, and the Doppler waveform may be formed by repeatedly transmitting and receiving ultrasonic waves in the Doppler beam direction.

  Furthermore, a large-capacity storage device is provided as the tissue 3D memory 16 and the blood flow 3D memory 22, and all the data over a certain period of time are stored therein, and the various images described above based on the data read from the storage device. May be formed. The Doppler waveform may be observed after necessary settings are completed based on the stored data.

  FIG. 4 is a flowchart showing the main steps in the operation of the apparatus shown in FIG.

  In S101, the center position of the sample gate is set using the above-described tri-plane display, that is, the display function of the multi-CFM image. Of course, the center position of the sample gate may be set by designating coordinates directly in the three-dimensional space. Alternatively, the sample gate may be set in advance, and the Doppler beam direction may be determined with respect to the sample gate.

  In S102, the posture of an arbitrary cross section passing through the sample gate center point, that is, an arbitrary plane is set. In this case, an actual blood flow direction (central) is observed on the arbitrary cross section while observing an arbitrary CFM image corresponding to the arbitrary cross section. To be included. As described above, the arbitrary cross section includes the center point of the sample gate. For example, the arbitrary plane can be specified by specifying an angle around each axis on a three-axis space defined with reference to such a center point. It is possible to freely set the angle.

  In S103, the user is caused to specify the actual blood flow direction by setting the direction of the correction line on the arbitrary CFM image.

  In S104, the blood flow velocity correction calculation is executed from the posture of the arbitrary cross section set as described above, the rotation angle of the correction line, and the like. By the way, although it is possible to specify the actual blood flow direction directly by the user in the three-dimensional space, since such setting is generally difficult, as described above, the surface setting and its It is desirable to separate the setting of the orientation on the surface.

  Next, the three-dimensional angle correction will be described with reference to FIGS. The blood flow velocity observed by the ultrasonic Doppler method is not an actual blood flow velocity but a velocity component in a direction along the ultrasonic beam. Some conventional ultrasonic diagnostic apparatuses have a function of correcting blood flow velocity based on a correction direction designated by a user on a two-dimensional tomographic image. It is only dimensional and does not determine the actual blood flow velocity. According to the apparatus of the present embodiment, the observed blood flow velocity can be corrected three-dimensionally, that is, the true blood flow velocity can be calculated. This will be specifically described below.

  FIG. 6 shows a three-dimensional absolute space and a three-dimensional relative space. In this example, the three-dimensional absolute space corresponds to a data capture space and is defined by an x, y, z orthogonal coordinate system. The three-dimensional relative space is a three-dimensional space that is redefined with the direction of the Doppler beam passing through the sample gate as the Y direction, and two directions orthogonal to the Y direction are defined as the X direction and the Z direction, respectively. Each space may be defined by polar coordinates.

  In FIG. 6, a vector V represents an actual blood flow velocity vector, and a vector v represents an apparent blood flow velocity vector observed on the Doppler beam (a blood flow velocity component obtained by projecting the vector V on the Y axis). Represents. The crossing angle between them is represented by γ. Incidentally, α indicates an angle component when the angle γ is observed on the YZ plane, and β indicates an angle component when the angle γ is observed on the YX plane. S is a transmission / reception origin.

  In the coordinate system as described above, if the actual blood flow direction (in the illustrated example, the position of B or a line connecting A and B) is specified directly or indirectly by the user, the following is performed. 3D angle correction can be performed. In addition, A shows a sample gate center position, B shows the representative point through which the line which shows a blood flow direction in relation to the sample gate center position A passes (it exists in the front or back of a flow seeing from A). . In this case, the distance between A and B can be arbitrarily determined.

  As shown in FIG. 7, position vectors extending from the origin with respect to points A, B, and S are represented as vector A, vector B, and vector S, respectively. The desired angle γ can be calculated as follows using the outer product of the vector SA from the point S to the point A and the vector BA from the point B to the point A.

  As is clear from the above explanation, by allowing the user to specify the actual blood flow direction (that is, the correction line) in some form, the angle γ between the specified blood flow direction and the Doppler beam direction can be calculated. From the angle γ and the observed blood flow velocity v, the actual blood flow velocity V can be calculated by calculating V = v / cos γ.

  The calculation of the above three-dimensional angle correction is executed by the angle correction unit 46 shown in FIG. The three-dimensional angle correction may be realized by changing the vertical axis (velocity) scale of the Doppler waveform. In the above description, an example of the three-dimensional angle correction method is shown, but other calculation methods may be used.

  In the present embodiment, the above-described arbitrary cross section is defined as a plane including the sample gate center position A. The posture of the arbitrary cross section (for example, specified by a rotation angle around three axes) is variably set by the user. In that case, by observing the CFM image corresponding to the arbitrary cross section, the actual blood flow direction can be recognized from the state of the blood flow or the tissue structure so that the actual blood flow direction is included in the arbitrary cross section. The posture of the arbitrary cross section is adjusted by the user. In this case, it is desirable to adjust the posture so that the range or length of the high-speed blood flow is maximized. After the arbitrary cross section is set, the correction line is designated so as to match the actual blood flow direction on the arbitrary cross section by referring to the CFM image corresponding to the arbitrary cross section.

  The three-dimensional coordinates (xa, ya, za) of the sample gate center position A are already specified, and the three-dimensional coordinates (xs, ys, zs) of the transmission / reception origin are known. Since the length of the correction line is a fixed value, the three-dimensional coordinates (xb, yb, zb) of the representative point B for defining the correction line in relation to the sample gate center position A are based on the Doppler beam direction. It can be obtained from the coordinate information of the arbitrary cross section and the rotation angle of the correction line on the arbitrary cross section. Therefore, if the above calculation formula is executed, the angle γ can be obtained, and the three-dimensional angle correction can be performed using the angle γ. In addition, it is desirable that the angle γ is directly obtained by using a table or the like from the coordinate information of the arbitrary cross section based on the Doppler beam direction and the angle of the correction line on the arbitrary cross section.

  In the embodiment described above, the tissue and the blood flow are combined and expressed. However, if at least one of the two is expressed in constructing the three-dimensional image or the two-dimensional image, the setting method unique to the present embodiment described above. Can be realized. On the other hand, there is an advantage that the actual blood flow method can be specified more accurately while grasping the structure of the tissue and the state of the blood flow by simultaneously expressing the tissue and the blood flow. When the volume rate becomes a problem, a plurality of reception beams may be formed per transmission. For example, if 16 reception beams are simultaneously formed for one transmission, the heart as a moving organ can be observed in real time. In addition, if the scanning range of the ultrasonic beam is limited to a narrow range, the volume rate can be increased, and the beam scanning range for obtaining echo data is different from the beam scanning range for obtaining blood flow data. It is also possible to

1 is a block diagram showing an overall configuration of an ultrasonic diagnostic apparatus according to the present embodiment. It is explanatory drawing which shows a three-dimensional space notionally. It is a figure which shows the example of a display displayed on a display part. It is a figure which shows the other example of a display displayed on a display part. It is a flowchart which shows the operation example of the apparatus shown in FIG. It is a figure for demonstrating coordinate relationship. It is explanatory drawing for demonstrating the calculation of intersection angle (gamma).

Explanation of symbols

  10 3D probe, 12 transmitting / receiving unit, 16 tissue 3D memory, 22 blood flow 3D memory, 26 synthesis calculation unit, 28 graphic generation unit, 30 3D memory, 34 rendering unit, 36 display processing unit, 38 arbitrary CFM image processing unit, 40 Multi-CFM image processing unit, 41 extraction processing unit, 44 Doppler calculation unit, 46 angle correction unit.

Claims (7)

In an ultrasonic diagnostic apparatus that sets a sample gate in a three-dimensional space where ultrasonic waves are transmitted and received and calculates a blood flow velocity based on Doppler information obtained from the sample gate,
Three-dimensional blood flow direction setting means for setting a three-dimensional blood flow direction in relation to the sample gate;
Three-dimensional angle correction means for calculating a blood flow velocity subjected to three-dimensional angle correction based on the cross relationship between the Doppler beam direction passing through the sample gate and the three-dimensional blood flow direction;
An ultrasonic diagnostic apparatus comprising: The apparatus of claim 1.
Arbitrary section setting means for setting an arbitrary section in relation to the sample gate for the three-dimensional space,
Arbitrary tomographic image forming means for forming an arbitrary tomographic image corresponding to the arbitrary cross section;
Including
The three-dimensional blood flow direction setting means includes
Means for designating a two-dimensional blood flow direction on the arbitrary cross-section by allowing a user to set a direction of a two-dimensional blood flow marker displayed on the arbitrary tomographic image;
Means for calculating the three-dimensional blood flow direction based on the coordinate information about the arbitrary cross section and the two-dimensional blood flow direction;
An ultrasonic diagnostic apparatus comprising: The apparatus of claim 2.
The ultrasonic diagnostic apparatus, wherein the arbitrary tomographic image is a two-dimensional tissue blood flow image in which a tissue and a blood flow are represented. The apparatus of claim 3.
Including three-dimensional storage means for storing tissue data and blood flow data acquired in the three-dimensional space,
The arbitrary tomographic image forming means includes:
Means for reading out tissue data corresponding to the arbitrary cross section from the three-dimensional storage means to form a black and white tissue tomographic image;
Means for reading out blood flow data corresponding to the arbitrary cross section from the three-dimensional storage means and forming a color blood flow tomographic image;
Means for synthesizing the tissue tomographic image and the blood flow tomographic image to form a color flow mapping image as the two-dimensional tissue blood flow image;
An ultrasonic diagnostic apparatus comprising: The apparatus of claim 4.
The ultrasonic diagnostic apparatus, wherein the blood flow tomographic image is an image representing high-speed blood flow of a certain speed or higher. The apparatus of claim 1.
The ultrasonic diagnostic apparatus characterized in that the three-dimensional angle correction means calculates an angle formed by the Doppler beam azimuth and the three-dimensional blood flow direction, and executes the three-dimensional angle correction based on the angle. The apparatus of claim 1.
Means for user setting a plurality of cross-sections orthogonal to each other with respect to the three-dimensional space;
Means for forming a plurality of tomographic images corresponding to the plurality of cross sections;
Means for setting a reference point of the sample gate as an intersection coordinate of the plurality of cross sections;
Means for setting the Doppler beam azimuth as a direction connecting a reference point of the sample gate and a transmission / reception origin of ultrasonic waves;
An ultrasonic diagnostic apparatus comprising:

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