JP2017093842A - Ultrasonic volume data processor - Google Patents

Abstract

When a line segment is set on a target tissue image expressed three-dimensionally, a measurement path defined by the line segment can be easily recognized. In addition, the measurement path can be easily corrected.
In addition to a main image, a reference image is displayed. The main image 200 includes a three-dimensional tissue image 92 and a first line segment marker 94 indicating a user-specified line segment. The reference image 202 includes a cross-sectional image 100 showing a cross-section corresponding to a line segment, a second line segment marker 108, and a measurement path marker 114. The measurement path marker 114 indicates a measurement path set along the surface layer of the target tissue. When the line segment 94 is designated as a curve, a cross-sectional image 100 corresponding to a curved surface is displayed. The form of the measurement path can be freely changed by correcting the form of the line segment on the main image 200 or by correcting the form of the measurement path marker 114 on the reference image 202.
[Selection] Figure 7

Description

  The present invention relates to an ultrasonic volume data processing apparatus, and more particularly to a technique for setting a measurement path for a target tissue existing in a three-dimensional space in which ultrasonic waves are transmitted and received.

  The ultrasonic volume data processing device is a device that forms a three-dimensional tissue image as a three-dimensional ultrasonic image. The apparatus is configured as an ultrasonic diagnostic apparatus or an information processing apparatus. The three-dimensional tissue image is an image that three-dimensionally represents a target tissue (target tissue) existing in a three-dimensional space in a living body.

  A method for generating a three-dimensional tissue image will be described. Volume data (ultrasonic volume data) is acquired by transmitting and receiving ultrasonic waves to and from a three-dimensional space in the living body. A plurality of lines of sight (rays) are set for the volume data, and pixel value calculation (rendering processing) is executed for each line of sight. Each pixel value corresponding to each line of sight thus generated is mapped on the projection plane. As a result, a three-dimensional tissue image is constructed. A three-dimensional tissue image may be referred to as a three-dimensional ultrasound image or simply a three-dimensional image.

  As a three-dimensional tissue image forming method, a volume rendering method, a surface rendering method, and the like are known. In the ultrasonic volume data processing apparatus, three cross-sectional images corresponding to three cross-sections (triplanes) orthogonal to each other and cross-sectional images corresponding to arbitrary cross-sections may be formed.

  Patent Document 1 describes that, based on a point designated on a three-dimensional image, a tissue surface position corresponding to the point is determined. The document also describes that a line is specified instead of a point, and that a path length, that is, a distance on the tissue surface is calculated based on the line. However, with the configuration described in this document, the user cannot recognize a specific form of the route that is the distance measurement target. Patent Document 2 calculates the distance from the projection plane (that is, the depth of the surface layer (or surface) of the target tissue) in units of line of sight in parallel with the pixel value calculation in units of line of sight in the execution process of the volume rendering method. It is described to do.

Japanese Patent Laid-Open No. 10-201755 JP 2012-5593 A

  When a line segment is specified on the 3D tissue image, the measurement path corresponding to the line segment is specified as a path along the target tissue surface (surface), and the length (path length) of the measurement path is calculated, It is difficult to recognize the three-dimensional form of the actual measurement path (particularly, the form in the depth direction which is the line-of-sight direction) only by superimposing and displaying the line segment as a marker on the original tissue image. This is because the marker is only a projected image of the measurement path, that is, it does not reflect depth information.

  An object of the present invention is to enable a user to easily recognize a specific form of a measurement path when performing measurement by setting a measurement path for volume data or a three-dimensional tissue image. Alternatively, an object of the present invention is to provide an image that can simultaneously recognize the relationship between the form of the target tissue surface layer and the form of the measurement path. Alternatively, an object of the present invention is to make it possible to change the form of the measurement path correctly and easily.

  The ultrasonic volume data processing device according to the present invention sets a plurality of lines of sight with respect to volume data obtained by transmission and reception of ultrasonic waves, and executes pixel value calculation in units of lines of sight. A three-dimensional tissue image forming means for forming a three-dimensional tissue image as a tissue image; a setting means for setting a measurement path for a target tissue based on a line segment set on the three-dimensional tissue image; Cross-sectional image forming means for forming a cross-sectional image based on cross-sectional data obtained by transmission and reception of sound waves and representing cross-section corresponding to a line of sight passing through the line segment; and the three-dimensional tissue image; Display means for displaying a main image including the first line segment marker indicating the line segment, and a reference image including the cross-sectional image and the measurement path marker indicating the measurement path; You It is intended.

  In the above configuration, the main image includes the three-dimensional image and the first line segment marker. With the first line segment marker, the position and length of the line segment can be grasped in relation to the target tissue image expressed three-dimensionally. However, in general, only by observing the first line segment marker, it is not known what form the measurement path automatically set based on the line segment has in the line-of-sight direction (depth direction). Therefore, in the above configuration, the reference image is displayed together with the main image. The reference image includes a cross-sectional image of the tissue of interest and a measurement path marker indicating the measurement path. The cross section represented by the cross-sectional image corresponds to a surface that is conceived by developing a line segment set on the three-dimensional tissue image in the depth direction, or a surface corresponding to a line of sight that passes through the line segment. That is, the cross-sectional image has a relationship of intersecting (usually orthogonal) with the projection plane. Through such a cross-sectional image, the structure in the cross-section of the tissue of interest can be easily grasped. By observing the measurement path marker superimposed and displayed on the cross-sectional image, it is possible to recognize the form of the actual measurement path in relation to the cross-sectional structure of the tissue of interest. Through the reference image, for example, it can be confirmed that the measurement path does not protrude from the target tissue and that the measurement path does not reach the deep part of the target tissue and is set correctly in the surface layer.

  Cross-sectional data is different from, for example, data cut out from volume data, data configured by extracting a plurality of beam data corresponding to line segments at the stage before volume data configuration, or transmission / reception waves for acquiring volume data. It is data acquired by the transmission and reception of. Preferably, the setting means sets the measurement path along the surface layer of the tissue of interest. Measurement paths may be set for layers and surfaces other than the surface layer (surface).

  Preferably, when calculating a pixel value in line-of-sight units for the volume data, a surface layer depth of the target tissue is specified in line-of-sight units, thereby generating a table in which a plurality of surface layer depths corresponding to the plurality of line-of-sight are registered The setting means sets the measurement path by specifying a row composed of a plurality of surface layer depths corresponding to the line-of-sight row in the table.

  According to this configuration, the surface layer depth of the tissue of interest is calculated for each line of sight in parallel with or before and after the pixel value calculation for each line of sight, and a table is configured from the calculation results. By referring to the contents of the table when the line segment is designated, it is possible to immediately specify the coordinate information that specifies the actual measurement path corresponding to the table. The surface layer (surface) depth of the target tissue may be a distance from the projection plane or the rendering start plane. Or the distance from a viewpoint may be sufficient. Or it may be other than that.

  Preferably, the reference image includes a second line segment marker that is a linear marker that is displayed while being separated from the measurement path marker toward the viewpoint, and that indicates the line segment. According to the second line segment marker, it is possible to intuitively recognize that the line segment projected onto the surface layer of the target tissue is the measurement path marker.

  Preferably, the reference image includes a first line-of-sight marker passing through one end point of the second line segment marker and one end point of the measurement path marker, the other end point of the second line segment marker, and the measurement path. A second line-of-sight marker passing through the other end point of the marker. According to this configuration, the relationship between both ends of the line segment and both ends of the measurement path marker can be intuitively recognized. In particular, it is possible to naturally consider the line-of-sight direction. The measurement path marker corresponds to a trace line when the measurement path is set along the target tissue surface layer.

  Preferably, the image processing apparatus includes a correction unit that corrects the measurement path when a correction operation is performed on the measurement path on the reference image. According to this configuration, the form of the measurement path can be corrected while actually observing the tissue structure on the cross section. That is, the form of the measurement path can be directly changed on the cross section corresponding to the line segment. If necessary, the position, length, form, and the like of the line segment may be corrected on the three-dimensional tissue image, and the form of the measurement path may be corrected on the updated cross-sectional image.

  Preferably, the line segment is a straight line, the cross section is a plane, and the measurement path is a path that changes two-dimensionally. Alternatively, the line segment is a curved line segment, the cross section is a curved surface, and the measurement path is a path that changes three-dimensionally. For example, when an annular line segment is designated, a cross-sectional image such as a development view can be displayed. Such a tomographic image is useful for measuring the fetal abdominal circumference.

  A program according to the present invention is a program for an ultrasonic volume data processing apparatus to execute an ultrasonic volume data processing method, wherein the ultrasonic volume data processing method is volume data obtained by transmitting and receiving ultrasonic waves. Forming a three-dimensional tissue image as a target tissue image viewed from the viewpoint by setting a plurality of lines of sight with respect to each other and executing pixel value calculation for each line of sight, and a line segment on the three-dimensional tissue image Corresponding to a line of sight line passing through the line segment, the cross-sectional data obtained by transmitting and receiving ultrasonic waves, and the step of setting the measurement path for the tissue of interest based on the line segment A step of forming a cross-sectional image based on cross-sectional data representing a cross-section, and a step of generating a main image including the three-dimensional tissue image and a first line segment marker indicating the line segment , And producing a reference image including a measurement path markers indicating the measurement path and the cross-sectional image, a step of simultaneously displaying the the reference image and the main image. The program may be installed in the ultrasonic volume data processing apparatus via a portable recording medium, or the program may be installed in the apparatus via a network.

  According to the present invention, when a measurement path is set for volume data or a three-dimensional tissue image and measurement is performed, the user can recognize a specific form of the measurement path. Or the image which can recognize easily the relationship between the form of an attention tissue surface layer and the form of a measurement path | route can be provided. Alternatively, the form of the measurement path can be easily changed.

It is a block diagram which shows suitable embodiment of the ultrasonic volume data processing apparatus concerning this invention. It is a figure for demonstrating the rendering process with respect to volume data. It is a figure which shows an opacity (opacity) function. It is a figure which shows the example of a general display. It is a flowchart which shows an operation example. It is a figure which shows a three-dimensional structure | tissue image and a cross-sectional image. It is a figure which shows the 1st example of a display of a main image and a reference image. It is a figure which shows the relationship between a three-dimensional tissue image and a cross-sectional image. It is a figure which shows the 2nd example of a display of a main image and a reference image. It is a figure which shows the correction method of a measurement path | route. It is a figure which shows a curvilinear measurement path | route. It is a figure which shows the relationship between a curved line segment and the cross section as a curved surface.

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

  FIG. 1 is a block diagram showing a preferred embodiment of an ultrasonic volume data processing apparatus according to the present invention. This ultrasonic volume data processing apparatus is an ultrasonic diagnostic apparatus in the illustrated example. An ultrasonic diagnostic apparatus is an apparatus that is installed in a medical institution and forms an ultrasonic image by transmitting and receiving ultrasonic waves to and from a living body.

  In this embodiment, the probe 10 is a transducer that includes a 2D array transducer. A three-dimensional transmission / reception space is formed by the probe 10. The space contains the organization of interest. The tissue of interest exists in the subject 12, and is, for example, the heart, liver, fetus or the like. The three-dimensional transmission / reception space can be called a volume data acquisition space.

  The transmission / reception surface of the probe 10 is brought into contact with the surface of the subject 12, and ultrasonic waves are transmitted / received in this state. The 2D array transducer is composed of a plurality of vibration elements arranged vertically and horizontally. An ultrasonic beam is formed by the 2D array transducer, which is electronically two-dimensionally scanned. Thereby, the volume data is acquired. As an electronic scanning method, an electronic sector scanning method, an electronic linear scanning method, and the like are known.

  The volume data may be acquired using a probe of a type that mechanically scans the 1D array transducer. A cMUT type electroacoustic transducer may be used as the 2D array transducer. A probe inserted into a body cavity may be used.

  The transmission unit 14 is an electronic circuit that functions as a transmission beam former. The transmitter 14 supplies a plurality of transmission signals to the array transducer in parallel during transmission. As a result, a transmission beam is formed. At the time of reception, when a reflected wave from the living body is received by the array transducer, a plurality of reception signals are output from the array transducer to the receiving unit 16 in parallel. The receiving unit 16 is an electronic circuit that functions as a receiving beam former. Specifically, a plurality of received signals are subjected to phasing addition processing, thereby forming beam data. Each reception channel circuit included in the reception unit 16 includes an amplifier, an A / D converter, and a delay device. A plurality of received signals after delay processing are input to the adder. In the phasing addition process, a reception dynamic focus technique is applied. The receiving unit 16 may execute parallel reception processing. The transmission / reception control unit 18 controls transmission and reception of ultrasonic waves under the control of the main control unit 42.

  The beam data processing unit 20 performs necessary processing on individual beam data. It includes, for example, a detection circuit, a logarithmic compression circuit, a correlation circuit, and the like. Each beam data consists of a plurality of echo data arranged in the depth direction. Individual beam data output from the beam data processing unit 20 is sent to the three-dimensional coordinate conversion unit 22 and the cross-sectional image creation unit 26.

  The three-dimensional coordinate conversion unit 22 performs coordinate conversion from three-dimensional transmission / reception coordinates to three-dimensional orthogonal coordinates for each echo data, that is, maps individual echo data in a three-dimensional storage space. Actually, each echo data (or interpolation data) after coordinate conversion is stored in the 3D memory 24. Instead of such coordinate conversion at the time of writing, coordinate conversion at the time of reading may be executed. The beam data sequence corresponding to the scanning plane may be converted into scanning plane data by a scan converter, and then the plurality of scanning plane data may be coordinate-converted to constitute volume data. In any case, the 3D memory 24 stores volume data acquired from the three-dimensional transmission / reception space in the living body.

  The cross-sectional image creation unit 26 is configured by a software module or an electronic circuit, which has several functions. The cross-sectional image creation unit 26 has a function of forming three cross-sectional images corresponding to three cross-sections (triplanes) that are orthogonal to each other set for the volume data. The cross-sectional image creation unit 26 has a function of creating a cross-sectional image corresponding to an arbitrary cross-section set for the volume data. Furthermore, when a line segment that defines a measurement path is specified on a three-dimensional tissue image to be described later, it has a function of forming a cross-sectional image representing a cross section defined by the line segment. In forming a cross-sectional image, a predetermined beam data string output from the beam data processing unit is used, or cross-sectional data extracted from volume data is used. A cross-sectional image is formed based on such cross-sectional data. In order to form a high-resolution cross-sectional image with high resolution, interpolation processing or super-resolution processing may be applied to the cross-sectional data or the generated cross-sectional image. The created cross-sectional image data is sent to the display processing unit 34.

  The volume rendering unit 28 is a software module or electronic circuit that forms a three-dimensional tissue image from volume data based on the volume rendering method. Specifically, as will be described later with reference to FIG. 2, a plurality of lines of sight (rays) extending from the viewpoint are set for the volume data, and pixel value calculation (rendering processing) is performed for each line of sight. In the pixel value calculation, a predetermined calculation using opacity is performed for each voxel between the rendering start surface and the rendering end surface (rendering range) set for the volume data. A pixel value that is a calculation result for each line of sight is mapped on the projection plane. The start surface may be a projection surface. The opacity function 30 is a function for determining the opacity from the voxel value, and a specific example thereof will be described later with reference to FIG.

  In the present embodiment, the volume rendering unit 28 has a depth calculation function. This is shown as the depth calculator 32 in FIG. The depth calculator 32 calculates the surface layer (surface) depth of the tissue of interest in line-of-sight units. In the present embodiment, the depth is the distance from the projection surface (rendering start surface) to the surface of the tissue of interest. For each line of sight, the distance calculation is executed in parallel with the pixel value calculation. A distance table is constituted by a plurality of depths (distances) corresponding to a plurality of lines of sight. A storage area in which such a distance table is configured may be referred to as a Z buffer. The distance table is used when a measurement segment corresponding to a line segment is specified when a line segment is designated on the three-dimensional tissue image, as shown later in FIG. Specifically, the depth corresponding to each position on the line segment is specified by reading each distance corresponding to each position constituting the line segment from the distance table. As a result, a measurement path is specified as a three-dimensional path in the three-dimensional transmission / reception space. A calculation formula for pixel value calculation and a calculation formula for distance calculation will be described later. The data of the three-dimensional tissue image is sent to the display processing unit 34. The distance table is sent to the main control unit 42 in the illustrated example.

  The display processing unit 34 is a software module or electronic circuit having an image composition function, a coloring function, and the like. The main image forming function of the display processing unit 34 is shown as a main image forming unit 36 in FIG. Further, the reference image construction function of the display processing unit 34 is shown as a reference image construction unit 38 in FIG. The main image construction unit 36 generates a main image having a three-dimensional tissue image and a line segment marker (first line segment marker) representing a user-specified line segment. The line segment marker is a graphic element as a display element, and is displayed superimposed on the three-dimensional tissue image. The reference image construction unit 38 generates a reference image including a cross-sectional image representing a cross-section corresponding to the line segment and a measurement path marker displayed superimposed on the cross-sectional image. The measurement path marker indicates the form of the measurement path on the cross section as a curve, and is a trace line. The measurement path marker is a display element or a graphic element, like the line segment marker.

  The display unit 40 is, for example, a liquid crystal display, and the main image and the reference image are displayed side by side on the screen. In the present embodiment, when a line segment is designated on the main image, it is represented as a line segment marker (first line segment marker) on the main image, and at the same time, a cross-sectional image representing a cross section corresponding to the line segment. Is formed and displayed. A measurement path marker indicating the measurement path is superimposed and displayed on the cross-sectional image. The measurement path marker is a trace line along the surface layer or the surface of the tissue of interest.

  According to the reference of the line segment marker superimposed on the 3D tissue image, the position and length of the line segment can be grasped in relation to the target tissue, but the depth direction of the measurement path can be grasped. I can't. In the present embodiment, since a cross-sectional image is displayed and a measurement path marker representing the measurement path is displayed there, it is possible to accurately recognize the bending form of the measurement path on the cross section of the tissue of interest. That is, it can be confirmed that the measurement path is correctly set for the surface layer form of the target tissue. In the present embodiment, the reference image includes a line segment marker (second line segment marker) and two line-of-sight markers in addition to the measurement path marker, as shown later in FIG. In the present embodiment, as shown later in FIG. 10 and the like, it is possible to correct the form of the measurement path once set up as needed.

  The main control unit 42 includes a CPU and an operation program. The main control unit 42 controls the operation of each component shown in FIG. Some typical functions that it has are displayed as a plurality of blocks. Specifically, the main control unit 42 includes a line segment setting unit 44, a measurement path setting unit 48, a measurement path correction unit 50, and a path length calculation unit 46. The line segment setting unit 44 is a module that sets a line segment based on the user's coordinate designation on the three-dimensional tissue image. Line segment setting may be fully automated. For example, a line segment may be automatically set based on the image analysis result. The measurement path setting unit 48 projects the designated line segment onto the target tissue surface layer, and specifically reads out a plurality of distance (depth) columns corresponding to the line segment from the distance table described above. This is a module for setting a measurement path along the target tissue surface layer. The measurement path is a path that changes two-dimensionally or a path that changes three-dimensionally. In the former case, a straight line segment is designated, and in the latter case, a curved line segment is designated. When the user performs a correction operation on the measurement path using a pointing device or the like, the measurement path correction unit 50 corrects the measurement path in response to the correction operation. The module that executes such processing is the measurement path correction unit 50. Since the measurement path can be corrected on the cross-sectional image, correct correction can be promptly performed in relation to the structure of the tissue of interest. However, the line segment that forms the basis of the measurement path may be corrected on the three-dimensional tissue image. Such a correction results in a correction of the measurement path. The path length calculation unit 46 is a module that calculates the total length of the measurement path. When the user designates a measurement path for a specific part in a specific organ, the length is automatically calculated. Other measurement units may be provided.

  The control panel 52 is an input device including various input devices such as a trackball. Using this, a line segment is specified, and the line segment and measurement path are corrected.

  Specific examples of some calculation formulas executed by the volume rendering unit will be described. In the above volume rendering, for example, the following calculation is executed.

C _out = C _out-1 + (1-A _out-1 ) ・ A _i・ C _i・ S _i (1)
A _out = A _out-1 + (1-A _out-1 ) · A _i (2)

In the above formula, C _i is the luminance of the i th voxel existing on the line of sight when a 3D image is viewed from a point on the 2D projection plane (when a line of sight passing through the point is set). Value. When N voxels are arranged on the line of sight, in principle, the above calculation is repeated for i = 0 to N. The resulting value Cout becomes the final output pixel value (pixel value). However, if the end condition is satisfied in the middle, the calculation ends at that point and the pixel value is determined. C _out-1 is the result value for the i-1 th voxel. A _i is the opacity defined for the i-th voxel on the line of sight. The opacity takes a value from 0 to 1.0. S _i is a shading weight component calculated from the slope defined for luminance C _i . For example, if the light source and the normal of the surface centered on voxel i match, it will be reflected most strongly, giving 1.0 to Si and giving 0.0 to Si if the light source and normal are orthogonal It is done. C _out and A _out both have an initial value of 0. As shown in equation (2), A _out is accumulated and converges to 1.0 every time it passes through the voxel. Therefore, as shown in the equation (1), when the integrated value Aout-1 of the opacity of the i-1th voxel becomes 1.0 (or a predetermined value), the i-th voxel value Ci (and subsequent values) Voxel value) is not reflected in the output image. The above description is an example, and various methods are known as a volume rendering method.

  There are several methods for calculating the distance. For example, when using the method described in Patent Document 2, the following expression (3) is executed for each line of sight in units of voxels. Here, the distance of the i-th voxel is expressed by Di. Di can be calculated from the pitch between voxels and the voxel number.

D _out = D _out-1 + (1-A _out-1 ) · A _i · D _i (3)

In the above equation (3), the distance _Dout is calculated by the same method as in the equation (1). In other words, it has been required distance D _out weighted by opacity used in the calculation process of the pixel value C _out based on equation (1). Since it is only necessary to be able to specify the surface layer or surface (or a predetermined layer or surface) of the tissue of interest, the voxel depth at the time when the calculation of the above equation (1) is completed (that is, when the opacity is saturated) or based on it The distance may be defined as The distance may be defined as the time when the opacity reaches a threshold value. Depending on the target tissue, the distance may be defined with the depth at which D _out is maximized. Furthermore, an edge detection method may be applied to each line of sight to identify the target tissue surface, and the distance may be defined based on the depth. What is necessary is just to define distance calculation conditions according to the layer, surface, etc. to measure.

  FIG. 2 shows volume data 56 existing in the three-dimensional space. The coordinate system there is specified by XYZ. For reference, reference numerals 58, 60, and 62 indicate three cross sections in the case of performing triplane display. They are in an orthogonal relationship. The projection surface 64 is shown on the viewpoint side of the volume data in the illustrated example. For the volume data 56, for example, a plurality of lines of sight are set in parallel with the line-of-sight direction 66. In FIG. 2, one of the lines of sight 68 is shown. A plurality of voxel data (echo data or interpolation data) exist on the line of sight 68, and the output light amount calculation is sequentially executed in units of individual voxel data. The output light amount as the execution result becomes the pixel value. The pixel value is mapped to the position as the value of the pixel 70 through which the line of sight passes (corresponding to the line of sight). The coordinates on the projection plane 64 are specified by xy. In the volume data 56, there is a focused tissue data chunk 72. When calculating the pixel value in the line-of-sight unit, the position (depth) of the surface layer of the target tissue data chunk 72 is specified. In the embodiment, the distance is the length from the projection plane to the surface layer. A plurality of lines of sight may be set non-parallel.

  FIG. 3 shows an opacity function 76. The horizontal axis indicates the voxel value, and the vertical axis indicates the opacity. In the function 76, the opacity 0 (that is, completely transparent) is set in the section below the voxel value 78, and the opacity increases linearly and relatively steeply from the voxel value 78 to the voxel value 80. In the section above the value 80, a considerably high opacity is set. When such a function 76 is used, the probability that the pixel value calculation in the line-of-sight unit will end at the surface of the target tissue or at a point that does not enter the tissue so much increases. The form of the opacity function 76 shown in FIG. 3 is merely an example.

  FIG. 4 shows a general display mode in the ultrasonic diagnostic apparatus as a reference. It shows a triplane display. On the screen 82 of the display device, a first vertical cross-sectional image 84, a second vertical cross-sectional image 86, and a horizontal cross-sectional image 88 are displayed. A three-dimensional tissue image 90 is also displayed.

  Next, an example of the operation of the apparatus shown in FIG. 1 will be described based on the flowchart shown in FIG. In the description of the individual steps, reference will be made to FIG.

  In FIG. 5, in S10, a line segment is designated as a straight line or a curved line by the user on the three-dimensional tissue image displayed in the real-time operation state or the freeze operation state. In this case, a line segment is designated as a part to be measured. For example, on the right side of FIG. 6, a three-dimensional tissue image 92 is shown as a volume rendering result. On the three-dimensional tissue image 92, the position and length of a line segment marker (first line segment marker) 94 are displayed. By adjusting the length and the like, it is possible to specify a line segment that forms the basis of the measurement path. The line segment marker 94 is a graphic element that represents a line segment. For example, it is expressed in color on a black and white three-dimensional tissue image. The line segment marker 94 shown in FIG. 6 has a linear shape. It is also possible to specify a line segment as a curve. Such an example will be described later with reference to FIG. When the line segment is designated, the coordinates of both ends 96 and 98 may be designated by the user. The control unit recognizes coordinate information about the line segment according to the user designation of the line segment.

  A cross-sectional image 100 representing a cross section corresponding to the line segment is shown on the left side of FIG. It represents a plane constituted by a line of sight passing through a line segment. It represents a surface defined by developing a line segment in the depth direction (line-of-sight direction). The line of sight is conceptually shown on the left side of FIG. Two lines of sight corresponding to both ends are identified by reference numerals 102 and 104. There are a plurality of voxel data on each line of sight. Each voxel data is echo data or interpolation data generated from a plurality of echo data around the voxel. The cross-sectional image is generated based on the voxel data array arranged two-dimensionally.

  In FIG. 5, in S12, a measurement path is specified based on the line segment specified as described above. In this embodiment, a plurality of surface layer coordinates corresponding to a line segment are read from a surface layer coordinate (depth) table (that is, a distance table) indicating the surface layer depth of the target tissue (see S14), thereby specifying the measurement path. Is done. In S16, a reference image corresponding to the designated line segment is formed and displayed. Subsequently, in S18, the path length is calculated and displayed as a numerical value. The contents of S16 and S18 will be described in detail below.

  FIG. 7 shows a first display example. On the display screen, the main image 200 and the reference image 202 are simultaneously displayed. The main image 200 includes a three-dimensional tissue image 92 and a line segment marker (first line segment marker) 94. Reference numerals 96 and 98 indicate both ends of the line segment marker 94. The reference image 202 is a composite image including the cross-sectional image 100 and a graphic image displayed as an overlay on the cross-sectional image 100. The graphic image includes a measurement path marker (trace line) 114, a line segment marker (second line segment). Marker) 108 and line-of-sight markers 122 and 124. Individual graphic elements are expressed in color with mutually distinct hues. As described above, the cross-sectional image 100 shows a cross-section corresponding to a line segment, and in the illustrated example, an image (monochrome B-mode tomographic image) representing a cross-section corresponding to a straight line including the line segment and extending both ends thereof. Image). For this reason, the cross-sectional image 100 covering a wide range beyond both sides of the measurement path marker 114 corresponding to the line segment is displayed.

  The line segment marker 108 is displayed on the viewpoint side of the target tissue, and indicates the horizontal position and length of the line segment. Desirably, the line segment marker 108 is displayed at a position corresponding to the height at which the projection plane exists. However, the display height may be changed. It is desirable to display the line segment marker 108 at a position that does not cover the measurement path marker 114 and the target tissue section. The line segment marker 108 has two end point markers 110 and 112 representing both ends of the line segment in addition to the line forming the main body. By displaying the two line segment markers 94 and 108 in this way, it is possible to intuitively recognize the spatial relationship between the three-dimensional tissue image and the cross-sectional image and the spatial relationship between the line segment and the measurement path marker. It becomes.

  The measurement path marker 114 is a line representing a measurement path corresponding to a line segment. The measurement path is set along the surface layer or surface of the target tissue on the cross section. That is, the measurement path marker 114 is a line expressed in the cross-sectional image 100 so as to trace it in the surface layer of the target tissue. Reference numeral 100A indicates the viewpoint side surface of the target tissue. The measurement path marker 114 has two end point markers 116 and 118 corresponding to both ends of the line segment. A line-of-sight marker 122 is displayed as a line passing through the left end point marker 110 and the left end point marker 116. A line-of-sight marker 124 is displayed as a line passing through the left end point marker 112 and the left end point marker 118. Accordingly, the line-of-sight direction or the line segment projection direction can be intuitively recognized, and the correspondence between the line segment marker 108 and the measurement path marker 114 can be easily grasped. In the lower right of the display screen, a path length indicating the length of the measurement path is displayed as a numerical value. Based on the measurement path, curvature, unevenness, linear distance, luminance distribution, luminance histogram, and the like may be calculated.

  Returning to FIG. 5, in S20, it is determined whether or not correction is to be performed. When correction is performed, correction processing is executed in S22 described in detail later, and thereafter, each step after S12 is repeatedly executed.

  In FIG. 8, a spatial relationship between the three-dimensional tissue image 126 and the cross-sectional image 128 is shown as a conceptual diagram. In addition, labels “before” and “after” are attached in order to correctly understand the spatial correlation between a plurality of images included therein.

  A line segment (and a line segment marker 132) is set on the three-dimensional tissue image 126. The line segment defines a cross section 130 including the line segment (for convenience, the cross section 130 is expressed in a slightly inclined state). The cross section 134 displays the contents of the cross section 130 by changing the direction (with the posture so as to be more visible). On the cross section 134, the relationship between the line segment 136 and the measurement path 138 is shown. A cross-sectional image 128 represents the tissue structure on the cross-sections 130 and 134. At the same time, a line segment marker 140 and a measurement path marker 142 are displayed. A cross section 128 </ b> A represents the back surface of the cross section image 128. A line 140A corresponding to the line segment marker 140 and a line 142A corresponding to the measurement path marker 142 are represented there. In general, when observing a main image and a reference image, the user can easily recognize the spatial relationship shown in FIG. 8 through a plurality of auxiliary graphic elements as described above.

  FIG. 9 shows a second display example. The enlarged main image 144 includes a three-dimensional tissue image 146 and a line segment marker 148. Specifically, the reference image 150 is displayed as an image superimposed on the upper right portion of the main image 144 in the display screen. The reference image 150 is a relatively small image in this example. The display position and the size can be changed by the user. The reference image 150 includes a cross-sectional image 152 and a measurement path marker 154. In this example, the reference line 150 does not include the second line segment marker, but it may be displayed.

  Next, correction of the measurement path will be described. In this embodiment, it is possible to correct the measurement path by correcting the form of the measurement path marker displayed on the cross-sectional image. 10 shows the main image 144 and the reference image 150 shown in FIG. The form of the measurement path marker 154A can be changed by a user operation such as movement of the cursor 156. Specifically, the form of the measurement path marker 154A can be arbitrarily changed by designating the point 158 on the measurement path marker 154A and changing the coordinates of the point 158. For example, when the measurement path marker 154A is not drawn along the surface layer of the target tissue, it is possible to correct the form and correctly set the measurement path in the target tissue. In the example shown in FIG. 10, the correction operation is performed on the reference image 150, that is, the change of the form of the measurement path is allowed only on the cross section as a plane. On the other hand, it is also possible to correct the form of the original line segment itself. Alternatively, it is possible to specify a line segment as a curve from the beginning. This will be described below.

  FIG. 11 shows a main image 160 and a reference image 166. The main image 160 includes a three-dimensional tissue image 162 and a line segment marker 164. In the illustrated example, a curve is specified as a line segment from the beginning, or a straight line is changed to a curve by a correction operation, and as a result, a line segment marker 164 is specified as a curve. The reference image 166 includes a cross-sectional image 168 and a measurement path marker 170. The cross-sectional image 168 is an image representing a cross section as a curved surface corresponding to a line segment as a curved line, as will be described below with reference to FIG. The cross section includes a measurement path, which is displayed as a measurement path marker 170.

  In FIG. 12, as already described, a line segment marker 164 as a curve is set on the three-dimensional tissue image. A cross section 172 is schematically represented on the front side of the three-dimensional tissue image. The cross section 172 is a surface in which the line segment marker 164 is developed in the depth direction (line-of-sight direction). In the cross section 172, a curve 164A corresponding to the line segment marker 164 is drawn, and two lines of sight extending in the line-of-sight direction 174 passing through the both end points are indicated by two lines 178 and 180. In addition, a curve 176 corresponding to the measurement path marker 170 is drawn on the cross section 172. Thus, when a curve is specified on the three-dimensional tissue image, a cross section as a curved surface is set accordingly, and a measurement path is defined on the cross section. In the reference image 166, it is possible to correct the form of the measurement path marker, that is, the measurement path, using the cursor 156 as necessary. As in the case where the cross section is a plane, the measurement path can be easily corrected even if the cross section is a curved surface.

  Combined correction of the position, form, length, etc. of the line segment on the three-dimensional tissue image and correction of the measurement path on the cross-sectional image, that is, the position, form, length, etc. of the measurement path marker, It is possible to set an appropriate measurement path along the site of interest. Note that when manually correcting the coordinates of a certain point belonging to the measurement path marker on the cross-sectional image, the correction has priority over the contents of the depth table. For the correction, a known curve generation algorithm such as spline interpolation can be applied. In the correction, the fixed fixed point and the movable correction point may be specified separately.

  According to the embodiment, it is possible to obtain the path length on the surface layer of the target tissue simply by designating a line segment on the three-dimensional tissue image. In addition, since a line segment can be designated as a curve, a desired measurement path can be freely set. In particular, since the measurement path can be confirmed on the cross-sectional image representing the cross-section corresponding to the line segment, it can be instantaneously confirmed that the measurement is correctly performed. Furthermore, since the form of the measurement path can be corrected on the projection plane and on the cross section, it is possible to prevent confusion when the user designates three-dimensional coordinates. The above method can be applied to medical volume data other than ultrasonic volume data. However, the resolution is relatively low and it is difficult to obtain perspective. It is desirable to apply the above method.

  The above embodiment is an application example of the present invention to an ultrasonic diagnostic apparatus, but the present invention may be applied to an information processing apparatus such as a computer. In that case, ultrasonic volume data is given to the information processing apparatus from an ultrasonic diagnostic apparatus or the like, and processing on the ultrasonic volume data is executed in the information processing apparatus. As described above, distance measurement (path length measurement) is common as a measurement item, but there are various other measurement items. In particular, when performing three-dimensional measurement, it is difficult to grasp a measurement path spatially. Therefore, the above method has great industrial value as a technique for overcoming such a problem.

28 Volume rendering unit, 32 Depth calculation unit, 36 Main image configuration unit, 38 Reference image configuration unit, 44 Line segment setting unit, 46 Path length calculation unit, 48 Measurement path setting unit, 50 Measurement path correction unit, 92 3D Tissue image, 94 first line segment marker, 100 cross-sectional image, 108 second line segment marker, 114 measurement path marker (measurement path), 200 main image, 202 reference image.

Claims (9)

A tertiary that forms a three-dimensional tissue image as a target tissue image viewed from the viewpoint by setting a plurality of lines of sight for volume data obtained by ultrasonic wave transmission and reception and performing pixel value calculation for each line of sight Original tissue image forming means;
Setting means for setting a measurement path for a target tissue based on a line segment set on the three-dimensional tissue image;
Cross-sectional image forming means for forming a cross-sectional image based on cross-sectional data obtained by transmitting and receiving ultrasonic waves and representing cross-section corresponding to a line of sight passing through the line segment;
Display means for displaying a main image including the three-dimensional tissue image and a first line segment marker indicating the line segment, and a reference image including the cross-sectional image and a measurement path marker indicating the measurement path;
An ultrasonic volume data processing apparatus comprising: The apparatus of claim 1.
The setting means sets the measurement path along a surface layer of the tissue of interest;
An ultrasonic volume data processing apparatus. The apparatus of claim 2.
Generation means for specifying a surface layer depth of the tissue of interest in line-of-sight unit when calculating a pixel value in line-of-sight unit for the volume data, thereby generating a table in which a plurality of surface layer depths corresponding to the plurality of line-of-sight are registered Including
The setting means sets the measurement path by specifying a row composed of a plurality of surface layer depths corresponding to the line of sight in the table;
An ultrasonic volume data processing apparatus. The apparatus of claim 1.
The reference image includes a second line segment marker that is a linear marker that is displayed while being separated from the measurement path marker on the viewpoint side, and that indicates the line segment,
An ultrasonic volume data processing apparatus. The apparatus of claim 4.
The reference image is
A first line-of-sight marker passing through one end point of the second line segment marker and one end point of the measurement path marker;
A second line-of-sight marker passing through the other end point of the second line segment marker and the other end point of the measurement path marker;
An ultrasonic volume data processing apparatus comprising: The apparatus of claim 1.
Including correction means for correcting the measurement path when there is a correction operation for the measurement path on the reference image;
An ultrasonic volume data processing apparatus. The apparatus of claim 1.
The line segment is straight,
The cross section is a plane;
The measurement path is a path that changes two-dimensionally,
An ultrasonic volume data processing apparatus. The apparatus of claim 1.
The line segment is a curved line segment,
The cross section is a curved surface;
The measurement path is a path that changes three-dimensionally,
An ultrasonic volume data processing apparatus. An ultrasonic volume data processing apparatus is a program for executing an ultrasonic volume data processing method,
The ultrasonic volume data processing method comprises:
A step of forming a three-dimensional tissue image as a target tissue image viewed from the viewpoint by setting a plurality of lines of sight with respect to volume data obtained by transmission / reception of ultrasonic waves, and executing pixel value calculation for each line of sight When,
Identifying a line segment on the three-dimensional tissue image;
Setting a measurement path for the tissue of interest based on the line segment;
A step of forming a cross-sectional image based on cross-sectional data obtained by transmitting and receiving ultrasonic waves and representing cross-section corresponding to a line of sight passing through the line segment;
Generating a main image including the three-dimensional tissue image and a first line segment marker indicating the line segment;
Generating a reference image including the cross-sectional image and a measurement path marker indicating the measurement path;
Simultaneously displaying the main image and the reference image;
including,
A program characterized by that.