Medical image processing apparatus, medical image processing method, and medical image processing program

Abstract

A medical image processing device that allows tissue to be easily visualized as a ligation target is provided. [Solution] A medical image processing device 100 for visualizing tissue includes an acquisition unit having a function of acquiring volume data including the tissue, a cutting plane setting unit 166 that sets a cutting plane F1 that cuts the tissue in the volume data, and a visualization processing unit 167 that performs processing related to visualization of the tissue. The visualization processing unit 167 performs rendering with ray attenuation on the volume data to generate a rendering image including the tissue cut by the cutting plane F1, and causes a display unit to display display information including the rendering image in which the contours of the tissue on the cutting plane F1 are emphasized.

Description

Technical Field

[0001] The present disclosure relates to a medical image processing apparatus, a medical image processing method, and a medical image processing program.

Background Art

[0002] When excising an organ, a tubular tissue including blood vessels is ligated and transected. It is desired to examine the tubular tissue to be ligated and transected preoperatively. Conventionally, an image display method for visualizing a tubular tissue has been known. This image display method is executed by three-dimensional image processing of a region obtained by cutting an image display for a tubular tissue along a cutting plane along a path representing the center line of the tubular tissue and two-dimensional image processing for the cutting plane. The three-dimensional image processing is image processing by the ray casting method. The two-dimensional image processing is image processing by the MPR method.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] With the technique of Patent Document 1, a cross-section of a tissue can be visualized. However, when generating an image by volume rendering using the ray casting method, it may be difficult to grasp where the position of the tubular tissue (for example, blood vessel) is in the image. Furthermore, it becomes more difficult to grasp at which position in the tubular tissue in the image the cross-section exists. Therefore, it is difficult to visually recognize the tissue to be ligated in the image.

[0005] The present disclosure has been made in view of the above circumstances, and provides a medical image processing apparatus, a medical image processing method, and a medical image processing program in which the tissue to be ligated can be easily visually recognized.

Means for Solving the Problems

[0006] One aspect of the present disclosure is a medical image processing apparatus for visualizing an organ and a tubular tissue contained in the organ, including an acquisition unit having a function of acquiring volume data including the organ, a cutting plane setting unit having a function of setting, with respect to the volume data, a cutting plane for cutting the organ and ligating and separating the tubular tissue during surgery, and a visualization processing unit having a function of performing processing related to visualization of the organ and the tubular tissue. The visualization processing unit performs rendering with light attenuation on the volume data and has a function of generating a rendering image including the organ cut by the cutting plane and the tubular tissue ligated and separated. Knot Of the tubular tissue ligated and separated on the cutting surface The medical image processing apparatus has a function of causing a display unit to display display information including the rendering image in which the contour of the tubular tissue ligated and separated is emphasized.

Advantages of the Invention

[0007] According to the present disclosure, the tissue to be ligated can be easily visually recognized.

Brief Description of the Drawings

[0008]

Figure 1

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Figure 3B

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Figure 4B

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Figure 7A

Figure 7B

Figure 8A

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BEST MODE FOR CARRYING OUT THE INVENTION

[0009] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.

[0010] (Process leading to one embodiment of the present disclosure) Figures 3A and 3B are diagrams for explaining a ligation and dissection site in a conventional ray-cast image. In ligation and dissection, for example, an organ is cut except for blood vessels, the blood vessels are ligated, and the blood vessels are cut in a state where the blood vessels are ligated. FIG. 3A is a diagram showing a cut surface F1X for partially excising an organ Z1X. FIG. 3B is a diagram showing a ray-cast image of an organ Z1X generated based on each voxel located in the direction of arrow αX from the cut surface F1X. Therefore, in FIG. 3B, the inside of the organ Z1X is shown. However, in ray-cast images, shadows often become unclear, and in FIG. 3B, the boundary between the surface of the organ Z1X and the cut surface F1X is not clear. Also, for example, it is difficult to distinguish whether the blood vessel K1X included in the ray-cast image of FIG. 3B is a blood vessel to be ligated and dissected or a blood vessel that does not require ligation and dissection because it turns back to the back side of the organ Z1X. Furthermore, since noise and calcification in the image have relatively large voxel values, it is also difficult to distinguish between noise and calcification and blood vessels in the image. Note that after separating a part of the organ while leaving the blood vessels, the blood vessels may be ligated.

[0011] FIG. 4A represents a first example of a cross-section near a conventional blood vessel. In FIG. 4A, the blood vessel K2X is represented planar, but in reality, it is represented by voxels in a three-dimensional space (the same applies to FIG. 4B). The region located on the right side in FIG. 4A is a mask region MR1X. The region located on the left side in FIG. 4A is a non-mask region MR2X. The numerical values (for example, "0" and "100") described in FIG. 4A indicate voxel values. In FIG. 4A, the voxel value of the blood vessel part is 100, and the voxel value of the organ part that is not a blood vessel is 0. Also, the non-mask region MR2X represents the excision region, and the mask region MR1X represents the remaining region.

[0012] Assuming the viewing direction (for example, the direction from the front left side to the back right side of the paper surface in FIG. 4A) as the projection direction of the virtual ray, without using a mask, volume rendering (for example, ray casting) of voxels with a voxel value of 50 or more visualizes the isosurface F3X and draws the blood vessel K2X. That is, the entire blood vessel K2X shown in FIG. 4A is visualized. In this case, it becomes unclear at which position of the blood vessel to perform excision.

[0013] FIG. 4B shows a second example of a cross-section near a conventional blood vessel. Using a mask with the viewing direction (for example, the direction from the front left side to the back right side of the paper surface of FIG. 4B) as the projection direction of the virtual ray, when volume rendering (for example, ray casting) is performed on voxels with a voxel value of 50 or more, the blood vessel K2X in the mask region MR1X is drawn. At the boundary between the mask region MR1 and the non-mask region MR2, there is the tip K2X1 of the blood vessel to be excised. Therefore, in FIG. 4B, the remaining part of the excised blood vessel K2X is visualized. Also, the tip K2X1 of the blood vessel is visualized as a part of the blood vessel K2X. Therefore, it is difficult to determine whether the tip K2X1 of the blood vessel K2X is the visualized mask boundary between the mask region MR1X and the non-mask region MR2X, or the visualized isosurface F3X of the voxel value. Also, although the actual location to be ligated and transected is position RX, it is difficult to determine whether the blood vessel K2X is the object of ligation and transection.

[0014] In the following embodiments, a medical image processing apparatus, a medical image processing method, and a medical image processing program in which the tissue to be ligated can be easily visually recognized will be described.

[0015] (First Embodiment) FIG. 1 is a block diagram showing a configuration example of a medical image processing apparatus 100 according to the first embodiment. The medical image processing apparatus 100 includes a port 110, a UI 120, a display 130, a processor 140, and a memory 150.

[0016] A CT apparatus 200 is connected to the medical image processing apparatus 100. The medical image processing apparatus 100 acquires volume data from the CT apparatus 200 and performs processing on the acquired volume data. The medical image processing apparatus 100 may be configured by a PC and software installed on the PC.

[0017] The CT apparatus 200 irradiates a subject with X-rays and captures an image (CT image) by utilizing differences in X-ray absorption by tissues in the body. The subject may include a living body, a human body, an animal, etc. The CT apparatus 200 generates volume data including information on any location inside the subject. The CT apparatus 200 transmits the volume data as a CT image to the medical image processing apparatus 100 via a wired line or a wireless line. For capturing the CT image, imaging conditions related to CT imaging and contrast conditions related to administration of a contrast agent may be considered. Note that the contrast may be performed on the arteries or veins of an organ. The contrast may be performed multiple times at different timings according to the characteristics of the organ.

[0018] The port 110 in the medical image processing apparatus 100 includes a communication port, an external device connection port, and a connection port to an embedded device, and acquires the volume data obtained from the CT image. The acquired volume data may be immediately sent to the processor 140 for various processes, or may be stored in the memory 150 and then sent to the processor 140 for various processes when necessary. Also, the volume data may be acquired via a recording medium or a recording media. Also, the volume data may be acquired in the form of intermediate data, compressed data, or a sinogram. Also, the volume data may be acquired from information from a sensor device attached to the medical image processing apparatus 100. The port 110 functions as an acquisition unit that acquires various data such as volume data.

[0019] The UI 120 may include a touch panel, a pointing device, a keyboard, or a microphone. The UI 120 receives any input operation from a user of the medical image processing apparatus 100. The user may include a doctor, a radiological technologist, a student, or other medical staff (Paramedic Staff).

[0020] UI120 accepts various operations. For example, it accepts operations such as specifying a region of interest (ROI) and setting luminance conditions in volume data and images based on the volume data (e.g., 3D images and 2D images described later). The region of interest may include regions of various tissues (e.g., blood vessels, bronchi, organs, bones, brain). Tissues may include diseased tissues, normal tissues, tumor tissues, etc.

[0021] The display 130 may include, for example, an LCD and displays various information. The various information may include 3D images and 2D images obtained from volume data. The 3D images may include volume rendering images, surface rendering images, virtual endoscope images, virtual ultrasound images, CPR images, etc. The volume rendering images may include RaySum images, MIP images, MinIP images, average value images, or ray cast images. The 2D images may include axial images, sagittal images, coronal images, MPR images, etc.

[0022] The memory 150 includes primary storage devices such as various ROMs and RAMs. The memory 150 may also include secondary storage devices such as HDDs and SSDs. The memory 150 may also include tertiary storage devices such as USB memories and SD cards. The memory 150 stores various information and programs. The various information may include volume data acquired by the port 110, images generated by the processor 140, setting information set by the processor 140, and various programs. The memory 150 is an example of a non-transitory recording medium on which programs are recorded.

[0023] The processor 140 may include a CPU, a DSP, or a GPU. The processor 140 functions as a processing unit 160 that performs various processes and controls by executing a medical image processing program stored in the memory 150.

[0024] FIG. 2 is a block diagram showing a functional configuration example of the processing unit 160.

[0025] The processing unit 160 includes a cutting plane setting unit 166 that sets a cutting plane for cutting tissue in the volume data, and a visualization processing unit 167 that performs processing related to the visualization of the tissue. The cutting plane setting unit 166 includes a region processing unit 161. The visualization processing unit 167 includes an image generation unit 162, an emphasis information generation unit 163, and a display control unit 164. The processing unit 160 controls each part of the medical image processing apparatus 100. The processing unit 160 performs processing related to the visualization of the tissue. Note that each part included in the processing unit 160 may be realized as different functions by one piece of hardware, or may be realized as different functions by a plurality of pieces of hardware. Also, each part included in the processing unit 160 may be realized by dedicated hardware components.

[0026] The region processing unit 161 acquires the volume data of the subject, for example, via the port 110. The region processing unit 161 extracts an arbitrary region included in the volume data. The region processing unit 161 may automatically specify a region of interest and extract the region of interest, for example, based on the voxel values of the volume data. The region processing unit 161 may manually specify a region of interest and extract the region of interest, for example, via the UI 120. The region of interest may include regions such as the lungs, liver, bronchi, pulmonary artery, pulmonary vein, portal vein, hepatic vein, etc. The region of interest may be at least a part of an organ to be excised from the subject.

[0027] The region processing unit 161 may divide the organs of the subject by regions. The regions may at least roughly coincide with anatomical regions. The organs may include the lungs, liver, and other organs. The regions may be at least a part of a combination of a plurality of regions. The regions may include sub-regions, sub-sub-regions, etc., which are units in a finer range than the regions.

[0028] The region processing unit 161 may set a cutting plane for cutting the tissue. In this case, the cutting plane may be manually set via the UI 120, or may be automatically set based on the calculation result. For example, when performing region division of the lung, the region processing unit 161 may extract a plurality of regions of the lung and set the boundary surface between the plurality of regions as the cutting plane. The cutting plane may be a plane or a curved surface. The cutting plane may approximately coincide with the ligation and detachment location (ligation and detachment surface).

[0029] The image generation unit 162 generates various images. The image generation unit 162 generates a three-dimensional image or a two-dimensional image based on at least a part of the acquired volume data (for example, the volume data of the extracted region or area). The image generation unit 162 may perform rendering involving light attenuation (for example, ray casting, surface rendering) to generate an image. The image generation unit 162 may generate an image using a mask. When using a mask, it is drawn in the image limited to the voxels in the mask region, and the voxels in the non-mask region are not drawn in the image. Also, multiple masks can be used for each region. Image generation using a mask is disclosed, for example, in Patent Document 1. (Patent Document 1: Japanese Patent No. 4188900)

[0030] The emphasis information generation unit 163 generates emphasis information for emphasizing the contour of the tissue on the cutting plane and the cutting plane itself of the tissue (inside the contour). The emphasis information includes at least contour emphasis information that emphasizes the contour of the tissue on the cutting plane.

[0031] The contour emphasis information may be a ring or the like formed generally along the contour of the tubular tissue on the cutting plane. For example, the contour emphasis information may include information in which the voxel value of the voxels of the contour of the tissue on the cutting plane is made larger than the actually acquired value. The contour emphasis information may include information in which the contour line of the tissue on the cutting plane is thickened. The contour emphasis information may include information in which the voxels of the contour line are made a different color from other voxels adjacent to this contour line.

[0032] The emphasized information may include surface-emphasized information that emphasizes the interior more than the contour of the cut surface. The surface-emphasized information may be a pattern, a texture, a color, a filling, etc. inside a ring indicating the contour on the cut surface. For example, the surface-emphasized information may include information that increases the voxel value of the voxels on the surface of the cut surface to be greater than the actually acquired value. The surface-emphasized information may include information that makes the color of the voxels of the cut surface different from the colors of other voxels adjacent to the cut surface.

[0033] The tissue having the cut surface may be a ligated and transected tissue. This tissue may be, for example, a tubular tissue. The tubular tissue may include blood vessels, lymphatic vessels, bronchi, bile ducts, etc. The ligation and transection may be performed in association with tumor resection of an organ, regional resection of an organ, wedge resection of an organ, etc. Also, the tubular tissue may be a tissue included in an organ (e.g., the lung, the liver). The emphasized information may be information that visualizes the direction of the tubular tissue. The emphasized information may be generated based on the path of the tubular tissue. The emphasized information may be displayed offset from the cut surface.

[0034] The display control unit 164 causes various data, information, and images to be displayed on the display 130. The images include the images generated by the image generation unit 162. Also, the display control unit 164 causes the emphasized information to be superimposed on and displayed on the rendered image.

[0035] FIG. 5 is a diagram for explaining emphasizing the ligated and transected portion. In FIG. 5, a ray-cast image GZ1 including a bronchus 11, a pulmonary artery 12, and a pulmonary vein 13 is shown. In FIG. 5, the bronchus 11, the pulmonary artery 12, and the pulmonary vein 13 have a cut surface F1. The bronchus 11, the pulmonary artery 12, and the pulmonary vein 13 may be visualized by volume rendering (e.g., ray casting). The cut surface F1 may be visualized by surface rendering. The cut surface F1 may substantially coincide with the ligated and transected portion.

[0036] The cross-sectional plane F1 is highlighted by highlighting information. The highlighting information includes at least one of contour highlighting information M1 and surface highlighting information M2. The display control unit 164 highlights and displays the boundary of the voxels visualized on the cross-sectional plane F1 and the non-visualized voxels adjacent to the cross-sectional plane F1 based on the highlighting information. The user can easily visually recognize the boundary of the voxels related to the cross-sectional plane F1 due to the highlighting display of this cross-sectional plane F1. Further, the display control unit 164 may distinguish and display the visualized voxels on the cross-sectional plane F1 and the non-visualized voxels adjacent to the cross-sectional plane F1 by using different display modes (for example, different colors).

[0037] FIG. 6A, FIG. 6B, and FIG. 6C are diagrams showing an example of rendering images before and after resection. FIG. 6A shows a ray-cast image GZ21 including the hepatic vein 21 and the portal vein 22 before resection. FIG. 6B shows a ray-cast image GZ22 in which the cross-sectional plane F1 of the hepatic vein 21 and the portal vein 22 is not highlighted after resection. FIG. 6C shows a ray-cast image GZ23 in which the cross-sectional plane F1 of the hepatic vein 21 and the portal vein 22 is highlighted using highlighting information after resection. Comparing FIG. 6B and FIG. 6C, it can be understood that it is easy to distinguish between simply interrupted blood vessels (here, the hepatic vein 21 and the portal vein 22) and the blood vessels cut by the cross-sectional plane F1 by the contour highlighting information M1 and the surface highlighting information M2 as the highlighting information. Therefore, even when partitioning an area where the complicatedly intertwined hepatic vein 21 and portal vein 22 exist, the location to be cut can be clearly recognized. For example, by making the cross-sectional plane coincide with the dividing plane of the area division, it becomes easy to visually recognize the location where the fine blood vessels should be ligated during the operation of area resection.

[0038] FIG. 7A is a diagram showing a first example of highlighting of each voxel value in a rendering image and a cross-sectional plane F1 of blood vessel K1. In FIG. 7A, highlighting is performed using contour enhancement information M1. In FIG. 7A, blood vessel K1 is represented planar, but is actually represented by voxels in a three-dimensional space (the same applies to FIGS. 7B and 8A). Also, the contour enhancement information M1 is represented by an annular closed curve in a three-dimensional space. The region located on the right side in FIG. 7A is a mask region MR1. The region located on the left side in FIG. 7A is a non-mask region MR2. The numerical values (for example, "0" and "100") described in FIG. 7A indicate voxel values. In FIG. 7A, the voxel values of the blood vessel portion are 100, and the voxel values of the organ portions that are not blood vessels are 0.

[0039] The enhancement information generation unit 163 calculates an intersection point c1 between a boundary surface (mask boundary surface F1A) between the mask region MR1 and the non-mask region MR2 and an isosurface F1B indicating the boundary between voxel values 0 and 100. This intersection point c1 coincides with two points where the contour of the tissue (here, blood vessel K1) on the cross-sectional plane F1 is projected onto the plane of FIG. 7A. The contour of the tissue is indicated by two intersection points c1 in the plane of FIG. 7A, but on three-dimensional volume data, it is indicated by the intersection line between the mask boundary surface F1A and the isosurface F1B. This intersection line is annular and coincides with the contour of the tissue on the set cross-sectional plane F1. Note that the cross-sectional plane F1 is set corresponding to the mask boundary surface F1A, but in FIG. 7A, the cross-sectional plane F1 itself is not visualized.

[0040] FIG. 7B is a diagram showing a second example of highlighting of each voxel value in a rendering image and a cross-sectional plane F1 of a blood vessel. In FIG. 7B, highlighting is performed using contour enhancement information M1 and surface enhancement information M2. In FIG. 7B, similar to FIG. 7A, the mask region MR1, the non-mask region MR2, and the voxel values of each voxel are shown. The surface formed inside the annular closed curve formed by the intersection point c1 represents the cross-sectional plane F1 of the blood vessel. Also, the contour enhancement information M1 is represented by an annular closed curve in a three-dimensional space. The surface enhancement information M2 may be planar or curved. The display control unit 164 may highlight the surface enhancement information M2 by the cross-sectional plane F1 in a display mode (for example, different colors, patterns, line types) different from the isosurface F1B.

[0041] FIG. 8A is a diagram showing a third example of the emphasis display of each voxel value in the rendering image and the cross-sectional plane F1 of the blood vessel. In FIG. 8A, similar to FIGS. 7A and 7B, the mask region MR1, the non-mask region MR2, and the voxel values of each voxel are shown. In FIG. 8A, the emphasis display is performed in consideration of the central path ps1 of the blood vessel K1. The region processing unit 161 may extract the region of the blood vessel K1 and calculate the central path ps1 of the blood vessel K1. The emphasis information generation unit 163 generates a ring RG showing the contour of the cross-sectional plane F1 around the intersection point c2 between the central path ps1 and the mask boundary surface F1A. The display control unit 164 superimposes the contour emphasis information M1 (for example, the ring RG) and the surface emphasis information M2 on the rendering image and displays them. The ring RG is an example of the contour emphasis information M1.

[0042] The direction of the ring RG is adjustable. For example, the emphasis information generation unit 163 may determine the direction of the ring RG based on the direction of the central path ps1 of the blood vessel K1. In this case, the direction of the ring RG may be determined based on the voxel values of 4×4×4 = 64 voxels around the intersection point c2. By adjusting the direction of the ring RG, even when the cross-sectional plane F1 is not perpendicular to the traveling direction of the blood vessel K1 (the direction in which the central ps path extends), the emphasis display using the contour emphasis information M1 and the surface emphasis information M2 perpendicular to the traveling direction of the blood vessel K1 by the ring RG can be performed (see FIG. 8B). Further, the surface emphasis information M2 may be emphasized by displaying the inner surface of the ring RG in a display mode different from that of the isosurface F1B (for example, different colors, patterns, line types).

[0043] FIG. 9 is a diagram for explaining performing the highlighting of the cut surface F1 with an offset. In FIG. 9, the blood vessel K1 branches into a branch E1 and a branch E2. The cut surface F1 passes through both the branch E1 and the branch E2 and is set along the branch E2. In this case, the display control unit 164 may display the ring RG on the branch E1 that extends not along the cut surface F1 without displaying the ring RG on the branch E2 that extends along the cut surface F1. In this case, the display control unit 164 may set an offset surface F2 that is offset from the cut surface F1. The offset surface F2 may or may not be parallel to the cut surface F1. The ring RG may be displayed on the contour of the branch E1 of the blood vessel 1 that passes through both the cut surface F1 and the offset surface F2. The position where the ring RG is drawn may be a position passing through the offset surface F2 or a position different from the offset surface F2. The orientation of the ring RG may or may not be parallel to the cut surface F1.

[0044] Note that the offset between the cut surface F1 and the position where the ring RG is displayed is also applicable to the cases of FIGS. 7A, 7B, and 8A. For example, in FIGS. 7A, 7B, and 8A, it is assumed that the mask boundary surface F1A moves (offsets) in the left - right direction of the drawing along the blood vessel K1. In this case, the display control unit 164 may display the ring RG at an arbitrary position offset from the cut surface F1 (for example, the position of the offset mask boundary surface) for the blood vessel or the branch of the blood vessel that passes through both the non - offset mask boundary surface (the mask boundary surface corresponding to the cut surface F1) and the offset mask boundary surface.

[0045] Also, the display control unit 164 may perform principal component analysis on the figure generated on the cross - section of the blood vessel K1 at the cut surface F1. As a result of the principal component analysis, if the projected figure is closer to a circular shape than a predetermined standard, the ring RG may be displayed. If the projected figure has a flat shape that is not circular compared to the predetermined standard, the ring RG may not be displayed. Also, if the projected figure has a flat shape that is not circular compared to the predetermined standard, the highlighting may be offset.

[0046] FIG. 10 is a diagram showing an example of highlighting of the cut surface F1 in a surface rendering image. In FIG. 10, a surface rendering image GZ3 including a bronchus 31, a pulmonary artery 32, and a pulmonary vein 33 is shown. In FIG. 10, the cut surface F1 is set at the same position as the ligation and dissection site. The cut surface F1 exists in the pulmonary artery 32 and the pulmonary vein 33, and contour highlighting information M1 and surface highlighting information M2 are displayed corresponding to the cut surface F1. Note that in FIG. 10, a part M3 of the pulmonary vein 33 that is disconnected regardless of the cut surface F1 is reflected. Since a part M3 of the disconnected pulmonary vein 33 is not highlighted, the user can recognize that it was photographed in such a way (the pulmonary vein 33 is disconnected).

[0047] FIG. 11 is a diagram showing an example of a surface rendering image GZ4 represented by a polygon mesh. The surface rendering image GZ4 includes a blood vessel K2 represented by a polygon mesh. The blood vessel K2 has two branches, each having a cut surface F1. In this case, the image generation unit 162 divides the polygon along the cut surface F1 to form a new polygon PG. Various image processes are performed using the surface rendering image GZ4 considering the polygon mesh.

[0048] FIG. 12 is a diagram showing a display example of the surface rendering image GZ5 shown in FIG. 11. In the display of the surface rendering image GZ5, usually, the wireframe of the polygon mesh is not drawn. On the other hand, the display control unit 164 draws and displays only the wireframe of the cut surface F1. Here, the wireframe of the cut surface F1 becomes the contour highlighting information M1. Thereby, the blood vessel K2 on the cut surface F1 is highlighted in contour. The display control unit 164 may display all the wireframes and highlight the contour by changing the color and thickness of the wireframe of the cut surface F1.

[0049] FIG. 13 is a diagram showing an example of highlighting a cutting plane F3 for cutting organ Z1. The highlighting information generation unit 163 may generate highlighting information for highlighting the organ Z1 itself on the cutting plane F3. This highlighting information includes at least contour highlighting information M11 that highlights the contour of the organ Z1 on the cutting plane F3. Further, the highlighting information may include surface highlighting information M12 that highlights the inside of the contour of the cutting plane F3. In FIG. 13, using the contour highlighting information M1, M11, the contour of the organ Z1 on the cutting plane F3 and the contours of one or more blood vessels K3 existing in the organ Z1 are highlighted and displayed. In the ray-cast image, it may be difficult to grasp which part of the organ Z1 has been cut. On the other hand, by highlighting the organ Z1 and the blood vessel K3 related to the cutting plane F3, it becomes easier for the user to simultaneously grasp which part of the organ Z1 has been cut and which part of the blood vessels in the organ Z1 has been cut. Also, contour highlighting information M11 may be displayed for the organ Z1, and contour highlighting information M1 and surface highlighting information M2 may be displayed for the blood vessel K3. Thereby, it becomes easier for the user to simultaneously grasp the cutting plane of the organ and the location to be ligated and dissected on the cutting plane of the organ. In FIG. 13, the cutting plane F1 related to the blood vessel K3 is included in the cutting plane F3 related to the organ Z1.

[0050] In this way, the medical image processing apparatus 100 can highlight at the planned ligation and dissection location for a blood vessel crossing the cutting plane F1. Thereby, it becomes easier for the user to grasp the blood vessel planned for ligation and dissection during the surgical planning. Also, it becomes easier for the user to grasp blood vessels inside the organ that are usually difficult to grasp.

[0051] Also, even if the tissue is actually cut at the cutting plane F1 using a mask, at the time when the volume data is acquired, the tissue has not been cut, so there is volume data of the uncut tissue. The display control unit 164 can display the tissue as if it has been cut by making the non-mask region MR2 non-displayed. When masking, it may be difficult to determine whether the cutting plane F1 is at the mask boundary surface or the tissue was simply photographed that way from the beginning. However, by highlighting the cutting plane F1 with highlighting information such as a ring, it becomes clear that the position of the cutting plane F1 is the ligation and dissection location.

[0052] Although various embodiments have been described above with reference to the drawings, it goes without saying that the present disclosure is not limited to such examples. It is obvious that those skilled in the art can conceive of various modifications or corrections within the scope described in the claims, and it is naturally understood that they also belong to the technical scope of the present disclosure.

[0053] For example, the voxel value threshold th2 for calculating the contour of a blood vessel (for example, the voxel value 50 for deriving the isosurface F1B) and the threshold th3 in volume rendering (for example, the threshold for making the pixels used in ray casting opaque or the threshold for generating a surface by the Marching Cubes method, etc.) do not have to match.

[0054] Also, the region processing unit 161 may calculate the contour of the blood vessel not by using the threshold th2 by comparing with the surrounding voxel values, but by simulating the amount of light attenuation accompanying the progress of the virtual ray and calculating the contour of the blood vessel based on the amount of light attenuation. For example, the position where the amount of light attenuation first becomes equal to or greater than the threshold th4 when viewed from the viewpoint side may be regarded as the surface (corresponding to the contour) of the blood vessel. Note that each threshold value may be a fixed value or a variable value.

[0055] Also, the cross-sectional plane F1 may be expressed by a method other than the mask by the region processing unit 161. For example, the cross-sectional plane setting unit 166 may set the cross-sectional plane F1 in the relative coordinate system with respect to the volume data, limit it to the voxels on the back side when viewed from the viewpoint side than the set cross-sectional plane F1, and generate volume rendering using the voxel values of these voxels. In this case, if there are voxels that are made opaque on the cross-sectional plane F1, those voxels will be visualized. As a result, the cross-sectional plane F1 can be visually recognized without using a mask.

[0056] In addition, the region processing unit 161 may create masks representing the cross-sectional plane F1 based on masks representing the shape of the organ Z1 and masks representing the shapes of the blood vessels K1, K2, and K3, respectively. The region processing unit 161 may generate emphasis information based on the intersections of the surfaces of the mask representing the cross-sectional plane F1, the mask representing the shape of the organ Z1, and the masks representing the shapes of the blood vessels K1, K2, and K3. Thereby, for example, compared with the case of emphasizing the cross-sectional plane based on the organ and blood vessels simply extracted as a single mask, depending on how the region masks are created, the ligation and disconnection points can be visualized flexibly. Also, the offset distances may be different for the contours created for each of the organ Z1 and the blood vessels K1, K2, and K3. Thereby, it is possible to simulate the state in which a deviation occurs between the cross-sectional plane F1 of the organ and the ligation and disconnection points of the blood vessels K1, K2, and K3 contained in the organ. Note that the blood vessels K1, K2, and K3 are at least one of the blood vessels K1, K2, and K3.

[0057] In addition, the cross-sectional plane F1 does not have to be a cross-section that completely cuts the organ, and may be a cross-section for making a cut into a part of the organ. Thereby, the intraoperative intermediate state can be expressed by the emphasized display of the cross-sectional plane F1. Also, the emphasized display of the cross-sectional plane F1 can be applied even when making a cut expecting the proliferation of hepatocytes. In this case, the processing unit 160 may perform deformation simulation taking into account the deformation of the liver in which a piece is pulled after making a cut into a part of the organ, and perform an emphasized display of the deformed cross-sectional plane F1.

[0058] In addition, the emphasized display of the cross-sectional plane F1 may be performed with an offset from the cross-sectional plane F1. The display control unit 164 may, for example, perform an emphasized display using a ring RG or the like in front of the line-of-sight direction with respect to the blood vessel path and the cross-sectional plane F1. This is because in surgery, when the organ is incised and the blood vessel is exposed, ligation and disconnection are performed at an appropriate position in the shape of the blood vessel, so the actual ligation and disconnection point may be located in front of the line-of-sight direction of the cross-sectional plane F1, or the emphasized display may be easier to view when performing an emphasized display together with the rendered image.

[0059] Also, the rendering image may include both an image portion obtained by volume rendering and an image portion obtained by surface rendering. For example, the contour of the organ itself may be visualized by surface rendering, and blood vessels may be visualized by volume rendering. For example, when simulating segmental resection of an organ, the segment of the organ may be visualized by surface rendering, and blood vessels may be visualized by volume rendering.

[0060] Also, volume rendering may include sub - species of the ray - casting method and rendering methods other than the ray - casting method. In volume rendering, it may be limited to rendering with light attenuation. This rendering may include Stochastic Ratcast, Cinematic Volume Rendering Technique, ray - tracing for volume data, etc. Also, in the case of rendering that combines the ray - casting method and the MIP method, the tissue whose cross - sectional plane F1 is highlighted may be visualized by the ray - casting method, and other organs may be visualized by the MIP method. Thus, highlighting information may be superimposed on the organ visualized by the MIP method. Also, the rendering may include surface rendering. In surface rendering, the surface rendered on the cross - sectional plane F1 may or may not be stretched.

[0061] Also, the display control unit 164 may not attach highlighting information to the rendering image after rendering, but may be configured such that highlighting information is attached at the rendering stage. For example, when the image generation unit 162 performs surface rendering, it may be set to perform rendering (contour - emphasizing rendering) for emphasizing the contour at the rendering stage, and may perform contour - emphasizing rendering. The emphasis of this contour may include the emphasis of the contour of the tissue on the cross - sectional plane. Note that this is not limited to surface rendering and may also be applied to volume rendering.

[0062] Further, the medical image processing apparatus 100 may include at least a processor 140 and a memory 150. The port 110, the UI 120, and the display 130 may be external to the medical image processing apparatus 100.

[0063] Also, it was exemplified that the volume data as the imaged CT image is transmitted from the CT apparatus 200 to the medical image processing apparatus 100. Instead of this, the volume data may be transmitted to a server (for example, an image data server (PACS) (not shown)) on the network so as to be once stored and stored. In this case, when necessary, the port 110 of the medical image processing apparatus 100 may acquire the volume data from the server or the like via a wired line or a wireless line, or may acquire it via an arbitrary storage medium (not shown).

[0064] Also, it was exemplified that the volume data as the imaged CT image is transmitted from the CT apparatus 200 to the medical image processing apparatus 100 via the port 110. This shall include the case where the CT apparatus 200 and the medical image processing apparatus 100 are substantially combined as one product. Also included is the case where the medical image processing apparatus 100 is treated as the console of the CT apparatus 200.

[0065] Also, although it was exemplified that the CT apparatus 200 images an image and generates volume data including information inside the subject, an image may be imaged by another apparatus and volume data may be generated. The other apparatus includes an MRI (Magnetic Resonance Imaging) apparatus, a PET (Positron Emission Tomography) apparatus, an angiography apparatus, or other modality apparatuses. Also, the PET apparatus may be used in combination with other modality apparatuses.

[0066] Also, the operation in the medical image processing apparatus 100 can be expressed as a medical image processing method in which the operation is defined. Also, it can be expressed as a program for causing a computer to execute each step of the medical image processing method.

[0067] (Summary of the above embodiment) One aspect of the above embodiment is a medical image processing apparatus 100 for visualizing tissue, which includes an acquisition unit (e.g., port 110) having a function of acquiring volume data including the tissue, a cutting plane setting unit 166 for setting a cutting plane for cutting the tissue in the volume data, and a visualization processing unit 167 having a function of performing processing related to visualization of the tissue. The visualization processing unit 167 may have a function of performing rendering with light attenuation on the volume data and generating a rendering image including the tissue cut by the cutting plane. The visualization processing unit 167 may have a function of causing a display unit (e.g., display 130) to display display information including the rendering image in which the contour of the tissue on the cutting plane is emphasized.

[0068] Thereby, the medical image processing apparatus 100 can be easily identified by checking the highlighted display of where the cutting plane is in the entire tissue. In the highlighted display, for example, although the branches of the blood vessels also extend to the tip of the cutting plane, a mark (an example of highlighted information) indicating that the tip side beyond the cutting plane is to be resected can be attached. Also, even when not using a mask, the user can identify which position of the tissue is to be resected by checking the highlighted display. Also, even when using a mask, the user can easily determine whether the part of the tissue on the root side (non-terminal side) of the cutting plane is visualized or the isosurface of the voxel value is visualized based on the presence or absence of the highlighted display of the contour of the cutting plane. As a result, in preoperative planning and intraoperative navigation, the user can appropriately grasp the locations to be resected and ligated and dissected.

[0069] The cut plane setting unit 166 may have a function of setting a cut plane F1 based on a mask boundary plane F1A, which is a boundary between a mask region MR1 including voxels to be rendered and a non-mask region MR2 including voxels not to be rendered, among a plurality of voxels included in the volume data. The visualization processing unit 167 may have a function of excluding the voxel values ​​of each voxel in the non-mask region MR2 and generating and displaying a rendering image based on the voxel values ​​of each voxel in the mask region MR1.

[0070] This makes the portion of the tissue to be resected distal to the cutting plane invisible, allowing the user to more intuitively understand that the tissue will be cut by the cutting plane.

[0071] Furthermore, the tissue may be a tubular tissue (for example, a blood vessel K1). This makes it easier for the user to visually confirm the excision site of the tubular tissue, which is often smaller than an organ. Furthermore, the tubular tissue may be included in the organ Z1. This allows the user to visually confirm the cut portion of the tubular tissue inside the organ that cannot be seen from the outside. Furthermore, the processing unit 160 may display a rendering image indicating the direction of the tubular tissue. This allows the user to check the resection location taking into account the direction of the tubular tissue, even when the tubular tissue is cut obliquely relative to the path, making it easier to actually resect the tissue.

[0072] Furthermore, the visualization processing unit 167 may offset the contour of the tubular tissue on the cutting plane F1 from the cutting plane F1 to highlight it and display the rendering image. This allows the medical image processing device 100 to clearly display highlighting information at the tissue location corresponding to the resection location when the cutting plane F1 set by the medical image processing device 100 differs from the location that will actually be cut in surgery, and also allows the medical image processing device 100 to quickly set the cutting plane F1. Also, it is possible to simulate the occurrence of a deviation between the cutting plane F3 of an organ and the location where the tubular tissue contained in the organ is to be ligated and cut.

[0073] In addition, the tissue may be an organ. As a result, even when it is difficult to grasp the organ in the rendering image, the outline of the organ is made clear, making it easier for the user to visually recognize the organ. In addition to emphasizing the cross-section of the tubular tissue, the visualization processing unit 167 may emphasize the cross-section of the organ including the tubular tissue and display a rendering image. This makes it easier for the user to simultaneously grasp the cross-section F3 of the organ and the location where ligation and dissection are to be performed on the cross-section F3 of the organ. In addition, the visualization processing unit 167 may emphasize the inside of the contour in the cross-section and display a rendering image. This makes it easier for the user to appropriately grasp the cross-section of the tissue. In addition, the rendering image may be a volume rendering image. Although a volume rendering image visualizes the internal state of the tissue in a three-dimensional space on a two-dimensional plane and it may be difficult to grasp a specific position in the three-dimensional space, the above-described highlighting makes it easier to visually recognize the resection site.

[0074] One aspect of the above embodiment is a medical image processing method for visualizing tissue, including steps of acquiring volume data including the tissue, setting a cross-section F1 for cutting the tissue in the volume data, performing rendering with ray attenuation on the volume data to generate a rendering image including the tissue cut by the cross-section, and displaying, on a display unit, display information including the rendering image in which the contour of the tissue on the cross-section is emphasized.

[0075] One aspect of the present embodiment may be a medical image processing program for causing a computer to execute the above-described medical image processing method.

Industrial Applicability

[0076] The present disclosure is useful for a medical image processing apparatus, a medical image processing method, a medical image processing program, etc. in which the tissue to be ligated can be easily visually recognized.

Explanation of Signs

[0077] 100 Medical Image Processing Device 110 Port 120 User Interface (UI) 130 Display 140 Processor 150 Memory 160 Processing Unit 161 Region Processing Unit 162 Image Generation Unit 163 Emphasis Information Generation Unit 164 Display Control Unit 166 Cross-Section Setting Unit 167 Visualization Processing Unit 200 CT Device C1 Intersection Point F1 Cross-Section F1A Mask Interface F1B Contour Surface K1, K2 Blood Vessels M1 Contour Emphasis Information M2 Surface Emphasis Information MR1 Mask Region MR2 Non-Mask Region ps1 Central Path RG Ring

Claims

1. A medical image processing apparatus for visualizing an organ and a tubular tissue contained in the organ, comprising an acquisition unit having a function of acquiring volume data including the organ, a cutting plane setting unit having a function of setting, with respect to the volume data, a cutting plane for cutting the organ and ligating and separating the tubular tissue during surgery, and a visualization processing unit having a function of performing processing related to visualization of the organ and the tubular tissue, wherein the visualization processing unit performs rendering with light attenuation on the volume data, and has a function of generating a rendering image including the organ cut by the cutting plane and the tubular tissue ligated and separated, and has a function of causing a display unit to display display information including the rendering image in which the contour on the cutting plane of the tubular tissue to be ligated and separated is emphasized. Medical image processing apparatus.

2. The cutting plane setting unit has a function of setting the cutting plane based on a mask boundary surface that is a boundary between a mask region including voxels to be rendered and a non-mask region including voxels outside the rendering target among a plurality of voxels included in the volume data, and the visualization processing unit has a function of excluding the voxel values of each voxel in the non-mask region and generating and displaying the rendering image based on the voxel values of each voxel included in the mask region. The medical image processing apparatus according to claim 1.

3. The visualization processing unit emphasizes the inside of the contour on the cutting plane and displays the rendering image. The medical image processing apparatus according to claim 1 or 2.

4. The rendering image is a volume rendering image. The medical image processing apparatus according to any one of claims 1 to 3.

5. A medical image processing method for visualizing an organ and a tubular tissue contained in the organ, comprising: obtaining volume data including the organ; setting, with respect to the volume data, a cutting plane for cutting the organ and ligating and separating the tubular tissue during surgery; performing a process related to visualization of the organ and the tubular tissue; The step of performing the process related to visualization includes: performing rendering with light attenuation on the volume data to generate a rendering image including the organ cut by the cutting plane and the tubular tissue ligated and separated; causing a display unit to display display information including the rendering image in which the contour on the cutting plane of the tubular tissue to be ligated and separated is emphasized. A medical image processing method.

6. A medical image processing program for causing a computer to execute the medical image processing method according to claim 5.

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