JP2018089343A - Medical image processing apparatus, control method and program of medical image processing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the visibility at the time of overlappingly displaying images displayed in the different rendering methods in a medical image processing apparatus.SOLUTION: A medical image processing apparatus includes: an image input unit which inputs three-dimensional volume data imaged by a medical imaging apparatus; volume rendering means which generates a volume rendering image on the basis of the three-dimensional volume data input to the image input unit; surface rendering means which generates a surface rendering image on the basis of the three-dimensional data; depth information acquisition means which acquires depth information indicating the length from the prescribed view point position to the three-dimensional volume data in the three-dimensional space; and display control means which overlappingly displays the volume rendering image with respect to the surface rendering image after displaying the surface rendering image on the basis of the depth information acquired by the depth information acquisition means.SELECTED DRAWING: Figure 6

Description

  The present invention relates to a medical image processing apparatus for a three-dimensional image, a control method for the medical image processing apparatus, and a program.

  As a conventional medical image processing apparatus, an apparatus that tracks and displays the extending direction of a nerve fiber (white matter fiber) in a living body is known. The medical image processing apparatus analyzes the running of nerve fibers using, for example, a diffusion-weighted image (DWI) taken by a nuclear magnetic resonance imaging (MRI) apparatus. Then, the medical image processing apparatus visualizes the analysis result of the nerve fiber and the living tissue imaged by the MRI apparatus by a three-dimensional display, and displays them by superimposing them.

  Patent Document 1 discloses a medical image processing apparatus that performs rendering by rendering three-dimensional data indicating nerve fibers and three-dimensional data including biological tissue by different rendering methods. The medical image processing apparatus calculates a distance from a viewpoint position to a voxel having a predetermined opacity or higher among voxels of a living tissue displayed by the volume rendering method. Then, the medical image processing apparatus specifies the display position of the image obtained by rendering the nerve fiber using the calculated distance.

JP 2012-34772 A

  However, in the calculation method of the medical image processing apparatus of Patent Document 1, the distance from the viewpoint position to the voxel may not be accurately calculated depending on the setting of the opacity of the voxel. For this reason, there is a possibility that an image of a living tissue displayed by the volume rendering method and a nerve fiber image displayed by another rendering method are superimposed and displayed with an incorrect positional relationship. In view of the above problems, an object of the present invention is to improve visibility when an image rendered by a different rendering method is displayed in a superimposed manner in a medical image processing apparatus.

  In order to achieve the above object, a medical image processing apparatus according to the present invention includes an image input unit that inputs three-dimensional volume data captured by a medical image capturing device, and three-dimensional volume data input to the image input unit. Volume rendering means for generating a volume rendering image based thereon, surface rendering means for generating a surface rendering image, and depth information for acquiring depth information indicating a length from a predetermined viewpoint position to the three-dimensional volume data in a three-dimensional space Information display means, and display control means for displaying the volume rendering image superimposed on the surface rendering image after displaying the surface rendering image based on the depth information acquired by the depth information acquisition means, It is characterized by having

  According to the present invention, in a medical image processing apparatus, it is possible to improve the visibility when images displayed by different rendering methods are superimposed and displayed.

It is a figure which shows an example of the hardware constitutions of the medical image diagnostic apparatus in this embodiment. It is a figure which shows the function of the medical image diagnostic apparatus in this embodiment. It is a figure which shows an example when a superimposed display is not appropriate. It is a figure which shows an example at the time of performing a superimposition display appropriately. It is a figure which shows the depth information which the depth information acquisition part in this embodiment acquires. It is a flowchart which shows the analysis / display process of the medical image diagnostic apparatus in this embodiment. It is a flowchart which shows the determination process of the superimposition position in this embodiment. It is a flowchart which shows the switching process of the display order of the image in this embodiment.

  Hereinafter, this embodiment will be described in detail with reference to the drawings.

  FIG. 1 is a diagram illustrating an example of a hardware configuration of the medical image processing apparatus 100. Note that the hardware configuration of the medical image processing apparatus 100 shown in FIG. 1 is not limited to this.

  The medical image processing apparatus 100 is a general-purpose computer such as a personal computer. The medical image processing apparatus 100 generates volume data (three-dimensional data) by stacking two-dimensional medical images (hereinafter referred to as two-dimensional medical images) obtained by tomography with a CT apparatus, MRI, or the like. . The two-dimensional medical image is a DICOM (Digital Imaging and Communication in Medicine) image. Then, it is possible to display a three-dimensional medical image (hereinafter referred to as a three-dimensional medical image) generated by performing volume rendering on the volume data. The medical image processing apparatus 100 may be a so-called personal computer or a server, but is preferably a computer specialized for processing medical images such as a workstation. Further, the medical image processing apparatus 100 may be a tablet terminal or a portable terminal that includes a touch panel.

  The CPU 101 comprehensively controls each device and controller connected to the system bus 104.

  Further, the ROM 102 or the external memory 111 stores a basic input / output system (BIOS) that is a control program of the CPU 101 and an operating system program. The external memory 111 stores various programs necessary for realizing each function. The RAM 103 functions as a main memory, work area, and the like for the CPU 101.

  The CPU 101 implements various operations by loading a program or the like necessary for execution of processing into the RAM 103 and executing the program.

  The input controller 105 controls input from an input device 109 such as a keyboard or a pointing device such as a mouse.

  The video controller 106 controls display on a display device such as the display device 110. The display device may be a CRT or a liquid crystal display device.

  The memory controller 107 controls access to the external memory 111 such as a hard disk, a flexible disk, or a card type memory connected to the PCMCIA card slot via an adapter. The external memory 111 (storage means) stores a boot program, browser software, various applications, font data, user files, editing files, various data, and the like.

  The communication I / F controller 108 is connected to and communicates with an external device via a network, and executes communication control processing on the network. For example, Internet communication using TCP / IP is possible.

  Note that the CPU 101 can perform display on the display device 110 by executing outline font rasterization processing on a display information area in the RAM 103, for example. Further, the CPU 101 enables a user instruction with a mouse cursor (not shown) on the display device 110.

  Various programs and the like used by the medical image processing apparatus 100 in the present embodiment to execute various processes to be described later are recorded in the external memory 111 and are executed by the CPU 101 by being loaded into the RAM 103 as necessary. Is. Furthermore, definition files and various information tables used by the program in the present embodiment are stored in the external memory 111.

  FIG. 2 is a diagram illustrating an example of a functional configuration of the medical image processing apparatus 100. Each function shown in FIG. 2 is a component realized by each hardware and various programs shown in FIG. The functional configuration of the medical image processing apparatus 100 is not limited to this.

  The medical image processing apparatus 100 includes an image input unit 201, a surface rendering image generation unit 202, a volume rendering image generation unit 203, a depth information acquisition unit 204, and a display control unit 205.

  The image input unit 201 is a functional unit that inputs 3D volume data captured by a medical image capturing apparatus. The medical imaging apparatus is a medical modality and includes a CT apparatus, an MRI apparatus, and the like.

  The three-dimensional volume data is usually a three-dimensional array, and the elements of each array are represented by 8 to 16-bit integer values or floating-point data. The image input unit 201 is configured to be able to input an image stored in the external memory 111 with reference to the external memory 111. In the external memory 111, for example, a plurality of images taken with an MRI apparatus are stored. For example, the plurality of images are a T1-weighted image, a T2-weighted image, a DWI, and the like.

  The T1-weighted image is an image in which the longitudinal relaxation time of protons contained in the biological tissue is emphasized. The T2-weighted image is an image in which the transverse relaxation time of protons included in the biological tissue is emphasized. The DWI is an image of disturbance of spin phase generated in protons contained in a living tissue by a pair of gradient magnetic fields applied from a predetermined direction. The external memory 111 is not limited to an image photographed with an MRI apparatus, and may store an image photographed with a CT apparatus or the like.

  The image stored in the external memory 111 is, for example, image data in a format conforming to the DICOM standard. In the DICOM standard, the name, model number, manufacturer name, or the like of the MRI apparatus that captured the image is stored in a data storage position indicated by a predetermined tag. Note that DWI imaging conditions are stored at different positions for each MRI apparatus or manufacturer. The imaging conditions include, for example, an MPG tilt direction (Gradient Orientation), the number of tilt directions, and a b value indicating the strength of the influence of MPG.

  The image input unit 201 has a function of inputting a plurality of DWI and T2-weighted images obtained by photographing a living tissue to be observed. The image input unit 201 has a function of outputting the input image to the surface rendering image generation unit 202 and the volume rendering image generation unit 203.

  The input device 109 has a function of inputting a user operation. For example, the input device 109 is a user interface such as a mouse or a keyboard. The input device 109 has a function of inputting a start point area, an end area, an avoidance area, a tensor analysis method, a mouse point position, and the like, which are specified by a user operation, which will be described later.

  The surface rendering image generation unit 202 has a function of performing a diffusion tensor analysis using a plurality of DWI and T2-weighted images and generating a diffusion tensor image (DTI: Diffusion Tensor Imaging). Then, the surface rendering image generation unit 202 tracks the extending direction of the nerve fiber from the diffusion tensor image, and specifies the three-dimensional position of the nerve fiber. The surface rendering image generation unit 202 has a function of generating a rendering image while generating three-dimensional data by the surface rendering method using the identified three-dimensional position of the nerve fiber. Hereinafter, diffusion tensor analysis will be described.

  The surface rendering image generation unit 202 has a function of acquiring imaging conditions assigned to each DWI when performing diffusion tensor analysis. In order to acquire each imaging condition of the DWI, for example, the surface rendering image generation unit 202, based on the tag storing the name of the MRI apparatus or the manufacturer of the manufacturer, the name of the MRI apparatus that captured the analysis target DWI or It is configured to be able to acquire the manufacturer name of the device. The surface rendering image generation unit 202 is configured to be able to refer to the tag information table in order to specify the data storage position of the imaging condition based on the MRI apparatus name or the manufacturer name. In the tag information table, a table in which the tag and the meaning indicated by the tag are associated is stored in association with each MRI apparatus or each manufacturer of the MRI apparatus. The surface rendering image generation unit 202 has a function of acquiring the MPG tilt direction, the number of tilt directions, and the b value, which are imaging conditions of the target DWI, and performing diffusion tensor analysis.

  The surface rendering image generation unit 202 is configured to be able to generate a DTI using a tensor analysis method selected from a plurality of tensor analysis methods. The surface rendering image generation unit 202 is configured to be able to generate a DTI by a tensor analysis method selected by the user via the input device 109, for example. For example, the surface rendering image generation unit 202 is configured to be able to execute a 1 tensor analysis method or a 2 tensor analysis method. Here, the 1 tensor analysis method expresses the diffusion anisotropy as one direction using one tensor, and the 2 tensor analysis method uses the two tensors to express the diffusion anisotropy in two directions. Is expressed as As described above, the case where the surface rendering image generation unit 202 specifies the three-dimensional position of the nerve fiber by the diffusion tensor analysis has been described, but the target of the surface rendering is not limited to this.

  The volume rendering image generation unit 203 has a function of generating a volume rendering image based on the three-dimensional volume data input to the image input unit. In the present embodiment, an example of rendering by the volume rendering method using the DTI output by the surface rendering image generation unit 202 is shown. For example, the volume rendering image generation unit 203 inputs a plurality of DTIs, constructs a three-dimensional image model with voxels each associated with a DTI scalar quantity, and sets display attributes such as opacity for each voxel. It has a function to be given according to the scalar quantity. Then, the volume rendering image generation unit 203 expresses light source attenuation along the line-of-sight direction with all voxels. For example, the volume rendering image generation unit 203 calculates the luminance value of the voxel by multiplying the incident light source amount and the opacity of the voxel. The volume rendering image generation unit 203 generates a volume rendering image by sequentially integrating the above processes in the line-of-sight direction.

  The rendering images generated by the surface rendering image generation unit 202 and the volume rendering image generation unit 203 are two-dimensional array elements.

  The depth information acquisition unit 204 acquires depth information indicating the length from a predetermined viewpoint position to the three-dimensional volume data in the three-dimensional space based on the three-dimensional volume data. Specifically, the depth information acquisition unit 204 identifies a voxel having an opacity greater than a predetermined value from the three-dimensional volume data, and calculates a distance from the predetermined viewpoint to the voxel. Then, the depth information acquisition unit 204 acquires the calculated distance as a distance to the living tissue in the line-of-sight direction (a distance from the viewpoint to the surface in volume rendering).

  The depth information acquisition unit 204 calculates the length from the predetermined viewpoint position in the three-dimensional space to the nerve fiber displayed by the surface rendering method (second depth information) based on the three-dimensional volume data.

  Here, for example, the depth information is obtained by extending a line connecting the virtual viewpoint position set in the virtual three-dimensional space and the position of the corresponding two-dimensional array on the rendering image plane, It is obtained by integrating the intersecting positions. The depth information acquisition unit 204 can use the value of the Z buffer (depth buffer) as the depth information.

  The display control unit 205 performs display control on the display device 110 so as to superimpose and display the volume rendering image and the surface rendering image. Here, the display control unit 205 displays the surface rendering image based on the depth information acquired by the depth information acquisition unit 204 and then superimposes the volume rendering image on the surface rendering image. With the display control, the display control unit 205 can superimpose and display without impairing visibility regardless of the opacity value set for each voxel of the three-dimensional volume data.

  Next, depth information acquisition processing by the depth information acquisition unit 204 will be described with reference to FIG. FIG. 3A is a diagram illustrating the depth information of the three-dimensional volume data when the opacity is higher than a predetermined threshold. FIG. 3B is a diagram illustrating the depth information of the three-dimensional volume data when the opacity is lower than a predetermined threshold. FIG.3 (c) is a figure which shows the depth information of the three-dimensional data of a nerve fiber. In FIG. 3, depth information 302 is the distance from the reference position (projection plane) 300 of the viewpoint to the three-dimensional volume data 301.

  As shown in FIG. 3A, when the opacity of the voxel in the three-dimensional volume data 301 is higher than a predetermined threshold, the depth information 302 is calculated accurately. In this case, the depth information 302 is a distance from the viewpoint reference position (projection plane) 300 to the surface of the three-dimensional volume data 301.

  Next, as shown in FIG. 3B, when the opacity of the voxel of the three-dimensional volume data 301 is lower than a predetermined threshold, the depth information 302 is not accurately calculated. That is, the depth information 302 is a distance from the reference position (projection plane) 300 of the viewpoint to the back surface of the three-dimensional volume data 301. As a specific example, when opacity lower than a predetermined threshold is set for the voxel values of the skull and brain cells, the distance from the reference position of the viewpoint to the back of the skull is the depth information 302. Is set.

  Next, as shown in FIG. 3C, there is no opacity in the case of three-dimensional data used for surface rendering. Therefore, the depth information acquisition unit 204 can accurately calculate the depth information (second depth information) of the three-dimensional data.

  Here, the predetermined threshold value of opacity will be described. For example, if the predetermined threshold is set too low, the selection accuracy when selecting a part of the volume rendering image with the input device 109 or the like may be reduced. Therefore, it is not preferable to make the predetermined threshold value of opacity extremely small, and it is difficult to set depth information accurately in all opacity levels.

  Next, a case where the depth information is set as shown in FIG. 3B and the display control unit 205 performs display control in the order of the volume rendering image and the surface rendering image will be described with reference to FIG. To do. FIG. 4 is an example of a rendered image displayed on the display device 110.

  In this case, the nerve fiber 401 that should exist inside the living tissue 402 is two-dimensionally displayed on the front side of the living tissue 402 on the display device 110.

  Next, the case where the depth information is set as shown in FIG. 3B and the display control unit 205 performs display control in the order of the surface rendering image and the volume rendering image will be described with reference to FIG. To do. FIG. 5 is an example of a rendered image displayed on the display device 110.

  In this case, the nerve fiber 501 existing inside the living tissue 502 is accurately displayed on the display device 110 inside the living tissue 502. Further, an image of the biological tissue 502 having a predetermined opacity is superimposed on the image of the nerve fiber 501 on the display device 110. By the display control, superimposed display with high visibility can be performed regardless of the opacity value set in each voxel of the three-dimensional volume data. Next, rendering image display control according to the present embodiment will be described with reference to FIG. In the following description, it is assumed that the line-of-sight direction of the three-dimensional display is designated in advance by the user for ease of explanation.

In step S <b> 601, the surface rendering image generation unit 202 of the medical image processing apparatus 100 executes surface rendering image generation processing based on the three-dimensional data of nerve fibers. In the process of S601, the surface rendering image generation unit 202 generates a surface rendering image capable of stereoscopically viewing nerve fibers from the line-of-sight direction designated by the user by the surface rendering method. For example, the surface rendering image generation unit 202 may assign eigenvalues of the diffusion tensor to the three primary colors of RBG and set the surface color of the nerve fiber. Alternatively, the surface rendering image generation unit 202 may arrange the color so as to be red as the ADC or FA value increases, and set the surface color of the nerve fiber. When the processing of S601 ends, the medical image processing apparatus 100 proceeds to volume rendering image generation processing (S602).
In step S <b> 602, the volume rendering image generation unit 203 of the medical image processing apparatus 100 generates a volume rendering image that allows stereoscopic viewing of the living tissue from the line-of-sight direction specified by the user. When the process of S602 ends, the medical image processing apparatus 100 proceeds to the superimposition position calculation process (S603).

  In S603, the observation image generation unit 14 determines, for each voxel, a superposition position between the surface rendering image of the nerve fiber obtained in the process of S601 and the image obtained in the process of S602. Details of the processing of S603 will be described later with reference to FIG. When the processing of S603 ends, the process proceeds to display control processing of the surface rendering image (S604).

  In step S604, the display control unit 205 of the medical image processing apparatus 100 causes the display device 110 to display the surface rendering image generated in step S601 at the position determined in step S603.

  In step S605, the display control unit 205 of the medical image processing apparatus 100 causes the display device 110 to display the volume rendering image generated in the process of S602 at the position determined in the process of S603.

  Next, the overlapping position determination process shown in FIG. 6 will be described in detail with reference to FIG.

  In S701, the depth information acquisition unit 204 acquires depth information (first depth information) of the three-dimensional volume data.

  In step S702, the display control unit 205 determines the display position of the surface rendering image based on the first depth information. Specifically, the display control unit 205 compares the depth information of each voxel value in the three-dimensional data of nerve fibers with the first depth information. The display control unit 205 determines whether to display each voxel of the surface rendering image on the display device 110 based on the comparison result. The display control unit 205 determines to display the voxel of the surface rendering image when the depth direction coordinate of each voxel of the surface rendering image is larger than the first depth information. In other words, the display control unit 205 determines to display the voxel of the surface rendering image when it is determined to be closer to the first depth information when viewed from the predetermined viewpoint position.

  In S703, the depth information acquisition unit 204 acquires depth information (second depth information) of the surface rendering image.

  In step S704, the display control unit 205 determines the display position of the volume rendering image using the second depth information. Specifically, the display control unit 205 compares the second depth information with the three-dimensional position of each voxel of the three-dimensional volume data. The display control unit 205 determines whether to display each voxel of the volume rendering image on the surface rendering image on the display device 110 based on the comparison result. The display control unit 205 determines that the voxels of the volume rendering image are to be superimposed and displayed when the coordinates in the depth direction of each voxel of the volume rendering image are larger than the second depth information. In other words, it can be said that the display control unit 205 superimposes and displays the voxel of the volume rendering image when it is determined that it is in front of the surface rendering image when viewed from the predetermined viewpoint position.

  In S602, the volume rendering image generation unit 203 may generate a volume rendering image based on the three-dimensional volume data on the near side of the second depth information. In other words, the volume rendering image generation unit 203 generates a volume rendering image without using the three-dimensional volume data on the back side of the second depth information. In this case, the volume rendering image generation process can be performed at higher speed.

  In the present embodiment, nerve fibers existing inside the three-dimensional volume data are visualized as three-dimensional data, but the present invention is not limited to this. For example, the present invention can be widely applied to the case where three-dimensional data that has not been captured with the three-dimensional volume data of a CT apparatus or MRI apparatus is superimposed and expressed as a surface rendering image. For example, the medical image processing apparatus 100 may superimpose and display a stent as a surface rendering image on a blood vessel image when displaying a moving image when a stent is inserted into a blood vessel. Alternatively, the medical image processing apparatus 100 may superimpose and display the bypass as a surface rendering image on the heart image as a simulation of the heart bypass operation. Alternatively, the medical image processing apparatus 100 may superimpose and display the blood flow motion as a surface rendering image on the blood vessel when simulating the blood flow motion. The medical image processing apparatus 100 may apply this processing when simulating blood flow movement with respect to a blood vessel in the field of view of an endoscopic image. In this case, the display control unit 205 may switch control based on the type of three-dimensional volume data rendered by each of the volume rendering image generation unit 203 and the surface rendering image generation unit 202.

  That is, the display control unit 205 may perform control so as to switch between the surface rendering image and the volume rendering image to be displayed first according to a predetermined condition.

  The switching control of the display order of the surface rendering image and the volume rendering image will be described with reference to FIG.

  In step S <b> 801, the medical image processing apparatus 100 acquires display conditions for a three-dimensional medical image. In this case, the medical image processing apparatus 100 functions as a condition acquisition unit that acquires display conditions for a three-dimensional medical image. The function is recorded in the external memory 111 and is executed by the CPU 101 by being loaded into the RAM 103 as necessary. The condition acquisition unit acquires a display mode as a display condition. The display mode is input by the input device 109. Here, a plurality of display modes can be set in advance as the display mode. Each display mode is associated with information indicating which of the surface rendering image and the volume rendering image is to be displayed first. As an example, if the display mode is a mode for visualizing the above-described MRI nerve fiber, a volume rendering image is displayed after the surface rendering image is displayed (hereinafter referred to as a first display mode). On the other hand, when the display mode is to display the stent as a surface rendering image superimposed on the above-described blood vessel image, the surface rendering image is displayed after the volume rendering image is displayed (hereinafter referred to as the second display). mode). That is, the medical image processing apparatus 100 selectively switches the display order so that a rendering image that should originally be in front is viewed from the user's line of sight based on the display mode. Therefore, the medical image processing apparatus 100 can switch the display order by the display control unit 205 based on the display mode acquired by the condition acquisition unit.

  Next, the medical image processing apparatus 100 executes the processing from S802 to S804. Note that steps S802 to S804 correspond to steps S601 to S603 in FIG.

  In step S805, the medical image processing apparatus 100 determines which of the surface rendering image and the volume rendering image is in front based on the acquired display condition. When the acquired display mode is the first display mode, the medical image processing apparatus 100 determines that the volume rendering image is in front, and executes the processes of S806 and S807. On the other hand, when the acquired display mode is the second display mode, the medical image processing apparatus 100 determines that the surface rendering image is in front and executes the processes of S808 and S809. Note that when displaying in the second display mode, the medical image processing apparatus 100 may set and display a predetermined opacity for the surface rendering image.

  As described above, the medical image processing apparatus according to the present embodiment can improve the visibility when an image rendered by a different rendering method is superimposed and displayed.

  Each embodiment can also be realized by a computer or a control computer executing a program (computer program). Further, means for supplying a program to a computer, for example, a computer-readable recording medium such as a CD-ROM recording such a program, or a transmission medium such as the Internet for transmitting such a program can also be applied as an embodiment. . The above program can also be applied as an embodiment. The above program, recording medium, transmission medium, and program product are included in the scope of the present invention.

  As mentioned above, although it explained in full detail based on embodiment, it is not restricted to these specific embodiment, Various forms of the range which does not deviate from the summary of invention are also included in the category of this invention. Furthermore, the above-described embodiment is merely an embodiment, and an invention that can be easily imagined from the above-described embodiment is also included in the scope of the present invention.

DESCRIPTION OF SYMBOLS 100 Medical image processing apparatus 201 Image input part 202 Surface rendering image generation part 203 Volume rendering image generation part 204 Depth information acquisition part 205 Display control part

Claims (11)

An image input unit for inputting three-dimensional volume data imaged by a medical image imaging device;
Volume rendering means for generating a volume rendering image based on the three-dimensional volume data input to the image input unit;
A surface rendering means for generating a surface rendering image based on the three-dimensional data;
Depth information acquisition means for acquiring depth information indicating a length from a predetermined viewpoint position in a three-dimensional space to the three-dimensional volume data;
Display control means for displaying the volume rendering image superimposed on the surface rendering image after displaying the surface rendering image based on the depth information acquired by the depth information acquisition means;
A medical image processing apparatus comprising:   The display control unit displays each voxel of the surface rendering image based on a result of comparing the depth information and the depth information of each voxel value in the three-dimensional data used for generation of the surface rendering means. The medical image processing apparatus according to claim 1, wherein:   The surface rendering image is obtained by tracking the extending direction of nerve fibers based on the diffusion anisotropy obtained by the diffusion tensor image generated using the three-dimensional volume data input to the image input unit. The medical image processing apparatus according to claim 1, wherein the medical image processing apparatus is an image generated based on three-dimensional data in which the nerve fibers visualized.   The medical image according to any one of claims 1 to 3, wherein the depth information acquisition unit acquires second depth information for a three-dimensional position of the surface rendering image from the predetermined viewpoint position. Processing equipment.   The display control unit displays the surface rendering image based on the depth information acquired by the depth information acquisition unit, and then displays the volume rendering based on the second depth information acquired by the depth information acquisition unit. The medical image processing apparatus according to claim 4, wherein an image is superimposed and displayed on the surface rendering image.   The medical image processing apparatus according to claim 4, wherein the volume rendering unit generates a volume rendering image based on three-dimensional volume data closer to the second depth information.   The medical image processing apparatus according to claim 6, wherein the volume rendering unit generates a volume rendering image without using three-dimensional volume data at a depth side of the second depth information.   The depth information acquisition unit acquires, as the depth information, a length from the predetermined viewpoint position to a voxel having an opacity greater than a predetermined value among voxels of the three-dimensional volume data. Item 8. The medical image processing apparatus according to any one of Items 1 to 7.   The display control means determines which of the surface rendering image and the volume rendering image is to be displayed first based on the type of three-dimensional volume data to be rendered by each of the volume rendering means and the surface rendering means. The medical image processing apparatus according to claim 1, wherein the medical image processing apparatus is switched. A method for controlling a medical image processing apparatus, comprising:
An image input process for inputting the three-dimensional volume data imaged by the medical imaging apparatus;
A volume rendering step for generating a volume rendering image based on the three-dimensional volume data input to the image input unit;
A surface rendering process for generating a surface rendering image;
A depth information acquisition step for acquiring depth information indicating a length from a predetermined viewpoint position in the three-dimensional space to the three-dimensional volume data based on the three-dimensional volume data;
A display control step of displaying the volume rendering image superimposed on the surface rendering image after displaying the surface rendering image based on the depth information acquired by the depth information acquisition means;
A control method for a medical image processing apparatus, comprising: Medical image processing device
An image input unit for inputting three-dimensional volume data imaged by a medical image imaging device;
Volume rendering means for generating a volume rendering image based on the three-dimensional volume data input to the image input unit;
A surface rendering means for generating a surface rendering image;
Depth information acquisition means for acquiring depth information indicating a length from a predetermined viewpoint position in the three-dimensional space to the three-dimensional volume data based on the three-dimensional volume data;
Display control means for displaying the volume rendering image superimposed on the surface rendering image after displaying the surface rendering image based on the depth information acquired by the depth information acquisition means;
A program characterized by making it function.

Images