JP4738236B2 - Image display device - Google Patents

Description

  The present invention relates to an image display device, and more particularly, to a technique for obtaining a core wire of a luminal organ with higher accuracy.

  Conventionally, as shown in FIG. 11, a core line 112 connecting the center points of each cross section of the luminal organ 111 is obtained from a luminal organ 111 such as a blood vessel captured in a volume image 110 obtained by stacking a plurality of tomographic images. There is a way.

For example, Patent Document 1 discloses a method of leaving only the center line (core line) by repeatedly removing the three-dimensional element closest to the wall surface of the object (luminal organ).
Special table 2001-502197

  However, in Patent Document 1, in order to prevent removal up to the center line (core line) to be obtained, it is necessary to perform a determination operation that the closest three-dimensional element of the wall surface of the object is not the center line, and then remove it. It was a time consuming method. In rare cases, discontinuities may appear on the center line.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an image display device capable of obtaining a core wire with high accuracy by a relatively short time calculation.

  In order to solve the above problems, an image display device according to the present invention obtains a core line of the luminal organ based on a plurality of tomographic images obtained by photographing the luminal organ, and displays an image using the core line. An image display device, wherein the plurality of tomographic images are input, and the luminal organ region in which the luminal organ is imaged for each tomographic image is binarized and extracted to generate a plurality of binary images Binarizing means, a three-dimensional small region centered on one point of the luminal organ region included in the binary image, and another binary image continuous with the binary image including the one point Small area setting means for setting a three-dimensional small area that also includes a hollow organ area, and average coordinates of the hollow organ area included in the small area and central coordinates corresponding to one point that is the center of the small area The coordinate calculation means for obtaining the average coordinates obtained and the small coordinates A distance calculating means for determining a distance from the center coordinate of the area; and comparing the determined distance with a predetermined distance for determining whether or not to use the average coordinate as the coordinate of the core line. If the determined distance is smaller than the predetermined distance, a core line coordinate determination unit that determines that the average coordinate is the coordinate of the core line, a core line generation unit that generates a core line based on the coordinate of the core line, and the core line An image generating means for generating the used image and a display means for displaying an image using the core wire are provided.

  According to the present invention, by determining whether or not the core line is based on the distance between the center coordinates of the small area and the average coordinates of the extraction area included in the small area, the core line has no discontinuous points and is relatively The core line coordinates can be obtained with a short time calculation.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. Note that components having the same function are denoted by the same reference symbols throughout the drawings for describing the embodiment of the invention, and the repetitive description thereof is omitted.

〔System configuration〕
FIG. 1 is a hardware configuration diagram illustrating a configuration of a medical image display system 1 according to the present embodiment.

  A medical image display system 1 in FIG. 1 includes a medical image capturing device 2 that captures an image of a subject, an image database 4 that stores medical images captured by the medical image capturing device 2, and an image that displays an image of the subject. The medical image photographing device 2, the image database (image DB) 4, and the image display device 10 are connected to a network such as a LAN 3. A terminal device 5 for displaying an image generated by the image display device 10, for example, a virtual endoscopic image or a pseudo three-dimensional image, may be connected to the LAN 3.

  The medical imaging apparatus 2 has been described as an X-ray CT apparatus, an MR apparatus, and an ultrasonic imaging apparatus (US apparatus) as an example. However, the medical imaging apparatus 2 is not limited to these as long as it is capable of capturing a tomographic image of a subject. .

  The image display device 10 includes a central processing unit (CPU) 11 as a control device that mainly controls the operation of each component, a main memory 12 that stores a control program for the device, and serves as a work area when the program is executed. , Operating system (OS), peripheral device drive, magnetic disk 13 storing various application software including programs for performing core line extraction processing and image generation processing, which will be described later, and display for temporarily storing display data A memory 14, a monitor 15 such as a CRT monitor or a liquid crystal monitor that displays an image based on data from the display memory 14, a mouse 16 as a position input device, and a mouse on the monitor 15 by detecting the state of the mouse 16 A controller that outputs signals such as the position of the pointer and the state of the mouse 16 to the CPU 11 And 6a, the keyboard 17, a communication interface (hereinafter referred to as "communication I / F") 18, and a bus 19 which connects the above components.

  Next, an image processing program executed by the image display apparatus 10 will be described with reference to FIG. FIG. 2 is a block diagram showing the configuration of the image display program.

  The image display program inputs a volume image (three-dimensional image data) obtained by stacking tomographic images in the body axis direction, and performs binarization processing to extract a target organ for the input volume image. A binary extraction unit 11b, a small region setting unit 11c for setting a small region for extracting a core line, a coordinate calculation unit 11d for obtaining average coordinates of a target organ region and a central coordinate of the small region included in the small region, and the average coordinates The distance calculation unit 11e for determining the distance between the center coordinate and the calculated distance compares the determined distance with a predetermined threshold, determines whether to record the average coordinate and the core line coordinate based on the result, and determines the magnetic disk 13 A core coordinate determination unit 11f that records the coordinates of the core line in a coordinate recording unit 11g made of a recording medium such as the main memory 12 and a core line generation unit 11h that generates a core line based on the recorded coordinates. A pseudo three-dimensional image obtained by superimposing the core line on a pseudo three-dimensional image, or an image based on the core line (for example, a virtual endoscopic image, a curved arbitrary multi-section reconstructed image (hereinafter referred to as a CPR image), a liver resection region (blood vessel) The image generation unit 11i that generates the control region)) and the display control unit 11j that displays these images.

  The CPU 11 of the image display device 10 reads the image program from the magnetic disk 13, loads it into the main memory 12, and executes it.

  The display control unit 11j is not necessarily provided, and the image generated by the CPU 11 may be distributed to the terminal device 5 connected to the LAN 3, and the terminal device 5 may display the image.

[Process flow]
The processing flow of this embodiment will be described with reference to FIG. FIG. 3 is a flowchart showing a processing flow of the present embodiment. In the following processing, the input unit 11a acquires a volume image composed of a plurality of tomographic images from an X-ray CT apparatus, MR apparatus, or US apparatus, or stores a volume image stored in a storage medium such as the image DB 4 or the magnetic disk 13. Reading is started after the binary extraction unit 11b obtains the binary image 3 shown in FIG. 4 by threshold processing or the like. The binary image 3 includes an extraction region A composed of a luminal organ such as a blood vessel region, a bronchial region, or an intestinal region.

  In step S1, a small area for determining whether or not the small area setting unit 11c is a core coordinate is set (S1). This small region is a three-dimensional small region centered on the point (x, y) on the extraction region A. Hereinafter, this point is referred to as a center point, and this coordinate is sometimes referred to as a center coordinate.

  In FIG. 4, cubic small regions B4a and B4b centering on points 41a and 41b on the extraction region A included in the binary images 3-2 and 3-4 are set. The small area B4a also includes the extraction area A included in the binary images 3-1 and 3-3 continuous on the binary image 3-2 including the point 41a. Similarly, the small area B4b includes the extraction area A included in the binary images 3-3 and 3-5 that are continuous on the binary image 3-4 including the point 41b.

  The coordinates of the center points 41a and 41b are (x41a, y41a) and (x41b, y41b), and these coordinates may be recorded in the coordinate recording unit 11g for later processing.

  The shape of the small region may be a cubic body as shown in FIG. 4 or a sphere as shown in FIG. In FIG. 5, spherical small areas B5a and B5b are set around the point 51a (x51a, y51a) and the point 51b (x51b, y51b) on the extraction area A included in the binary images 3-2 and 3-4. To do.

  In step S2, the coordinate calculation unit 11d obtains average coordinates (xav, yav) of the points of the extraction area A included in the small areas Ba and Bb (S2).

  In FIG. 4, points corresponding to the average coordinates (xav1, yav1) and (xav2, yav2) of the small regions B4a and B4b are indicated by 42a and 42b. Similarly, in FIG. 5, the average coordinates of the small regions B5a and B5b are (xav3, yav3) (xav4, yav4), and the corresponding points are indicated by 52a and 52b.

  In step S3, the distance calculation unit 11e obtains a distance l between the center coordinates (x, y) of the small area B and the average coordinates (xav, yav) of the extraction area A included in the small area obtained in step S2. Then, the core coordinate determination unit 11f compares the obtained distance l with a preset constant δ, and the center point (x, y) (for example, 41b) and the average coordinate point (xav, yav) ( For example, it is determined whether or not the distance l between 42b) is smaller than δ (S3).

  It should be noted that the present invention also includes a comparison of the distance l ≦ δ ′ between the center point (x, y) and the average coordinate point (xav, yav) that are simply changed in the way of description.

  If yes, the process proceeds to step S4 (for example, in the case of point 41a or 51a), and if no, the process proceeds to step S5 (for example, in the case of point 41b or 51b).

  In step S4, the core line coordinate determination unit 11f records the average coordinates (xav, yav) in the coordinate recording unit 11g as the coordinates of the core line (S4).

  In step S5, the core coordinate determination unit 11f determines whether or not steps S1 to S4 have been performed for all points (x, y) on the extraction area A. If yes, go to step S6, and if no, step S1. Proceed to

  In step S6, the core wire generation unit 11h reads the coordinates of the core wire from the coordinate recording unit 11g, and generates a core wire (S6).

  In step S7, the image generation unit 11i generates an image based on the core line obtained in step S6, and the display control unit 11j displays it on the monitor 15 (S7).

  6 to 8 show application examples of the core wire extracted as described above. 6 shows a case where a viewpoint 61 is set on the core line 60, a virtual ray is irradiated from the viewpoint 61 onto the inner wall of the luminal organ, and is projected onto the projection plane 62 by using the central projection method. It is a cavity display example.

  FIG. 7 is a diagram illustrating an example of creation and display of CPR. FIG. 7A shows the core wire 60. FIG. 7B schematically shows a process of opening a luminal organ composed of the extraction region A around the core wire 60. FIG. 7C shows a CPR image when the process of FIG. 7B is performed along the curved surface including the core wire 60. FIG. 7D shows a case where a tomographic image (luminal organ) is cut by a curved surface including the core line 60, further shaded, and three-dimensionally displayed.

  FIG. 8 shows an example in which the cut region 85 of the liver 80 is determined. When the mouse 16 clicks and designates a point 81 on the blood vessel of the liver 80 displayed on the monitor 15, the region 85 governed by the blood vessel on the peripheral side (the 82 side) can be determined.

  The display control unit 11j displays these images on the monitor 15.

  FIG. 9 shows an example of a GUI for setting the thickness of the core wire in the above embodiment.

  The screen 90 displays a bar 91 that is a means for specifying the thickness of the core wire, and a thickness display window 92 that displays the thickness specified by the bar 91. When the pointer 91a of the bar 91 is moved to the left, the constant δ used in step S3 is decreased, and is increased when it is moved to the right. When the constant δ is set to a relatively small value (δ = 0, 1, 2, etc.), the core wire becomes thin, and when the constant δ is set to a relatively large value (δ = 3, 4 or a larger value), the core wire becomes thick. In conjunction with this, the thickness of the core 93 displayed in the thickness display window 92 also changes.

  FIG. 10 is an example showing the results of core line extraction according to the prior art and the above embodiment. In FIG. 10, “old” is the result of extracting the core wire according to the prior art, and “new” is the result of extracting the core wire according to the present embodiment. In FIG. 10, the white lines running in the gray extraction area A are the core lines 100 and 101. As is clear when comparing the core lines in the regions marked with ○, the core line 100 according to the conventional technique has some discontinuous points in the core line 100 displayed in white, but the core line 101 according to the present embodiment has discontinuous points. The core wire 101 is continuously displayed up to the erased part.

  As described above, according to the above-described embodiment, the coordinates of the core line are obtained in consideration of the coordinates of the extraction region captured in continuous tomographic images, so that discontinuous points are less likely to be generated in the core line than in the prior art.

Hardware configuration diagram showing the configuration of the medical image display system 1 Program block diagram Flow chart showing the flow of processing of this embodiment Explanation of small area setting (cube) for obtaining average coordinates Explanation of small area setting (sphere) for obtaining average coordinates Example of lumen display by virtual endoscopy when a viewpoint is set on the core line When a tomographic image is cut with a curved surface that includes a core line, and then shaded and displayed in 3D Example of determining the partial area of a specific blood vessel in the liver GUI example for setting the thickness of the core wire Comparison of core line extraction results between the prior art and the present invention Explanatory drawing of the blood vessel region A and the blood vessel core 112 in the tomographic image

Explanation of symbols

1: medical image display system, 2: medical image photographing device, 3: LAN, 4: image DB, 5: terminal device, 10: image display device, 11: CPU, 12: main memory, 13: magnetic disk, 14: Display memory, 15: monitor, 16: mouse, 16a: controller, 17: keyboard, 18: communication I / F, 19: bus

Claims (6)

Based on a plurality of tomographic images taken of a luminal organ, an image display device for obtaining a core line of the luminal organ and displaying an image using the core line,
Input means for inputting the plurality of tomographic images;
Binarizing means for binarizing and extracting a luminal organ region in which the luminal organ is imaged for each tomographic image, and generating a plurality of binary images;
It further includes a three-dimensional small region centered on one point of the hollow organ region included in the binary image, which is a hollow organ region of another binary image continuous to the binary image including the single point. A small area setting means for setting a three-dimensional small area to be
Coordinate calculating means for obtaining an average coordinate of the luminal organ region included in the small region and a central coordinate corresponding to one point which is the center of the small region;
Distance calculating means for determining a distance between the determined average coordinates and the center coordinates of the small area;
The determined distance is compared with a predetermined distance for determining whether or not to use the average coordinates as the coordinates of the core line, and if the determined distance is smaller than the predetermined distance, Core coordinate determination means for determining that the average coordinate is the coordinate of the core,
Core wire generating means for generating a core wire based on the coordinates of the core wire;
Image generating means for generating an image using the core wire;
Display means for displaying an image using the core wire;
An image display device comprising: The image generation means sets a virtual endoscope viewpoint on the generated core line, generates a virtual endoscope image projected onto a projection plane by irradiating a virtual ray from the viewpoint into the lumen organ. And
The display means displays the virtual endoscopic image;
The image display apparatus according to claim 1. The image generation means generates a curved arbitrary multi-section reconstructed image along the traveling direction of the luminal organ based on the generated core line,
The display means displays the curved surface arbitrary multi-section reconstruction image.
The image display apparatus according to claim 1. The luminal organ is a blood vessel that runs in the liver of a subject,
Further comprising designation means for designating a point in any blood vessel in the liver;
The image generating means generates an image indicating a blood vessel dominating region to which blood is supplied from a blood vessel that travels in a peripheral direction from the designated point,
The display means displays an image showing the blood vessel dominating region;
The image display apparatus according to claim 1. A distance setting means for setting the predetermined distance;
The core line generating means generates a thin core line as the set distance is small, and generates a thick core line as the set distance is large.
The image display device according to claim 1, wherein the image display device is an image display device. It further comprises a specifying means for specifying the thickness of the core wire,
The core wire generating means generates the core wire of the specified thickness;
The image display device according to claim 1, wherein the image display device is an image display device.

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