JP3788847B2 - Image processing device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image processing apparatus that extracts a three-dimensional region of interest from a plurality of tomographic image data obtained by various imaging apparatuses such as an X-ray computer (CT) and a magnetic resonance imaging apparatus (MRI).
[0002]
[Prior art]
Conventionally, image processing for reconstructing a plurality of tomographic images from image data obtained by an imaging apparatus such as CT or MRI, extracting a region of interest from each, and creating and displaying a three-dimensional image for the extracted region The device is known. In such a conventional image processing apparatus, only one direction of the subject such as a unidirectional tomographic image (original image) reconstructed on the imaging apparatus side after imaging of the patient or a unidirectional tomographic image obtained by recutting the cross section on the WS side. The three-dimensional region of interest is extracted using a plurality of tomographic images related to the cross section of the image. Therefore, it is very difficult to extract only the region of interest automatically or semi-automatically.
[0003]
[Problems to be solved by the invention]
The present invention has been made in view of such circumstances, and an image processing apparatus capable of accurately and efficiently extracting a three-dimensional region of interest from a plurality of tomographic image data obtained by various modalities. The purpose is to provide.
[0004]
[Means for Solving the Problems]
The image processing apparatus of the present invention extracts a region of interest from the three-dimensional volume data, the image processing apparatus to create and display a three-dimensional image of the region of interest, different first and second cross-section of the subject a section specifying means for specifying a cross-sectional image generating means for generating on the basis of a plurality of cross-sectional images parallel to the volume data to said first plurality of cross-sectional images and the second section parallel to the cross section, said plurality Display means for switching and displaying any one of the cross-sectional images of the first cross-section, and switching and displaying any of the plurality of second cross-sectional images, and the cross-section of the first cross-section displayed by the display means Setting means for setting a first extraction region in the image and setting a second extraction region in the second cross-sectional image; and the first extraction region from a plurality of cross-sectional images parallel to the first cross-section. Including Extracting means for extracting a first region of interest, and extracts the second region of interest including the second extraction region from a plurality of parallel sectional images in the second section, the first from the first region of interest A first three-dimensional image, a second three-dimensional image from the second region of interest, and a logical operation process including a logical product or a logical sum between the first and second three-dimensional images. A creation means for creating a third three-dimensional image, treating tomographic image data obtained from an imaging apparatus such as CT or MR as volume data, performing MPR processing on the volume data, and arbitrarily A cross-sectional image having the same width as that of the volume data is created in the direction (i.e., the cross-sectional direction in which the region can be easily extracted), and region extraction processing is performed on this image.
[0005]
For this reason, it becomes possible to perform region extraction in an arbitrary cross-sectional direction using a cross-sectional image that is easy to perform region extraction. Therefore, the target region of interest can be accurately and efficiently extracted from the tomographic image created under any condition or direction. In addition, since the region of interest and the other regions can be easily divided, the operability related to various image processes can be greatly improved.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram showing a schematic configuration of an image processing apparatus according to an embodiment of the present invention. Reference numeral 1 denotes image data (input data) from which a three-dimensional region of interest is extracted. For example, based on tomographic images Ic having a plurality of cross sections in an arbitrary direction (oblique direction) of the subject as shown in FIG. It is the created volume data. The tomographic image Ic is obtained using an imaging apparatus such as CT or MRI. The image data 1 is recorded on, for example, a magneto-optical disk (Mo) or the like, and is input to the image processing apparatus of this embodiment via such a recording medium. The image data 1 includes data converted and created using a second console or the like (WS).
[0007]
The apparatus includes a cross-sectional position designating unit 2 for designating an arbitrary cross-sectional position, a cross-sectional image creating unit 3 for creating a cross-sectional image of the cross-sectional position designated by the cross-sectional position designating unit 2 from volume data, and a cross-sectional image A region-of-interest setting unit 5 that sets a region of interest on the cross-sectional image created by the creating unit 3 and a plurality of extracted cross-sectional images parallel to the cross-sectional image created by the cross-sectional image creating unit 5 The extracted section automatic creation means 4 for creating only the width, the designated section display means 7 for sequentially switching and displaying a plurality of extracted section images created by the extracted section automatic creation means 4, and the region of interest setting means 5 are set. The extraction area display means 6 for displaying the binary image of the region of interest superimposed on the original image, and the display area of the screen are divided, whereby at least three extraction Region division display means 8 for simultaneously displaying cross-sectional images, extraction area calculation means 9 for performing logical operation processing including logical product or logical sum for each region of interest extracted along each cross-sectional direction, and extracted The monitor 11 includes a three-dimensional image creation / display unit 10 that creates and displays a three-dimensional image from the area.
"Section image and direction"
In this apparatus, the input image data is subjected to so-called cross-section conversion processing in consideration of information such as the imaging direction and image direction of the subject, thereby orthogonal to each coordinate axis of the subject coordinate system. Three types of cross-sectional images, that is, an axial image, a sagittal image, and a coronal image are created. These images are displayed side by side on one screen as shown in FIG. 3, for example. In particular, in the same figure, the sagittal image is displayed in the display area of the A plane, the coronal image is displayed in the display area of the B plane, and the axial image is displayed in the display area of the C plane. . Note that a wavy line A1 in the display area of the A plane in the figure represents the position of the coronal image displayed on the B plane, and a wavy line A2 represents the position of the axial image displayed on the C plane. Further, a wavy line B1 in the display area of the B plane in FIG. 7 represents the position of the sagittal image displayed on the A plane, and a wavy line B2 represents the position of the axial image displayed on the C plane. A wavy line C1 in the display area of the C plane in FIG. 3 represents the position of the sagittal image displayed on the A plane, and a wavy line C2 represents the position of the coronal image displayed on the B plane.
[0008]
The cross-sectional images shown here are cross-sectional images used when performing region extraction, and these images are parallel to the A-side, B-side, and C-side cross-sectional images displayed on the screen. The same width as the data is created. For example, when an image on the C plane (axial image) is considered, the range from the line P1 to the line P2 shown on the A plane in FIG. 3 is the range of the cross-sectional image used for extraction.
[0009]
The images of plane A, plane B, and plane C shown in FIG. 3 are set as cross-sectional images that are orthogonal to each other. The region can be extracted by using these cross-sectional images, but in the present embodiment, it is also possible to use an image cut out in an oblique direction (oblique direction) for extracting the region of interest. Yes. For example, when the region of interest extends obliquely with respect to the body axis as shown in FIG. 4, the line A indicating the cross-sectional position of the C surface is rotated (line A) as shown in the A surface of FIG. Thus, an image in a cross-sectional direction along the region of interest can be used. Incidentally, the range between line B and line C is the range of the cross-sectional image used for region extraction. The cross-sectional image cut in the oblique direction as described above may be displayed in any one of the display areas on the A to C planes, or may be displayed in another display area. In the initial state when the system of the image processing apparatus is activated, axial, sagittal, and coronal are displayed.
"Specifying and Displaying Extraction Area"
In this apparatus, for each of the A surface, the B surface, and the C surface, an independent extraction region can be designated on each surface. The extraction area is designated by various methods as shown below, for example.
(1) Extraction by Specifying the Range of the Gray Value of the Original Image In this method, a required area is extracted by specifying the range of the gray value of the pixels of the original image. For example, in FIG. 6, FIG. 6A shows a grayscale image of the original image. Here, when the range of the gray value of the pixel representing the bone tissue is designated, only the pixel having the gray value (that is, the bone portion) is extracted from the original image as shown in FIG.
(2) Extraction of region of interest by drawing In this method, as shown in FIG. 7, for example, an operator designates a plurality of point sequences using a mouse or the like to draw a line on the original image (FIG. 7A). Minutes are drawn, and the region represented by this line segment is extracted as a region of interest. Note that it is also possible to specify the range by the gray value of (1) only for this region. FIG. 5B shows the extraction result in this case.
(3) Automatic extraction of connected regions First, by specifying a predetermined gray value range, a plurality of cross-sectional images parallel to the display cross-section used for region extraction are binarized. In addition, the range specification of the gray value here can be used in combination with the above range specification by the gray value. Next, one extraction start point is set on the binarized image, and a connected area including this point is automatically searched (extracted). There are two-dimensional mode and three-dimensional mode for automatic search for connected regions.
[0010]
The required area is extracted as described above, and the extraction result is displayed as follows. FIG. 9 is a diagram for explaining how to display the extraction result.
Here, in principle, the extraction result is displayed as a binary image. In this case, the binary image (FIG. (B)) and the original image (FIG. (A), cross-sectional image used for extraction) are switched. Alternatively, the binary image and the original image may be overlapped (overlapped) and displayed ((c) in the figure).
As for the extraction result, the shape can be confirmed on an image other than the used cross-sectional image. For example, extraction is performed on the A plane, and MPR is performed on the result to reflect the result on the B and C plane images.
[0011]
Here, the ratio at which the binary image and the original image overlap may be set as a numerical value, for example, 50% for the binary image and 50% for the original image. In addition, the binary image may be colored so that the binary image and the original image can be distinguished.
"3D imaging and display of extracted regions"
Further, three-dimensional imaging based on the extracted area is performed. The three-dimensional image created here is displayed at the lower right of the screen as shown in FIG. Creation of a three-dimensional image is performed as follows. That is, a region extracted on the A surface, the B surface, or the C surface is used, respectively, and a three-dimensional image of the extracted region for each surface is created. FIG. 11 shows a three-dimensional image created in this manner. In FIG. 11, (a) shows a three-dimensional image of an extraction region (bone) on the A plane, and (b) shows an extraction on the B plane. A three-dimensional image of the region (brain tissue) is shown, and (c) shows a three-dimensional image of the extraction region (tumor tissue) on the C plane.
[0012]
In the present embodiment, it is also possible to create a three-dimensional image based on the logical operation of the extraction regions on each surface. That is, a predetermined area is selected from a plurality of areas extracted on the A plane, the B plane, or the C plane, and logic such as AND (logical product) or OR (logical sum) is selected between the images of the selected individual regions. It is possible to perform a calculation and perform three-dimensional imaging using the calculation result. FIG. 12 shows an example of such three-dimensional imaging. For example, as a result of performing the AND operation between the left and right images in FIG. 9A and performing the three-dimensional imaging, an image as shown in FIG. In addition, as a result of performing an OR operation between the two left and right images in FIG. 4C and performing three-dimensional imaging, an image as shown in FIG.
[0013]
The created three-dimensional image can be displayed by rotating or moving by selecting and dragging with the mouse cursor.
Here, when the mouse cursor is clicked on the three-dimensional image, the position of the clicked point is selected, and the original image (cross-sectional image used for region extraction) corresponding to this position is displayed (see FIG. 13). At this time, a predetermined mark represented by “+” in the figure is displayed on the original image at the same position as the point designated on the three-dimensional image.
[0014]
As described above, according to the present embodiment, tomographic image data obtained from an imaging apparatus such as CT or MR is handled as volume data, MPR processing is performed on the volume data, and an arbitrary direction (region extraction) is performed. A cross-sectional image having the same width as that of the volume data is created in a cross-sectional direction that is easy to perform, and region extraction processing is performed on this image.
[0015]
For this reason, it becomes possible to perform region extraction in an arbitrary cross-sectional direction using a cross-sectional image that is easy to perform region extraction. Therefore, the target region of interest can be accurately and efficiently extracted from the tomographic image created under any condition or direction. In addition, since the region of interest and the other regions can be easily divided, the operability related to various image processes can be greatly improved.
The present invention is not limited to the above-described embodiment, and can be implemented with various modifications.
[0016]
【The invention's effect】
According to the present invention, a target region of interest can be easily extracted from a cross-sectional image photographed or cut out under any conditions. Further, according to the logical operation processing of the extraction area, the extraction accuracy can be improved. Therefore, a highly accurate three-dimensional image can be easily created and displayed.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of an invention.
FIG. 2 is an explanatory diagram related to input data.
FIG. 3 is an explanatory diagram regarding display of a cross-sectional image.
FIG. 4 is an explanatory diagram regarding the shape of a region of interest and the direction of a fault.
FIG. 5 is an explanatory diagram regarding movement and rotation in a cross-sectional direction.
FIG. 6 is an explanatory diagram relating to an extraction method using gray values.
FIG. 7 is an explanatory diagram relating to an extraction method for drawing a line segment in a region of interest.
FIG. 8 is an explanatory diagram relating to an extraction method for tracking connected regions of binary images.
FIG. 9 is an explanatory diagram regarding a display method of extraction results.
FIG. 10 is an explanatory diagram regarding a display position of a three-dimensional image.
FIG. 11 is a first explanatory diagram related to creation and display of a three-dimensional image.
FIG. 12 is a second explanatory diagram related to creation and display of a three-dimensional image.
FIG. 13 is an explanatory diagram related to retrieval and display of a cross-sectional image.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Image data 2 ... Section position designation means 3 ... Section image creation means 4 ... Extraction section automatic creation means 5 ... Region of interest setting means 6 ... Extraction area display means 7 ... Designated section display means 8 ... Area division display means 9 ... Extraction Area calculation means 10 ... 3D image creation and display means 11 ... monitor

Claims (5)

In an image processing apparatus that extracts a three-dimensional region of interest from volume data of a subject and creates a three-dimensional image of the region of interest,
Cross-section designating means for designating different first and second cross-sections of the subject;
Cross-sectional image creating means for creating a plurality of cross-sectional images parallel to the first cross-section and a plurality of cross-sectional images parallel to the second cross-section based on the volume data;
Display means for switching and displaying any one of the plurality of first cross-sectional images, and switching and displaying any of the plurality of second cross-sectional images;
Setting means for setting a first extraction area in the cross-sectional image of the first cross section displayed by the display means, and setting a second extraction area in the second cross-sectional image;
A first region of interest including the first extraction region is extracted from a plurality of cross-sectional images parallel to the first cross-section, and the second extraction region is extracted from a plurality of cross-sectional images parallel to the second cross-section. Extraction means for extracting a second region of interest including :
Creating a first three-dimensional image from the first region of interest, creating a second three-dimensional image from the second region of interest, and a logical product between the first and second three-dimensional images, or Creating means for creating a third three-dimensional image by logical operation processing including logical sum ;
An image processing apparatus comprising: The image processing apparatus according to claim 1 , wherein the cross-sectional image creating unit includes a cross-sectional conversion processing unit that performs cross-sectional conversion processing on a plurality of tomographic images constituting the volume data. The image processing apparatus according to claim 1 , further comprising: an extraction region display unit that binarizes the region of interest extracted by the extraction unit and displays the binarized region on the cross-sectional image. The image processing apparatus according to claim 3 , further comprising means for changing a superposition ratio between the binarized region of interest and the cross-sectional image. The image processing apparatus according to claim 1 , further comprising means for displaying the three-dimensional image created by the creating means and the cross-sectional image side by side.

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