JP4767782B2 - Medical imaging device - Google Patents

Description

  The present invention relates to a medical imaging apparatus, and more particularly to a medical imaging apparatus that deforms an organ shown in a tomographic image.

  Supports surgery, diagnosis, etc. by displaying 3D images of the organ of the subject using the image of the subject taken by a medical imaging device such as an X-ray CT device, MR device, ultrasonic imaging device, etc. The device is used.

  However, when the organ is touched by hand or taken out of the body during surgery, the organ is deformed, and the state of the organ is different from the state of the three-dimensional image of the organ displayed on the medical imaging device. .

In order to cope with this, a method for defining a deformation of an organ from two image data at different times and defining the deformation in a three-dimensional space using a weighting function defined for each point in the space. And an apparatus are disclosed.
JP 2003-135438 A

  However, the above-mentioned Patent Document 1 does not consider the following technical problems. Patent Document 1 is a method for obtaining a three-dimensional deformation of an organ that can be deformed over time, and does not obtain a natural deformation of the organ in consideration of gravity. In addition, since two or more pieces of data that can recognize the deformation of the organ are necessary, the deformation of the organ when the organ is touched by hand or the organ is taken out of the body is obtained without actually obtaining the data. It is not possible.

  For example, FIG. 11 (a) shows a case where the liver is inside the body, but when it is outside the body, it is generally deformed by gravity as shown in FIG. 11 (b). FIG. 12 is an image made immediately before the liver transplantation operation and used for examining how to cut the transplanted liver, etc., but considering deformation due to gravity when it is taken out of the body for cutting. Therefore, more accurate surgical simulation information was desired.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a medical imaging apparatus capable of obtaining an image (preferably a three-dimensional image) of an organ deformed by gravity.

In order to solve the above problems, a medical imaging apparatus according to the present invention includes an image acquisition unit that acquires a plurality of tomographic images including an organ region of a subject, and a plurality of tomographic images acquired by the image acquisition unit. and organ extracting means for extracting an organ region, wherein the dividing axis setting means for setting a dividing axis as a reference for dividing the extracted organ region into a plurality of divided surfaces, the divided shaft passing Ru multiple divide A cross-sectional image creating means for creating a first cross-sectional image of the extracted organ region on a surface; and a second cross-sectional image under the influence of gravity of the first cross-sectional image created by the cross-sectional image creating means. A cross-sectional image deforming unit that deforms the display image, a display image creating unit that creates a desired display image based on a plurality of second cross-sectional images deformed by the cross-sectional image deforming unit, and a display image creating unit Display to display the displayed image Is characterized by comprising: a stage, a. According to the above medical imaging apparatus, the organ region of the subject is deformed by gravity on a plurality of division planes passing through the division axis parallel to the direction of gravity, and the organ region of the subject is deformed by gravity based on the deformation. Display the image. Thereby, an image of an organ deformed by gravity can be obtained without obtaining data of the deformed organ.

The medical imaging apparatus of the present invention, the pre-Symbol sectional image deforming means, bending by gravity, displacement, bulging at least one variant the second cross-sectional image by deforming the first sectional image in the form of It is desirable to create. According to the above medical imaging apparatus, the deformation of the organ region of the subject due to gravity depends on at least one of deformation forms of bending, displacement, and swelling. Thereby, the deformation | transformation of the organ by gravity can be expressed appropriately. Note that the bending due to gravity is a deformation mode in which a line in the organ region is rotated at a deformation angle calculated based on a predetermined deformation coefficient that varies depending on the CT value, and the displacement due to the gravity varies depending on the CT value. In this deformation mode, a point in the organ region is moved so as to slide down in the weight direction with a displacement calculated based on the deformation coefficient of the gravity, and the bulge due to gravity is calculated based on a predetermined deformation coefficient that differs depending on the CT value. This is a modification in which the organ region is deformed in the lateral direction so that the areas of the organ region are equal to each other.

The medical imaging apparatus of the present invention, prior Symbol display image generating means uses a plurality of parallel sectional image created from said plurality of second cross-sectional images, or using the plurality of second cross-sectional images It is desirable to directly create a three-dimensional image and use this three-dimensional image as a display image. According to the above medical imaging apparatus, the image of the organ region of the subject after deformation due to gravity is a three-dimensional image, and the three-dimensional image is a plurality of parallel sectional images created from a plurality of second sectional images. Or directly using a plurality of second cross-sectional images. This makes it possible to obtain an image of an organ deformed by gravity that allows direct and easy three-dimensional recognition.

  According to the present invention, it is possible to provide a medical imaging apparatus that can obtain an image (preferably a three-dimensional image) of an organ deformed by gravity.

  The best mode for carrying out the present invention will be described below with reference to the accompanying drawings.

  FIG. 1 is a hardware configuration diagram showing the overall configuration of the medical image apparatus according to the first embodiment of the present invention.

  The medical imaging apparatus 10 is connected to a medical image capturing apparatus 2 that captures an image of a subject via a network such as a LAN 3. Although the X-ray CT apparatus is described as an example of the medical image photographing apparatus, the medical image photographing apparatus is configured by an apparatus capable of photographing a subject image (preferably a three-dimensional image) such as an MR apparatus or an ultrasonic imaging apparatus.

  The medical imaging apparatus 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. , An operating system (OS), a peripheral device drive, a magnetic disk 13 that stores various application software including programs for measuring the thickness of the chest wall, and a display that temporarily stores 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 17 as a position input device, and a mouse on the monitor 15 by detecting the state of the mouse 17 A controller 16 for outputting signals such as the position of the pointer and the state of the mouse 17 to the CPU 11; User and a keyboard 18 for inputting the support, and a bus 19 which connects the above components.

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

  In this embodiment, the magnetic disk 13 is connected as a storage device other than the main memory 12, but a hard disk drive or the like may be connected in addition thereto.

  Next, a processing flow of the medical image device 10 will be described.

  FIG. 2 is a flowchart showing the flow of processing of the medical image device 10. The CPU 11 operates according to this flowchart. The following processing is started after image data (a plurality of tomographic images such as an axial image) obtained by imaging an organ region of a subject is read from the medical image photographing apparatus 2 to the medical image apparatus 10.

  In step S10, an organ region is extracted from a plurality of image data input from the medical image photographing apparatus 2. A plurality of tomographic images A shown in FIG. 3A are images after extraction of organ regions (binary images). The organ C is recognized by the plurality of tomographic images A.

  In step S12, the division axis L is set as shown in FIG. The division axis L can be set at an arbitrary position and angle with respect to the organ C. In general, the division axis L is set so as to pass through a supporting object on which the organ C is placed when the organ C is extracted from the subject. Further, when the organ C is held in the hand, it is set so as to pass through the hand.

  In FIG. 3A, for easy recognition, the division axis L set at an arbitrary position and angle with respect to the organ is arranged in a direction parallel to the gravity direction (vertical downward).

  Next, a method for creating a cross-sectional image Cn (n = 1 to N) from a plurality of tomographic images A will be described (steps S14 to S28).

  In step S14, n = 1 is set.

In step S16, it sets the passing Ru split plane Bn (n = 1~N) split shaft L. In FIG. 3A, since the division axis L is set so as to pass through the inside of the organ C, the division plane Bn (n = 1 to N) is set radially about the division axis L. The dividing plane Bn is set as B1, B2,..., Bn in order clockwise from the dividing plane B1, and makes one round around the dividing axis L.

  In step S18, n = n + 1 is set.

  In step S20, it is determined whether n = N, that is, whether all the divided surfaces Bn (n = 1 to N) have been created. If yes, then continue with step S22, otherwise, return to step S16.

  In step S22, n = 1 is set.

  In step S24, a cross-sectional image Cn (n = 1 to N) of the organ C is created by interpolation calculation on the dividing plane Bn (n = 1 to N). As shown in FIG. 3B, the cross-sectional image of the organ C on the dividing plane B1 is a cross-sectional image C1. Note that various known interpolation methods can be used for the interpolation calculation.

  In step S26, n = n + 1 is set.

  In step S28, it is determined whether or not n = N, that is, whether or not the cross-sectional images Cn (n = 1 to N) have been created for all the divided surfaces Bn (n = 1 to N). If yes, then continue with step S30, otherwise, return to step S24.

  Thereby, the cross-sectional images C1-CN are created with respect to the dividing surfaces B1-BN.

  Next, a method of creating a cross-sectional image Cn ′ (n = 1 to N) that is affected by gravity from the cross-sectional image Cn (n = 1 to N) will be described (steps S30 to S36).

  In step S30, n = 1 is set.

  In step S32, the cross-sectional image Cn (n = 1 to N) is transformed into a cross-sectional image Cn ′ (n = 1 to N) of the organ deformed by gravity (see FIG. 3C). There are three types of deformation methods (deformation modes): bending, misalignment, and bulging, and the deformation is performed by at least one of the above three types of deformation modes. Which deformation mode is used for the deformation is determined by the shape, type, state, etc. of the organ. In the case of FIG.3 (c), the organ C is a liver and a deformation | transformation is performed by two types of deformation forms, a bending and a swelling.

  When the organ C is placed on the support object, the gravity deformation of the part placed on the support object can be ignored, so the nonlinear region is set according to the shape of the support object. When a supporting object is placed as shown in FIG. 4A, a non-deformation region is set above the supporting object as shown in FIG. 4B. When the non-deformation region is set, the region is deformed by at least one deformation mode among bending, misalignment, and bulge in the region (deformation region) other than the non-deformation region. In the above description, the case where the organ C is placed on the supporting object has been described, but the same applies to the case where the organ C is held in the hand. In the case where the organ C is placed on the support object and the part that is not placed on the support object of the organ C is held by hand, the part placed on the support object of the organ C and the part held by the hand May be set as a non-deformation region.

  In step S34, n = n + 1 is set.

  In step S36, whether or not n = N, that is, the cross-sectional image Cn (n = 1 to N) is the cross-sectional image Cn ′ (n = 1 to N) with respect to all the divided surfaces Bn (n = 1 to N). It is determined whether or not it has been deformed. If yes, then continue with step S30, otherwise, return to step S24.

  As a result, cross-sectional images C1 'to CN' that are affected by gravity are generated on the cross-sectional images C1 to CN.

  Next, a method of creating a three-dimensional image that is a display image to be displayed on the monitor 15 using the cross-sectional image Cn ′ (n = 1 to N) affected by gravity will be described.

  In step S38, a plurality of tomographic images A ′ are created from the deformed cross-sectional images Cn ′ (n = 1 to N) by interpolation (see FIG. 3D). This tomographic image A ′ may or may not be parallel to the tomographic image A. Note that various known interpolation methods can be used for the interpolation calculation.

  In step S40, a three-dimensional image of the organ C is created using the tomographic image A '.

  Thereby, a three-dimensional image which is a display image to be displayed on the monitor 15 is created. Note that step S30 can be omitted. If YES in step S28, the calculation time is extra, but a three-dimensional image may be created directly from the cross-sectional image Cn ′ (n = 1 to N).

  The three-dimensional image created in this way is displayed on the monitor as shown in FIG.

  Next, details of the three types of deformation modes, that is, bending, misalignment, and bulging will be described.

  Bending is a deformation form in which, at a certain point p on the cross-sectional image D1 before deformation, the line p1 rotates by an angle θ about the point p and moves to the line p2 (see FIG. 4B). . In the bending deformation mode, the angle θ is a deformation angle, and this deformation angle is calculated based on a deformation coefficient set to a predetermined value depending on the shape, type, state, etc. of the organ. For example, since the deformation coefficient is different between the cancer region and the other region, the deformation angle is different between the case where there is a cancer region (see FIG. 4C) and the case where there is no cancer region (see FIG. 4B). . That is, when the sectional views D1 and E1 before deformation are the same, the sectional view D1 after deformation when there is no cancer region and the image E1 after deformation when there is a cancer region are different. When there is a cancer region, the CT value is different from that when there is no cancer region. Therefore, as shown in FIG. 5, it is easy to understand that it is convenient to provide the deformation coefficient corresponding to the CT value. In the above description, the deformation coefficient varies depending on the CT value. The bending deformation mode has been described as an example. However, in all deformation modes including the following deviation and bulge, the deformation coefficient varies depending on the CT value. Further, the relationship between the CT value and the deformation coefficient is not limited to the example shown in FIG.

The shift is a deformation form in which a distance α moves so as to slide down in the direction of gravity in a certain qn on the cross-sectional image F1 before deformation (see FIG. 6C). 6A shows the organ F before deformation, FIG. 6B shows a cross-sectional image F1 of the organ F on the dividing plane B1, and FIG. FIG. 6 (d) shows the deformed organ F ′. FIG. 6 shows an example in which a deformed part is extracted only by the deformation form of the deviation of the organ D (for example, breast). Since a part of the organ D is extracted, it is assumed that the division axis L is at infinity. Therefore, as shown in FIG. 6A, the dividing surfaces Bn (n = 1 to N) are parallel. In the displacement deformation mode, the distance α is a displacement, and this displacement is calculated based on a deformation coefficient determined to a predetermined value depending on the shape, type, state, etc. of the organ. A bulge is a vertical force due to gravity. This is a deformation mode in which the organ moves so as to deform in the lateral direction (see FIG. 7C). FIG. 7A shows the organ G before deformation, FIG. 7B shows a cross-sectional image G1 of the organ G on the dividing plane B1, and FIG. 7C shows a deformed form in which the cross-sectional image G1 is swollen. FIG. 7 (d) shows the deformed organ G ′. The deformation amount β in the horizontal direction is determined so that the volume of the organ G before deformation and the volume of the organ G ′ after deformation, that is, the area of the cross-sectional image G1 before deformation and the area of the cross-sectional image G1 ′ after deformation are equal. The In the deformation form of the bulge, the deformation amount β is a displacement, and this displacement is calculated based on a deformation coefficient set to a predetermined value depending on the shape, type, state, etc. of the organ.

  Note that, as shown in FIG. 5, the above-described deformation mode and deformation coefficient can be set, changed, and selected by being displayed on the monitor 15 and supported by the operator with the mouse 17 or the like.

  FIG. 8 is an explanatory diagram in which a deformed image is displayed on the monitor 15 in the medical imaging apparatus 10. A three-dimensional image of the deformed organ is displayed on the left side of the monitor 15, and a cross-sectional image of the cut surface when the three-dimensional image is cut at an arbitrary position is displayed on the right side. The position, direction, etc. of the cut surface can be arbitrarily set by the operator using the mouse 17 or the like.

  According to the present embodiment, an image of an organ deformed by gravity can be obtained without obtaining data of the deformed organ. In addition, since deformation is performed by one of bending, displacement, and bulging, or a method that variously combines bending, displacement, and bulging, deformation of the organ due to gravity can be appropriately expressed. In addition, by displaying the shape of the organ deformed by gravity as a three-dimensional image, it is possible to obtain an image of the organ deformed by gravity that can be directly and easily recognized in three dimensions.

  In the present embodiment, one division axis for dividing the division plane for deforming an organ is set, but a plurality of division axes may be set as shown in FIG. FIG. 9 is an explanatory diagram showing a method of deforming an organ having a shape in which two spherical objects are connected by a thin cylindrical object. As shown in FIG. 9A, first, the whole organ (H, I, J) is deformed using the split axis 1. As a result, the shape (H ′, I ′, J ′) as shown in FIG. After that, when only J ′ is deformed around the dividing axis 2, the shape (H ′, I ′, J ″) as shown in FIG. 9C is obtained. In this way, by setting a plurality of division axes in accordance with the shape of the organ, the deformation of the organ due to gravity can be expressed more appropriately.

  Further, in the present embodiment, the division axis is set as shown in FIG. 3, but the division axis can be set at various positions and angles including the position shown in FIG. Note that the position and angle of the split axis can be arbitrarily set by the operator with the mouse 17 or the like while checking the monitor 15 not only before the deformation of the organ but also after the deformation.

1 is a schematic diagram illustrating an overall configuration of a first embodiment of a medical imaging apparatus to which the present invention is applied. It is a flowchart which shows the flow of a process of 1st Embodiment of the said medical imaging device. It is explanatory drawing explaining the method to deform | transform an organ into the shape which received the influence of gravity in 1st Embodiment of the said medical imaging device, (a) shows the setting method of a dividing axis and a dividing surface, (b ) Shows a cross-sectional image at a predetermined dividing plane, (c) shows a state where the cross-sectional image shown in (b) is transformed into a cross-sectional image affected by gravity, and (d) shows a state after being deformed by gravity. Showing organs. It is explanatory drawing explaining the method to deform | transform an organ into the shape which received the influence of gravity by the deformation | transformation form of bending in 1st Embodiment of the said medical imaging device, (a) installs an organ on a support object (B) shows a cross-sectional image at a predetermined dividing plane and a state where the cross-sectional image is transformed into a cross-sectional image affected by gravity, and (c) shows a cancer region in the organ. In this case, a state in which a cross-sectional image at a predetermined dividing surface is transformed into a cross-sectional image affected by gravity is shown. It is explanatory drawing by having displayed on the screen what assigned the deformation coefficient to CT value of 1st Embodiment of the said medical imaging device. It is explanatory drawing explaining the method to deform | transform an organ into the shape which received the influence of gravity by the deformation | transformation form of deviation in 1st Embodiment of the said medical imaging device, (a) is the setting method of a division | segmentation axis and a division | segmentation surface (B) shows a cross-sectional image at a predetermined dividing plane, (c) shows a state where the cross-sectional image shown in (b) is transformed into a cross-sectional image affected by gravity, and (d) shows gravity. The organ after being deformed by is shown. It is explanatory drawing explaining the method to deform | transform an organ into the shape which received the influence of gravity by the deformation | transformation form of the bulge in 1st Embodiment of the said medical imaging device, (a) is a split axis and the setting method of a split surface (B) shows a cross-sectional image at a predetermined dividing plane, (c) shows a state where the cross-sectional image shown in (b) is transformed into a cross-sectional image affected by gravity, and (d) shows gravity. The organ after being deformed by is shown. It is an example of a display of the screen of a 1st embodiment of the above-mentioned medical imaging device. It is explanatory drawing explaining the method to deform | transform an organ into the shape of the organ which received the influence of gravity using the some division | segmentation axis | shaft in 1st Embodiment of the said medical imaging device, (a) is the division | segmentation axis | shaft 1. The case where the organ is deformed by the dividing axis 1 is shown, and (b) shows the case where the organ is deformed by the dividing axis 2. It is explanatory drawing explaining the method to deform | transform an organ into the shape of the organ which received the influence of gravity in 1st Embodiment of the said medical imaging device. It is a three-dimensional image of an organ, (a) shows the case where the organ is inside the body (before deformation), and (b) shows the case where the organ is outside the body (after deformation). It is a display example of the screen of the conventional embodiment.

Explanation of symbols

10: Medical imaging device, 15: Monitor

Claims (6)

Image acquisition means for acquiring a plurality of tomographic images including the organ region of the subject;
Organ extraction means for extracting an organ region from a plurality of tomographic images acquired by the image acquisition means;
A split axis setting means for setting a split axis serving as a reference for dividing the extracted organ region into a plurality of split planes;
And a cross-sectional image generation means for generating a first cross-sectional image of the extracted organ region on the dividing axis passing Ru multiple split plane,
A cross-sectional image deforming means for deforming the first cross-sectional image created by the cross-sectional image creating means into a second cross-sectional image affected by gravity;
Display image creating means for creating a desired display image based on a plurality of second cross-sectional images deformed by the cross-sectional image deforming means;
Display means for displaying the display image created by the display image creating means;
A medical imaging apparatus comprising:   2. The cross-sectional image deforming unit generates the second cross-sectional image by deforming the first cross-sectional image with at least one deformation mode of bending, displacement, and bulging due to gravity. The medical imaging device according to 1.   The display image generation unit directly creates a three-dimensional image using a plurality of parallel cross-sectional images created from the plurality of second cross-sectional images or using the plurality of second cross-sectional images. The medical image apparatus according to claim 1, wherein the dimensional image is a display image.   The medical imaging apparatus according to claim 2, wherein the bending due to gravity is a deformation form in which a line in the organ region is rotated by a deformation angle calculated based on a predetermined deformation coefficient that varies depending on a CT value. .   The displacement due to gravity is a deformation form in which a point in the organ region is moved so as to slide down in a weight direction by a displacement calculated based on a predetermined deformation coefficient that varies depending on a CT value. The medical imaging device described.   The bulge due to gravity is a deformation that is calculated based on a predetermined deformation coefficient that varies depending on a CT value, and is a deformation that deforms the organ region in the lateral direction so that the areas of the organ region are equal. The medical imaging apparatus according to claim 2.

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