JP2007135843A - Image processor, image processing program and image processing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image processor capable of obtaining the detailed image of a diagnostic part while making it possible to recognize the position relation of the diagnostic part and peripheral tissue. <P>SOLUTION: By performing MIP processing with the inside of a 3DROI 18 as an object for volume data, MIP image data are prepared. For a region other than the 3DROI 18, by performing volume rendering with the region other than the region formed by projecting a 2DROI 15 in a projection direction (the depth direction of a screen 13a) as an object, VR image data are prepared. The MIP image and the VR image are superimposed and displayed at a display part. Since the image is not formed for the regions before and after the MIP image, the detailed image is obtained for a lesion inside the 3DROI 18, and the position relation with the peripheral tissue is recognized by observing the VR image. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an image processing apparatus that performs image processing on image data collected by a medical image diagnostic apparatus such as an X-ray CT apparatus, an MRI apparatus, or an ultrasonic diagnostic apparatus. In particular, the present invention relates to an image processing apparatus for creating image data having three-dimensional information for diagnosing a lesion.

  Conventionally, volume data (voxel data) of a subject is collected using a medical image diagnostic apparatus such as an X-ray CT apparatus, predetermined image processing is performed on the volume data, and the obtained image is referred to. The lesion is diagnosed at.

  For example, volume rendering is known as a representative technique for creating a three-dimensional image. In this volume rendering, a predetermined line-of-sight direction (projection direction of projected light) is determined for volume data, ray-tracing processing is performed from an arbitrary viewpoint, and an integrated value or weight of a voxel value (luminance value, etc.) on the line of sight This is a process for generating volume rendering image data (hereinafter sometimes referred to as “VR image data”) by three-dimensionally extracting an organ or the like by outputting a cumulative addition value to an image pixel on the projection plane. .

  In addition to volume rendering, MPR (Multi Plane Construction) processing, MIP (Maximum Intensity Projection) processing, or MinIP (Minimum Intensity Projection) processing, etc. are performed depending on the application. Hereinafter, image data obtained by MPR processing is referred to as “MPR image data”, image data obtained by MIP processing is referred to as “MIP image data”, and image data obtained by MinIP processing is referred to as “MinIP image data”. I will call it.

  The MPR process is a process for obtaining image data of an arbitrary plane (cut plane) for cutting the volume data. The MIP process is a process of calculating a maximum value from each voxel value penetrated by the projection light and outputting the obtained maximum value to an image pixel on the projection plane. The MinIP process is a process of calculating a minimum value from each voxel value and outputting the obtained minimum value to an image pixel on the projection plane.

  In the diagnosis using the MPR image, there is a case where the MPR image data with thickness is created by adding and averaging a plurality of MPR images in the thickness direction, and the diagnosis is performed with reference to the MPR image with thickness.

  For example, when diagnosing arterial cancer of the aorta using a contrast medium, the CT value range (approximately 200 or more) of blood vessels (aorta) and bones (such as avalan bone and spine) into which a contrast medium has been injected VR image data is created by performing volume rendering with (opacity) set to “1”. Then, the VR image is displayed on the display device, and the positional relationship between the rough shape of the aorta and the tissue (bone) existing in the peripheral region is grasped.

  Next, in order to visually or quantitatively grasp the diameter of the arterial cancer that is the lesion site, the inner diameter of the blood vessel, etc., the MPR image data or MIP image data is subjected to MPR processing or MIP processing on the volume data. And the like, and MPR images and MIP images are displayed on the display device for detailed diagnosis. MIP images and the like reflect CT values and are useful for detailed diagnosis of lesions.

  Although it is useful to use the VR image for grasping the positional relationship between the lesioned part and the surrounding tissue and for roughly grasping the shape, it is generally not used for detailed diagnosis of the lesioned part. This is because a VR image is usually colored and displayed as a color image, and the actual CT value is not reflected in the VR image itself. Further, even if the opacity (opacity) at the time of volume rendering is adjusted, it is difficult to visually determine the distinction between the region of arterial cancer and the inside of the blood vessel. Therefore, when making a detailed diagnosis of a lesion, an MIP image or an MPR image is used, and a VR image is used as an auxiliary image.

  When making a detailed diagnosis, display a thick MPR image or MIP image representing the lesion on a display device, and measure the diameter of the arterial cancer or the inner diameter of the blood vessel on the MPR image or MIP image with thickness. Yes.

  However, in the MIP image, the CT value in the projection direction (corresponding to the depth direction of the screen of the display device) is reflected, and in the MPR image with thickness, information on a predetermined region in the thickness direction is displayed. Only displayed. Therefore, these images are difficult to grasp the positional relationship between the lesioned part and the tissue existing in the peripheral region, and are not suitable for images used for surgical planning.

  Conventionally, when grasping the positional relationship, a VR image is displayed on the display device, and when performing detailed diagnosis of a lesion, the VR image is switched to the MIP image and displayed on the display device. In addition, the VR image and the MIP image are displayed side by side on the display device, thereby grasping the positional relationship and performing detailed diagnosis of the lesion. Furthermore, an attempt is made to synthesize a VR image and an MPR image and display them on a display device (for example, Patent Document 1).

Japanese Patent Laid-Open No. 11-76228

  However, in the above-described conventional image processing, the MIP image and the VR image are displayed side by side or displayed on the display device, so that the detailed diagnosis of the lesioned part and the position of the lesioned part are performed. It was necessary to grasp the relationship while observing images displayed on separate screens. For this reason, a diagnosis person such as a doctor needs to make a diagnosis while organizing the information in his / her head or create an operation plan, so that the diagnosis is not easy. In particular, in the technique according to the prior art, it is difficult to grasp the positional relationship between the lesioned part and the surrounding tissue.

  In addition, when a MIP image is used for diagnosis and there is a bone having a CT value close to the focused lesion, the bone is displayed overlapping the lesion. Observation becomes difficult.

  The present invention solves the above-described problem, an image processing apparatus capable of obtaining a detailed image of a lesioned part, an image processing program, and a grasping of a positional relationship between the lesioned part and surrounding tissue, and An object is to provide an image processing method.

  In the first aspect of the invention, the volume data collected by the medical image diagnostic apparatus is projected onto a projection plane viewed from a viewpoint in a predetermined direction with respect to the volume data collected by the medical image diagnostic apparatus. Regions other than first image creation means for creating image data, the desired three-dimensional region of interest in the volume data, and regions before and after the desired three-dimensional region of interest when viewed from the viewpoint in the predetermined direction Is projected onto the projection plane to produce second 3D image data, an image based on the first 3D image data, and the second 3D image data An image processing apparatus comprising: a display control unit configured to superimpose an image on a display unit.

  According to the thirteenth aspect of the present invention, the first three-dimensional region of interest is projected onto a projection plane viewed from a viewpoint in a predetermined direction on the volume data collected by the medical image diagnostic apparatus. A first image creation function for creating the three-dimensional image data, and excluding the desired three-dimensional region of interest from the volume data, and before and after the desired three-dimensional region of interest when viewed from the viewpoint in the predetermined direction A second image creation function for creating second 3D image data by projecting an area other than the area onto the projection plane, an image based on the first 3D image data, and the second 3D An image processing program for executing a display control function for superimposing an image based on dimensional image data and displaying the image on a display unit.

  According to the fourteenth aspect of the present invention, the first three-dimensional image is projected on the volume data collected by the medical image diagnostic apparatus by projecting a desired three-dimensional region of interest onto a projection plane viewed from a viewpoint in a predetermined direction. A first image creation step for creating image data; and removing the desired three-dimensional region of interest from the volume data and viewing regions before and after the desired three-dimensional region of interest when viewed from the viewpoint in the predetermined direction A second image creating step of creating second 3D image data by projecting a region to be excluded onto the projection plane; an image based on the first 3D image data; and the second 3D image data A display step of superimposing an image based on the image and displaying the image on a display means.

  According to the present invention, a detailed image can be obtained for the lesioned part included in the region of interest, and the positional relationship between the lesioned part and the surrounding tissue can be easily grasped.

[First Embodiment]
The configuration of the image processing apparatus according to the first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a block diagram showing the configuration of the image processing apparatus according to the first embodiment of the present invention.

  The image processing apparatus 1 according to this embodiment performs volume rendering, MPR processing, MIP processing, etc. on volume data collected by a medical image diagnostic apparatus such as an X-ray CT apparatus, an MRI apparatus, or an ultrasonic diagnostic apparatus. To generate VR image data, MIP image data, and the like. The image processing apparatus 1 may be installed in the medical image diagnostic apparatus or may be installed outside the medical image diagnostic apparatus.

  The volume data storage unit 5 stores volume data (voxel data) collected and reconstructed by a medical image diagnostic apparatus such as an X-ray CT apparatus. The image processing apparatus 1 creates desired image data by performing image processing on the volume data stored in the volume data storage unit 5.

  The input unit 2 includes an input device such as a keyboard as a mouse. The operation information input by the input unit 2 is output to the input analysis unit 3.

  The input analysis unit 3 decodes the operation content operated by the input unit 2 and calculates parameters necessary for various processes performed subsequently. For example, when the setting screen is displayed on the display unit 13, the button of the setting screen is pressed with the mouse (input unit 2), or the medical image is displayed on the display unit 13. Is dragged by the mouse (input unit 2), the input analysis unit 3 decodes the operation content by the mouse (input unit 2) and calculates parameters necessary for various processes to be performed subsequently. Here, specific processing by the input analysis unit 2 will be described with reference to FIG. FIG. 2 is a schematic diagram for explaining the positional relationship between the blood vessels, the surrounding tissues (bones), and the display unit screen.

  In the mode for designating the center point of the two-dimensional region of interest (2DROI), a VR image is displayed on the display unit 13. When the mouse (input unit 2) is clicked on the VR image displayed on the display unit 13, the input analysis unit 3 displays the two-dimensional screen coordinate system (orthogonal coordinate system) for the clicked position. ) Is determined, and the coordinates are set as the coordinates of the center point of the 2DROI. For example, as shown in FIG. 2, when a point 14 is designated with the mouse (input unit 2) on the screen 13 a of the display unit 13, the input analysis unit 3 uses the point 14 as a center point of 2DROI to 2 The coordinates in the coordinate system (orthogonal coordinate system) of the dimension screen are obtained. The coordinates of the center point 14 of the 2DROI are output to the ROI information calculation unit 4 and the ROI information storage unit 6 and stored in the ROI information storage unit 6.

  In the mode for designating the shape of the two-dimensional region of interest (2DROI), when the mouse (input unit 2) is dragged on the VR image displayed on the display unit 13, the input analysis unit 3 is dragged. The shape and size of the selected range are set as the shape and size of the 2DROI. As for the size, when the 2DROI shape is a circle, the input analysis unit 3 obtains the radius of the circle, and when the shape is a rectangle, obtains the coordinates of each vertex of the rectangle. For example, as shown in FIG. 2, when the 2DROI 15 is drawn by dragging the mouse (input unit 2) on the screen 13 a of the display unit 13, the input analysis unit 3 obtains the shape and size of the 2DROI 15. . In the example shown in FIG. 2, since the shape of the 2DROI 15 is circular, the input analysis unit 3 obtains the radius of the circle. Information indicating the shape and size of the 2DROI 15 is output to the ROI information calculation unit 4 and the ROI information storage unit 6 and stored in the ROI information storage unit 6.

  In the mode of changing the thickness in the projection direction of the three-dimensional region of interest (3DROI), when the mouse (input unit 2) is dragged on the VR image displayed on the display unit 13, the input analysis unit 3 The thickness according to the amount of movement of the mouse is set as the thickness in the projection direction of the three-dimensional region of interest (3DROI). For example, when changing the thickness of the MPR image with thickness, when the mouse (input unit 2) is dragged on the VR image displayed on the display unit 13, the input analysis unit 3 determines the amount of movement of the mouse. The corresponding thickness is set as a range for creating the MPR image with thickness. Information indicating the thickness of the 3DROI in the projection direction is output to the ROI information calculation unit 4.

  In the mode in which the 2DROI is moved on the screen of the display unit 13, when the mouse (input unit 2) is dragged within the 2DROI 15 displayed on the display unit 13, the input analysis unit 3 displays the coordinate system of the two-dimensional screen. The coordinates of the center point of 2DROI in (orthogonal coordinate system) are obtained. For example, as shown in FIG. 2, when the 2DROI 15 is moved by dragging the mouse (input unit 2) in the 2DROI 15 displayed on the screen 13a of the display unit 13, the input analysis unit 3 is displayed on the two-dimensional screen. The coordinates of the new center point 14 of the 2DROI 15 in the coordinate system are obtained. The coordinates of the new center point 14 are output to the ROI information calculation unit 4 and the ROI information storage unit 6 and stored in the ROI information storage unit 6.

  In the mode in which the VR image displayed on the display unit 13 is rotated and displayed, when the mouse (input unit 2) is dragged on the VR image displayed on the display unit 13, the input analysis unit 3 A rotation matrix of VR image data is obtained. Information indicating a rotation row example is output to and stored in the display condition storage unit 8.

  Alternatively, when the opacity curve displayed on the display unit 13 is dragged with the mouse (input unit 2), the input analysis unit 3 obtains an opacity curve value in volume rendering. The opacity curve value is output to and stored in the VR condition storage unit 7.

  Regarding the change of each mode, a desired mode can be selected by pressing a mode designation button on the setting screen displayed on the display unit 13. Further, when input or processing in a certain mode is completed, the next mode may be automatically executed. Further, a plurality of buttons installed on the mouse (input unit 2) may be combined, execution of each mode may be assigned to a different combination, and each mode may be executed by pressing the button according to the combination. .

  The ROI information calculation unit 4 receives information indicating the coordinates of the center point 14 of the 2DROI and the shape and size of the 2DROI from the input analysis unit 3, and in the volume coordinate system (orthogonal coordinate system) of the three-dimensional region of interest (3DROI). Determine the position and shape and size of the 3DROI. That is, the ROI information calculation unit 4 obtains the position and range of the 3D ROI.

  Processing in the ROI information calculation unit 4 will be described with reference to FIG. FIG. 3 is a schematic diagram for explaining processing for obtaining a range of a three-dimensional region of interest (3DROI). The ROI information calculation unit 4 obtains a 3D ROI range based on an area in which the opacity (opacity) is set to a predetermined value or more (eg, 0.8 or more) in the volume data. Here, it is assumed that an opacity (opacity) greater than or equal to a predetermined value is set for the blood vessel 16 into which the contrast agent has been injected. In addition, an organization in which an opacity (opacity) greater than a predetermined value is set may be referred to as an “opaque organization”.

  The ROI information calculation unit 4 projects the center point 14 of the 2DROI 15 in the projection direction (corresponding to the depth direction of the screen), and the center point P of the opaque tissue (blood vessel 16) existing in the projection direction is the center of the 3DROI. The coordinates of the center point P in the volume coordinate system are obtained as points. That is, the ROI information calculation unit 4 projects the center point 14 of the 2D ROI 15 in the projection direction, and the center point P in the range in which the value of opacity (opacity) existing in the projection direction is set to 0.8 or more, for example. Is the center point of the 3DROI. In the example shown in FIG. 3, the thickness in the range in which the opacity (opacity) is set to 0.8 or more, that is, the thickness of the opaque tissue (blood vessel 16) in the projection direction is defined as the thickness L1.

  Further, the ROI information calculation unit 4 determines the shape and size of the 3D ROI. In the example shown in FIG. 3, the shape of the 3DROI 18 is a cylindrical shape. Since the shape of the 2DROI 15 drawn on the screen 13a of the display unit 13 is a circular shape, a cylindrical shape is formed by projecting the circular 2DROI 15 in the projection direction (the depth direction of the screen). Then, by determining the thickness in the projection direction, the shape and size of the 3DROI 18 are determined. Here, the ROI information calculation unit 4 sets the thickness L2 in the projection direction (depth direction of the screen) of the 3DROI 18 to be equal to or greater than the thickness L1 in the projection direction of the opaque tissue (blood vessel 16). The thickness L2 in the projection direction of the 3DROI 18 can be arbitrarily determined by the operator.

When the ROI information calculation unit 4 automatically determines the thickness L2 in the projection direction of the 3DROI 18, the thickness L2 is obtained by the following equation.
3DROI thickness L2 = thickness L1 × factor k
Here, the coefficient k is a predetermined constant, and for example, a value such as k = 1.5 is used.

  The shape of the 3DROI shown in FIG. 3 is a cylindrical shape, but may be a shape other than a cylindrical shape. For example, when the 2DROI shape drawn on the screen 13a of the display unit 13 is a rectangular shape, the 3DROI shape is a prismatic shape. Further, as shown in the schematic diagram of FIG. 6, the shape of the 3DROI 18A may be spherical. This is the same as the method described above, such as a method for calculating the coordinates of the center of the 3DROI. Since the 3DROI 18A has a spherical shape, the thickness L2 in the projection direction is the diameter of the 3DROI 18A.

  The coordinates of the center point P of the 3DROI 18 obtained as described above, information indicating the shape of the 3DROI, and information indicating the size of the 3DROI are output and stored in the ROI information storage unit 6.

  The ROI information storage unit 6 stores information about the region of interest (ROI) obtained by the input analysis unit 2 and the ROI information calculation unit 4. For example, the coordinates of the 3DROI center point P obtained by the ROI information calculation unit 4 in the volume coordinate system, information indicating the shape of the 3DROI (for example, a cylindrical shape), and information indicating the size of the 3DROI are ROI information. It is stored in the storage unit 6. As information indicating the size of the 3DROI, a thickness L2 in the 3DROI projection direction (the depth direction of the screen) is stored. Further, the coordinates of the center point of the 2DROI obtained by the input analysis unit 2 and information indicating the shape and size of the 2DROI (for example, the radius of the circle in the case of a circular 2DROI) are stored.

  The VR condition storage unit 7 stores an opacity curve value used for volume rendering, which is specified by the input unit 2 and obtained by the input analysis unit 3.

  The display condition storage unit 8 stores a rotation matrix of volume data specified by the input unit 2 and obtained by the input analysis unit 3.

  The 2DROI image data creation unit 9 displays information on the display unit 13 based on information indicating the shape of the 2DROI stored in the ROI information storage unit 6 (for a circular 2DROI, the radius of the circle). Create 2DROI image data.

  The VR image data creation unit 10 reads the volume data designated by the operator from the volume data storage unit 5, and further, the coordinates of the center position of the 3DROI, the information indicating the shape of the 3DROI, and the 3DROI from the ROI information storage unit 6 The VR image data is created by reading the information indicating the size of the image and performing volume rendering on the volume data.

  The VR image data creation unit 10 performs volume rendering for the area excluding the area before and after the 3DROI 18 from the viewpoint of the projection direction (the depth direction of the screen), as well as excluding the area occupied by the 3DROI 18 from the volume data. That is, volume rendering is not performed for volume data included in the 3DROI 18 and volume data existing before and after the 3DROI 18 in the projection direction (depth direction of the screen), and volume rendering is performed for volume data in other areas. Apply. Thus, VR image data that does not include the area occupied by the 3DROI 18 and the areas before and after the 3DROI 18 in the projection direction (the depth direction of the screen) is created. The VR image data creation unit 10 functions as an example of the “second image creation unit” of the present invention. The VR image data is output to the display control unit 12.

  If there is no information related to 3DROI in the ROI information storage unit 6, the VR image data creation unit 10 creates VR image data of the entire volume data by performing volume rendering on the entire volume data.

  The MIP image data creation unit 11 reads the volume data from the volume data storage unit 5, and further receives information indicating the coordinates of the center position of the 3DROI, information indicating the shape of the 3DROI, and information indicating the size of the 3DROI from the ROI information storage unit 6. The MIP image data is created by reading and performing MIP processing on the volume data existing in the 3DROI. The MIP image data creation unit 11 functions as an example of the “first image creation unit” of the present invention. The MIP image data is output to the display control unit 12.

  Specifically, as shown in FIG. 3, the MIP image data creation unit 11 creates MIP image data by performing MIP processing for the inside of the 3DROI 18.

  Further, the MIP image data creation unit 11 creates MinIP image data by performing MinIP processing for the range occupied by the 3DROI 18 instead of performing MIP processing, or creates MPR image data by performing MPR processing. It is also possible to create MPR image data with thickness.

  If there is no information related to 3DROI in the ROI information storage unit 6, the MIP image data creation unit 11 does not perform MIP processing or MPR processing.

  The display control unit 12 superimposes the 2DROI image data, the VR image data, and the MIP image data on the screen 13a of the display unit 13. At this time, if an MIP image has been created, the display control unit 12 causes the display unit 13 to display the VR image and the MIP image in a superimposed manner. On the other hand, when the MIP image is not created, only the VR image is displayed on the display unit 13. When the MIP image data creation unit 11 creates MinIP image data, MPR image data, or MPR image data with thickness instead of the MIP image data, the display control unit 12 displays the images and VRs. The image is superimposed on the image and displayed on the display unit 13.

  The display unit 13 is configured by a liquid crystal display, a CRT, or the like, and displays a VR image, a superimposed image of the VR image and the MIP image, and the like.

  The image processing apparatus 1 reads the image processing program, thereby functioning the input analysis unit 3, function of the ROI information calculation unit 4, function of the 2DROI image data creation unit 9 belonging to the image processing unit, and function of the VR image data creation unit 10. The function and the function of the MIP image data creation unit 11 are executed.

(Function)
Next, the operation (image processing method) of the image processing apparatus according to the first embodiment of the present invention will be described with reference to FIG. FIG. 4 is a flowchart showing the operations of the image processing apparatus according to the first embodiment of the present invention in order.

  As a premise for performing processing by the image processing apparatus 1, volume data of a subject is collected in advance by a medical image diagnostic apparatus such as an X-ray CT apparatus, and the volume data is stored in the volume data storage unit 5. Here, as an example, a case will be described in which a scan is performed in a state where a contrast medium is injected into a blood vessel of a subject, and a blood vessel into which the contrast medium is injected is observed.

(Step S01)
First, in step S01, the operator uses the input unit 2 to set an opacity (opacity) so that the CT value range (approximately 200 or more) of the blood vessel and bone into which the contrast medium has been injected becomes opaque.

(Step S02)
In step S02, the VR image data creation unit 10 reads the volume data from the volume data storage unit 5, and creates VR image data by performing volume rendering on the volume data. At this time, the VR image data creation unit 10 performs volume rendering with the opacity (opacity) set in step S01 to create VR image data. In step S01, the operator uses the input unit 2 to set an opacity (opacity), and the VR image data creation unit 10 performs volume rendering using the opacity (opacity). Volume rendering may be performed using the opacity (opacity) stored in the processing device 1.

  The VR image data is output to the display control unit 12, and the display control unit 12 causes the display unit 13 to display a VR image based on the VR image data. Since the opacity (opacity) is set so that the blood vessels and bones are opaque, a VR image representing the blood vessels and bones is displayed on the display unit 13, and the operator can observe the blood vessels and bones.

(Step S03)
In step S03, the operator designates a lesioned part while observing the VR image displayed on the display unit 13. Here, a case where a lesion is present in a blood vessel into which a contrast agent has been injected will be described. The operator uses the input unit 2 (mouse) to click a lesion on the screen of the display unit 13. For example, when a bone and a blood vessel overlap each other and are displayed on the display unit 13 and a bone is present in front of the blood vessel, the VR image is rotated and displayed on the display unit 13 so that the blood vessel can be observed. Then, in a state where the blood vessel is displayed, the operator designates a lesion on the blood vessel using the mouse (input unit 2).

(Step S04)
In step S04, the input analysis unit 3 obtains the coordinates of the clicked position in the coordinate system (orthogonal coordinate system) of the two-dimensional screen, and uses these coordinates as the coordinates of the center of the 2DROI. For example, as shown in FIG. 2, when the center point 14 of the 2DROI is clicked with the mouse (input unit 2) on the screen 13a of the display unit 13, the input analysis unit 3 performs two-dimensional analysis on the center point 14. The coordinates in the screen coordinate system (orthogonal coordinate system) are obtained. The coordinates of the center point 14 of the 2DROI are output to the ROI information calculation unit 4 and the ROI information storage unit 6 and stored in the ROI information storage unit 6.

  When the center point 14 is designated by the operator, the display control unit 12 displays a circular default 2DROI 15 centered on the center point 14 on the screen 13 a of the display unit 13. The shape and size of the 2DROI 15 can be changed by the operator. In this case, when the operator drags the mouse (input unit 2), the input analysis unit 3 sets the shape and size of the dragged range as the shape and size of the 2DROI. Information indicating the shape and size of the 2DROI 15 is output to the ROI information calculation unit 4 and the ROI information storage unit 6 and stored in the ROI information storage unit 6. When the 2DROI 15 is moved, the input analysis unit 3 calculates the coordinates of the new center point 14 of the 2DROI 15 in the screen coordinate system (orthogonal coordinate system). The coordinates of the new center point 14 are output to the ROI information calculation unit 4 and the ROI information storage unit 6 and stored in the ROI information storage unit 6.

(Step S05)
In step S05, the ROI information calculation unit 4 obtains the coordinates of the center of the three-dimensional region of interest (3DROI). The ROI information calculation unit 4 receives the coordinates of the center point 14 of the 2DROI 15 from the input analysis unit 3 and obtains the coordinates of the center of the 3DROI. Specifically, as shown in FIG. 3, the ROI information calculation unit 4 projects the center point 14 of the 2DROI 15 in the projection direction (the depth direction of the screen), and an opaque tissue (blood vessel 16) existing in the projection direction. ) Is determined as the 3DROI center point, and the coordinates of the center point P in the volume coordinate system (orthogonal coordinate system) are obtained. Here, a range in which the opacity (opacity) is set to a predetermined value (for example, 0.8 or more) is set as an opaque tissue, and the blood vessel 16 is included in the range. The coordinates of the center of the 3DROI are output to and stored in the ROI information storage unit 6.

(Step S06)
In step S06, the ROI information calculation unit 4 determines the 3DROI range by determining the shape and size of the 3DROI. As shown in FIG. 3, since the shape of the 2DROI 15 drawn on the screen 13a of the display unit 13 is circular, the ROI information calculation unit 4 projects the circular 2DROI 15 in the projection direction (the depth direction of the screen). A cylindrical shape is formed by projection. Then, by determining the thickness L2 in the projection direction, the shape and size of the 3DROI 18 are determined.

  The thickness L2 in the projection direction of the 3DROI 18 may be arbitrarily specified by the operator, or the ROI information calculation unit 4 may automatically determine it. In the case of automatic determination, when the thickness in the projection direction of the opaque tissue (blood vessel 16) is set to the thickness L1, as shown in FIG. 3, the ROI information calculation unit 4 calculates the thickness L2 of the 3DROI 18 using the formula “ Thickness L2 = thickness L1 × coefficient k ”.

  When the range (shape and size) of the 3DROI 18 is determined as described above, information (shape and size) indicating the range of the 3DROI 18 is output to and stored in the ROI information storage unit 6.

(Step S07)
In step S07, the 2DROI image data creation unit 9 reads information indicating the shape and size of the 2DROI from the ROI information storage unit 6, and creates 2DROI image data based on the information.

  In step S07, the VR image data creation unit 10 reads the volume data from the volume data storage unit 5, and creates the VR image data by performing volume rendering on the volume data. At this time, information (shape and size) indicating the coordinates of the center point P of the 3DROI 18 and the range of the 3DROI 18 stored in the ROI information storage unit 6 is read. Then, the VR image data creation unit 10 removes the area occupied by the 3DROI 18 from the volume data, and performs volume rendering for the area excluding the areas before and after the 3DROI 18 from the viewpoint of the projection direction (the depth direction of the screen). Do. Thus, VR image data that does not include the area occupied by the 3DROI 18 and the areas before and after the 3DROI 18 in the projection direction (the depth direction of the screen) is created.

Further, in step S07, the MIP image data creation unit 11 reads the volume data from the volume data storage unit 5 and the center point P of the 3DROI 18 from the ROI information storage unit 6.
Are read and information (shape and size) indicating the range of 3DROI 18 is read, and MIP processing is performed on the inside of 3DROI 18 to create MIP image data. Specifically, as shown in FIG. 3, the MIP image data creation unit 11 creates MIP image data by performing MIP processing for the inside of the 3DROI 18. Note that MinIP processing, MPR processing, or MPR processing with thickness may be performed instead of MIP processing.

(Step S08)
In step S08, the display control unit 12 causes the display unit 13 to superimpose a 2DROI image based on the 2DROI image data, a VR image based on the VR image data, and an MIP image based on the MIP image data. As a result, the MIP image is superimposed on the VR image and displayed on the screen of the display unit 13, and a 2DROI marker is further displayed.

  The superimposed image will be described with reference to FIG. FIG. 5 is a diagram showing an image superimposed and displayed by the image processing apparatus according to the first embodiment of the present invention. On the screen 13a of the display unit 13, a VR image 21, a MIP image 22, and a 2DROI image 23 are superimposed and displayed. The VR image 21 shows bones and blood vessels injected with a contrast agent, and the MIP image 22 shows blood vessels present in the 3DROI 18 among blood vessels injected with a contrast agent. Bone is present on the front side of the blood vessel existing in 3DROI 18, but volume rendering is not performed on the range overlapping with 3DROI 18, so the bone existing on the front side of the blood vessel existing in 3DROI 18 is drawn. Never happen.

  As described above, the MIP process is performed on the area included in the 3DROI 18 to display the MIP image 22 suitable for detailed diagnosis, and the volume rendering is not performed on the areas existing before and after the 3DROI 18. It is possible to observe a detailed image of a lesion existing in Further, since the surrounding tissue of the lesioned part is displayed as the VR image 21, it is possible to easily grasp the positional relationship between the lesioned part and the surrounding tissue. This makes it possible to easily grasp the positional relationship between the lesion and the surrounding tissue while performing a detailed diagnosis of the lesion.

  Note that when the operator moves the 2DROI on the screen of the display unit 13 or rotates the VR image, the process of step S09 and the process of step S10 described below are executed.

(Step S09)
In step S09, the operator drags the 2DROI image 23 displayed on the display unit 13 with the mouse (input unit 2) to move the 2DROI image 23. The input analysis unit 3 obtains a new center coordinate of the 2DROI along with the movement (step S04). As described above, the processing from step S05 to step S08 is executed, and MIP images of different regions of interest are displayed on the display unit 13.

(Step S10)
In step S10, the operator rotates the VR image 21 by dragging the VR image 21 displayed on the display unit 13 with the mouse (input unit 2). The input analysis unit 3 obtains a rotation matrix around the center point P of the 3DROI 18 so that the VR image is rotated by the rotation amount designated by the operator, and stores the rotation matrix in the display condition storage unit 8.

  The VR image data creation unit 10 performs volume rendering on the volume data in accordance with this rotation matrix, thereby creating VR image data rotated by a designated rotation amount (step S07). Then, as described above, 2DROI image data and MIP image data are created in step S07, synthesized in step S08, and displayed on the display unit 12.

  Since the position, shape, and size of the 2DROI on the screen 13a of the display unit 13 are not changed, a new 3DROI is created, and MIP processing is performed on the range to create MIP image data. For other areas, volume rendering is performed to create VR image data.

  The processes in steps S09 and S10 are executed only when an operation is performed by the operator. Therefore, in this embodiment, it is possible to achieve the effects of the present invention without executing the processes in steps S09 and S10.

  The volume rendering executed by the VR image data creation unit 10 may be volume rendering by a parallel projection method or volume rendering by an isometric projection method. Furthermore, MIP image data and MPR image data with thickness may be created in an area other than the 3DROI 18.

(Modification)
Next, a modification of the image processing apparatus according to the first embodiment will be described. When the operator designates a point on the screen 13a of the display unit 13 using the input unit 2, the shape and size of the default 2DROI are determined according to the diagnostic part existing at the designated point position. You may do it. For example, information (head, chest, abdomen, whole body, etc.) indicating which range of the subject has been scanned is added to the volume data collected by the medical image diagnostic apparatus as supplementary information in advance. Then, clustering data in which each area (each cluster) of the volume data is associated with the diagnosis part is created and stored in advance. For example, when the abdomen is scanned in a range including the heart, the kidney, and the like, each region (cluster) of the obtained volume data is associated with the diagnosis site (the heart, the kidney, etc.). Furthermore, each diagnostic part is associated with the shape and size of the 2DROI.

  The ROI information calculation unit 4 determines to which region (cluster) of the volume data the point on the screen 13a designated by the operator belongs, and based on the clustering data, the diagnosis corresponding to that region (cluster) Determine the site (eg, heart, kidney, etc.). Then, the ROI information calculation unit 4 sets the 2DROI associated with the diagnosis site (heart, kidney, etc.) as the default 2DROI shape and size. For example, when an aorta is designated in the abdomen, an oval 2DROI having a width of about 5 cm and a length of about 10 cm registered for the aorta is set as a default 2DROI. The default 2DROI shape and size may be newly registered by the operator.

  Also, 3DROI information (shape and size) may be set in advance according to the symptom, and the 3DROI may be used as the default 3DROI.

  Information for specifying the default 2DROI or 3DROI according to the diagnosis site or symptom may be displayed on the display unit 13 so that the operator can select them.

[Second Embodiment]
Next, the configuration of an image processing apparatus according to the second embodiment of the present invention will be described with reference to FIG. FIG. 7 is a block diagram showing a configuration of an image processing apparatus according to the second embodiment of the present invention.

  The image processing apparatus 30 according to the second embodiment is different from the image processing apparatus 1 according to the first embodiment in that an object data creation unit 31 is provided instead of the ROI information calculation unit 4. The object data created by the object data creation unit 31 is stored in the object data storage unit 32. Further, the input analysis unit 3 creates a condition for creating object data in addition to the processing in the first embodiment. The configuration other than the object data creation unit 31 and the object data storage unit 32 is the same as the configuration of the image processing equipment 1 according to the first embodiment, and the same processing can be executed.

  The image processing apparatus 30 according to the second embodiment differs from the image processing apparatus 1 according to the first embodiment in the 3DROI range determination method, and superimposes a MIP image, an MPR image, or the like on the VR image. Is displayed in the same manner as the image processing apparatus 1 according to the first embodiment.

  When the threshold value of the CT value is input by the input unit 2, the input analysis unit 3 sets “1” to a voxel having a CT value equal to or greater than the threshold and “0” to a voxel having a CT value less than the threshold. Create object data creation conditions. The object data creation condition is output to the object data creation unit 31.

  Also, when the expansion width for 3DROI is input at the input unit 2, the input analysis unit 3 sets the input width as the expansion width of 3DROI, and outputs the expansion width to the ROI information storage unit 6 for storage. .

  The object data creation unit 31 creates object data based on the object data creation conditions sent from the input analysis unit 3 and the volume data stored in the volume data storage unit 5. For example, for the volume data, the object data creation unit 31 creates object data by setting a voxel having a CT value greater than or equal to a set threshold value to “1” and a voxel having a CT value less than the threshold value as “0”. The object data is output to and stored in the object data storage unit 32.

  In the case of a blood vessel into which a contrast agent has been injected, object data representing a blood vessel region into which a contrast agent has been injected can be created by setting a CT value of approximately 200 or more as a threshold range. However, since the CT value range of the bone region overlaps the CT value range of the blood vessel region, only the blood vessel region is extracted by deleting the bone region from the object data so that the bone region is not the target region of the MIP process. Create the object data. A method for extracting object data of a blood vessel region is performed by a known method.

  The 2DROI image data creation unit 9 reads the object data stored in the object data storage unit 32 and the expansion width stored in the ROI information storage unit 6 and expands the object data by the expansion width. Are projected in the projection direction (direction toward the screen), and the obtained contour is set as 2DROI image data. For example, as shown in the schematic diagram of FIG. 8, a range obtained by expanding the range occupied by the object data (the range corresponding to the blood vessel 16) by the expansion width is defined as 3DROI 33, and the range is the projection direction (the direction toward the screen 13a). An outline 34 obtained by projecting onto the 2D image is taken as a 2DROI image.

  The VR image data creation unit 10 reads the volume data from the volume data storage unit 5 and does not perform volume rendering for the region where the 3DROI 33 is projected in the projection direction (the depth direction of the screen) as shown in the schematic diagram of FIG. , Volume rendering is applied to other areas. As a result, VR image data that does not include the area occupied by the 3DROI 33 and the areas before and after the 3DROI 33 in the projection direction (the depth direction of the screen) is created.

  The MIP image data creation unit 11 reads volume data from the volume data storage unit 5, reads object data from the object data storage unit 32, and further reads an expansion width from the ROI information storage unit 6, and reads the object data for the expansion width. The MIP image data is created by performing the MIP process on the 3DROI 33 as a target with the expanded range as 3DROI33.

(Function)
Next, the operation (image processing method) of the image processing apparatus according to the second embodiment of the present invention will be described with reference to FIG. FIG. 9 is a flowchart showing the operations of the image processing apparatus according to the second embodiment of the present invention in order.

  Similarly to the first embodiment, the volume data of the subject is collected in advance by the medical image diagnostic apparatus and the volume data is stored in the volume data storage unit 5.

(Step S20)
First, in step S20, the operator sets the opacity (opacity) so that the CT value range (approximately 200 or more) of the blood vessel and bone into which the contrast medium has been injected becomes opaque.

(Step S21)
In step S21, the VR image data creation unit 10 reads volume data from the volume data storage unit 5, and creates VR image data by performing volume rendering on the volume data. At this time, the VR image data creation unit 10 performs volume rendering with the opacity (opacity) set in step S20, and creates VR image data. The VR image data is output to the display control unit 12, and the display control unit 12 causes the display unit 13 to display an image based on the VR image data.

(Step S22)
In step S22, the threshold value of the CT value is input by the input unit 2, and the voxel having a CT value equal to or greater than the input threshold value is input by the input analysis unit 3 is “1”, and the voxel having a CT value less than the threshold value is “0”. Is created as an object data creation condition. The object data creation conditions are output to the object data creation unit 31.

(Step S23)
In step S23, the object data creation unit 31 reads the volume data from the volume data storage unit 5, and creates object data according to the object data creation conditions output from the input analysis unit 3. Specifically, for the read volume data, the object data creation unit 31 sets voxels having a CT value equal to or greater than a set threshold value to “1”, and sets voxels having a CT value less than the threshold value to “0”. Create object data. Then, the object data creation unit 31 outputs the object data to the object data storage unit 32 and stores it.

(Step S24)
In step S <b> 24, the operator inputs the expansion width for the 3DROI using the input unit 2. The input analysis unit 3 sets the input width as a 3DROI expansion width, and outputs the expansion width to the ROI information storage unit 6 for storage. Note that an initial value of the expansion width of the 3DROI may be set in advance and stored in the ROI information storage unit 6. When the expansion width is set in advance, the operator does not need to input the expansion width, and therefore the process in step S24 is executed only when the expansion width is input by the operator.

(Step S25)
In step S25, the MIP image data creation unit 11 reads the object data from the object data storage unit 22, reads the expansion width from the ROI information storage unit 6, and expands the range in which the object data is expanded by the expansion width as 3DROI. To do. For example, as shown in the schematic diagram of FIG. 8, a range in which the range occupied by the object data (the range corresponding to the blood vessel 16) is expanded by the expansion width is defined as 3DROI 33.

(Step S26)
In step S26, the MIP image data creation unit 11 reads the volume data from the volume data storage unit 5, and creates MIP image data by performing MIP processing on the volume data for the range of the 3DROI 33.

  In step S26, the VR image data creation unit 10 reads the volume data from the volume data storage unit 5 and creates VR image data by performing volume rendering on the volume data. At this time, as shown in the schematic diagram of FIG. 8, volume rendering is not performed on the region where the 3DROI 33 is projected in the projection direction (the depth direction of the screen), and volume rendering is performed on the other regions. As a result, VR image data that does not include the area occupied by the 3DROI 33 and the areas before and after the 3DROI 33 in the projection direction (the depth direction of the screen) is created.

  The 2DROI image data creation unit 9 reads the object data stored in the object data storage unit 32, reads the expansion width from the ROI information storage unit 6, and expands the object data by the expansion width. A contour obtained by projecting (the range occupied by the 3DROI 33) in the projection direction (direction toward the screen) is defined as a 2DROI image. For example, as shown in FIG. 8, a contour 34 obtained by projecting the 3DROI 33 in the projection direction (the direction toward the screen 13a) is set as a 2DROI image.

(Step S27)
In step S27, the display control unit 12 superimposes the 2DROI image based on the 2DROI image data, the VR image based on the VR image data, and the MIP image based on the MIP image data, and displays them on the display unit 13. As a result, the MIP image is superimposed on the VR image and displayed on the screen of the display unit 13, and a 2DROI marker is further displayed.

  The superimposed image will be described with reference to FIG. FIG. 10 is a diagram showing an image superimposed and displayed by the image processing apparatus according to the second embodiment of the present invention. On the screen 13a of the display unit 13, a VR image 35, a MIP image 36, and a 2DROI image 37 are superimposed and displayed. The VR image 35 shows bones and blood vessels injected with a contrast agent, and the MIP image 36 shows blood vessels present in the 3DROI 33 among blood vessels injected with contrast agents. Bone is present on the front side of the blood vessel existing in 3DROI 33, but volume rendering is not performed on the range overlapping with 3DROI 33, so bones existing on the front side of blood vessel existing in 3DROI 33 are not drawn. .

  As described above, the MIP process is performed on the area included in the 3DROI 33, the MIP image 36 suitable for detailed diagnosis is displayed, and the volume rendering is not performed on the areas existing before and after the 3DROI 33. It is possible to observe a detailed image of a lesion existing in Moreover, since the surrounding tissue of the lesioned part is displayed as the VR image 35, the positional relationship between the lesioned part and the surrounding tissue can be easily grasped. This makes it possible to easily grasp the positional relationship between the lesion and the surrounding tissue while performing a detailed diagnosis of the lesion.

  In the case of rotating the VR image, the process of step S28 described below is executed.

(Step S28)
In step S28, the operator rotates the VR image by dragging the VR image displayed on the display unit 13 with the mouse (input unit 2). The input analysis unit 3 obtains a rotation matrix so that the VR image is rotated by a rotation amount designated by the operator around a predetermined rotation center point, and stores the rotation matrix in the display condition storage unit 8.

  The VR image data creation unit 10 creates the VR image data rotated by the designated rotation amount by performing volume rendering on the volume data in accordance with the rotation matrix (step S26). Then, as described above, 2DROI image data, MIP image data, and VR image data are created in step S26, combined in step S27, and displayed on the display unit 12.

1 is a block diagram illustrating a configuration of an image processing apparatus according to a first embodiment of the present invention. It is a schematic diagram for demonstrating the positional relationship of the screen of a blood vessel, a surrounding tissue (bone), and a display part. It is a schematic diagram for demonstrating the process which calculates | requires the range of a three-dimensional region of interest (3DROI). 3 is a flowchart illustrating operations of the image processing apparatus according to the first embodiment of the present invention in order. It is a figure which shows the image superimposed and displayed by the image processing apparatus which concerns on 1st Embodiment of this invention. It is a schematic diagram for demonstrating the process which calculates | requires the range of a three-dimensional region of interest (3DROI) in the modification of the image processing apparatus which concerns on 1st Embodiment of this invention. It is a block diagram which shows the structure of the image processing apparatus which concerns on 2nd Embodiment of this invention. It is a schematic diagram for demonstrating object data. It is a flowchart which shows the operation | movement of the image processing apparatus which concerns on 2nd Embodiment of this invention in order. It is a figure which shows the image superimposed and displayed by the image processing apparatus which concerns on 2nd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image processing apparatus 2 Input part 3 Input analysis part 4 ROI information calculation part 5 Volume data storage part 6 ROI information storage part 7 VR condition storage part 8 Display condition storage part 9 2DROI image data creation part 10 VR image data creation part 11 MIP Image data creation unit 12 Display control unit 13 Display unit 31 Object data creation unit 32 Object data storage unit

Claims (14)

A first image for generating first three-dimensional image data by projecting a desired three-dimensional region of interest onto a projection plane viewed from a viewpoint in a predetermined direction with respect to the volume data collected by the medical image diagnostic apparatus. Creating means;
A region other than the desired three-dimensional region of interest and the region before and after the desired three-dimensional region of interest when viewed from the viewpoint in the predetermined direction in the volume data is projected onto the projection plane, thereby generating a second A second image creation means for creating three-dimensional image data;
Display control means for superimposing an image based on the first three-dimensional image data and an image based on the second three-dimensional image data on a display means;
An image processing apparatus comprising:   The first image creating means creates the first three-dimensional image data by performing MIP processing, MinIP processing, or MPR processing on the desired three-dimensional region of interest. Item 8. The image processing apparatus according to Item 1.   The first image creating means creates MPR image data by performing MPR processing on the desired three-dimensional region of interest, adds a plurality of MPR image data in the predetermined direction, and averages the thickness. The image processing apparatus according to claim 1, wherein attached MPR image data is created.   4. The image processing apparatus according to claim 1, wherein the second image creating unit creates the second three-dimensional image data by performing volume rendering. 5. The display control means causes the display means to display an image based on the three-dimensional image data obtained by performing volume rendering on the entire range of the volume data, and further from the input means to the display means. Accepting designation of an arbitrary point on the screen, and displaying a two-dimensional ROI marker centered on the designated point on the screen of the display means,
The first image creating means includes
Projecting a range occupied by the two-dimensional ROI marker in the predetermined direction, obtaining a range of a three-dimensional region of interest on the basis of an opaque tissue intersecting with the volume data, and projecting the three-dimensional region of interest onto the projection plane 5. The image processing apparatus according to claim 1, wherein the first three-dimensional image data is created.   The first image creation means obtains a center position in the predetermined direction of the opaque tissue, sets a range of a predetermined thickness around the center position as a range of the three-dimensional region of interest, and sets the three-dimensional region of interest. The image processing apparatus according to claim 5, wherein the first three-dimensional image data is created by projecting the image onto the projection plane.   The image processing apparatus according to claim 5, wherein the opaque tissue is an area in which an opacity (opacity) is set to a predetermined value or more.   When the two-dimensional ROI marker is moved on the screen of the display means, the first image creating means changes the position of the three-dimensional region of interest in accordance with the movement, and the first three-dimensional image data The image processing apparatus according to any one of claims 5 to 7, wherein the image processing apparatus is configured.   When the second three-dimensional image data is rotated on the screen of the display means, the first image creation means changes the direction in the predetermined direction according to the rotation and changes the desired three-dimensional region of interest. The image processing apparatus according to claim 1, wherein the first three-dimensional image data is created by projecting the image onto a projection plane.   The first image creating means creates a first three-dimensional image data targeting the three-dimensional region of interest using a region based on preset object data as a three-dimensional region of interest. The image processing apparatus according to claim 1.   The first image creation means creates a first three-dimensional image data for the three-dimensional region of interest, with a region expanded by a predetermined range of the region occupied by the object data as a three-dimensional region of interest. The image processing apparatus according to claim 10.   5. The first image creation unit creates first 3D image data for a 3D region of interest set in advance according to a diagnosis site or symptom. An image processing apparatus according to any one of the above. On the computer,
A first image for generating first three-dimensional image data by projecting a desired three-dimensional region of interest onto a projection plane viewed from a viewpoint in a predetermined direction with respect to the volume data collected by the medical image diagnostic apparatus. Create function,
By excluding the desired three-dimensional region of interest from the volume data and projecting a region excluding the region before and after the desired three-dimensional region of interest from the viewpoint in the predetermined direction, A second image creation function for creating two three-dimensional image data;
A display control function for superimposing an image based on the first three-dimensional image data and an image based on the second three-dimensional image data on a display means;
An image processing program for executing A first image for generating first three-dimensional image data by projecting a desired three-dimensional region of interest onto a projection plane viewed from a viewpoint in a predetermined direction with respect to the volume data collected by the medical image diagnostic apparatus. Creation steps,
By excluding the desired three-dimensional region of interest from the volume data and projecting a region excluding the region before and after the desired three-dimensional region of interest from the viewpoint in the predetermined direction, A second image creation step for creating two three-dimensional image data;
A display step of superimposing an image based on the first three-dimensional image data and an image based on the second three-dimensional image data on a display means;
An image processing method comprising:

Images