JP2014000182A - Medical image generating device and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a medical image generating device and program capable of creating an integrated cross-sectional image from which a tissue region to be diagnosed or used for other purposes can be drawn without being affected by the size or shape of the tissue region.SOLUTION: A first color specification value function f1 that specifies the correspondence between CT values and density values and a first opacity function g1 that specifies the correspondence between CT values and opacities are applied to CT image data to create first cross-sectional image data. A second color specification value function f2 that specifies the correspondence between MRI signal strength values and color specification values and a second opacity function g2 that specifies the correspondence between MRI signal strength values and opacities are applied to MRI image data to create second cross-sectional image data. The first cross-sectional image data and the second cross-sectional image data are integrated in a common coordinate system to create integrated cross-sectional image data. From the integrated cross-sectional image data, an integrated cross-sectional image is created and displayed.

Description

  The present invention relates to a technique for supporting image diagnosis, and in particular, medical image data (hereinafter appropriately referred to as “CT image data”) obtained by an X-ray CT (Computed Tomography) image diagnosis apparatus, MRI ( A plurality of medical cross-sectional images generated based on different medical image data such as medical image data (hereinafter referred to as “MRI image data” as appropriate) obtained by an image diagnostic apparatus (Magnetic Resonance Imaging) are superimposed on each other. The present invention relates to a medical image generation apparatus and a program suitable for generating an integrated integrated cross-sectional image.

  Medical image data (volume data) obtained by an image diagnostic apparatus such as X-ray CT or MRI is reconstructed two-dimensionally using a computer such as a computer, so that a medical cross-sectional image corresponding to an arbitrary cross-section can be obtained. It can be created. Such medical cross-sectional images can be used to confirm the size and shape of a site of interest such as an organ or tumor to be diagnosed, to create a surgical plan for extracting the site of interest, or to be used for explanation to patients, etc. Used for various purposes.

  Depending on the type of the diagnostic imaging apparatus, the biological tissue that can be drawn well may differ. For example, a cross-sectional image of the head generated from CT image data of the X-ray CT image diagnostic apparatus (hereinafter referred to as “CT cross-sectional image” as appropriate) and a head of the head generated from MRI image data of the MRI image diagnostic apparatus. Comparing with cross-sectional images (hereinafter referred to as “MRI cross-sectional images” as appropriate), in CT cross-sectional images, bones such as skulls can be drawn well, but brain parenchyma cannot be drawn well. On the other hand, the MRI cross-sectional image has a characteristic that the brain parenchyma can be satisfactorily depicted but the bone part cannot be satisfactorily depicted.

  For this reason, when both the skull and the brain parenchyma are to be diagnosed, a CT cross-sectional image and an MRI cross-sectional image related to the same head are displayed side by side and interpreted while comparing them. However, interpretation (image diagnosis) while comparing a plurality of images puts a heavy burden on the doctor who performs the interpretation, and thus it is possible to obtain one cross-sectional image in which each tissue to be diagnosed is well depicted. It is requested.

  As a technique that meets such a demand, an image generation technique disclosed in Patent Document 1 has been proposed. In this image generation technique, a region where a living tissue that is well depicted in a CT cross-sectional image is located (hereinafter referred to as “tissue region” where appropriate) and a tissue region that is well depicted in an MRI cross-sectional image are mutually connected. The images are combined and displayed as one cross-sectional image (integrated cross-sectional image).

JP-A-8-31801

  The image generation technique disclosed in Patent Document 1 requires a work of extracting a well-depicted tissue region to be diagnosed from a CT cross-sectional image or an MRI cross-sectional image. This is done by designating the shape and position of the tissue region while the operator sees the cross-sectional image. For this reason, when the extracted tissue region is small and the shape is simple, it is possible to generate a good integrated sectional image because the extraction is easy, but the tissue region is large or the shape is complicated. In such a case, there is a problem that it is difficult to generate a good integrated cross-sectional image because it is difficult to extract a tissue region.

  The present invention has been made in view of such circumstances, and can generate an integrated cross-sectional image that can satisfactorily depict a tissue region to be diagnosed or the like without being affected by the size or shape of the tissue region. An object of the present invention is to provide a possible medical image generation apparatus and program.

  In order to achieve the above object, a medical image generation apparatus and program according to the present invention have the following features.

That is, the medical image generation apparatus according to the present invention is
An integrated cross-sectional image is generated by integrating the first cross-sectional image generated based on the first medical image data and the second cross-sectional image generated based on the second medical image data so as to overlap each other. A medical image generating device for
A first color value function that creates a first color value function that defines the correspondence between the original data value of the first medical image data and the color value when the first cross-sectional image is displayed. Creating means;
A second color value function that creates a second color value function that defines the correspondence between the original data value of the second medical image data and the color value when the second cross-sectional image is displayed. Creating means;
First opacity function creating means for creating a first opacity function that defines the correspondence between the original data value of the first medical image data and the opacity of the first cross-sectional image;
Second opacity function creating means for creating a second opacity function that defines the correspondence between the original data value of the second medical image data and the opacity of the second cross-sectional image;
First cross-sectional image data carrying each information of the color value and the opacity associated with the first color value function and the first opacity function from the first medical image data, respectively. First sectional image data creating means for creating
Second cross-sectional image data carrying each information of the color value and the opacity associated with the second color value function and the second opacity function from the second medical image data, respectively. Second cross-sectional image data creating means for creating
Integrated cross-sectional image data creating means for creating integrated cross-sectional image data by integrating the first cross-sectional image data and the second cross-sectional image data;
And an integrated cross-sectional image generating means for generating the integrated cross-sectional image displayed on the display screen based on the integrated cross-sectional image data.

  In the medical image generation apparatus according to the present invention, the first medical image data may be X-ray CT image data, and the second medical image data may be MRI image data.

  Further, in a predetermined common coordinate system, alignment means for aligning the first medical image data and the second medical image data can be provided.

  An instruction input means for inputting an instruction for determining each of the first color value function, the second color value function, the first opacity function, and the second opacity function. The first color value function creating means, the second color value function creating means, the first opacity function creating means, and the second opacity function creating means are the instruction input means. Each of the functions can be created based on the instruction input via the interface.

  Moreover, you may provide the integrated cross-section image data storage means which memorize | stores the said integrated cross-section image data in a predetermined image file format.

  In addition, first cross-sectional image generation display means for generating the first cross-sectional image displayed on the display screen based on the first cross-sectional image data, and the display screen based on the second cross-sectional image data And a second cross-sectional image generation / display unit configured to generate the second cross-sectional image displayed above.

  Moreover, it produces | generates based on the said 1st cross-sectional image produced | generated based on the said 1st cross-sectional image data, the said 2nd cross-sectional image produced | generated based on the said 2nd cross-sectional image data, and the said integrated cross-sectional image data It is preferable that the integrated cross-sectional image is configured to be displayed on the display screen at the same time.

In addition, the medical image generation program according to the present invention includes:
An integrated cross-sectional image is generated by integrating the first cross-sectional image generated based on the first medical image data and the second cross-sectional image generated based on the second medical image data so as to overlap each other. A medical image generation program for performing
A first color value function that creates a first color value function that defines the correspondence between the original data value of the first medical image data and the color value when the first cross-sectional image is displayed. Creation steps,
A second color value function that creates a second color value function that defines the correspondence between the original data value of the second medical image data and the color value when the second cross-sectional image is displayed. Creation steps,
A first opacity function creating step for creating a first opacity function that defines the correspondence between the original data value of the first medical image data and the opacity of the first cross-sectional image;
A second opacity function creating step for creating a second opacity function that defines the correspondence between the original data value of the second medical image data and the opacity of the second cross-sectional image;
First cross-sectional image data carrying each information of the color value and the opacity associated with the first color value function and the first opacity function from the first medical image data, respectively. A first cross-sectional image data creation step for creating
Second cross-sectional image data carrying each information of the color value and the opacity associated with the second color value function and the second opacity function from the second medical image data, respectively. A second sectional image data creation step for creating
An integrated cross-sectional image data creating step for creating integrated cross-sectional image data by integrating the first cross-sectional image data and the second cross-sectional image data;
An integrated cross-sectional image generation and display step of generating the integrated cross-sectional image displayed on a display screen based on the integrated cross-sectional image data is executed by a computer.

  The “original data value” means a specific measurement value carried by medical image data (for example, a CT value in CT image data or a signal intensity value in MRI image data). Further, the “color value” means a value (for example, tristimulus value) that defines a color (including not only a chromatic color but also an achromatic color) when displayed.

  According to the medical image generation apparatus and the program according to the present invention, the first cross-sectional image data and the second cross-sectional image data carrying the colorimetric value information and the opacity information from the first medical image data and the second medical image data. Are generated, and an integrated cross-sectional image is generated based on integrated cross-sectional image data obtained by integrating these cross-sectional image data. The color value and opacity carried by the first cross-sectional image data correspond to the first color value function and the first opacity function based on the original data value of the first medical image data, respectively. The color value and opacity carried by the second cross-sectional image data are based on the original data value of the second medical image data by the second color value function and the second opacity function, respectively. It is associated.

  Since the original data value of the first medical image data (hereinafter referred to as “first original data value” as appropriate) varies depending on the type of living tissue, the first original data value, the color value, A predetermined tissue region suitable for image rendering based on the first medical image data in the cross-sectional image (first cross-sectional image) generated from the first cross-sectional image data by appropriately adjusting the correspondence with the transparency. (Hereinafter, referred to as “first tissue region” as appropriate) can be well drawn.

  The same applies to the original data value of the second medical image data (hereinafter referred to as “second original data value” as appropriate), and the correspondence between the second original data value, the color specification value, and the opacity is appropriately set. By adjusting, in a cross-sectional image (second cross-sectional image) generated from the second cross-sectional image data, a predetermined tissue region suitable for image rendering based on the second medical image data (hereinafter referred to as “second” as appropriate). It is also possible to draw well in the extracted state.

  Therefore, in the integrated cross-sectional image generated based on the integrated cross-sectional image data obtained by integrating the first cross-sectional image data and the second cross-sectional image data, the first tissue region and the second tissue region described above are included. Both can be drawn well. Note that the drawing of the first tissue region by the first cross-sectional image data and the drawing of the second tissue region by the second cross-sectional image data correspond to the extraction of the tissue region in the conventional method. This can be done by associating the color value and the opacity with the original data value of the first medical image data and the original data value of the second medical image data, respectively. The size and shape of the tissue region and the second tissue region are not affected.

  As described above, according to the medical image generation apparatus and program according to the present invention, an integrated cross-sectional image that can satisfactorily depict a tissue region to be diagnosed or the like is generated without being affected by the size or shape of the tissue region. It becomes possible.

1 is a schematic configuration diagram of a medical image generation apparatus according to an embodiment of the present invention. It is a block diagram which shows the internal structure of the arithmetic processing unit shown in FIG. It is a block diagram which shows the functional structure of the arithmetic processing unit shown in FIG. It is a figure which shows the aspect of the display area displayed on the image display part of the image display apparatus shown in FIG. It is a schematic diagram of the 1st cross-sectional image produced | generated based on CT image data. It is a schematic diagram of the 2nd cross-sectional image produced | generated based on MRI image data. It is a schematic diagram of an integrated cross-sectional image. It is a flowchart which shows the flow of a process until integrated cross-section image creation. It is a figure which shows an example of the graph of a 1st color value function. It is a figure which shows an example of the graph of a 1st opacity function. It is a figure which shows an example of the graph of a 2nd color value function. It is a figure which shows an example of the graph of a 2nd opacity function. It is a schematic diagram which shows the outline | summary of the process until integrated cross-section image creation. It is a figure which illustrates the cross-sectional image (a) of the head produced | generated by CT image data, the cross-sectional image (b) of the head produced | generated by MRI image data, and the integrated cross-sectional image (c) by this invention. It is a figure which shows an example of the integrated cross-section image by a conventional method. It is a figure which shows an example of the graph of the color value function in the case of producing | generating a color image. It is a figure which illustrates the color scale (a) of one aspect, and the color scale (b) of another aspect.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the above-mentioned drawings. First, the configuration of a medical image generation apparatus according to an embodiment of the present invention will be described with reference to FIGS.

  A medical image generation apparatus 1 shown in FIG. 1 includes a first cross-sectional image generated based on first medical image data (in this embodiment, CT image data obtained by an X-ray CT image diagnostic apparatus), An integrated cross-sectional image is generated by integrating the second cross-sectional images generated based on the two medical image data (in this embodiment, MRI image data obtained by the MRI image diagnostic apparatus) so as to overlap each other. It has a function, and comprises an arithmetic processing device 10 composed of a computer or the like, an input device 20 composed of a keyboard 21 and a mouse 22, and an image display device 30.

  As shown in FIG. 2, the arithmetic processing unit 10 is a DRAM (Dynamic Random Access) in which a CPU (Central Processing Unit) 101 that executes various arithmetic operations such as image processing, a processing program, image data to be processed, and the like are placed. And a chip set 103 that controls input / output of data to / from the CPU 101, the main memory 102, and the like. The image processing apparatus also includes a GPU (Graphic Processing Unit) 105 that configures a display image based on image data and processing instructions sent from the CPU 101, and a VRAM (Video Random Access Memory) 106 that stores a display image configured by the GPU 105. Between the graphics board 104, a storage device 107 including a hard disk, a data bus 108 that mediates the exchange of data between these components, the input device 20, the image display device 30, and the arithmetic processing device 10 And an interface 109 that mediates exchange of data and the like.

  Further, from a functional viewpoint, the arithmetic processing device 10 has an image data acquisition unit 11, an image data storage unit 12, a function creation unit 13, an image data creation unit 14, and an image generation as shown in FIG. The unit 15 is provided. Each block shown in FIG. 3 includes hardware such as the CPU 101, the main memory 102, the graphics board 104, and the storage device 107 shown in FIG. 2, and various programs executed by the CPU 101 and the GPU 105 (medical image generation according to the present invention). Each function realized by a program (including a program) is made concrete and shown as a component.

  The image data acquisition unit 11 acquires various medical image data obtained by various medical image diagnostic apparatuses. In the present embodiment, the CT image data obtained by the X-ray CT image diagnostic apparatus, MRI image data obtained by the MRI image diagnostic apparatus is configured to be acquired.

  The image data storage unit 12 constitutes integrated cross-sectional image data storage means. The medical image data acquired by the image data acquisition unit 11 and the cross-sectional image data generated by the image data generation unit 14 ( The first cross-sectional image data, the second cross-sectional image data, and the integrated cross-sectional image data (to be described later) are stored.

  The function creation unit 13 creates a function used when the image data creation unit 14 creates cross-sectional image data. The function creation unit 13 includes a first color value function creation unit 131 and a first opacity function creation. Section 132, a second color value function creating section 133, and a second opacity function creating section 134.

  The first color specification value function creating unit 131 corresponds to a first color specification value function creation means, and stores original data values (CT values) carried by CT image data and a first cross-sectional image described later. A first color value function that defines the correspondence with the color value at the time of display is created.

  The first opacity function creation unit 132 corresponds to first opacity function creation means, and defines the correspondence between the CT value of the CT image data and the opacity of the first cross-sectional image described later. A first opacity function is configured to be created.

  The second colorimetric value function creating unit 133 corresponds to a second colorimetric value function creating unit, and includes original data values (signal intensity values) carried by the MRI image data and a second cross-sectional image described later. Is configured to create a second colorimetric value function that defines a correspondence relationship with the colorimetric value when displaying.

  The second opacity function creation unit 134 corresponds to second opacity function creation means, and defines the correspondence between the signal intensity value of the MRI image data and the opacity of the second cross-sectional image described later. Configured to generate a second opacity function.

  In the present embodiment, the first color value function, the first opacity function, the second color value function, and the second opacity function described above are input to the input device 20 ( It is created based on a predetermined instruction (hereinafter referred to as “function creation instruction” as appropriate) input to the arithmetic processing device 10 via the instruction input means in this embodiment (hereinafter referred to as “function creation instruction” as appropriate). A specific function creation instruction mode will be described later).

  The image data creation unit 14 creates various cross-sectional image data described later from the above CT image data and MRI image data. The first cross-sectional image data creation unit 141 and the second cross-sectional image data are created. A unit 142 and an integrated cross-sectional image data creation unit 143.

  The first cross-sectional image data creation unit 141 corresponds to a first cross-sectional image data creation unit, and uses the first color value function and the first opacity function from the CT image data. First cross-sectional image data carrying each information of the color value and opacity associated with each other is created.

  The second cross-sectional image data creation unit 142 corresponds to a second cross-sectional image data creation unit, and uses the second color value function and the second opacity function from the MRI image data. Second cross-sectional image data carrying information on color values and opacity associated with each other is created.

  The integrated cross-sectional image data creation unit 143 corresponds to an integrated cross-sectional image data creation unit and an alignment unit, and includes the first cross-sectional image data generated by the first cross-sectional image data creation unit 141 and the first cross-sectional image data. The second sectional image data generated by the second sectional image data creating unit 142 is integrated to create integrated sectional image data.

  The image generation unit 15 generates each cross-sectional image displayed on the image display unit 31 (see FIG. 1) of the image display device 30 based on each image data generated by the image data generation unit 14. And includes a first slice image generation unit 151, a second image generation unit 152, and an integrated slice image generation unit 153.

  The first cross-sectional image generation unit 151 corresponds to a first cross-sectional image generation unit, and the image display is based on the first cross-sectional image data generated by the first cross-sectional image data generation unit 141. The first cross-sectional image displayed in a predetermined area (display area W1 described later) of the unit 31 is generated.

  The second cross-sectional image generation unit 152 corresponds to a second cross-sectional image generation unit, and the image display is performed based on the second cross-sectional image data generated by the second cross-sectional image data generation unit 142. A second cross-sectional image displayed in a predetermined area (display area W2 described later) of the unit 31 is generated.

  The integrated cross-sectional image generation unit 153 corresponds to an integrated cross-sectional image generation unit. Based on the integrated cross-sectional image data generated by the integrated cross-sectional image data generation unit 143, a predetermined region (described later) of the image display unit 31 is used. The integrated sectional image displayed in the display area W3) is generated.

  In the present embodiment, as shown in FIG. 4, a plurality of display regions (in FIG. 4, four display regions W <b> 1 to W <b> 4 are illustrated) are arranged in the image display unit 31. In the display areas W1 to W4, the following images are displayed. For this reason, an operator such as a doctor can view the images displayed in the display areas W1 to W4 at a time. Note that the number of display areas set and the display contents can be changed as appropriate.

  The display area W1 is an area in which the above-described first cross-sectional image (a first cross-sectional image G1 described later is illustrated in FIG. 4) is displayed, and the display area W2 is the above-described second cross-section image. Is a region in which a cross-sectional image (a second cross-sectional image G2 described below is illustrated in FIG. 4) is displayed. The display area W3 is an area in which the above-described integrated cross-sectional image (an integrated cross-sectional image G3 described later is illustrated in FIG. 4) is displayed. The display area W4 is the above-described first table. An area in which the color value function, the first opacity function, the second color specification value function, and the second opacity function are displayed (in FIG. 4, a first color value function f1 and a first non-display function described later are displayed). The transparency function g1 is illustrated).

  Next, a procedure for creating an integrated cross-sectional image by the medical image generation processing apparatus 1 of the present embodiment will be described mainly with reference to FIGS. This procedure for creating an integrated cross-sectional image is executed based on a medical image generation program according to an embodiment of the present invention.

  In the following description, the schematic cross-sectional images (first cross-sectional image G1, second cross-sectional image G2, and integrated cross-sectional image G3) shown in FIGS. The first cross-sectional image G1 shown in FIG. 5 is a schematic image of a predetermined cross-section (for example, an axial cross-sectional image) constituted by CT image data, and the second cross-sectional image G2 shown in FIG. This is a schematic image of the same cross-section as the first cross-sectional image G1, which is constituted by MRI image data. Further, the integrated cross-sectional image G3 shown in FIG. 7 is a schematic cross-sectional image obtained by integrating the first cross-sectional image G1 and the second cross-sectional image G2. In the present embodiment, these cross-sectional images G1 to G3 are described as achromatic gray images (256 gradations), but may be chromatic color images.

The first cross-sectional image G1, the second cross-sectional image G2, and the integrated cross-sectional image G3 are each divided into three regions R ₁ , R ₂ , and R ₃ . The regions R ₁ and R ₃ can be satisfactorily depicted in the first cross-sectional image G1 based on CT image data, but are well imaged in the second cross-sectional image G2 based on MRI image data. It shows difficult organizational areas. Region R ₂ is the other way, but in the second cross-sectional image G2 based on the MRI image data can be satisfactorily rendered, to better visualize in the first tomographic images G1 based on the CT image data It shows difficult organizational areas.

Hereinafter, a procedure for creating the integrated cross-sectional image G3 will be described.
<1> First color value function creation processing is performed to create a first color value function f1 (see FIG. 9) (first color value function creation step; see step S1 in FIG. 8). This first color value function f1 is created, for example, by the following procedure.

  First, an instruction to create a first color value function f1 by an operator such as a doctor is given via the input device 20 (for example, by a click operation of the mouse 22) in the function creation unit 13 (see FIG. 3). When this instruction is input, the first color value function creation unit 131 of the function creation unit 13 reads out the CT image data stored in the image data storage unit 12, and the CT value carried by the CT image data. Based on the distribution, the first color value function f1 is temporarily created, and a graph of the first color value function f1 created temporarily is displayed in the display area W4 of the image display unit 31.

The first color specification value function f1 defines the correspondence between the CT value carried by the CT image data and the density value of the image when the CT image data is imaged. For example, as shown in FIG. Created in an aspect. In the example shown in FIG. 9, a density value “0” is associated with a CT value less than CT1, and a density value “255” is associated with a CT value greater than CT2. Further, density values ranging from “0 to 255” are linearly associated with CT values in the range from CT1 to CT2 (so that the slope of the graph is constant). The specific numerical values of CT1 and CT2 are set so that the CT value range from CT1 to CT2 matches the CT value range corresponding to the living tissue located in the above-described regions R ₁ and R _3. .

  Next, the operator determines the suitability of the first color specification value function f1 based on the temporarily generated graph of the first color specification value function f1 (in order to facilitate this determination, the provisional creation is performed). A first cross-sectional image to which the first color value function f1 is applied may be generated and displayed in the display area W1). If it is determined that the first table image is inappropriate, the first table image is displayed. An instruction to adjust the color value function f1 is given.

  This adjustment instruction includes, for example, a numerical value indicating the CT value of the window level WL (CT3 in FIG. 9) and a numerical value indicating the window width WW in the graph of the first color value function f1 shown in FIG. It is done by inputting by. When this adjustment instruction is input, the first function creation unit 131 of the function creation unit 13 recreates the first color value function f1 in accordance with the adjustment instruction, and the first color value function f1 The graph is displayed in the display area W4 of the image display unit 31.

  The operator determines whether the recreated first color value function f1 is appropriate. If the operator determines that the first color value function f1 is not appropriate, an instruction to adjust the first color value function f1 is given again. Thus, the adjustment of the first color value function f1 is repeated until the operator determines that the created first color value function f1 is appropriate.

  <2> First opacity function creation processing is performed to create a first opacity function g1 (see FIG. 10) (first opacity function creation step; see step S2 in FIG. 8). The first opacity function g1 is created by the following procedure, for example.

  First, an instruction to the operator to create the first opacity function g1 is sent to the function creation unit 13 (see FIG. 3) of the arithmetic processing device 10 via the input device 20 (for example, by clicking the mouse 22). input. When this instruction is input, the first opacity function creating unit 133 of the function creating unit 13 performs the first color based on the first color value function f1 created by the first color value function creating process. Is temporarily created and a graph of the temporarily created first opacity function g1 is displayed in the display area W4 of the image display unit 31.

  The first opacity function g1 defines the correspondence between the CT value carried by the CT image data and the opacity of the image when the CT image data is imaged. For example, the mode shown in FIG. To be created. In the example shown in FIG. 10, the opacity “for the CT value within the CT value range (CT value range from CT1 to CT2) corresponding to the window width WW in the graph of the first color value function f1 described above. Opacity “0” is associated with the CT values in the other CT value ranges (CT value range less than CT1 and CT value range greater than CT2). The lower limit value of the CT value range associated with “1” may be set to a value smaller than CT1, or the upper limit value of the CT value range associated with opacity “1” may be set to a value greater than CT2. Possible).

  Next, the operator determines whether or not the first opacity function g1 is appropriate based on the temporarily generated graph of the first opacity function g1 (in order to facilitate this determination, the first tentatively generated first opacity function g1 is used). A first cross-sectional image to which the opacity function g1 is applied may be generated and displayed in the display area W1). If determined to be inappropriate, the first opacity function g1 Instructs to adjust.

  The instruction for this adjustment is, for example, the CT value as the lower limit value and the CT value as the upper limit value of the CT value range corresponding to the opacity “1” in the graph of the first opacity function g1 shown in FIG. This is done by inputting in 21. When this adjustment instruction is input, the first opacity function creation unit 132 of the function creation unit 13 recreates the first opacity function g1 in accordance with the adjustment instruction, and the first opacity function g1 The graph is displayed in the display area W4 of the image display unit 31.

  The operator determines whether or not the re-created first opacity function g1 is appropriate. If the operator determines that the first opacity function g1 is not appropriate, an instruction to adjust the first opacity function g1 is given again. Thus, the adjustment of the first opacity function g1 is repeated until the operator determines that the created first opacity function g1 is appropriate.

  <3> First sectional image data creation processing is performed to create first sectional image data (first sectional image data creation step; see step S3 in FIG. 8). As for the first slice image data, the first slice image data creation unit 141 (see FIG. 3) of the image data creation unit 14 reads out the CT image data stored in the image data storage unit 12, and the CT image The data is created by applying the first color value function f1 and the first opacity function g1 described above to the data.

  Here, when the first color value function f1 and the first opacity function g1 are applied to the CT image data, the first color value function f1 and the first opacity are shown in FIG. This means that the CT value carried by each image component in the CT image data is converted into a density value based on the function g1. Note that the first color value function f1 and the first opacity function g1 are applied in such a manner that they are multiplied by the CT image data.

  In other words, the density value “0” associated with the first colorimetric value function f1 and the opacity “0” associated with the first opacity function g1 are associated with an image component having a CT value less than CT1. ”And a density value“ 0 ”(= 0 × 0) multiplied by“, ”and a density value“ 1 ”associated with the first colorimetric value function f1 is assigned to an image component carrying a CT value exceeding CT2. 255 ”is multiplied by the opacity“ 0 ”associated with the first opacity function g1 to give a density value“ 0 ”(= 255 × 0). On the other hand, since the opacity “1” associated with the first opacity function g1 is applied to an image component having a CT value within the range of CT1 to CT2, the first color value function f1 is applied. The density value associated with is given as it is.

Note that the first cross-sectional image data creation process is performed in a coordinate space (U ₁ -U ₂ coordinate system in FIG. 13) configured by CT image data. The created first cross-sectional image data is in a predetermined file format, for example, JPEG (joint photographic experts group), GIF (graphics interchange format), TIFF (tagged image file format), BMP (Microsoft device independent bitmap). , PICT (quickdraw picture), PDF (portable document format), pbm (portable any map file format) and the like are stored in the image data storage unit 12.

<4> First cross-sectional image generation processing is performed to generate a first cross-sectional image G1 (first cross-sectional image generation step; see step S4 in FIG. 8). As for the first slice image G1, the first slice image generation unit 151 (see FIG. 3) of the image generation unit 15 reads the first slice image data stored in the image storage unit 12, and the first slice image G1 It is created by converting the cross-sectional image data into image data corresponding to the coordinate system (X ₁ -X ₂ coordinate system in FIG. 13) of the image display unit 31.

The created first cross-sectional image G1 is displayed in the display area W1 of the image display unit 31 (see FIG. 5). In the first cross-sectional image G1, a region R ₂ (a region constituted by image constituent elements associated with opacity “0” by the first cross-sectional image data creation process) is displayed with a density value “0”. (In FIG. 6, the area of density value “0” is displayed in white, but is actually displayed in black), areas R ₁ and R ₃ (the opacity is obtained by the first cross-sectional image data creation process) A region composed of image components associated with “1”) is displayed in grayscale with density values in the range of “0 to 255”.

  <5> The second color value function creation process is performed to create a second color value function f2 (see FIG. 11) (second color value function creation step; see step S5 in FIG. 8). The second color specification value function g1 is created by the following procedure, for example.

  First, an instruction to create a second color value function f2 by an operator such as a doctor is given via the input device 20 (for example, by a click operation of the mouse 22) in the function creation unit 13 (see FIG. 3). When this instruction is input, the second colorimetric value function creation unit 132 of the function creation unit 13 reads the MRI image data stored in the image data storage unit 12 and the signal intensity carried by the MRI image data. A second color specification value function f2 is provisionally created based on the value distribution, and a graph of the provisionally created second color specification value function f2 is displayed in the display area W4 of the image display unit 31.

The second color value function f2 defines the correspondence between the signal intensity value carried by the MRI image data and the density value of the image when the MRI image data is imaged. For example, FIG. Created in the manner shown. In the example shown in FIG. 11, a density value “0” is associated with a signal intensity value less than H1, and a density value “255” is associated with a signal intensity value greater than H2. Further, the signal intensity values in the range from H1 to H2 are linearly associated with density values from “0 to 255” (so that the slope of the graph is constant). The specific numerical values of H1 and H2 is in the range of H1 or H2 below the signal strength value is set to match the range of the signal intensity values corresponding to the biological tissue located in the region R ₂ of the above .

  Next, the operator determines the suitability of the second color value function f2 based on the provisionally created graph of the second color value function f2 (in order to facilitate this determination, the operator has created the provisional value. A second cross-sectional image to which the second color value function f2 is applied may be generated and displayed in the display area W2). An instruction to adjust the color value function f2 is given.

  This adjustment instruction includes, for example, a numerical value indicating the signal intensity value (H3 in FIG. 11) of the window level WL and a numerical value indicating the window width WW in the graph of the second color value function f2 shown in FIG. This is done by inputting in 21. When this adjustment instruction is input, the second function creation unit 132 of the function creation unit 13 recreates the second color value function f2 in accordance with the adjustment instruction, and the second color specification value function f2 The graph is displayed in the display area W4 of the image display unit 31.

  The operator determines whether the re-created second color value function f2 is appropriate or not. If the operator determines that the second color value function f2 is not appropriate, an instruction to adjust the second color value function f2 is given again. As described above, the adjustment of the second color value function f2 is repeated until the operator determines that the created second color value function f2 is appropriate.

  <6> A second opacity function creation process is performed to create a second opacity function g2 (see FIG. 12) (second opacity function creation step; see step S6 in FIG. 8). The second opacity function g2 is created by the following procedure, for example.

  First, an instruction to the operator to create the second opacity function g2 is sent to the function creation unit 13 (see FIG. 3) of the arithmetic processing device 10 via the input device 20 (for example, by clicking the mouse 22). input. When this instruction is input, the second opacity function creating unit 134 of the function creating unit 13 performs the second based on the second color value function f2 created by the second color value function creating process. The opacity function g2 is provisionally created, and the provisionally created second opacity function g2 graph is displayed in the display area W4 of the image display unit 31.

  The second opacity function g2 defines the correspondence between the signal intensity value carried by the MRI image data and the opacity of the image when the MRI image data is imaged. For example, as shown in FIG. Created in an aspect. In the example shown in FIG. 12, for the signal intensity value within the signal intensity value range (signal intensity value range between H1 and H2) corresponding to the window width WW in the graph of the second color value function f2 described above, Opacity “1” is associated, and opacity “0” corresponds to signal intensity values within other signal intensity value ranges (signal intensity value range less than H1 and signal intensity value range greater than H2) (The lower limit value of the signal intensity value range associated with the opacity “1” is set to a value smaller than H1, or the upper limit value of the signal intensity value range associated with the opacity “1” is set from H2. Or set it to a larger value).

  Next, the operator determines the suitability of the second opacity function g2 based on the temporarily generated graph of the second opacity function g2 (in order to facilitate this determination, the temporarily generated second opacity function g2 A second cross-sectional image to which the opacity function g2 is applied may be generated and displayed in the display area W2). If determined to be inappropriate, the second opacity function g2 is displayed. Instructs to adjust.

  The instruction for this adjustment is, for example, a signal intensity value that is a lower limit value and a signal intensity value that is an upper limit value of the signal intensity value range corresponding to the opacity “1” in the graph of the second opacity function g2 shown in FIG. Is performed by inputting the value using the keyboard 21. When this adjustment instruction is input, the second opacity function creation unit 134 of the function creation unit 13 recreates the second opacity function g2 in accordance with the adjustment instruction, and the second opacity function g2 The graph is displayed in the display area W4 of the image display unit 31.

  The operator determines whether or not the remade second opacity function g2 is appropriate. If the operator determines that the second opacity function g2 is not appropriate, an instruction to adjust the second opacity function g2 is given again. In this manner, the adjustment of the second opacity function g2 is repeated until the operator determines that the created second opacity function g2 is appropriate.

  <7> Second cross-sectional image data creation processing is performed to create second cross-sectional image data (second cross-sectional image data creation step; see step S7 in FIG. 8). As for the second slice image data, the second slice image data creation unit 142 (see FIG. 3) of the image data creation unit 14 reads out the MRI image data stored in the image data storage unit 12, and the MRI image thereof. The data is created by applying the above-described second color value function f2 and second opacity function g2.

  Here, when the second color value function f2 and the second opacity function g2 are applied to the MRI image data, the second color value function f2 and the first opacity are shown in FIG. This means that based on the function g2, the signal intensity value carried by each image component in the MRI image data is converted into a density value. Note that the second color specification value function f2 and the second opacity function g2 are applied in such a manner that they are multiplied by the MRI image data.

  That is, the density value “0” associated with the second color value function f2 and the opacity “corresponding with the second opacity function g2” are associated with the image component carrying a signal intensity value less than H1. A density value “0” (= 0 × 0) multiplied by “0” is given, and a density associated with the second color specification value function f2 is assigned to an image component carrying a signal intensity value exceeding H2. A density value “0” (= 255 × 0) obtained by multiplying the value “255” by the opacity “0” associated by the second opacity function g2 is given. On the other hand, since the opacity “1” associated with the second opacity function g2 is applied to the image component having a signal intensity value in the range of H1 to H2, the second color value function The density value associated with f2 is given as it is.

Note that the second cross-sectional image data creation process is performed in a coordinate space (V ₁ -V ₂ coordinate system in FIG. 13) configured by MRI image data. The created second slice image data is stored in the image data storage unit 12 in a predetermined file format such as JPEG, GIF, TIFF, BMP, PDF, pbm.

<8> A second cross-sectional image generation process is performed to generate a second cross-sectional image G2 (second cross-sectional image generation step; see step S8 in FIG. 8). As for the second slice image G2, the second slice image generation unit 152 (see FIG. 3) of the image generation unit 15 reads out the second slice image data stored in the image storage unit 12, and the second slice image data It is created by converting the cross-sectional image data into image data corresponding to the coordinate system (X ₁ -X ₂ coordinate system) of the image display unit 31.

The created second cross-sectional image G2 is displayed in the display area W2 of the image display unit 31 (see FIG. 6). In the second cross-sectional image G2, the regions R ₁ and R ₃ (regions constituted by image constituent elements associated with the opacity “0” by the second cross-sectional image data creation process) have the density value “0”. (In FIG. 6, the area of the density value “0” is displayed in white, but is actually displayed in black), the area R ₂ (the opacity by the second sectional image data creation process) A region composed of image components associated with “1”) is displayed in grayscale with density values in the range of “0 to 255”.

  <9> Integrated cross-sectional image data creation processing is performed to create integrated cross-sectional image data (integrated cross-sectional image data creation step; see step S9 in FIG. 8). The integrated cross-sectional image data is created by the integrated cross-sectional image data creation unit 143 (see FIG. 3) of the image data creation unit 14 in the following procedure, for example.

First, CT image data and MRI image data stored in the image data storage unit 12 (in this embodiment, the first slice image data is used as CT image data and the second slice image data is used as MRI image data). Are aligned in a common coordinate system (in FIG. 13, the W ₁ -W ₂ coordinate system). This alignment is performed by using coordinate information (U ₁ -U ₂ coordinates) carried by each image component of the first cross-sectional image data using a conventionally known alignment method such as rigid registration or non-rigid registration. System coordinate values) and coordinate information (coordinate values of the V ₁ -V ₂ coordinate system) carried by each image component of the second cross-sectional image data are used as coordinate information (W ₁ -W of the common coordinate system). _This is performed by converting the coordinate values into _two coordinate systems. Note that a U ₁ -U ₂ coordinate system or a V ₁ -V ₂ coordinate system may be used as the common coordinate system.

  Next, the first slice image data and the second slice image data that have been aligned are integrated. The integration of the image data is performed by using a common coordinate system for the density value carried by each image component of the first slice image data and the density value carried by each image component of the second slice image data. This is done by adding together. The created integrated cross-sectional image data is stored in the image data storage unit 12 in a predetermined file format such as JPEG, GIF, TIFF, BMP, PDF, pbm.

<10> An integrated cross-sectional image generation process is performed to generate an integrated cross-sectional image G3 (integrated cross-sectional image generation step; see step S10 in FIG. 8). The integrated cross-sectional image G2 is read by the integrated cross-sectional image generation unit 153 (see FIG. 3) of the image generation unit 15 from the integrated cross-sectional image data stored in the image storage unit 12, and the integrated cross-sectional image data is stored in the image display unit. It is prepared by converting the image data corresponding to the 31 coordinate system (X ₁ -X ₂ coordinate system).

The created integrated cross-sectional image G3 is displayed in the display area W3 of the image display unit 31 (see FIG. 7). This integrated cross-sectional image G3 is an image in which the first cross-sectional image G1 and the second cross-sectional image G2 are superimposed on each other in the common coordinate system, and the regions R ₁ and R ₃ (may be good depending on the MRI image data). Both the region that is difficult to render and the region R ₂ (the region that is difficult to render depending on the CT image data) can be displayed well.

  FIG. 14 shows an application example of the present invention. FIG. 14 shows a CT cross-sectional image of the head generated from the CT image data (FIG. 14A) and an MRI cross-sectional image of the same head generated from the MRI image data (FIG. 14B). FIG. 4 is an integrated cross-sectional image (FIG. 3C) obtained by applying the present invention and integrating a CT cross-sectional image and an MRI cross-sectional image. However, the CT cross-sectional image is an image to which the first color value function is applied but the first opacity function is not applied. Similarly, the MRI cross-sectional image has the second color value function An image that has been applied but the second opacity function has not been applied.

  As shown in FIG. 14, in the CT cross-sectional image, the bone region is well depicted, but the brain parenchyma region is not well depicted. On the other hand, in the MRI cross-sectional image, the brain parenchyma region is well depicted, but the bone region is not well depicted. On the other hand, in the integrated cross-section generated by applying the present invention, both the bone region and the brain parenchyma region are well depicted.

  FIG. 15 shows an integrated cross-sectional image generated by a conventional method as a comparative example. The integrated cross-sectional image by this conventional method is obtained by integrating the CT cross-sectional image shown in FIG. 14A and the MRI cross-sectional image shown in FIG. 14B based on a predetermined blend ratio. Here, the blend ratio is a density value (color value) carried by each image component of the CT cross-sectional image and each image component of the MRI cross-sectional image when the CT cross-sectional image and the MRI cross-sectional image are integrated. The sum ratio with the density value (color value) to be determined is determined. For example, if the blend rate of the CT cross-sectional image is “α” (0 ≦ α ≦ 1), the blend rate of the MRI cross-sectional image is set to “1-α”.

  In the integrated cross-sectional image according to the conventional method shown in FIG. 15, both the bone region and the brain parenchyma region are depicted, but the integrated cross-sectional image according to the present invention shown in FIG. It can be seen that the two regions of the brain parenchyma are better depicted.

  As mentioned above, although one Embodiment of this invention was described, this invention is not limited to the said embodiment, It is possible to change an aspect variously.

  For example, in the above-described embodiment, the first cross-sectional image, the second cross-sectional image, and the integrated cross-sectional image are all achromatic gray images, but these images can also be chromatic color images. It is. Also, one of the first cross-sectional image and the second cross-sectional image may be a gray image, the other may be a color image, and the integrated cross-sectional image may be an image obtained by integrating the gray image and the color image.

  In the case of a color image, a color value function that associates color values (color values) with the original data values of the image data is used. An example of a mode for displaying such a color value function graph is shown in FIG. In the aspect shown in FIG. 16, a color scale is displayed beside the vertical axis indicating the color specification value. This color scale is for visualizing the color values defined by the tristimulus values indicating the mixing ratio of the three primary colors of R, G, and B. For example, the color scale may be the one shown in FIG. it can.

  A color scale CS1 shown in FIG. 17A visualizes color values representing a single color whose brightness (luminance) only changes, and the color scale CS2 shown in FIG. Colorimetric values representing a plurality of colors that change automatically (here, four colors of red, orange, yellow, and green are illustrated) are visualized. When both the first slice image and the second slice image are color images, the color scale applied to the first color value function and the color scale applied to the second color value function are the same color scale. You may make it use, and you may make it use a different color scale.

  The integration of the first cross-sectional image data and the second cross-sectional image data when both the first cross-sectional image and the second cross-sectional image are color images is, for example, each image component of the first cross-sectional image data. A new color value obtained by adding together the color value held by each image component and the color value held by each image component of the second cross-sectional image data (added for each parameter of R, G, B) This can be done by assigning a color value to each image component of the integrated slice image.

  The opacity function of the above embodiment is set so as to associate the opacity of either “0” or “1” with the original data value, but from “0” to “1”. It is also possible to set the opacity function so that an opacity of any value is associated with the original data value.

  Moreover, although the said embodiment demonstrated as an example the case where the 1st cross-sectional image produced | generated based on CT image data and the 2nd cross-sectional image produced | generated based on MRI image data were integrated, this book The invention can be used to integrate various cross-sectional images. For example, the present invention can be similarly applied to a case where MRI images and CT images photographed under different photographing conditions are integrated, or a case where a morphological image such as CT or MRI and a functional image such as PET or SPECT are integrated. Is possible. Further, the present invention can be similarly applied when three or more cross-sectional images are integrated.

DESCRIPTION OF SYMBOLS 1 Medical image generation apparatus 10 Arithmetic processing apparatus 20 Input apparatus 21 Keyboard 22 Mouse 30 Image display apparatus 31 Image display part W1-W4 Display area f1 1st color value function f2 2nd color value function g1 1st non-value Transparency function g2 Second opacity function G1 First cross-sectional image G2 Second cross-sectional image G3 Integrated cross-sectional image CS1, CS2 Color scale R ₁ , R ₂ , R ₃ region

Claims (8)

An integrated cross-sectional image is generated by integrating the first cross-sectional image generated based on the first medical image data and the second cross-sectional image generated based on the second medical image data so as to overlap each other. A medical image generating device for
A first color value function that creates a first color value function that defines the correspondence between the original data value of the first medical image data and the color value when the first cross-sectional image is displayed. Creating means;
A second color value function that creates a second color value function that defines the correspondence between the original data value of the second medical image data and the color value when the second cross-sectional image is displayed. Creating means;
First opacity function creating means for creating a first opacity function that defines the correspondence between the original data value of the first medical image data and the opacity of the first cross-sectional image;
Second opacity function creating means for creating a second opacity function that defines the correspondence between the original data value of the second medical image data and the opacity of the second cross-sectional image;
First cross-sectional image data carrying each information of the color value and the opacity associated with the first color value function and the first opacity function from the first medical image data, respectively. First sectional image data creating means for creating
Second cross-sectional image data carrying each information of the color value and the opacity associated with the second color value function and the second opacity function from the second medical image data, respectively. Second cross-sectional image data creating means for creating
Integrated cross-sectional image data creating means for creating integrated cross-sectional image data by integrating the first cross-sectional image data and the second cross-sectional image data;
A medical image generation apparatus comprising: integrated cross-sectional image generation means for generating the integrated cross-sectional image displayed on a display screen based on the integrated cross-sectional image data.   The medical image generation apparatus according to claim 1, wherein the first medical image data is X-ray CT image data, and the second medical image data is MRI image data.   3. The medical image generation according to claim 1, further comprising an alignment unit configured to align the first medical image data and the second medical image data in a predetermined common coordinate system. apparatus.   Instruction input means for inputting instructions for determining the functions of the first color value function, the second color value function, the first opacity function, and the second opacity function. The first color value function creating means, the second color value function creating means, the first opacity function creating means, and the second opacity function creating means are connected via the instruction input means. 4. The medical image generation apparatus according to claim 1, wherein each of the functions is created based on the instruction input in step S 4.   5. The medical image generation apparatus according to claim 1, further comprising an integrated cross-sectional image data storage unit that stores the integrated cross-sectional image data in a predetermined image file format. 6.   First cross-sectional image generation means for generating the first cross-sectional image displayed on the display screen based on the first cross-sectional image data, and display on the display screen based on the second cross-sectional image data 6. The medical image generation apparatus according to claim 1, further comprising: a second cross-sectional image generation unit configured to generate the second cross-sectional image to be generated.   Generated based on the first cross-sectional image generated based on the first cross-sectional image data, the second cross-sectional image generated based on the second cross-sectional image data, and the integrated cross-sectional image data The medical image generation apparatus according to claim 6, wherein the integrated cross-sectional image is configured to be simultaneously displayed on the display screen. An integrated cross-sectional image is generated by integrating the first cross-sectional image generated based on the first medical image data and the second cross-sectional image generated based on the second medical image data so as to overlap each other. A medical image generation program for performing
A first color value function that creates a first color value function that defines the correspondence between the original data value of the first medical image data and the color value when the first cross-sectional image is displayed. Creation steps,
A second color value function that creates a second color value function that defines the correspondence between the original data value of the second medical image data and the color value when the second cross-sectional image is displayed. Creation steps,
A first opacity function creating step for creating a first opacity function that defines the correspondence between the original data value of the first medical image data and the opacity of the first cross-sectional image;
A second opacity function creating step for creating a second opacity function that defines the correspondence between the original data value of the second medical image data and the opacity of the second cross-sectional image;
First cross-sectional image data carrying each information of the color value and the opacity associated with the first color value function and the first opacity function from the first medical image data, respectively. A first cross-sectional image data creation step for creating
Second cross-sectional image data carrying each information of the color value and the opacity associated with the second color value function and the second opacity function from the second medical image data, respectively. A second sectional image data creation step for creating
An integrated cross-sectional image data creating step for creating integrated cross-sectional image data by integrating the first cross-sectional image data and the second cross-sectional image data;
A medical image generation program that causes a computer to execute an integrated cross-sectional image generation and display step of generating the integrated cross-sectional image displayed on a display screen based on the integrated cross-sectional image data.