JP2012100955A - Medical image display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a medical image display device capable of executing volume rendering (VR) display for MR images simply and easily.SOLUTION: The medical image display device includes an image storing means for storing MR images obtained from an MRI device and medical images obtained from a medical image acquisition device. A readout means reads out the medical imaging and an MR imaging corresponding to it from the image storing means. The first area extraction means extracts an area in the image read out from the readout means. The second area identifying means identifies the part area in the MR image based on the position information about the position which is extracted by the first area extraction means. A setting means sets the setting information based on the pixel value of the part area identified by the second area extraction means. A generation means generates a volume rendering image of the MR image based on the setting information of the opacity. An image display means displays volume rendering image.

Description

  Embodiments described herein relate generally to a medical image display apparatus.

  In a medical institution, information on a tissue in a subject such as a fluoroscopic image, a tomographic image, and a blood flow in the subject is acquired using a medical image acquisition device. Then, a medical image is generated based on the information, and examination and diagnosis are performed using this medical image. Examples of the medical image acquisition apparatus include an X-ray CT (X-ray Computed Tomography) apparatus and an MRI (Magnetic Resonance Imaging) apparatus.

  The X-ray CT apparatus and the MRI apparatus acquire two-dimensional image data (data defined by a two-dimensional plane of xy) and three-dimensional image data (data defined by a three-dimensional space of xyz, also referred to as volume data). It is possible.

  Here, as a method of displaying the three-dimensional image data two-dimensionally (pseudo three-dimensional image display), volume rendering (hereinafter referred to as “VR”) capable of observing the internal state of the display object or the like. Is used).

  In VR, volume data is virtually constructed in a three-dimensional space. This three-dimensional space is based on the coordinate axes (x, y, z). A combination of each coordinate value in the volume data and the scalar quantity at the coordinate is called a voxel. That is, the volume data is formed by a plurality of voxels.

  In VR, an arbitrary viewpoint for a display object is defined, and a projection plane for projecting three-dimensional volume data as a two-dimensional image (pseudo three-dimensional image) from the viewpoint is defined. . A line of sight from the viewpoint toward the projection plane is defined. Then, the gradation level of the pixel on the projection plane is determined based on the voxel value (pixel value in the voxel) on the line of sight from the viewpoint to the projection plane.

  When determining the gradation level on the projection plane, opacity for each voxel value is set. In VR, according to this opacity, the display mode of the object when viewed from an arbitrary viewpoint is determined. That is, it is set how the defined line of sight is transmitted through the object and how the line of sight is reflected when the projection plane is viewed from the defined viewpoint. As a result, a VR image (pseudo three-dimensional image) is expressed.

  In VR, the opacity is set based on each voxel value as described above. The gradation level setting for displaying the VR image is to set opacity setting information (hereinafter sometimes referred to as “opacity curve”) from the window level (Window Level) and the window width (Window Width). Is done. Although there are various definitions for the window level and the window width, in the following embodiments, the “window width” will be described as a range of pixel values (signal intensity) expressed in an opacity scale. Further, the “window level” is described as being the median value of the pixel values (signal intensity) in the range.

JP 2010-148865 A

  Here, the MR signal intensity of the image acquired by the MRI apparatus varies depending on the imaging conditions (slice thickness, imaging time, etc.). Therefore, unlike an X-ray CT apparatus or the like, there is no absolute value (fixed value) for an imaging target such as a brain or blood vessel.

  For this reason, when a desired region in the MR image is displayed in VR, it is necessary to repeatedly set display conditions (such as an opacity curve) and confirm the image and search for an MR signal intensity that suitably displays the region. Therefore, it takes time and effort to create a VR image.

  Therefore, in the embodiment, a medical image display apparatus capable of easily performing VR display of MR images will be described.

  In order to solve the above problem, the medical image display device described in the embodiment stores an MR image acquired by an MRI apparatus and a medical image acquired by a medical image acquisition apparatus of a type different from the MRI apparatus. Image storage means is included. The reading unit reads the medical image and the MR image corresponding to the medical image from the image storage unit. The first area extracting unit extracts an area in the medical image read by the reading unit. The second region specifying unit specifies a partial region in the MR image based on the position information of the region extracted by the first region extracting unit. The setting means sets opacity setting information based on the pixel values of the partial areas specified by the second area extracting means. The generation unit generates a volume rendering image of the MR image based on the opacity setting information. The display means displays a volume rendering image.

It is a figure which shows the structure of the multi-modality apparatus containing the medical image display apparatus which concerns on 1st Embodiment. It is a figure which shows GUI which concerns on 1st Embodiment. It is a figure which shows GUI which concerns on 1st Embodiment. It is a flowchart which shows operation | movement of the medical image display apparatus which concerns on 1st Embodiment. It is a figure which shows the image displayed by the operation | movement which concerns on 1st Embodiment. It is a figure which shows the image displayed by the operation | movement which concerns on 1st Embodiment. It is a figure which shows the image displayed by the operation | movement which concerns on 1st Embodiment. It is a figure which shows the image displayed by the operation | movement which concerns on 1st Embodiment. It is a figure which shows the image displayed by the operation | movement which concerns on 1st Embodiment. It is a figure which shows the image displayed by the operation | movement which concerns on 1st Embodiment. It is a figure which shows the opacity curve setting method which concerns on 1st Embodiment. It is a figure which shows the structure of the multi-modality apparatus containing the medical image display apparatus which concerns on 2nd Embodiment. It is a figure which shows the opacity curve setting method which concerns on 2nd Embodiment. It is a flowchart which shows operation | movement of the medical image display apparatus which concerns on 2nd Embodiment. It is a figure which shows the image displayed by the operation | movement which concerns on 2nd Embodiment. It is a figure which shows the image displayed by the operation | movement which concerns on 2nd Embodiment.

(First embodiment)
The medical image display apparatus according to this embodiment will be described with reference to FIGS. Note that “image” in the present embodiment includes “image data”.

  FIG. 1 is a diagram illustrating a configuration of a multi-modality apparatus including a medical image display apparatus 3 according to the present embodiment.

  A “multi-modality device” is a device in which a plurality of medical image acquisition devices (modalities) are systematically coupled. For example, it is an apparatus that centrally manages images from different medical image acquisition apparatuses (X-ray CT apparatus, MRI apparatus, etc.) and efficiently manages and browses multiple types of images. In the present embodiment, a configuration using the X-ray CT apparatus 1 and the MRI apparatus 2 as a medical image acquisition apparatus will be described.

  The multi-modality apparatus has an X-ray CT apparatus 1, an MRI apparatus 2, and a medical image display apparatus 3.

  The X-ray CT apparatus 1 is an apparatus that scans a subject using X-rays and acquires a tomographic image thereof. The acquired tomographic image is sent to the storage unit 31 (described later).

  The MRI apparatus 2 is an apparatus that images a subject using magnetic resonance. The acquired image is sent to the storage unit 31 (described later).

  The medical image display device 3 includes a storage unit 31, a CPU 32, an operation unit 33, and a display unit 34 (display means). The medical image display device 3 is composed of a PC, for example.

  The storage unit 31 has a function as an image storage unit 31 a (image storage unit) that stores images acquired by the X-ray CT apparatus 1 and the MRI apparatus 2. In the present embodiment, the storage unit 31 is provided in the medical image display apparatus 3 and stores images obtained by imaging the same part (for example, the brain) of a subject with the X-ray CT apparatus 1 and the MRI apparatus 2, respectively.

  Note that the storage unit 31 does not have to be provided in the medical image display device 3. For example, it may be disposed as an external device of the medical image display apparatus 3 or may be provided in each of the X-ray CT apparatus 1 and the MRI apparatus 2.

  In this embodiment, the CPU 32 includes a reading unit 321 (reading unit), a first region extracting unit 322 (first region extracting unit), a superimposing unit 323 (superimposing unit), a correcting unit 324 (correcting unit), and a second region specifying unit. 325 (second region specifying means), a signal intensity acquisition unit 326 (signal intensity acquisition means), a setting unit 327 (setting means), and a generation unit 328 (generation means).

  The reading unit 321 has a function of reading a desired X-ray CT image and an MR image corresponding to the same subject and the same part as the X-ray CT image based on an instruction from the operation unit 33 or the like. An MR image corresponding to a desired X-ray CT image is specified using coordinate values in each image. The identity of the subject can be determined by the patient ID or the like.

  The first region extraction unit 322 has a function of extracting a region in the medical image read by the reading unit 321. In the present embodiment, the medical image is a tomographic image of the subject acquired by the X-ray CT apparatus 1. In the present embodiment, the region is a region in which, for example, a heart or a brain blood vessel can be specified. The first region extraction unit 322 performs region extraction processing based on, for example, an input from the operation unit 33 (details will be described later). Input from the operation unit 33 can also be performed using a region extraction GUI 331 (described later).

  The region extraction process can be performed automatically or manually. When performing automatically, area extraction is performed by executing a predetermined automatic extraction algorithm based on an input from the operation unit 33. As the automatic extraction algorithm, a known method (for example, region growing method) is used. On the other hand, when performing manually, the operator performs an extraction operation on the image displayed on the display unit 34 while performing segmentation with the operation unit 33 (such as a mouse).

  The superimposing unit 323 has a function of superimposing the region extracted by the first region extracting unit 322 on the MR image corresponding to the X-ray CT image. This MR image is an MR image read by the reading unit 321 in association with the X-ray CT image.

  The correction unit 324 has a function of correcting the position and size of the superimposed region. The correction by the correction unit 324 is automatically performed by a known correction method such as affine transformation based on an input from the operation unit 33 (details will be described later). Alternatively, the correction process by the correction unit 324 may be executed based on the result of manual input (for example, drag and drop by the mouse) on the image via the operation unit 33 by the operator. The input from the operation unit 33 can also be performed using a correction GUI 332 (described later).

  The second region specifying unit 325 has a function of specifying a partial region in the MR image read by the reading unit 321 based on the position information of the region extracted by the first region extracting unit 322. More specifically, the second region specifying unit 325 has a function of specifying pixels in the contour of the partial region in the MR image corresponding to the region corrected by the correcting unit 324. The “partial region in the MR image” is a specific region in the MR image (region corresponding to a region in the X-ray CT image of the same part as the MR image (region extracted by the first region extraction unit 322)) Means. The “partial area outline” means a boundary part that divides the partial area and other areas.

  The signal strength acquisition unit 326 has a function of acquiring the signal strength at the pixel specified by the second region specifying unit 325. In the present embodiment, since the pixel specified by the second region specifying unit 325 is a pixel of the MR image, the signal intensity acquisition unit 326 acquires the MR signal intensity at each pixel.

  The setting unit 327 has a function of setting an opacity curve (opacity setting information) based on the signal intensity acquired by the signal intensity acquisition unit 326. A specific method for setting the opacity curve will be described later.

  The generation unit 328 has a function of generating an MR image VR image based on the opacity curve set by the setting unit 327. Since a VR image is generated based on a known method, detailed description thereof is omitted.

  The operation unit 33 includes an arbitrary input device such as a keyboard and a mouse, and an operation device. In response to an input instruction from the operation unit 33, for example, the operation of the medical image display device 3 is executed. The operation unit 33 can execute an operation input via a GUI (Graphical User Interface) as shown in FIGS. Alternatively, a dedicated control panel can be used.

  The display unit 34 includes an arbitrary display device such as an LCD. The display unit 34 displays the VR image generated by the generation unit 328 and the like.

  FIG. 2 is an example of a region extraction GUI 331 for region extraction. The region extraction GUI 331 is displayed on the display unit 34, for example. Based on the input from the region extraction GUI 331, the first region extraction unit 322 executes region extraction processing.

  The region extraction GUI 331 includes a manual / auto unit 3311 that selects whether an operation of extracting a region is performed manually or automatically. In the present embodiment, the Manual / Auto unit 3311 has a Manual icon 3311a and an Auto icon 3311b.

  The region extraction GUI 331 includes an algorithm selection unit 3312 for selecting an extraction algorithm that performs automatic extraction when Auto is selected. In this embodiment, the algorithm selection unit 3312 includes a Brain icon 3312a selected during automatic brain extraction, a Heart icon 3312b selected during automatic heart extraction, and a Thorax icon selected during automatic chest extraction. 3312c and an Abdomen icon 3312d that is selected when the abdomen is automatically extracted.

  The extraction algorithm selected by the algorithm selection unit 3312 is stored in the storage unit 31 provided in the medical image display device 3, for example. That is, in the present embodiment, the storage unit 31 has a function as the algorithm storage unit 31b. Note that the algorithm storage unit 31b may be provided separately from the storage unit 31.

  The region extraction GUI 331 includes a type selection unit 3313 that selects the type of medical image from which a region is to be extracted. In this embodiment, the type selection unit 3313 includes a CT icon 3313a for selecting an X-ray CT image, an MRI icon 3313b for selecting an MR image, an UL icon 3313c for selecting an ultrasound image, and an Other icon 3313d for selecting another image. Have

  FIG. 3 is an example of a correction GUI 332 that corrects a region. The correction GUI 332 is displayed on the display unit 34, for example. Based on the input from the correction GUI 332, the correction unit 324 executes correction processing for the position and size of the superimposed region.

  The correction GUI 332 is an adjustment unit that adjusts the position and size of the region so that the region extracted by the first region extraction unit 322 and the partial region in the MR image do not match with the partial region. 3321. The adjustment unit 3321 includes a Move icon 3321a for designating an operation for moving the area, a Dilate icon 3321b for designating an operation for expanding the area, and an Erode icon 3321c for designating an operation for reducing the area.

  For example, when it is desired to move a certain area with respect to the partial area, the operator selects the Move icon 3321a via the operation unit 33. Based on this selection operation, the region can be moved on the MR image. Therefore, correction can be performed by the operator moving the area via the operation unit 33.

  The correction GUI 332 includes a determination unit 3322 (Deceed icon) that determines the correction processing of the region. For example, when the above-described Move operation is completed, the content of the correction operation is determined by the operator selecting the Decide icon.

  Next, the operation of the medical image display apparatus 3 according to this embodiment will be described with reference to FIGS. In this embodiment, an example in which VR display is performed on a brain image will be described.

  When the MR image is displayed in VR using the medical image display apparatus 3 of the present embodiment, the reading unit 321 first corresponds to the X-ray CT image stored in the storage unit 31 and the corresponding one based on the input instruction from the operation unit 33. The MR image is read (S1). The MR image corresponding to the X-ray CT image is read out as follows, for example.

  When an X-ray CT image is selected by the operator, the readout unit 321 performs a process of reading out an image having the same part and the same coordinate value from the MR image of the subject as a “corresponding MR image”.

  By this reading process, in this embodiment, the X-ray CT image I1 as shown in FIG. 5A and the MR image I2 as shown in FIG. 5B are displayed in parallel on the display unit 34.

  Next, the first region extraction unit 322 performs a process of extracting the region α in the X-ray CT image I1 acquired in S1 (S2). In the present embodiment, the extraction of the region α is executed as follows based on an instruction from the region extraction GUI 331 shown in FIG.

  First, the operator uses the CT icon 3313a to select the X-ray CT image I1 as an image to be subjected to region extraction processing. Further, the operator selects whether the region α is automatically or manually extracted from the X-ray CT image I1 displayed on the display unit 34 by using the Manual / Auto unit 3311 of the region extraction GUI 331.

  Here, when the operator selects automatic extraction (when the Auto icon 3311b is selected), the operator next extracts an area α from the X-ray CT image I1 displayed on the display unit 24 by the algorithm selection unit 3312. Select the algorithm to do. In this embodiment, since a region is extracted from the brain X-ray CT image I1, the Brain icon 3312a is selected.

  Based on the selected algorithm, the first region extraction unit 322 extracts the region α on the X-ray CT image I1. By this extraction process, in the present embodiment, an X-ray CT image I1 as shown in FIG. 5C is displayed on the display unit 34. Here, in FIG. 5C, a region indicated by a broken line and filled with diagonal lines is a region α.

  Next, the superimposing unit 323 performs a process of superimposing the region α extracted in S2 on the MR image I2 read out in S1 (S3). Specifically, as shown in FIG. 5D, the image of the region α extracted in S2 is superimposed and displayed on the two-dimensionally displayed MR image I2.

  Next, the correcting unit 324 performs a process of correcting the position and size of the region α so that the region α superimposed in S3 overlaps the corresponding position in the MR image I2 (S4). In the present embodiment, the correction is executed based on an instruction from the correction GUI 332 shown in FIG.

  In the image superimposed in S3, the region α may be misaligned with respect to the MR image I2 as shown in FIG. 5D. In such a case, the operator selects the Move icon 3321a of the correction GUI 332 in FIG. When the Move icon 3321a is selected, the operator can move the position and orientation of the region α on the MR image I2 by the operation unit 33. The operator moves the MR image I2 so that the region α overlaps, and then selects the determination unit 3322 of the correction GUI 332 to determine the region (partial region) of the MR image I2. This image is displayed on the display unit 34 as shown in FIG. 5E, for example.

  In the present embodiment, the correction process in S4 is described as being performed manually. However, the correction process can be automatically executed using a known correction algorithm (for example, pattern matching).

  Next, the second area specifying unit 325 performs processing for specifying pixels in the contour of the partial area in the MR image I2 corresponding to the area α corrected in S4 (S5). Specifically, a process of specifying pixels only in the contour portion of the partial region in the MR image I2 corresponding to the region α corrected in S4 is performed. An image as shown in FIG. 5F is displayed on the display unit 34 by S5. Here, in FIG. 5F, a portion indicated by a broken line is a contour portion β.

  Next, the signal strength acquisition unit 326 performs processing for acquiring the MR signal strength for each pixel of the contour portion β specified in S5 (S6). In the present embodiment, the acquired MR signal intensity is histogrammed by the signal intensity acquisition unit 326.

  Next, the setting unit 327 performs processing for setting an opacity curve based on the signal intensity (signal intensity histogram) acquired in S6 (S7).

  FIG. 6 is a graph in which the vertical axis represents opacity (opacity) and the horizontal axis represents MR signal intensity. The broken line graph is a histogram of the signal intensity of the entire MR image.

  The graph of the MR signal intensity histogram of the partial region contour acquired in S6 is as shown by the solid line H1 in FIG. The setting unit 327 calculates the maximum value and the minimum value of the MR signal intensity in this graph. Then, the setting unit 327 obtains the window level and the window width based on the maximum value / minimum value. The window level is obtained by dividing the sum of the maximum and minimum values by 2. The window width is obtained by taking the difference between the maximum value and the minimum value.

  An opacity curve is set based on the window level and window width obtained by the setting unit 327. In the present embodiment, for example, an opacity curve O1 as shown by a solid line in FIG. 6 is set.

  Then, the generation unit 328 performs processing for generating a VR image of the MR image I2 based on the opacity curve O1 set in S7 (S8). The VR image generated by the generation unit 328 is displayed on the display unit 34 (S9).

(Operational effects of the first embodiment)
According to the configuration of the first embodiment, the first region extraction unit 322 extracts the region of the X-ray CT image acquired by the X-ray CT apparatus 1 (medical image acquisition device). Further, the region where the superimposing unit 323 is extracted is superimposed on the MR image corresponding to the X-ray CT image. The correction unit 324 corrects the position and / or size of the superimposed region. In addition, the second region specifying unit 325 specifies pixels in the contour of the partial region in the MR image. The signal intensity acquisition unit 326 acquires the signal intensity of the pixel specified by the second region specifying unit 325. The setting unit 327 sets an opacity curve based on the acquired signal strength. Then, the generation unit 328 generates a VR image of the MR image based on the opacity curve and displays it on the display unit 34.

  According to the opacity curve set by the setting unit 327, the outline (outer periphery) of the partial area is displayed opaquely, and the other areas are displayed transparently. Therefore, when a VR image is generated based on the opacity curve, only the contour portion of the partial region can be observed as a pseudo three-dimensional image.

  Therefore, it is possible to easily generate and display a VR image even for an MR image that does not have an absolute value for an imaging target such as a brain or blood vessel.

  Moreover, according to the structure of 1st Embodiment, it has the algorithm memory | storage part which has several extraction algorithm for area | region extraction. Further, based on the selection result using the region extraction GUI 331, the first region extraction unit 322 reads an extraction algorithm corresponding to the selection from the algorithm storage unit, and executes a process of extracting a region. Further, according to the configuration of the first embodiment, the correction unit 324 performs a process of correcting a region superimposed on the MR image (a region extracted from the X-ray CT image) based on the selection result using the correction GUI 332. Execute.

  Thus, the operability of the medical image display apparatus 3 is improved by using various GUIs. Therefore, it is possible to easily generate and display a VR image for an MR image.

(Modification of the first embodiment)
The opacity curve is not limited to the method of the first embodiment as long as it is set based on the MR signal intensity in the contour of the partial region of the MR image.

  For example, the setting unit 327 calculates the average value (μ) and standard deviation (δ) of the MR signal intensity at the contour. Then, the setting unit 327 can obtain the window level and the window width based on the average value and the standard deviation.

  In the first embodiment, the shape of the opacity curve is set to a rectangle as shown in FIG. 6, but the shape is not limited to a rectangle as long as only the contour of the partial area can be displayed in VR.

(Second Embodiment)
Next, a medical image display apparatus according to the second embodiment will be described with reference to FIGS. Note that “image” in the present embodiment includes “image data”. Detailed description of the same configuration as that of the first embodiment is omitted.

  In the configuration of the first embodiment, a VR image is generated based on the MR image of FIG. 5F. Here, in the MR image of FIG. 5F, the image of the subject is also present outside the outline of the partial region. Therefore, when the MR signal intensity of a pixel included in this region (region outside the contour of the partial region) is between the maximum value and the minimum value of the MR signal strength of the partial region, the opacity curve in FIG. Become. Therefore, areas other than the partial areas are also displayed as VR images. That is, in the configuration of the first embodiment, there are cases where it is not possible to display only the area that is actually desired to be displayed in VR. In the second embodiment, a configuration capable of performing VR display of only a partial region even in such a case will be described.

  FIG. 7 is a diagram illustrating a configuration of a multi-modality device including the medical image display device 3 according to the present embodiment. In the present embodiment, a configuration using the X-ray CT apparatus 1 and the MRI apparatus 2 as a medical image acquisition apparatus will be described.

  In this embodiment, the CPU 32 includes a reading unit 321 (reading unit), a first region extracting unit 322 (first region extracting unit), a superimposing unit 323 (superimposing unit), a correcting unit 324 (correcting unit), and a second region specifying unit. 325 (second area specifying means), signal intensity acquisition section 326 (signal intensity acquisition means), setting section 327 (setting means), and generation section 328 (generation means), as well as a partial area extraction section 329 (partial area extraction means) ).

  The partial area extraction unit 329 has a function of extracting a partial area from the MR image based on the pixels in the outline of the partial area specified by the second area specifying unit 325. In this extraction process, for example, a process of changing the value of a pixel located outside the pixel in the outline of the partial region to a value that is not subjected to image processing (for example, a padding value) is performed.

  The setting unit 327 in the present embodiment has a function of setting a predetermined opacity curve for the partial region extracted by the partial region extraction unit 329. The partial region extraction unit 329 displays only the partial region image in the MR image. Accordingly, since an image outside the partial region does not affect the VR image display, an opacity curve β is set such that the opacity is 1 (voxel is opaque, see FIG. 8) for all MR signal intensities. do it. A solid line H2 in FIG. 8 is a graph based on a histogram of the MR signal intensity in the partial region. The broken line graph is a histogram of the signal intensity of the entire MR image.

  Next, the operation of the medical image display apparatus 3 in this embodiment will be described with reference to FIGS. The detailed processing of S10 to S14 is the same as the processing of S1 to S5 of the first embodiment, and thus detailed description thereof is omitted.

  When MR images are displayed in VR using the medical image display device 3 of the present embodiment, the reading unit 321 corresponds to the X-ray CT image I1 stored in the storage unit 31 and the corresponding one based on an input instruction from the operation unit 33. The MR image I2 is read (S10).

  Next, the first area extraction unit 322 performs a process of extracting the area α in the X-ray CT image I1 acquired in S10 (S11).

  Next, the superimposing unit 323 performs a process of superimposing the region α extracted in S11 on the MR image I2 read out in S10 (S12).

  Next, the correction unit 324 performs a process of correcting the position and size of the region α so that the region α superimposed in S12 overlaps the corresponding position in the MR image I2 (S13).

  Next, the second region specifying unit 325 performs processing for specifying pixels in the contour of the partial region in the MR image I2 corresponding to the region α corrected in S13 (S14).

  Next, the partial region extraction unit 329 performs processing for extracting the partial region specified in S14 from the MR image I2 (S15). Specifically, as shown in FIG. 10A, the operator instructs the partial area extraction via the operation unit 33 or the like to the MR image I2 on which the contour part β of the partial area is displayed. Based on the instruction, the partial region extraction unit 329 executes processing for extracting only the partial region from the MR image I2. As a result of this processing, an MR image I3 (an image in which only a partial area is displayed) as shown in FIG. 10B is displayed on the display unit 34.

  Next, the signal strength acquisition unit 326 performs processing for acquiring the MR signal strength of the pixel specified in S14 (S16). In the present embodiment, the acquired MR signal intensity is histogrammed by the signal intensity acquisition unit 326. Note that S15 and S16 may be executed at the same time, or may be executed by changing the order.

  Next, the setting unit 327 performs a process of setting a predetermined opacity curve used for the partial region extracted in S15 (S17). As described above, in the present embodiment, an opacity curve O2 (see FIG. 8) having an opacity of 1 is set.

  Then, the generation unit 328 performs processing for generating a VR image of the MR image I3 based on the opacity curve O2 set in S17 (S18). The VR image generated by the generation unit 328 is displayed on the display unit 34 (S19).

(Operational effect of the second embodiment)
According to the configuration of the second embodiment, the first region extraction unit 322 extracts the region of the X-ray CT image acquired by the X-ray CT apparatus 1 (medical image acquisition device). Further, the region where the superimposing unit 323 is extracted is superimposed on the MR image corresponding to the X-ray CT image. The correction unit 324 corrects the position and / or size of the superimposed region. In addition, the second region specifying unit 325 specifies pixels in the contour of the partial region in the MR image. Further, the partial area extraction unit 329 extracts the specified partial area from the MR image. The signal intensity acquisition unit 326 acquires the signal intensity of the pixel specified by the second region specifying unit 325. The setting unit 327 sets a predetermined opacity curve. Then, the generation unit 328 generates a VR image of the MR image based on the opacity curve and displays it on the display unit 34.

  According to the opacity curve set by the setting unit 327, only the outline (outer periphery) of the partial region is displayed in an opaque state. Therefore, when a VR image is generated based on the opacity curve, only a partial region can be observed as a pseudo three-dimensional image.

  Therefore, it is possible to easily generate and display a VR image even for an MR image that does not have an absolute value for an imaging target such as a brain or blood vessel.

(Modification of the second embodiment)
In the second embodiment, only the partial area extracted by the partial area extraction unit 329 is displayed based on a predetermined opacity curve.

  On the other hand, by setting different opacity curves in the setting unit 327 for MR image regions (regions other than the partial regions) that have not been extracted by the partial region extraction unit 329, the partial region and the other regions are displayed differently. VR display can be performed in this manner.

  These different VR images may be displayed in parallel or displayed in a superimposed manner. For example, superimposed display is performed such that the opacity of the partial area is 1 (opaque) and the opacity of other areas is 0.2 (almost transparent).

  Further, the opacity of other areas may be adjusted arbitrarily. For example, there may be a case where it is desired to clearly display an area other than the partial area, for example, when confirming how the other area is formed with respect to the partial area. In such a case, it is possible to confirm an area other than the partial area by adjusting the opacity curve by making an input from the operation unit 33 (making the opacity curve close to 1).

(Modification common to the first embodiment and the second embodiment)
In the embodiment, the configuration using the X-ray CT apparatus 1 as a medical image acquisition apparatus has been described. However, the present invention is not limited to this as long as the apparatus can acquire an image from which a specific region can be extracted.

  In an MRI apparatus, a T1-weighted image and a T2-weighted image are usually taken as a set. For example, at this time, it may be difficult to determine a specific area in the T1-weighted image and to determine the specific area in the T2-weighted image. At this time, the specific region is extracted from the T1-weighted image, and based on the region, the same processing as in the first embodiment or the second embodiment is performed on the T2-weighted image. VR display of (image) is possible. That is, an MRI apparatus can be included as a medical image acquisition apparatus.

  In the embodiment, the MRI apparatus and the X-ray CT apparatus are described separately as a multi-modality configuration having a medical image display apparatus, but the present invention is not limited to this.

  For example, the MRI apparatus 2 itself can have the function of the medical image display apparatus 3. In this case, the MRI apparatus 2 stores the medical image photographed by the X-ray CT apparatus 1, and executes the processing using the MR image photographed by the own apparatus and the medical image, so that the VR display similar to the embodiment is performed. It becomes possible.

  In addition, it is possible to improve the accuracy of specifying a partial region (contour portion) by performing correction processing on the MR image corresponding to each X-ray CT image and specifying the pixels constituting the contour of the partial region from the result. Become.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 1 X-ray CT apparatus 2 MRI apparatus 3 Medical image display apparatus 31 Memory | storage part 31a Image memory | storage part 31b Algorithm memory | storage part 32 CPU
33 Operation Unit 34 Display Unit 321 Reading Unit 322 First Region Extraction Unit 323 Superimposition Unit 324 Correction Unit 325 Second Region Identification Unit 326 Signal Strength Acquisition Unit 327 Setting Unit 328 Generation Unit

Claims (7)

Image storage means for storing MR images acquired by the MRI apparatus and medical images acquired by a different type of medical image acquisition apparatus from the MRI apparatus;
Reading means for reading out a medical image and an MR image corresponding to the medical image from the image storage means;
First area extraction means for extracting an area in the medical image read by the reading means;
Second area specifying means for specifying a partial area in the MR image based on position information of the area extracted by the first area extracting means;
Setting means for setting opacity setting information based on the pixel values of the partial areas specified by the second area specifying means;
Generating means for generating a volume rendering image of the MR image based on the setting information of the opacity;
Display means for displaying the volume rendering image;
A medical image display device comprising: Superimposing means for superimposing the area extracted by the first area extracting means on an MR image corresponding to the medical image from which the area is extracted;
Correction means for correcting the position and / or size of the superimposed region;
Further comprising
2. The medical image display device according to claim 1, wherein the second region specifying unit specifies a pixel in a contour of a partial region in the MR image corresponding to the region corrected by the correcting unit. Algorithm storage means having a plurality of extraction algorithms for extracting the area extracted by the first area extraction means;
A region extraction GUI displayed on the display means for selecting an arbitrary extraction algorithm from the plurality of extraction algorithms;
The first area extraction unit reads out an extraction algorithm corresponding to the selection from the algorithm storage unit based on a selection result using the area extraction GUI, and executes a process of extracting the area. The medical image display apparatus according to claim 1 or 2. A correction GUI displayed on the display means for selecting a correction operation;
The medical image display apparatus according to claim 2, wherein the correction unit executes a process of correcting the superimposed region based on a selection result using the correction GUI. Image storage means for storing MR images acquired by the MRI apparatus and medical images acquired by a different type of medical image acquisition apparatus from the MRI apparatus;
Reading means for reading out a medical image and an MR image corresponding to the medical image from the image storage means;
First area extraction means for extracting an area in the medical image read by the reading means;
Second area specifying means for specifying a partial area in the MR image based on position information of the area extracted by the first area extracting means;
A partial region extracting means for extracting the partial region from the MR image based on the pixels in the contour of the partial region identified by the second region identifying means;
Setting means for setting opacity setting information based on the value of the pixel in the partial area extracted by the partial area extraction unit;
Generating means for generating a volume rendering image of the MR image based on the setting information of the opacity;
Display means for displaying the volume rendering image;
A medical image display device comprising: Superimposing means for superimposing the area extracted by the first area extracting means on an MR image corresponding to the medical image from which the area is extracted;
Correction means for correcting the position and / or size of the superimposed region;
Further comprising
6. The medical image display apparatus according to claim 5, wherein the second region specifying unit specifies a pixel in a contour of a partial region in the MR image corresponding to the region corrected by the correcting unit.   The medical image display apparatus according to claim 1, wherein the medical image acquisition apparatus is an X-ray CT apparatus.

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