JP2011206240A - Medical image display device, method, and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To distinguish an angiographic portion and a calcification portion by using an image obtained by dual energy imaging.SOLUTION: A first image-generating part 6 generates a first bone-removed image G1 from which a bone portion and the calcification portion are removed and which includes only the angiographic portion. A second image-generating part 8 generates a second bone-removed image G2 from which only the bone portion is removed but which includes the angiographic portion and the calcification portion. A display control part 10 comparably displays the first and second bone-removed images G1, G2 on a display 12.

Description

  The present invention relates to a medical image display apparatus and method for displaying a medical image acquired by dual energy imaging, and a program.

  In recent years, due to advances in medical equipment (for example, multi-detector CT), high-quality three-dimensional images have been used for image diagnosis. Here, since a three-dimensional image is composed of a large number of two-dimensional tomographic images and has a large amount of information, it may take time for a doctor to find and diagnose a desired observation site. Accordingly, the structure of interest is recognized by using a method such as a maximum value projection method (MIP method) and a minimum value projection method (MinIP method) from a three-dimensional image including the structure of interest, for example. By creating a 3D image and performing MIP display, etc., performing 3D volume rendering (VR) display, or performing CPR (Curved Planer Reconstruction) display (ie, pseudo 3D display) Various techniques for improving the visibility of the entire structure and also the lesions included in the structure have been proposed.

  On the other hand, as a method for separating materials in a tomographic image of a subject, a method using dual energy imaging is known. This technique is a technique that utilizes the characteristics of a substance in which the X-ray absorption rate of the substance differs depending not only on the type of substance but also on the energy of the X-ray, and the energy distribution in the CT apparatus is different from each other. This is a technique for separating a substance in a tomographic image by photographing a subject using types of X-rays and comparing pixel values (CT values) of corresponding pixels between two types of obtained tomographic images. For example, in Patent Document 1, a high energy tomographic image and a low energy tomographic image are obtained by performing dual energy imaging by switching the voltage of an X-ray tube between a high voltage and a low voltage. A method for separating substances included in an image based on a ratio of corresponding pixel values in a tomographic image has been proposed. In addition, it is also possible to isolate | separate the site | part contained in a tomographic image by weighting and subtracting the high energy tomographic image and low energy tomographic image acquired by performing dual energy imaging | photography.

  Further, Non-Patent Document 1 discloses an angiographic tomographic image of the head and neck by using a material separation technique using a high-energy tomographic image and a low-energy tomographic image obtained by performing dual energy imaging. Have proposed a method of acquiring an image in which an angiographic part is extracted by removing a bone part.

  On the other hand, the angiographic part on the tomographic image often has a uniform and high image density, but since the cancellous bone exists in the center of the bone, the bone part on the tomographic image has an uneven image density. It is common to have. Therefore, based on the uniformity of image density in the tomographic image, there is also a method of separating a bone part, which is a tissue having a non-uniform density, and an angiographic part, which is a tissue having a uniform density, using a uniform filter. It has been proposed (see Patent Document 2). Also by the technique described in Patent Document 2, it is possible to remove the bone portion having a non-uniform density from the tomographic image and obtain an image in which the angiographic portion is extracted.

JP 2009-178493 A JP 2009-45110 A

Yoshiyuki Watanabe, “Dual Energy Imaging-Clinical Applications in the Head and Neck Area”, Inner Vision, November 2009, Supplement

  By the way, when diagnosing stenosis or the like of a blood vessel using a tomographic image, it is important to observe not only the state where the blood vessel is stenotic but also the state of calcification of the blood vessel wall. Here, the calcified portion contains calcium similar to bone. For this reason, when extracting an angiographic part using the high energy tomographic image and the low energy tomographic image acquired by the dual energy imaging | photography described in the patent document 1 and the nonpatent literature 1, the calcified part is also removed with the bone part. Is done. As a result, in the image obtained by extracting the angiographic portion, the state where the blood vessel is narrowed can be observed, but the state of calcification of the blood vessel wall cannot be observed. On the other hand, in the method described in Patent Document 2, only the bone portion can be extracted by the uniform filter, and the calcified portion cannot be extracted. For this reason, in the acquired image, the angiographic portion and the calcification of the blood vessel wall cannot be distinguished.

  The present invention has been made in view of the above circumstances, and an object thereof is to enable an angiographic portion and a calcified portion to be separated using an image acquired by dual energy imaging.

The medical image display apparatus according to the present invention uses the first and second medical images based on the first and second medical images acquired by performing dual energy imaging of a subject using two types of radiation having different energies. First image generating means for generating a first bone removal image from which a bone part included in the medical image is removed;
Recognizing a tissue included in at least one of the first and second medical images or a composite image generated from the first and second medical images, and based on the recognition result, the first And second image generation means for generating a second bone-removed image obtained by removing a bone part included in the second medical image or the composite image;
Display control means for displaying the first and second bone removal images in a comparable manner is provided.

The medical image display device according to the present invention further includes third image generation means for generating a calcified image obtained by extracting a calcified portion included in the first and second medical images.
The display control unit may be a unit that displays the calcified portion so as to be visible in any one of the first and second bone removal images based on the calcified image.

  Note that the calcification image can be generated, for example, by weighting and subtracting the first bone removal image and the second bone removal image.

  In the medical image display apparatus according to the present invention, the display control means may be means for displaying the first and second bone removal images in a pseudo three-dimensional manner.

The medical image display method according to the present invention uses the first and second medical images based on the first and second medical images acquired by performing dual energy imaging of a subject using two types of radiation having different energies. Generating a first bone-removed image in which a bone portion included in the medical image is removed;
Recognizing a tissue included in at least one of the first and second medical images or a composite image generated from the first and second medical images, and based on the recognition result, the first And generating a second bone-removed image in which a bone part included in the second medical image or the composite image is removed;
And displaying the first and second bone removal images in a switchable manner.

  In addition, you may provide as a program for making a computer perform the medical image display method by this invention.

  According to the present invention, the first and second medical images are included based on the first and second medical images acquired by performing dual energy imaging of the subject using two types of radiation having different energies. A first bone removal image from which the bone portion to be removed is removed is generated. In addition, a tissue included in at least one of the first and second medical images or a composite image generated from the first and second medical images is recognized, and the first and second are based on the recognition result. A second bone-removed image is generated by removing the bone portion included in the medical image or composite image. Here, although the calcified portion is removed together with the bone portion from the first bone removed image, only the bone portion is removed from the second bone removed image, and the calcified portion remains. . For this reason, by displaying the first and second bone removal images in a comparable manner, the angiographic portion and the calcified portion can be separated. Therefore, it is possible to accurately diagnose blood vessels by observing the angiographic portion and the calcified portion.

  Further, by generating a calcified image obtained by extracting the calcified portion included in the first and second medical images, and displaying the calcified portion in either of the first and second bone removal images so as to be visible. Since the calcified portion can be recognized more reliably, the blood vessel diagnosis by observing the angiographic portion and the calcified portion can be performed with higher accuracy.

1 is a schematic block diagram showing the configuration of a medical image display device according to a first embodiment of the present invention. Schematic block diagram showing the configuration of an X-ray tomography apparatus A diagram showing a histogram of pixel value ratios A diagram showing a two-dimensional distribution of pixel values The figure which shows a 1st bone removal image The figure which shows a 2nd bone removal image The flowchart which shows the process performed in 1st Embodiment. The figure which shows the display screen of the 1st and 2nd bone removal image in 1st Embodiment. The schematic block diagram which shows the structure of the medical image display apparatus by the 2nd Embodiment of this invention. The figure for demonstrating the production | generation of a calcification image The flowchart which shows the process performed in 2nd Embodiment. The figure which shows the display screen of the 1st and 2nd bone removal image in 2nd Embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic block diagram showing the configuration of a medical image display apparatus according to the first embodiment of the present invention. The configuration of the medical image display device 1 shown in FIG. 1 is realized by executing a medical image display program read into the auxiliary storage device on a computer. At this time, this medical image display program is stored in a storage medium such as a CD-ROM or distributed via a network such as the Internet and installed in a computer.

  The medical image display apparatus 1 according to the first embodiment includes an image acquisition unit 2, a storage unit 4, a first image generation unit 6, a second image generation unit 8, a display control unit 10, a display unit 12, and an input unit 14. Is provided.

  The image acquisition unit 2 is a high-energy tomographic image HD constituting a three-dimensional image represented by three-dimensional volume data obtained by performing dual energy imaging in an X-ray tomography apparatus (X-ray CT apparatus) 30. And a low-energy tomographic image LD, each having a communication interface function for acquiring via a LAN. The high energy tomographic image HD and the low energy tomographic image LD are transmitted from the X-ray tomography apparatus 30 via the LAN. In the present embodiment, it is assumed that a contrast medium is administered to a subject and an angiographic tomographic image obtained by contrasting blood vessels is acquired.

  The storage unit 4 is a large-capacity storage device such as a hard disk, and stores image data of a high energy tomographic image HD and a low energy tomographic image LD. Here, in the following description, the high energy tomographic image HD and the low energy tomographic image LD may be collectively referred to as dual energy tomographic images HD and LD. The storage unit 4 stores a plurality of dual energy tomographic images HD and LD with different subjects (that is, with different patients) or with the same subject and with different imaging times.

  FIG. 2 is a schematic block diagram showing the configuration of the X-ray tomography apparatus 30. The X-ray tomography apparatus 30 includes a gantry 32 and a bed 34 for inserting the subject H into the imaging region of the gantry 32. The bed 34 moves in the Z direction (the direction perpendicular to the paper surface), which is the body axis direction of the subject H. The gantry 32 has a rotating ring 36, and an X-ray tube 38 that irradiates the rotating ring 36 with cone-beam shaped X-rays, and an X-ray detector 40 that is disposed facing the X-ray tube 38 are attached. ing. The X-ray tube 38 is configured to emit X-rays having a high energy spectrum and X-rays having a low energy spectrum in accordance with an applied voltage. The X-ray detector 40 detects X-rays that have passed through the subject H.

  The X-ray detector 40 includes a scintillator and a photodiode, records a projection image of the subject H by irradiation of X-rays transmitted through the subject H, and outputs projection data representing the projection image.

  The X-ray tomography apparatus 30 includes a high voltage low voltage generator 42 and a scan controller 44. The high voltage / low voltage generator 42 periodically generates a high voltage and a low voltage (for example, 140 kV and 80 kV), and supplies the X-ray tube 38 with the high voltage and the low voltage. The tube voltage is not limited to 140 kV and 80 kV, and any combination of voltages can be used.

  The scan controller 44 executes a scan pattern such as an axial scan or a helical scan. The scan controller 44 rotates the rotation ring 36 by a rotation mechanism (not shown) in synchronization with the high-voltage / low-voltage generator 42 to periodically collect high-energy and low-energy projection data from the X-ray detector 40. Control related to dual energy imaging.

  The X-ray tomography apparatus 30 includes an image reconstruction unit 46 and an output unit 48. The image reconstruction unit 46 reconstructs an image based on each of high energy projection data and low energy projection data acquired by dual energy imaging, and generates a high energy tomographic image HD and a low energy tomographic image LD. To do. Here, the high energy tomographic image HD and the low energy tomographic image LD constitute three-dimensional volume data in which two-dimensional tomographic image data obtained in order along the direction perpendicular to the tomographic plane of the subject H is laminated. It has become.

  The output unit 48 has a function of a communication interface that transmits image data (three-dimensional volume data) of the high energy tomographic image HD and the low energy tomographic image LD to the tomographic image display device 1 via the LAN. Note that incidental information defined by the DICOM (Digital Imaging and Communications in Medicine) standard is added to the image data of the high energy tomographic image HD and the low energy tomographic image LD. The incidental information includes, for example, an image ID for identifying image data, a patient ID for identifying a subject, an examination ID for identifying an examination, a unique ID (UID) assigned to each image, and the image generated Examination date, examination time, type of modality used in the examination to obtain the image, patient information such as patient name, age, gender, examination site (imaging site), imaging condition (contrast agent used / not used) And tube voltage, radiation dose, etc.) information such as a series number or collection number when a plurality of images are acquired in one examination can be included.

  Here, dual energy imaging is performed, for example, by alternately switching the tube voltage of the X-ray tube 38 to 140 kV and 80 kV. The tube voltage is switched every view, every several views, or every scan.

  One scan is performed by full scan or half scan. The full scan is performed by rotating the X-ray tube 38 and the X-ray detector 40 by 360 degrees. The half scan is performed by rotating the X-ray tube 38 and the X-ray detector 40 by 180 + γ degrees. Note that γ is the opening angle of the X-rays emitted from the X-ray tube 38 in the xy plane. Furthermore, 360 degrees or 180 degrees may be divided by an integer value as a segment scan unit.

  Instead of switching the tube voltage of the X-ray tube 38, two systems of the X-ray tube 38 and the X-ray detector 40 are provided, the tube voltage of one system is 80 kV, and the tube voltage of the other system is 140 kV. Dual energy imaging may be performed by simultaneous X-ray irradiation. In this case, the X-ray irradiation direction is varied, for example, by 90 degrees between the two systems.

  By dual energy imaging, two types of projection data corresponding to two types of X-rays having different energies can be obtained. One of the two types of projection data is data acquired by X-rays having a maximum energy of 80 keV, and the other is data acquired by X-rays having a maximum energy of 140 keV.

  Two types of tomographic images can be obtained by reconstructing the projection data. Of the two types of tomographic images, the pixel value in one tomographic image is a pixel value (CT value) under an X-ray with a maximum energy of 80 keV, and the pixel value in the other tomographic image has a maximum energy of 140 keV. This is the pixel value under the X-ray. In the present embodiment, the former is referred to as a low energy tomographic image LD, and the latter is referred to as a high energy tomographic image HD. The high energy tomographic image HD and the low energy tomographic image LD are collectively referred to as dual energy tomographic images HD and LD.

  Returning to FIG. 1, the first image generation unit 6 removes the bones included in the high energy tomographic image HD and the low energy tomographic image LD based on the high energy tomographic image HD and the low energy tomographic image LD. The bone removal image G1 is generated. Hereinafter, the generation of the first bone removal image in the first image generation unit 6 will be described. First, the first image generation unit 6 classifies the pixels of the high energy tomographic image HD and the low energy tomographic image LD. The classification of the pixels is performed based on the characteristic value of the combination of the pixel values of the high energy tomographic image HD and the low energy tomographic image LD.

  As the characteristic value of the combination of pixel values, for example, the ratio of the pixel value of the low energy tomographic image LD (hereinafter referred to as low energy pixel value) and the pixel value of the high energy tomographic image HD (hereinafter referred to as high energy pixel value) is used. Use. Hereinafter, the ratio between the low energy pixel value and the high energy pixel value is simply referred to as a pixel value ratio. Also, the pixel value ratio is represented by LD / HD.

  The pixel value ratio LD / HD is usually in the range of about 2.00 to 1.55 for iodine which is the main component of the contrast agent, and about 1.55 to 1.35 for calcium which is the main component of the bone. Values range, soft tissue values in the range of about 1.35 to 0.95, fat values in the range of about 0.95 to 0.80. The classification of the pixels is performed using such characteristics of the pixel value ratio LD / HD. That is, a pixel having a pixel value ratio LD / HD in the range of 2.00 to 1.55 is classified as iodine, a pixel in the range of 1.55 to 1.35 is classified as calcium, and 1.35 to 0 Pixels in the range of .95 are classified as soft tissue, and pixels in the range of 0.95 to 0.80 are classified as fat.

  Here, when the histogram of the pixel value ratio LD / HD is obtained over all the pixels of the dual energy tomographic images HD and LD, a histogram as shown in FIG. 3 is obtained. As shown in FIG. 3, the histogram has a plurality of peaks. The plurality of peaks correspond to a plurality of substances in the subject, such as iodine, calcium, soft tissue, and fat, respectively.

  On the horizontal axis, the iodine peak is in the ab range, the calcium peak is in the bc range, the soft tissue peak is in the cd range, and the fat peak is in the de range. Is in range. The values of a, b, c, d, and e are about 2.00, 1.55, 1.35, 0.95, and 0.80, respectively. Fluctuates depending on.

  For this reason, the values of a, b, c, d, and e obtained from the histograms of the pixels of the high energy tomographic image HD and the low energy tomographic image LD are values in accordance with the actual effective mass number of the substance. Therefore, the pixels can be classified into iodine, calcium, soft tissue, and fat by using the values of a, b, c, d, and e as pixel classification criteria.

  Instead of the histogram, a two-dimensional distribution of pixel value combinations may be obtained. A two-dimensional distribution of combinations of pixel values is determined in a two-dimensional space having two coordinate axes corresponding to low energy pixel values and high energy pixel values.

  FIG. 4 is a diagram showing a two-dimensional distribution of combinations of pixel values. As shown in FIG. 4, a two-dimensional distribution is obtained by arranging a combination of pixel values (HD, LD) in a two-dimensional space with a high energy pixel value HD as a horizontal axis and a low energy pixel value LD as a vertical axis. It is done. Hereinafter, the distribution of combinations of pixel values is simply referred to as pixel distribution.

  As shown in FIG. 4, the distribution of iodine pixels forms group I, the distribution of calcium pixels forms group C, the distribution of soft tissue pixels forms group S, and the distribution of fat pixels is the group. F is formed. Pixel classification can be performed based on such a group. That is, the pixels belonging to the group I are classified as iodine, the pixels belonging to the group C are classified as calcium, the pixels belonging to the group S are classified as soft tissue, and the pixels belonging to the group F are classified as fat. The group I exists between the straight lines a and b, the group C exists between the straight lines b and c, the group S exists between the straight lines c and d, and the group F exists between the straight lines d and e. Exists. The straight lines a, b, c, d, and e form a group boundary.

  The inclinations of these boundary lines a, b, c, d, and e are, for example, about 2.00, 1.55, 1.35, 0.95, and 0.80, respectively. For this reason, the pixel can be classified into iodine, calcium, soft tissue, and fat using the boundary of the two-dimensional distribution of the combination of pixel values (HD, LD).

  Then, the first image generation unit 6 gives a label corresponding to the classification to the classified pixels. Then, in the high energy tomographic image HD or the low energy tomographic image LD, the opacity of the pixel to which the calcium label is assigned is set to 0 (that is, transparent), whereby the first bone-removed image G1 from which the bone portion has been removed. Can be generated.

  Note that the first bone removal image G1 may be generated by removing the bone portion by weighting and subtracting the high energy tomographic image HD from the low energy tomographic image LD. In this case, as the weight, the ratio of the pixel values of calcium in the low energy tomographic image LD and the high energy tomographic image HD may be used. As a result, as shown in FIG. 5, a bone part is removed, and a first bone removal image G1 from which an angiographic part is extracted is generated.

  The second image generation unit 8 recognizes a bone part in the high energy tomographic image HD, and generates a second bone removal image G2 in which the bone part is removed from the high energy tomographic image HD based on the recognition result. For example, the technique described in Patent Document 2 is used to remove the bone part in the second image generation unit 8. Here, the angiographic part on the tomographic image is often uniform and has a high image density, but since the cancellous bone exists in the center of the bone, the bone part on the tomographic image is not uniform. It is common to have an image density.

  For this reason, the second image generation unit 8 uses a uniform filter that extracts a region having a uniform density in the high energy tomographic image HD, and a region having a uniform image density in the high energy tomographic image HD is used. Explore. In the present embodiment, the uniform filter describes density conditions such as the maximum density value, minimum density value, dynamic range (density range), density gradient between adjacent areas, and the like in the area. The image generation unit 8 searches for a region in the high-energy tomographic image HD that satisfies the density condition indicated by the uniform filter. As a result, as shown in FIG. 6, the bone part, which is a tissue having a non-uniform density, is removed from the high-energy tomographic image HD, and the angiographic part, which is a tissue having a uniform density, is extracted. A removed image G2 is generated.

  Here, the first bone removal image G1 and the second bone removal image G2 are compared. Both the first bone removal image G1 and the second bone removal image G2 are images in which the bone portion is removed and only the angiographic portion is extracted, but the presence or absence of calcification of the blood vessel wall is different. That is, since the calcified portion contains calcium similar to that of bone, the first image generation unit 6 removes the bone portion and the calcified portion by the processing performed by the first image generation unit 6 and angiography. It contains only the part. On the other hand, since the calcified portion has a uniform density similarly to the angiographic portion, only the bone portion is removed from the second bone removal image G2, and the angiographic portion and the calcified portion (arrow portions in FIG. 6). Is included. For this reason, the presence or absence of calcification of the blood vessel wall can be distinguished by comparing the first and second bone removal images G1 and G2.

  The display control unit 10 displays the first and second bone removal images G1 and G2 on the display unit 12 in a switchable manner. At this time, using a method such as a maximum value projection method (MIP method), MIP display or the like, volume rendering (VR) display, surface rendering (SR) display of an angiographic portion (ie, pseudo three-dimensional) is performed. Display).

  The display unit 12 includes a known display device such as a liquid crystal display.

  The input unit 14 includes a known input device such as a keyboard and a mouse.

  Next, processing performed in the first embodiment will be described. FIG. 7 is a flowchart showing processing performed in the first embodiment. Note that the dual energy tomographic images HD and LD are acquired by the X-ray tomography apparatus 30 and stored in the storage unit 4.

  When the user inputs an instruction to start processing to the tomographic image display device 1 using the input unit 16 (Yes in step ST1), the first image generation unit 6 generates the first bone removal image G1 (step ST2). ), The second image generation unit 8 generates the second bone removal image G2 (step ST3). And the display control part 10 displays the 1st and 2nd bone removal images G1 and G2 on the display part 12 so that a comparison is possible (step ST4), and complete | finishes a process.

  FIG. 8 is a diagram showing a display screen of the first and second bone removal images G1 and G2 in the first embodiment. As shown in FIG. 8, the display screen 60 displays an image display area 62 for displaying the first and second bone removal images G1 and G2 and blood vessel calcification on / off buttons 64A and 64B. . On the display screen 60, when the user selects the vascular calcification on button 64A using the input unit 14, the second bone removal image G2 including the calcification portion is displayed in the image display area 62 (FIG. 8A )). On the other hand, when the user selects the vascular calcification off button 64B using the input unit 14, a first bone removal image G1 that does not include a calcified portion is displayed in the image display area 62 (FIG. 8B). Note that the first bone removal image G1 and the second bone removal image G2 may be displayed side by side.

  Thus, in the first embodiment, the first image generation unit 6 generates the first bone-removed image G1 including only the angiographic portion by removing the bone portion and the calcified portion, and the second The image generation unit 8 of FIG. 2 generates only a second bone removal image G2 including an angiographic portion and a calcification portion from which only the bone portion has been removed, and the display control unit 10 performs the first and second bone removal images G1. , G2 are displayed on the display unit 12 in a comparable manner. For this reason, by comparing the first and second bone removal images G1 and G2, the angiographic portion and the calcified portion can be separated. Therefore, it is possible to accurately diagnose blood vessels by observing the angiographic portion and the calcified portion.

  Next, a second embodiment of the present invention will be described. FIG. 9 is a schematic block diagram showing a configuration of a tomographic image display device according to the second embodiment of the present invention. In FIG. 9, the same components as those in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted. The tomographic image display device 1A according to the second embodiment is included in the high energy tomographic image HD and the low energy tomographic image LD by weighting and subtracting the first bone removed image G1 and the second bone removed image G2. The point provided with the 3rd image generation part 16 which produces | generates the calcification image G3 which extracted the calcification part differs from 1st Embodiment.

  As shown in FIG. 10, the third image generation unit 16 weights and subtracts the first bone removal image G1 from the second bone removal image G2, thereby including only calcification of the blood vessel wall. An image G3 is generated. The weighting factor w may be set so that the pixel values of the angiographic portion in the first bone removal image G1 and the angiographic portion in the second bone removal image G2 are the same.

  In the high-energy tomographic image HD or the low-energy tomographic image LD, the first bone extraction image in which the bone part is extracted by setting the opacity of the pixels to which the iodine, soft tissue, and fat labels are assigned to 0. Can be generated. In the first bone extraction image, a bone part and a calcified part are extracted. On the other hand, in the high energy tomographic image HD, a second bone extraction image in which a bone part is extracted can be generated by extracting a region having a non-uniform density using the method described in Patent Document 2. Here, only the bone part is extracted from the second bone extraction image, and the calcified part is not extracted. Therefore, the calcified image G3 including only the calcification of the blood vessel wall can be generated also by generating the first and second bone extraction images and weighting and subtracting these images.

  Next, processing performed in the second embodiment of the present invention will be described. FIG. 11 is a flowchart showing processing performed in the second embodiment of the present invention. When the user inputs an instruction to start processing to the tomographic image display apparatus 1 using the input unit 14 (Yes in step ST11), the first image generation unit 6 generates the first bone removal image G1 (step ST12). ), The second image generation unit 8 generates the second bone removal image G2 (step ST13). Further, the third image generation unit 16 generates a calcified image G3 (step ST14). And the display control part 10 displays the 1st and 2nd bone removal images G1 and G2 on the display part 12 so that a comparison is possible (step ST15), and complete | finishes a process.

  FIG. 12 is a diagram showing a display screen of the first and second bone removal images G1 and G2 in the second embodiment. As shown in FIG. 12, the display screen 70 displays an image display area 72 and a vascular calcification on / off button 74 for displaying the first and second bone removal images G1 and G2. On the display screen 70, when the user selects the blood vessel calcification on button 74 </ b> A using the input unit 14, the second bone removal image G <b> 2 including the calcification portion is displayed in the image display area 72. Here, in the second embodiment, the point that the display control unit 10 refers to the calcified image G3 and gives a color to the region corresponding to the calcified portion in the second bone removal image G2. This is different from the embodiment (FIG. 12A). In FIG. 12, the color is given by hatching. Further, instead of giving color, the calcified portion may be made visible by indicating the calcified portion with an arrow. On the other hand, when the user selects the vascular calcification off button 74B by using the input unit 14, the first bone removal image G1 that does not include the calcification portion is displayed in the image display area 72 (FIG. 12B).

  As described above, in the second embodiment, the calcified portion is displayed so as to be visible in the second bone removal image G2, so that the calcified portion can be more reliably recognized. The blood vessel diagnosis can be performed with higher accuracy by observing the contrasted portion and the calcified portion.

  In the second embodiment, the second bone removal image G2 and the first bone removal image G1 in which a color is added to the calcified portion may be displayed side by side. Further, the calcified image G3 may be superimposed and displayed on the first bone removal image G1.

  In the first and second embodiments, the second image generation unit 8 generates the second bone removal image G2 from the high energy tomographic image HD. Two bone removal images G2 may be generated. However, between the high energy tomographic image HD and the low energy tomographic image LD, the high energy tomographic image HD has a lower contrast and less noise. Therefore, when extracting an angiographic portion, the high energy tomographic image HD is used. preferable.

  On the other hand, the high energy tomographic image HD acquired by the dual energy imaging has low contrast but little noise. In contrast, the low energy tomographic image LD has a high contrast but a lot of noise. For this reason, the high energy tomographic image HD and the low energy tomographic image LD are weighted and added to generate a composite image having an image quality that makes it easy to recognize a desired tissue in the image. For this reason, the second image generation unit 8 generates a composite image by weighting and adding the high energy tomographic image HD and the low energy tomographic image LD with a composite ratio so that the angiographic part can be easily recognized. The bone part may be removed from the image to generate the second bone removal image G2.

DESCRIPTION OF SYMBOLS 1,1A Tomographic image display apparatus 2 Image acquisition part 4 Memory | storage part 6 1st image generation part 8 2nd image generation part 10 Display control part 12 Display part 14 Input part 30 X-ray tomographic imaging apparatus 50 Image information database

Claims (5)

Based on the first and second medical images acquired by performing dual energy imaging of the subject using two types of radiation having different energies, the bones included in the first and second medical images are First image generation means for generating a removed first bone removal image;
Recognizing a tissue included in at least one of the first and second medical images or a composite image generated from the first and second medical images, and based on the recognition result, the first And second image generation means for generating a second bone-removed image obtained by removing a bone part included in the second medical image or the composite image;
A medical image display apparatus comprising: display control means for displaying the first and second bone removal images in a comparable manner. A third image generating means for generating a calcified image obtained by extracting a calcified portion included in the first and second medical images;
The said display control means is a means to display the said calcification part so that visual recognition is possible in either of the said 1st and said 2nd bone removal images based on the said calcification image. The medical image display device according to 1.   3. The medical image display apparatus according to claim 1, wherein the display control means is means for displaying the first and second bone removal images in a pseudo three-dimensional manner. Based on the first and second medical images acquired by performing dual energy imaging of the subject using two types of radiation having different energies, the bones included in the first and second medical images are Generating a removed first bone removal image;
Recognizing a tissue included in at least one of the first and second medical images or a composite image generated from the first and second medical images, and based on the recognition result, the first And generating a second bone-removed image in which a bone part included in the second medical image or the composite image is removed;
And a step of displaying the first and second bone-removed images in a comparable manner. Included in the first and second medical images based on the first and second medical images acquired by dual energy imaging of the subject using two types of radiation having different energies in the computer Generating a first bone removal image with the bone removed;
Recognizing a tissue included in at least one of the first and second medical images or a composite image generated from the first and second medical images, and based on the recognition result, the first And a procedure for generating a second bone-removed image in which a bone portion included in the second medical image or the composite image is removed;
And a procedure for displaying the first and second bone removal images in a comparable manner.