JP7450467B2 - Medical image processing equipment, X-ray diagnostic equipment, and medical image processing programs - Google Patents

Description

Embodiments disclosed in this specification and the drawings relate to a medical image processing device, an X-ray diagnostic device, and a medical image processing program.

When performing catheter treatment, the user displays in real time an X-ray fluoroscopic image (hereinafter referred to as a "contrast image") based on the X-ray imaging of the subject after administration of a contrast agent by an X-ray diagnostic device, and displays the contrast image depicted in the contrast image. The procedure may be performed while checking the position of devices such as catheters, guide wires, and embolic coils.

In this case, a reference image may be presented to assist the user in understanding the positional relationship between the blood vessel and the device. For example, in the treatment of lower extremity CTO (Chronic Total Occlusion) using a bidirectional approach (also called the rendezvous technique), and in the evaluation of aneurysms after coil embolization, understanding the positional relationship between the blood vessel run and the device. It is important to.

As this type of reference image, a DSA (Digital Subtraction Angiography) image is often used. DSA images are obtained by, for example, photographing the same region of a subject in time series with an X-ray diagnostic device before and after administration of a contrast agent. Specifically, a plurality of difference images corresponding to each time phase obtained by subtracting the mask image from the contrast images of each time phase after contrast agent administration are used as DSA images.

However, in the DSA image, devices disappear due to differential processing. Therefore, when performing a procedure while referring to a DSA image, the user must imagine the position of the device, which is inconvenient.

Japanese Patent Application Publication No. 2015-150371

One of the problems to be solved by the embodiments disclosed in this specification and the drawings is to depict blood vessel running and a device in one image. However, the problems to be solved by the embodiments disclosed in this specification and the drawings are not limited to the above problems. Problems corresponding to the effects of each configuration shown in the embodiments described later can also be positioned as other problems.

A medical image processing apparatus according to an embodiment includes an X-ray image acquisition section and a reference image generation section. The X-ray image acquisition unit acquires an X-ray image in which the device and contrast blood vessels are depicted. The reference image generation unit generates a reference image having a first region representing an X-ray image and a second region representing a contrast blood vessel extracted from the X-ray image.

FIG. 1 is a block diagram illustrating a configuration example of a medical image processing apparatus according to a first embodiment. 2 is a flowchart illustrating an example of a schematic procedure when a processor of a processing circuit of a medical image processing apparatus executes processing for generating a reference image in which blood vessel running and a device are depicted in one image. (a) is an explanatory diagram showing an example of a mask image in a procedure using a bidirectional approach for lower extremity CTO treatment, (b) is an explanatory diagram showing an example of a contrast image, and (c) is an explanatory diagram showing an example of a DSA image. FIG. 3 is an explanatory diagram showing an example of a reference image generated based on a first area and a second area set by a first setting method. FIG. 7 is an explanatory diagram showing an example of a reference image generated based on a first area and a second area set by a second setting method. FIG. 7 is an explanatory diagram showing an example of a reference image generated based on the first region and the second region set by the third setting method. FIG. 5 is an explanatory diagram showing an example of a transition area set for the first area and the second area set by the first setting method shown in FIG. 4; (a) is an explanatory diagram showing an example of the relationship between the y coordinate and the coefficient α of equation (1) in the example shown in FIG. 7, and (b) is an explanatory diagram showing another example. FIG. 6 is a diagram for explaining a case where the entire area of a reference image 60 is treated as a transition area. FIG. 10 is an explanatory diagram showing the relationship between the y coordinate and the coefficient α of equation (1) in the example shown in FIG. 9; FIG. 2 is a block diagram illustrating a configuration example of an X-ray diagnostic apparatus including a medical image processing apparatus according to a second embodiment.

Hereinafter, embodiments of a medical image processing device, an X-ray diagnostic device, and a medical image processing program will be described in detail with reference to the drawings.

(Summary of configuration and operation)
FIG. 1 is a block diagram showing an example of the configuration of a medical image processing apparatus 10 according to the first embodiment. The medical image processing apparatus 10 is configured by, for example, a general personal computer or workstation, and has an input interface 11, a display 12, a storage circuit 13, a network connection circuit 14, and a processing circuit 15.

The input interface 11 is configured with a general input device such as a trackball, a switch button, a mouse, a keyboard, and a numeric keypad, and outputs an operation input signal corresponding to a user's operation to the processing circuit 15. The display 12 is configured by a general display output device such as a liquid crystal display or an OLED (Organic Light Emitting Diode) display.

The storage circuit 13 has a configuration including a recording medium readable by a processor, such as a RAM (Random Access Memory), a semiconductor memory element such as a flash memory, a hard disk, an optical disk, etc., and stores programs used by the processing circuit 15. , parameter data, and other data. Note that part or all of the program and data in the recording medium of the storage circuit 13 may be downloaded by communication via the network 100, or may be provided to the storage circuit 13 via a portable storage medium such as an optical disk. You can.

The network connection circuit 14 implements various information communication protocols depending on the form of the network 100. The network connection circuit 14 connects to other electrical devices via the network 100 according to these various protocols. The network 100 refers to a general information communication network using telecommunications technology, and includes wireless/wired LAN such as a hospital backbone LAN (Local Area Network), Internet network, telephone communication line network, optical fiber communication network, and cable communication. networks and satellite communications networks.

The medical image processing apparatus 10 is connected to an X-ray diagnostic apparatus 101 such as an X-ray angiography apparatus or an X-ray TV apparatus, an image server 102, and the like via a network 100 so as to be able to exchange data with each other.

The image server 102 is a server for long-term storage of images provided in, for example, a PACS (Picture Archiving and Communication System), and is a server for long-term storage of images generated by, for example, the X-ray diagnostic apparatus 101 connected via the network 100. It stores medical images such as X-ray fluoroscopic images and DSA images.

Although FIG. 1 shows an example in which the medical image processing apparatus 10 and the X-ray diagnostic apparatus 101 are connected via the network 100, they may be directly connected without going through the network 100. Standards used for direct connection include the ATA (Advanced Technology Attachment) standard, SCSI (Small Computer System Interface) standard, LTO (Linear Tape-Open) standard, as well as wired standards such as the USB (Universal Serial Bus) standard and the IEEE1394 standard. It may be a communication standard or a wireless communication standard such as infrared communication.

When acquiring and utilizing contrast images generated by the X-ray diagnostic apparatus 101 in real time, the medical image processing apparatus 10 is installed, for example, in an examination room where the imaging system of the X-ray diagnostic apparatus 101 is installed.

The processing circuit 15 realizes a function of controlling the medical image processing apparatus 10 in an integrated manner. Further, the processing circuit 15 is a processor that reads and executes a medical image processing program stored in the storage circuit 13 to execute processing for depicting blood vessel running and a device in one image.

Specifically, as shown in FIG. 1, the processor of the processing circuit 15 implements an X-ray image acquisition function 21, a position acquisition function 22, a DSA image generation function 23, and a reference image generation function 24. Each of these functions is stored in the storage circuit 13 in the form of a program.

The X-ray image acquisition function 21 acquires an X-ray image (contrast image) in which the device and contrast-enhanced blood vessels are depicted. The contrast image may be acquired in real time from a live image generated by the X-ray diagnostic apparatus 101, or may be acquired in post-processing from the X-ray diagnostic apparatus 101 or the image server 102 after the examination by the X-ray diagnostic apparatus 101 is completed. good. The X-ray image acquisition function 21 is an example of an X-ray image acquisition section.

The position acquisition function 22 acquires the position of at least a point of interest on the device. If the device is a catheter, the point of interest may be, for example, the tip of the catheter, and if the device is an embolic coil, the point of interest may be, for example, the spherical surface or center of a virtual circumscribed sphere of the embolic coil. The position acquisition function 22 is an example of a position acquisition unit.

In addition, if a radiopaque marker made of a radiopaque material such as tungsten is provided at the tip of the catheter, the position acquisition function 22 detects the marker from the contrast image to determine the location of the catheter. The position of the tip can be obtained. Furthermore, if markers are provided at different predetermined distances from the tip of the catheter (for example, 10, 20, and 30 cm from the tip), the position acquisition function 22 detects these multiple markers from the contrast image. Information about the catheter tip position and the catheter running direction can be acquired. Further, when the main body of the catheter includes a radiopaque material, the position acquisition function 22 can detect and acquire the entire position of the catheter included in the contrast image.

The DSA image generation function 23 generates a plurality of contrast images by subtracting each contrast image of a plurality of time-series contrast images of the subject after contrast agent administration and a mask image based on the image of the subject before contrast agent administration. Generate a DSA image of A DSA image is an example of an image showing contrast-enhanced blood vessels. The DSA image generation function 23 is an example of a DSA image generation section.

Note that the DSA image generation function 23 performs alignment conversion of the mask image based on the amount of positional deviation between each contrast image and the mask image, for example, using each contrast image as a reference, that is, aligning the mask image with each contrast image. , it is preferable to generate a plurality of DSA images by subtracting each contrast image and the mask image.

In addition, image alignment transformations include methods using affine transformation, pattern matching using edge detection, pattern matching using feature amounts, methods using correlation between images, and methods using anatomical landmarks. Various methods are known in the past, such as methods using , and it is possible to use any of these methods. Further, the alignment transformation may be a linear transformation or a nonlinear transformation. In this case, a DSA image is generated by linearly and/or non-linearly aligning the contrast image and the mask image and then calculating the difference.

Further, the DSA image 33 may be generated from the contrast image using a learned model constructed by machine learning. In this case, the DSA image generation function 23 generates a contrast image obtained by the X-ray image acquisition function 21 for a trained model that outputs a DSA image showing contrast-enhanced blood vessels depicted in the contrast image based on the contrast image. By inputting 32, a DSA image 33 is generated.

As machine learning, deep learning using a multilayer neural network such as a CNN (convolutional neural network) or a convolutional deep belief network (CDBN) can be used. In this case, the learned model can be constructed by performing deep learning using a large number of training data sets in which contrast images are training data and DSA images corresponding to the contrast images are training data.

The reference image generation function 24 generates a reference image that has a first region showing an X-ray image (contrast image) and a second region showing a contrast blood vessel extracted from the X-ray image. For example, the reference image generation function 24 assigns a portion corresponding to the first region of the contrast image to the first region of the reference image, and assigns a portion corresponding to the first region of the DSA image to the second region of the reference image. A reference image is generated by assigning a portion corresponding to . In this case, the reference image can be said to be an image that partially uses the DSA image (partial DSA image). The reference image generation function 24 is an example of a reference image generation section.

FIG. 2 shows an example of a schematic procedure when the processor of the processing circuit 15 of the medical image processing apparatus 10 executes processing for generating a reference image in which blood vessel running and a device are depicted in one image. It is a flowchart. In FIG. 2, the symbols with numbers added to S indicate each step of the flowchart.

First, in step S1, the X-ray image acquisition function 21 acquires a contrast image in which the device and contrast blood vessels are depicted. If contrast images can be acquired from the X-ray diagnostic apparatus 101 in real time, the X-ray image acquisition function 21 sequentially acquires contrast images in real time at a predetermined frame rate.

Next, in step S2, the position acquisition function 22 acquires the position of at least the point of interest on the device. If a contrast image can be acquired from the X-ray diagnostic apparatus 101 in real time, the position acquisition function 22 may acquire the position of at least the target point of the device and update the position every time a contrast image is acquired. .

Next, in step S3, the DSA image generation function 23 generates a plurality of DSA images by subtracting each of the plurality of contrast images and the mask image. If a contrast image can be acquired from the X-ray diagnostic apparatus 101 in real time, the DSA image generation function 23 may generate a DSA image every time a contrast image is acquired.

Next, in step S4, the reference image generation function 24 sets a first area and a second area based on the position of at least the point of interest on the device. If a contrast image can be acquired from the X-ray diagnostic apparatus 101 in real time, the reference image generation function 24 generates a first It is preferable to set an area and a second area.

Note that the processes in steps S2, S3, and S4 may be performed in a different order, or may be performed in parallel.

Next, in step S5, the reference image generation function 24 generates a reference image having a first region showing a contrast image and a second region showing a contrast blood vessel extracted from the X-ray image.

By the above procedure, it is possible to generate a reference image in which the blood vessel running and the device are depicted in one image.

The device and contrast blood vessels are depicted in the contrast image. However, since background images such as bones are also depicted in the contrast image, the contrast-enhanced blood vessels depicted in the contrast image are unclear. On the other hand, although contrast-enhanced blood vessels are clearly depicted in the DSA image, the device is not depicted.

Therefore, the medical image processing apparatus 10 according to the present embodiment generates a reference image having a first region showing a contrast image and a second region showing a contrast blood vessel extracted from the X-ray image.

(Specific example of operation)
Next, a method for generating a reference image to be presented to a user during a procedure using a bidirectional approach for lower extremity CTO treatment will be specifically described.

In a bidirectional approach, a device is inserted into a blood flow obstruction (CTO) from two directions, one upstream and one downstream. For example, with these two devices, a procedure is performed in which a guidewire is advanced from the upstream side of the bloodstream and a microcatheter is advanced from the downstream side of the bloodstream, and the guidewire is manipulated and inserted into the microcatheter on the contralateral side. . Note that a microcatheter may be placed on the upstream side of the blood flow, and a guide wire may be placed on the downstream side of the blood flow.

When inserting the guidewire into the contralateral microcatheter, it is important to understand the positional relationship between the blood vessel direction and the microcatheter.

FIG. 3(a) is an explanatory diagram showing an example of a mask image 31 in a procedure using a bidirectional approach for lower extremity CTO treatment, (b) is an explanatory diagram showing an example of a contrast image 32, and (c) is an explanatory diagram showing an example of a contrast image 32. 3 is an explanatory diagram showing an example of an image 33. FIG.

The mask image (background image) 31 may be an average image of a plurality of X-ray fluoroscopic images before contrast agent administration, or may be one X-ray fluoroscopic image taken at a predetermined moment before contrast agent administration.

Since the procedure is being performed using a bidirectional approach, the mask image 31 depicts the guide wire 51 inserted from the blood flow upstream side of the blood vessel 41 of the lower limb 40 toward the blood flow obstruction 42, and also depicts the guide wire 51 inserted toward the blood flow obstruction 42. A microcatheter 52 inserted into the blood vessel 41 from the downstream side of the blood flow toward the blood flow obstruction 42 in the opposite direction to that of the microcatheter 51 is depicted (see FIG. 3(a)). The mask image 31 also depicts images of bones, etc., which are not shown.

In the contrast image (contrast image) 32, a contrasted blood vessel (contrast blood vessel) 41a of the blood vessel 41 and a microcatheter 52 are depicted (see FIG. 3(b)). Therefore, by referring to the contrast image 32, the user can easily grasp the position of the microcatheter 52.

Note that in the contrast image 32, a blood vessel (non-contrast blood vessel) 41b that is not contrasted because the contrast agent does not reach it due to a blood flow obstruction is extremely unclear and difficult to distinguish. Furthermore, the background such as bones is also depicted in the contrast image 32, similar to the mask image 31. For this reason, the contrast-enhanced blood vessels 41a drawn in the contrast image 32 also lack distinguishability, although not as well as the non-contrast blood vessels 41b.

The DSA image (difference image) 33 is an image generated by subtracting the contrast image 32 and the mask image 31 by the DSA image generation function 23. Therefore, the contrast-enhanced blood vessel 41a is depicted very clearly in the DSA image 33 (see FIG. 3(c)). Therefore, by referring to the DSA image 33, the user can easily understand the course of blood vessels. However, the microcatheter 52 is not depicted in the DSA image 33.

Therefore, the medical image processing apparatus 10 according to the present embodiment has a first region to which the contrast image 32 is assigned, in which the microcatheter 52 is depicted and its position can be easily grasped, and the contrast blood vessel 41a is depicted very clearly. By generating a reference image having a second region to which the DSA image 33 is assigned, which makes it easy to understand the blood vessel running, it is possible to assist in understanding the positional relationship between the microcatheter 52 and the blood vessel running.

(How to set the first area and second area)
Next, a method for setting the first region and the second region during a procedure using a bidirectional approach for lower extremity CTO treatment will be described. Here, three examples of methods for setting the first area and the second area will be described.

FIG. 4 is an explanatory diagram showing an example of the reference image 60 generated based on the first area 61 and the second area 62 set by the first setting method.

The first setting method is to set a boundary line 71 that divides the reference image 60 into two based on the position of the tip 52t of the microcatheter 52.

While observing the lower limbs, the image is generated so that the head is located at the top of the image and the feet are located at the bottom of the image. Therefore, it is estimated that the microcatheter 52 inserted into the blood vessel 41 from the downstream side of the blood flow is located in the lower region of the image when viewed from the tip 52t. Therefore, when the position acquisition function 22 acquires the position of the tip 52t of the microcatheter 52, the reference image generation function 24 sets a boundary line 71 that passes through the tip 52t and crosses the reference image 60 from side to side. The lower side is a first area 61 to which a contrast image 32 is assigned where the microcatheter 52 is depicted and its position can be easily grasped, and the upper side of the boundary line 71 is a first area 61 to which a DSA image 33 is assigned where the blood vessel running can be easily grasped. It is preferable to set the area 62 of 2 (see FIG. 4).

In addition, when the position acquisition function 22 acquires information on the running direction of the microcatheter 52 (downward from the tip 52t in the example shown in FIG. 4) in addition to the position of the tip 52t of the microcatheter 52, the reference image generation function 24, it is preferable to set the boundary line 71, the first region 61, and the second region 62 so that the microcatheter 52 belongs to the first region 61. In this case, the boundary line 71 is not limited to crossing the reference image 60 left and right, but may cross the reference image 60 vertically or diagonally depending on the running direction of the microcatheter 52. . Further, the boundary line 71 is not limited to a straight line, but may be a curved line.

The first setting method is applicable even when the contrast image 32 generated by the X-ray diagnostic apparatus 101 is acquired and used in real time. In this case, the reference image generation function 24 sets the boundary line 71 and sets the first region 61 and the second region 62 every time the contrast image 32 is acquired, and creates a contrast image in the first region 61. 32, a reference image 60 is generated by allocating the DSA image 33 to the second area 62.

FIG. 5 is an explanatory diagram showing an example of the reference image 60 generated based on the first area 61 and the second area 62 set by the second setting method.

The second setting method is to set a boundary line 71 that divides the reference image 60 into two based on the overall position of the microcatheter 52.

When the position acquisition function 22 acquires the entire position of the microcatheter 52, the reference image generation function 24 sets the boundary line 71 to include the entire microcatheter 52, thereby separating the first area 61 and the second area. 2 area 62 is set. At this time, the boundary line 71 includes a straight line (see FIG. 5) or a curved line passing through the tip 52t, and a straight line (see FIG. 5) or a curved line extending along the length direction of the microcatheter 52 from both ends of this straight line or curved line. It is composed of A portion of the boundary line 71 extending along the length direction of the microcatheter 52 may be set at a position separated from the microcatheter 52 by a predetermined distance.

The reference image 60 generated by the second setting method can make the first region 61 where the background image is drawn narrower than the reference image 60 generated by the first setting method. Therefore, it becomes easier for the user to grasp the positional relationship between the microcatheter 52 and the blood vessel.

Similar to the first setting method, the second setting method is applicable even when the contrast image 32 generated by the X-ray diagnostic apparatus 101 is acquired and used in real time.

FIG. 6 is an explanatory diagram showing an example of the reference image 60 generated based on the first area 61 and the second area 62 set by the third setting method.

A third setting method is a method of setting the boundary line 71 based on the position of the tip 52t of the microcatheter 52 and the positions of all the contrast blood vessels 41a included in the reference image 60.

The degree to which the blood vessel 41 is stained with the contrast medium differs depending on the time phase, depending on the time that has passed since the contrast medium was administered. Therefore, in order to specify the positions of all contrast-enhanced blood vessels 41a included in the reference image 60, it is necessary to aggregate information from a plurality of contrast images 32. It is preferable to aggregate 32 pieces of information. Therefore, the third setting method is suitable for post-processing and is not suitable for real-time processing.

When the position of the contrast blood vessel 41a on the left side of FIG. A boundary line 71 is set by a straight line or a curved line extending in the vertical direction (see FIG. 6). A straight line extending in the vertical direction between the specified contrast blood vessel 41a and the microcatheter 52 may be set at a position corresponding to the distance between the specified contrast blood vessel 41a and the microcatheter 52. The distance between the specified contrast blood vessel 41a and the microcatheter 52 may be represented by the distance between the specified contrast blood vessel 41a and the tip 52t of the microcatheter 52 along the left-right direction. The position corresponding to the specified distance between the contrast blood vessel 41a and the microcatheter 52 can be a position away from the microcatheter 52 by, for example, 1/2, 1/3, or 1/4 of the distance.

The reference image 60 generated by the third setting method can make the first region 61 in which the background image is drawn narrower than the reference image 60 generated by the first setting method. Therefore, although it is inferior to the second setting method, it is easier for the user to grasp the positional relationship between the microcatheter 52 and the blood vessel running than the first setting method.

In the above description, an example is shown in which the original image of the contrast image 32 is assigned to the first region 61, but a high frequency component image of the contrast image 32 may be assigned to the first region 61. The reference image generation function 24 can generate a high frequency component image of the first region 61 by, for example, taking a difference between the contrast image 32 and a low frequency image of the contrast image 32.

The high-frequency component image is an image in which contour components such as edges of devices and bones remain. Therefore, the image looks closer to the DSA image 33 than the original image of the contrast image 32, and the discomfort between the two images in the reference image 60 becomes less pronounced. Therefore, when assigning the high frequency component image of the contrast image 32 to the first region 61, the reference image 60 as a whole becomes an image that is easy for the user to see.

Further, in this case, by generating a high frequency component image to be assigned to the first region 61 in the same manner as the DSA image 33, the user's discomfort can be further reduced. For example, if the DSA image 33 is generated by determining the natural logarithm of the X-ray intensities of the contrast image 32 and the mask image 31 and then taking the difference between them, the high frequency component image will also be generated using the contrast image 32 and its lower It is preferable that the image be generated by calculating the natural logarithm of the frequency component image and then calculating the difference. Furthermore, when the DSA image 33 is generated by directly subtracting the contrast image 32 and the mask image 31, the high frequency component image is also generated by directly subtracting the contrast image 32 and its low frequency component image. Good.

In this way, by generating a high frequency component image to be assigned to the first area 61 in the same manner as the DSA image 33, the gradation of the high frequency component image of the first area 61 and the DSA image 33 of the second area 62 can be adjusted. , brightness, etc. are similar, so that the reference image 60 as a whole becomes an image that is easier for the user to see.

Furthermore, although the method for generating the reference image 60 to be presented to the user during the procedure using the bidirectional approach of lower extremity CTO treatment has been described up to this point, the method for generating the reference image 60 can be applied to various other treatment techniques and examination techniques. It is possible. For example, the present generation method can also be applied to post-coil embolization evaluation of cerebral aneurysms and other aneurysms. In this case, the position acquisition function 22 preferably acquires the position of the spherical surface or center of the virtual circumscribed sphere of the embolic coil, as described above. The reference image generation function 24 depicts the embolic coil in the first region 61 and assigns the DSA image 33 to the second region 62 so that the contrast blood vessel 41a is depicted based on the position of the embolic coil. The first area 61 and the second area 62 may be set. For example, first region 61 may be spherical containing the embolic coil.

(transition area)
Next, the transition area 63 between the first area 61 and the second area 62 will be explained.

The reference image generation function 24 may set a transition area 63 between the first area 61 and the second area 62 in the reference image 60. In this case, the reference image generation function 24 generates an attenuation image in the transition region 63 such that the closer to the second region 62 the more strongly the contrast image 32 is attenuated by the components of the mask image 31.

The transition area 63 can be set using any of the first to third setting methods shown in FIGS. 4-6. The transition area 63 between the first area 61 and the second area 62 set by the first setting method shown in FIG. 4 will be described below.

FIG. 7 is an explanatory diagram showing an example of the transition region 63 set for the first region 61 and the second region 62 set by the first setting method shown in FIG. In the following description, as shown in FIG. 7, x and y coordinates are used in which the horizontal direction of the image is the x axis, the vertical direction is the y axis, and the lower left corner is the origin.

In FIG. 7, the region transition depends only on the y-coordinate and not on the x-coordinate. An example is shown below. Further, the y coordinate of the upper end of the reference image 60 is assumed to be E.

The transition region 63 may have a lower end L as a boundary line 71 and an upper end H as a position a predetermined width from the lower end L in the direction of the second region 62 (see FIG. 7), or the boundary line 71 may be the upper end H. , may be set to straddle the boundary line 71.

If the pixel value of the contrast image 32 is Contrast(x,y), the pixel value of the mask image 31 is Mask(x,y), and 0<β<1, the pixel value (x,y) in the reference image 60 is It is generalized as shown in the following equation (1).

The transition area 63 is an area provided to smoothly connect the first area 61 and the second area 62. The relationship between the DSA image 33 and the contrast image 32 is based on whether or not they are images obtained by taking a difference from the mask image 31. Therefore, the attenuation image assigned to the transition region 63 is preferably generated so that the closer the position is to the second region 62, the more strongly the contrast image 32 is attenuated by the components of the mask image 31. Therefore, β in equation (1) is preferably set so that the closer to the second region 62, the closer to 1.

FIG. 8(a) is an explanatory diagram showing an example of the relationship between the y coordinate and the coefficient α of equation (1) in the example shown in FIG. 7, and FIG. 8(b) is an explanatory diagram showing another example.

As shown in FIG. 8A, β in equation (1) may be set linearly so that the closer to the second region 62, the closer to 1. Further, as shown in FIG. 8(b), β is set in a curved manner so as to reduce the sense of discomfort at the boundary between the first region 61 and the transition region 63 and the boundary between the transition region 63 and the second region 62. may be done. In the example shown in FIG. 8(b), the value of β may be stored in the storage circuit 13 as a look-up table or as a polynomial approximation expression.

Similarly, when assigning the high frequency component image of the contrast image 32 to the first region 61, if the pixel value of the low frequency component image is LowFreq(x,y), the pixel value (x,y ) can be generalized as shown in the following equation (2).

By setting the transition area 63 and assigning to the transition area 63 an attenuated image that is generated so that the contrast image 32 is more strongly attenuated by the components of the mask image 31 at positions closer to the second area 62, the first area 61 and the images of the second area 62 can be connected in a gradation manner. Therefore, the sense of discomfort near the boundary line 71 can be significantly reduced, and the ease of viewing the reference image 60 as a whole can be improved.

Note that the transition region 63 is at least the boundary line closest to the tip 52t of the microcatheter 52 among the boundaries 71 (in the case of a straight line, it is a straight line passing through the point closest to the tip; in the case of a curve, it is within a predetermined distance from the tip). It is best to set this to the border area, etc.).

FIG. 9 is a diagram for explaining a case where the entire area of the reference image 60 is treated as the transition area 63. Further, FIG. 10 is an explanatory diagram showing the relationship between the y coordinate and the coefficient α of equation (1) in the example shown in FIG.

As shown in FIGS. 9 and 10, as a modification of the aspects of equations (1) and (2), the entire area of the reference image 60 may be treated as the transition area 63. In this case, α(x,y)=β for the entire area. In a modification, β may be 0<β<1 or may further include 0 and/or 1. FIG. 10 shows an example where β satisfies 0<β<1. In this case, an attenuated image (an image in which the contrast image 32 has been attenuated by the components of the mask image 31) is assigned to the entire area.

In addition, in this modification, α, that is, β It is recommended to set .

The medical image processing apparatus 10 according to the present embodiment includes a reference image 60 having a first region 61 showing a contrast image 32 and a second region 62 showing a contrast blood vessel 41a extracted from the contrast image 32. generate. Therefore, the device is depicted in the first region 61, and the contrast blood vessel 41a is clearly depicted in the second region 62. Therefore, according to the medical image processing apparatus 10, both the blood vessel running of the contrast-enhanced blood vessel 41a and the device can be clearly depicted in one reference image 60. Therefore, by checking the reference image 60, the user can easily and reliably grasp the positional relationship between the blood vessel direction and the device.

(Second embodiment)
FIG. 11 is a block diagram showing a configuration example of an X-ray diagnostic apparatus 80 including a medical image processing apparatus according to the second embodiment. The X-ray diagnostic device 80 includes an imaging device 81 that generates an X-ray image by taking an X-ray image of a subject, and a console device 82 as an example of the medical image processing device 10.

The X-ray diagnostic apparatus 80 according to the second embodiment differs from the medical image processing apparatus 10 according to the first embodiment in that it can photograph a subject and obtain a mask image 31 and a contrast image 32 by itself. Other configurations and operations are substantially the same as those of the medical image processing apparatus 10 shown in FIG. 1, so the same configurations are given the same reference numerals and description thereof will be omitted.

The imaging device 81 is composed of, for example, an imaging system of an X-ray angiography device, and includes an X-ray tube, an It has an imaging system including an imaging system, and provides an X-ray image obtained by X-ray imaging to the console device 82.

The X-ray image acquisition function 21x, the position acquisition function 22x, the DSA image generation function 23x, and the reference image generation function 24x of the processing circuit 15x of the console device 82 as an example of the medical image processing apparatus 10 are Since it has the same configuration and operation as the line image acquisition function 21, position acquisition function 22, DSA image generation function 23, and reference image generation function 24, the description thereof will be omitted.

Similarly to the medical image processing apparatus 10 according to the first embodiment, the X-ray diagnostic apparatus 80 including the console apparatus 82 as a medical image processing apparatus according to the second embodiment can provide a clear contrast image in one reference image 60. Both the course of the blood vessel 41a and the device can be visualized. Therefore, by checking the reference image 60, the user can easily and reliably grasp the positional relationship between the blood vessel direction and the device.

According to at least one embodiment described above, blood vessel running and a device can be depicted in one image.

In the above embodiments, the term "processor" refers to, for example, a dedicated or general-purpose CPU (Central Processing Unit), GPU (Graphics Processing Unit), or Application Specific Integrated Circuit (ASIC). Circuits such as programmable logic devices (e.g., Simple Programmable Logic Devices (SPLDs), Complex Programmable Logic Devices (CPLDs), and Field Programmable Gate Arrays (FPGAs)) means. When the processor is, for example, a CPU, the processor implements various functions by reading and executing programs stored in a storage circuit. Further, when the processor is, for example, an ASIC, instead of storing the program in a storage circuit, the function corresponding to the program is directly incorporated into the processor circuit as a logic circuit. In this case, the processor implements various functions through hardware processing that reads and executes programs built into the circuit. Alternatively, the processor can also implement various functions by combining software processing and hardware processing.

Furthermore, in the above embodiment, an example is shown in which a single processor of the processing circuit realizes each function, but a processing circuit may be configured by combining multiple independent processors, and each processor realizes each function. Good too. Furthermore, when multiple processors are provided, a memory circuit for storing programs may be provided individually for each processor, or a single memory circuit may collectively store programs corresponding to the functions of all processors. Good too.

Although several embodiments have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, changes, and combinations of embodiments can be made without departing from the gist of the invention. These embodiments and their modifications are included within the scope and gist of the invention as well as within the scope of the invention described in the claims and its equivalents.

10 Medical image processing device 21, 21x X-ray image acquisition function 22, 22x Position acquisition function 23, 23x DSA image generation function 24, 24x Reference image generation function 31 Mask image 32 Contrast image 33 DSA image 40 Lower limb 41 Blood vessel 41a Contrast blood vessel 42 Blood flow obstruction (CTO)
51 Guidewire 52 Microcatheter 52t Tip 60 Reference image 61 First region 62 Second region 63 Transition region 71 Boundary line 80 X-ray diagnostic device

Claims (15)

an X-ray image acquisition unit that acquires an X-ray image in which the device and contrast-enhanced blood vessels are depicted;
a reference image generation unit that generates a reference image having a first region showing the X-ray image and a second region showing the contrast-enhanced blood vessel extracted from the X-ray image;
A medical image processing device equipped with a position acquisition unit that acquires the position of at least a point of interest of the device;
Furthermore,
The reference image generation unit includes:
setting the first area and the second area based on the position of at least the point of interest of the device;
The medical image processing device according to claim 1. The device includes:
The first device is inserted into the blood vessel from the upstream side of the blood flow toward the blood flow obstruction, whereas the first device is inserted into the blood vessel from the downstream side of the blood flow toward the blood flow obstruction, and the tip is inserted into the blood vessel toward the blood flow obstruction. a second device located within the object;
The position acquisition unit includes:
obtaining the position of at least a tip of the second device;
The reference image generation unit includes:
setting the first region and the second region based on the position of at least the tip of the second device;
The medical image processing apparatus according to claim 2. The reference image generation unit includes:
setting the first region and the second region by setting a boundary line that crosses the reference image based on the position of the tip;
The medical image processing apparatus according to claim 3. The position acquisition unit includes:
obtaining the entire position of the second device depicted in the X-ray image;
The reference image generation unit includes:
setting the first region and the second region by setting the first region to include the entire second device and setting another region in the second region;
The medical image processing apparatus according to claim 3. The X-ray image acquisition unit includes:
Sequentially acquiring the X-ray images at a predetermined frame rate in real time,
The position acquisition unit includes:
updating the position of at least the tip of the second device each time the X-ray image is acquired;
The reference image generation unit includes:
setting the first region and the second region each time the X-ray image is acquired or each time the position of at least the tip of the second device is updated;
The medical image processing apparatus according to claim 4 or 5. The reference image generation unit includes:
Based on the contrast-enhanced blood vessels depicted in each of the plurality of X-ray images acquired in chronological order, the positions of all the contrast-enhanced blood vessels included in the reference image are identified, and all of the identified The first region and the second region are arranged such that the contrast blood vessel is included in the second region and at least the position of the tip of the second device is included in the first region. set,
The medical image processing apparatus according to claim 3. The device includes:
An embolic coil placed in the aneurysm as a result of coil embolization of the aneurysm,
The position acquisition unit includes:
obtaining the position of the embolic coil;
The reference image generation unit includes:
Based on the position of the embolic coil, the embolic coil is depicted in the first region showing the X-ray image, and the contrast blood vessel is depicted in the second region. setting a region and the second region;
The medical image processing apparatus according to claim 2. The reference image generation unit includes:
A transition region between the first region and the second region is set in the reference image, and in the transition region, the X-ray image is attenuated more strongly with the components of the mask image at positions closer to the second region. To generate an attenuated image,
A medical image processing apparatus according to any one of claims 1 to 8. The reference image generation unit includes:
generating a high frequency component image of the X-ray image in the first region;
A medical image processing apparatus according to any one of claims 1 to 9. The reference image generation unit includes:
In the first region, a high frequency component image of the X-ray image is generated, and in the transition region, the components of the mask image are attenuated more strongly at positions closer to the second region, and the generating the attenuated image so that the X-ray image is more strongly attenuated by the components of the high-frequency component image of the X-ray image at positions closer to the first region;
The medical image processing device according to claim 9. The second a DSA image generation unit that generates an image showing the contrast blood vessel used in the region;
The medical image processing device according to any one of claims 1 to 11, further comprising: The X-rays acquired by the X-ray image acquisition unit for a trained model that outputs an image showing the contrast-enhanced blood vessel depicted in the X-ray image based on the X-ray image in which the device and the contrast-enhanced blood vessel are depicted. a DSA image generation unit that generates an image showing the contrast blood vessel used in the second region by inputting an image;
The medical image processing device according to any one of claims 1 to 11, further comprising: an imaging device that generates an X-ray image in which the device and contrast blood vessels are depicted by taking an X-ray image of the subject;
an X-ray image acquisition unit that acquires the X-ray image taken by the imaging device;
a reference image generation unit that generates a reference image having a first region showing the X-ray image and a second region showing the contrast-enhanced blood vessel extracted from the X-ray image;
X-ray diagnostic equipment equipped with to the computer,
a step of obtaining an X-ray image in which a device and a contrast-enhanced blood vessel are depicted; and a first region showing the X-ray image and a second region showing the contrast-enhanced blood vessel extracted from the X-ray image. generating a reference image having
A medical image processing program for executing.

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