JP2010201044A - Medical image preparation instrument - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an image of a blood vessel readily by separating a bone area and a peripheral blood vessel adjacent to the bone area. <P>SOLUTION: A medical image preparation instrument acquires a three-dimensional raw image Io of a region including the bone and the proximate peripheral blood vessel into which a contrast medium is poured by a CT scanner. The instrument generates a reconstructed image Ir1 by processing the raw image Io by a smoothing function to smooth an image by computer image processing. The instrument generates a reconstructed image Ir2 by processing the raw image Io by an edge enhancement function. The instrument generates a reconstructed image Ir4 of the bone by processing the reconstructed image Ir2 by using a threshold value of the bone. By subtracting the reconstructed image Ir4 of the bone from the reconstructed image Ir1, the instrument obtains an image If of the peripheral blood vessel. The instrument arranges a slider bar on a screen, permitting the edge enhancement function to be continuously changed, and makes the processing of obtaining the image If of the peripheral blood vessel automatically repeated when the edge enhancement function is changed. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a medical image creation apparatus.

  2. Description of the Related Art A medical image obtained by imaging a subject's body using a CT apparatus (Computed Tomography) or the like is widely used for diagnosis of a subject's medical condition. By using the medical image for diagnosis, it is possible to grasp the progress state of the medical condition of the subject without causing external damage to the subject, and to obtain information necessary for determining the treatment policy.

  In recent years, since medical images have been digitized, it has become easy to perform image processing on medical images.

  Here, there is a problem that the original medical image obtained from the CT apparatus or the like is not easily detected even if a lesion is present in the medical image as it is. For this reason, diagnosis is performed using a bone-removed image obtained by extracting a bone from a medical image and removing the extracted bone. As a method of extracting bone, a method of extracting a region having an image density equal to or higher than a reference density as a bone region is widely known.

  However, in a contrast image taken with a contrast agent applied to the subject, the blood vessel region belonging to the blood vessel has a high image density like the bone region, and the bone region and the blood vessel region cannot be separated. is there.

  Therefore, before the contrast agent is injected and in a state where the contrast agent is injected, the subject is imaged, and a non-contrast image (simple CT image) is subtracted from the contrast image to obtain an image of the blood vessel region. The subtraction method has been put into practical use.

However, this method has a drawback in that at least two CT scans are indispensable before and after the administration of the contrast agent, and the exposure dose increases.
In this method, the calcification position also changes due to respiratory movement before and after the contrast, and there is a possibility that a false image of the lesion site is created.

  Japanese Patent Application No. 2008-74470 discloses an image processing method capable of solving the drawbacks of the conventional volume subtraction method. In this method, a contrast image is processed by a plurality of reconstruction functions to obtain a plurality of reconstruction images, and a difference between these images is obtained to obtain an image of a blood vessel region.

However, the reconstruction function suitable for acquiring a target image is slightly different for each object and image.
However, Japanese Patent Application No. 2008-74470 does not disclose a method for specifying an optimal reconstruction function. For this reason, it may take time to obtain an optimal image.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a medical image creation apparatus that can easily separate adjacent regions.

In order to achieve the above object, the medical image creation apparatus of the present invention comprises:
Storage means for storing a digital image of a region including a target portion imaged by a medical image imaging device;
Reconstruction means for processing a digital image stored in the storage means by a plurality of reconstruction functions to obtain a plurality of reconstructed images;
Image processing means for generating an image of the target portion based on a plurality of reconstructed images reconstructed by the reconstructing means;
A user interface that continuously changes the reconstruction function in response to a user operation;
Control means for causing the reconstruction means and the image processing means to regenerate an image of the target portion in response to a change in the reconstruction function;
It is characterized by providing.

  For example, the user interface may include means for displaying a slider bar, means for detecting an operation on the displayed slider bar, and at least one of the reconstruction function in response to the detected operation on the slider bar. And means for changing and setting.

  For example, a second user interface that changes a value in response to a user operation is further arranged, and the reconstruction unit adds the value set by the second user interface to the pixel value of the reconstructed image. Adding means for adding, wherein the control means causes the reconstruction means and the image processing means to regenerate the image of the target portion in response to a change in value by the second user interface. It may be configured.

  For example, the second user interface includes a means for displaying a second slider bar, a means for detecting an operation on the displayed second slider bar, and an operation on the detected second slider bar. And a means for changing and setting the value.

  For example, in response to a user operation, a third user interface that continuously changes the threshold value is arranged, and the reconstruction means includes means for processing the reconstructed image using the threshold value, and the control means May be configured to cause the reconstruction unit and the image processing unit to regenerate an image of the target portion in response to a change in the threshold value.

  For example, the third user interface includes a means for displaying a third slider bar, a means for detecting an operation on the displayed third slider bar, and an operation on the detected third slider bar. And a means for changing and setting the threshold value.

  For example, the digital image stored in the storage means is digital image data of a region including a bone and a blood vessel into which a contrast medium has been added, and the first reconstruction function among the plurality of reconstruction functions is: An image processing function, wherein the second reconstruction function is a function different from the first reconstruction function in enhancing an edge of the image, and the image processing means includes the first reconstruction function. Subtracting the density of the corresponding pixel constituting the second reconstructed image processed by the second reconstruction function from the density of each pixel constituting the first reconstructed image processed by And a unit for generating an image of a blood vessel by setting the density of the corresponding pixel of the user interface, wherein the user interface uses at least one of the first reconstruction function and the second reconstruction function as a user operation. In response To may be configured to.

  For example, the digital image stored in the storage means is a digital image of an area including a bone and a blood vessel into which a contrast medium has been injected, and the first reconstruction function among the plurality of reconstruction functions is: An image processing function, wherein the second reconstruction function is a function that differs from the first reconstruction function in terms of enhancing an edge of the image, and the reconstruction means includes the first reconstruction function. The first reconstructed image is formed by processing the digital image according to the above, the digital image is processed by the second reconstruction function, and each pixel of the obtained image is processed based on the second threshold value. A second reconstructed image is formed, and the user interface changes at least one of the first reconstruction function and the second reconstruction function in response to a user operation. It may be configured.

  For example, the reconstruction means is configured to generate the second reconstructed image, which is a bone image, by processing an image processed by the second reconstruction function using a bone threshold value. May be.

A computer program according to the second aspect of the present invention provides:
Computer
Storage means for storing a digital image of a region including a target portion imaged by a medical image imaging device;
Reconstructing means for processing a digital image stored in the storage means with a plurality of reconstruction functions to obtain a plurality of reconstructed images;
Image processing means for generating an image of the target portion based on a plurality of reconstructed images reconstructed by the reconstructing means;
A user interface that continuously changes the reconstruction function in response to a user operation;
Control means for causing the reconstruction means and the image processing means to regenerate an image of the target portion in response to a change in the reconstruction function;
It is made to function as.

  According to the present invention, it is possible to generate an image of a target portion while appropriately changing the reconstruction function, and it becomes easy to obtain an appropriate image.

1 is a configuration diagram of an image processing system according to an embodiment of the present invention. It is a figure which shows the internal structure of the medical terminal device shown in FIG. It is a figure which shows the structure of a memory | storage part. It is a figure for demonstrating a reconstruction function. It is a figure for demonstrating a reconstruction function, (a) shows an example of an original image, (b) is the frequency (edge emphasis degree) which a reconstruction function emphasizes, and the reconstruction processed by each reconstruction function It is a figure which shows the relationship of an image. It is a flowchart for demonstrating the process which produces | generates the image of the blood vessel. (A) is a figure which shows an example of the emphasis frequency designation | designated slider bar displayed on a screen, (b) is a figure which shows an example of the addition value designation | designated slider bar displayed on a screen. It is a figure which shows the specific example of the process which extracts the blood vessel, and the image produced | generated. It is a figure which shows the example of the change of the image accompanying the change of an edge enhancement function, and shows the example of the change of the blood vessel and bone image of the head and neck part accompanying the change of an edge enhancement function. It is a figure which shows the example of the change of the image accompanying the change of an edge enhancement function, and shows the example of the change of the image of the peripheral blood vessel accompanying the change of an edge enhancement function. It is a figure which shows the example of the change of the image accompanying the change of an edge emphasis function, and shows the example of the change of the image of a fracture line accompanying the change of an edge emphasis function. 12 is a flowchart for explaining another example of processing for generating a blood vessel image. It is a figure which shows the rotary knob as another example of a user interface. (A) is an example of a table associating an extraction target part with an edge enhancement function, and (b) is an example of a table associating an extraction target part and the degree of extraction with an edge enhancement function. It is a figure which shows the example which displays a some blood-vessel image.

Hereinafter, a medical system according to an embodiment of the present invention will be described with reference to the accompanying drawings.
As shown in FIG. 1, the medical system according to the present embodiment includes a CT apparatus 11, a medical information DB (database) 12, a medical terminal apparatus 13 (13 _{1 to} 13 _n ), and a communication network 14. ing.

  The CT apparatus 11 is a computed tomography apparatus, which scans a subject using radiation and processes it using a computer, thereby outputting a medical image of the subject, that is, voxel data of an internal image. . The value (CT value: density) of each pixel of the voxel data is high for the pixel corresponding to the bone region and relatively low for the pixel corresponding to the soft tissue.

  The medical information DB 12 stores medical images acquired by the CT apparatus 11 together with information such as medical records.

The medical terminal device 13 (13 _{1 to} 13 _n ) is composed of, for example, a workstation, and extracts attention areas or tissues for diagnosis from various medical data processing, for example, medical images acquired by the CT device 11. To generate and display the processed image. The generated image is also stored in the medical information DB 12 as necessary.

  The communication network 14 is a network installed in the hospital or in a wide area, and transmits data.

Next, the configuration of the medical terminal device 13 (13 _{1 to} 13 _n ) will be described.

  As illustrated in FIG. 2, the medical terminal device 13 includes a communication unit 21, a control unit 22, a storage unit 23, an input unit 24, and a display unit 25.

  The communication unit 21 transmits / receives various data (information) to / from an external device via the communication network 14.

  The control unit 22 includes a processor, a memory, and the like, and performs basic operations including input / output operations according to an OS (operating system) to control the entire medical terminal device 13. Further, the control unit 22 processes an image according to an image processing program installed in the storage unit 23 in advance. Note that the control unit 22 may include a processor dedicated to image processing and arithmetic processing.

  The storage unit 23 includes a semiconductor memory, a magnetic disk recording device, and the like, and records various types of information and programs. As illustrated in FIG. 3, the storage unit 23 generates, for example, an image processing program that executes image processing to be described later, a smoothing function for smoothing an image, and an edge enhancement function for enhancing an edge of the image. An edge enhancement function generation program, a medical image read from the medical information DB 12, data such as a medical image being processed, and the like are stored.

The smoothing function is a function that smoothes changes in CT values on an image by averaging the CT values of its own pixels and the CT values of surrounding pixels with a constant weight for each pixel constituting the original image.
The edge enhancement function generation program generates an edge enhancement function that is a function for enhancing a change in the CT value of a pixel.

  For example, when CT values on one scanning line on an image obtained by imaging a vertebra-vertebral artery-vertebra are processed with a smoothing function and an edge enhancement function, the result is as shown in FIG. In the present embodiment, the processing target is voxel data, and each function is for voxel data.

  Furthermore, by changing the edge enhancement function, the emphasized frequency also changes and the processing result also changes. For example, when the image shown in FIG. 5A is processed by changing the edge enhancement function (by changing the frequency to be emphasized), the processed image also changes as shown in FIG. 5B. In the example of FIG. 5B, the right image is processed with an edge enhancement function that enhances the edge (high frequency is enhanced), and the left image is emphasized (high frequency is enhanced). An example of processing with an edge enhancement function having a low degree (in other words, a high degree of smoothing (a high degree of emphasizing low frequencies)) is shown.

  The edge enhancement function generation program stored in the storage unit 23 illustrated in FIG. 3 generates an edge enhancement function having characteristics (frequency to be enhanced) designated by the user.

  The addition value generation program stored in the storage unit 23 illustrated in FIG. 3 is a program that determines a value to be added to the density (CT value) of each pixel constituting an image according to a user instruction. A method for generating the added value will be described later.

The input unit 24 shown in FIG. 2 includes a keyboard, a touch panel, and the like, and inputs arbitrary data / instructions. The input unit 24 includes a mouse 24M. The mouse 24M can click or drag and drop icons and buttons displayed on the screen in cooperation with an OS (operating system).
The display unit 25 is composed of an LCD (Liquid Crystal Display) or the like, and displays images and data.

Next, the operation of the medical system having the above configuration will be described.
The medical system of the present embodiment executes characteristic medical image processing described below together with operations that can be performed by a general medical system.
Hereinafter, this medical image processing will be mainly described.

(Acquisition of subject image)
First, a CT image of a subject in a state where a contrast agent is administered is taken by the CT apparatus 11. This CT image is transmitted to the medical information DB 12 together with patient information and the like via the communication network 14 and stored.

(Create and display blood vessel images)
Next, an operation in which the medical terminal device 13 processes the image acquired by the CT device 11 to acquire and display a three-dimensional image of the blood vessel, particularly an image of a region where the blood vessel and the bone are adjacent to each other. explain.

  The user operates the input unit 24 of the medical terminal device 13 and designates a medical image to be processed. In response to this operation, the control unit 22 communicates with the medical information DB 12 via the communication unit 21 and reads the target patient's original image (original image image data; voxel data) Io from the medical information DB 12. And stored in the storage unit 23.

  Subsequently, the control unit 22 starts the process shown in the flowchart of FIG. 6. First, on the display screen, the enhanced frequency designation slider bar 31 shown in FIG. 7A and the added value designation shown in FIG. 7B are displayed. The slider bar 33 is displayed (step S11).

  The enhancement frequency designation slider bar 31 shown in FIG. 7A continuously changes the degree of enhancement of the edge of the edge enhancement function (frequency to be enhanced) with a predetermined resolution by moving the “knob” 32 to the left and right. The slider bar for moving the “knob” 32 to the right increases the degree of emphasizing the edge (enhancement frequency), and the “knob” 32 is moved to the left to enhance the edge ( Frequency to be enhanced) and the degree of smoothing the image is increased. The edge enhancement function generation program generates an edge enhancement function having an enhancement frequency corresponding to the position of the “knob” 32.

  The added value designation slider bar 33 shown in FIG. 7B is for specifying a value (added value = K · CT value) to be added to the CT value of each voxel by moving the “knob” 34 to the left and right. This is a slider bar that continuously changes the coefficient K with a predetermined resolution. The coefficient K corresponds to the position of the “knob” 34 on the added value designation slider bar 33 in FIG. 7B. When the “knob” 34 is at the reference point, K = 0, and the closer to the right side, the more the coefficient K is located. The coefficient K increases with a positive value, and the closer to the left, the greater the absolute value with a negative coefficient K. The addition value generation program obtains a coefficient K corresponding to the position of the “knob” 34 and generates an addition value from the obtained K and the CT value of each pixel.

  The user can operate (drag: move) the “knobs” 32 and 34 of the slider bars 31 and 33 by operating the mouse 24M. The control unit 22 detects the operation of the mouse 24M by the function of the OS, and moves the “knobs” 32 and 34 on the slider bars 31 and 33 on the display screen.

  Subsequently, the control unit 22 smoothes the read voxel data using a smoothing function stored in the storage unit 23, and generates a reconstructed image Ir1 (step S12). Specifically, the control unit 22 uses the operator corresponding to the smoothing function to calculate the CT value (density) of the pixel and the surrounding pixels for the pixel at the coordinates (x, y, z) of the original image Io. An average is obtained by weighted addition to obtain a CT value of coordinates (x, y, z) of the reconstructed image. The control unit 22 performs this operation for all pixels in the original image to generate a reconstructed image Ir1.

  Subsequently, the control unit 22 specifies the edge enhancement degree indicated by the “knob” 32 of the displayed enhancement frequency designation slider bar 31 and generates an operator corresponding to the corresponding edge enhancement function (step S13). . That is, the control unit 22 specifies the position of the “knob” 32 on the emphasis frequency designation slider bar 31 in FIG. 7A, and the degree of emphasizing the edge of the image as the “knob” 32 is located on the right side. The operator is generated such that the higher the “knob” 32 is on the left side, the higher the degree of smoothing the edge of the image.

  Next, the control unit 22 processes the original image using the generated operator (step S13). Specifically, using the generated operator, the control unit 22 emphasizes the difference (Δ) in the CT value of the pixel adjacent to the pixel (x, y, z) of the original image Io ( k · Δ) to obtain the CT value of the coordinates (x, y, z) of the reconstructed image. The control unit 22 performs this operation for all the pixels in the original image, and generates a new reconstructed image Ir2.

  Next, the control unit 22 specifies the CT value of each pixel of the generated bone reconstructed image Ir2, specifies the coefficient K corresponding to the position of the “knob” 34 of the added value designation slider bar 33, and adds the added value. The K · CT value is obtained, the obtained addition value is added to the CT value of the pixel, and the addition result (1 + K) · CT value is set as a new CT value. The control unit 22 performs this operation for all the pixels in the reconstructed image Ir2, and generates a new reconstructed image Ir3 (step S14). As described above, when the “knob” 34 on the added value designation slider bar 33 in FIG. 7B is at the reference point, the coefficient K is positive as the coefficient K is located at the right side. The larger the value is, the closer to the left side, the larger the absolute value with a negative coefficient K.

  Subsequently, the control unit 22 processes the reconstructed image Ir3 obtained in step S14 with a bone threshold value, and extracts a bone reconstructed image Ir4 (step S15). Specifically, for each pixel of the reconstructed image Ir3 obtained in step S14, the control unit 22 pays attention to the CT value corresponding to a predetermined bone (for example, different for each bone. CT value corresponding to the bone to be boned) or higher, and if it is equal to or higher than the bone threshold value, it is maintained as equivalent to the bone, and if it is lower, the CT value is set to 0 and the process is made transparent I do. The control unit 22 performs this operation for all the pixels in the reconstructed image Ir3, and generates a new reconstructed image Ir4.

  Next, the control unit 22 subtracts the bone reconstructed image Ir4 generated in step S15 from the reconstructed image Ir1 generated in step S12 to generate a result image If (step S16). Specifically, the control unit 22 subtracts the CT value of the corresponding coordinate (x, y, z) of the reconstructed image Ir4 from the CT value of the pixel of the coordinate (x, y, z) of the reconstructed image Ir1. Then, the result image If is generated using the subtraction result as the CT value of the coordinates (x, y, z) of the result image If. The result image If is obtained by subtracting the reconstructed image Ir4 of the bone in which the edge is enhanced and a predetermined CT value is added from the reconstructed image Ir1, and is an image that clearly represents the blood vessel.

  The control unit 22 displays the result image If thus obtained on the display unit 25 (step S17). Also, save as necessary.

  Next, the control unit 22 determines whether or not the “knob” 32 of the emphasis frequency designation slider bar 31 and the “knob” 34 of the addition value designation slider bar 33 have been operated (step S18).

  If at least one of the slider bars 31 and 33 is operated (step S18; Yes), the process returns to step S12, and the same processing as described above is executed using the specified edge enhancement function or addition value. The image If is displayed.

  When there is no operation of the “knobs” 32 and 33 of the slider bars 31 and 33 (step S18; No), the control unit 22 determines whether or not the end of the process or another process is instructed (step S19).

  If the end of the process is not instructed (step S19; No), the process returns to step S18 to wait for the instruction.

  On the other hand, if the end of the process or the start of another process is instructed (step S19; Yes), the current process ends.

  According to such a configuration, the user evaluates the result image If displayed on the screen, that is, the blood vessel image, and if necessary, the “knob” 32 of the enhancement frequency designation slider bar 31 and the addition value designation slider bar. The blood vessel image can be generated and displayed again by appropriately operating the “knob” 33 and appropriately changing the characteristics of the edge enhancement function and the added value. For this reason, it is possible to easily obtain an optimal blood vessel image by operating the “knobs” 32 and 34 of the slider bars 31 and 33 while observing the displayed result image If.

  Further, the edge enhancement function and the threshold value can be changed for each displayed image. Conventionally, for example, in the case of the head and neck, the whole is processed with a specific edge enhancement function. Therefore, bones and blood vessels can be separated in the head, but in the vicinity of the shoulder, there are problems such as difficulty in separating bones and blood vessels, but in this embodiment, the head is the head while changing the slider bar, The neck can separate bones and blood vessels at the neck. Therefore, it is possible to appropriately separate bones and blood vessels regardless of the region of interest.

FIG. 8 shows an example of each image obtained in this way.
First, the original image Io is a view when a three-dimensional CT image of a human body including the neck is viewed from the side.
The reconstructed image Ir1 is an image obtained by smoothing the original image Io using a smoothing function, and there is not much change in appearance. The reconstructed image Ir2 is an image obtained by processing the original image Io using an edge enhancement function and enhancing edges. The degree of emphasizing the edge (the frequency to be emphasized) varies depending on the position of the “knob” 32 on the emphasis frequency designation slider bar 31.

  In the reconstructed image Ir3, an addition value K · CT value determined by a coefficient K corresponding to the position of the “knob” 34 on the addition value designation slider bar 33 is added to the CT value of each pixel of the reconstructed image Ir2. A reconstructed image Ir3 is generated, and the reconstructed image Ir3 is processed using a bone threshold value to obtain a bone reconstructed image Ir4.

  The image If is a result of subtracting the bone reconstructed image Ir4 from the reconstructed image Ir1, and blood vessels are appropriately extracted despite being adjacent to the bone.

  9 to 11 show processing examples of the image processing apparatus according to the present embodiment.

First, FIG. 9 shows an example of a result image of blood vessels and bones in the head and neck region.
In this example, for the subject A, when high frequency is emphasized, the noise in the shoulder portion becomes large. Therefore, while observing the result image If, the “knob” 32 of the emphasis frequency designation slider bar 31 is operated to change the edge emphasis function to emphasize the low frequency, thereby removing noise. On the other hand, in the subject B, a sufficiently high quality image is obtained even at the shoulder portion by emphasizing the high frequency.

  In this way, a clear image can be easily obtained by operating the “knob” 32 of the enhancement frequency designation slider bar 31 in accordance with the part or the subject to change the edge enhancement function.

  FIG. 10 shows changes in peripheral blood vessel images accompanying changes in the edge enhancement function. In this example, when the “knob” 32 of the emphasis frequency designation slider bar 31 is operated to emphasize the high frequency, the result image If where the thin peripheral blood vessels are clearer is obtained.

  Further, FIG. 11 shows a change in the image of the fracture line accompanying a change in the edge enhancement function. As shown in the drawing, by operating the “knob” 32 of the emphasis frequency designation slider bar 31 and emphasizing the high frequency, a result image If with a clear fracture line is obtained.

  Thus, in the present embodiment, an appropriate image can be obtained by operating the “knobs” 32 and 34 of the enhancement frequency designation slider bar 31 and the addition value designation slider bar 33 while observing the result image If. it can.

(Modification)
The present invention is not limited to the above embodiment, and various modifications and applications are possible.
In the above embodiment, the slider bars 31 and 33 are arranged. However, for example, only the emphasized frequency designation slider bar 31 may be arranged.

  Further, for example, in the above embodiment, when extracting the bone, attention is paid to the CT value of each pixel, and if the CT value exceeds the threshold value, the bone is extracted. It may be extracted. For example, using a bone as a starting point (the starting point is specified by an operator, for example), the pixels are traced, and the CT values of adjacent pixels within a predetermined range (for example, 6 points up and down, left and right, and 12 points in the vicinity) are threshold values. As described above, if the CT value of the adjacent pixel is within ± 100, the pixel may be selected, and the pixel to be extracted may be specified by scanning the pixel.

  Further, since the threshold value is set for the bone extracted in this way, the volume of the entire bone may be reduced. In such a case, the process shown in FIG. 12 is effective.

  In this case, the control unit 22 first reads the original image Io (step S21), and smoothes the original image Io to generate a reconstructed image Ir1 (step S22).

  Next, the control unit 22 processes the original image Io using the edge enhancement function, and generates a reconstructed image Ir2 with the edge enhanced (step S23). The degree of edge enhancement can be arbitrarily set by the user, for example, by operating the “knob” 32 of the enhancement frequency designation slider bar 31.

  Next, the product K · CT value of the coefficient K and the CT value specified by the position of the “knob” 34 of the addition value designation slider bar 33 is added as an addition value to the CT value of each pixel of the reconstructed image Ir2. A reconstructed image Ir3 is generated, and the reconstructed image Ir3 is processed using the bone threshold value to generate a reconstructed image Ir4 of the bone (step S24).

  Next, the control unit 22 subtracts the bone reconstructed image Ir4 from the reconstructed image Ir2 with the edge enhanced to generate a reconstructed image Ir5 (step S25). That is, the CT value of the pixel at the coordinate (x, y, z) of the bone reconstructed image Ir4 generated in step S24 is subtracted from the CT value of the pixel at the coordinate (x, y, z) of the reconstructed image Ir2. The CT value of the pixel at the coordinates (x, y, z) of the new image is used. The reconstructed image Ir5 obtained by subtraction is an image in which blood vessels and soft tissue remain.

  The control unit 22 sets a blood vessel threshold for the reconstructed image Ir5, extracts only the blood vessel, and generates a reconstructed image Ir6 of the blood vessel (step S26). In this case, for example, starting from a blood vessel (the start point is specified by an operator, for example), the pixels are sequentially traced to set the CT value threshold to an appropriate value of 100 (depending on the contrast agent concentration), and the CT value is the threshold value. As for the pixels exceeding the threshold value, the CT values of adjacent pixels within a predetermined range (for example, 6 points in the vertical and horizontal directions, or 12 points in the vicinity) are equal to or greater than the threshold value, and the difference in CT values from adjacent pixels is ± 100. If it is within the range, the process of selecting a blood vessel is executed while scanning the pixels.

  Next, the control unit 22 subtracts the reconstructed image Ir6 of the blood vessel thus extracted from the reconstructed image Ir2 with the edge enhanced (step S27). Thereby, the remaining reconstructed image Ir7 is an image of bone and soft tissue.

  Next, with respect to the reconstructed image Ir7 of bone and soft tissue, the control unit 22 sequentially follows the pixels with the start point being a pixel of the bone (for example, specified by the operator), and the threshold is 100 or more. When the CT value of the selected pixel is within ± 200, by selecting the pixel, a reconstructed image Ir8 of a bone having a volume including cartilage is generated (step S28).

  Next, the control unit 22 subtracts the obtained reconstructed image Ir8 from the reconstructed image Ir1, thereby generating a reconstructed image Ir9 of a blood vessel with a smooth edge (step S29), and displays it (step S29). Step S30).

  Next, the control unit 22 determines whether or not the “knob” 32 of the emphasis frequency designation slider bar 31 and the “knob” 34 of the addition value designation slider bar 33 have been operated (step S31).

  If the “knobs” 32 and 34 of at least one of the slider bars 31 and 33 are operated (step S31; Yes), the process returns to step S22 and the same as described above using the specified edge enhancement function or addition value. The blood vessel reconstruction image Ir9 is generated.

  When there is no operation of the “knobs” 32 and 34 of any of the slider bars 31 and 33 (step S31; No), the control unit 22 determines whether or not the end of the blood vessel image generation process 2 or another process is instructed. (Step S32).

  If the end of the process or the start of another process is not instructed (step S32; No), the process returns to step S31 and waits for the instruction.

  On the other hand, if the end of the process or the start of another process is instructed (step S31; Yes), the current process ends.

  Even in such a configuration, for example, by operating the “knobs” 32 and 34 of the slider bars 31 and 33 while observing the result image If, the edge enhancement function and the addition value are continuously changed, and the optimum It is possible to easily generate a result image If.

  In the above description, the embodiment has been described in which the edge enhancement function and the addition value can be changed continuously. The present invention is not limited to this. For example, the degree of smoothing of the smoothing function may be continuously changed. Further, the threshold value used for bone extraction, blood vessel extraction, and the like may be continuously changed. The image processing may be automatically performed each time the smoothing function or the threshold value changes to obtain a result image If.

Furthermore, although an example in which a slider bar is displayed and the edge enhancement function, the addition value, the smoothing function, and the threshold value are continuously changed has been shown, these may be changed using any other user interface. For example, a rotary knob as illustrated in FIG. 13 may be displayed, and these may be controlled by controlling the amount of rotation of the rotary knob.
Further, the indicated value may be a digital value with a fixed resolution.

  An edge enhancement function, a smoothing function, an added value, a threshold value, and the like suitable for extraction of a target part are usually determined to some extent depending on the target part. Therefore, the initial position of the user interface may be obtained in advance for each target part and automatically set when the target part is designated.

  For example, a part to be extracted and an edge enhancement function suitable for extraction of the part are obtained in advance by an experiment or the like, and a correspondence table is stored in the storage unit 23 as shown in FIGS. 14 (a) and 14 (b). When the image is processed, when the extraction part and the degree of extraction (the diameter of the blood vessel to be extracted, etc.) are input from the input unit 24, the control unit 22 refers to this table and determines the position of the “knob” 32. You may make it correct automatically in an appropriate position.

  Further, a plurality of images generated in accordance with the movement of the “knob” may be displayed in parallel (or sequentially) as illustrated in FIG.

In the above-described embodiment, the example of separating a bone from a nearby blood vessel has been mainly described. However, the present invention can be widely applied when a region having a different CT value is separated from another.
Further, although the CT apparatus is exemplified as the modality, other medical imaging apparatuses may be used. However, the present invention is particularly effective for an imaging apparatus that uses radiation for imaging and a system and method for processing an image acquired by this type of imaging apparatus from the viewpoint of suppressing the exposure dose.

  In the above description, a medical system that consistently performs from imaging to image processing / display has been described as an example. However, the present invention can implement only the image processing method portion of the image processing apparatus. Further, a general stand-alone computer, a network computer, a workstation, and the like store a computer program for executing the above-described image processing in a recording medium, distribute it, install and execute the computer program, You may make it perform the above-mentioned image processing.

Alternatively, a system for automatically calculating the optimum addition value and the optimum function by placing a selective region of interest in the image to be separated and profiling that region.
In addition, the device configuration, the flowchart, specific functions and numerical values can be changed as appropriate.

11 CT apparatus 12 Medical information DB
13 Medical terminal device 14 Communication network 21 Communication unit 22 Control unit 23 Storage unit 24 Input unit 24M Mouse 25 Display unit 31 Emphasized frequency designation slider bar 32 Knob 33 Addition value designation slider bar 34 Knob

Claims (10)

Storage means for storing a digital image of a region including a target portion imaged by a medical image imaging device;
Reconstruction means for processing a digital image stored in the storage means by a plurality of reconstruction functions to obtain a plurality of reconstructed images;
Image processing means for generating an image of the target portion based on a plurality of reconstructed images reconstructed by the reconstructing means;
A user interface that continuously changes the reconstruction function in response to a user operation;
Control means for causing the reconstruction means and the image processing means to regenerate an image of the target portion in response to a change in the reconstruction function;
A medical image creating apparatus comprising: The user interface is
Means for displaying a slider bar;
Means for detecting an operation on the displayed slider bar;
Means for changing and setting at least one of the reconstruction functions in response to an operation on the detected slider bar;
The medical image creation apparatus according to claim 1, further comprising: A second user interface for changing a value in response to a user operation;
The reconstructing means includes an adding means for adding a value set by the second user interface to a pixel value of the reconstructed image,
The control means causes the reconstruction means and the image processing means to regenerate an image of the target portion in response to a change in value by the second user interface.
The medical image creation apparatus according to claim 1 or 2. The second user interface is:
Means for displaying a second slider bar;
Means for detecting an operation on the displayed second slider bar;
Means for changing and setting the value in response to an operation on the detected second slider bar;
The medical image creation apparatus according to claim 3, further comprising: A third user interface for continuously changing the threshold in response to a user operation;
The reconstruction means comprises means for processing the reconstructed image using a threshold value,
The control unit causes the reconstruction unit and the image processing unit to regenerate an image of the target portion in response to the change in the threshold value.
The medical image creation apparatus according to claim 1 or 2. The third user interface is:
Means for displaying a third slider bar;
Means for detecting an operation on the displayed third slider bar;
Means for changing and setting the threshold value in response to the detected operation on the third slider bar;
The medical image creation apparatus according to claim 5, further comprising: The digital image stored in the storage means is digital image data of an area including a bone and a blood vessel into which a contrast medium is injected,
Of the plurality of reconstruction functions, the first reconstruction function is a function for processing an image, and the second reconstruction function is different from the first reconstruction function in that the edge of the image is enhanced. Function,
The image processing means composes a second reconstructed image processed by the second reconstruction function from the density of each pixel constituting the first reconstructed image processed by the first reconstruction function. A means for generating a blood vessel image by subtracting the corresponding pixel density to obtain the corresponding pixel density of the blood vessel image,
The user interface changes at least one of the first reconstruction function and the second reconstruction function in response to a user operation.
The medical image creation apparatus according to any one of claims 1 to 6. The digital image stored in the storage means is a digital image of a region including bone and a blood vessel into which a contrast medium has been introduced,
Of the plurality of reconstruction functions, the first reconstruction function is a function for processing an image, and the second reconstruction function is different from the first reconstruction function in that the edge of the image is enhanced. Function,
The reconstruction means forms a first reconstructed image by processing the digital image with the first reconstruction function, processes the digital image with the second reconstruction function, and obtains the obtained image Are processed based on a second threshold value to form a second reconstructed image,
The user interface changes at least one of the first reconstruction function and the second reconstruction function in response to a user operation.
The medical image creation apparatus according to claim 1, wherein the medical image creation apparatus is a medical image creation apparatus. The reconstruction means generates the second reconstructed image, which is a bone image, by processing the image processed by the second reconstruction function using a bone threshold value.
The medical image creation apparatus according to claim 7 or 8, wherein Computer
Storage means for storing a digital image of a region including a target portion imaged by a medical image imaging device;
Reconstructing means for processing a digital image stored in the storage means with a plurality of reconstruction functions to obtain a plurality of reconstructed images;
Image processing means for generating an image of the target portion based on a plurality of reconstructed images reconstructed by the reconstructing means;
A user interface that continuously changes the reconstruction function in response to a user operation;
Control means for causing the reconstruction means and the image processing means to regenerate an image of the target portion in response to a change in the reconstruction function;
A computer program that functions as a computer program.