JP4130118B2 - Image display apparatus, X-ray CT apparatus, program, and storage medium - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image display apparatus including a plurality of display units that display a plurality of X-ray tomographic images obtained by performing a fluoro scan on a subject punctured with a needle, a control method thereof, a program code, and a storage medium. Is.
[0002]
[Prior art]
In a diagnosis called real-time fluoroscopy using a radiation tomography system of an X-ray CT system, a region of interest (region of interest; ROI, Region of Ineterest, etc.) such as an affected part of a patient (subject) The needle is punctured for the purpose of injecting drugs or taking out part of the tissue. The operator confirms the position of the needle from the X-ray tomographic image of the subject after puncturing the needle.
[0003]
When the needle is used for the above-mentioned purpose, the operator needs to confirm the position of the needle, particularly the position of the tip of the needle, from the obtained X-ray tomographic image. A display example of the obtained X-ray tomogram is shown in FIG.
[0004]
In FIG. 3A, 301 is an X-ray tube, and 302 is a detector array of four rows. FIG. 3B shows a case where the four detector rows 302 shown in FIG. 3A are divided into three detector groups A, B, and C in the direction in which the subject is conveyed (hereinafter referred to as the z-axis direction). Shows an example of display of X-ray tomograms obtained by each detector group. The detector group B includes two detector rows, and two images are obtained from this detector group. The two images are combined and displayed on the screen of FIG. .
[0005]
3 (c) shows a case where the four detector rows 302 shown in FIG. 3 (a) are divided into two detector groups D and E in the direction in which the subject is conveyed (hereinafter referred to as the z-axis direction). The example of a display of the X-ray tomogram obtained by each detector group is shown. The detector groups D and E each include two detector rows. Similar to the detector group B described above, the images from the two detector rows included are combined and displayed. To do. For example, two images obtained from two rows of detectors belonging to the detector group D are combined and displayed on the screen shown in FIG.
[0006]
[Problems to be solved by the invention]
Conventionally, however, a plurality of X-ray tomographic images of the subject can be obtained, and display examples shown in FIGS. 3 (b) and 3 (c) particularly in CT fluoroscans that require real-time characteristics (real-time characteristics). Then, it has been troublesome to instantaneously find out which detector group displays the needle image on the screen. Even if the displayed screen is known, it is difficult to specify the position of the tip of the needle in the tomographic image.
[0007]
As described above, since the needle punctures the region of interest, in order to puncture the needle accurately and safely to the region of interest, the operator always determines the positional relationship between the tip of the needle and the region of interest. It is necessary to grasp.
[0008]
The present invention has been made in view of such problems, and an object thereof is to notify an operator of a screen on which a needle tip is displayed.
[0009]
Another object of the present invention is to notify the operator of a message according to the positional relationship between the tip of the needle and the region of interest.
[0010]
[Means for Solving the Problems]
In order to achieve the object of the present invention, for example, an image display apparatus of the present invention comprises the following arrangement.
[0011]
That is, an image display device including a plurality of display units for displaying X-ray tomographic images obtained by performing a fluoro scan on a subject punctured with a needle,
Detection means for detecting an end point of the needle from an X-ray tomographic image including an image of the needle;
A notifying unit for identifying a display unit on which the end points of the needles detected by the detecting unit are displayed in the plurality of display units, and notifying the display unit;
It is characterized by providing.
[0012]
In order to achieve the object of the present invention, for example, an image display apparatus of the present invention comprises the following arrangement.
[0013]
That is, an image display device including a plurality of display units for displaying X-ray tomographic images obtained by performing a fluoro scan on a subject punctured with a needle,
An X-ray tomogram including an image of the needle,
Three-dimensional continuous region extraction means for binarizing a three-dimensional image that is a set of the X-ray tomographic images, performing a three-dimensional labeling process, and extracting a three-dimensional continuous region;
According to the result of the three-dimensional labeling process, an area estimated as a three-dimensional continuous area of the needle is identified from the three-dimensional image, and the image is based on ellipsoidal approximation information or rectangular parallelepiped approximation information including the area. A determination means for determining whether the image is a needle image;
Detecting means for detecting an end point of the needle from the image determined as the needle image by the determining means;
A notifying unit for identifying a display unit on which the end points of the needles detected by the detecting unit are displayed in the plurality of display units, and notifying the display unit;
It is characterized by providing.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an image display device according to the present invention will be described in detail according to a preferred embodiment applied to an operation console with reference to the attached drawings.
[0015]
[First Embodiment]
FIG. 1 is a block diagram of the X-ray CT system of this embodiment. As shown in the figure, the present system includes a gantry apparatus 100 that integrally attaches an X-ray irradiation to a subject and an X-ray detection mechanism for detecting X-rays transmitted through the subject, and various operations on the gantry apparatus 100. The operation console 200 is configured to perform setting and reconstruct and display an X-ray tomogram based on data output from the gantry apparatus 100.
[0016]
The gantry apparatus 100 has the following configuration including the main controller 1 that controls the entire system.
[0017]
2 is an interface for communicating with the operation console 200, and 3 has a cavity for transporting a subject (patient) lying on the table 12 (hereinafter also referred to as z-axis in a direction perpendicular to the drawing). The gantry includes an X-ray generation source that is driven and controlled by an X-ray tube controller 5, a collimator 6 having a slit for controlling an X-ray irradiation range, and a collimator 6. A motor 7a, which is a slit width adjusting motor for controlling the X-ray irradiation range, is provided. The driving of the motor 7a is controlled by the collimator controller 7.
[0018]
The gantry 3 is obtained from an X-ray detector 8 that is a multi-detector composed of a plurality of detectors that detect X-rays that have passed through the subject, and transmitted X-rays obtained by the X-ray detector 8. A data collection unit 9 that collects projection data is also provided. The X-ray tube 4 and the collimator 6 and the X-ray detection unit 8 are provided at positions facing each other with the cavity portion interposed therebetween, that is, with the subject interposed therebetween, and rotate around the gantry 3 while maintaining the relationship therebetween. It comes to exercise. This rotational movement is performed by the rotary motor 10 driven by a drive signal from the motor controller 11. The table 12 on which the subject is placed is transported in the z-axis direction, and is driven by the table motor 13.
[0019]
The main controller 1 analyzes various commands received via the interface 2, and based on the analysis, the X-ray tube controller 5, collimator controller 7, motor controller 11, table motor controller 14, and data collection unit 9 On the other hand, various control signals are output. The projection data collected by the data collection unit 9 is sent to the operation console 200 via the data input interface 60.
[0020]
The operation console 200 is a so-called workstation, and includes a CPU 51 that controls the entire apparatus, a ROM 52 that stores a boot program, and a RAM 53 that functions as a main storage device as shown in the figure.
[0021]
The HDD 54 is a hard disk device for giving various instructions to the gantry apparatus 100 and reconstructing an X-ray tomographic image based on data received from the gantry apparatus 100 in addition to the OS and a scan control program described later. The program is stored. In addition, a program code for displaying an image, which will be described later, is also stored. The VRAM 55 is a memory for developing image data to be displayed, and can be displayed on the CRT 56 or CRT 61 by developing the image data or the like here. The CRT 61 is provided at a position where an operator who performs needle puncture can view the display screen.
[0022]
Reference numerals 57 and 58 denote a keyboard and a mouse for performing various settings. Reference numeral 59 denotes an interface for communicating with the gantry apparatus 100.
[0023]
Next, a method for obtaining an X-ray tomographic image of a subject using the X-ray CT system having the above configuration and specifying a needle image from the X-ray tomographic image will be described. As a scanning method for obtaining an X-ray tomographic image, a fluoro scan capable of displaying a tomographic image in real time is used.
[0024]
FIG. 2 shows a three-dimensional image composed of a plurality of X-ray tomographic images of the subject obtained by the above-described X-ray CT system. Reference numeral 201 denotes a three-dimensional image which is a set of X-ray tomographic images of a subject obtained by the number of detector rows in the z-axis direction, and is an image in which each pixel is three-dimensionally arranged. Reference numeral 202 denotes a needle image (three-dimensional continuous region). In the following, in order to obtain the needle image 202 from the three-dimensional image 201, the three-dimensional image 201 is binarized within an appropriate CT value range and then subjected to a three-dimensional labeling process.
[0025]
FIG. 4 shows a functional configuration of the three-dimensional labeling apparatus according to this embodiment. A three-dimensional image 401 that is a binary image is read by the reading unit 402 for each two-dimensional plane (the definition of the two-dimensional plane is as described above). The selector 404 selects pixel data used in a labeling unit 405 described later from the reading unit 402 and outputs the selected pixel data to the labeling unit 405. A labeling unit 405 performs labeling using pixel data selected by the selector 404 and a neighborhood mask described later. Then, three-dimensional labeling information for each two-dimensional plane is generated, and connection information (details will be described later) for each label is generated and output to the label connection information storage unit 406. The label connection information storage unit 406 stores the label connection information from the labeling unit 405 and outputs the label connection information to the re-labeling unit 407 described later. The re-labeling unit 407 configures a labeled three-dimensional image using label connection information.
[0026]
A labeling process performed by the three-dimensional labeling apparatus of the present embodiment having the above functional configuration will be described below.
[0027]
6A and 6B show the configuration of the three-dimensional neighborhood mask used for the labeling process in the present embodiment. The three-dimensional neighborhood mask in this embodiment has two layers, and has a configuration in which the neighborhood mask shown in FIG. 6A is superimposed on the upper portion of the neighborhood mask shown in FIG. 6B (in the direction of the arrow in FIG. 6B). . When the above-described two neighboring masks are overlapped, they are overlapped so that the positions of the pixel 602 shown in FIG. 6A and the pixel 603 shown in FIG. In this embodiment, as shown in FIG. 6C, a 26-neighboring three-dimensional neighborhood mask is used that refers to a total of 26 pixels including the upper 9 pixels, the surrounding 8 pixels, and the lower 9 pixels around the target pixel. The pixel 601 shown in FIG. 6A is hereinafter referred to as a target pixel (details will be described later).
[0028]
FIG. 8 shows each two-dimensional plane and three-dimensional neighborhood mask when performing a three-dimensional labeling process using the above-described three-dimensional neighborhood mask of the present embodiment. In the figure, 801a, 801b, and 801c are two-dimensional planes (binary images), and 802 is the upper part of the neighborhood mask shown in FIG. 6B (when the scanning proceeds in the direction of larger z-axis coordinates, 803 is the lower part of the neighborhood mask shown in FIG. 6A, and 803a is the target pixel (pixel 601 in FIG. 6).
[0029]
Hereinafter, a case where labeling processing is performed on each pixel included in the two-dimensional plane 801b will be described. However, the labeling processing described here is performed on all the two-dimensional planes (for example, two-dimensional planes 801a and 801b) constituting the three-dimensional image. , 801c) clearly includes performing a labeling process on the three-dimensional image. That is, this neighborhood mask is scanned three-dimensionally in the order of the x, y, and z axes. In the present embodiment, scanning is first performed in the x-axis direction, then the y-coordinate is advanced, and scanning is performed in the x-axis direction, and after completion of scanning of the xy plane, the next z-axis coordinate is advanced. That is, as shown in FIG. 8, scanning is performed in the order of scanning 1-1, 1-2, 1-3, 2-1, 2-2, 2-3.
[0030]
First, scanning is performed for each pixel in the x-axis direction from the pixel of x = 0, y = 0, z = 0 in the upper left corner of the plane 801b, and a pixel having a pixel value of 1 is searched. When scanning is performed to the right end, scanning is performed again from the left end (x = 0) of the row one stage below the y coordinate. Note that the position of the first pixel to be scanned and the scan direction are not limited to this. The label number of the first pixel found (the pixel value of the pixel of interest is 1) is set to 1. Thereafter, when a pixel having a pixel value of 1 is found (if the pixel value of the pixel of interest is 1), each pixel that has already been scanned in each of the neighboring masks (802 and 803) around the pixel of interest (each mask) Refer to the label number of the pixel and each pixel one-to-one.
[0031]
If the pixel in the neighborhood mask has a label number i for a pixel other than the pixel of interest, the label number of the pixel of interest is i.
[0032]
On the other hand, when a plurality of label numbers i, k, m are attached to pixels other than the pixel of interest in the neighborhood mask, in the present embodiment, the smallest number among the label numbers i, k, m is selected. The label number of the target pixel is used. In this case, the connection information (label connection information) indicating that the pixels having the label numbers i, k, and m (including the target pixel) are all three-dimensionally connected for re-labeling is generated.
[0033]
This connection information will be described with reference to FIG. FIG. 10 shows a case where different label numbers are given according to the priority in the direction of three-dimensional scanning, even though they are the same image area in the two-dimensional plane 1000, the image areas are connected and re-labeled. It is a figure for demonstrating the process which attaches the same label number in a process. In FIG. 10, different label numbers (1, 3) are assigned to the image areas 1001 and 1002 even though they are the same image area. Such a state may occur in the labeling process in the present embodiment. The above connection information is information indicating that the areas 1001 and 1002 are included in the same image area, and the description method of the information is not particularly limited. By referring to this connection information, the region 1001 and the region 1002 are connected, and the same label number (for example, the smallest number among the label numbers of each other) is given by the re-labeling process, thereby one region 1003. (See the figure on the right side of FIG. 10).
[0034]
Further, if the values of the pixels other than the pixel of interest in the neighborhood mask are all 0, that is, if any of the pixels (other than the pixel of interest) in the neighborhood mask has no label number, A label number obtained by adding 1 to the largest label number assigned in the labeling process is set as the label number of the target pixel.
[0035]
Thereafter, the above-described labeling process is performed on the target pixel while scanning all the pixels in the plane 801b. As a result, labeling information for the plane 801b can be created.
[0036]
When the three-dimensional labeling process is completed for all the pixels in the plane 801b, the process proceeds to the next plane 801c, and the above-described three-dimensional labeling process is performed on the plane 801c. In that case, the selector 404 reads the plane 801c next to the plane 801b from the reading unit 402 and outputs it to the labeling processing unit 405, so that the labeling processing unit 405 uses the planes 801b and 801c to display the pixels included in the plane 801c. Perform the labeling process.
[0037]
As a result of the above labeling processing, the label number of the target pixel (the target pixel in the above example) included in the target plane (in the above example, plane 801b) is within the vicinity of the upper plane (the plane 801a in the above example). Since it is determined by the value of the pixel included in the mask or the label number, when the labeling process is finished for all the planes, the image area that was “1” in the continuous three-dimensional area is connected between the planes. It will be the same label number. As a result, the image areas are connected at least between the planes, compared to a processing method that performs independent labeling within each plane and then connects the planes to connect the image areas included in the same area as a three-dimensional area. The labeling process in this embodiment can be performed at a high speed by the processing time for checking the above. This is also due to the fact that the connection relationship of the image areas can be referred to three-dimensionally by two-dimensional scanning twice including re-labeling.
[0038]
Note that when the uppermost plane (z = 0) plane 801a is the target plane, there is an upper plane, so that all data constituting the upper plane is treated as 0 and the process proceeds. The same processing is performed on the bottom surface.
[0039]
FIG. 9 shows a flowchart of the above three-dimensional labeling process.
[0040]
First, the label number variable i is initialized to 1 (step S901). Then, each pixel in the plane is three-dimensionally scanned to search for a pixel having a pixel value of 1 (step S902). When a pixel having a pixel value of 1 is found first (step S903), the label number of that pixel is set to i, that is, 1 (step S904). Thereafter, a pixel having a pixel value of 1 is searched. When the pixel value of the target pixel is 0, the label number of the target pixel is set to 0 (step S915).
[0041]
When a pixel with a pixel value of 1 (a pixel with a pixel of interest of 1) is found (step S905), a pixel with a label number is searched for in the neighborhood mask using the neighborhood mask shown in FIG. (Step S906). As a result of the search in step S906, when a plurality of pixels (here, for example, three are assumed and the label numbers are j, k, l, and j <k <l) are found, the process proceeds to step S907, where j, k , L, which is the smallest label number, is set as the label number of the pixel of interest (step S907). Also, label connection information indicating that the pixels with label numbers j, k, and l are three-dimensionally connected is generated (step S908).
[0042]
On the other hand, if a single pixel (label number j) is found as a result of the search in step S906, the process proceeds to step S909, and this label number j is set as the label number of the target pixel (step S909). If the pixel values (other than the target pixel) in the neighborhood mask are all 0 as a result of the search in step S906, the process proceeds to step S910, and the largest label number assigned so far (i) is set. The number obtained by adding 1 (i + 1) is set as the label number of the target pixel (step S910).
[0043]
Then, three-dimensional scanning is performed again (step S911). If it is determined in step S912 that scanning has not been performed for all pixels, the process proceeds to step S905, and the above-described process is repeated. On the other hand, when all the pixels in the plane have been scanned, the process is repeated until all the planes in the three-dimensional image have been scanned (step S913). Thereafter, re-labeling processing is performed based on the three-dimensional connection information found during scanning (step S914). Specifically, based on the above connection information, each image area is connected within each plane, and the same label number is assigned to each connected image area.
[0044]
In the above example, the binarization process is directly performed on the three-dimensional image, and then the three-dimensional labeling process is performed. First, a three-dimensional spatial filter (such as a low-pass filter or an intermediate value filter) is applied to the three-dimensional image. ) To remove the 3D image noise, and if necessary, perform the 3D spatial filtering to emphasize the needle, and then perform the labeling process to obtain the labeling result with better accuracy. .
[0045]
As a result of the labeling process described above, for example, in the three-dimensional image 201 shown in FIG. 2, different labels are assigned to the region of the needle image 202 and the other noise region. However, it is generally not possible at this point to determine whether the labeled area is a needle image. Therefore, next, a process for determining whether or not the obtained region is a needle image will be described.
[0046]
A needle image included in the three-dimensional image is roughly considered to be an image of an ellipsoid or a cuboid. By utilizing this, the candidate area estimated as the needle obtained by the above-described three-dimensional labeling process is regarded as a three-dimensional area of an elliptical sphere in the present embodiment, and its feature parameter is extracted, and this image is extracted. It is determined whether or not it is a needle.
[0047]
FIG. 5A shows a region estimated as a needle and an ellipsoid approximating this region. An area 501 is estimated as a needle, and an ellipsoid 502 approximates the area 501. As a characteristic parameter indicating this ellipse, a secondary moment around the center of gravity is obtained, and then the principal axis direction and three diameters L1, L2, and L3 are obtained as shown in FIG. 5B. Actually, the length is obtained as the number of pixels. Then, it is determined whether the values of L1, L2, and L3 and the ratio of Li / Lj (i, j = 1, 2, 3) satisfy a predetermined standard. If it is a needle, according to FIG. 5, L1 and L3 are small values, L2 is a large value,
L1 / L3 ≒ 1
L1 / L2 << 1
L3 / L2 << 1
Should be. In addition, the average CT value, circularity, sphericity, etc. of this ellipse may be obtained to determine whether or not they satisfy a predetermined standard of being a needle. From these determinations, it is determined whether or not the region estimated as a needle (image 501 in FIG. 5A) is a needle image. As a result of this determination, the label number is set to “0” for the image area determined not to be a needle image and is dropped from the needle candidates. Through the above processing, the three-dimensional region of the needle in the three-dimensional image can be specified.
[0048]
In addition, when the labeled three-dimensional image is decomposed into each plane, the plane including the needle region or the tip of the needle can be specified by referring to the label. Some of the planes (for example, three in FIG. 3B) are displayed on the display screen of the CRT 61. For example, as shown in FIG. When displaying a line tomographic image, it is possible to easily find a screen including a needle by specifying a plane including a needle region and changing the color of the frame of the specified screen. Note that the three images shown in FIG. 3B may be displayed on the display screen of one CRT 61, and when the CRT 61 is composed of a plurality of CRTs, each of the images is displayed on the display screen of each CRT. May be displayed.
[0049]
FIG. 7 shows a display example on the display screen of the CRT 61 that makes it easy to see the screen on which the needle image is displayed. Reference numerals 701, 702, and 703 denote screens for displaying images from the respective detector groups. In the example shown in FIG. 3B, images obtained from the detector groups A, B, and C are displayed. It is a screen. In the figure, reference numeral 705 denotes a needle image. By changing the color of the frame 702a of the screen 702 including this image, the operator can easily recognize that the needle image is displayed on the screen 702.
[0050]
Further, in order to obtain the tip of the needle in the three-dimensional image, an image is generated by thinning the needle image in the three-dimensional image using, for example, a three-dimensional logic filter described later. Then, end point detection is performed on the image of the needle subjected to the thinning process. Specifically, the end point detection process selects an end point candidate detected by the end point detection three-dimensional logic filter that substantially matches the vector in the principal axis direction when the ellipsoid is approximated.
[0051]
As a result, since the tip of the needle in the three-dimensional image can be specified, the plane on which the tip of the needle exists can be specified. Then, the value of the pixel existing at the position of the tip of the needle (or the vicinity thereof) in the plane is changed to a color (for example, red or yellow) that is easy for the operator to recognize (see pointer 1101 in FIG. 11). As a result, the operator can easily recognize the position of the tip of the needle instantaneously by referring to the display screen of the CRT 61 provided in the vicinity, and can concentrate on the puncturing operation. Note that the above-described process of changing the color of the frame may be performed only on the frame of the screen displaying the tip of the needle.
[0052]
Next, the above three-dimensional logic filter will be briefly described. The three-dimensional logic filter used for the thinning process in this embodiment uses data of the pixel of interest in the three-dimensional image and pixels near 26 of the pixel of interest, and data when “1” should be output as a result of the thinning process. A condition part for logically combining patterns, a value “1” corresponding to the thinning process result for the data pattern described in the condition part, and a thinning process result for a data pattern other than the data pattern described in the condition part And an output unit that outputs a value “0” corresponding to.
[0053]
FIG. 12 shows a flowchart of the above process. When a three-dimensional image is input (step S1201), the above-described three-dimensional spatial filtering processing (such as a low-pass filter and an intermediate value filter) is performed on the input three-dimensional image (step S1202). The processing in step S1202 may be omitted as necessary. Next, a three-dimensional labeling process is performed on the three-dimensional image (filtered as necessary) (step S1203). The details of the three-dimensional labeling process in step S1203 are as described above.
[0054]
Next, an ellipse approximating the three-dimensional region estimated as a needle is obtained, and the principal axis direction of the ellipse and the ratio of the three diameters, the respective diameters, the ellipticity, the sphericity, etc. of the ellipse are obtained (step S1204). Then, it is determined whether the result of the obtained characteristic parameter satisfies a predetermined condition (step S1205). If it is determined that the result is not a needle, the process proceeds to step S1206, and the label number is set to 0 for this area. Thus, it is removed from the needle candidates (step S1206). After the above processing is completed for all label numbers (steps S1207 and S1211), the process proceeds to step S1208, and thinning processing is performed on the area of the label number determined to be a needle (step S1208). After that, end point processing is also performed. Next, on the screen displayed on the screen (three in FIG. 3B and two in FIG. 3C), the screen on which the needle is displayed is specified (step S1209). Then, the color of the frame of the specified screen is changed. Further, the color of the pixel at the tip position of the needle (or a position in the vicinity thereof) is changed (step S1210).
[0055]
When changing the frame color of the screen on which the needle tip is displayed, the screen on which the needle tip is displayed is specified in step S1209, and the color of the frame of the screen specified in step S1210 is changed.
[0056]
In this embodiment, the color of the screen frame displaying the needle image or the frame of the screen displaying the needle tip is changed so that the operator can easily recognize it. For example, the frame may blink in a predetermined color, or a pointer pointing near the tip of the needle may be displayed near the tip of the needle.
[0057]
FIG. 13 shows a flowchart of overall processing of the gantry apparatus 100 and the operation console 200.
[0058]
First, a scan plan is input on the operation console 200 using the keyboard 57 and the mouse 58 (step S1351). When the scan plan is completely input to the operation console 200 (step S1352), the input scan plan is transmitted to the gantry apparatus 100 (step S1353). When the gantry apparatus 100 receives a scan plan from the operation console 200 (step S1301), it prepares for scanning based on the received scan plan (step S1302). Then, the gantry apparatus 100 performs a scan based on the received scan plan (step S1303). Then, the scanning result (projection data) is transmitted to the operation console 200 (step S1304). The timing for transmitting the projection data to the operation console 200 follows a known method.
[0059]
The operation console 200 receives the projection data (step S1354), and reconstructs an X-ray tomogram based on the received projection data by a known technique (step S1355). Then, a tomographic image is displayed on a screen corresponding to each detector group when each column of the X-ray detection unit 8 is divided into a plurality of detector groups (step S1356). This step includes a process of combining projection data from a plurality of detectors and displaying the result.
[0060]
In step S1357, the screen on which the needle image or the tip of the needle is displayed is specified, and the frame color of the specified screen is changed. In this step, the color of the pixel at or near the position of the needle is changed. Details of the processing in this step are as shown in FIG.
[0061]
The processes from the above scan (step S1302) to the needle tip display (step S1357) are repeated as long as the scan continues.
[0062]
In the present embodiment, both the color change processing of the frame of the screen on which the needle image or the needle tip is displayed and the processing of changing the value of the pixel at the needle tip position or the vicinity thereof are performed. However, only one of the processes may be executed.
[0063]
[Second Embodiment]
In this embodiment, in addition to the method for detecting the position of the needle tip in the three-dimensional image described in the first embodiment, a method for checking the position of the detected needle tip will be described.
[0064]
In general, artifacts (false images) are likely to occur at the tip of the needle. FIG. 14 shows a relationship between an image estimated as a needle and an artifact. Reference numeral 1401 denotes an image estimated as a needle, and reference numeral 1402 denotes an artifact. Therefore, in a three-dimensional image (which may be a two-dimensional plane), the artifact 1402 is subjected to polar coordinate conversion or Hough conversion with the tip of the needle as the center. The result is as shown in FIG. 15. A profile added in a certain diameter range or radial direction is obtained, and if the standard deviation value (variation in the frequency in the θ direction) is large, it is determined that the tip of the needle is present. Based on the determination result, it is possible to determine whether or not the artifact is unique to the needle tip, and at the same time, it is possible to specify whether or not the tip of the needle is based on the artifact.
[0065]
[Third Embodiment]
Moreover, if the method for specifying the position of the tip of the needle in the X-ray tomogram described in the above embodiment is used, the inspection target (region of interest) such as a lesion in the X-ray tomogram and the tip of the needle A message corresponding to the positional relationship can be notified to the operator. Since the needle puncture is performed on the inspection target, for example, the position of the tip of the needle relative to the inspection target is located such that the current needle position is close to or far from the inspection target. It is important to notify the operator of whether or not.
[0066]
Hereinafter, a case where the operator is notified of a message according to the positional relationship between the needle tip and the inspection target will be described. In this embodiment, this message is notified by voice. FIG. 16 is a block configuration diagram of the X-ray CT system of the present embodiment according to the present embodiment. The same parts as those in FIG. 1 are denoted by the same reference numerals, and the description thereof is omitted. A speaker 62 performs D / A conversion on sound data stored in the RAM 53 in accordance with an instruction from the CPU 51, and outputs the sound as sound.
[0067]
First, using the X-ray CT system shown in the figure, a scout scan for determining a range for performing a helical scan or an axial scan is performed. Here, the helical scan refers to a scan in which the scan is continuously performed while moving the scan position in the z-axis direction. An axial scan refers to a scan in which a scan at a next scan position is performed for all scan positions after a scan at one scan position is completed. The scout scan refers to a scan that scans the subject in the z-axis direction while fixing the position of the X-ray tube.
[0068]
Based on the two-dimensional image obtained by the scout scan, the operator determines a range for performing the helical scan or the axial scan, and further performs a helical or axial scan within the determined range. Then, the operator designates an ROI that is an area including the inspection object from a plurality of X-ray tomographic images obtained as a result of the helical or axial scan using the keyboard 57 and the mouse 58.
[0069]
FIG. 18 shows a state in which the ROI is set for the inspection object. In the figure, 1800 is an X-ray tomographic image, 1801 is an inspection object portion, and 1802 is an ROI. In the figure, a rectangular area including the inspection target portion 1801 is set as the ROI. The ROI shape is not limited to a rectangle. Note that there may be one or more X-ray tomographic images specifying the ROI.
[0070]
Since the position of the tip of the needle in the X-ray tomogram can be obtained as described in the above embodiment, the position of the needle tip and the position of the ROI (for example, the position of the center of gravity of the ROI) in the obtained X-ray tomogram. The distance d is obtained. A message corresponding to the obtained distance d is output from the speaker 62. An example of a table indicating the relationship between the distance d and the message is shown in FIG.
[0071]
If the distance d is 0 ≦ d <d1, the CPU 51 reads out the message data “ms1.dat” stored in the HDD 54 to the RAM 53 and outputs a sound based on this data to the speaker 62. The CPU 51 controls the speaker 62 so that it is output from. When the distance d is d1 ≦ d <d2, the message data “ms2.dat” stored in the HDD 54 is read into the RAM 53, and the CPU 51 causes the speaker 62 to output a sound based on this data from the speaker 62. Control. The message is output every certain time (for example, every 5 seconds).
[0072]
Since the smaller the value of the distance d is, the closer the tip of the needle is to the ROI (closer to the inspection object), “ms2.dat” is sound data such as “still far from the ROI”, For example, “ms1.dat” is data of a sound “I entered ROI”, so that a message is set so as to notify the operator that the tip of the needle is closer to the ROI as the distance d is smaller. The above d1 may be dynamically obtained so that the tip of the needle is within the ROI when the distance d is 0 ≦ d <d1. The data in the table and the sound data of each message are stored in the HDD 54 and loaded into the RAM 53 as necessary.
[0073]
When ROI is set for a plurality of X-ray tomographic images, processing for obtaining the distance d in the X-ray tomographic image in which the tip of the needle exists, and processing for outputting a message based on the obtained distance d. Do.
[0074]
Note that the content of the message to be notified to the operator is not limited to merely indicating that the tip of the needle is far from or close to the ROI position. It may indicate whether the tip of the head is on the top, bottom, on the right, or on the left. Further, when the tip of the needle is deviated from the position of the ROI, it may be indicated in which direction the correction should be made. In that case, it is possible to determine the plane on which the tip of the needle exists, and notify the positional relationship by comparing the existing plane (that is, the position of the tip of the needle) with the position of the ROI. I can do it. Of course, it is necessary to store the contents of the message corresponding to the positional relationship in advance in the HDD 54 as a table.
[0075]
Further, the content of the message is not limited to the utterance of a word, but other monotonous sounds (for example, “beep” sound) may be repeatedly output, and the repetition period may be changed according to the distance d. (For example, the smaller the distance d, the shorter the repetition period).
[0076]
By performing the above processing, the operator can puncture the needle while listening to the above message while grasping the position of the tip of the needle relative to the ROI. A needle can be punctured to the area.
[0077]
[Fourth Embodiment]
The method for obtaining the tip position of the needle used in the third embodiment is not limited to the method described in the first and second embodiments, and a simpler method may be used. That is, the three-dimensional image is binarized and the binarized result is labeled. After the labeling process, the method described in the first embodiment is used.
[0078]
[Other Embodiments]
Another object of the present invention is to supply a storage medium (or recording medium) in which a program code of software that realizes the functions of the above-described embodiments is recorded to a system or apparatus, and to perform a computer (or CPU or CPU) of the system or apparatus. (MPU) can also be realized by reading and executing the program code stored in the storage medium. In this case, the program code itself read from the storage medium realizes the functions of the above-described embodiments, and the storage medium storing the program code constitutes the present invention. Further, by executing the program code read out by the computer (operation console), not only the functions of the above-described embodiments are realized, but also an operating system running on the computer based on the instruction of the program code ( OS) etc. perform part or all of the actual processing, and the functions of the above-described embodiments are realized by the processing.
[0079]
When the present invention is applied to the above-mentioned storage medium, the storage medium includes a program code corresponding to the above-described (a part or all of the flowchart shown in FIG. 9 and / or FIG. 12 and / or FIG. 13). Will be stored.
[0080]
As a storage medium for storing such a program code, for example, a floppy (registered trademark) disk, a hard disk, an optical disk, a magneto-optical disk, a CD-ROM, a magnetic tape, a nonvolatile memory card, a ROM, or the like can be used. Furthermore, it may be downloaded via a medium called a network (for example, the Internet).
[0081]
【The invention's effect】
As described above, according to the present invention, the operator can be notified of the screen on which the tip of the needle is displayed.
[Brief description of the drawings]
FIG. 1 is a block configuration diagram of an X-ray CT system according to a first embodiment of the present invention.
FIG. 2 is a diagram showing a three-dimensional image composed of a plurality of X-ray tomographic images of a subject obtained by the X-ray CT system shown in FIG.
FIG. 3 is a diagram showing a display example of an X-ray tomographic image obtained from each detector.
FIG. 4 is a diagram illustrating a configuration of a three-dimensional labeling process.
FIG. 5 is a diagram illustrating an image estimated as a needle and an ellipsoid that includes the image.
FIG. 6 is a diagram showing a configuration of a neighborhood mask.
FIG. 7 is a diagram showing a display example in which a screen on which a needle is displayed, which is displayed on the display screen of the CRT 61, is easy to see.
FIG. 8 is a diagram showing a plane and a neighborhood mask.
FIG. 9 is a flowchart of a three-dimensional labeling process.
FIG. 10 is a diagram illustrating connection information.
FIG. 11 is a diagram showing a screen in which the position of the tip of a needle or the color of a pixel in the vicinity thereof is changed.
FIG. 12 is a flowchart of processing for changing the color of a frame of a screen on which a needle is displayed, or changing the color of a pixel at a position ahead of the needle (or a position in the vicinity thereof).
13 is a flowchart of overall processing of the gantry apparatus 100 and the operation console 200. FIG.
FIG. 14 is a diagram illustrating a relationship between an area estimated as a needle and an artifact.
FIG. 15 is a diagram showing a profile obtained by adding a result of a polar coordinate conversion or a Hough conversion with respect to the tip of a needle in a three-dimensional image and a certain diameter range or radial direction.
FIG. 16 is a block configuration diagram of an X-ray CT system of the present embodiment according to the third embodiment of the present invention.
FIG. 17 is a diagram illustrating an example of a table indicating a relationship between a distance d and a message.
FIG. 18 is a diagram illustrating a state in which an ROI is set for an inspection target.

Claims (20)

An image display device comprising a plurality of display units for displaying X-ray tomograms obtained by performing a fluoro scan on a subject punctured with a needle,
Detection means for detecting an end point of the needle from an X-ray tomographic image including an image of the needle;
Check means for checking whether or not the end point of the needle detected by the detection means is the end point of the needle based on the presence or absence of an artifact peculiar to the needle tip in the vicinity of the end point of the needle detected by the detection means;
An image display device comprising: a display unit that identifies a display unit on which the end point of the needle is displayed in the plurality of display units and notifies the display unit. An image display device comprising a plurality of display units for displaying X-ray tomograms obtained by performing a fluoro scan on a subject punctured with a needle,
An X-ray tomographic image including the needle image, which is a set of X-ray tomographic images, binarized to perform a three-dimensional labeling process and extract a three-dimensional continuous region. And a region estimated as a three-dimensional continuous region of the needle from the three-dimensional image according to the result of the means and the three-dimensional labeling process, and based on ellipsoidal approximation information or rectangular parallelepiped approximation information including the region Determining means for determining a needle image in each X-ray tomographic image;
Detecting means for detecting an end point of the needle from the image determined as the needle image by the determining means;
Check means for checking whether the end point of the needle detected by the detection means is the end point of the needle based on the presence or absence of an artifact peculiar to the needle tip in the vicinity of the end point of the needle detected by the detection means;
An image display device comprising: a display unit that identifies a display unit on which the end point of the needle is displayed in the plurality of display units and notifies the display unit.  The image display apparatus according to claim 2, further comprising a three-dimensional spatial filtering processing unit that performs a three-dimensional spatial filtering process for removing image noise on the three-dimensional image.  The image display apparatus according to claim 3, wherein the three-dimensional spatial filtering processing means includes a low-pass filter, an intermediate value filter, a maximum value filter, and a minimum value filter as filters used for the filtering process. When the three-dimensional continuous region extraction unit performs labeling on a target pixel included in a target plane, the pixel group in the vicinity of the target pixel in the plane including the target pixel and a plane adjacent to the plane are displayed in the vicinity. Reference is made using a mask, and when the value of the target pixel is 1 and the number of pixels labeled in the neighborhood mask is plural, the smallest label among the label numbers of the plurality of pixels When the number is the label number of the pixel of interest, the value of the pixel of interest is 1, and the number of pixels labeled in the neighborhood mask is one, the label number of the pixel of interest is The number obtained by adding 1 to the largest label number already used when the value of the pixel of interest is 1 and the pixel with the label number in the neighborhood mask does not exist as the label number The image display apparatus according to claim 2 or 3, characterized in that the label number of the pixel of interest.  The three-dimensional continuous region extracting means generates connection information indicating that the plurality of pixels are connected when the number of pixels labeled in the neighborhood mask is plural. The image display device according to claim 5.  The image display apparatus according to claim 6, further comprising a connection unit that connects the plurality of pixels based on the connection information and sets the label numbers of the plurality of pixels to the same number.  The neighboring mask has a shape extending over an X-ray tomographic image including the pixel of interest and an X-ray tomographic image adjacent to the X-ray tomographic image, and is a three-dimensional neighborhood mask that can refer to a pixel group near the pixel of interest. The image display device according to claim 5, wherein the image display device is an image display device.  3. The determination unit according to claim 2, wherein the determination unit determines whether a region estimated as a three-dimensional continuous region of the needle is a needle based on a major axis and a minor axis of the ellipsoid approximate information. Image display device.  The determination means obtains at least one of the major axis, minor axis, ratio of minor axis to major axis, circularity, sphericity, and using the obtained result, a region estimated as a three-dimensional continuous region of the needle is obtained. The image display device according to claim 9, wherein it is determined whether or not the region is a needle region.  3. The image display device according to claim 2, wherein for the three-dimensional continuous area determined to be a needle by the determination means, the corresponding label number is converted into a display color of the needle.  The image display apparatus according to claim 2, wherein the detection unit detects an end point of the needle after performing thinning processing on the image determined as the needle image by the determination unit. The notification means, the image display apparatus according to any one of claims 1 to 12, characterized in that to change the color of the frame of the display unit end point of the needle detected by the detection means is displayed . The said notification means blinks the color of the flame | frame of the display part in which the end point of the needle | hook detected by the said detection means is displayed by predetermined color, It is any one of Claim 1 thru | or 12 characterized by the above-mentioned. Image display device. 2. The notification unit further changes the position of the end point of the needle or the color of a pixel in the vicinity thereof on a display unit on which the end point of the needle detected by the detection unit is displayed. 15. The image display device according to any one of 1 to 14 . The check means performs a polar coordinate conversion or a Hough conversion on the needle end point candidates of the X-ray tomogram based on the standard deviation of the CT values around the needle end point candidates for the presence or absence of unique artifacts in the needle tip. The image display device according to claim 1, wherein the determination is made . Further, it claims 1 to 16, characterized in that it comprises a voice notification unit for notifying a voice message corresponding to the positional relationship between the end points of the detected needle by the attention area and the detection means provided on the X-ray tomographic image The image display device according to any one of the above. An X-ray CT apparatus comprising the image display apparatus according to claim 1. A program for causing a computer to function as the image display device according to any one of claims 1 to 17 . A computer-readable storage medium storing the program according to claim 19 .

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