JP6123695B2 - X-ray equipment - Google Patents

Description

  The present invention relates to an X-ray imaging apparatus effective for interventional treatment or the like that captures an image of a region including a device inserted into a body of a subject, and in particular, emphasizes the device in the image and emphasizes the image. It is related with the technology to display.

  In the medical field, coronary intervention treatment (PCI: Percutaneous Coronary Intervention) is performed on patients with myocardial infarction or angina. In the coronary intervention treatment, a catheter having a wire inside is inserted into a blood vessel of a subject, and the catheter reaches the coronary artery of the heart via the blood vessel to perform the treatment. The position of the catheter inserted into the body of the subject is confirmed at any time by continuously taking X-ray images.

  A stent is used as a device used for coronary intervention treatment. A stent is a cylindrical medical device made of metal or the like, and is placed in a stenotic portion of a coronary artery that is expanded using a balloon to hold a blood vessel from a lumen. By placing the stent in the coronary artery, the therapeutic effect of the catheter is improved. In recent years, a plurality of stents are often placed in order to improve the therapeutic effect. In this case, if a gap is generated between a previously placed stent and a newly placed stent, the blood vessel may be narrowed in the gap. Therefore, confirming the position of the stent is extremely important in treatment.

  Conventionally, in order to improve the visibility of a stent inserted into the body of a subject, X-ray images are continuously captured using a stent having a feature point such as a marker. Then, the captured X-ray images for a plurality of frames are superimposed. When superimposing, the stent can be highlighted by superimposing the feature points provided on the stent as a reference (see, for example, Patent Document 1).

  A configuration of an X-ray imaging apparatus according to a conventional example will be described with reference to the drawings. As shown in FIG. 9, the conventional X-ray imaging apparatus 100 includes a top plate 101, an X-ray tube 103, an X-ray detector 105, an image forming unit 107, an integrating unit 109, a cut-out display unit 111, and the like. It has. The image forming unit 107 is provided at the subsequent stage of the X-ray detector 105, and the integrating unit 109 is provided at the subsequent stage of the image forming unit 107. A cut-out display unit 111 is provided after the integrating unit 109.

  The top 101 places a subject M in a horizontal posture. The X-ray tube 103 irradiates the subject M with X-rays. The X-ray tube 103 and the X-ray detector 105 are disposed to face each other with the top plate 101 interposed therebetween. The X-ray detector 105 detects X-rays that are transmitted through the subject M from the X-ray tube 103, converts the detected X-rays into electrical signals, and outputs the signals as X-ray detection signals. As an example of the X-ray detector 105, a flat panel detector (FPD: Flat Panel Detector) is used.

  FIG. 10 is a schematic diagram showing a configuration of a catheter 113 used for PCI according to a conventional example. The catheter 113 includes a wire 115 inside. A stent 117 is provided at the distal end of the wire 115. The stent 117 includes two markers 119. One of the markers 119 is provided on the distal end side of the stent 117, and the other of the markers 119 is provided on the proximal end side of the stent 117.

  The stent 117 is a grid-like cylindrical body made of a metal wire such as stainless steel. The marker 119 is made of a radiopaque material and clearly indicates the position of the stent 117 in the X-ray image.

  Next, the operation of the conventional X-ray imaging apparatus 100 will be described with reference to the drawings. In performing PCI, the catheter 113 is inserted into the blood vessel of the subject. 11 shows a state where the catheter 113 is inserted into the blood vessel 121 having the branch pipe 123 and the branch pipe 125, and the stent 117 is inserted into the branch pipe 123 together with the wire 115.

  The catheter 113 inserted into the blood vessel of the subject M is continuously imaged by the X-ray imaging apparatus 100. That is, X-rays are intermittently emitted from the X-ray tube 103 to the subject M. X-rays transmitted through the subject M are detected by the X-ray detector 105. The detected X-ray is converted into an electric signal and output to the image forming unit 107 as an X-ray detection signal.

  The image forming unit 107 intermittently forms an X-ray image 127 on which the catheter 113 and the stent 117 are projected based on the output X-ray detection signal. Each of the X-ray images 127 formed in the image forming unit 107 is transmitted to the integrating unit 109.

  The accumulating unit 109 superimposes a plurality of newly acquired X-ray images 127 to highlight the real-time image of the stent 117. In FIG. 12A, the newest X-ray image 127 transmitted from the integrating unit 109 is an X-ray image 127a, and the X-ray image 127a is followed by the newest X-ray image 127, and is indicated by reference numerals 127b to 127e. .

  The positions of the catheter 113 and the stent 117 that appear in each of the X-ray images 127a to 127e differ depending on the pulse and breathing of the subject M. Therefore, the integrating unit 109 superimposes the X-ray images 127a to 127e using each of the markers 119 as a reference, and acquires a superimposed image 129. The acquired superimposed image 129 is transmitted to the cutout display unit 111.

  The cutout display unit 111 cuts out the image of the stent 117 displayed on the superimposed image 129 and creates a cutout image 130. Then, the cutout display unit 111 rotates the cutout image 130 in an appropriate direction to enlarge it, and forms an enlarged image 131. Then, as shown in FIG. 12B, the cutout display unit 111 displays the formed enlarged image 131 as a combined image 133 together with the X-ray image 127a.

  In the enlarged image 131, the image of the stent 117 projected on each of the X-ray images 127a to 127e is superimposed on the basis of the marker 119, and further enlarged and cut out. Therefore, the image of the stent 117 displayed on the enlarged image 131 is excellent in visibility. The X-ray image 127a displays a real-time image of the stent 117. Therefore, the operator can confirm the real-time image of the stent 117 in a more favorable state by performing PCI while confirming the combined image 133.

JP 2012-81136 A

However, the conventional example having such a configuration has the following problems.
That is, in the conventional apparatus, the cutout display unit 111 cannot distinguish between the two markers 119, and thus forms the enlarged image 131 without considering the direction of the stent 117. Therefore, in the combined image 133, there is a concern that the positions of the distal end portion and the proximal end portion of the stent 117 are suddenly switched during the PCI, and the visibility of the stent 117 is lowered.

  Here, a specific example of the problem will be described with reference to FIG. First, when the catheter 113 is in the position shown in FIG. 13A inside the blood vessel 121, the straight line connecting the two markers 119 is a right shoulder. In the enlarged image 131, the two markers 119 are displayed so as to be positioned above and below the image. Therefore, the cutout image 130 cut out by the cutout display unit 111 is rotated clockwise to form an enlarged image 131. Therefore, the distal end side of the stent 117 is displayed below the enlarged image 131.

  On the other hand, when the catheter 113 advances inside the blood vessel 121 and the catheter 113 moves to a position as shown in FIG. 13B, the straight line connecting the two markers 119 rises to the right. Therefore, the cutout image 130 cut out by the cutout display unit 111 is rotated counterclockwise to form an enlarged image 131. Therefore, the distal end side of the stent 117 is displayed above the enlarged image 131.

  That is, while the catheter 113 is advanced from the position shown in FIG. 13A to the position shown in FIG. 13B, a phenomenon occurs in which the advancing direction of the stent 117 displayed in the enlarged image 131 is suddenly reversed. As a result, the operator 117 is confused by the stent 117 whose traveling direction is suddenly reversed in the combined image 133, and it is difficult to determine whether the catheter 113 should be advanced or returned.

  The present invention has been made in view of such circumstances, and provides an X-ray imaging apparatus capable of fixing the direction of a displayed device and improving the visibility of the device to an operator. For the purpose.

In order to achieve such an object, the present invention has the following configuration.
That is, in the X-ray imaging apparatus according to the present invention, an X-ray source that irradiates a subject with X-rays, an X-ray detection unit that detects X-rays transmitted through the subject, and the X-ray detection unit output X-ray image forming means for forming an X-ray image of a region including a device inserted into the body of the subject using a detection signal, and a plurality of X-rays having the same phase acquired by the X-ray image forming means An integration unit that forms an integrated image by superimposing images, an image cutout unit that cuts out an image of the device from an integrated image formed by the integration unit, and the device in the integrated image formed by the integration unit. Marker detecting means for detecting the position of the marker, and a device direction specifying hand for specifying the direction of the device displayed in the integrated image based on the position of the marker detected by the marker detecting means. And based on the direction of the device specified by the device direction specifying unit, the image of the device cut out by the image cutout unit is rotated so that the device faces a certain direction, and the rotated image of the device And an enlarged image forming means for forming an enlarged image obtained by enlarging the image.

  [Operation / Effect] According to the X-ray imaging apparatus of the present invention, the device direction specifying means specifies the direction of the device based on the position of the marker in the X-ray image detected by the marker detecting means. By specifying the direction of the device, the device is directed in a certain direction in the enlarged image formed by the enlarged image forming unit. Therefore, the visibility of the device displayed in the enlarged image can be improved. Therefore, when performing PCI using the X-ray imaging apparatus according to the present invention, the operator can appropriately grasp the traveling direction of the device and perform PCI safely.

  In the above-mentioned invention, a guide wire is provided at the tip, and further includes a catheter connected to the device via the wire, the device direction specifying means detects the guide wire and the wire, and the guide wire It is preferable that the direction of the device is specified by tracing the wire from and detecting the marker having the closest distance to the guide wire.

  [Operation and Effect] According to the X-ray imaging apparatus of the present invention, the device direction specifying means detects the guide wire and the wire, traces the wire from the guide wire, and detects the marker that is closest to the guide wire. . By tracing the wire from the guide wire, the marker on the guide wire side among the markers provided in the device can be specified even if the orientation of the device is reversed due to the shape of the blood vessel. As a result, the direction of the device can be suitably specified.

  Further, in the above-described invention, a guide wire is provided at a distal end, and further includes a catheter connected to the device via the wire, and the device direction specifying means detects the catheter and the wire, and the wire from the catheter It is preferable that the direction of the device is specified by detecting the marker having the shortest distance from the catheter by tracing.

  [Operation / Effect] According to the X-ray imaging apparatus of the present invention, the device direction specifying means detects the catheter and the wire, traces the wire from the catheter, and detects the marker closest to the catheter. By tracing the wire from the catheter, the marker on the catheter side can be identified among the markers provided on the device even if the orientation of the device is reversed due to the shape of the blood vessel. As a result, the direction of the device can be suitably specified.

  In the above-described invention, it is preferable that the device direction specifying unit specifies the direction of the device using a line extraction algorithm based on a region growing method.

  [Operation / Effect] According to the X-ray imaging apparatus of the present invention, the direction of the device is specified using a line extraction algorithm such as the region growing method. The region growing method is an image dividing method in which a reference point is set, a point adjacent to the reference point and having the same characteristics as the reference point is integrated with the reference point to grow the reference point. Therefore, even a thin region such as a wire can be specified as a reference point group in which a marker and a catheter are connected with a wire by integrating with a reference point. That is, the distance between the marker and the catheter or guide wire can be calculated by tracing the wire from each marker. Therefore, each marker provided on the device can be more appropriately distinguished, and the direction of the device can be specified more accurately.

  In the above-described invention, the image display unit further includes an image display unit that displays an image, and the image display unit includes the enlarged image formed by the enlarged image forming unit and the real-time X-ray formed by the X-ray image forming unit. It is preferable to display the image in parallel.

  [Operation / Effect] According to the X-ray imaging apparatus of the present invention, the image display means displays a real-time X-ray image in parallel with the enlarged image. Since the direction of the device displayed in the enlarged image is always constant, the visibility of the device displayed in the enlarged image is improved. Then, by displaying the real-time X-ray images in parallel, the operator can check the real-time image of the device at the same time. Therefore, the operator can confirm the images arranged in parallel, and can continue the operation more safely and can reach the target coronary artery.

  According to the X-ray imaging apparatus according to the present invention, the device direction specifying unit specifies the device direction based on the marker position in the X-ray image detected by the marker detection unit. By specifying the direction of the device, the device is directed in a certain direction in the enlarged image formed by the enlarged image forming unit. Therefore, the visibility of the device displayed in the enlarged image can be improved. Therefore, when performing PCI using the X-ray imaging apparatus according to the present invention, the operator can appropriately grasp the traveling direction of the device and perform PCI safely.

It is the schematic explaining the structure of the X-ray imaging apparatus which concerns on an Example. It is the schematic explaining the structure of the catheter which concerns on an Example. It is the schematic explaining the positional relationship in the blood vessel of the catheter which concerns on an Example. (A) is a flowchart explaining the process of the operation | movement which concerns on the X-ray imaging apparatus which concerns on an Example, (b) is a flowchart explaining in detail the process of step S3 which concerns on an Example. (A) is a figure explaining the basic operation | movement of the X-ray imaging apparatus which concerns on an Example, (b) is a figure explaining the image which the clipping display part concerning an Example displays. (A) is a flowchart explaining the process which concerns on a region growth method, (b) is a figure explaining the process of dividing a pixel into regions using a region growth method. In an Example, it is a figure explaining the method of specifying the direction of a stent. It is the schematic explaining the problem of the identification method of the marker in a prior art example. It is the schematic explaining the structure of the X-ray imaging apparatus which concerns on a prior art example. It is the schematic explaining the structure of the catheter which concerns on a prior art example. It is the schematic explaining the positional relationship in the blood vessel of the catheter which concerns on a prior art example. (A) is a figure explaining the basic operation | movement of the X-ray imaging apparatus which concerns on a prior art example, (b) is a figure explaining the image which the clipping display part concerning a prior art example displays. It is the schematic explaining the problem of the enlarged image which concerns on a prior art example. (A) has shown the figure before advancing of a catheter, (b) has shown the figure after advancing of a catheter.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a schematic diagram illustrating the configuration of the X-ray imaging apparatus according to the first embodiment.

<Description of overall configuration>
As shown in FIG. 1, the X-ray imaging apparatus 1 according to the embodiment includes a top plate 3, an X-ray tube 5, a collimator 7, an X-ray detector 9, an X-ray irradiation control unit 11, and a detection. A control unit 13, an image processing unit 14, and a main control unit 15. The top 3 places a subject M in a horizontal posture. The X-ray tube 5 irradiates the subject M with X-rays. The X-ray tube 5 corresponds to the X-ray source in the present invention.

  A collimator 7 is provided below the X-ray tube 5 to limit the X-rays emitted from the X-ray tube 5 to a cone shape that is a pyramid. The X-ray tube 5 and the X-ray detector 9 are disposed to face each other with the top plate 3 interposed therebetween. The X-ray detector 9 detects X-rays that are transmitted through the subject M from the X-ray tube 5, converts them into electrical signals, and outputs them as X-ray detection signals. In the embodiment, a flat panel detector (FPD) is used as the X-ray detector 9. The X-ray detector 9 corresponds to the X-ray detection means in the present invention.

  The X-ray irradiation control unit 11 is connected to the X-ray tube 5 and controls the X-ray dose irradiated from the X-ray tube 5, the timing for irradiating X-rays, and the like. The detector control unit 13 is connected to the X-ray detector 9 and controls the operation of reading the charge signal converted by the X-ray detector 9, that is, the X-ray detection signal.

  The image processing unit 14 includes an X-ray image forming unit 16, an integrating unit 17, an image clipping unit 19, a marker detecting unit 20, a stent direction specifying unit 21, and an enlarged image forming unit 22. The X-ray image forming unit 16 is provided at the subsequent stage of the X-ray detector 9 and forms an X-ray image based on the X-ray detection signal output from the X-ray detector 9. The accumulating unit 17 is provided in the subsequent stage of the X-ray image forming unit 16 and forms an overlapped image by superimposing the X-ray images formed by the X-ray image forming unit 16. The X-ray image forming unit 16 corresponds to the X-ray image forming unit in the present invention, and the integrating unit 17 corresponds to the integrating unit in the present invention. The superimposed image corresponds to the accumulated image in the present invention.

  The image cutout unit 19 is provided in the subsequent stage of the integration unit 17 and cuts out the stent displayed in the superimposed image and an image near the stent to form a cutout image. The marker detection unit 20 is provided after the integration unit 17 and detects a marker displayed on the superimposed image. The stent direction specifying unit 21 is provided in the subsequent stage of the marker detection unit 20 and specifies the direction of the stent shown in the superimposed image. The stent direction specifying unit 21 outputs information related to the stent direction to the enlarged image forming unit 22.

  The enlarged image forming unit 22 is provided at the subsequent stage of the image clipping unit 19, and the clipped image formed by the image clipping unit 19 is output to the enlarged image forming unit 22. Then, the enlarged image forming unit 22 rotates the cut image based on the information output from the stent direction specifying unit 21 so that the stent direction is constant. The X-ray imaging apparatus 1 further includes a monitor 23, and the enlarged image forming unit 22 enlarges the rotated clipped image to form an enlarged image, and transmits the enlarged image to the monitor 23. The monitor 23 displays the transmitted enlarged image.

  The X-ray irradiation control unit 11, the detector control unit 13, and the image processing unit 14 are comprehensively controlled by the main control unit 15. The image cutout unit 19 corresponds to the image cutout unit in the present invention, and the marker detection unit 20 corresponds to the marker detection unit in the present invention. The stent direction specifying unit 21 corresponds to a device direction specifying unit in the present invention, and the enlarged image forming unit 22 corresponds to an enlarged image forming unit in the present invention. Furthermore, the monitor 23 corresponds to the image display means in the present invention.

  FIG. 2 is a schematic diagram showing the configuration of a catheter system 24 used for coronary intervention treatment (PCI). The catheter system 24 includes a catheter 25, a wire 27, a guide wire 29, and a stent 31. The wire 27 is inserted into the catheter 25. A guide wire 29 is provided at the tip of the wire 27. The stent 31 is provided on the wire 27 that connects the catheter 25 and the guide wire 29. The stent 31 includes a plurality of markers 33. In the embodiment, the number of markers 33 is two, but the number of markers 33 may be increased as appropriate. Of the two markers 33, one marker 33 is provided on the distal end side of the stent 31, and the other marker 33 is provided on the proximal end side of the stent 31.

  The stent 31 is a lattice-shaped cylindrical body made of a metal wire such as stainless steel, and a balloon (not shown) is provided inside. In PCI, the stent 31 is placed in a narrowed portion of the coronary artery. Then, the deployed stent 31 is inflated with a balloon, and the inflated stent 31 is placed in the blood vessel, thereby expanding the coronary artery and maintaining the blood flow normally. Each of the markers 33 is made of a radiopaque material and clearly indicates the position of the stent 31 in the X-ray image. Note that examples of the material constituting the marker 33 include metals such as gold, platinum, and tantalum. The stent 31 corresponds to the device in the present invention.

<Description of operation>
Next, the operation of the X-ray imaging apparatus 1 according to the embodiment will be described. In the description, a process of performing PCI using the X-ray imaging apparatus 1 will be used as an example. The left figure of FIG. 4 is a flowchart explaining the operation | movement process of the X-ray imaging apparatus 1 which concerns on an Example. And the right figure of FIG. 4 is a flowchart explaining the process of step S4 based on an Example concretely.

Step S1 (catheter insertion)
In performing PCI, a small hole is first made in the base of the thigh of the subject M and the catheter 25 is inserted into the blood vessel. 3 shows a state in which the catheter 25 is inserted into the blood vessel 35 having the branch pipe 37 and the branch pipe 39, and the stent 31 is inserted into the branch pipe 37 together with the guide wire 29.

Step S2 (X-ray image capturing)
Then, after inserting the catheter 25 into the blood vessel of the subject M, X-ray images are continuously taken. That is, X-rays are intermittently emitted from the X-ray tube 5 to the subject M. X-rays transmitted through the subject M are detected by the X-ray detector 9. The detected X-ray is converted into an X-ray detection signal that is an electrical signal, and the converted X-ray detection signal is output to the X-ray image forming unit 16.

  Based on the output X-ray detection signal, the X-ray image forming unit 16 intermittently forms an X-ray image 41 on which the catheter 25 and the stent 31 are projected. In the embodiment, the X-ray image 41 is captured at a frame rate of about 15 to 30 FPS, for example. Each of the X-ray images 41 formed in the X-ray image forming unit 16 is transmitted to the integrating unit 17.

Step S3 (formation of superimposed image)
The accumulating unit 17 superimposes a plurality of newly acquired X-ray images 41 to highlight the real-time image of the stent 31. In the first embodiment, the number of sheets to be superimposed is five, but the number of sheets may be changed as appropriate. In the upper part of FIG. 5A, the newest X-ray image 41 transmitted from the X-ray image forming unit 16 is set as an X-ray image 41a, and the X-ray image 41a next to the X-ray image 41a is sequentially assigned with reference numerals 41b to 41e. Shall be shown. The blood vessel 35 including the branch pipe 37 and the branch pipe 39 shown in FIG. 5 is schematically shown by a thin line.

  The positions of the catheter 25 and the stent 31 that appear in each of the X-ray images 41a to 41e differ depending on the pulse and respiration of the subject M. Therefore, the accumulating unit 17 superimposes the X-ray images 41a to 41e using each of the markers 33 as a reference, and acquires a superimposed image 43 (lower left in FIG. 5A). The acquired superimposed image 43 is transmitted to each of the image cutout unit 19 and the marker detection unit 20.

Step S4 (identification of stent traveling direction)
The marker detection unit 20 detects each of the markers 33 displayed in the transmitted superimposed image 43 (step S4-1). Information relating to each of the detected markers 33 is transmitted from the marker detection unit 20 to the stent direction identification unit 21. The stent direction specifying unit 21 calculates the positional relationship between the marker 33 and the catheter 25, and the marker 33 and the guide wire 29 based on each of the detected markers 33 (step S4-2). As a method for calculating the positional relationship between each marker 33, catheter 25, and guide wire 29, a line extraction algorithm is used. In the embodiment, a region growing method (Region Growing) is used as a specific example.

  And the stent direction specific | specification part 21 specifies the marker 33 provided in the front end side of the stent 31 among the markers 33, and the marker 33 provided in the base end side of the stent 31 based on the calculated positional relationship. (Step S4-3). That is, among the markers 33 provided on the stent 31, the marker 33 identified as being located on the guide wire 29 side (the distal end side of the stent 31) is labeled as a marker 33a. Then, the marker 33 identified as being located on the catheter 25 side (the proximal end side of the stent 31) is labeled as a marker 33b. By labeling the marker 33a and the marker 33b, the traveling direction of the stent 31 can be specified.

  Here, a method for calculating the positional relationship using the region growth method will be specifically described. In the region growing method, when a pixel of interest as a reference point and a pixel adjacent to the pixel have the same characteristics, a process of integrating them into one region is sequentially executed. This is a method in which regions having the same characteristics are gradually grown by sequentially integrating, and finally the region of the entire image is divided.

  FIG. 6A is a flowchart of the region growth method. In FIG. 6B, the region growth method will be described by taking as an example a region in which the pixels A are arranged in a two-dimensional matrix of 5 rows × 5 columns. In addition, when each pixel A is referred to separately, the number of rows g and the number of columns h are added and described as a pixel A (g, h).

  In the area growth method, first, a reference point is set. In FIG. 6B, it is assumed that the pixel A (3, 3) is set as the initial reference point, and the pixel A integrated with the reference point is indicated by hatching (FIG. 6B upper left). ). Next, the pixel value of the pixel A adjacent to the reference point pixel A (3, 3) is confirmed. When the pixel value satisfies a predetermined condition, the adjacent pixel A is integrated into the reference point, and when the pixel value is not satisfied, the adjacent pixel A is not integrated into the reference point and left.

  In FIG. 6B, the pixel A that satisfies the pixel value is indicated by a symbol ◯, and the pixel A that does not satisfy the condition is indicated by a symbol X. Therefore, among the pixels A adjacent to the pixel A (3, 3), the pixel A (2, 3), the pixel A (3, 2), and the pixel A (3, 4) are integrated into the reference point, and the pixel A ( 4 and 3) are left unintegrated with the reference point (upper right in FIG. 6B).

  Then, the pixel value confirmation and the integration to the reference point are repeated until there are no adjacent unconfirmed pixels (lower left of FIG. 6B). As a result, all of the pixels A that are continuous with the original reference point pixel A (3, 3) and satisfy a predetermined condition are specified as areas indicated by diagonal lines (FIG. 6 (b) right). under).

  In the embodiment, in the X-ray image 41, image segmentation by the region growing method is performed in order to identify the region where the catheter system 24 is reflected. The catheter 25 and the like constituting the catheter system 24 are all made of a material having a lower X-ray transmittance than that of a blood vessel. Therefore, the detected marker 33 is set as a reference point. Then, image segmentation by the region growing method is executed as a condition for integrating the pixel value smaller than a certain value into the reference point. As a result, the catheter 25, the wire 27, the guide wire 29, and the stent 31 connected to the marker 33 are integrated with the marker 33 that is the reference point, and the region where the catheter system 24 is shown is specified.

  A reference point group that is continuously the longest line is extracted from the region in which the catheter system 24 is identified by image division. The extracted reference point group is hereinafter referred to as a reference point line B. By extracting the reference dotted line B, the image division by the region growing method is completed.

  Then, as shown in FIG. 7, the thickness of the reference dotted line B is calculated. The thickness of the reference dotted line B is calculated from the length of the vertical line of the reference dotted line B. In the catheter system 24, the thickness P of the wire 27 is configured to be thinner than the thickness Q of the marker 33. Further, the thickness R of the guide wire 29 is configured to be thicker than the thickness P of the wire 27. Therefore, when the wire 27 is traced from the marker 33 toward the guide wire 29, the thickness of the reference dotted line B changes from Q to P at the boundary between the marker 33 and the wire 27 and further exceeds the tip of the guide wire 29. And the thickness of the reference dotted line B becomes zero. Therefore, the marker 33 provided on the distal end side of the stent 31 is used as the marker 33a by following the wire 27 whose reference dotted line B is P from the position where the thickness of the reference dotted line B changes from R to 0. Can be identified.

  On the other hand, in the catheter system 24, the thickness S of the catheter 25 is configured to be thicker than the thickness Q of the marker 33. Therefore, when the wire 27 is traced from the marker 33 toward the catheter 25, the thickness of the reference dotted line B changes from Q to P at the boundary between the marker 33 and the wire 27. Then, the thickness of the reference dotted line B rapidly changes from P to S at the boundary between the wire 27 and the catheter 25, and the thickness S continues uniformly. Therefore, the marker 33 provided on the proximal end side of the stent 31 is marked with the marker 25 by tracing the wire 27 whose thickness of the reference dotted line B is P from the catheter 25 in which the thickness of the reference dotted line B is detected as S. It can be specified as 33b. Information about the identified marker 33 a and marker 33 b is transmitted from the stent direction identifying unit 21 to the enlarged image forming unit 22.

Step S5 (formation of enlarged image)
The image cutout unit 19 cuts out the image of the stent 31 and its surrounding area from the superimposed image 43 transmitted from the integration unit 17 to form a cutout image 44. The formed cut-out image 44 is transmitted to the enlarged image forming unit 22. The enlarged image forming unit 22 rotates the cutout image 44 based on the information transmitted from the stent direction specifying unit 21 (the lower center of FIG. 5A). Specifically, the stent 31 displayed in the cutout image 44 is rotated so that the marker 33a is positioned at the top of the image and the marker 33b is positioned at the bottom of the image. The enlarged image forming unit 22 enlarges the rotated cutout image 44 to form an enlarged image 45. Further, in order to increase the visibility of the stent 31, an arrow D indicating the traveling direction of the stent 31 is displayed on the enlarged image 45 (lower right in FIG. 5A).

Step S6 (display combined image)
The enlarged image forming unit 22 transmits the acquired enlarged image 45 to the monitor 23 as shown in FIG. In addition, the latest X-ray image 41 a is transmitted from the X-ray image forming unit 16 to the monitor 23. The monitor 23 forms the combined image 47 by juxtaposing the transmitted X-ray image 41a and the enlarged image 45 in parallel. The monitor 23 displays the formed combined image 47.

  In the enlarged image 45, the image of the stent 31 projected on each of the X-ray images 41a to 41e is overlaid on the basis of the marker 33, and further enlarged and cut out. Since the distal end side of the image of the stent 31 displayed in the enlarged image 45 is always displayed on the upper side, the operator can easily confirm the direction of the stent 31. Further, since the X-ray image 41 a is the latest X-ray image 41, a real-time image of the stent 31 with high visibility is displayed in the combined image 47.

  And after the process of step S6 is complete | finished, the process which concerns on step S2-S6 is repeated sequentially. By repeating the processes according to steps S2 to S6, the real-time image of the stent 31 with high visibility can be continuously displayed in the combined image 47. Therefore, by confirming the combined image 47, the operator can safely continue the PCI procedure and advance the catheter 25 to the target coronary artery.

Step S7 (stent placement)
The operator makes the catheter 25 reach the narrowed portion of the coronary artery while confirming the real-time image of the stent 31 displayed in the combined image 47. Then, the balloon provided inside the stent 31 is inflated. Since the stent 31 is expanded by the balloon, the narrowed coronary artery is expanded. By placing the swollen stent 31 in the blood vessel, the blood flow in the coronary artery is kept normal. After placing the stent 31, the catheter 25 is extracted from the subject M following the blood vessel, and the PCI ends.

<Effects of Configuration of Example>
As described above, according to the X-ray imaging apparatus according to the embodiment, it is possible to provide an X-ray imaging apparatus that fixes the direction of the displayed device and improves the visibility of the device to the operator. Hereinafter, the effect by the structure which concerns on an Example is demonstrated.

  In the X-ray imaging apparatus 100 according to the conventional example, each of the two markers 119 provided on the stent 117 cannot be distinguished. When the enlarged image 131 is formed from the superimposed image 129, the cutout display unit 111 displays the cutout image of the stent 117, one of the markers 119 is above the enlarged image 131 and the other of the markers 119 is below the enlarged image 131. Rotate to be located at At this time, the cutout display unit 111 is rotated in a direction in which an angle necessary for rotation is reduced. That is, when the straight line connecting the two markers 119 falls to the right regardless of the traveling direction of the stent 117, the cutout display unit 111 rotates the image of the stent 117 cut out from the superimposed image 129 clockwise to enlarge the image. 131 is formed.

  On the other hand, when the straight line connecting the two markers 119 in the superimposed image 129 rises to the right, the cutout display unit 111 rotates the image of the stent 117 cut out from the superimposed image 129 counterclockwise to form the enlarged image 131. To do. In the conventional example having such a configuration, as shown in FIG. 13, when the straight line connecting the two markers 119 changes from the right shoulder rise to the right shoulder fall, the distal end portion and the proximal end portion of the stent 117 in the enlarged image 131. The position of suddenly changes. That is, the traveling direction of the stent 117 displayed in the enlarged image 131 is suddenly reversed. As a result, it is difficult for the conventional X-ray imaging apparatus to grasp the proper traveling direction of the stent 117, and thus the operator of the catheter 113 cannot perform PCI safely.

  In order to fix the traveling direction of the stent 117 displayed in the enlarged image 131, in the X-ray image 127, a marker provided on the distal end side of the stent 117 (hereinafter referred to as a marker 119a for convenience), the stent 117 It is necessary to distinguish a marker (hereinafter referred to as a marker 119b for the sake of convenience) provided on the base end side. As a conventional example of the method of distinguishing the marker 119, there is a method of identifying the marker 119a and the marker 119b from the difference in linear distance from the catheter 113.

  However, the conventional method has the following problems. That is, as shown in FIG. 8A, when the catheter 113 is traveling inside a straight blood vessel, the marker 119b is closer to the catheter 113 than the marker 119a. On the other hand, as shown in FIG. 8B, when the catheter 113 is traveling inside a tortuous blood vessel, the marker 119b is closer to the catheter 113 in the X-ray image 127 than the marker 119a. Therefore, it is difficult to accurately distinguish the marker 119 based on the linear distance from the catheter 113 displayed on the X-ray image 127.

  Therefore, in the X-ray imaging apparatus according to the embodiment, it is possible to accurately distinguish the markers provided on the stent by using a line extraction algorithm using the region growing method as an example. The region growing method is an image dividing method in which a pixel of interest is set as a reference point, and when the pixel adjacent to the reference point satisfies a certain condition, it is integrated with the reference point to grow the reference point. Therefore, by using a marker as a reference point, it is possible to identify a reference point group in which a thin region such as a wire is integrated and the marker and the catheter are connected by a wire. Then, by tracing the wire from each marker and calculating the distance from a feature point such as a catheter, the two markers can be accurately distinguished.

  Then, by rotating the cutout image cut out from the superimposed image based on the information of the distinguished marker in an appropriate direction, the advancing direction of the stent displayed in the enlarged image can always be fixed. Furthermore, the visibility of the stent can be further improved by displaying an arrow indicating the advancing direction of the stent on the enlarged image. Therefore, by performing PCI using the X-ray imaging apparatus according to the present invention, the operator can grasp the proper traveling direction of the stent and execute PCI more safely.

  The present invention is not limited to the above embodiment, and can be modified as follows.

  (1) In each of the above-described embodiments, the marker 33a provided on the distal end side of the stent 31 and the marker 33b provided on the proximal end side of the stent 31 are specified from among the plurality of markers 33. Not limited to. That is, only the marker 33b may be specified from the positional relationship with the catheter 25. Alternatively, only the marker 33a may be specified from the positional relationship with the guide wire 29.

  (2) In each of the above-described embodiments, the image of the stent 31 is cut out from the superimposed image 43 and then rotated. After the rotation, the image is enlarged, but the present invention is not limited thereto. In other words, the order of X-ray image superposition, cut-out image formation, cut-out image rotation, and cut-out image enlargement may be appropriately changed.

DESCRIPTION OF SYMBOLS 1 ... X-ray imaging apparatus 5 ... X-ray tube (X-ray source)
9 ... X-ray detector (X-ray detection means)
16 ... X-ray image forming unit (X-ray image forming means)
17 ... Integration unit (integration means)
19 ... Image cutout unit (image cutout means)
21 ... Stent direction specifying part (device direction specifying means)
22: Enlarged image forming unit (enlarged image forming means)
23. Monitor (image display means)
25 ... Catheter 27 ... Wire 31 ... Stent (device)
33 ... Marker 41 ... X-ray image 43 ... Superposition image 45 ... Enlarged image 47 ... Combined image

Claims (5)

An X-ray source for irradiating the subject with X-rays;
X-ray detection means for detecting X-rays transmitted through the subject;
X-ray image forming means for forming an X-ray image of a region including a device inserted into the body of the subject using a detection signal output by the X-ray detection means;
Integrating means for superimposing a plurality of X-ray images of the same phase acquired by the X-ray image forming means to form an integrated image;
Image cutout means for cutting out the image of the device from the integrated image formed by the integration means;
Marker detecting means for detecting the position of a marker provided in the device in the integrated image formed by the integrating means;
Device direction specifying means for specifying the direction of the device displayed in the integrated image based on the position of the marker detected by the marker detecting means;
Based on the direction of the device specified by the device direction specifying means, the image of the device cut out by the image cutout means is rotated so that the device faces a certain direction, and the image of the rotated device is enlarged. An X-ray imaging apparatus, comprising: an enlarged image forming unit that forms an enlarged image that has been made to appear. The X-ray imaging apparatus according to claim 1,
A guide wire at the tip, further comprising a catheter connected to the device via the wire;
The device direction specifying unit detects the guide wire and the wire, traces the wire from the guide wire, and detects the marker having the closest distance to the guide wire, thereby specifying the direction of the device. apparatus. The X-ray imaging apparatus according to claim 1,
A guide wire at the tip, further comprising a catheter connected to the device via the wire;
The X-ray imaging apparatus, wherein the device direction specifying means detects the catheter and the wire, and traces the wire from the catheter to detect the marker having the closest distance to the catheter. The X-ray imaging apparatus according to any one of claims 1 to 3,
The device direction specifying unit is an X-ray imaging apparatus that specifies a direction of the device using a line extraction algorithm based on a region growing method. The X-ray imaging apparatus according to any one of claims 1 to 4,
It further comprises image display means for displaying an image,
The X-ray imaging apparatus, wherein the image display unit displays the enlarged image formed by the enlarged image forming unit and the real-time X-ray image formed by the X-ray image forming unit in parallel.

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