JP2012081136A - Stent and x-ray diagnostic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique to readily determine whether or not a plurality of stents made of an X-ray transmissive material are placed on top of another in a mutually piled-up state.SOLUTION: In one embodiment, the stent forms a tubular structure made of an X-ray transmissive material with an expandable diameter, while having clearances. A first marker made of an X-ray non-transmissive material is provided on one end side of the tubular structure, while a second marker made of the X-ray non-transmissive material and having dimensions larger than the first marker by 40 μm or more is provided on the other end side of the structure.

Description

  Embodiments described herein relate generally to a stent and an X-ray diagnostic apparatus.

  A stent is used to treat a disease caused by stenosis or occlusion of a blood vessel or other in-vivo lumen, expanding the stenosis or occlusion site and placing it there to maintain its lumen size. It is a medical device (see, for example, Patent Document 1 and Patent Document 2). Stents are used in angioplasty of the heart, carotid artery, and lower limb artery, and are an important medical device in the field of cardiovascular treatment in, for example, ischemic heart disease.

  The stent has a substantially tubular shape with both ends opened so that blood flowing into one end side flows out from the other end side. However, the stent is not a complete tube, and its side surface has, for example, a mesh shape. This is because the blood flows also to a large number of blood vessels branched from the blood vessels expanded by the stent. A stent is a coil made of a single linear metal or polymer material, a metal tube cut out and processed by a laser, a mesh-like one assembled by welding linear members with a laser, There are things made by weaving multiple linear metals.

  In the case of a stent formed of a metal material as described above, there are problems such as that a foreign substance called metal remains in the body permanently, and that magnetic resonance imaging diagnosis makes it difficult to perform magnetic resonance imaging diagnosis. For this reason, development of a bioabsorbable stent made of a material that has no problem in diagnosis by a magnetic resonance imaging apparatus and that is decomposed and absorbed by the living body in several years and disappears, for example. Examples of the material of the bioabsorbable stent include polymers such as poly-L-lactic acid (PLLA).

  In addition, stents can be classified into two types according to the expanded form. First, what expands itself by removing a member that suppresses expansion is called a self-expandable type. Secondly, what is expanded by a balloon mounted with a stent is called a balloon expandable type. The balloon expandable type is used with a balloon catheter in which an expandable member such as a balloon is attached near the tip.

  Specifically, the balloon portion of the balloon catheter is attached to the inside of the stent, and the guide wire is inserted to the treatment site in the body lumen of the patient while the guide wire is passed through the inside of the balloon catheter tube. Next, the tip of the balloon catheter to which the stent is attached is advanced along the guide wire to the treatment site in the body lumen. Next, by flowing a dedicated liquid into the balloon catheter tube, the pressure in the tube is increased to inflate the balloon at the treatment site. This expands the diameter of the stent at the treatment site. Then, the balloon is deflated by removing the liquid, and the balloon catheter is removed, whereby the stent is placed at the treatment site.

  If the stenosis site is long and one stent is not long enough, two doctors are needed, and the doctor then puts the second stent and performs the same work as the first. And pull out the balloon. In the case of a drug-coated stent, since the drug is applied to the stent surface, it is recommended that the two stents be placed in a slightly overlapping manner when the two stents are directly arranged. This is because if the two drug-coated stents are separated, the drug will not spread between them.

  Therefore, after placing the two drug-coated stents, the doctor confirms their placement state, that is, the overlapping state of the two stents with an X-ray diagnostic apparatus (see, for example, Patent Document 3). More specifically, metal has a high X-ray absorption rate and is X-ray opaque. Therefore, if a metal stent is used as the above two stents and these are placed in the patient's body and photographed with an X-ray diagnostic apparatus, the position of the metal stent and the like are projected darker than the surroundings in the X-ray image. Can be identified.

JP 2007-105268 A JP-A-2005-342105 JP 2006-130158 A

  On the other hand, the polymer has a very low X-ray absorption rate and is X-ray transparent. Therefore, even if a patient having a polymer stent in the body is photographed by an X-ray diagnostic apparatus, the polymer stent is projected brightly in an X-ray image in the same manner as the surrounding X-ray transparent human tissue, so that it can be identified. I can't. That is, in fluoroscopic treatment using an X-ray diagnostic apparatus, a bioabsorbable stent made of a polymer material cannot be confirmed on an X-ray image.

  Therefore, when placing two polymer stents of, for example, a drug-coated type in the above-described procedure and checking the overlapping state of the two stents, the doctor uses a small radiopaque marker attached to each stent to identify each stent. Will guess the position. However, in the conventional polymer stent, it is difficult to determine whether the two stents are separated or overlap each other.

  For this reason, as a stent formed of an X-ray transparent material such as a polymer, there has been a demand for a technique that makes it easy to determine whether a plurality of stents are overlapped or separated from each other. In addition, when a plurality of stents made of an X-ray transmissive material are indwelled, there is a technique for detecting the position of each stent on the X-ray diagnostic apparatus side without imposing a heavy operation burden on the user. It was requested.

  Further, in a stent for treating an aneurysm, a patch for blocking blood flow to the aneurysm is formed on a part of the stent. Such a stent has an asymmetric structure between the side with the patch and the side without the patch, while it is desirable to place the stent so that the side with the patch becomes the aneurysm side.

  Further, a branch-type stent is known as an indwelling device at a blood vessel branch. When such a stent is formed of a polymer, it is difficult to determine the position of the branch portion of the stent when the stent is placed for the above reasons, but it is desirable to place the stent so that the branch portion of the stent is on the branch portion side of the blood vessel. For this reason, when placing a structurally asymmetric stent formed of an X-ray transparent material, there has been a demand for a technique that makes it easy to determine the orientation of the stent (positional relationship between each part of the stent).

  Further, when the stent is placed, the diameter of the stent is expanded to an appropriate diameter in consideration of the diameter before and after the treatment site in the target blood vessel. In the case of the balloon expandable type, for example, based on prior data that roughly defines the relationship between the internal pressure of the tube and the diameter of the expanded stent, the amount of dedicated liquid that flows into the tube of the balloon catheter is adjusted, and the stent is Expand the diameter. However, even in the case of a polymer stent that cannot be identified by an X-ray image, if the indwelling operation can be performed while confirming the diameter of the stent by the X-ray image, the diameter can be adjusted more accurately. For this reason, there has been a demand for a technique different from the conventional technique for making it easy to determine the diameter when placing a stent formed of an X-ray transparent material or in an examination after placement.

  Also, in drug-eluting coronary stents, the stent may break after placement of the stent. This is thought to be due to the large deformation (bending) of the stent after placement due to the large blood vessel movement accompanying the heartbeat. For this reason, a technique different from the conventional technique for preventing the fracture of the stent has been demanded as a stent formed of an X-ray transparent material.

  In the case of a metal stent, the position in the body can be identified by an X-ray image, but the length of the metal stent on the X-ray image varies depending on the X-ray irradiation direction to the metal stent. That is, if the central axis direction (stent length direction) when the metal stent is regarded as a tube is orthogonal to the X-ray irradiation direction, the metal stent is projected the longest in the X-ray image. On the contrary, when the central axis direction of the metal stent and the X-ray irradiation direction coincide with each other, the metal stent is projected to the smallest size in the X-ray image. On the other hand, when an indwelling site of a stent is examined with an X-ray diagnostic apparatus, it is desirable that the length of the stent can be easily determined regardless of the X-ray irradiation direction. For this reason, as a stent formed of an X-ray transmissive material, there is a demand for a technique that makes it easy to determine the length of a stent regardless of the X-ray irradiation direction in an inspection using an X-ray diagnostic apparatus after placement. It was.

  An object of an embodiment of the present invention is to provide a technique for easily determining whether or not a plurality of stents formed of an X-ray transmissive material are placed on top of each other.

  An object of another embodiment of the present invention is that each of the X-ray diagnostic apparatus side does not place an operation burden on a user when a plurality of stents formed of an X-ray transparent material are placed. It is to provide a technique for detecting the position of each stent.

  An object of another embodiment of the present invention is to make it easy to determine the orientation of the stent (positional relationship of each part of the stent) when placing a structurally asymmetric stent formed of an X-ray transparent material. Is to provide technology for.

  Another object of the present invention is to provide a technique different from the conventional technique for easily determining the diameter of a stent formed of an X-ray transparent material or in an inspection after placement. Is to provide.

  An object of another embodiment of the present invention is to provide an unconventional technique for preventing fracture of a stent formed of a radiolucent material.

  Another object of the present invention is to provide a length of the stent regardless of the X-ray irradiation direction in an inspection using an X-ray diagnostic apparatus after placement of the stent formed of an X-ray transparent material. It is to provide a technique for facilitating the determination.

  In each embodiment of the stent described below as an example, the stent has a tubular structure that is formed of an X-ray transmissive material so that the diameter can be increased and a gap is formed. Hereinafter, although each embodiment of a stent is described for each item, the first marker, the second marker, and the third marker of each embodiment described below are all formed of a radiopaque material.

  (1) In the stent of one embodiment, a first marker is provided on one end side of the tubular structure. A second marker having a size larger than that of the first marker is provided on the other end side of the tubular structure.

  (2) In the stent according to another embodiment, the first marker is provided on one end side of the tubular structure. On the other end side of the tubular structure, a second marker having a width of 40 μm or more at a portion different from the shape of the first marker is provided.

  (3) The stent according to another embodiment includes at least one first marker provided on one end side of the tubular structure and a plurality of second markers. These second markers are provided on the other end side of the tubular structure and are larger in number than the first markers.

  (4) A stent according to another embodiment includes a first marker and a second marker provided on one end side and the other end side of a tubular structure, respectively. The CT value is determined so that the water is 0 and the human tissue is 1000, and the CT value of the pixel region corresponding to the first marker when the image is taken by the X-ray diagnostic apparatus under the condition of the tube voltage of 100 kilovolts, The first and second markers have different X-ray transmittances so that the CT values of the pixel regions corresponding to the two markers differ by 10 or more.

  (5) The stent according to another embodiment includes a first marker and a second marker provided on one end side and the other end side of the tubular structure, respectively, and at least one third marker. The third marker is provided in the central region of the tubular structure.

  (6) A stent according to another embodiment includes a first marker and a second marker provided on one end side and the other end side of the tubular structure, respectively, and at least one third marker. The third marker is provided between the first and second markers in the tubular structure so that the distance between the markers including the first and second markers is substantially equal.

  (7) A stent according to another embodiment includes a branched portion branched from the middle of the tubular structure as a part of the tubular structure, a first marker provided on one end side of the tubular structure, and a tubular shape. A second marker provided on the other end of the structure; and a third marker provided on a branch portion of the tubular structure.

  (8) The stent according to another embodiment has an asymmetric shape in which one of the divided and the other is different from each other when the tubular structure is divided into two along the direction from the one end side to the other end side. A first marker and a second marker provided on one end side and the other end side of the tubular structure, respectively, and a third marker provided between the one end side and the other end side of the divided one.

  (9) The stent according to another embodiment includes at least three markers that are spaced apart from each other so as to make one round of a cross section parallel to the diametrical direction of the tubular structure.

  (10) A stent according to another embodiment includes at least ten markers provided at positions along a spiral trajectory from one end side to the multi-end side of a tubular structure.

Next, the X-ray diagnostic apparatus of the present invention will be described.
In one embodiment, the X-ray diagnostic apparatus includes an X-ray detection unit, an image data generation unit, a marker detection unit, and an identification processing unit.
The X-ray detection unit has X-rays transmitted through a subject including a plurality of X-ray transmissive stents, each having an X-ray impermeable marker on one end side and the other end side. It detects with a detection element and outputs the electric signal according to X-ray dose for every X-ray detection element.
The image data generation unit generates image data of an X-ray image of the subject so that the luminance of each pixel becomes a luminance corresponding to the electrical signal for each X-ray detection element.
The marker detection unit detects, as a marker, a pixel region in which the difference in contrast with the surroundings is a predetermined value because the X-ray dose detected by the X-ray detection element is smaller than that in the surroundings in the image data.
When four or more markers are detected in the image data of one X-ray image, the identification processing unit has a difference in size between markers, a difference in shape between markers, a difference in X-ray transmittance between markers, The stent to which each marker belongs is identified based on at least one of the number difference between the number of markers on one end side and the number of markers on the other end side.

The typical sectional view showing the composition of the stent system of a 1st embodiment. The plane schematic diagram which shows an example of the X-ray image by the X-ray diagnostic apparatus at the time of placing two stents of 1st Embodiment, and the estimated distance of the stent. The plane schematic diagram which shows another example of the X-ray image by the X-ray diagnostic apparatus at the time of placing two stents of 1st Embodiment, and the estimated overlap of the stent. The plane schematic diagram which shows the example of the X-ray image by the X-ray diagnostic apparatus at the time of detaining two conventional polymer stents, and the overlapping condition or separation condition of a polymer stent. The plane schematic diagram which shows the structure of the stent in the stent system of 2nd Embodiment. The plane schematic diagram which shows the structure of the stent in the stent system of 3rd Embodiment. The plane schematic diagram which shows the structure of the modification of the stent of 3rd Embodiment. The plane schematic diagram which shows the structure of another modification of the stent of 3rd Embodiment. The plane schematic diagram which shows the structure of the stent in the stent system of 4th Embodiment. The plane schematic diagram which shows the structure of the stent in the stent system of 5th Embodiment. The plane schematic diagram which shows the structure of the stent in the stent system of 6th Embodiment. The schematic diagram of the X-ray image of the stent 20h when X-rays are irradiated perpendicularly to the central axis direction of the stent 20h in FIG. FIG. 12 is a schematic diagram of an X-ray image when X-rays are irradiated obliquely with respect to the central axis direction of the stent 20h in FIG. The plane schematic diagram which shows the structure of the stent in the stent system of 7th Embodiment. The plane schematic diagram which shows the modification of the stent of 7th Embodiment. The plane schematic diagram which shows another modification of the stent of 7th Embodiment. The plane schematic diagram which shows the structure of the stent of the stent system of 8th Embodiment at the time of seeing a patch from the upper side. The plane schematic diagram which shows the structure of the stent of 8th Embodiment at the time of seeing from the direction orthogonal to the case of FIG. The plane schematic diagram which shows the structure of the stent in the stent system of 9th Embodiment. The cross-sectional schematic diagram which shows the structure of the stent of 9th Embodiment. The schematic plan view which shows the structure of the stent in the stent system of 10th Embodiment. In 10th Embodiment, it is explanatory drawing of the number of markers in the case of arrange | positioning a marker helically, The plane schematic diagram which looked at the stent from the direction orthogonal to the central axis. The plane schematic diagram which shows the structure of the stent in the stent system of 11th Embodiment. The block diagram which shows the structure of the X-ray diagnostic apparatus in 12th Embodiment. It is explanatory drawing of an example of the detection method of the marker position for every stent, and is a plane schematic diagram which shows an example of the X-ray image of the subject in which the two stents 20a of 1st Embodiment were detained in the body. It is explanatory drawing of an example of the detection method of the marker position for every stent, and is a plane schematic diagram which shows an example of the X-ray image of the subject in which the stent 20a of 1st Embodiment was detained in the body. It is explanatory drawing of another example of the detection method of the marker position for every stent, and is a plane schematic diagram which shows an example of the X-ray image of the subject in which the stent 20e of 3rd Embodiment was detained in the body. It is explanatory drawing of another example of the detection method of the marker position for every stent, and is a plane schematic diagram which shows an example of the X-ray image of the subject in which the stent 20f of 4th Embodiment was detained in the body. Explanatory drawing regarding the prior information of the marker for detecting the marker position for every stent, when the stent 20b of 2nd Embodiment is detained in the body. The plane schematic diagram which shows the detection method of the marker position for every stent in the X-ray image of the subject in which the stent 20b of 2nd Embodiment was detained in the body. The schematic diagram which shows an example of the X-ray image displayed on the display part of a X-ray diagnostic apparatus for selection of a tracking stent. The schematic diagram which shows an example of the region of interest automatically set by the system control part 92 of an X-ray diagnostic apparatus based on the X-ray image used for selection of the tracking stent. The schematic diagram which shows another example of the region of interest automatically set by the system control part 92 of an X-ray diagnostic apparatus based on the X-ray image used for selection of the tracking stent. The schematic diagram which shows the identification method of the tracking stent by the stent detection part 86a of an X-ray diagnostic apparatus. The schematic diagram which shows an example of the display image displayed as a moving image after the selection when two stents are selected as a tracking stent. The schematic diagram which shows another example of the display image displayed as a moving image, when one stent is selected as a tracking stent. The flowchart which shows operation | movement of the X-ray diagnostic apparatus of 12th Embodiment. Explanatory drawing which shows the discrimination function of the stent to which each marker by 12th Embodiment belongs, and the difference with a prior art. Explanatory drawing which compared 12th Embodiment and the prior art from a viewpoint of the region of interest to be set.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In addition, in each figure, the same code | symbol is attached | subjected to the same element and the overlapping description is abbreviate | omitted.

(First embodiment)
FIG. 1 is a schematic cross-sectional view showing the configuration of the stent system 8 of the first embodiment. As shown in FIG. 1, the stent system 8 includes a catheter 10, a guide wire 14 inserted through the tube portion 12 of the catheter 10, a balloon 16, markers 18 a and 18 b, and a stent 20 a. In FIG. 1, only the stent 20a and the markers 18a and 18b are shown in a plan view, and other elements are shown as schematic cross-sectional views in order to facilitate understanding of the mesh structure of the stent 20a and the markers 18a and 18b.

The catheter 10 has a tubular structure. A hollow region (shaded portion in FIG. 1) other than the tube portion 12 for inserting the guide wire 14 in the catheter 10 is filled with a dedicated liquid for inflating the balloon 16 when the diameter of the stent 20a is expanded.
The balloon 16 is attached to the distal end portion of the catheter 10.

  Each of the markers 18 a and 18 b is provided so as to make one round of the outer periphery of the tube portion 12 in the catheter 10. The positions of the markers 18a and 18b are positions facing the both ends of the balloon 16, respectively. Since the markers 18a and 18b are made of a radiopaque material, they can be identified in an X-ray image. Therefore, when the diameter of the stent 20a is expanded, the positions of the balloon 16 and the stent 20a can be identified by confirming the positions of the markers 18a and 18b with X-ray images.

  The stent 20a is a balloon expandable type, and includes a tubular structure 22a and markers 24α and 24β made of a radiopaque material. The tubular structure 22a is a bioabsorption type, and is formed in a mesh shape and capable of expanding its diameter by an X-ray transmissive material. Due to the mesh shape, a large number of gaps are formed for allowing the liquid flowing into one end side of the tubular structure 22a to flow outside the other end side of the tubular structure 22a.

  The tubular structure 22a is a structure in which, for example, a mesh is folded, and the folding is expanded when the diameter is expanded, so that the material itself constituting the mesh does not extend greatly. What is necessary is just to form such a tubular structure 22a with polymers, such as poly-L-lactic acid (PLLA: poly-L-lactic acid), for example. The material of the tubular structure 22a is not limited to a polymer, and may be other X-ray transmissive materials (the same applies to other embodiments described later).

  Here, the X-ray transparent material means an X-ray absorptivity that is low and it is difficult to identify its shape in an X-ray image taken by an X-ray diagnostic apparatus. An X-ray transparent material is, for example, an image taken with an X-ray diagnostic apparatus at a tube voltage of 100 to 120 kV (kilovolts) so that air is −1000, water is 0, and human tissue such as blood and blood vessels is about 1000. When the CT value is determined, the difference between the CT value and the human tissue is about 10 or less. CT value (Computed Tomography Value) represents the X-ray absorption rate of a substance as a relative value with respect to a reference substance such as water. In the X-ray image, each pixel has a pixel value based on the CT value as data, and the luminance level of each pixel is defined according to the pixel value.

  An X-ray opaque material is a material that has a high X-ray absorptivity (for example, about the same as metal) and that can identify its shape in an X-ray image taken by an X-ray diagnostic apparatus. The CT value differs from the X-ray transparent material by, for example, about 100 or more. In addition, the above description regarding X-ray permeability and X-ray opaqueness is only an interpretation example, and does not limit the present invention.

  Since the tubular structure 22a is formed in a mesh shape, the tubular structure 22a has a structure having a large number of gaps that allow blood or the like flowing into one end side thereof to flow out other than the other end side. However, the gap structure for flowing the blood flow also to the thin blood vessel branched from the blood vessel in which the stent 20a is placed is not limited to the mesh shape. The tubular structure may have other shapes such as a coil shape.

  The markers 24α and 24β are made of a radiopaque material. The marker 24α is provided on one end side of the tubular structure 22a (for example, bonded), and the marker 24β is provided on the other end side of the tubular structure 22a. Here, the “one end side” is, for example, within 10% from the end of the tubular structure 22a having an annular cross section when viewed in the central axis direction of the tubular structure 22a (the extending direction of the guide wire 12 in FIG. 1). It is an area. More preferably, the region is within 5% from the end of the tubular structure 22a so that the length of the stent can be more accurately determined based on the position of the marker in the X-ray image. The same applies to the “other end side”.

  Examples of the material of the markers 24α and 24β include cobalt chrome, stainless steel, platinum, and the like. However, the materials of the markers 24α and 24β may be other materials as long as they are radiopaque and harmless to the human body. One of the features of this embodiment is that the sizes of the markers 24α and 24β are different. In the example of FIG. 1, the marker β is larger than the marker 24α, but the arrangement may be reversed.

  Here, the dimension of the smaller marker (marker 24α in the example of FIG. 1) is desirably 40 μm (microns) or more, as will be described below. Here, the dimension refers to, for example, the length of the longest one side in the smallest rectangular parallelepiped including the marker, and the diameter is the dimension if the marker is, for example, a disk shape.

  In general, the smaller the size of each detection element in the X-ray detector in the X-ray diagnostic apparatus, that is, the pixel size, the more the number of pixels can be increased, so that the resolution can be improved. However, as one pixel is smaller, the X-ray dose that passes through the subject and reaches the pixel decreases, and the signal (X-ray dose that reaches the pixel) and noise (SN ratio) decrease. Specifically, the pixel signal output from each detection element (pixel) includes not only a signal component proportional to the irradiated X-ray dose, but also a noise component that does not depend on the X-ray dose as fixed pattern noise that differs for each pixel. Including. Further, readout noise and the like in a circuit inside the X-ray detector and a signal processing circuit subsequent to the X-ray detector in the X-ray diagnostic apparatus are added to the noise component. Some of these noise components also depend on temperature.

  When using an X-ray diagnostic apparatus at room temperature (for example, 300 Kelvin), noise tends to be dominant over signal components when the size of each pixel is less than 50 μm. This is a general understanding of the contractor. There is no need to increase the size of each pixel to 200 μm or more in order to improve the S / N ratio. However, even if the pixel size is reduced, it is a general understanding of those skilled in the art at the time of filing this application that, for example, if the pixel is a square, the pixel size is preferably about 50 μm on a side.

  Here, as the distance between the X-ray irradiation source and the X-ray detector is narrowed, the amount of X-ray attenuation decreases and the X-ray dose incident on the pixel of the X-ray detector increases. So desirable. However, since the subject is actually placed between the X-ray irradiation source and the X-ray detector, each component of the X-ray diagnostic apparatus has a sufficient margin so that the X-ray detector or the like does not contact the subject. It is desirable to arrange. In this case, if the average width between both shoulders of a Japanese adult is about 50 cm, for example, the distance between the X-ray irradiation source and the X-ray detector is preferably 120 cm or more. If the distance between the X-ray irradiation source and the subject is 45 cm or more from the viewpoint of safety, the ratio between the distance from one end of the subject to the X-ray irradiation source and the distance from the X-ray irradiation source to the X-ray detector Is close to 95: 120 (approximately 4: 5), or the difference further widens.

  This is because a 10 cm object in the body of the subject is projected to 10 × (5/4) = 12.5 cm on the pixel array surface (surface receiving X-rays) of the X-ray detector in the minimum case. Means that. Then, even when the pixel size of the X-ray diagnostic apparatus is small as described above (50 μm per side), in order to project the marker as one pixel on the X-ray image, the dimension of the marker is 50 μm ÷ (5 / 4) = 40 μm or more is desirable.

  When the dimension of the marker 24α is considered to be the minimum size of 40 μm, in order to recognize the difference in size between the markers 24α and 24β, the X-ray transmitted through the larger marker 24β is sufficiently spread over at least two pixels. It is desirable to enter. That is, the dimension of the marker 24β is 50 μm × 2 ÷ (5/4), which is 80 μm. That is, in order to recognize the difference in size between the markers 24α and 24β, it is desirable that the dimensional difference between them is 40 μm or more that can be distinguished as a difference for one pixel of the X-ray detector. More preferably, the dimensional difference between the two is 80 μm or more that can be distinguished as a difference of two pixels of the X-ray detector. More preferably, the dimensional difference between the two is desirably 120 μm or more that can be distinguished as a difference for three pixels of the X-ray detector.

  In addition, it is desirable that the upper limit value of the dimension of the markers 24α and 24β is, for example, within a range of one mesh of the tubular structure 22a. If it mentions functionally, the upper limit of the dimension of marker 24 (alpha), 24 (beta) is a grade which can maintain the blood flow to the fine blood vessel branched from the blood vessel by which the stent 20a is arrange | positioned and is expanded favorably. This is because as the markers 24α and 24β are larger, blood flow from the blood vessel in which the stent 20a is arranged to the thin blood vessel branching is restricted. In the present embodiment, as an example, the marker 24α has a disk shape with a diameter of 50 μm and a thickness of 50 μm, and the marker 24β has a disk shape with a diameter of 170 μm and a thickness of 130 μm.

  FIG. 2 is a schematic plan view showing an example of an X-ray image obtained by the X-ray diagnostic apparatus in the case where two stents 20a are indwelled and an estimated degree of separation of the stent 20a. As described above, the stent 20a has the markers 24α and 24β that can be identified by the difference in size on the X-ray image on one end side and the other end side, respectively. Therefore, the X-ray image as shown in FIG. When it is obtained, as shown in FIG. 2B, it can be easily determined that the two stents 20a are separated from each other.

  FIG. 3 is a schematic plan view showing another example of an X-ray image obtained by the X-ray diagnostic apparatus when two stents 20a are placed, and an estimated overlapping state of the stent 20a. When an X-ray image as shown in FIG. 3A is obtained, it can be easily determined that the two stents 20a overlap each other as shown in FIG. 3B for the same reason as described above. For comparison with the present embodiment, the case of a conventional polymer stent will be described below.

  FIG. 4 is a schematic plan view showing an example of an X-ray image obtained by an X-ray diagnostic apparatus when two conventional polymer stents are placed, and how the polymer stent is overlapped or separated. As shown in FIGS. 4B and 4C, the conventional polymer stent 40 is provided with markers 42 that are at least equal on one end side and the other end side so that they cannot be discriminated at least by an X-ray image. The marker 42 is radiopaque. Therefore, when an X-ray image as shown in FIG. 4 (A) is obtained, whether two polymer stents 40 are separated as shown in FIG. 4 (B) or 2 as shown in FIG. 4 (C). It could not be determined whether the two polymer stents 40 partially overlapped. On the other hand, according to the present embodiment, as described above, this conventional problem is solved.

(Second Embodiment)
In the stent system of each of the following embodiments, only the stent is different from the first embodiment, and the configuration of other elements such as the catheter 10 is the same. Therefore, the overlapping description and drawings are omitted, and the configuration of the stent is omitted. Focus on and explain.

  FIG. 5 is a schematic plan view showing the configuration of the stent 20b in the stent system of the second embodiment. As shown in FIG. 5, the stent 20b has a tubular structure 22b and three markers 24b1, 24b2, and 24b3. The tubular structure 22b has the same configuration as the tubular structure 22a of the first embodiment except for the arrangement and configuration of the markers 24b1 to 24b3 (about third to sixth and eighth to eleventh embodiments described later). The same).

  One marker 24b1 is provided on one end side of the tubular structure 22b (for example, bonded), and two markers 24b2 and 24b3 are provided on the other end side of the tubular structure 22b. Here, as an example, the markers 24b1 to 24b3 all have the same size, shape, and material, and the size, shape, and material may be the same as, for example, the marker 24α or the marker 24β of the first embodiment.

  The distance between the two markers 24b2 and 24b3 on one end side of the tubular structure 22b is preferably such that the distance can be recognized on the X-ray image, and is preferably 40 μm or more for the above-described reason. More preferably, the interval between the two markers 24b2 and 24b3 on one end side of the tubular structure 22b is preferably 80 μm or more, and more preferably 120 μm or more.

  In the stent 20b having the above-described configuration, one end side and the other end side of the stent 20b can be identified by the difference in the number of markers (24b1 to 24b3) in the X-ray image. Therefore, the same effect as that of the first embodiment can be obtained. Note that the number of markers arranged in the X-ray image is not limited to that shown in FIG. 5 because it is only necessary to identify the one end side and the other end side of the stent 20b by the difference in the number of markers. For example, the number may be five on one end side and one on the other end side of the stent 20b. Further, the size, shape, and material of each marker 24b1 to 24b3 may be different from each other.

(Third embodiment)
FIG. 6 is a schematic plan view showing the configuration of the stent 20c in the stent system of the third embodiment. As shown in FIG. 6, the stent 20c includes a tubular structure 22c, a marker 24c1 provided on one end side of the tubular structure 22c, and a marker 24c2 provided on the other end side of the tubular structure 22c.

  In the present embodiment, as an example, the marker 24c1 is a rectangular parallelepiped having a length of 400 μm, a width of 200 μm, and a thickness of 200 μm, and the marker 24c2 has a spherical shape with a diameter of 80 μm. In this case, the width of the difference in shape of the markers 24c1 and 24c2 is 200 μm−80 μm = 120 μm when viewed from any direction. Therefore, by irradiating X-rays from any direction, the markers 24c1 and 24c2 can be recognized as a difference in shape of three pixels or more even when the stent 20c is viewed as an X-ray image. That is, since the one end side and the other end side of the stent 20c can be identified by the difference in the shape of the markers 24c1 and 24c2 in the X-ray image, the same effect as in the first embodiment can be obtained.

  Note that the shapes and dimensions of the markers 24c1 and 24c2 described above are merely examples, and it is sufficient that there is a difference in shape and dimensions so that one end side and the other end side of the stent can be identified by an X-ray image. Specifically, for the same reason as described above, it is desirable that the width of the difference in shape is 40 μm or more that can be recognized as one pixel. More preferably, the width of the part having a different shape is preferably 80 μm or more that can be recognized as two pixels, and more preferably 120 μm or more that can be recognized as three pixels.

  FIG. 7 is a schematic plan view showing a configuration of a modified example of the stent of the third embodiment. As shown in FIG. 7, the stent 20d includes a tubular structure 22d, a marker 24d1 provided on one end side of the tubular structure 22d, and a marker 24d2 provided on the other end side of the tubular structure 22d. For example, the marker 24d1 is a regular triangle having a side of 150 μm when viewed in a plane as projected onto a two-dimensional image (for example, when viewed three-dimensionally, the markers 24d1 face each other at an interval of 80 μm corresponding to the thickness. The pentahedron whose front surface and back surface are regular triangles with a side of 150 μm and whose three side surfaces are both 80 μm in width is bent slightly in an arc along the arrangement portion of the tubular structure 22d. Shape).

  The marker 24d2 (the thick line portion in FIG. 7) is formed on the mesh so as to follow the entire mesh on the other end side of the tubular structure 22d.

  FIG. 8 is a schematic plan view showing the configuration of another modification of the stent of the third embodiment. As shown in FIG. 8, the stent 20e includes a tubular structure 22e, a marker 24e1 provided on one end side of the tubular structure 22e, and a marker 24e2 provided on the other end side of the tubular structure 22e. The marker 24e1 is, for example, a cross having a top surface and a bottom surface of 250 μm in length and a thickness of 80 μm. The marker 24e2 has a cubic shape with a side of 120 μm, for example. In the case of each modification shown in FIGS. 7 and 8, the X-ray image can identify the one end side and the other end side of the stents 20d and 20e by the difference in the shape of the marker, and thus the same as the stent 20c shown in FIG. An effect is obtained.

(Fourth embodiment)
FIG. 9 is a schematic plan view showing the configuration of the stent 20f in the stent system of the fourth embodiment. As shown in FIG. 9, the stent 20f includes a tubular structure 22f, a marker 24f1 provided on one end side of the tubular structure 22f, and a marker 24f2 provided on the other end side of the tubular structure 22f.

  In this embodiment, as an example, the markers 24f1 and 24f2 are both disk-shaped with a diameter of 200 μm and a thickness of 100 μm. In the present embodiment, the one end side and the other end side of the stent 20f are identified based on the density difference between the markers 24f1 and 24f2 in the X-ray image.

  As an example, the marker 24f1 has an X-ray transmittance twice that of the marker 24f2 (for example, when X-ray irradiation is performed under the conditions of a tube voltage of 80 kilovolts, a tube current of 100 milliamperes, and a pulse width of 10 milliseconds). is there. This can be realized by appropriately changing the material and composition ratio of the marker such as cobalt chrome.

  Alternatively, by forming the markers 24f1 and 24f2 with the same material and changing the density inside the markers (partially hollow), the X-ray transmittance of both can be changed. Or although it is formed with the same material instead of the markers 24f1 and 24f2, the X-ray transmittance of both can be changed as described above by providing two markers having different thicknesses.

  Here, in order to discriminate one end side and the other end side of the stent 20f by the difference in density between the markers 24f1 and 24f2 in the X-ray image, for example, the X-ray transmittances of the markers 24f1 and 24f2 are equal to each other to the extent that the following conditions are satisfied. It is desirable to be different. Specifically, for example, an X-ray diagnostic apparatus is used for imaging under a tube voltage of 100 to 120 kilovolts, and the CT value is set so that air is −1000, water is 0, and human tissue such as blood and blood vessels is about 1000. When determined, it is desirable that the CT value of the pixel corresponding to the marker 24f1 and the CT value of the pixel corresponding to the marker 24f2 differ by 10 or more.

  This is because, at the technical level at the time of filing of the present application, if the CT values of the pixels corresponding to the two objects in the X-ray image differ by about 10 or more, they can be distinguished as two different objects. Specifically, variations in the sensitivity of each detection element in the X-ray detector of the X-ray diagnostic apparatus, movement of the subject during imaging such as circuit noise of the X-ray detector, breathing, etc. (a thick subject) This is because, in consideration of individual differences in the subject (such as noise that increases as much as possible), if the difference in CT value is less than 10, it is difficult to distinguish between two different objects according to the technical level at the time of filing this application.

  More preferably, for example, when imaging is performed under the above conditions and the CT values are determined as described above, it is preferable that the CT values corresponding to the markers 24f1 and 24f2 differ by 20 or more (which is twice the above), More desirably, the values differ by 30 or more (which is 3 times the above). This is because the density difference between the markers 24f1 and 24f2 appears larger in the X-ray image, making it easier to distinguish one end side and the other end side of the stent 20f.

  As described above, in the fourth embodiment, since one end side and the other end side of the stent 20f can be identified by the density difference between the markers 24f1 and 24f2 in the X-ray image, the same effect as that of the first embodiment can be obtained.

(Fifth embodiment)
FIG. 10 is a schematic plan view showing the configuration of the stent 20g in the stent system of the fifth embodiment. FIG. 10A shows an initial state in which no external force is applied to the stent 20g, and FIG. 10B shows a bent state in which an external force is applied to the stent 20g. As shown in FIG. 10, the stent 20g includes a tubular structure 22g, a marker 24g1 provided on one end of the tubular structure 22g, a marker 24g2 provided on the other end of the tubular structure 22g, and a tubular structure. And a marker 24g3 provided at an intermediate position in the length direction of the body 22g.

  The stent 20g is a balloon expandable type. The tubular structure 22g is a bioabsorption type, and is formed so as to be mesh-shaped and capable of expanding its diameter with a material having X-ray permeability and sufficient elasticity. Here, “having sufficient elasticity” means that the stent 20g is placed in a blood vessel having a large movement, such as a coronary artery, and the tubular structure 22g does not break even if it is bent as shown in FIG. It is elastic. What is necessary is just to form such a tubular structure 22a with polymers, such as the above-mentioned PLLA, for example.

  The markers 24g1, 24g2, and 24g3 are formed of a radiopaque material as in the first embodiment. In this embodiment, as an example, the marker 24g2 has a cubic shape with a side of 80 μm, for example, and the marker 24g3 has a spherical shape with a diameter of 120 μm, for example. Further, as an example, the marker 24g1 is larger than the markers 24g2 and 24g3 and has, for example, a rectangular parallelepiped shape of 300 μm × 160 μm × 160 μm. Accordingly, since one end side and the other end side of the stent 20g can be identified by the difference in size of the markers 24g1 and 24g3 in the X-ray image, the same effect as in the first embodiment can be obtained.

  Here, for example, a drug-eluting coronary stent is considered to have a large bend in the stent after placement because the blood vessel movement accompanying the heartbeat is large as described above. When such a stent is formed of a bioabsorbable material, it does not appear in the X-ray image, and thus it has not been possible to evaluate the degree of bending. However, in the case of the (bioabsorbable) stent 20g of the present embodiment, the bending condition of the stent 20g depends on the positions of the markers 24g1 to 24g3 in the X-ray image, for example, by periodically performing an examination using an X-ray diagnostic apparatus. Can be judged.

  That is, since the shapes and dimensions of the three markers 24g1 to 24g3 are different from each other so that they can be recognized in the X-ray image, even if the stent 20g is bent greatly, which two markers are markers on both ends of the stent 20g in the X-ray image. Can be determined. If the markers 24g1 to 24g3 are substantially in a straight line, it can be determined that the stent 20g is not bent. On the contrary, it can be determined that the stent 20g is bent as the marker 24g2 is further away from the straight line connecting the marker 24g1 and the marker 24g3. Therefore, for example, when it is recognized that the bending of the stent 20g has reached a predetermined level by periodic inspection, the stent can be prevented from being broken by performing an appropriate treatment such as replacement.

  In the fifth embodiment, the same effect as in the first embodiment is obtained by changing the size of the markers 24g1, 24g2 at both ends. However, this is not essential, and the markers 24g1, 24g2 at both ends (or all markers) are obtained. May be the same (the same applies to sixth to tenth embodiments described later). Even if the size and shape of each of the markers 24g1 to 24g3 are the same, the degree of bending of the stent 20g can be determined by an X-ray image, which is also included in the technical idea of the present embodiment. However, it is desirable for the above-described reason that the markers 24g1, 24g2, and 24g3 can be distinguished from each other in the X-ray image by changing the shape and dimensions, for example.

  In order to evaluate the degree of bending of the stent, it is desirable to provide at least three markers (one at each end of the tubular structure and one at the center). In the case where a plurality of markers are provided approximately linearly at intervals from one end side to the other end side of the tubular structure, for example, 10 markers are sufficient for evaluating the degree of bending of the stent. It is done. The upper limit of the number of markers is that the interval between the markers is ensured to the extent that the portion with and without the marker can be identified even when the size of one pixel of the X-ray detection element in the X-ray diagnostic apparatus is large. desirable.

(Sixth embodiment)
FIG. 11 is a schematic plan view showing the configuration of the stent 20h in the stent system of the sixth embodiment. As shown in FIG. 11, the stent 20h includes a tubular structure 22h and markers 24h1, 24h2, 24h3, 24h4, 24h5, and 24h6 provided on the tubular structure 22h.

  The marker 24h1 has, for example, a cubic shape with a side of 160 μm and is larger than the markers 24h2 to 24h6. Each of the markers 24h2 to 24h6 has the same shape and size, for example, a spherical shape having a diameter of 80 μm. The marker 24h1 is located on one end side of the tubular structure 22h, and the marker 24h6 is located on the other end side of the tubular structure 22h. The markers 24h1 to 24h6 are positioned so that the line connecting them becomes a straight line and the interval L between the markers 24h1 to 24h6 is equal to 5 mm, for example. The interval L between the markers 24h1 to 24h6 here is not an interval between the outer edges of the markers 24h1 to 24h6 but an interval between the centers of the markers as an example.

  12 and 13 are schematic plan views showing the difference in the X-ray image of the stent 20h depending on the X-ray irradiation direction. FIG. 12A is an example of an X-ray image when X-rays are irradiated perpendicularly to the central axis direction of the stent 20h, and FIG. 12B is estimated from the X-ray image of FIG. The position of the stent 20h is shown. FIG. 13 (A) is an example of an X-ray image when X-rays are irradiated obliquely with respect to the central axis direction of the stent 20h, and FIG. 13 (B) is an X-ray image of FIG. 13 (A). The estimated position of the stent 20h is shown.

  When X-rays are irradiated perpendicularly to the central axis direction of the stent 20h, the stent 20h is projected most greatly in the X-ray image as shown in FIGS. However, the more the X-ray irradiation direction is inclined, that is, the closer the X-ray irradiation direction is to the central axis direction of the stent 20h, the smaller the stent 20h is projected in the X-ray image (FIGS. 13A and 13B). reference). That is, the length of the stent 20h in the X-ray image (how it appears) varies depending on the orientation of the stent placed in the subject (X-ray irradiation direction). The size of the stent in the subject could not be determined.

  However, in the case of the stent 20h of the present embodiment, as long as information on the distance between markers (for example, 5 mm) is obtained in advance, even if a large number of stents are contained in the same subject, the X-ray irradiation direction does not matter. The length of the stent shown in the X-ray image can be determined from the number of markers. Moreover, in the stent of this embodiment, since both ends can be determined by the difference in size of the markers 24h1 and 24h6, the same effect as that of the first embodiment can be obtained. Furthermore, since the markers 24h2 to 24h5 are provided between the markers 24h1 and 24h6 at both ends, the same effect as that of the fifth embodiment can be obtained.

  In addition, in the stent 20h of this embodiment, although the magnitude | size of the markers 24h1 and 24h6 of both ends was changed, you may make all the markers 24h1-24h6 the same. In this case, although the same effect as the first embodiment cannot be obtained, it is included in the technical idea of the present embodiment in which the length of the stent is determined by the number of markers.

  Further, in order to determine the length of the stent shown in the X-ray image by the number of markers regardless of the X-ray irradiation direction, the number of markers provided at substantially equal intervals and substantially linearly with respect to the tubular structure 22h. Is preferably 3 or more. As an upper limit of the number of markers, it is desirable that an interval between markers is ensured so that a portion with and without a marker can be identified even when the size of one pixel of an X-ray detection element in the X-ray diagnostic apparatus is large. .

  Further, the interval between the markers does not need to be completely equal as in the present embodiment, but may be close enough to determine the length of the stent based on the number of markers shown in the X-ray image. Considering the pixel size of the X-ray detection element in the X-ray diagnostic apparatus, it can be said that “the interval between the markers is substantially equal” if it is close enough to be indistinguishable on the X-ray image. That is, for the reason described in the first embodiment, when the difference in the interval between the markers is at least less than 40 μm, the interval between the markers is substantially equal, and is included in the technical idea of the present embodiment.

(Seventh embodiment)
FIG. 14 is a schematic plan view showing the configuration of the stent 20i in the stent system of the seventh embodiment. As shown in FIG. 14, the stent 20i has a tubular structure 22i and radiopaque markers 24i1, 24i2, and 24i3.

  One of the differences from the above-described embodiments is that a part of the tubular structure 22i is branched in a branch shape from the center of the tubular structure 22i as a branching portion 26i. The tubular structure 22i is the same as each of the above embodiments in that the tubular structure 22i is formed of a X-ray transparent and bioabsorbable material so as to be mesh-shaped and capable of expanding its diameter.

  The marker 24i1 has a cubic shape with a side of 160 μm, for example. The markers 24i2 and 24i3 have the same shape and size, for example, a spherical shape with a diameter of 80 μm. The markers 24i1 and 24i2 are provided on one end side and the other end side of the tubular structure 22i, respectively. The marker 24i3 is provided at the branch point of the tubular structure 22i.

  In the conventional polymer stent, the position of the branch point could not be confirmed in the X-ray image after placement. However, in the stent 20i of the present embodiment, since the marker 24i3 is provided at the branch point in addition to the both ends of the tubular structure 22i, the position of the branch point can be confirmed in the X-ray image. Further, since the sizes of the markers 24i1 and 24i2 at both ends are different, the same effect as in the first embodiment can be obtained.

  FIG. 15 is a schematic plan view showing a modification of the stent of this embodiment. As shown in FIG. 15, the stent 20j has a tubular structure 22j and markers 24j1, 24j2, and 24j3. The size, material, and shape of the markers 24j1 to 24j3 are the same as those of the markers 24i1, 24i2, and 24i3 in FIG. 14, and the material and shape of the tubular structure 22j, the position of the branch portion 26j, and the like are the same as those of the stent 20i in FIG. It is the same. The difference from the stent 20i of FIG. 14 is that a marker 24j3 is provided at a position facing the branch point (in the diameter direction of the tubular structure 22j), not the branch point of the tubular structure 22j. In this case, the same effect as described above can be obtained.

FIG. 16 is a schematic plan view showing another modified example of the stent of the present embodiment. As shown in FIG. 16, the stent 20k has a tubular structure 22k and markers 24k1, 24k2, 24k3, 24k4, 24k5, and 24k6. The dimension and the like of the marker 24k1 are the same as the marker 24i1 in FIG. The dimensions and the like of the markers 24k2 to 24k6 are the same as those of the marker 24i2 in FIG. 14, and the material and the like of the tubular structure 22k are the same as those of the stent 20i in FIG.
The difference from the stent 20i of FIG. 14 is that the markers 24k3 and 24k4 are provided on both sides of the branch point of the tubular structure 22k, and the markers 24k5 and 24k6 are provided on both sides of the tip of the branch part 26k. In this case, in addition to the same effect as described above, the diameter of the branch portion 26k can be measured by the positions of the markers 24k3 and 24k4. Furthermore, the position of the tip of the branching portion 26k can be specified by the markers 24k5 and 24k6.

In the stent 20i (20k, 20k) of the present embodiment, the size of the two markers 24i1, 24i2 (24j1, 24j2, 24k1, 24k2) at both ends is changed, but all the markers may be the same. In this case, although the same effect as the first embodiment cannot be obtained, it is included in the technical idea of this embodiment in which the position of the branch point is determined based on the position of the marker between the markers at both ends.
In the present embodiment, a toroidal shape is described as an example of a bifurcated stent. However, the technical idea of the present embodiment is also applicable to other bifurcated stents such as a Y-shaped stent. It is.

(Eighth embodiment)
FIG. 17 is a schematic plan view showing the configuration of the stent 20l in the stent system of the eighth embodiment, and corresponds to the case where the patch 30 is viewed from above. FIG. 18 is a schematic plan view showing the configuration of the stent 20l of this embodiment when viewed from a direction orthogonal to the case of FIG. As shown in FIGS. 17 and 18, the stent 20 l includes a tubular structure 22 l, radiopaque markers 24 l 1, 24 l 2, and 24 l 3, and a patch 30.

  The marker 2412 is, for example, a spherical shape having a diameter of 80 μm. The marker 24l1 has, for example, a cubic shape with a side of 160 μm and is larger than the marker 24l2. Since the markers 24l1 and 24l2 are provided on one end side and the other end side of the tubular structure 22l, the same effect as in the first embodiment can be obtained.

  The main difference from the first embodiment is that a patch 30 for restricting blood flow is provided and a marker 241 is provided on the patch. The patch 30 is formed of an X-ray transparent material such as plastic, for example, and is disposed on the aneurysm side, for example, and suppresses blood flow to the aneurysm.

  The stent 20l according to this embodiment has an asymmetric structure between the side where the patch 30 is present and the side where the patch 30 is not present when the stent 20l is divided so as not to pass the patch 30 in the central axis direction of the tubular structure 22l. For example, when such a stent 20l is placed in a blood vessel having an aneurysm, it is desirable that the diameter of the stent 20l is expanded after the patch 30 is on the aneurysm side to restrict blood flow to the aneurysm. It is. However, in the conventional metal stent, since the X-ray absorption rate of the metal is high, the entire stent appears black in the X-ray image. Therefore, regardless of whether the patch is X-ray transmissive or not, the state before the stent is expanded. Then I could not confirm the position of the patch.

  On the other hand, in the present embodiment, since the tubular structure 22l is radiopaque and does not appear in the X-ray image, the position of the marker 30 can be specified by the marker 24l3 on the patch 30. That is, as in this embodiment, in a structurally asymmetric stent, if a radiopaque marker is provided only on one side showing asymmetry, the orientation of the stent can be specified even before the diameter is expanded. it can. For example, in the case of a stent in which a tubular structure is formed of a radiopaque material and a drug is applied only to one side of the tubular structure, a radiopaque marker is provided on the one side. By attaching it, the side on which the medicine is applied can be specified by an X-ray image.

  Note that since the patch 30 suppresses blood flow to a predetermined site, the marker 24l3 can be enlarged to the same size as the patch 30 as long as the marker 2413 is on the patch 30. . Therefore, if the marker 24l3 is enlarged on the patch 30 to the same extent as the diameter of the patch 30 as in the present embodiment, it becomes easier to identify the patch portion in the X-ray image.

  Further, the patch itself may be made to function as a radiopaque marker by forming the patch from a metal such as Nichirol or a synthetic material of metal and plastic. In the present embodiment, the patch 30 without a hole has been described as an example. However, as long as the hole is smaller than a size that clogs blood due to platelets, a large number of fine holes may be formed in the patch.

  Moreover, although the example which provides the marker 24l3 on the patch 30 was described in this embodiment, embodiment of this invention is not limited to this aspect. For example, the position of the patch 30 may be specified on the X-ray image by providing a radiopaque marker adjacent to the patch 30. Alternatively, the position of the patch 30 may be specified on the X-ray image by providing two markers at positions slightly apart from the patch 30 and facing each other across the patch 30.

(Ninth embodiment)
FIG. 19 is a schematic plan view showing the configuration of the stent 20m in the stent system of the ninth embodiment. As shown in FIG. 19, the stent 20m has a tubular structure 22m and radiopaque markers 24m1, 24m2, 24m3, 24m4, 24m5, 24m6, 24m7, and 24m8.

  The markers 24m2 to 24m8 are the same as each other here as an example, and are, for example, spherical with a diameter of 80 μm. The marker 24m1 has, for example, a cubic shape with a side of 160 μm and is larger than the markers 24h2 to 24h6. Since the markers 24m1 and 24m2 are respectively provided on one end side and the other end side of the tubular structure 22m, the same effect as in the first embodiment can be obtained. Further, if the positions of the markers 24m3 to 24m8 are set in the vicinity of the middle between the markers 24m1 and 24m2 at both ends as in the present embodiment shown in FIG. 19, the same effects as those of the fifth embodiment can be obtained.

  FIG. 20 is a schematic cross-sectional view through the 24m3, 24m4, 24m5, 24m6, 24m7, and 24m8 portions of the stent 20m. The markers 24m3 to 24m8 are provided so as to be equidistant from each other in a cross section parallel to the diameter of the tubular structure 22m. That is, θ in FIG. 20 is 60 °, for example.

  When the diameter of the stent 20m is expanded, the diameter of the tubular structure 22m expands, but the markers 24m1 to 24m8 do not extend. That is, when the diameter of the stent 20m is expanded, the interval between the markers 24m3 to 24m8 is increased.

  Here, if the markers 24m3 to 24m8 are copied to the X-ray image at the time of diameter expansion, the range from where to where the diametrical cross section of the tubular structure 22m extends in the X-ray image can be known. In the X-ray image irradiated with X-rays from the central axis direction of the tubular structure 22m, the markers 24m3 to 24m8 appear in a ring shape, and in the X-ray image irradiated with X-rays in the diameter direction of the tubular structure 22m, the markers 24m3 to 24m8. Appears straight. That is, the markers 24m3 to 24m8 do not all overlap in the X-ray image regardless of the X-ray irradiation direction. Therefore, if the length of the longest straight line connecting any two of the markers 24m3 to 24m8 in the X-ray image is divided by the magnification of the X-ray image, the tubular shape is obtained even when the diameter is expanded regardless of the X-ray irradiation direction. The diameter of the structure 22m can be roughly determined.

  The number of markers provided along the cross section of the tubular structure 22m is desirably three or more. If the number of markers is two, in the X-ray image irradiated with X-rays from the direction of the straight line connecting the two markers, the markers overlap and the diameter is not known at all. On the other hand, if three markers are provided along the cross section of the tubular structure 22m, for example, at equal intervals with θ of 120 ° in FIG. 20, the X-ray image irradiated from any direction has a certain diameter. Because I understand.

  Further, if the number of markers provided along the cross-section of the tubular structure 22m is, for example, ten, the diameter can be measured with sufficient accuracy in the X-ray image, so it is considered sufficient. If the number of markers is too large, there is a risk that blood flow to a thin blood vessel that branches in a branch shape from the middle of the blood vessel in which the tubular structure 22m is placed may be hindered. Therefore, it is desirable that the upper limit of the number of markers is such that the interval between the markers can be sufficiently identified in the X-ray image even when the pixel size in the X-ray diagnostic apparatus is large as described above.

(Tenth embodiment)
FIG. 21 is a schematic plan view showing the configuration of the stent 20n in the stent system of the tenth embodiment. The present embodiment corresponds to a modification of the ninth embodiment as a configuration that makes it easy to determine the diameter of the stent by an X-ray image. As shown in FIG. 21, the stent 20n includes a tubular structure 22n and a number of markers 24n provided for the tubular structure 22n. FIG. 21 shows 43 markers as an example.

  The markers 24n are radiopaque and are provided at regular intervals so that the trajectory connecting them is spiral (coiled). Specifically, the three-dimensional interval V between the markers 24n is considered by decomposing into the X, Y, and Z components of the X, Y, and Z coordinate systems that are orthogonal coordinate systems. First, the central axis direction of the stent 20n (the direction of the alternate long and short dash line in the figure) is the X-axis direction, the arbitrary diameter direction of the stent 20n is the Y-axis direction, and the direction orthogonal to the X-axis and Y-axis is the Z-axis direction. To do. Next, the intervals between the centers of the markers n in the X-axis direction, the Y-axis direction, and the Z-axis direction are set as an interval xx, an interval yy, and an interval zz, respectively.

  In this case, the interval V of the markers 24n viewed in three dimensions is a value obtained by adding the square of xx, the square of yy, and the square of zz and then taking the square root, for example, 0.4 mm. . In the initial state before the diameter expansion of the stent 20n, each of the intervals xx is equal, and the interval yz between the centers of the markers n in the YZ plane (the square of yy and the square of zz) (The value obtained by taking the square root after adding) is also equally spaced. Further, it is desirable that the lower limit values of the intervals xx, yy, and zz be sufficiently large so that the interval between the markers n can be identified even when the image size in the X-ray diagnostic apparatus is large.

  When the diameter of the stent 20n is expanded, the tubular structure 22n hardly extends in the central axis direction, so the interval xx does not change, and extends in the YZ plane and the interval yz becomes longer. On the other hand, since each marker 24n is provided in a spiral shape, the X-axis direction is specified based on the positions of the many markers 24n in the X-ray image of the expanded stent 20n regardless of the X-ray irradiation direction. it can. In the present embodiment, as an example, the interval between the markers 24n in the direction orthogonal to the X-axis direction specified in this way is set as an approximate value yz 'of the interval yz.

  Then, in the X-ray image, if the ratio of the length between the constant length interval xx and the approximate value yz ′ is obtained regardless of the diameter expansion, it is possible to determine how many millimeters the interval yz after the diameter expansion. In FIG. 21, as an example, when the stent 20n is viewed in a plan view from a direction perpendicular to the central axis, seven markers n are arranged in the positive Y-axis direction, and then the marker n is folded back in the negative Y-axis direction. Has been.

  In this way, since seven markers n are arranged in the positive Y-axis direction, the interval between the markers n in the Y-axis direction is 7-1 = 6. Therefore, if the approximate value yz 'is multiplied by 6, it corresponds to an approximate value of the diameter of the expanded stent 20n. That is, if each marker n is arranged so that the distance xx between the centers of each marker n in the X-axis direction is substantially equal to a predetermined value, and this predetermined value is left as information, a large number of markers appearing in the X-ray image Based on the position of n, the approximate diameter of the expanded stent 20n can be determined.

  FIG. 22 is an explanatory diagram of the number of markers when the markers are spirally arranged as described above, and is a schematic plan view of the stent 20o viewed from a direction orthogonal to the central axis. As shown in FIG. 22, the stent 20o has a tubular structure 22o and markers 20o1 to 20o17. The markers 20o1 to 20o10 having the same dimensions are provided spirally from one end of the tubular structure 22o. The markers 20o11 to 20o17 have the same dimensions as each other but are larger than the markers 20o1 to 20o10, and are provided spirally from the other end of the tubular structure 22o.

  Like the markers 20o1 to 20o10, there are three folds on the marker array in the Y-axis direction, and if there are three markers before the fold, the arrangement of the markers 20o1 to 20o10 is recognized as a spiral in the X-ray image. sell. However, when there are only two folds on the marker array in the Y-axis direction, that is, in the case of only the markers 20o1 to 20o7, the locus of the marker appears to be a triangle, so it is difficult to recognize the spiral arrangement. In addition, even if there are three folds on the marker array in the Y-axis direction, if there are only two markers until the folds, such as markers 20o11 to 20o17, the number of markers is small, so a spiral or polygon It is difficult to recognize.

  Therefore, in order to recognize the spiral arrangement in the X-ray image, there are 10 or more markers such as (number of markers until folding) 3 (folding 3 times) +1, as in markers 20o1 to 20o10. desirable. More preferably, it is preferable that 20 or more markers that are twice as many are arranged in a spiral. More desirably, as in the embodiment of FIG. 21, it is desirable that 40 or more markers, which are four times as many, are spirally arranged. In addition, as an upper limit of the number of markers, it is desirable that the interval between markers can be identified even when the image size in the X-ray diagnostic apparatus is large.

(Eleventh embodiment)
FIG. 23 is a schematic plan view showing the configuration of the stent 20p in the stent system of the eleventh embodiment. As shown in FIG. 11, the stent 20p has a tubular structure 22p, radiopaque markers 24p1 to 24p15, and a patch 30p. This embodiment is a combination of the configurations of the first to sixth, eighth, and ninth embodiments, and the material of the tubular structure 22p, the position and material of the patch 30p, and the like are the same as those of the above embodiment. A duplicate description is omitted.

  In the present embodiment, as an example, there are four types of marker shapes and sizes, and the markers 24p1 and 24p2, the markers 24p3 to 24p7, the markers 24p8 to 24p13, and the markers 24p14 and 24p15 are different from each other.

  The markers 24p1 and 24p2 have the same size, shape, dimensions, and X-ray transmittance (for example, a cube having a side of 220 μm), and are provided on one end side of the tubular structure 22p. The markers 24p3 to 24p15 have the same X-ray transmittance, but the X-ray transmittances of the markers 24p1 and 24p2 are, for example, 50% of the markers 24p3 to 24p15. The marker 24p7 is provided on the other end side of the tubular structure 22p. Therefore, the one end side and the other end side can be distinguished by the difference in size, number, shape, and X-ray transmittance between the markers 24p1, 24p2 on one end side of the tubular structure 22p and the marker 24p7 on the other end side. The same effects as those of the first to fourth embodiments can be obtained.

  The markers 24p3 to 24p7 have the same size, shape, dimensions, and X-ray transmittance (for example, a regular tetrahedron having a side of 120 μm), and include the marker 24p2 and are arranged on a straight line in the central axis direction of the tubular structure 22p. They are provided at equal intervals (the interval between the centers of the markers is, for example, 5 millimeters). Therefore, regardless of the X-ray irradiation direction, the length of the stent 20p in the X-ray image can be determined from the number of markers, and the same effect as in the sixth embodiment can be obtained.

  The markers 24p8 to 24p13 have the same size, shape, dimension, and X-ray transmittance (for example, a sphere having a side of 80 μm). Similar to the ninth embodiment, the markers 24p8 to 24p13 are spaced apart from each other at equal intervals on a cross section parallel to the diameter of the tubular structure 22m at an intermediate position between the markers 24p2 and 24p7 at both ends. ing. Therefore, the same effect as in the ninth embodiment can be obtained.

  Further, when the stent 20p is bent, the degree of bending of the stent 20p can be determined from the positional relationship between the markers 24p2 and 24p7 at both ends and the markers 24p3 to 24p6, and the same effect as the fifth embodiment can be obtained. .

  The markers 24p14 and 24p15 have the same size, shape, dimensions, and X-ray transmittance (for example, a rectangular parallelepiped shape of 180 μm × 100 μm × 100 μm), and are provided on the patch 30p at positions facing each other with the marker 24p13 interposed therebetween. It has been. Although the stent 20p has an asymmetric structure by having the patch 30p, the position of the patch can be specified by identifying the side where the markers 24p14 and 24p15 are present in the X-ray image. That is, the same effect as in the eighth embodiment can be obtained.

(Twelfth embodiment)
The twelfth embodiment relates to an X-ray diagnostic apparatus. In the twelfth embodiment, X-rays are radiated to a treatment site of a subject in which a plurality of stents capable of distinguishing one end side and the other end side described in the above-mentioned embodiment are placed in the body, and the X-rays are in time series. Each stent is accurately detected by generating an image and applying image processing described later to these X-ray images. This makes it possible to accurately set the region of interest and track each stent. An example of the use is a check operation of each stent by a doctor during intravascular intervention treatment.

  FIG. 24 is a functional block diagram showing the configuration of the X-ray diagnostic apparatus 60 in the twelfth embodiment. As shown in FIG. 12, the X-ray diagnostic apparatus 60 includes a high voltage generator 62, an X-ray tube 64, an X-ray diaphragm device 66, a diaphragm controller 68, and a top plate on which the subject P is placed. 70, a top plate moving mechanism 72, a C arm 74, a C arm rotation moving mechanism 76, a C arm top plate control unit 78, an X-ray detector 80, an image data generation unit 82, and an image data storage unit. 84, an image processing unit 86, a display unit 88, an input unit 90, and a system control unit 92.

  The high voltage generator 62 generates a high voltage and supplies the generated high voltage to the X-ray tube 64. The X-ray tube 64 generates X-rays using the high voltage supplied from the high voltage generator 62. That is, the high voltage generator 62 adjusts the voltage supplied to the X-ray tube 64 to adjust the X-ray dose irradiated to the subject P and turn on / off the X-ray irradiation to the subject P. Control.

  The X-ray diaphragm device 66 narrows the X-ray generated by the X-ray tube 64 so as to selectively irradiate the region of interest (ROI: Region of Interest) of the subject P. The X-ray diaphragm device 66 has, for example, a plurality of slidable diaphragm blades (not shown). By sliding these diaphragm blades, the X-rays generated by the X-ray tube 64 are narrowed and irradiated onto the subject P. Let The aperture control unit 68 controls the X-ray irradiation range by adjusting the aperture of the aperture blades of the X-ray aperture device 66.

  The X-ray detector 80 is an apparatus in which X-ray detection elements (not shown) for detecting X-rays transmitted through the subject P are arranged in a matrix, and each X-ray detection element is connected to the subject P. X-rays transmitted through are converted into electrical signals and stored, and the stored electrical signals are input to the image data generation unit 82.

  The C arm 74 is an arm that holds the X-ray tube 64, the X-ray diaphragm device 66, and the X-ray detector 80. By the C arm 74, the X-ray tube 64, the X-ray diaphragm device 66, and the X-ray detector 80 are arranged to face each other with the subject P interposed therebetween. The top board 70 is a bed on which the subject P is placed, and is placed on a bed (not shown).

  The top plate moving mechanism 72 is a device that moves the top plate 70, and the C arm rotation moving mechanism 76 is a device that rotates and moves the C arm 74. The C-arm top plate control unit 78 controls the C-arm rotation / movement mechanism 76 and the top-plate movement mechanism 72 to perform rotation adjustment and movement adjustment of the C-arm 74 and movement adjustment of the top plate 70.

  The image data generation unit 82 generates image data of an X-ray image using an electrical signal converted from an X-ray transmitted through the subject P by the X-ray detector 80, and the generated image data of the X-ray image is converted into an image. The data is input to the data storage unit 84. Specifically, the image data generation unit 82 performs current / voltage conversion, A / D conversion, and parallel-serial conversion on the electrical signal received from the X-ray detector 80 to generate image data of the X-ray image. Generate. The image data storage unit 84 stores the image data of the X-ray image generated by the image data generation unit 82.

  The image processing unit 86 includes a stent detection unit 86a, a correction image generation unit 86b, and an image post-processing unit 86c, and performs various types of image processing on the image data of the X-ray image stored in the image data storage unit 84. Execute. Details of this will be described later.

  The input unit 90 includes a mouse, a keyboard, a button, a trackball, a joystick, and the like for an operator who operates the X-ray diagnostic apparatus 60 to input various commands. The data is transferred to the unit 92.

  The display unit 88 displays a GUI (Graphical User Interface) for receiving a command from the operator via the input unit 90, and the X-ray image stored in the image data storage unit 84 and the image processing unit 86 A monitor (not shown) that displays an image-processed X-ray image or the like is included.

  The system control unit 92 controls the entire X-ray diagnostic apparatus 60. That is, the system control unit 92 controls the high voltage generator 62, the C-arm top panel control unit 78, and the aperture control unit 68 based on the operator command transferred from the input unit 90, so that the X-ray dose is controlled. Adjustment and X-ray irradiation on / off control, adjustment of rotational movement of the C arm 74, and adjustment of movement of the top board 70 are performed. The system control unit 92 controls image generation processing in the image data generation unit 82 and image processing in the image processing unit 86 based on an operator command. Further, the system control unit 92 controls to display the image data of the X-ray image on the monitor of the display unit 88 as an image.

Next, a marker position detection method for each stent will be described with reference to FIGS.
FIG. 25 is an explanatory diagram illustrating an example of a marker position detection method for each stent, and is a schematic diagram illustrating an example of an X-ray image of a subject P in which two stents 20a according to the first embodiment are placed in the body. It is.

  First, every time image data of a new X-ray image is stored in the image data storage unit 84, the stent detection unit 86a of the image processing unit 86 detects the positions of all markers in the X-ray image. The marker (24α or the like) of each of the above embodiments has a much higher X-ray absorption rate than a stent tubular structure formed of an X-ray transparent material, a human blood vessel, or fat. Therefore, the marker can be identified as a pixel region darker than the surroundings in the X-ray image of the X-ray transmitted through the human body. That is, by performing threshold processing on the CT value or pixel value of each pixel (for example, a value representing the luminance of a pixel expressed with the black level being zero and the white level being maximized), a pixel region whose luminance is less than a certain level is used as a marker It can be detected.

  As for the position of the marker, for example, all the pixels of the X-ray image may be represented by two-dimensional coordinates and the position of the marker may be represented by the coordinates of the pixels corresponding to the marker. For example, the horizontal direction of the image may be represented as the X-axis direction, the vertical direction of the image may be represented as the Y-axis direction, and the pixel at the lower left vertex of the image may be represented as the origin (0, 0) of the X, Y coordinate system.

  Next, the stent detector 86a determines the number of stents and the position for each stent based on the detected positions of the plurality of markers. Specifically, the stent detection unit 86a identifies the size of the marker based on the number of pixels corresponding to the marker.

  For example, when the X-ray image shown in FIG. 25A is obtained, the stent detection unit 86a detects the coordinate positions of the four markers 24x1 to 24x4, and then the markers 24x1 and 24x3 are small and the markers 24x2 and 24x4 are large. Is determined. Here, prior information regarding the marker of each stent is set in advance to the stent detection unit 86a (via the system control unit 92) by an input to the input unit 90. “Preliminary information on markers” means, for example, “Each stent has one marker at each end, and the markers at both ends of each stent differ in size, shape, and / or X-ray transmittance”. is there. Based on this prior information, the stent detector 86a determines that the marker belonging to the same stent as the marker 24x1 is one of the markers 24x2 and 24x4.

Next, when the stent detection unit 86a determines that one stent is used for the markers 24x1 and 24x2 as shown in FIG. 25B, and when one stent is used for the markers 24x1 and 24x4 as shown in FIG. 25C. Whether or not the following “determination condition” is satisfied is determined.
That is, what is determined as one stent is that the stent length is not longer than, for example, 1.6 times or more than the other stents. In this case, if the marker 24x1, 24x4 is determined to be one stent, the marker 24x2 and the marker 24x3 are determined to be another one stent. However, what is determined as one stent is 1.6 times that of the other stents. It becomes the above length. Therefore, the stent detection unit 86a determines that the marker 24x1, 24x4 is not one stent.

  The stent detection unit 86a determines that one marker is used for the markers 24x1 and 24x2 and another one stent is used for the markers 24x3 and 24x4 by the erasing method as described above. The above determination condition is an example, and other numerical values may be used instead of 1.6 times. Instead of this determination condition, for example, a condition that “the one determined as a stent does not include the entire other stent” may be used.

  FIG. 26 is an explanatory diagram showing another example of a method for detecting a marker position for each stent, and shows an example of an X-ray image of a subject P in which three stents 20a of the first embodiment are placed in the body. It is a schematic diagram. In this case, as described above, the stent detection unit 86a detects the positions of all the markers 24x5 to 24x10 by threshold processing, for example, and the markers 24x5, 24x7, and 24x9 are small and the markers 24x6, 24x8, and 24x10 depending on the number of pixels of each marker. Is determined to be large.

  For example, when the X-ray image shown in FIG. 26A is obtained, one of the markers 24x6, 24x8, and 24x10 belongs to the same stent as the marker 24x5 based on the above-described "preliminary information on the marker". Then, the stent detection unit 86a determines.

  Next, the stent detector 86a determines that one stent is determined by the markers 24x5 and 24x6 (see FIG. 26B), and determines that one stent is determined by the markers 24x5 and 24x8 (see FIG. 26C). Whether or not one stent is determined by the marker 24x5 and the marker 24x10 determines whether or not the above-described determination condition is satisfied.

  In this case, except for the case where one marker is determined by the markers 24x5 and 24x6, the combination of the small marker (24x5, 24x7, 24x9) and the large marker (24x6, 24x8, 24x10) can be used in the case of FIG. Does not meet the same criteria. In this way, the stent detector 86a confirms all combinations of small markers and large markers. As a result, the stent detection unit 86a satisfies the determination condition only in the case of one stent for the markers 24x5 and 24x6, one stent for the markers 24x7 and 24x8, and one stent for the markers 24x9 and 24x10 as shown in FIG. Is determined.

  FIG. 27 is an explanatory diagram showing another example of a method for detecting a marker position for each stent, and shows an example of an X-ray image of a subject P in which two stents 20e of the third embodiment are placed in the body. It is a schematic diagram. In this case, the stent detector 86a detects the positions of all the markers 24y1 to 24y4 in the same manner as described above, and the markers 24y1 and 24y3 are cross-shaped from the pixel area of each marker based on the “preliminary information on the marker”. It is determined that 24y2 and 24y4 are squares. Thereby, the stent detection unit 86a determines that any of the markers 24y2 and 24y4 belongs to the same stent as the marker 24y1.

  Next, the stent detection unit 86a determines that one stent is determined by the markers 24y1 and 24y2 (see FIG. 27B), and determines that one stent is determined by the markers 24y1 and 24y4 (see FIG. 27C). Then, it is determined whether or not the aforementioned determination condition is satisfied. Thereby, the stent detection unit 86a determines that the determination condition is satisfied only when one stent is set for the markers 24y1 and 24y2 and one stent is set for the markers 24y3 and 24y4 as shown in FIG.

  FIG. 28 is an explanatory view showing another example of the marker position detection method for each stent, and shows an example of an X-ray image of a subject P in which two stents 20f of the fourth embodiment are placed in the body. It is a schematic diagram. In this case, the stent detection unit 86a detects the positions of all the markers 24z1 to 24z4 in the same manner as described above, and the markers 24z1 and 24z3 are black based on the difference in luminance of the pixel areas of the markers based on the “preliminary information on the markers” It is determined that the markers 24z2 and 24z4 are gray. Here, “gray” means that the X-ray image is much darker than the surroundings, but has a higher luminance than other markers because the X-ray transmittance is relatively high as a marker. Similarly, “black” here means that the X-ray transmittance is relatively low as a marker, and therefore, the luminance is lower than other markers in the X-ray image.

  As the marker identification process based on the above “difference in luminance”, for example, apart from the (first) threshold value used in the threshold process for detecting the positions of all the markers, the difference in X-ray transmittance for each marker is used. What is necessary is just to set the 2nd threshold value to identify. In this case, if the average value of the pixel values is obtained for each image area of each marker, the average value of the pixel values is divided into a marker having an average value of the pixel value equal to or greater than the second threshold value, and a marker having an average pixel value of less than the second threshold value. Good. Based on the above processing result and the above-described “preliminary information on the marker”, the stent detection unit 86a determines that one of the markers 24z2 and 24z4 belongs to the same stent as the marker 24z1.

  Next, when the stent detector 86a determines that one stent is used for the markers 24z1 and 24z2 (see FIG. 28B), and when it is determined that one stent is used for the markers 24z1 and 24z4 (see FIG. 28C). Then, it is determined whether or not the aforementioned determination condition is satisfied. As a result, the stent detection unit 86a determines that the determination condition is satisfied only when one stent is used for the markers 24z1 and 24z2 and one stent is used for the markers 24z3 and 24z4 as shown in FIG.

  FIG. 29 is an explanatory diagram regarding marker prior information for detecting a marker position for each stent when two stents 20b according to the second embodiment are placed in the body. When an X-ray image as shown in FIG. 29 (A) is obtained, and codes 24b1, 24b2, 24b3, 24b1 ′, 24b2 ′, and 24b3 ′ are assigned to the detected markers as shown in FIG. 29 (A), It becomes difficult to determine which of the following states is true. That is, as shown in FIG. 29B, the markers 24b1, 24b2, and 24b3 are one stent, and the other markers are one stent. As shown in FIG. 29C, the markers 24b1, 24b2 ′, and 24b3 are used. It is difficult to judge whether it is 1 stent with 'other, and other stents.

  Here, during the stent insertion treatment, for example, a guide wire is inserted into the stent, so that the stent is not reversed in the stent insertion stage. Therefore, when two stents 20b of the second embodiment are inserted, for example, one marker is "the side far from the subject entrance" in the stent, and two markers are "the side near the subject entrance" in the stent. If the stent insertion process is advanced so that the X-ray image as shown in FIG. 29A is generated, it can be avoided.

  Therefore, for example, the following two points are set in advance from the input unit 90 to the stent detection unit 86a as “preliminary information on the marker”. First, each of the two stents has one marker on one end and two markers on the other end. Second, the two stents are both placed so that one marker is located on the side far from the entrance of the subject and two markers are located on the side near the entrance of the subject.

  FIG. 30 is a schematic plan view illustrating a marker position detection method for each stent in an X-ray image of a subject in which two stents 20b according to the second embodiment are placed in the body. When the X-ray image of FIG. 30A is obtained, the stent detector 86a detects the positions of all the markers 24b1, 24b2, 24b3, 24b1 ', 24b2', 24b3 'as described above.

  Next, the stent detector 86a determines that the stent arrangement giving the marker arrangement of FIG. 30A is any one of FIG. 30B, FIG. 30C, and FIG. This determination can be accurately processed by performing pattern matching so as to satisfy the “preliminary information on the marker” including the two points described above with reference to FIG. 29 and the determination conditions similar to those in FIG. .

  FIG. 30B shows a case where the markers 24b1, 24b2, and 24b3 are one stent and the other markers are one stent. FIG. 30C shows a case where one marker is used for the markers 24b1, 24b2, 24b1 'and one stent is used for the other markers. FIG. 30D shows a case where one marker is used for the markers 24b1, 24b1 'and 24b3 and one stent is used for the other markers.

  Here, in addition to the above two points, the ratio of the lengths of the following intervals W1 and W2 is set in advance from the input unit 90 to the stent detection unit 86a as “preliminary information on the marker”. That is, the length of the interval W1 from the marker 24b1 on one end side to the marker 24b2 (or 24b3) on the other end side and the interval W2 from the marker 24b2 on the other end side to the marker 24b3 in the stent 20b shown in FIG. Is the ratio. By setting this in advance, as described below, when the X-ray image of FIG. 30 (A) is obtained, the stent is in the state of FIG. 30 (B), FIG. 30 (C), It can be determined whether it is any of FIG.

  Specifically, the stent detection unit 86a obtains an interval W3 (for example, by the number of pixels) between the markers 24b2'-24b3 'in the X-ray image of FIG. Next, the stent detector 86a determines which of the two markers 24b2, 24b1 ′ and 24b3 arranged on the X-ray image in FIG. 30A belongs to one end of the same stent. Determination is made so as to be closest to the interval W3. In this example, as shown in FIG. 30B, by determining that the markers 24b2 and 24b3 belong to one end of the same stent, the interval between the markers 24b2 to 24b3 is closest to the interval W3 between the markers 24b2 ′ to 24b3 ′. Become. The stent detection unit 86a determines that the two stents are in the state of FIG. 30B from the X-ray image of FIG.

  Note that there is no problem even if it is erroneously recognized as being in the state of FIG. 30C or FIG. 30D despite being in the state of FIG. If one marker on one end of one stent and two markers on one end of the other stent are lined up at the same location in the blood vessel, the three markers will show the same movement at that location. Even if it is recognized, the latter stage is not affected when the stent is tracked.

Next, a method of selecting a stent to be tracked (hereinafter referred to as “tracking stent”) will be described.
FIG. 31 is a schematic diagram illustrating an example of an X-ray image displayed on the display unit 88 for selecting a tracking stent. The corrected image generation unit 86b generates and outputs image data of an X-ray image in which each stent and marker are identified and displayed based on the determination result of the stent detection unit 86a. The display unit 88 is based on the image data. Display. As shown in FIG. 31, here, as an example, a rectangular frame corresponding to each stent is superimposed on the X-ray image. Each rectangular frame is displayed to include all markers belonging to the same stent.

Hereinafter, the length and width of the rectangular frame will be described. It is desirable that the length and width of the rectangular frame be matched to the outline of the stent as much as possible.
First, the length of the rectangular frame will be described. For example, in the specification of the stent, when the marker interval between the one end side and the other end side is 8 mm and the stent length is 10 mm, the length of the rectangular frame may be 1.25 times the marker interval. That is, the stent specification information is acquired in advance, and the usage information is input to the correction image generation unit 86b via the system control unit 92 by an operation on the input unit 90, and the actual stent length and the length of the rectangular frame are input. Should be matched. In this example, since the marker interval is shorter than the stent length, a rectangular frame including a plurality of markers belonging to the same stent is displayed.
As another example, when the marker interval between the one end side and the other end side is 10 mm and the stent length is 10 mm, the length of the rectangular frame is set to 1.0 times the marker interval, The length of the rectangular frame may be matched. In this example, since the marker interval is equal to the stent length, a rectangular frame in which a plurality of markers belonging to the same stent overlap the outer edge is displayed.

Next, the width of the rectangular frame will be described.
As a first example, when the pixel area of the marker occupying the X-ray image can be substantially regarded as the width of the stent, as in the stent 20d described in FIG. 7, the actual stent area is determined based on the pixel area of the marker occupying the image. The width and the width of the rectangular frame may be matched.

  As a second example, when the width of the stent cannot be determined from the X-ray image, the width in the standard expansion state based on the specification of the stent may be set as the width of the rectangular frame. For example, in the case of a stent in which the marker interval between one end and the other end is 10 mm and the diameter at the time of standard expansion is 3.0 mm, 0.3 times the marker interval that can be recognized from the X-ray image is The width may be used.

As a third example, when the stent width cannot be determined from the X-ray image, the standard expansion state based on the stent specification and the length information per pixel of the X-ray image The width of the rectangular frame is determined so as to be as close as possible to the width in the expanded state. For example, when the size of one pixel of the X-ray image is 0.1 mm (vertical and horizontal) and the diameter at the time of standard expansion of the stent is 3.0 mm, the width of the rectangular frame is 3.0 ÷ 0. .1 = 30 pixels
Note that the length of one pixel corresponding to the actual length of the subject can be calculated based on the following two pieces of information. The first is distance information between the X-ray generation source and the X-ray detection element, and the second is the position at which the subject is located between the X-ray generation source and the X-ray detection element. Information.

  The input unit 90 and the display unit 88 are configured to select a tracking stent in a state where the X-ray image as described above is displayed on the display unit 88. For example, the tracking stent may be selected by the operator by moving the cursor by operating the mouse via the input unit 90. Alternatively, as shown in FIG. 31, “Stent1” and “Sent2” and numbers may be superimposed on an X-ray image for each detected stent, and a tracking stent may be selected by keyboard input. Alternatively, the monitor of the display unit 88 may be a touch panel type so that the tracking stent can be selected by touch input.

  Note that the number of tracking stents that can be selected is not limited to one, and the input unit 90 and the display unit 88 are configured to be able to select a plurality of stents. For example, during an endovascular interventional treatment, it is desirable to track two stents in an operation where the two stents are placed so that they overlap slightly at the ends.

  Next, a method for setting a region of interest will be described. When the tracking stent is selected, the input unit 90 and the display unit 88 are configured to be able to input and set a region of interest that will be a subsequent X-ray irradiation region. Here, as an example, when the region of interest setting is not input even after a predetermined time has elapsed since the tracking stent is selected, the system control unit 92 surely includes the tracking stent regardless of the movement of the subject P such as pulsation. Automatically set the appropriate region of interest.

  FIG. 32 is a schematic diagram illustrating an example of a region of interest that is automatically set by the system control unit 92 based on the X-ray image used for selecting the tracking stent. FIG. 32 is an example of a case where a region of interest is automatically set based on the X-ray image of FIG.

The region of interest in FIG. 32 can be used, for example, to assist in placing the two stents so that they overlap slightly at the ends during endovascular interventional treatment. Specifically, for example, when two stents are selected in FIG. 31, the system control unit 92 is displayed corresponding to each of the two stents as indicated by the dotted lines in FIG. 32 (solid lines in the figure). Determine the smallest rectangle that contains two rectangles. The method for determining the length and width of the rectangular frame displayed corresponding to each of the two stents is as described above.
Next, the system control unit 92 sets, as the region of interest, a region whose vertical and horizontal lengths are doubled around the dotted rectangle. The bold frame in the figure is an example of the region of interest that is automatically set in this way. Note that the region of interest is not limited to a rectangular region, and may be, for example, a circular region.

  FIG. 33 is a schematic diagram showing another example of a region of interest automatically set by the system control unit 92 based on the X-ray image used for selecting the tracking stent. FIG. 33 is also an example of the case where the region of interest is automatically set based on the X-ray image of FIG. 31. This case corresponds to the case where only “Sent 1” is selected in FIG.

Specifically, when “Sent1” is selected in FIG. 31, the system control unit 92 is displayed corresponding to “Sent1” as indicated by a dotted line in FIG. 33 (solid line in the figure). Determine the smallest rectangle that contains a rectangular frame.
Next, the system control unit 92 obtains the length of the longer side of the dotted rectangle. A square region whose length of one side is twice the length of the longer side of the dotted rectangle is set as a region of interest with the dotted rectangle as the center. The bold frame in the figure is an example of the region of interest that is automatically set in this way.

Regarding the setting of the region of interest, other images may be used instead of the X-ray image used for selecting the tracking stent as described above.
32 and 33, the horizontal direction and the vertical direction of the image with respect to the subject P are matched in the X-ray image used for selecting the tracking stent and the automatically set region of interest for simplification. The above is only an example, and by controlling the X-ray irradiation range, the region of interest may be automatically set so that the length direction of the stent matches the horizontal direction or the vertical direction of the image.

  In the present embodiment, after selecting the tracking stent and setting the region of interest, image data is sequentially generated by X-ray irradiation, and the tracking stent is identified in the sequentially generated image data. Here, as an example, a method of identifying a tracking stent using “relative position information” and “tracking marker information” described below will be described.

  When the tracking stent is selected, the stent detection unit 86a obtains and holds the relative position information of the tracking stent and other stents in the X-ray image used for selecting the tracking stent. This relative position information may be expressed by, for example, the top, bottom, left, and right of the image. When Stent1 is selected as the tracking stent in FIG. ".

  In addition, when two stents are selected as tracking stents, for example, information such as “one tracking stent is on the upper left side of the other tracking stent in the image” so that both can be recognized separately. Is generated. Note that the relative position information is not limited to the vertical and horizontal directions in the image, and may be in other forms as long as the positional relationship between the tracking stent and another stent can be defined.

  Furthermore, the stent detection unit 86a obtains and holds “tracking marker information” regarding the marker of the tracking stent using the X-ray image used for selection of the tracking stent. The tracking marker information includes at least the shape of the marker, the size of the marker, the brightness of the marker (corresponding to the X-ray transmittance), the number of markers on one end side, and the number of markers on the other end side. For example, when Stent1 is selected as the tracking stent in FIG. 31, there is one small circular marker on the right side (one end side) of the image and one large circular marker on the left side (the other end side) of the image, And the marker are information such as the same luminance.

  FIG. 34 is a schematic diagram showing a tracking stent identification method by the stent detector 86a. For example, when an X-ray image as shown in FIG. 34A is obtained and the markers 24y1 to 24y4 are detected, one stent and marker are used for the markers 24y1 and 24y2 by the same means as described with reference to FIG. One stent is determined at 24y3 and 24y4. Here, as the above relative position information, for example, if there is information such as “the tracking stent is on the upper right side of the image than the other stent”, as shown in FIG. 34 (B), FIG. It can be determined that the markers 24y3 and 24y4 in FIG.

  In the case of stents with different marker sizes at both ends, stents with different marker X-ray transmittance at both ends, and stents with different numbers of markers at both ends, tracking marker information and relative position information are also displayed as described above. Based on this, a tracking stent can be detected. The method for identifying the tracking stent marker from the plurality of markers shown in the X-ray image is not limited to the means using the relative position information and tracking marker information, and other means such as pattern matching may be used. It may be used.

  Next, a display example of an X-ray image after selecting a tracking stent will be described. The X-ray diagnostic apparatus 60 displays a moving image by sequentially displaying X-ray images sequentially generated after selection of the tracking stent in time series. Since there are many ways to display this moving image, several examples will be described below.

  FIG. 35 is a schematic diagram showing an example of a display image displayed as a moving image after selection of a tracking stent, and corresponds to a case where two stents are selected as tracking stents as shown in FIG. The correction image generation unit 86b has a rectangular solid line frame including all the markers belonging to one tracking stent based on both marker positions corresponding to one tracking stent detected by the stent detection unit 86a as shown in FIG. Similarly, image processing is performed on the image data of the X-ray image so as to be superimposed on the X-ray image.

  Further, the correction image generation unit 86b is configured to superimpose a rectangular dotted line frame including all markers belonging to the other tracking stent on the X-ray image based on both marker positions corresponding to the detected other tracking stent. Then, image processing is performed on the image data of the X-ray image. The solid and dotted rectangular frames are examples of stent identification display, and other forms of identification display may be used. For example, the rectangular region estimated as the region of each tracking stent may be displayed on the image by displaying the regions in different chromatic colors.

  Thus, in the image displayed as a moving image, the frames corresponding to the respective stents are distinguished and displayed in the image, whereby each stent can be individually tracked.

  FIG. 36 is a schematic diagram showing another example of a display image displayed as a moving image after selection of the tracking stent, and corresponds to a case where one stent is selected as the tracking stent as shown in FIG. Similarly, in this case, the correction image generation unit 86b also converts, for example, a rectangular solid line frame including a marker belonging to the tracking stent into an X-ray image based on the marker position corresponding to the tracking stent identified by the stent detection unit 86a. The image data is corrected so as to be superimposed.

  When there is one tracking stent, for example, a correction image may be generated so that the tracking stent is always positioned in the center of the display image with the same size and orientation, and the correction image may be sequentially displayed. The process in this case will be briefly described. The corrected image generation unit 86b uses the coordinates of the marker of the tracking stent detected by the marker coordinate detection unit 86a in the first generated X-ray image (first frame) as the reference coordinates. To do.

Next, the corrected image generation unit 86b generates a new image after the second frame so that the coordinates of the marker of the tracking stent detected by the marker coordinate detection unit 86a in the new image after the second frame coincide with the reference coordinates. The corrected image is generated by performing image movement processing such as parallel movement and rotational movement and image deformation processing such as affine transformation.
Thereafter, the correction image generation unit 26b similarly generates a correction image for the new image after the third frame, using the coordinates of the stent marker in the X-ray image generated immediately before the new image as reference coordinates.

  FIG. 37 is a flowchart showing the operation of the X-ray diagnostic apparatus 60 of the present embodiment. Hereinafter, the operation of the X-ray diagnostic apparatus 60 will be described according to the step numbers shown in FIG. 37 with reference to FIGS.

[Step S1] The system control unit 92 (see FIG. 24), based on the input information input via the input unit 90, the imaging region (for the subject P including a plurality of stents), tube current, tube voltage, Initial setting of imaging conditions such as X-ray pulse width is performed.
Further, the operator can set the above-described “preliminary information on the marker” to the system control unit 92 by an input to the input unit 90. The system control unit 92 transmits the set “prior information about the marker” to the stent detection unit 86a. Thereafter, the process proceeds to step S2.

  [Step S2] According to the control of the system control unit 92, the high voltage generator 62 supplies a high voltage to the X-ray tube 64, and the X-ray tube 64 generates X-rays. The X-ray irradiation range is controlled. The X-ray detector 80 detects X-rays that have passed through the subject P, converts them into electrical signals, and inputs them to the image data generation unit 82. The image data generation unit 82 generates image data of an X-ray image from the input electrical signal, and stores it in the image data storage unit 84. Thereafter, the process proceeds to step S3.

  [Step S3] The stent detection unit 86a acquires the image data generated in step S2 from the image data storage unit 84. The stent detector 86a detects the pixel area of the radiopaque marker from the image data by threshold processing for the pixel value, for example. Thereafter, the process proceeds to step S4.

  [Step S4] The stent detector 86a determines how many stents exist and which stent each marker belongs to based on the plurality of markers detected in step S3 for one X-ray image. This determination includes at least a difference in size between markers, a difference in shape between markers, a difference in X-ray transmittance between markers, and a number difference between the number of markers on one end and the number of markers on the other end of the stent. This is performed based on either one (see FIGS. 25 to 30). If advance information regarding the marker is set in step S1, this information is also used in this determination. Thereafter, the process proceeds to step S5.

[Step S5] Based on the determination result of the stent detection unit 86a, the corrected image generation unit 86b, for example, superimposes a rectangular frame corresponding to each stent, or the like, and image data of an X-ray image that identifies and displays each stent. Is input to the image post-processing unit 86c.
The image post-processing unit 86 c performs post-processing on the input image data, and then inputs this to the display unit 88. The post-processing here is, for example, high-frequency noise reduction processing using a recursive filter or low-frequency component removal processing using a high-pass filter. The display unit 88 displays the input image data as an image for selecting a tracking stent (see FIG. 31). Thereafter, the process proceeds to step S6.

  [Step S6] In the state where the X-ray image in which each stent is identified and displayed is displayed on the display unit 88, the input unit 90 and the display unit 88 stand by until an input for selecting a tracking stent is performed. If a tracking stent is not selected even after a predetermined time has elapsed from the start of displaying the X-ray image identifying each stent, the system control unit 92 returns to step S1 and regenerates the image data of the X-ray image. Let

  When the tracking stent is selected, the stent detection unit 86a obtains and holds the relative position information of the tracking stent and the other stent and the tracking marker information. The reference for obtaining the relative position information and the tracking marker information is an X-ray image used for selection of the tracking stent as an example here, but is not limited to this. For example, an X-ray image taken after selection of the tracking stent is used as a reference. You may ask for. Thereafter, the process proceeds to step S7.

  [Step S7] After the selection of the tracking stent in step S6, when an input for setting the region of interest is performed by the operator on the input unit 90 or the display unit 88, the system control unit 92 determines the region of interest according to the input information. Set. If the region of interest is not set even after a predetermined time has elapsed since the tracking stent was selected, the system control unit 92 automatically sets the region of interest including the tracking stent (see FIGS. 32 and 33). Thereafter, the process proceeds to step S8.

  [Step S8] Under the control of the system control unit 92, the X-ray irradiation and image data generation for the region of interest are sequentially performed in time series as in steps S1 and S2. As a result, image data of the X-ray image is sequentially generated by the image data generation unit 82 and stored in the image data storage unit 84.

  The stent detection unit 86a acquires the image data generated in step S8 from the image data storage unit 84, detects all the markers in the image data, and which of the detected markers corresponds to the tracking stent. Determine. In this determination, as described above with reference to FIG. 34, the above-described relative position information and tracking marker information are used.

  The stent detection unit 86a performs recognition processing of the marker corresponding to the tracking stent described above on each of the sequentially generated image data, and sequentially inputs the recognition result together with the image data to the correction image generation unit 86b. The corrected image generation unit 86b performs image processing on the sequentially input image data so that the tracking stent (the marker in the tracking stent) is identified and displayed based on the recognition result of the stent detection unit 86a. The subsequent image data is sequentially input to the image post-processing unit 86c.

  The image post-processing unit 86 c performs post-processing such as high-frequency noise reduction processing and low-frequency component removal processing on the input image data, and then inputs this to the display unit 88. The display unit 88 sequentially displays the image data sequentially input in time series, that is, the image data of the X-ray image in which the tracking stent is identified and displayed as shown in FIGS. To do. The above is the description of the operation of the present embodiment.

  As described above, in this embodiment, an X-ray image of a subject P including a plurality of stents each provided with markers having different sizes, shapes, or X-ray transmittances, or a plurality of stents having different numbers of markers at both ends. , Each marker is recognized by distinguishing the mode. This effect will be described from the following first to third viewpoints.

  First, as a technique for improving the visibility of a moving stent, stent markers are extracted from a plurality of images, and image deformation is performed so that the marker positions are the same between the images. A technique for averaging is known. This technique does not hold if the X-ray images for a plurality of conventional X-ray transparent stents are aligned with the wrong marker combination.

  Specifically, when the X-ray image shown in FIG. 38 (A) is obtained, it is originally one stent for the markers 100a and 100b and another stent for the markers 100c and 100d as shown in FIG. 38 (B). Nevertheless, the markers 100a and 100c may be traced as one stent as shown in FIG. In some X-ray images, the markers 100a and 100c are detected as markers for one stent, while in the subsequent X-ray images, the markers 100a and 100b may be detected as markers for one stent. Such misrecognition of the marker causes image blur and image quality deterioration. On the other hand, in this embodiment, it is possible to accurately determine to which stent each marker belongs by recognizing the marker by distinguishing the state with respect to a stent in which markers having different states are arranged at both ends. Therefore, according to the present embodiment, the above-described conventional problems are solved, and alignment can be performed without making a mistake in the stent.

  Secondly, in order to reduce the exposure dose, it is desirable to reduce the X-ray irradiation amount as much as possible within a range where an appropriate image contrast can be obtained. The signal level difference between the gap between the body and the dark part is large, and it is difficult to identify each part in the body on the X-ray image. Therefore, there is a concept of optimizing the shooting conditions based on the region of interest. This is to monitor the X-ray luminance in a predetermined area and adjust the X-ray dose so that the luminance falls within an appropriate range. Further, an idea has been proposed in which the amount of movement of the stent is detected and the tube current, tube voltage, X-ray pulse width, etc. are changed according to the amount of movement.

  However, in the conventional polymer stent, as described above with reference to FIG. 38, there is a possibility that the wrong marker combination is detected as one stent, and the stent to be tracked cannot be identified on the X-ray image. Since the region of interest is set based on the position of the stent to be tracked on the X-ray image, if the stent to be tracked cannot be accurately identified on the X-ray image as in the prior art, it is a premise for optimization of imaging conditions. The region of interest may be set in the wrong region. On the other hand, in the present embodiment, it is possible to accurately determine the number of stents and the positions of both ends of each stent, so that the region of interest can be set appropriately. Therefore, since the imaging conditions can be optimized based on the region of interest set appropriately, the conventional problem is solved.

  Thirdly, there is a technique (region-of-interest fluoroscopy) that irradiates only a predetermined region (region of interest) with X-rays. When determining this region of interest, there is a method of defining a region around a marker detected from an X-ray image as a region of interest. Proposed.

  Here, for example, when focusing on a blood vessel with a heart, it is shortened in accordance with the size of the heart by bending in the systole of the pulsation of the heart, but in the diastole, the degree of bending is reduced. And the way of bending also changes in the length direction of the blood vessel on one side and the other side. When tracking a plurality of stents in such a blood vessel, it is desirable to accurately determine how many stents are present and where the markers on both ends of each stent are located.

  For example, when the X-ray image shown in FIG. 39A is obtained, the conventional technique cannot distinguish both ends of the stent, so there is a possibility that the region of interest may be set by mistake. Specifically, for example, a dotted rectangular frame is used although the markers 100a and 100b are one stent and the markers 100c and 100d are another stent like the solid rectangular frame shown in FIG. As described above, the markers 100a and 100c may be recognized as one stent, and the markers 100b and 104d may be recognized as another stent. In this case, as a result of tracking the markers 100a and 100c by mistake, the region of interest is set around the middle point of the markers 100a and 100c as shown by the thick frame in FIG.

  On the other hand, in the present embodiment, a stent in which markers having different states at both ends are arranged, or a stent having different numbers of markers at both ends, is targeted, and thus an X-ray image as shown in FIG. 39A is not obtained. For this reason, it is possible to accurately determine which stent each marker belongs to based on a difference in the state of the markers at both ends or a difference in the number of markers. Therefore, for example, as shown in FIG. 39C, it is possible to discriminate one stent by the markers 24x1, 24x2 and one stent by the markers 24x3, 24x4 from the difference in size. For this reason, as shown by a thick line frame in FIG. 39C, the region of interest can be appropriately set, and the stent can be accurately tracked. That is, in the X-ray diagnostic apparatus 60 of the present embodiment, the technique of irradiating only the region of interest with X-rays can be applied without hindrance.

(Supplementary matter of the present invention)
In the first to eleventh embodiments, examples of stents in which the tubular structure has a mesh shape (mesh shape) have been described. The embodiment of the present invention is not limited to such an aspect. For example, the present invention can be applied to a coiled stent.

  In the first to eleventh embodiments, the example of the balloon expandable type is described as the stent. The embodiment of the present invention is not limited to such an aspect. The stent may be of other types, for example self-expanding.

In the twelfth embodiment, using FIGS. 25 to 31, the difference in size between markers, the difference in shape between markers, the difference in X-ray transmittance between markers, the number of markers on one end side, and the other end side An example has been described in which the stent to which each marker belongs is identified based on either the number difference from the number of markers. The embodiment of the present invention is not limited to such an aspect.
(1) Difference in size between markers, (2) Difference in shape between markers, (3) Difference in X-ray transmittance between markers, (4) Number of markers on one end side and number of markers on the other end side The stent to which each marker belongs may be identified based on all four points of the number difference.
Alternatively, the stent to which each marker belongs may be identified based on any three or two of these four points. Similarly, when a tracking stent marker is identified from a plurality of markers detected in an X-ray image, all of the four points may be used, or any three or two points of the four points may be used. Good.

Finally, the correspondence between the terms of the claims and the embodiments will be described. In addition, the correspondence shown below is only one interpretation shown for reference, and does not limit the present invention.
The X-ray detector 80 is an example of an X-ray detector according to the claims.

  The function of the stent detection unit 86a that detects, as a marker, a pixel region in which a difference in contrast with the surroundings is a predetermined value by threshold processing on the pixel value is an example of a marker detection unit according to claims.

Based on at least one of size difference between markers, shape difference between markers, difference in X-ray transmittance between markers, difference in the number of markers on one end of the stent and the number of markers on the other end The function of the stent detector 86a that identifies the stent to which each marker belongs is an example of an identification processor described in the claims.
All markers in the tracking stent are an example of the tracking marker group described in the claims.

  The function of the display unit 88 for identifying and displaying each stent and the function of the input unit 90 to the display unit 88 for determining the stent selected by input as the tracking stent are examples of the selection unit described in the claims.

  The function of the system control unit 92 that sets the region of interest so that the region including the tracking stent becomes the region of interest is an example of the region-of-interest setting unit described in the claims.

8 Stent System 10 Catheter 12 Tube 14 Guide Wire 16 Balloons 18a, 18b Markers 20a-20p Stents 22a-22p Tubular Structures 24α, 24β, 24b, 24c1, 24c2, 24d1, 24d2 Markers 24e1, 24e2, 24g1-24g3, 24h1 To 24h6 Markers 24i1 to 24i3, 24j1 to 24j3, 24k1 to 24k6 Markers 24l1 to 24l3, 24m1 to 24m8, 24n, 24o1 to 24o17 Markers 24p1 to 24p15, 24x1 to 24x10, 24y1 to 24y4 Markers 24z1 to 24z4 Markers 26i, 26j, 26k Bifurcation unit 30, 30p Patch 40 Stent 42 Marker 60 X-ray diagnostic device 62 High voltage generator 64 X-ray tube 66 X-ray diaphragm device 68 Diaphragm control unit 70 Top plate 72 Top Moving mechanism 74 C arm 76 C arm rotation moving mechanism 78 C arm top plate control unit 80 X-ray detector 82 Image data generation unit 84 Image data storage unit 86 Image processing unit 86a Stent detection unit 86b Correction image generation unit 86c Image post-processing Unit 88 display unit 90 input unit 92 system control unit 100a to 100d marker

Claims (18)

A stent having a tubular structure that is formed by an X-ray transmissive material so as to be able to expand in diameter and in which a gap is formed,
A first marker formed of a radiopaque material and provided on the one end side of the tubular structure;
And a second marker that is formed of a radiopaque material and is provided on the other end side of the tubular structure and has a size larger than that of the first marker. The stent of claim 1,
Between the first and second markers in the tubular structure, the distance between the markers including the first and second markers is substantially equal, and is made of a radiopaque material. The stent further comprising at least one third marker formed. The stent of claim 1,
It is made of a radiopaque material, and further includes at least three third markers provided so as to be separated from each other so as to make one round of a cross section parallel to the diameter direction of the tubular structure. A stent characterized by that. The stent of claim 1,
As a part of the tubular structure, a branch portion branched in a branch shape from the middle of the tubular structure,
A stent comprising: a third marker formed of a radiopaque material and provided at a branch portion of the tubular structure. The stent of claim 1,
The tubular structure has a patch provided so as to partially close the gap,
A stent made of a radiopaque material and further comprising a third marker provided on or adjacent to the patch. A stent having a tubular structure that is formed by an X-ray transmissive material so as to be able to expand in diameter and in which a gap is formed,
A first marker formed of a radiopaque material and provided on the one end side of the tubular structure;
A second marker that is formed of a radiopaque material and is provided on the other end side of the tubular structure, and having a width different from that of the first marker and having a width of 40 μm or more. A stent characterized by A stent having a tubular structure that is formed by an X-ray transmissive material so as to be able to expand in diameter and in which a gap is formed,
At least one first marker formed of a radiopaque material and provided on the one end side of the tubular structure;
A plurality of second markers that are formed of a radiopaque material and are provided on the other end side of the tubular structure and are larger in number than the first markers. Stent. A stent having a tubular structure that is formed by an X-ray transmissive material so as to be able to expand in diameter and in which a gap is formed,
A first marker and a second marker provided on the one end side and the other end side of the tubular structure, respectively, formed of a radiopaque material,
The CT value is determined so that water is 0 and human tissue is 1000, and when imaged by an X-ray diagnostic apparatus under a tube voltage of 100 kilovolts, the CT value of the pixel region corresponding to the first marker; The stent according to claim 1, wherein the first and second markers have different X-ray transmittances so that a CT value of a pixel region corresponding to the second marker differs by 10 or more. A stent having a tubular structure that is formed by an X-ray transmissive material so as to be able to expand in diameter and in which a gap is formed,
A first marker formed of a radiopaque material and provided on the one end side of the tubular structure;
A second marker formed of a radiopaque material and provided on the other end side of the tubular structure;
The radiopaque material is provided so that the distance between the markers including the first and second markers is substantially equal between the first and second markers in the tubular structure. A stent comprising: at least one third marker formed by: A stent having a tubular structure that is formed by an X-ray transmissive material so as to be able to expand in diameter and in which a gap is formed,
As a part of the tubular structure, a branch portion branched in a branch shape from the middle of the tubular structure,
A first marker formed of a radiopaque material and provided on the one end side of the tubular structure;
A second marker formed of a radiopaque material and provided on the other end side of the tubular structure;
A stent comprising: a third marker formed of a radiopaque material and provided at a branch portion of the tubular structure. A stent having a tubular structure that is formed by an X-ray transmissive material so as to be able to expand in diameter and in which a gap is formed,
It is made of a radiopaque material, and has at least three markers provided so as to be separated from each other so as to make one round of a cross section parallel to the diametrical direction of the tubular structure. And stent. A stent having a tubular structure that is formed by an X-ray transmissive material so as to be able to expand in diameter and in which a gap is formed,
At least 10 pieces that are made of a radiopaque material and are spaced apart from each other at positions along a spiral trajectory from the one end side to the multi-end side of the tubular structure. A stent comprising a marker. A plurality of X-ray detection elements detect X-rays that have X-ray impermeable markers on one end side and the other end side and pass through a subject including a plurality of X-ray transmissive stents other than the markers. An X-ray detection unit that outputs an electrical signal corresponding to the X-ray dose for each X-ray detection element;
An image data generation unit that generates image data of an X-ray image of the subject so that the luminance of each pixel becomes a luminance according to an electric signal for each X-ray detection element;
In the image data, a marker detection unit that detects, as the marker, a pixel region in which a difference in contrast with the surroundings is a predetermined value because the X-ray dose detected by the X-ray detection element is less than the surroundings,
When four or more markers are detected in the image data of one X-ray image, the size difference between the markers, the shape difference between the markers, the X-ray transmittance between the markers And an identification processing unit for identifying the stent to which each marker belongs based on at least one of the number difference between the number of markers on the one end side and the number of markers on the other end side. X-ray diagnostic equipment. The X-ray diagnostic apparatus according to claim 13,
An X-ray diagnostic apparatus further comprising a display unit that identifies and displays a plurality of the markers separately for each of the stents belonging to the X-ray image indicated by the image data. The X-ray diagnostic apparatus according to claim 14,
The X-ray diagnosis apparatus, wherein the display unit displays a frame in which a plurality of the markers belonging to the same stent are included inside or overlapped with an outer edge as a frame corresponding to each of the stents. The X-ray diagnostic apparatus according to claim 14,
A selection unit that performs a selection process of selecting all the markers belonging to any of the stents as a tracking marker group based on input information corresponding to the plurality of markers identified and displayed for each stent in the display unit; ,
A region-of-interest setting unit configured to set a region including the tracking marker group as a region of interest serving as a reference of the X-ray irradiation region. The X-ray diagnostic apparatus according to claim 14,
A selection unit that performs a selection process of selecting all the markers belonging to any of the stents as a tracking marker group based on input information corresponding to the plurality of markers identified and displayed for each of the stents in the display unit; In addition,
The image data generation unit sequentially generates a plurality of the image data for the subject in time series after the selection process,
The marker detection unit sequentially performs a process of detecting a pixel area of the marker for each of the plurality of image data sequentially generated after the selection process,
In the tracking marker group, the identification processing unit includes a difference in size between the markers, a difference in shape between the markers, a difference in X-ray transmittance between the markers, the number of markers on one end side, and the other end Information of at least one of the difference in number from the number of markers on the side is acquired, and based on the acquired information, from the plurality of markers detected in the image data generated after the selection process, the tracking marker group Are sequentially processed to identify and transmit to the display unit,
The display unit sequentially displays the X-ray images indicated by the image data generated after the selection process in time series, and identifies and displays the tracking marker group in the sequentially displayed X-ray images. A characteristic X-ray diagnostic apparatus. The X-ray diagnostic apparatus according to claim 17,
When four or more markers are detected in the image data of one X-ray image before the selection process, the identification processing unit identifies the stent to which each marker belongs, An X-ray diagnostic apparatus characterized in that a relative positional relationship between a plurality of stents in a line image is obtained, and the tracking marker group is identified based on the relative positional relationship after the selection process.

Images