Method and apparatus for calibrating blood vessel image

Abstract

The electronic device according to an embodiment may comprise: a C-arm having an open arc shape; a radiation source connected to the C-arm so as to irradiate a target blood vessel located on a table; and a processor for acquiring a blood vessel image including the target blood vessel, calculating the target distance from a blood vessel point included in the target blood vessel to the radiation source, calculating a correction coefficient corresponding to the blood vessel point on the basis of the calculated target distance, and calculating the physical distance at the blood vessel point by using the calculated correction coefficient.

Description

Method and device for calibrating vascular images

[0001] The disclosure below relates to a calibration method for vascular images.

[0002] Angiography is a diagnostic procedure that uses X-rays to visualize blood vessels and their conditions, making it a useful tool for examining vascular diseases. Accurately measuring blood vessel size during angiography, which is useful for diagnosing vascular diseases, is crucial for assessing the severity of the disease and selecting appropriate treatment methods. For this purpose, quantitative coronary analysis (QCA), which accurately measures blood vessel size, can be used. QCA is crucial for the diagnosis and treatment of coronary artery disease. When using QCA, discrepancies between the size of blood vessels depicted in the image and their actual size, as well as inaccurate assessments of vessel size, can lead to errors in the diagnosis and treatment of vascular diseases. To address these issues, various calibration methods, including catheter calibration and automatic calibration, have been proposed. However, in the case of catheter calibration, using an angiographic catheter as a scaling device for the QCA system may cause problems that may affect the accuracy of vessel diameter measurements, and changes in catheter configuration may cause differences in contour detection due to different levels of X-ray attenuation, which may lead to inaccurate measurement results. In the case of automatic calibration, there is a problem that it can be performed only when the object is positioned exactly at the isocenter.

[0003] A method for processing a blood vessel image performed by a processor according to one embodiment may include the steps of acquiring a blood vessel image including a target blood vessel located on a table, calculating a target distance from a blood vessel point included in the target blood vessel to a radiation source, calculating a calibration factor corresponding to the blood vessel point based on the calculated target distance, and calculating a physical distance from the blood vessel point using the calculated calibration factor.

[0004] The step of calculating the target distance may include the step of calculating a preliminary distance from a pixel corresponding to the blood vessel point in the acquired blood vessel image to the radiation source, and the step of calculating the target distance based on the calculated preliminary distance.

[0005] The step of calculating the preliminary distance may include the step of calculating a first distance from a pixel corresponding to the blood vessel point in the acquired blood vessel image to a center point in the blood vessel image, and the step of calculating the preliminary distance based on the first distance and a second distance which is a distance from the radiation source to the radiation detection unit.

[0006] The distance from the radiation source to the radiation detection unit may represent the distance from the radiation source to the center point within the blood vessel image.

[0007] The step of calculating the target distance based on the preliminary distance may include the step of calculating an average distance from the radiation source to the target blood vessel, and the step of calculating the target distance by dividing the distance from the radiation source to the radiation detection unit by the value calculated by multiplying the calculated preliminary distance by the distance from the radiation source to the target blood vessel.

[0008] The step of calculating the first distance may include the step of calculating a first coordinate of a pixel corresponding to the blood vessel point in the acquired blood vessel image, the step of calculating a second coordinate of a center point in the acquired blood vessel image, and the step of calculating the first distance using the calculated first coordinate, the calculated second coordinate, and an imager pixel spacing.

[0009] The step of calculating an average distance from the radiation source to the relative blood vessel may include calculating an average distance from the radiation source to the target blood vessel based on a first vertical distance from the isodose center point of the C-arm connected to the radiation source to the table and a second vertical distance from the target blood vessel to the table.

[0010] The above isodose center point may be the center of the rotational orbit of the radiation source generated according to the rotation of the C-arm.

[0011] The above-mentioned acquired blood vessel image may be acquired in a state where the radiation source, the target blood vessel, and the isodose center point are arranged in a straight line.

[0012] The step of calculating a correction coefficient corresponding to the blood vessel point may include a step of calculating a correction coefficient corresponding to the blood vessel point by multiplying a value calculated by dividing the calculated target distance by a distance from the radiation source to the radiation detection unit by an imager pixel interval.

[0013] The step of calculating the physical distance at the blood vessel point may include the step of calculating the physical distance corresponding to the blood vessel diameter of the blood vessel point by multiplying a correction coefficient corresponding to the blood vessel point by the number of pixels corresponding to the blood vessel diameter of the blood vessel point appearing in the blood vessel image.

[0014] An electronic device for processing a blood vessel image according to one embodiment may include a C-arm having an open arc shape, a radiation source connected to the C-arm and irradiating radiation to a target blood vessel positioned on a table, and a processor for acquiring a blood vessel image including the target blood vessel, calculating a target distance from a blood vessel point included in the target blood vessel to the radiation source, calculating a correction coefficient corresponding to the blood vessel point based on the calculated object distance, and calculating a physical distance from the blood vessel point using the calculated correction coefficient.

[0015] FIG. 1 is a drawing illustrating the structure of a medical electronic device according to one embodiment.

[0016] FIG. 2 is a drawing illustrating a change in the projection angle of radiation according to the rotation of a C-arm included in an electronic device according to one embodiment.

[0017] FIG. 3 is a diagram illustrating a process by which an electronic device calculates a physical distance to a target blood vessel from a blood vessel image according to one embodiment.

[0018] FIG. 4 is a flowchart schematically illustrating a process by which an electronic device according to one embodiment calculates a physical distance from a blood vessel point included in a target blood vessel.

[0019] FIG. 5 is a diagram illustrating a process in which an electronic device according to one embodiment calculates a correction coefficient for each of a plurality of blood vessel points included in a target blood vessel.

[0020] FIG. 6 is a diagram illustrating a process by which an electronic device according to one embodiment calculates a target distance from a blood vessel point included in a target blood vessel to a radiation source.

[0021] FIG. 7 is a diagram illustrating a process by which an electronic device according to one embodiment calculates a first distance from a pixel corresponding to a blood vessel point in a blood vessel image to a center point in the blood vessel image.

[0022] FIG. 8 is a diagram illustrating a process by which an electronic device according to one embodiment calculates an average distance from a radiation source to a target blood vessel.

[0023] FIG. 9 is a diagram illustrating a process by which an electronic device according to one embodiment calculates a physical distance from a blood vessel point included in a target blood vessel.

[0024] Specific structural or functional descriptions of the embodiments are disclosed for illustrative purposes only and may be modified and implemented in various forms. Therefore, the actual implementation is not limited to the specific embodiments disclosed, and the scope of this specification includes modifications, equivalents, or alternatives within the technical concepts described in the embodiments.

[0025] Although terms such as "first" or "second" may be used to describe various components, these terms should be interpreted solely to distinguish one component from another. For example, a first component may be referred to as a second component, and similarly, a second component may also be referred to as a first component.

[0026] When it is said that a component is "connected" to another component, it should be understood that it may be directly connected or connected to that other component, but there may also be other components in between.

[0027] Singular expressions include plural expressions unless the context clearly dictates otherwise. In this specification, the terms "comprises" or "has" should be understood to indicate the presence of a described feature, number, step, operation, component, part, or combination thereof, but not to exclude the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0028] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by a person of ordinary skill in the art. Terms defined in commonly used dictionaries should be interpreted to have a meaning consistent with their meaning in the context of the relevant technology, and will not be interpreted in an idealized or overly formal sense unless explicitly defined herein.

[0029] Hereinafter, embodiments will be described in detail with reference to the attached drawings. In the description with reference to the attached drawings, identical components are assigned the same reference numerals regardless of the drawing numbers, and redundant descriptions thereof will be omitted.

[0030]

[0031] FIG. 1 is a drawing illustrating the structure of a medical electronic device according to one embodiment.

[0032] A medical electronic device (100) according to one embodiment (hereinafter, “electronic device”) may refer to a device that generates a blood vessel image by irradiating a blood vessel of a subject with radiation. The types of blood vessels may include, for example, a left main coronary artery (LM), a left anterior descending artery (LAD), a left circumflex artery (LCX), a right cornary artery (RCA), etc. The electronic device (100) may generate a blood vessel image using angiography.

[0033] In one embodiment, the electronic device (100) may include a body (11), a C-arm (12), a radiation irradiation unit (13), and a radiation detection unit (14). The electronic device (100) may further include a table (15) for positioning a subject and a processor (101) for processing blood vessel images.

[0034] The C-arm (12) may have a curved C-shaped arc shape with one side open. For example, when the C-arm (12) is vertically erected based on the floor on which the electronic device (100) is placed, the C-arm (12) may have a shape that is symmetrical based on a plane that is parallel to the floor and includes an isocenter (111). The isocenter (111) is a portion or point that serves as the center of a flux of radiation emitted from various positions despite the rotation of the C-arm, and may be defined as a point where the first rotation axis and the second rotation axis of the C-arm intersect. The isocenter (111) may indicate the center of a rotational orbit of a radiation irradiation unit (13) (or a radiation source (not shown)) generated according to the rotation of the C-arm (12). The C-arm (12) may have a shape that is open toward the isocenter (111).

[0035] The body part (11) can be connected to the C-arm (12). The body part (11) can be mechanically coupled to the C-arm (12). The C-arm (12) can rotate with respect to the body part (11). The C-arm (12) can rotate within the xz plane with respect to the body part (11). For example, a protrusion included in the body part (11) and a moving guide included in the C-arm (12) can be coupled to each other, and the C-arm (12) can rotate within the xz plane along the moving guide with respect to a rotation axis that is parallel to the x-axis and passes through the isodose center point (111). In addition, the C-arm (12) can also rotate within the yz plane with respect to the body part (11). For example, in a state where the point where the body part (11) and the C-arm (12) contact each other is fixed, the C-arm (12) can rotate within the yz plane based on a rotation axis that is parallel to the x-axis and passes through the isocenter point (111).

[0036] The electronic device (100) may include a radiation irradiation unit (13) and a radiation detection unit (14) arranged to face each other with an isodose center point (111) interposed on the inner surface of the C-arm (12). Each of the radiation irradiation unit (13) and the radiation detection unit (14) may be connected to the C-arm (12). The radiation irradiation unit (13) may include one or more radiation sources and may emit radiation toward a subject through one or more radiation sources. The radiation detection unit (14) may include a radiation detection sensor and may detect radiation emitted from the radiation irradiation unit (13) and penetrating a blood vessel of a subject through the radiation detection sensor.

[0037] A subject can be laid down on the table (15). More specifically, the table (15) may include a table top (15-1) on which the subject can be laid down, and a table support (15-2) that supports the table top (15-1). The table support (15-2) may be fixed to a floor surface. For example, the table top (15-1) may be movably coupled to the table support (15-2). The electronic device (100) may further include an actuator (not shown) that changes the position of the table top (15-1) relative to the table support (15-2). The electronic device (100) may move the table top (15-1) relative to the table support (15-2) through the actuator (not shown). The actuator (not shown) may include a motor (e.g., an electric motor) and a power transmission structure.

[0038] The table top (15-1) can move left-right and up-down with respect to the table support (15-2). For example, the electronic device (100) can move the table top (15-1) left-right on a plane parallel to the surface of the table (e.g., xy plane). The surface of the table may refer to the upper surface of the table top (15-1). The electronic device (100) can also move the table top (15-1) up-down on an axis perpendicular to the plane parallel to the surface of the table (e.g., xy plane) (e.g., z axis). In the following description, moving the table (15) may refer to moving the table top (15-1) with respect to the table support (15-2). For example, the electronic device (100) can move the table (15) in order to accurately irradiate radiation to a target blood vessel of a subject.

[0039] The electronic device (100) can control the C-arm (12) to rotate around the subject of the procedure positioned on the table (15). After fixing the C-arm (12), the electronic device (100) can irradiate the target blood vessel of the subject of the procedure on the table (15) with radiation through the radiation source of the radiation irradiation unit (13) connected to the C-arm (12). The radiation irradiated to the blood vessel of the subject of the procedure may be X-ray.

[0040]

[0041] FIG. 2 is a drawing illustrating a change in the projection angle of radiation according to the rotation of a C-arm included in an electronic device according to one embodiment.

[0042] In one embodiment, the radiation irradiation unit (13) of the electronic device (100) can irradiate a target blood vessel of a subject positioned on a table (15) using a radiation source (131).

[0043] An electronic device (100) according to one embodiment can rotate a radiation source based on the rotation of a C-arm, based on at least one of a first rotation axis (A-A') that is parallel to a table plane and includes an isodose center point (111) and a second rotation axis (B-B') that is different from the first rotation axis (A-A'). For example, the radiation source can be rotated in one of a plane that is perpendicular to the first rotation axis (A-A') that is parallel to the table plane and includes an isodose center point (111) or a plane that is perpendicular to a second rotation axis (B-B') that is different from the first rotation axis (A-A') and includes an isodose center point (111). The second rotation axis (B-B') can intersect the first rotation axis (A-A'), or, for example, can be orthogonal to each other at the isodose center point (111). For convenience of explanation, an example is described in which the C-arm and the radiation source are rotated in one plane, but this is not limited thereto and they may be rotated about two rotation axes (A-A', B-B') at the same time. For example, the first rotation axis (A-A') may be parallel to the y-axis, in which case the radiation source may be rotated in the xz-plane perpendicular to the y-axis. For example, the second rotation axis (B-B') may be parallel to the x-axis, in which case the radiation source may be rotated in the yz-plane perpendicular to the x-axis.

[0044] For example, the electronic device (100) can rotate the C-arm (12) with respect to the body (11) about a first rotation axis (A-A'). The first rotation axis (A-A') may represent an axis connecting the point where the C-arm (12) and the body (11) are coupled and the isodose center point (111). The position of the radiation source (131) may change according to the rotation of the C-arm (12). For example, according to the rotation of the C-arm (12) about the first rotation axis (A-A'), the radiation source (131) may rotate along a rotational orbit on a plane (190) that is perpendicular to the first rotation axis (A-A') and includes the isodose center point (111). In FIG. 2, the XZ plane is exemplarily illustrated as the plane (190) that is perpendicular to the first rotation axis (A-A').

[0045] The radiation source (131) can rotate in a rotational orbit similar to a circle on a plane (190) according to the rotation of the C-arm (12). The rotational orbit along which the radiation source (131) moves when the C-arm (12) rotates is not geometrically a circle, and may become a circle that is distorted to some extent due to deflection, vibration, etc. of the C-arm (12).

[0046] In addition, the electronic device (100) can also rotate the C-arm (12) with respect to the body (11) about the second rotation axis (B-B'). The second rotation axis (B-B') may be an axis that intersects (e.g., is perpendicular to) the first rotation axis (A-A') while passing through the isodose center point (111). For example, according to the rotation of the C-arm (12) about the second rotation axis (B-B'), the radiation source (131) can rotate in a rotational orbit on a plane that includes the isodose center point (111) and is perpendicular to the second rotation axis (B-B'). For reference, FIG. 2 illustrates an example in which the C-arm rotates about the first rotation axis (A-A') and the second rotation axis (B-B') also rotates. However, when rotation of the C-arm (12) occurs based on the second rotation axis (B-B') while the radiation source (131) and the radiation detector (14) are positioned on the Z-axis, the second rotation axis (B-B') is parallel to the X-axis, and the radiation source (131) can be rotated in a rotational orbit on the YZ plane.

[0047] When the position of the radiation source (131) changes according to the rotation of the C-arm (12), the projection angle (θ) (231) of the radiation emitted from the radiation source (131) may change. In other words, the projection angle (231) of the radiation emitted from the radiation source may change according to the rotation of the C-arm (12).

[0048] The projection angle (231) of the radiation may represent an angle between an axis (e.g., Z-axis) perpendicular to a plane including the surface of the table (15) and an axis (211) corresponding to the irradiation direction of the radiation emitted from the radiation source (131). The irradiation direction of the radiation may represent a direction from the radiation irradiation unit (13) (or the radiation source (131)) toward the radiation detection unit (14) (or the radiation detection sensor). The axis (211) corresponding to the irradiation direction of the radiation may represent an axis connecting the radiation irradiation unit (13) and the radiation detection unit (14). The projection angle (231) of the radiation may be an angle between -180 degrees and 180 degrees.

[0049] The isodose center point (111) can be defined in various ways based on the rotation of the C-arm (12). For example, the isodose center point (111) can represent a point where radiation irradiated from various locations of the radiation source according to the rotation of the C-arm (12) is concentrated. For another example, the isodose center point (111) can represent the geometric center of the rotational orbit of the radiation source (131). For another example, the isodose center point (111) can represent the rotational center of the C-arm (12).

[0050]

[0051] FIG. 3 is a diagram illustrating a process by which an electronic device calculates a physical distance to a target blood vessel from a blood vessel image according to one embodiment.

[0052] In one embodiment, a subject (120) may be positioned on a table top (15-1) of an electronic device (100). The electronic device (100) may generate a blood vessel image (130) including a target blood vessel (320) of the subject (120) using radiation emitted from a radiation source (131).

[0053] The processor (101) of the electronic device (100) can acquire a blood vessel image (130) including a target blood vessel (320), and derive quantitative analysis results, such as the diameter of the target blood vessel (320) and the length of the lesion, from the acquired blood vessel image (130). In order to derive quantitative analysis results related to the target blood vessel (320) from the blood vessel image (130), the processor (101) needs to convert the distance measured within the blood vessel image (130) into a real-world physical distance, such as μm, mm, or cm. Accordingly, the processor (101) can convert the distance measured within the blood vessel image (130) into a physical distance by utilizing a calibration factor.

[0054] Specifically, the physical distance can be calculated by multiplying the number of pixels corresponding to the distance measured within the blood vessel image (130) by the correction factor. For example, the physical distance can be expressed as in Mathematical Expression 1 below.

[0055] [Mathematical Formula 1]

[0056]

[0057] Referring to Mathematical Formula 1, the correction factor may represent a physical distance corresponding to the length (e.g., horizontal or vertical) of a single pixel constituting a blood vessel image (130). To accurately calculate the physical distance, it is necessary to accurately calculate the correction factor. The correction factor may represent the spatial relationship between an object within the blood vessel image and an object in the real world.

[0058] In order to accurately calculate a physical distance to a target blood vessel (320), an electronic device according to one embodiment may individually calculate a correction coefficient for each of a plurality of blood vessel points included in the target blood vessel (320). The correction coefficient for a blood vessel point included in the target blood vessel (320) may be calculated using the distance from the blood vessel point to the radiation source (131). Since the distance to the radiation source (131) is different for each blood vessel point, the correction coefficient calculated by the electronic device for each of the plurality of blood vessel points included in the target blood vessel (320) may be different. In order to calculate a physical distance from a blood vessel point included in the target blood vessel (320), the electronic device may calculate a correction coefficient for the corresponding blood vessel point. For example, the electronic device may calculate a correction coefficient for the corresponding blood vessel point in order to calculate a blood vessel diameter at the blood vessel point included in the target blood vessel (320).

[0059]

[0060] FIG. 4 is a flowchart schematically illustrating a process by which an electronic device according to one embodiment calculates a physical distance from a blood vessel point included in a target blood vessel.

[0061] In operation (410), the processor of the electronic device can obtain a blood vessel image including a target blood vessel located on a table.

[0062] A radiation irradiation unit (e.g., radiation irradiation unit (13) of FIG. 3) of an electronic device can irradiate a target blood vessel located on a table using a radiation source (e.g., radiation source (131) of FIG. 3) connected to a C-arm. The target blood vessel can include a plurality of blood vessel points. For example, each of the plurality of blood vessel points included in the target blood vessel can be a blood vessel point positioned at a centerline of the target blood vessel. A radiation detection unit (e.g., radiation detection unit (14) of FIG. 3) of the electronic device can detect radiation that has passed through the target blood vessel. For example, a processor of the electronic device can generate (or acquire) a blood vessel image including the target blood vessel located on the table using radiation detected from the radiation detection unit.

[0063] An electronic device must calculate a calibration factor to calculate a physical distance (e.g., a diameter of a blood vessel) to a target blood vessel. The calibration factor can represent the spatial relationship between an object within a blood vessel image and an object in the real world. The electronic device can calculate a separate calibration factor for each blood vessel point included in the target blood vessel. This is because the electronic device must use the calibration factor for each blood vessel point to calculate the physical distance from the blood vessel point of the target blood vessel. The operation described below is an operation in which the electronic device calculates a calibration factor for one blood vessel point and calculates the physical distance from one blood vessel point.

[0064] Next, in operation (420), the electronic device can calculate the target distance from a blood vessel point included in the target blood vessel to the radiation source.

[0065] An electronic device may use a blood vessel image including a target blood vessel to calculate a target distance from a blood vessel point included in the target blood vessel to a radiation source. Specifically, the electronic device may calculate a preliminary distance from a pixel corresponding to a blood vessel point in the blood vessel image including the target blood vessel to the radiation source. The electronic device may use the calculated preliminary distance to calculate a target distance from a blood vessel point included in the target blood vessel to the radiation source.

[0066] In operation (430), the electronic device can calculate a correction coefficient corresponding to the blood vessel point based on the calculated target distance.

[0067] The correction factor may represent a physical distance corresponding to the length of one pixel (e.g., the horizontal length of the pixel or the vertical length of the pixel) that constitutes a vascular image including the target blood vessel. The electronic device may calculate the correction factor using the calculated target distance, the distance from the radiation source to the radiation detector, and the imager pixel spacing. Here, the imager pixel spacing may represent the length of one pixel (e.g., the horizontal length of the pixel or the vertical length of the pixel) that constitutes the vascular image.

[0068] In operation (440), the electronic device can calculate the physical distance from the blood vessel point using the calculated correction coefficient.

[0069] An electronic device can derive quantitative analysis results, such as the diameter of a blood vessel or the length of a lesion at a blood vessel point within a target blood vessel. The electronic device can derive these quantitative analysis results using blood vessel images. The electronic device needs to convert the distance measured within the blood vessel image into a real-world physical distance, such as μm, mm, or cm. Therefore, the electronic device can use the calculated correction factor to convert the distance measured within the blood vessel image into a physical distance.

[0070]

[0071] FIG. 5 is a diagram illustrating a process in which an electronic device according to one embodiment calculates a correction coefficient for each of a plurality of blood vessel points included in a target blood vessel.

[0072] In one embodiment, the electronic device can calculate a correction factor for each of a plurality of blood vessel points included in a target blood vessel.

[0073] First, the electronic device can detect radiation that has passed through a target blood vessel (520) through a radiation detector (e.g., radiation detector (14) of FIG. 3), and can process the result of the radiation detector to obtain a blood vessel image (540) including the target blood vessel (520). The target blood vessel (520) may be, for example, a left coronary artery (LCA) or a right coronary artery (RCA). In addition, the target blood vessel (520) may include a left anterior descending artery (LAD) and a left circumflex artery (LCX) connected to the left coronary artery (LCA). However, the examples of the target blood vessel (520) are not limited to the above.

[0074] The electronic device may use the acquired blood vessel image (540) to calculate a correction coefficient for each of a plurality of blood vessel points included in the target blood vessel (520). At this time, in order to calculate the correction coefficient for each of a plurality of blood vessel points included in the target blood vessel (520), it may be considered that the blood vessel image (540) is positioned at the same location as the location where the radiation detector is positioned. The electronic device may calculate a first correction coefficient corresponding to a first blood vessel point included in the target blood vessel (520) in order to calculate a physical distance from the first blood vessel point included in the target blood vessel (520). For example, when the target blood vessel (520) is the right coronary artery, the first blood vessel point may be a proximal point of the right coronary artery. Similarly, the electronic device may calculate a second correction coefficient corresponding to a second blood vessel point in order to calculate a physical distance from the second blood vessel point included in the target blood vessel (520). For example, when the target blood vessel (520) is the right coronary artery, the second blood vessel point may be a distal point of the right coronary artery. The first correction factor and the second correction factor may be the same or different. For reference, the first blood vessel point and the second blood vessel point may have different heights in the direction of gravity. For example, a subject (e.g., the subject (120) of FIG. 3) may be positioned with his / her back against a tabletop (e.g., the tabletop (15-1) of FIG. 3) of an electronic device (e.g., the electronic device (100) of FIG. 3). When the subject is positioned with his / her back against the tabletop, the electronic device may acquire a blood vessel image (540) captured in a direction perpendicular to the sagittal plane of the subject. Each point of the target blood vessel (520) in the blood vessel image (540) captured in a direction perpendicular to the sagittal plane of the subject may have different heights in the direction of gravity. For example, if the target blood vessels (520) included in the blood vessel image (540) are the left anterior descending artery and the left circumflex artery, the first blood vessel point may be the proximal point of the left anterior descending artery.At this time, the proximal point of the left anterior descending artery may be located at a height of 170 mm from the table top. In addition, the second blood vessel point may be the distal point of the left circumflex artery. At this time, the distal point of the left circumflex artery may be located at a height of 136 mm from the table top. In other words, different blood vessel points within the target blood vessel (520) may each have different heights in the direction of gravity. Accordingly, the electronic device may calculate the first correction coefficient and the second correction coefficient by considering the different heights of the first blood vessel point and the second blood vessel point.

[0075] The electronic device can calculate a distance from the first blood vessel point to the radiation source (510) to calculate a first correction coefficient corresponding to the first blood vessel point. The electronic device can calculate a distance from a pixel (531) corresponding to the first blood vessel point in the blood vessel image (540) to the radiation source (510) to calculate a distance from the first blood vessel point to the radiation source (510).

[0076] Similarly, the electronic device can calculate a distance from the second blood vessel point to the radiation source (510) to calculate a second correction factor corresponding to the second blood vessel point. The electronic device can calculate a distance from a pixel (532) corresponding to the second blood vessel point in the blood vessel image (540) to the radiation source (510) to calculate a distance from the second blood vessel point to the radiation source (510).

[0077]

[0078] FIG. 6 is a diagram illustrating a process by which an electronic device according to one embodiment calculates a target distance from a blood vessel point included in a target blood vessel to a radiation source.

[0079] In one embodiment, the electronic device can calculate a target distance from a blood vessel point (631) included in a target blood vessel (620) to a radiation source (610). The electronic device can use a blood vessel image (640) including the target blood vessel (620) to calculate the target distance from the blood vessel point (631) to the radiation source (610). In order to calculate the target distance from the blood vessel point included in the target blood vessel (620) to the radiation source, it may be considered that the blood vessel image (640) is positioned at the same location as the location where the radiation detection unit is positioned.

[0080] In one embodiment, the electronic device may first calculate a preliminary distance (Y) from a pixel (641) corresponding to a blood vessel point (631) in a blood vessel image (640) including the target blood vessel (620) to the radiation source (620) in order to calculate a target distance (X) from a blood vessel point (631) included in a target blood vessel (620) to the radiation source (620). In other words, the electronic device may calculate the target distance (X) based on the calculated preliminary distance (Y). Hereinafter, a process of calculating the preliminary distance (Y) from a pixel (641) corresponding to a blood vessel point (631) in a blood vessel image (640) to the radiation source (610) will be described.

[0081] In one embodiment, the electronic device can calculate a first distance (d1) from a pixel (641) corresponding to a blood vessel point (631) in the blood vessel image (640) to a center point (650) in the blood vessel image (640). The electronic device can obtain a second distance (SID) from the radiation source (610) to the radiation detector. The electronic device can obtain the second distance (SID) from the radiation source (610) to the radiation detector from metadata of Digital Imaging and Communications in Medicine (DICOM). DICOM can represent a standard specification for storing and transmitting data related to images generated by electronic devices. The second distance (SID) from the radiation source (610) to the radiation detector can represent a distance from the radiation source (610) to the center point (650) in the blood vessel image (640).

[0082] In one embodiment, the electronic device can calculate the preliminary distance (Y) based on the first distance (d1) and the second distance (SID). The first straight line connecting the radiation source (610) and the center point (650) in the blood vessel image (640) and the second straight line connecting the center point (650) in the blood vessel image (640) and the pixel (641) corresponding to the blood vessel point (631) in the blood vessel image (640) can be orthogonal to each other. Accordingly, the electronic device can calculate the preliminary distance (Y) according to the following mathematical expression 2.

[0083] [Equation 2]

[0084]

[0085] In mathematical expression 2, Y may represent a preliminary distance from a pixel (641) corresponding to a blood vessel point (631) in a blood vessel image (640) to a radiation source (610), d1 may represent a first distance from a pixel (641) corresponding to a blood vessel point (631) in a blood vessel image (640) to a central point (650) in a blood vessel image (640), and SID may represent a second distance from a radiation source (610) to a radiation detection unit.

[0086] In one embodiment, the electronic device can calculate the target distance (X) based on the calculated preliminary distance (Y). The electronic device can calculate the average distance (SOD) from the radiation source (610) to the target blood vessel (620). The average distance (SOD) from the radiation source (610) to the target blood vessel (620) can represent the distance from the radiation source (610) to the center point (660) of the target blood vessel (620). The center point (660) of the target blood vessel (620) can be positioned on a straight line connecting the radiation source (610) and the center point (650) in the blood vessel image (640).

[0087] In one embodiment, the electronic device can calculate the target distance (X) by dividing the calculated value by multiplying the calculated reserve distance (Y) by the average distance from the radiation source (610) to the target blood vessel (620) and the distance (SID) from the radiation source (610) to the radiation detector. In other words, the electronic device can calculate the target distance (X) according to the following mathematical expression 3.

[0088] [Equation 3]

[0089]

[0090] In mathematical expression 3, X may represent a target distance from a blood vessel point (631) included in a target blood vessel (620) to a radiation source (610), Y may represent a preliminary distance from a pixel (641) corresponding to a blood vessel point (631) in a blood vessel image (640) to a radiation source (610), SOD may represent an average distance from a radiation source (610) to a target blood vessel (620), and SID may represent a second distance from a radiation source (610) to a radiation detection unit.

[0091]

[0092] FIG. 7 is a diagram illustrating a process by which an electronic device according to one embodiment calculates a first distance from a pixel corresponding to a blood vessel point in a blood vessel image to a center point in the blood vessel image.

[0093] In one embodiment, the electronic device can calculate a first distance (d1) from a pixel (741) corresponding to a blood vessel point within the blood vessel image (740) to a center point (750) within the blood vessel image (740).

[0094] In one embodiment, the electronic device can calculate a first coordinate of a pixel (741) corresponding to a blood vessel point within a blood vessel image (740). The electronic device can calculate a second coordinate of a center point (750) within the blood vessel image (740). The electronic device can calculate a first distance (d1) using the calculated first coordinate, the calculated second coordinate, and an imager pixel spacing. Here, the imager pixel spacing can represent a length (e.g., horizontal length or vertical length) of one pixel constituting the blood vessel image.

[0095] In one embodiment, the electronic device can obtain size information of a pixel array constituting a blood vessel image (740) from metadata of DICOM. The size information of the pixel array can include the number of rows and the number of columns constituting the pixel array. The electronic device can set the coordinates of a reference point (711) located at the upper left in the blood vessel image (740) to (0,0). The electronic device can increase the x-coordinate by a value obtained by dividing the distance moved in the first axis (721) based on the reference point (711) by the horizontal length of the pixel. The electronic device can increase the y-coordinate by a value obtained by dividing the distance moved in the second axis (722) based on the reference point (711) by the vertical length of the pixel.

[0096] Hereinafter, a process for calculating the first coordinates of a pixel (741) corresponding to a blood vessel point in a blood vessel image (740) will be described. First, the electronic device can calculate the center point of the pixel as the coordinates of the pixel. The electronic device can calculate the position of the pixel (741) corresponding to the blood vessel point. The pixel (741) corresponding to the blood vessel point may be located at the a-th row from the top and the b-th column from the left. In this case, the electronic device can calculate the coordinates of the pixel (741) corresponding to the blood vessel point as (a-0.5, b-0.5).

[0097] The electronic device can calculate the x-coordinate of the center point (750) within the blood vessel image (740) as a value obtained by dividing the number of columns constituting the pixel array by 2, and can calculate the y-coordinate as a value obtained by dividing the number of rows constituting the pixel array by 2. For example, when the number of columns and rows constituting the pixel array is 8, the coordinate of the center point (750) within the blood vessel image (740) can be calculated as (4, 4).

[0098] In one embodiment, the electronic device can calculate the first distance (d1) using the calculated first coordinate, the calculated second coordinate, and the imager pixel spacing. The electronic device can calculate the first distance (d1) according to the following mathematical expression 4.

[0099] [Equation 4]

[0100]

[0101] In mathematical expression 4, d1 is the first distance from the pixel (741) corresponding to the blood vessel point in the blood vessel image (740) to the center point (750) in the blood vessel image (740), (P x , P y ) is the first coordinate of the pixel (741) corresponding to the blood vessel point in the blood vessel image (740), (C x , C y ) may represent the second coordinate of the center point (750) within the blood vessel image (740), and IP may represent the imager pixel spacing.

[0102]

[0103] FIG. 8 is a diagram illustrating a process by which an electronic device according to one embodiment calculates an average distance from a radiation source to a target blood vessel.

[0104] Hereinafter, a process for calculating the average distance (SOD) from a radiation source (13) to a target blood vessel (320) by an electronic device is described. FIG. 8 is a side view of an electronic device (e.g., an electronic device (100) of FIG. 1) viewed in the XZ plane. Before irradiating a target blood vessel (320) with radiation using a radiation source (131), the electronic device can move the table top (15-1) to align the radiation source (131), the target blood vessel (320), and the isodose center point (111) in a straight line. In other words, a blood vessel image including a target blood vessel (320) (e.g., a blood vessel image (540) of FIG. 5, a blood vessel image (640) of FIG. 6, a blood vessel image (740) of FIG. 7) may be an image acquired in a state where the radiation source (131), the target blood vessel (320), and the isodose center point (111) are arranged in a straight line.

[0105] In one embodiment, the electronic device may calculate a first value (d1-d2) by subtracting a second vertical distance (d2) from the target blood vessel (120) to the table (15) from a first vertical distance (d1) from the isodose center point (111) of the C-arm to the table (15). The first value (d1-d2) may represent a vertical distance from the isodose center point (111) to the target blood vessel (320). In addition, the electronic device may calculate a second value by dividing the calculated first value (d1-d2) by a cosine value (cos(θ)) of the radiation irradiation angle (e.g., the radiation irradiation angle (231) of FIG. 2). The second value ( ) may represent a straight-line distance from the isodose center point (111) to the target blood vessel (320). The electronic device may calculate an average distance (z) from the radiation source (131) to the target blood vessel (320) by subtracting the second value (i.e., the straight-line distance from the isodose center point (111) to the target blood vessel (320)) calculated from the straight-line distance (d3) from the radiation source (131) to the isodose center point (111).

[0106] In summary, the average distance from the radiation source (131) to the target blood vessel (320) can be calculated as in mathematical equation 5 below.

[0107] [Equation 5]

[0108]

[0109] In the above mathematical expression 5, SOD is the average distance from the radiation source (131) to the target blood vessel (320), Source to Isocenter is the straight-line distance (d3) from the radiation source (131) to the isodose center point (111), Isocenter to table is the vertical distance (d1) from the isodose center point (111) to the table (15), Object height is the vertical distance (d2) from the target blood vessel (320) to the table (15), can represent the angle of irradiation of radiation.

[0110]

[0111] FIG. 9 is a diagram illustrating a process by which an electronic device according to one embodiment calculates a physical distance from a blood vessel point (930) included in a target blood vessel.

[0112] In one embodiment, the electronic device can calculate a correction coefficient corresponding to a blood vessel point (930) included in a target blood vessel (920). The electronic device can calculate the correction coefficient corresponding to the blood vessel point (930) by multiplying the value calculated by dividing the target distance from the blood vessel point (930) included in the target blood vessel (920) to the radiation source by the second distance (SID) from the radiation source to the radiation detector by the imager pixel spacing (IP). That is, the correction coefficient corresponding to the blood vessel point (930) included in the target blood vessel (920) can be expressed as in the following mathematical expression 6.

[0113] [Equation 6]

[0114]

[0115] In mathematical expression 6, SID may represent a second distance from a radiation source to a radiation detector, and IP may represent an imager pixel spacing. The distance from a radiation source to a radiation detector (SID) and the imager pixel spacing (IP) may be extracted from metadata of Digital Imaging and Communications in Medicine (DICOM).

[0116] In one embodiment, the electronic device can calculate a correction factor corresponding to a blood vessel point (930) included in a target blood vessel (920) and convert a distance measured in a blood vessel image (940) into a physical distance in real space by using the calculated correction factor. The electronic device can calculate a physical distance at a blood vessel point (930) by using the correction factor corresponding to the blood vessel point (930). Here, the physical distance at the blood vessel point (930) can represent a physical distance related to a blood vessel near the blood vessel point (930).

[0117] For example, the electronic device can calculate a physical distance corresponding to the diameter of the blood vessel of the blood vessel point (930) by multiplying a correction factor corresponding to the blood vessel point (930) by the number of pixels corresponding to the blood vessel diameter of the blood vessel point (930) appearing in the blood vessel image (940). As another example, the electronic device can detect a lesion at the blood vessel point (930). In this case, the electronic device can also calculate a physical distance corresponding to the length of the lesion appearing at the blood vessel point (930) by multiplying a correction factor corresponding to the blood vessel point (930) by the number of pixels corresponding to the length of the lesion of the blood vessel point (930) appearing in the blood vessel image (940). In addition, the electronic device can derive various quantitative analysis results related to the blood vessel point (930) within the blood vessel image (940) by using the correction factor corresponding to the blood vessel point (930).

[0118] Referring to FIG. 9, the electronic device can label the boundary of the target blood vessel (920) in the blood vessel image (940) including the target blood vessel (920), and after performing the labeling, can estimate the blood vessel diameter at one blood vessel point (930) included in the centerline (921) of the target blood vessel (920). For example, the electronic device can generate a line segment (950) that is perpendicular to the centerline (921) of the target blood vessel at the blood vessel point (930) and does not go beyond the boundary of the target blood vessel (920). The electronic device can measure the number of pixels (e.g., 20.9) appearing in the generated line segment (950). The electronic device can estimate the blood vessel diameter (e.g., 1.9 mm) at the blood vessel point (930) by multiplying the measured number of pixels (e.g., 20.9) by a correction factor corresponding to the blood vessel point (930).

[0119]

[0120] The embodiments described above may be implemented using hardware components, software components, and / or a combination of hardware components and software components. For example, the devices, methods, and components described in the embodiments may be implemented using a general-purpose computer or a special-purpose computer, such as, for example, a processor, a controller, an arithmetic logic unit (ALU), a digital signal processor, a microcomputer, a field programmable gate array (FPGA), a programmable logic unit (PLU), a microprocessor, or any other device capable of executing instructions and responding to them. The processing device may execute an operating system (OS) and software applications running on the operating system. Furthermore, the processing device may access, store, manipulate, process, and generate data in response to the execution of the software. For ease of understanding, the processing device is sometimes described as being used alone; however, one of ordinary skill in the art will recognize that the processing device may include multiple processing elements and / or multiple types of processing elements. For example, a processing unit may include multiple processors, or a processor and a controller. Other processing configurations, such as parallel processors, are also possible.

[0121] Software may include a computer program, code, instructions, or a combination of one or more of these, which may configure a processing device to perform a desired operation or may, independently or collectively, command the processing device. The software and / or data may be permanently or temporarily embodied in any type of machine, component, physical device, virtual equipment, computer storage medium or device, or transmitted signal wave, for interpretation by the processing device or for providing instructions or data to the processing device. The software may also be distributed over networked computer systems and stored or executed in a distributed manner. The software and data may be stored on a computer-readable recording medium.

[0122] The method according to the embodiment may be implemented in the form of program commands that can be executed through various computer means and recorded on a computer-readable medium. The computer-readable medium may include program commands, data files, data structures, etc., alone or in combination, and the program commands recorded on the medium may be those specially designed and configured for the embodiment or may be known and available to those skilled in the art of computer software. Examples of the computer-readable recording medium include magnetic media such as hard disks, floppy disks, and magnetic tapes, optical media such as CD-ROMs and DVDs, magneto-optical media such as floptical disks, and hardware devices specially configured to store and execute program commands such as ROMs, RAMs, and flash memories. Examples of program commands include not only machine language codes such as those generated by a compiler, but also high-level language codes that can be executed by a computer using an interpreter, etc.

[0123] The hardware devices described above may be configured to operate as one or more software modules to perform the operations of the embodiments, and vice versa.

[0124] Although the embodiments described above have been described with limited drawings, those skilled in the art will appreciate that various technical modifications and variations can be applied based on the described embodiments. For example, appropriate results can still be achieved even if the described techniques are performed in a different order than described, and / or components of the described systems, structures, devices, circuits, etc. are combined or combined in a different manner than described, or are replaced or substituted with other components or equivalents.

[0125] Therefore, other implementations, other embodiments, and equivalents to the claims also fall within the scope of the claims described below.

Claims

1. In a method for processing blood vessel images performed by a processor, A step of acquiring a blood vessel image including a target blood vessel located on a table; A step of calculating a first target distance from a first blood vessel point included in the target blood vessel to a radiation source; A step of calculating a first calibration factor corresponding to the first blood vessel point based on the calculated first target distance; and A step of calculating a first physical distance from the first blood vessel point using the first correction coefficient calculated above. A method for processing a vascular image including:

2. In paragraph 1, The step of calculating the first target distance is: A step of calculating a preliminary distance from a pixel corresponding to the first blood vessel point in the acquired blood vessel image to the radiation source; and A step of calculating the first target distance based on the calculated preliminary distance. A method for processing a vascular image including:

3. In paragraph 2, The step of calculating the above reserve distance is: A step of calculating a first distance from a pixel corresponding to the first blood vessel point in the acquired blood vessel image to a center point in the blood vessel image; and A step of calculating the preliminary distance based on the first distance and the second distance from the radiation source to the radiation detection unit. A method for processing a vascular image including:

4. In paragraph 3, The distance from the radiation source to the radiation detector is, Indicates the distance from the radiation source to the center point within the blood vessel image, Method for processing vascular images.

5. In paragraph 2, The step of calculating the first target distance based on the above preliminary distance is: A step of calculating an average distance from the radiation source to the target blood vessel; and A step of calculating the first target distance by dividing the distance from the radiation source to the radiation detection unit by the value calculated by multiplying the average distance from the radiation source to the target blood vessel by the calculated reserve distance. A method for processing a vascular image including:

6. In paragraph 3, The step of calculating the first distance is: A step of calculating a first coordinate of a pixel corresponding to the first blood vessel point in the acquired blood vessel image; A step of calculating the second coordinates of the center point within the acquired blood vessel image; and A step of calculating the first distance using the calculated first coordinate, the calculated second coordinate, and the imager pixel spacing. A method for processing a vascular image including:

7. In paragraph 5, The step of calculating the average distance from the radiation source to the target blood vessel is as follows: A step of calculating an average distance from the radiation source to the target blood vessel based on a first vertical distance from the isodose center point of the C-arm connected to the radiation source to the table and a second vertical distance from the target blood vessel to the table. A method for processing a vascular image including:

8. In paragraph 7, The above isodose center point is, The center of the rotational orbit of the radiation source generated by the rotation of the C-arm, Method for processing vascular images.

9. In paragraph 7, The above acquired blood vessel image is, A blood vessel image obtained in a state where the radiation source, the target blood vessel, and the isodose center point are arranged in a straight line. A method for processing a vascular image including:

10. In paragraph 1, The step of calculating the first correction coefficient corresponding to the first blood vessel point is: A step of calculating a first correction coefficient corresponding to the first blood vessel point by multiplying the value calculated by dividing the calculated first target distance by the distance from the radiation source to the radiation detection unit by the imager pixel interval. A method for processing a vascular image including:

11. In paragraph 1, The step of calculating the first physical distance from the first blood vessel point is: A step of calculating a first physical distance corresponding to the blood vessel diameter of the first blood vessel point by multiplying a first correction coefficient corresponding to the first blood vessel point by the number of pixels corresponding to the blood vessel diameter of the first blood vessel point appearing in the blood vessel image. A method for processing a vascular image including:

12. In paragraph 1, A step of calculating a second target distance from a second blood vessel point included in the target blood vessel to the radiation source; A step of calculating a second correction coefficient corresponding to the second blood vessel point based on the calculated second target distance; and A step of calculating a second physical distance from the second blood vessel point using the second correction coefficient. A method for processing a vascular image further comprising:

13. In an electronic device for processing blood vessel images, C-arm with open arc shape; A radiation source that is connected to the C-arm and irradiates a target blood vessel positioned on the table; and A processor that acquires a blood vessel image including the target blood vessel, calculates a first target distance from a first blood vessel point included in the target blood vessel to the radiation source, calculates a first correction coefficient corresponding to the first blood vessel point based on the calculated first target distance, and calculates a first physical distance from the first blood vessel point using the calculated first correction coefficient. Electronic devices containing.

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