Calibration method and apparatus for vascular images

Abstract

An electronic device according to one embodiment includes a C-arm having an open arc shape, a radiation source connected to the C-arm for irradiating a target blood vessel located on a table with radiation, and a processor that acquires a blood vessel image including the target blood vessel, calculates the target distance from the blood vessel point included in the target blood vessel to the radiation source, calculates a calibration coefficient corresponding to the blood vessel point based on the calculated target distance, and calculates the physical distance at the blood vessel point using the calculated calibration coefficient.

Description

[Technical Field]

[0001] The following disclosure relates to a method for calibrating vascular images. [Background Art]

[0002] Angiography is a diagnostic procedure that visualizes blood vessels and their conditions using X-rays, and is a useful tool for examining vascular diseases. In angiography which is useful for the diagnosis of vascular diseases, accurate measurement of vessel size is important for determining the severity of a disease and selecting an appropriate treatment method. For this purpose, quantitative coronary analysis (hereinafter referred to as "QCA") method, which accurately measures vessel size, is used. QCA methods are important for the diagnosis and treatment of coronary artery disease. When using the QCA method, inconsistencies between the size of a vessel depicted in an image and the actual size of the vessel, as well as inaccurate evaluation of vessel size, induce errors in the diagnosis and treatment of vascular diseases. To solve such problems, various correction methods including catheter calibration and automatic correction have been proposed. However, in the case of catheter correction, if an angiographic catheter is used as a scaling device for a QCA system, there may occur problems that affect the accuracy of vessel diameter measurement. Differences in contour detection caused by different levels of X-ray attenuation resulting from changes in catheter configuration lead to the problem of inaccurate measurement results. In the case of automatic correction, there is a problem that it can only be performed when an object is accurately positioned at the isocenter. [Summary of the Invention] [Means for Solving the Problems]

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

[0004] The step of calculating the target distance may include the step of calculating a preliminary distance from the pixel corresponding to the blood vessel location 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 a step of calculating a first distance from a pixel corresponding to the blood vessel location in the acquired blood vessel image to the center point in the blood vessel image, and a step of calculating the preliminary distance based on the first distance and a second distance which is the distance from the radiation source to the radiation detection unit.

[0006] The distance from the radiation source to the radiation detection unit indicates 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 aforementioned preliminary distance may include the step of calculating the average distance from the radiation source to the target blood vessel, and the step of calculating the target distance using a value obtained by multiplying the calculated preliminary distance by the distance from the radiation source to the target blood vessel, and then dividing the result by the distance from the radiation source to the radiation detection unit.

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

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

[0010] The isocenter point may also be the center of the rotational trajectory of the radiation source generated by the rotation of the C-arm.

[0011] The acquired vascular image was obtained with the radiation source, the target blood vessel, and the isocenter point aligned in a straight line.

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

[0013] The step of calculating the physical distance at the blood vessel location may include the step of calculating the physical distance corresponding to the blood vessel diameter at the blood vessel location by multiplying the calibration coefficient corresponding to the blood vessel location by the number of pixels corresponding to the blood vessel diameter at the blood vessel location shown in the blood vessel image.

[0014] An electronic device for processing vascular images according to one embodiment may include a C-arm having an open arc shape, a radiation source connected to the C-arm for irradiating a target vascular object located on a table, and a processor that acquires a vascular image including the target vascular object, calculates a target distance from a vascular point included in the target vascular object to the radiation source, calculates a calibration coefficient corresponding to the vascular point based on the calculated target distance, and calculates the physical distance at the vascular point using the calculated calibration coefficient. [Brief explanation of the drawing]

[0015] [Figure 1] This is a diagram illustrating the structure of a medical electronic device according to one embodiment. [Figure 2] This figure illustrates the change in the projection angle of radiation due to the rotation of a C-arm included in an electronic device according to one embodiment. [Figure 3] This figure illustrates the process by which an electronic device according to one embodiment calculates the physical distance to a target blood vessel from a blood vessel image. [Figure 4] This flowchart schematically illustrates the process by which an electronic device according to one embodiment calculates the physical distance at a point in a blood vessel included in the target blood vessel. [Figure 5] This figure illustrates the process by which an electronic device according to one embodiment calculates calibration coefficients for each of several vascular locations included in the target blood vessel. [Figure 6] This figure illustrates the process by which an electronic device according to one embodiment calculates the target distance from a point in the blood vessel included in the target blood vessel to a radiation source. [Figure 7] This figure illustrates the process by which an electronic device according to one embodiment calculates a first distance from a pixel corresponding to a blood vessel location in a blood vessel image to the center point in the blood vessel image. [Figure 8] This diagram illustrates the process by which an electronic device according to one embodiment calculates the average distance from a radiation source to a target blood vessel. [Figure 9]It is a diagram illustrating a process in which an electronic device according to an embodiment calculates a physical distance at a vascular site included in a target blood vessel. DETAILED DESCRIPTION OF THE INVENTION

[0016] Specific structural or functional descriptions for the embodiments are disclosed for illustrative purposes only and may be modified in various forms. Therefore, the embodiments are not limited to the specifically disclosed forms, and the scope of the present specification includes changes, equivalents, or alternatives falling within the technical concept.

[0017] Terms such as first or second may be used to describe a plurality of components, but such terms should be construed only for the purpose of distinguishing one component from another. For example, a first component may be named as a second component, and similarly, a second component may also be named as a first component.

[0018] When any component is referred to as being "coupled" or "connected" to another component, it should be understood that the component is directly coupled or connected to the other component, but other components may exist therebetween.

[0019] Singular expressions include plural expressions unless the context clearly indicates otherwise. In this specification, terms such as "comprising" or "having" are intended to indicate that the features, numbers, steps, operations, components, parts, or combinations thereof described in the specification are present, and are not to be construed as precluding the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0020] Unless otherwise defined differently, all terms used herein, including technical or scientific terms, have the same meaning as generally understood by a person having ordinary skill in the art to which the present embodiment pertains. Commonly used predefined terms shall be construed as having meanings consistent with the meanings they have in the context of the relevant art, and shall not be construed as having idealized or overly formal meanings unless explicitly defined herein.

[0021] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. In the description with reference to the drawings, the same constituent elements are assigned the same reference numerals regardless of the drawing symbols, and duplicate descriptions thereof will be omitted.

[0022] FIG. 1 is a diagram illustrating the structure of a medical electronic device according to an embodiment.

[0023] A medical electronic device 100 (hereinafter referred to as "electronic device") according to an embodiment refers to a device that irradiates radiation to the blood vessels of a subject to generate a blood vessel image. Types of blood vessels include, for example, left main coronary artery (LM), left anterior descending artery (LAD), left circumflex artery (LCX), right coronary artery (RCA), and the like. The electronic device 100 can generate a blood vessel image using coronary angiography.

[0024] In one embodiment, the electronic device 100 includes a body portion 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 the subject and a processor 101 for processing blood vessel images.

[0025] The C-arm 12 has a curved C-shaped arc with one side open. For example, if the C-arm 12 is erected vertically with respect to the floor on which the electronic device 100 is placed, the C-arm 12 is parallel to the floor but has a symmetrical shape with respect to a plane containing the isocenter 111. The isocenter 111 can be defined as the point where the first and second rotation axes of the C-arm intersect, as the central part or point of the beam of radiation emitted from various positions, regardless of the rotation of the C-arm. The isocenter 111 indicates the center of the rotational trajectory of the radiation irradiation section 13 (or radiation source (not shown)) generated by the rotation of the C-arm 12. The C-arm 12 may also have a shape that opens toward the isocenter 111.

[0026] The torso 11 can be connected to the C-arm 12. The torso 11 can be mechanically coupled to the C-arm 12. The C-arm 12 rotates with respect to the torso 11. The C-arm 12 rotates in the xz plane with respect to the torso 11. For example, a protrusion included in the torso 11 and a moving guide included in the C-arm 12 may be coupled to each other, and the C-arm 12 can rotate in the xz plane parallel to the x-axis and along the moving guide with respect to a rotation axis passing through the isocenter 111. The C-arm 12 can also rotate in the yz plane with respect to the torso 11. For example, with the contact point between the torso 11 and the C-arm 12 fixed, the C-arm 12 can rotate in the yz plane parallel to the Y-axis and with respect to a rotation axis passing through the isocenter 111.

[0027] The electronic device 100 may include a radiation irradiation unit 13 and a radiation detection unit 14 arranged on the inner surface of the C-arm 12, facing each other with the isocenter 111 in between. 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 includes one or more radiation sources and emits radiation toward the patient through one or more radiation sources. The radiation detection unit 14 includes a radiation detection sensor that can detect radiation emitted from the radiation irradiation unit 13 and transmitted through the patient's blood vessels via the radiation detection sensor.

[0028] Table 15 allows a patient to lie on its side. More specifically, table 15 includes a table top plate 15-1 for the patient to lie on and a table support 15-2 that supports the table top plate 15-1. The table support 15-2 is fixed to the bottom surface. For example, the table top plate 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 plate 15-1 with respect to the table support 15-2. The electronic device 100 can move the table top plate 15-1 with respect to the table support 15-2 via the actuator (not shown). The actuator (not shown) includes a motor (e.g., an electric motor) and a power transmission structure.

[0029] The table top plate 15-1 can be moved horizontally and vertically with respect to the table support 15-2. For example, the electronic device 100 may move the table top plate 15-1 horizontally on a plane parallel to the surface of the table (e.g., the xy plane). The surface of the table refers to the upper surface of the table top plate 15-1. The electronic device 100 may also move the table top plate 15-1 vertically on an axis perpendicular to the plane parallel to the surface of the table (e.g., the xy plane) (e.g., the z axis). In the following description, moving the table 15 refers to moving the table top plate 15-1 with respect to the table support 15-2. For example, the electronic device 100 may move the table 15 in order to accurately irradiate the target blood vessel of the patient with radiation.

[0030] The electronic device 100 can control the C-arm 12 so that it rotates around the patient positioned on the table 15. After fixing the C-arm 12, the electronic device 100 irradiates the target blood vessel of the patient 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 onto the patient's blood vessel may be X-rays.

[0031] Figure 2 illustrates the change in the radiation projection angle due to the rotation of a C-arm included in an electronic device according to one embodiment.

[0032] In one embodiment, the radiation irradiation unit 13 of the electronic device 100 can irradiate a target blood vessel of the patient located on the table 15 with radiation using a radiation source 131.

[0033] In one embodiment, the electronic device 100, while including an isocenter 111 based on the rotation of the C-arm, can rotate the radiation source based on a first rotation axis A-A' parallel to the table plane and at least one of the first rotation axis A-A' and the other second rotation axis B-B'. For example, the radiation source can rotate in a plane perpendicular to the first rotation axis A-A' parallel to the table plane, while including the isocenter 111, or in a plane perpendicular to the first rotation axis A-A' and the other second rotation axis B-B', while including the isocenter 111. The second rotation axis B-B' can intersect the first rotation axis A-A', and may be orthogonal to each other at the isocenter 111, for example. For reference, and for the sake of explanation, an example in which the C-arm and radiation source are rotated in a plane is described, but is not limited thereto, and can also rotate simultaneously with two rotation axes A-A' and B-B'. For example, if the first axis of rotation A-A' is parallel to the y-axis, then the radiation source is rotated in the xz-plane perpendicular to the y-axis. For example, if the second axis of rotation B-B' is parallel to the x-axis, then the radiation source can be rotated in the yz-plane perpendicular to the x-axis.

[0034] For example, the electronic device 100 can rotate the C-arm 12 relative to the body 11 around a first rotation axis A-A'. The first rotation axis A-A' represents the axis connecting the point where the C-arm 12 and the body 11 are joined to the isocenter 111. The rotation of the C-arm 12 changes the position of the radiation source 131. For example, the rotation of the C-arm 12 around the first rotation axis A-A' allows the radiation source 131 to rotate in a rotational trajectory on a plane 190 perpendicular to the first rotation axis A-A', while including the isocenter 111. In Figure 2, the XZ plane is shown exemplarily as the plane 190 perpendicular to the first rotation axis A-A'.

[0035] The radiation source 131 can rotate on the plane 190 in a rotational trajectory that is similar in shape to a circle by the rotation of the C-arm 12. The rotational trajectory in which the radiation source 131 moves when the C-arm 12 rotates is not geometrically a perfect circle, and may become a partially distorted circle due to the deflection and vibration of the C-arm 12.

[0036] Furthermore, the electronic device 100 can also rotate the C-arm 12 relative to the body 11 around the second rotation axis B-B'. The second rotation axis B-B' is an axis that intersects (for example, is perpendicular to) the first rotation axis A-A' while passing through the isocenter 111. For example, by the rotation of the C-arm 12 around the second rotation axis B-B', the radiation source 131 can rotate in a rotational trajectory on a plane perpendicular to the second rotation axis B-B' while including the isocenter 111. For reference, Figure 2 shows an example in which the C-arm rotates with respect to the first rotation axis A-A', and the second rotation axis B-B' rotates together with it. However, while the radiation source 131 and the radiation detection unit 14 are located on the Z axis, if rotation of the C-arm 12 occurs with respect to the second rotation axis B-B', the second rotation axis B-B' is parallel to the X axis, and the radiation source 131 can rotate in a rotational trajectory in the YZ plane.

[0037] If the position of the radiation source 131 is changed by the rotation of the C-arm 12, the projection angle 231(θ) of the radiation emitted from the radiation source 131 may be changed. In other words, the projection angle 231 of the radiation emitted from the radiation source may be changed by the rotation of the C-arm 12.

[0038] The radiation projection angle 231 represents the angle between an axis (e.g., the Z-axis) perpendicular to the plane containing the surface of the table 15 and an axis 211 corresponding to the direction of radiation irradiation from the radiation source 131. The direction of radiation irradiation indicates the direction toward the radiation detection unit 14 (or radiation detection sensor) at the radiation irradiation unit 13 (or radiation source 131). The axis 211 corresponding to the direction of radiation irradiation represents the axis connecting the radiation irradiation unit 13 and the radiation detection unit 14. The radiation projection angle 231 is an angle between -180° and 180°.

[0039] The isocenter 111 can be defined in various ways based on the rotation of the C-arm 12. For example, the isocenter 111 indicates a point where radiation irradiated at various positions of the radiation source due to the rotation of the C-arm 12 converges. In a different example, the isocenter 111 may indicate the geometric center of the rotational trajectory of the radiation source 131. In a different example, the isocenter 111 may indicate the rotational center of the C-arm 12.

[0040] Figure 3 illustrates the process by which an electronic device according to one embodiment calculates the physical distance to a target blood vessel from a blood vessel image.

[0041] In one embodiment, a patient 120 can be placed on a tabletop 15-1 of the electronic device 100. The electronic device 100 generates a vascular image 130 including the target blood vessels 320 of the patient 120 using radiation emitted from a radiation source 131.

[0042] The processor 101 of the electronic device 100 acquires a vascular image 130 including the target blood vessel 320, and can derive quantitative analysis results such as the diameter of the target blood vessel 320 and the length of the lesion from the acquired vascular image 130. In order to derive quantitative analysis results regarding the target blood vessel 320 from the vascular image 130, the processor 101 needs to convert the distance measured within the vascular image 130 into real-world physical distances such as μm, mm, and cm. Here, the processor 101 can convert the distance measured within the vascular image 130 into physical distances by utilizing a calibration factor.

[0043] Specifically, the physical distance can be calculated by multiplying the number of pixels corresponding to the distance measured within the vascular image 130 by a calibration coefficient. For example, the physical distance is shown in the following formula (1).

[0044]

number

[0045] Referring to equation (1), the calibration coefficient represents the physical distance corresponding to the length (e.g., horizontal or vertical) of a single pixel that makes up the vascular image 130. To accurately calculate the physical distance, the calibration coefficient must be calculated accurately. The calibration coefficient indicates the spatial relationship between an object in the vascular image and an object in the real world.

[0046] In one embodiment, the electronic device can individually calculate calibration coefficients for each of the multiple blood vessel points included in the target blood vessel 320 in order to accurately calculate the physical distance to the target blood vessel 320. The calibration coefficients for the blood vessel points included in the target blood vessel 320 can be calculated using the distance from the blood vessel point to the radiation source 131. Since the distance to the radiation source 131 differs for each blood vessel point, the calibration coefficients calculated by the electronic device for each of the multiple blood vessel points included in the target blood vessel 320 will differ from one another. The electronic device calculates the calibration coefficient for a blood vessel point in order to calculate the physical distance at that point. For example, the electronic device may calculate the calibration coefficient for a blood vessel point in order to calculate the diameter of that point.

[0047] Figure 4 is a flowchart illustrating the process by which an electronic device according to one embodiment calculates the physical distance at a vascular point included in the target blood vessel.

[0048] In operation 410, the processor of the electronic device acquires a vascular image including the target blood vessel located on the table.

[0049] The radiation irradiation unit of the electronic device (for example, the radiation irradiation unit 13 in Figure 3) irradiates a target blood vessel located on the table with radiation using a radiation source (for example, the radiation source 131 in Figure 3) connected to the C-arm. The target blood vessel includes multiple blood vessel points. For example, each of the multiple blood vessel points included in the target blood vessel is located on the centerline of the target blood vessel. The radiation detection unit of the electronic device (for example, the radiation detection unit 14 in Figure 3) detects the radiation that has passed through the target blood vessel. For example, the processor of the electronic device can use the radiation detected by the radiation detection unit to generate (or acquire) a blood vessel image including the target blood vessel located on the table.

[0050] The electronic device must calculate a calibration factor to determine the physical distance (e.g., the diameter of the vessel) to the target vessel. The calibration factor represents the spatial relationship between an object in the vessel image and an object in the real world. The electronic device may calculate a calibration factor separately for each vessel point included in the target vessel. This is because the electronic device should use the calibration factor for that vessel point to calculate the physical distance at that vessel point in the target vessel. The operation described below is the operation in which the electronic device calculates the calibration factor for one vessel point and then calculates the physical distance at that vessel point.

[0051] Next, in operation 420, the electronic device calculates the target distance from the blood vessel point included in the target blood vessel to the radiation source.

[0052] The electronic device can use a vascular image containing the target vessel to calculate the target distance from the vascular point within the target vessel to the radiation source. Specifically, the electronic device can calculate a preliminary distance from the pixel corresponding to the vascular point within the vascular image containing the target vessel to the radiation source. Using the calculated preliminary distance, the electronic device can calculate the target distance from the vascular point within the target vessel to the radiation source.

[0053] In operation 430, the electronic device calculates a calibration coefficient corresponding to the blood vessel location based on the calculated target distance.

[0054] The calibration coefficient represents the physical distance corresponding to the length of a single pixel (e.g., the width or height of the pixel) that constitutes the vascular image including the target vessel. The electronic device can calculate the calibration coefficient 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 represents the length of a single pixel (e.g., the width or height of the pixel) that constitutes the vascular image.

[0055] In operation 440, the electronic device calculates the physical distance at the blood vessel location using the calculated calibration coefficient.

[0056] The electronic device can derive quantitative analysis results such as the diameter of the vessel and the length of the lesion at specific points within the target vessel. The electronic device can derive these quantitative analysis results using vascular images. The electronic device needs to convert the distances measured within the vascular images into real-world physical distances such as μm, mm, and cm. Here, the electronic device can convert the distances measured within the vascular images into physical distances using calculated calibration coefficients.

[0057] Figure 5 illustrates the process by which an electronic device according to one embodiment calculates calibration coefficients for each of several vascular locations included in the target blood vessel.

[0058] In one embodiment, the electronic device can calculate a calibration coefficient for each of the multiple vascular points included in the target blood vessel.

[0059] First, the electronic device detects radiation transmitted through the target blood vessel 520 through a radiation detection unit (for example, the radiation detection unit 14 in Figure 3), and processes the results from the radiation detection unit to obtain a blood vessel image 540 including the target blood vessel 520. The target blood vessel 520 is, for example, the left coronary artery (LCA) or the right coronary artery (RCA). The target blood vessel 520 may also include the left anterior descending artery (LAD) and the left circumflex artery (LCX) connected to the left coronary artery (LCA). However, the examples of the target blood vessel 520 are not limited to those described above.

[0060] The electronic device can calculate calibration coefficients for each of the multiple vascular points included in the target vessel 520 using the acquired vascular image 540. Here, in order to calculate calibration coefficients for each of the multiple vascular points included in the target vessel 520, it is assumed that the vascular image 540 is placed at the same location as the radiation detection unit. The electronic device can calculate a first calibration coefficient corresponding to the first vascular point in order to calculate the physical distance at the first vascular point included in the target vessel 520. For example, if the target vessel 520 is the right coronary artery, the first vascular point may be the proximal point of the right coronary artery. Similarly, the electronic device can calculate a second calibration coefficient corresponding to the second vascular point in order to calculate the physical distance at the second vascular point included in the target vessel 520. For example, if the target vessel 520 is the right coronary artery, the second vascular point may be the distal point of the right coronary artery. The first and second calibration coefficients may be the same or different. For reference, the first and second vascular points may have different heights in the direction of gravity. For example, a patient (e.g., patient 120 in Figure 3) can be positioned supine on the tabletop (e.g., tabletop 15-1 in Figure 3) of an electronic device (e.g., electronic device 100 in Figure 3). When the patient is positioned supine on the tabletop, the electronic device can acquire a vascular image 540 taken perpendicular to the patient's sagittal plane. In the vascular image 540 taken perpendicular to the patient's sagittal plane, each point of the target vessel 520 may have different heights relative to the direction of gravity. For example, if the target vessel 520 included in the vascular image 540 is the left anterior descending artery and the left circumflex artery, the first vascular point is the proximal point of the left anterior descending artery. In this case, the proximal point of the left anterior descending artery may be located at a height of 170 mm relative to the tabletop. The second vascular point is the distal point of the left circumflex artery. In this case, the distal point of the left circumflex artery may be located at a height of 136 mm relative to the tabletop. In other words, different vascular points within the target vessel 520 may each have different heights relative to the direction of gravity.Therefore, the electronic device can calculate the first and second calibration coefficients, taking into account the different heights of the first and second vessel points.

[0061] The electronic device calculates the distance from the first vessel location to the radiation source 510 in order to calculate the first calibration coefficient corresponding to the first vessel location. The electronic device can also calculate the distance from the pixel 531 corresponding to the first vessel location in the vessel image 540 to the radiation source 510 in order to calculate the distance from the first vessel location to the radiation source 510.

[0062] Similarly, the electronic device can calculate the distance from the second vessel location to the radiation source 510 in order to calculate a second calibration coefficient corresponding to the second vessel location. The electronic device can calculate the distance from the pixel 532 corresponding to the second vessel location in the vessel image 540 to the radiation source 510 in order to calculate the distance from the second vessel location to the radiation source 510.

[0063] Figure 6 illustrates the process by which an electronic device according to one embodiment calculates the target distance from a vascular point included in the target blood vessel to a radiation source.

[0064] In one embodiment, the electronic device can calculate the target distance from a vascular point 631 included in the target blood vessel 620 to the radiation source 610. The electronic device may use a vascular image 640 including the target blood vessel 620 to calculate the target distance from the vascular point 631 to the radiation source 610. To calculate the target distance from a vascular point included in the target blood vessel 620 to the radiation source, it is considered that the vascular image 640 is positioned at the same location as the radiation detection unit.

[0065] In one embodiment, the electronic device can first calculate a preliminary distance Y from the pixel 641 corresponding to the blood vessel point 631 in the blood vessel image 640 containing the target blood vessel 620 to the radiation source 620, in order to calculate the target distance X from the blood vessel point 631 included in the target blood vessel 620 to the radiation source 620. In other words, the electronic device can calculate the target distance X based on the calculated preliminary distance Y. The following describes the process of calculating the preliminary distance Y from the pixel 641 corresponding to the blood vessel point 631 in the blood vessel image 640 to the radiation source 610.

[0066] In one embodiment, the electronic device calculates a first distance d1 from pixel 641 corresponding to a vascular point 631 in the vascular image 640 to a center point 650 in the vascular image 640. The electronic device obtains a second distance SID from the radiation source 610 to the radiation detection unit. The electronic device obtains the second distance SID from the radiation source 610 to the radiation detection unit from DICOM (Digital Imaging and Communications in Medicine) metadata. DICOM is a standard for storing and transmitting data related to images generated by an electronic device. The second distance SID from the radiation source 610 to the radiation detection unit represents the distance from the radiation source 610 to the center point 650 in the vascular image 640.

[0067] In one embodiment, the electronic device can calculate a preliminary distance Y based on a first distance d1 and a second distance SID. The first straight line connecting the radiation source 610 and the center point 650 in the vascular image 640, and the second straight line connecting the center point 650 in the vascular image 640 and the pixel 641 corresponding to the vascular point 631 in the vascular image 640 are orthogonal to each other. Therefore, the electronic device can calculate the preliminary distance Y using the following formula (2).

[0068]

number

[0069] In equation (2), Y is the preliminary distance from pixel 641 corresponding to vascular point 631 in the vascular image 640 to the radiation source 610, d1 is the first distance from pixel 641 corresponding to vascular point 631 in the vascular image 640 to the center point 650 in the vascular image 640, and SID is the second distance from the radiation source 610 to the radiation detector.

[0070] In one embodiment, the electronic device can calculate the target distance X based on the calculated preliminary distance Y. The electronic device calculates 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 represents 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 is located on a straight line connecting the radiation source 610 and the center point 650 in the blood vessel image 640.

[0071] In one embodiment, the electronic device can calculate the target distance X by multiplying the calculated preliminary distance Y by the average distance from the radiation source 610 to the target blood vessel 620, and then dividing the result by the distance SID from the radiation source 610 to the radiation detection unit. In other words, the electronic device can calculate the target distance X using the following formula (3).

[0072]

number

[0073] In equation (3), X is the target distance from vascular point 631 included in the target vessel 620 to the radiation source 610, Y is the preliminary distance from pixel 641 corresponding to vascular point 631 in the vascular image 640 to the radiation source 610, SOD is the average distance from the radiation source 610 to the target vessel 620, and SID is the second distance from the radiation source 610 to the radiation detection unit.

[0074] Figure 7 illustrates the process by which an electronic device according to one embodiment calculates a first distance from a pixel corresponding to a blood vessel location in a blood vessel image to the center point in the blood vessel image.

[0075] In one embodiment, the electronic device can calculate a first distance d1 from a pixel 741 corresponding to a blood vessel location in the blood vessel image 740 to a central point 750 in the blood vessel image 740.

[0076] In one embodiment, the electronic device calculates a first coordinate of a pixel 741 corresponding to a vascular location in the vascular image 740. The electronic device calculates a second coordinate of a center location 750 in the vascular image 740. The electronic device can calculate a first distance d1 using the calculated first coordinate, the calculated second coordinate, and the imager pixel spacing. Here, the imager pixel spacing represents the length of one pixel constituting the vascular image (e.g., horizontal or vertical).

[0077] In one embodiment, the electronic device can obtain size information of the pixel array constituting the vascular image 740 from DICOM metadata. The size information of the pixel array includes the number of rows and columns constituting the pixel array. The electronic device sets the coordinates of the reference point 711 located at the uppermost left end of the vascular image 740 as (0,0). The electronic device can increase the x-coordinate by a value obtained by dividing the distance moved along the first axis 721 relative to the reference point 711 by the width of the pixel. The electronic device can increase the y-coordinate by a value obtained by dividing the distance moved along the second axis 722 relative to the reference point 711 by the height of the pixel.

[0078] The following describes the process for calculating the first coordinates of pixel 741 corresponding to a blood vessel location in blood vessel image 740. First, the electronic device can calculate the center point of the pixel as the pixel's coordinates. The electronic device then calculates the position of pixel 741 corresponding to the blood vessel location. Pixel 741 corresponding to the blood vessel location may be located in 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 pixel 741 corresponding to the blood vessel location as (a-0.5, b-0.5).

[0079] The electronic device calculates the x-coordinate of the central point 750 within the vascular image 740 by dividing the number of columns in the pixel array by 2, and the y-coordinate by dividing the number of rows in the pixel array by 2. For example, if the number of columns and rows in the pixel array is 8 each, the coordinates of the central point 750 within the vascular image 740 can be calculated as (4,4).

[0080] In one embodiment, the electronic device can calculate a first distance d1 using the calculated first coordinate, the calculated second coordinate, and the imager pixel spacing. The electronic device calculates the first distance d1 using the following formula (4).

[0081]

number

[0082] In equation (4), d1 is the first distance from pixel 741, which corresponds to a vascular point in the vascular image 740, to the center point 750 in the vascular image 740, (P x , P y ) is the first coordinate of pixel 741 corresponding to the blood vessel location in blood vessel image 740, (C x , C y ) represents the second coordinate of the central point 750 within the vascular image 740, and IP indicates the imager pixel interval.

[0083] Figure 8 illustrates the process by which an electronic device according to one embodiment calculates the average distance from the radiation source to the target blood vessel.

[0084] The following describes the process by which the electronic device calculates the average distance SOD from the radiation source 13 to the target blood vessel 320. Figure 8 is a side view of the electronic device (for example, the electronic device 100 in Figure 1 as seen from the XZ plane). Before irradiating the target blood vessel 320 with radiation using the radiation source 131, the electronic device can move the tabletop plate 15-1 to align the radiation source 131, the target blood vessel 320, and the isocenter point 111 in a straight line. In other words, the blood vessel image including the target blood vessel 320 (for example, the blood vessel image 540 in Figure 5, the blood vessel image 640 in Figure 6, and the blood vessel image 740 in Figure 7) may be an image acquired when the radiation source 131, the target blood vessel 320, and the isocenter point 111 are arranged in a straight line.

[0085] JPEG2026530059000006.jpg65170

[0086] In summary, the average distance from radiation source 131 to target blood vessel 320 can be calculated using the following formula (5).

[0087]

number

[0088] In the above formula (5), SOD is the average distance from radiation source 131 to target vessel 320, Source to Isocenter is the straight-line distance d3 from radiation source 131 to isocenter point 111, Isocenter to table is the vertical distance d1 from isocenter point 111 to table 15, Object height is the vertical distance d2 from target vessel 320 to table 15, and θ represents the radiation irradiation angle.

[0089] Figure 9 illustrates the process by which an electronic device according to one embodiment calculates the physical distance at a vascular point 930 included in the target blood vessel.

[0090] In one embodiment, the electronic device calculates a calibration coefficient corresponding to a vascular point 930 included in the target blood vessel 920. The electronic device can calculate the calibration coefficient corresponding to a vascular point 930 by multiplying the value obtained by dividing the target distance from the vascular 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 detection unit by the imager pixel interval IP. That is, the calibration coefficient corresponding to a vascular point 930 included in the target blood vessel 920 is shown in the following formula (6).

[0091]

number

[0092] In equation (6), SID represents the second distance from the radiation source to the radiation detector, and IP represents the imager pixel spacing. The distance SID from the radiation source to the radiation detector and the imager pixel spacing IP can be extracted from DICOM (Digital Imaging and Communications in Medicine) metadata.

[0093] In one embodiment, the electronic device calculates a calibration coefficient corresponding to a vascular point 930 included in the target blood vessel 920, and uses the calculated calibration coefficient to convert the distance measured in the blood vessel image 940 into a physical distance in actual space. The electronic device calculates the physical distance at vascular point 930 using the calibration coefficient corresponding to vascular point 930. Here, the physical distance at vascular point 930 represents the physical distance to the blood vessels near vascular point 930.

[0094] For example, an electronic device can calculate the physical distance corresponding to the diameter of a blood vessel at blood vessel point 930 by multiplying the calibration coefficient corresponding to blood vessel point 930 by the number of pixels corresponding to the diameter of the blood vessel at blood vessel point 930 as shown in the blood vessel image 940. In a different example, the electronic device may detect a lesion from blood vessel point 930. In this case, the electronic device can also calculate the physical distance corresponding to the length of the lesion shown at blood vessel point 930 by multiplying the calibration coefficient corresponding to blood vessel point 930 by the number of pixels corresponding to the length of the lesion at blood vessel point 930 as shown in the blood vessel image 940. In addition, the electronic device can use the calibration coefficient corresponding to blood vessel point 930 to derive various quantitative analysis results regarding blood vessel point 930 within the blood vessel image 940.

[0095] Referring to Figure 9, the electronic device can label the boundary of the target vessel 920 in a vascular image 940 that includes the target vessel 920, and after labeling, estimate the vessel diameter at one vessel point 930 included in the centerline 921 of the target vessel 920. For example, the electronic device may generate a line segment 950 at vessel point 930 that is perpendicular to the centerline 921 of the target vessel but does not deviate from the boundary of the target vessel 920. The electronic device can measure the number of pixels (e.g., 20.9) shown in the generated line segment 950. By multiplying the measured number of pixels (e.g., 20.9) by a calibration coefficient corresponding to vessel point 930, the electronic device can estimate the vessel diameter (e.g., 1.9 mm) at vessel point 930.

[0096] The embodiments described above can be embodied in hardware components, software components, and / or combinations of hardware and software components. For example, the adaptive supersampling apparatus, method, and components described in the embodiments can be embodied using a general-purpose computer or a special-purpose computer, such as a processor, controller, ALU (arithmetic logic unit), digital signal processor, microcomputer, FPGA (Field Programmable Gate Array), PLU (Programmable Logic Unit), microprocessor, or other device capable of executing and responding to commands. The processing apparatus can execute an operating system (OS) and software applications that run on the OS. The processing apparatus may also access, store, manipulate, process, and generate data in response to the execution of the software. For convenience of understanding, it has sometimes been described that one processing apparatus is used, but a person with ordinary skill in the art will see that the processing apparatus may include multiple processing elements and / or multiple types of processing elements. For example, a processing adaptive supersampling apparatus may include multiple processors or one processor and one controller. Furthermore, other processing configurations, such as parallel processors, are also possible.

[0097] Software may include computer programs, code, instructions, or any combination thereof, which can configure or instruct a processing unit independently or collectively as desired. Software and / or data may be interpreted by a processing adaptive supersampling device or permanently embodied in any type of machine, component, physical device, virtual device, computer storage medium or device, or transmitted signal wave for the purpose of providing instructions or data to a processing adaptive supersampling device. Software may be distributed across a networked computer system and stored or executed in a distributed manner. Software and data may be stored on computer-readable recording media.

[0098] The method according to this embodiment is embodied in the form of program instructions that are implemented via various computer means and recorded on a computer-readable recording medium. The recording medium includes program instructions, data files, data structures, etc., individually or in combination. The recording medium and program instructions may be specifically designed and configured for the purposes of the present invention, or they may be known and usable by those skilled in the art who have technology in the field of computer software. Examples of computer-readable recording media include magnetic media such as hard disks, floppy disks and magnetic tapes, optical recording media such as CD-ROMs and DVDs, magneto-optical media such as floppy disks, and hardware devices specifically configured to store and execute program instructions, such as ROMs, RAMs, and flash memory. Examples of program instructions include not only machine code generated by a compiler, but also high-level language code executed by a computer using an interpreter or the like.

[0099] The hardware device described above may be configured to operate as one or more software models to perform the operations shown in the present invention, and vice versa.

[0100] As described above, although embodiments have been illustrated with limited drawings, a person with ordinary skill in the art can apply various technical modifications and variations based on the above description. For example, the described technique may be performed in a different order than described, and / or the described system, structure, apparatus, circuit, and other components may be combined or assembled in a different manner than described, or replaced or substituted by other components or equivalents, and still achieve the desired results.

[0101] Therefore, other embodiments, other embodiments, and claims equivalent to those described below also fall within the scope of the claims.

Claims

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

2. The step of calculating the first target distance is: The steps include calculating a preliminary distance from the pixel corresponding to the first vessel location in the acquired vessel image to the radiation source, A step of calculating the first target distance based on the calculated preliminary distance, The blood vessel image processing method according to claim 1, including the method described in claim 1.

3. The step of calculating the aforementioned reserve distance is: The steps include: calculating a first distance from the pixel corresponding to the first vessel location in the acquired vessel image to the center point in the vessel image; 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, The blood vessel image processing method according to claim 2, including the method described in claim 2.

4. The blood vessel image processing method according to claim 3, wherein the distance from the radiation source to the radiation detection unit indicates the distance from the radiation source to the central point in the blood vessel image.

5. The step of calculating the first target distance based on the aforementioned preliminary distance is: A step of calculating the average distance from the radiation source to the target blood vessel, The first target distance is calculated by multiplying the calculated preliminary distance by the average distance from the radiation source to the target blood vessel, and then dividing the result by the distance from the radiation source to the radiation detection unit. The blood vessel image processing method according to claim 2, including the method described in claim 2.

6. The step of calculating the first distance is: The steps include calculating the first coordinates of the pixels corresponding to the first vessel location in the acquired vessel image, The steps include calculating the second coordinates of the central point within the acquired vascular image, A step of calculating the first distance using the first coordinate calculated above, the second coordinate calculated above, and the imager pixel interval, The blood vessel image processing method according to claim 3, including the method described in claim 3.

7. The blood vessel image processing method according to claim 5, wherein the step of calculating the average distance from the radiation source to the target blood vessel includes the step of calculating the average distance from the radiation source to the target blood vessel based on a first vertical distance from the isocenter point of a C-arm connected to the radiation source to the table, and a second vertical distance from the target blood vessel to the table.

8. The vascular image processing method according to claim 7, wherein the isocenter is the center of the rotational trajectory of the radiation source generated by the rotation of the C-arm.

9. The blood vessel image processing method according to claim 7, wherein the acquired blood vessel image is an image of a blood vessel acquired while the radiation source, the target blood vessel, and the isocenter point are arranged in a straight line.

10. The blood vessel image processing method according to claim 1, wherein the step of calculating the first calibration coefficient corresponding to the first blood vessel location includes the step of calculating the first calibration coefficient corresponding to the first blood vessel location using a value obtained by multiplying the value obtained by dividing the calculated first target distance by the distance from the radiation source to the radiation detection unit by the imager pixel interval.

11. The blood vessel image processing method according to claim 1, wherein the step of calculating a first physical distance at the first blood vessel location includes the step of calculating a first physical distance corresponding to the blood vessel diameter at the first blood vessel location by multiplying a first calibration coefficient corresponding to the first blood vessel location by the number of pixels corresponding to the blood vessel diameter at the first blood vessel location shown in the blood vessel image.

12. A step of calculating a second target distance from a second vessel point included in the target vessel to the radiation source, A step of calculating a second calibration coefficient corresponding to the second blood vessel point based on the second target distance calculated above, A step of calculating the second physical distance at the second blood vessel point using the second calibration coefficient, The blood vessel image processing method according to claim 1, further comprising:

13. An electronic device for processing vascular images, A C-arm having an open arc shape, A radiation source connected to the C-arm and positioned on the table to irradiate a target blood vessel with radiation, A processor that acquires a vascular image including the target vascular material, calculates a first target distance from a first vascular point included in the target vascular material to the radiation source, calculates a first calibration coefficient corresponding to the first vascular point based on the calculated first target distance, and calculates a first physical distance at the first vascular point using the calculated first calibration coefficient. Electronic devices, including those mentioned above.

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