CN116363243A

CN116363243A - Method, device and storage medium for determining cylindrical projection image of blood vessel

Info

Publication number: CN116363243A
Application number: CN202310250636.0A
Authority: CN
Inventors: 王彬; 张超; 毛益进; 赵清华; 王纯亮
Original assignee: Tianjin Yuanjing Technology Service Co ltd
Current assignee: Tianjin Yuanjing Technology Service Co ltd
Priority date: 2023-03-15
Filing date: 2023-03-15
Publication date: 2023-06-30

Abstract

The invention provides a method, a device and a storage medium for determining cylindrical projection images of blood vessels, wherein the method comprises the following steps: acquiring a blood vessel center line point set and medical image data of a target blood vessel; calculating a first center point and a second center point which are farthest from the center line point of the blood vessel; calculating the volume parameters of the vessel cylinder corresponding to the target vessel according to the first center point and the second center point; calculating the radius of a cylindrical projection surface of the blood vessel according to the volume parameter; determining an intersection point of the measured ray and the radius of the projection surface; calculating voxel values of the intersection points according to the coordinates of the intersection points; and determining a cylindrical projection image of the blood vessel according to the voxel value of the intersection point. Therefore, the cylindrical projection image of the target blood vessel can be calculated by automatically utilizing the blood vessel center line point set and the medical image data of the target blood vessel, the deformation of the target blood vessel can be reduced to the greatest extent, a doctor can conveniently and accurately grasp the lesion information of the target blood vessel by utilizing the cylindrical projection image of the blood vessel, and the doctor is assisted in processing the target blood vessel.

Description

Method, device and storage medium for determining cylindrical projection image of blood vessel

Technical Field

The present invention relates to image simulation technology, and in particular, to a method and apparatus for determining a cylindrical projection image of a blood vessel, and a storage medium.

Background

Vascular disease has become one of the most important public health problems, and the segmentation of blood vessels from them is a key step toward accurate visualization, diagnosis and quantitative analysis of vascular lesions, in the face of angiographic images of specific size and complexity. The blood vessels at different parts of the human body can provide a great deal of information of relevant tissues of the human body, and the forms (mainly including the diameter of the blood vessels, the bifurcation angle of the blood vessels and the curvature of the blood vessels) and the distribution of the blood vessels are all important indexes for diagnosing relevant vascular diseases. The accurate visualization and accurate quantification of human blood vessels is of great importance for the diagnosis and treatment of vascular diseases, becoming an important prerequisite for many clinical practices. The degree of stenosis of a blood vessel is an important indicator of the severity of vascular disease, as it determines the particular treatment regimen that follows. There is a need for an excellent performance intra-operative navigation system, both for interventional procedures and bypass procedures, that can help surgeons better view three-dimensional vascular structures. The above clinical requirements provide great challenges for the integrity and accuracy of three-dimensional vessel segmentation technology, and at present, various vessel imaging technologies have been applied to clinical practice, such as Digital Subtraction Angiography (DSA), CT angiography (CTA), nuclear Magnetic Resonance Angiography (MRA), etc., but when the conventional technology is used for simulating vessels, angiography is usually used, and since angiography images are two-dimensional images, the projection positions of the angiography images are limited, morphological characteristics of lesion vessels cannot be comprehensively displayed, and meanwhile, for small vessel branch tips with smaller diameters and vessels penetrating through cortex and lesion tumors, the calculated vessel cylindrical projection cannot accurately display the branch tips of the small vessels and vessels penetrating through cortex and lesion tumors due to larger bending rate, so that accurate judgment of doctors is affected.

Disclosure of Invention

In view of this, embodiments of the present invention provide a method, an apparatus, an electronic device, a software program, and a storage medium for determining a cylindrical projection image of a blood vessel, which can automatically use a blood vessel centerline point set of a target blood vessel and medical image data to calculate a cylindrical projection image of the blood vessel, so as to reduce deformation of the target blood vessel to the greatest extent, and facilitate a doctor to accurately grasp lesion information of the target blood vessel by using the cylindrical projection image of the blood vessel, and assist the doctor in processing the target blood vessel.

The technical scheme of the embodiment of the invention is realized as follows:

the embodiment of the invention provides a method for determining a cylindrical projection image of a blood vessel, which comprises the following steps:

acquiring a blood vessel center line point set and medical image data of a target blood vessel;

calculating a first center point and a second center point which are farthest from the center line point of the blood vessel;

calculating the volume parameters of the vessel cylinder corresponding to the target vessel according to the first center point and the second center point;

calculating the radius of the cylindrical projection surface of the blood vessel according to the volume parameter;

determining an intersection point of a measured ray and the projection surface radius;

according to the coordinates of the intersection points, calculating voxel values of the intersection points;

And determining a cylindrical projection image of the blood vessel according to the voxel value of the intersection point.

The embodiment of the invention also provides a cylindrical projection image determining device of the blood vessel, which comprises:

the signal transmission module is used for acquiring a blood vessel central line point set of a target blood vessel and medical image data;

the signal processing module is used for calculating a first center point and a second center point which are farthest from the center line point of the blood vessel;

the signal processing module is used for calculating the volume parameter of the vessel cylinder corresponding to the target vessel according to the first center point and the second center point;

the signal processing module is used for calculating the radius of the cylindrical projection surface of the blood vessel according to the volume parameter;

the signal processing module is used for determining an intersection point of the measured ray and the radius of the projection surface;

the signal processing module is used for calculating the voxel value of the intersection point according to the coordinates of the intersection point;

and the signal processing module is used for determining a cylindrical projection image of the blood vessel according to the voxel value of the intersection point.

In the above-mentioned scheme, the signal processing module is configured to calculate a distance between each center point in the blood vessel center line point set;

The signal processing module is used for screening two center points farthest from each other as the first center point and the second center point.

In the above scheme, the signal processing module is configured to calculate, according to the first center point and the second center point, a center line of the vessel cylinder and a center line vector corresponding to the center line;

the signal processing module is used for determining a distance set and a drop foot set from each central point in the blood vessel central line point set to the central line of the blood vessel cylinder;

the signal processing module is used for calculating a maximum distance value and a minimum distance value in the distance set;

the signal processing module is used for calculating the distance between adjacent drop feet in the drop foot set and determining a first drop foot and a second drop foot with the largest distance.

In the above scheme, the signal processing module is configured to determine a top surface of the vessel cylinder according to the first drop foot and the centerline vector;

the signal processing module is used for determining the bottom surface of the blood vessel cylinder according to the second drop foot and the central line vector;

the signal processing module is used for determining the outer diameter of the blood vessel cylinder according to the maximum distance value;

The signal processing module is used for determining the inner diameter of the vessel cylinder according to the minimum distance value;

the signal processing module is used for calculating the radius of the cylindrical projection surface of the blood vessel according to the outer diameter of the blood vessel cylinder and the inner diameter of the blood vessel cylinder.

In the above scheme, the signal processing module is configured to determine an included angle of the measurement ray according to a display requirement of the target blood vessel;

the signal processing module is used for determining a measured ray set in the top surface of the blood vessel cylinder by taking the central line of the blood vessel cylinder as the center according to the included angle of the measured rays;

the signal processing module is used for calculating the intersection point of each measuring ray in the measuring ray set and the radius of the projection surface according to the scattering direction of each measuring ray in the measuring ray set.

In the above scheme, the signal processing module is configured to determine coordinates of an intersection point of each measurement ray in the measurement ray set and the radius of the projection surface;

the signal processing module is used for determining the minimum pixel distance of the medical image data;

according to the coordinates of the intersection point, the minimum pixel distance and the scattering direction of each measured ray, calculating a voxel value corresponding to each central point between the maximum distance value and the minimum distance value;

And the signal processing module is used for screening the maximum voxel value from the voxel values corresponding to each central point as the voxel value of the intersection point.

In the above scheme, the signal processing module is configured to determine a pixel interval from a top surface of the vessel cylinder to a bottom surface of the vessel cylinder;

the signal processing module is used for dividing the vessel cylinder according to the pixel spacing to obtain vessel cylinders of different levels;

the signal processing module is used for determining a measured ray set in each level of blood vessel cylinder by taking the central line of the blood vessel cylinder as the center according to the included angle of the measured rays;

the signal processing module is used for calculating the intersection point of each measuring ray in the vessel cylinder of each level and the radius of the projection surface according to the scattering direction of each measuring ray in the measuring ray set.

In the above scheme, the signal processing module is configured to determine, in a vessel cylinder of each level, coordinates of an intersection point of each measurement ray and the radius of the projection plane;

the signal processing module is used for calculating a voxel value corresponding to each central point between the maximum distance value and the minimum distance value in the vessel cylinder of each level according to the coordinate of the intersection point, the minimum pixel distance and the scattering direction of each measured ray;

And the signal processing module is used for screening the maximum voxel value from the voxel values corresponding to each central point as the voxel value of the intersection point in the vessel cylinder of each level.

The embodiment of the invention also provides electronic equipment, which is characterized by comprising:

a memory for storing executable instructions;

and the processor is used for realizing the cylindrical projection image determining method of the blood vessel when executing the executable instructions stored in the memory.

The embodiment of the invention also provides a computer readable storage medium which stores executable instructions, and is characterized in that the executable instructions realize the method for determining the cylindrical projection image of the blood vessel when being executed by a processor.

Drawings

FIG. 1 is a schematic view of a usage scenario of a method for determining a cylindrical projection image of a blood vessel according to an embodiment of the present invention;

fig. 2 is a schematic diagram of a composition structure of a cylindrical projection image determining apparatus for a blood vessel according to an embodiment of the present invention;

FIG. 3 is a schematic diagram showing an alternative process for determining a cylindrical projection image of a blood vessel in accordance with an embodiment of the present invention;

FIG. 4A is a schematic diagram of a centerline point set according to an embodiment of the present invention;

FIG. 4B is a schematic view of a vessel cylinder projection of a centerline point set according to an embodiment of the present invention;

FIG. 5 is a schematic view of a computing scene of 2-segment vessel cylindrical projection in an embodiment of the invention;

FIG. 6 is a schematic diagram of a process for calculating volumetric parameters of a vessel cylinder according to an embodiment of the present invention;

FIG. 7 is a schematic view of a cylindrical projection surface radius of a blood vessel according to an embodiment of the present invention;

FIG. 8 is a schematic diagram of the intersection of a measured ray with a projection surface radius in an embodiment of the invention;

FIG. 9 is a schematic diagram of determining a cylindrical projection image of a blood vessel according to voxel values of intersection points in an embodiment of the invention;

FIG. 10 is a schematic diagram of a process for determining a cylindrical projection image of a blood vessel in an embodiment of the present invention;

fig. 11 is a cylindrical projection image of a coronary vessel in an embodiment of the present invention.

Detailed Description

The present invention will be further described in detail with reference to the accompanying drawings, for the purpose of making the objects, technical solutions and advantages of the present invention more apparent, and the described embodiments should not be construed as limiting the present invention, and all other embodiments obtained by those skilled in the art without making any inventive effort are within the scope of the present invention.

In the following description, reference is made to "some embodiments" which describe a subset of all possible embodiments, but it is to be understood that "some embodiments" can be the same subset or different subsets of all possible embodiments and can be combined with one another without conflict.

Before describing embodiments of the present invention in further detail, the terms and terminology involved in the embodiments of the present invention will be described, and the terms and terminology involved in the embodiments of the present invention will be used in the following explanation.

1) In response to a condition or state that is used to represent the condition or state upon which the performed operation depends, the performed operation or operations may be in real-time or with a set delay when the condition or state upon which it depends is satisfied; without being specifically described, there is no limitation in the execution sequence of the plurality of operations performed.

2) Based on the conditions or states that are used to represent the operations that are being performed, one or more of the operations that are being performed may be in real-time or with a set delay when the conditions or states that are being relied upon are satisfied; without being specifically described, there is no limitation in the execution sequence of the plurality of operations performed.

3) Cloud technology (Cloud technology) refers to a hosting technology for integrating hardware, software, network and other series resources in a wide area network or a local area network to realize calculation, storage, processing and sharing of data. The cloud computing business model application-based network technology, information technology, integration technology, management platform technology, application technology and the like can be collectively called to form a resource pool, and the resource pool is flexible and convenient as required. Cloud computing technology will become an important support. Background services of technical networking systems require a large amount of computing, storage resources, such as video websites, picture-like websites, and more portals. Along with the high development and application of the internet industry, each article possibly has an own identification mark in the future, the identification mark needs to be transmitted to a background system for logic processing, data with different levels can be processed separately, and various industry data needs strong system rear shield support and can be realized only through cloud computing.

4) Cylindrical projection: a group of blood vessels cannot be unfolded into a plane in space, a cylindrical surface can be unfolded into a plane, and projection transformation of a group of blood vessels is realized by projecting a central line to the cylindrical surface and then unfolding the cylindrical surface.

In describing the method for determining a cylindrical projection image of a blood vessel provided in the present application, a defect in the related art will be briefly described with reference to an implementation environment shown in fig. 1, where fig. 1 is a schematic view of a usage scenario of the method for determining a cylindrical projection image of a blood vessel provided in an embodiment of the present invention, and the implementation environment of the present invention may include: a computer device 11 and a blood vessel image acquisition device 12. The computer device 11 and the blood vessel image-capturing device 12 may be directly or indirectly connected by wired or wireless communication. The obtained cylindrical projection image of the blood vessel can be stored in the server 200, so that the medical staff can conveniently take the image for use.

The blood vessel image acquisition device 12 is used for acquiring images of blood vessels, and then the acquired blood vessel images are sent to the computer device 11, and the computer device 11 constructs a three-dimensional blood vessel model according to the blood vessel images. The image acquisition device 12 may be, for example, a DSA device for subtracting an angiographic blood vessel image from an un-angiographic blood vessel image to obtain a blood vessel image with structures other than blood vessels removed, or a coronary CT image processing system with a projection image calculation function for determining a cylindrical projection image of blood vessels of a coronary of a target object.

The computer device 11 may be a terminal or a server, for example. Alternatively, the terminal may be any electronic product that can perform man-machine interaction with a user through one or more modes of a keyboard, a touch pad, a touch screen, a remote controller, a voice interaction or handwriting device, such as a PC (Personal Computer, a personal computer), a mobile phone, a smart phone, a PDA (Personal Digital Assistant, a personal digital assistant), a wearable device, a PPC (Pocket PC, palm computer), a tablet computer, a smart car machine, a smart television, a smart sound box, a car terminal, and the like. The server may be a server, a server cluster comprising a plurality of servers, or a cloud computing service center.

In some embodiments, the computer device 11 and the vessel image acquisition device 12 may be integrated so that the acquisition of the vessel image and the cylindrical projection image determination of the vessel can be implemented on one device.

It should be understood by those skilled in the art that the above-mentioned computer device 11 and blood vessel image acquisition device 12 are only examples, and other computer devices and blood vessel image acquisition devices that may be present in the present invention or may be present in the future are applicable to the present application and should be included in the scope of the present application, which is not limited in particular.

The cylindrical projection image determining method of the blood vessel can be applied to any scene needing to construct a three-dimensional blood vessel model, for example: 1) The coronary artery CT image reconstruction method is applied to a coronary artery CT image processing system, image reconstruction and analysis are carried out based on coronary artery CTA images, the coronary artery stenosis, the myocardial bridge and the stent positions and the data thereof are automatically positioned by utilizing the determined cylindrical projection images of the blood vessels, the time for manually reconstructing the coronary artery by a user is saved, and the coronary artery image diagnosis efficiency is improved; 2) The method is applied to a coronary CT image processing system, image reconstruction and fractional flow reserve calculation are carried out on coronary blood vessels based on coronary CTA images, and the determined cylindrical projection images of the blood vessels can be rapidly and accurately reconstructed in three dimensions and the FFR value of the full coronary tree can be accurately calculated. 3) The method is applied to a coronary CT image processing system, in a coronary angiography operation or PCI operation, the obtained coronary DSA coronary tree can be quickly and accurately reconstructed in three dimensions by utilizing the determined cylindrical projection image of the blood vessel, the stenosis position can be accurately positioned, coronary morphology data can be provided for doctors, and references can be given to the condition of the coronary lumen; the determined cylindrical projection image of the blood vessel is used for providing various coronary artery functional data, and quantitative analysis is given to myocardial ischemia degree. 4) Through the data processing of CT images, multidimensional blood vessel reconstruction images are provided for clinical diagnosis and treatment decisions, and quantifiable blood vessel morphology data analysis is output. Such as automated determination of stenosis or prediction of aneurysm location.

The method can be applied to reconstructing a three-dimensional blood vessel model according to two blood vessel images obtained by image acquisition of the same blood vessel at two different angles by using a DSA device, so as to facilitate further research on the blood vessel according to the reconstructed three-dimensional blood vessel model. DSA is a technology for obtaining obvious blood vessel images through subtraction, enhancement and other technologies, has important significance for diagnosing lesions in blood vessels, is commonly used for diagnosing cardiovascular and cerebrovascular stenosis and the like, but because the DSA equipment outputs two-dimensional blood vessel images, the two-dimensional blood vessel images provide limited information, and thus morphological characteristics of the lesion blood vessels cannot be displayed in an omnibearing manner.

The embodiment of the invention can be realized by combining Cloud technology, wherein Cloud technology (Cloud technology) refers to a hosting technology for integrating hardware, software, network and other series resources in a wide area network or a local area network to realize calculation, storage, processing and sharing of data, and can also be understood as the general term of network technology, information technology, integration technology, management platform technology, application technology and the like applied based on a Cloud computing business model. Background services of technical network systems require a large amount of computing and storage resources, such as video websites, picture websites and more portal websites, so cloud technologies need to be supported by cloud computing.

It should be noted that cloud computing is a computing mode, which distributes computing tasks on a resource pool formed by a large number of computers, so that various application systems can acquire computing power, storage space and information service as required. The network that provides the resources is referred to as the "cloud". Resources in the cloud are infinitely expandable in the sense of users, and can be acquired at any time, used as needed, expanded at any time and paid for use as needed. As a basic capability provider of cloud computing, a cloud computing resource pool platform, referred to as a cloud platform for short, is generally called infrastructure as a service (IaaS, infrastructure as a Service), and multiple types of virtual resources are deployed in the resource pool for external clients to select for use. The cloud computing resource pool mainly comprises: computing devices (which may be virtualized machines, including operating systems), storage devices, and network devices.

Referring to fig. 1, the method for determining a cylindrical projection image of a blood vessel according to the embodiment of the present invention may be implemented by a corresponding cloud device, for example: the terminals (including the terminal 10-1 and the terminal 10-2) are connected to the server 200 located at the cloud through the network 300, and the network 300 may be a wide area network or a local area network, or a combination of the two. It should be noted that the server 200 may be a physical device or a virtualized device.

Specifically, as shown in fig. 1 in the foregoing embodiment, the server 200 may be an independent physical server, or may be a server cluster or a distributed system formed by a plurality of physical servers, or may be a cloud server that provides cloud services, cloud databases, cloud computing, cloud functions, cloud storage, network services, cloud communication, middleware services, domain name services, security services, CDNs, and basic cloud computing services such as big data and artificial intelligence platforms. The terminal may be, but is not limited to, a smart phone, a tablet computer, a notebook computer, a desktop computer, a medical device that can perform parameter recording, and the like. The terminal and the server may be directly or indirectly connected through wired or wireless communication, which is not limited herein.

The following describes the structure of the electronic device according to the embodiment of the present invention in detail, and the electronic device may be implemented in various forms, such as a dedicated robot with a stent implantation simulation function, or a robotic arm with a stent implantation simulation function, for example, the server 200 in fig. 1. Fig. 2 is a schematic diagram of a composition structure of an electronic device according to an embodiment of the present invention, and it is understood that fig. 2 only shows an exemplary structure of the electronic device, but not all the structures, and a part of or all the structures shown in fig. 2 may be implemented as required.

The electronic equipment provided by the embodiment of the invention comprises: at least one processor 201, a memory 202, a user interface 203, and at least one network interface 204. The various components in the electronic device 20 are coupled together by a bus system 205. It is understood that the bus system 205 is used to enable connected communications between these components. The bus system 205 includes a power bus, a control bus, and a status signal bus in addition to the data bus. But for clarity of illustration the various buses are labeled as bus system 205 in fig. 2.

The user interface 203 may include, among other things, a display, keyboard, mouse, trackball, click wheel, keys, buttons, touch pad, or touch screen, etc.

It will be appreciated that the memory 202 may be either volatile memory or nonvolatile memory, and may include both volatile and nonvolatile memory. The memory 202 in embodiments of the present invention is capable of storing data to support operation of the terminal (e.g., 10-1). Examples of such data include: any computer program, such as an operating system and application programs, for operation on the terminal (e.g., 10-1). The operating system includes various system programs, such as a framework layer, a core library layer, a driver layer, and the like, for implementing various basic services and processing hardware-based tasks. The application may comprise various applications.

In some embodiments, the apparatus for determining a cylindrical projection image of a blood vessel according to the embodiments of the present invention may be implemented by combining software and hardware, and as an example, the apparatus for determining a cylindrical projection image of a blood vessel according to the embodiments of the present invention may be a processor in the form of a hardware decoding processor, which is programmed to perform the method for determining a cylindrical projection image of a blood vessel according to the embodiments of the present invention. For example, a processor in the form of a hardware decoding processor may employ one or more application specific integrated circuits (ASICs, application Specific Integrated Circuit), DSPs, programmable logic devices (PLDs, programmable Logic Device), complex programmable logic devices (CPLDs, complex Programmable Logic Device), field programmable gate arrays (FPGAs, field-Programmable Gate Array), or other electronic components.

As an example of implementation of the cylindrical projection image determining apparatus for a blood vessel provided by the embodiment of the present invention by combining software and hardware, the cylindrical projection image determining apparatus for a blood vessel provided by the embodiment of the present invention may be directly embodied as a combination of software modules executed by the processor 201, the software modules may be located in a storage medium, the storage medium is located in the memory 202, and the processor 201 reads executable instructions included in the software modules in the memory 202, and performs the cylindrical projection image determining method for a blood vessel provided by the embodiment of the present invention in combination with necessary hardware (including, for example, the processor 201 and other components connected to the bus 205).

By way of example, the processor 201 may be an integrated circuit chip having signal processing capabilities such as a general purpose processor, such as a microprocessor or any conventional processor, a digital signal processor (DSP, digital Signal Processor), or other programmable logic device, discrete gate or transistor logic device, discrete hardware components, or the like.

As an example of implementation of the apparatus for determining a cylindrical projection image of a blood vessel provided by the embodiment of the present invention by hardware, the apparatus provided by the embodiment of the present invention may be implemented directly by the processor 201 in the form of a hardware decoding processor, for example, by one or more application specific integrated circuits (ASIC, application Specific Integrated Circuit), DSPs, programmable logic devices (PLD, programmable Logic Device), complex programmable logic devices (CPLD, complex Programmable Logic Device), field programmable gate arrays (FPGA, field-Programmable Gate Array), or other electronic components.

The memory 202 in embodiments of the present invention is used to store various types of data to support the operation of the electronic device 20. Examples of such data include: any executable instructions, such as executable instructions, for operation on the electronic device 20, a program implementing the method of determining a cylindrical projection image of a blood vessel from an embodiment of the present invention may be included in the executable instructions.

In other embodiments, the apparatus for determining a cylindrical projection image of a blood vessel according to the embodiments of the present invention may be implemented in software, and fig. 2 shows a cylindrical projection image determining apparatus 2020 for a blood vessel stored in a memory 202, which may be software in the form of a program, a plug-in unit, etc., and includes a series of modules, and as an example of the program stored in the memory 202, may include the apparatus for determining a cylindrical projection image of a blood vessel 2020, where the apparatus for determining a cylindrical projection image of a blood vessel 2020 includes the following software modules:

the signal transmission module 2081 is used for acquiring a geometric model of the balloon and a first geometric model of the coronary stent.

The signal transmission module 2081 is configured to acquire a mask image of plaque in coronary artery and a coronary vessel image.

The signal processing module 2082 is configured to perform a particulation process on the geometric model of the balloon, the mask image of the plaque of the first geometric model of the coronary stent, and the coronary vessel image, so as to obtain simulated particles.

In the above scheme, the signal processing module is used for calculating the distance between each center point in the blood vessel center line point set;

and the signal processing module is used for screening the two center points farthest from the signal processing module as a first center point and a second center point.

and the signal processing module is used for calculating the distance between adjacent drop feet in the drop foot set and determining a first drop foot and a second drop foot with the largest distance.

In the above scheme, the signal processing module is used for determining the top surface of the vessel cylinder according to the first drop foot and the central line vector;

the signal processing module is used for determining the bottom surface of the blood vessel cylinder according to the second foot drop and the central line vector;

the signal processing module is used for determining the inner diameter of the blood vessel cylinder according to the minimum distance value;

and the signal processing module is used for calculating the radius of the cylindrical projection surface of the blood vessel according to the outer diameter of the blood vessel cylinder and the inner diameter of the blood vessel cylinder.

In the above scheme, the signal processing module is used for determining the included angle of the measurement rays according to the display requirement of the target blood vessel;

and the signal processing module is used for calculating the intersection point of each measuring ray in the measuring ray set and the radius of the projection surface according to the scattering direction of each measuring ray in the measuring ray set.

In the above scheme, the signal processing module is configured to determine coordinates of an intersection point of each measurement ray in the measurement ray set and a radius of the projection plane;

a signal processing module for determining a minimum pixel pitch of the medical image data;

In the above scheme, the signal processing module is used for determining the pixel interval from the top surface of the vessel cylinder to the bottom surface of the vessel cylinder;

The signal processing module is used for determining a measured ray set in the blood vessel cylinder of each level by taking the central line of the blood vessel cylinder as the center according to the included angle of the measured rays;

and the signal processing module is used for calculating the intersection point of each measured ray in the vessel cylinder of each level and the radius of the projection surface according to the scattering direction of each measured ray in the measured ray set.

In the above scheme, the signal processing module is configured to determine, in the vessel cylinder of each level, coordinates of an intersection point of each measurement ray and a radius of the projection plane;

the signal processing module is used for calculating a voxel value corresponding to each central point between a maximum distance value and a minimum distance value in the vessel cylinder of each level according to the coordinates of the intersection point, the minimum pixel distance and the scattering direction of each measured ray in the vessel cylinder of each level;

Referring to fig. 3, fig. 3 is an optional flowchart of the method for determining a cylindrical projection image of a blood vessel according to the embodiment of the present invention, and it will be understood that the method for determining a cylindrical projection image of a blood vessel shown in fig. 3 may be applied to study for computer-aided diagnosis of coronary artery disease or to imaging a complex blood vessel in a cerebral artery. The steps shown in fig. 3 may be executed by various electronic devices operating the cylindrical projection image determining apparatus for blood vessels, and may be, for example, a blood vessel morphology data analyzing device such as a blood vessel detecting robot with a coronary blood vessel detecting function, a medical robot arm with a human body checking function, and a stenosis automation judging/aneurysm detecting function. The following is a description of the steps shown in fig. 3.

Step 301: a set of vessel centerline points of a target vessel and medical image data are acquired.

In the embodiment of the present invention, the source of the cylindrical projection image of the blood vessel is not particularly limited, and may be, for example, a cylindrical projection image of a coronary artery blood vessel, a cylindrical projection image of a craniocerebral blood vessel, and a cylindrical projection image of a blood vessel at a specified position. Acquired medical image data (Digital Imaging and Communications in Medicine) conforms to digital imaging and communication standards for medicine, and is an international standard (ISO 12052) for medical images and related information. It defines a medical image format that can be used for data exchange with quality meeting clinical needs, so that cylindrical projection images of blood vessels obtained from the medical image data and the set of vessel centerline points of the target blood vessel can be read and used by medical devices of different manufacturers.

Step 302: a first center point and a second center point are calculated that are most distant from the centerline point of the vessel.

Referring to fig. 4A, fig. 4A is a schematic diagram of a center line point set in an embodiment of the present invention, where a vessel center line may be defined as a line connecting points with equal distances from two ends of a vessel wall in a vessel, that is, a perpendicular line is drawn to the vessel wall through any point on the center line of the vessel, and the distances from the points to the vessel walls at two ends along the perpendicular line are equal. As shown in fig. 4A, taking the coronary vessel 401 as an example, the coronary vessel 401 includes two left and right coronary vessels, wherein the left coronary vessel is 408 and the right coronary vessel is 412; the coronary vessel 401 comprises 3 vessel centerlines, namely

centerlines

402 and 404 of a right coronary vessel 412 and a centerline 409 of a left coronary vessel 408, wherein, taking the left coronary vessel 408 as an example, 403 is a center point of a starting position of the

vessel centerline

409, 410 is a center point of an ending position of the vessel centerline 409, the end point 410 is positioned at the center of a section 411 of the centerline 409, the vessel centerlines 409 of 403 to 410 are composed of a plurality of center points (the number of the center points is determined according to different vessel centerline measuring methods or centerline measuring requirements of different vessels), and the plurality of center points can form a center line point set; 407 and 405 are vessel walls at opposite ends of a vessel centerline 409, respectively, and 406 is any point not on centerline 410.

Referring to fig. 4B, fig. 4B is a schematic view of a vessel cylinder projection of a centerline point set in an embodiment of the present invention, where 1 is a target vessel, 2 is a cylinder projection of the target vessel 1, the cylinder projection 2 may include a plurality of vessel cylinders, each segment of vessel cylinder is a cylinder, in some embodiments of the present invention, taking the centerline point set of a vessel of a coronary artery of fig. 4A as an example, the centerline point set of a vessel of a coronary artery may be a point on a central axis of the coronary artery directly extracted by using a coronary artery skeleton extraction algorithm, and different centerlines of the entire vessel of the coronary artery may be combined into a tree structure, and as an example, when any one of the centerline points in the centerline point set shown in fig. 4A is extracted, a point on the central axis of the coronary artery may be directly extracted by using a three-dimensional centerline extraction algorithm in a script language, as shown in fig. 4B, and a point A, B, C on the central axis of the coronary artery shows three centerline points in the central axis.

In some embodiments of the invention, as shown in connection with fig. 4B, calculating a first center point and a second center point in a set of vessel centerline points may be accomplished by:

calculating a distance between each of the center points in the set of vessel centerline points; the two center points farthest from each other are selected as a first center point and a second center point. Calculating two points with the greatest distance in the center line point set, namely obtaining two points with the greatest distance, taking A, B, C three center points as an example, respectively calculating the distance dAB between A and B, the distance dAC between A and C, and the distance dCB between C and B, and determining that dAB is larger than dAC and dAC is larger than dCB, and screening out the two center points A with the greatest distance as a first center point and B as a second center point. The outline of the target blood vessel can be determined through the A and the B, and the accuracy of the cylindrical projection image of the blood vessel is ensured.

Step 303: and calculating the volume parameters of the vessel cylinder corresponding to the target vessel according to the first center point and the second center point.

Referring to fig. 5, fig. 5 is a schematic view of a calculation scenario of 2-segment vessel cylinder projection in an embodiment of the present invention, and in some embodiments of the present invention, determining a volume parameter of a vessel cylinder required to be acquired when the vessel cylinder projection is determined, where the volume parameter of the vessel cylinder includes: the central line vector, the thickness of the vessel wall and the starting and ending positions of the target vessel, because the coronary vessel shown in fig. 5 has a turning point p1 with curvature exceeding the curvature threshold, the complete vessel cylindrical projection can be obtained after splicing by calculating the projection of each section of the target vessel (vessels a1 and a 2) in fig. 5, and the inaccurate calculation of the vessel cylindrical projection caused by overlarge curvature of the coronary vessel is avoided. Wherein the curvature threshold value is related to the type of the target blood vessel, the curvature threshold value can be set in a corresponding storage medium through a blood vessel cylindrical projection determining device and can be adjusted through a control instruction, the curvature threshold value of the coronary artery blood vessel can be 0.01k (kappa), and for a complex coronary artery, when the turning point of the curvature exceeding 0.01k appears in the coronary artery blood vessel, it is indicated that the structure of the coronary artery blood vessel cannot be displayed by directly performing the blood vessel cylindrical projection, and therefore, the coronary artery blood vessel needs to be split into 2 parts by taking the turning point of the curvature exceeding 0.01k as the center, and the blood vessel cylindrical projection processing is respectively performed.

In some embodiments of the invention, calculating the volumetric parameter of the vessel cylinder from the first center point and the second center point may be accomplished by:

calculating the central line of the vessel cylinder and the central line vector corresponding to the central line according to the first central point and the second central point; determining a distance set and a drop set of each central point in the blood vessel central line point set to the central line of the blood vessel cylinder; calculating a maximum distance value and a minimum distance value in the distance set; and calculating the distance between adjacent drop feet in the drop foot set, and determining a first drop foot and a second drop foot with the largest distance. Referring to fig. 6, fig. 6 is a schematic diagram showing a process of calculating a volume parameter of a vessel cylinder according to an embodiment of the present invention, wherein, in connection with the previous embodiment, for each segment of a target vessel, a spatial straight line L shown in fig. 6, and a straight line vector V can be determined using two points P1 and P2 having the greatest center line point concentration distance, where the straight line L is the center line of the vessel cylinder. From the vessel centerline point set, the distance D and the drop foot T from each centerline point in the vessel centerline point set to the spatial straight line L (the centerline of the vessel cylinder) are calculated, constituting a distance set and a drop foot set. And screening a distance maximum value Dmax and a distance minimum value Dmin in the distance set. After calculating the distance between adjacent feet in the drop foot set, searching two points T1 and T2 with the farthest distances among all points in the drop foot T, for example, 5 drop feet in the drop foot set are respectively T1, T2, T3, T4 and T5, and the distances between the adjacent drop feet are respectively d _T1T2 、d _T2T3 、d _T3T4 、d _T4T5 And determine d _T1T2 At maximum, then T1 is the first drop foot and T2 is the second drop foot.

Step 304: and calculating the radius of the cylindrical projection surface of the blood vessel according to the volume parameter.

Referring to fig. 7, fig. 7 is a schematic diagram of a radius of a cylindrical projection surface of a blood vessel according to an embodiment of the present invention, wherein a difference between an outer diameter of the blood vessel cylinder and an inner diameter of the blood vessel cylinder is calculated due to a thickness of a blood vessel wall, so as to obtain the radius of the cylindrical projection surface of the blood vessel. Specifically, calculating the cylindrical projection surface radius of the blood vessel according to the volume parameter can be realized by the following ways: determining the top surface of the vessel cylinder according to the first drop foot and the central line vector; determining the bottom surface of the vessel cylinder according to the second drop foot and the central line vector; determining the outer diameter of the vessel cylinder according to the maximum distance value; determining the inner diameter of the vessel cylinder according to the minimum distance value; and calculating the difference between the outer diameter of the vessel cylinder and the inner diameter of the vessel cylinder to obtain the radius of the cylindrical projection surface of the vessel. In the calculation of the top surface of the vessel cylinder in combination with the embodiment shown in fig. 6, the equation of the top surface of the vessel cylinder can be obtained by using the homeowner T1 and the vector V (normal vector), where the equation of the top surface of the vessel cylinder is expressed as: a (X-X0) +b (Y-Y0) +c (z-z 0) =0, wherein the foot T1 (X0, Y0, z 0) and one normal vector v= (a, B, C) on the top surface.

By the foot drop T2 and the vector V, the point French plane equation required for calculating the bottom surface of the vessel cylinder can be obtained. When calculating the bottom surface of the blood vessel cylinder, through the perpendicular foot T2 and the vector V (normal vector), a point French plane equation required by calculating the bottom surface of the blood vessel cylinder can be obtained, and the equation of the bottom surface of the blood vessel cylinder is expressed as: a (X-X2) +b (Y-Y2) +c (z-z 2) =0, wherein the foot T2 (X2, Y2, z 2) and a normal vector v= (a, B, C) on the bottom surface.

Dmax is the outer diameter of the vessel cylinder, dmin is the inner diameter of the vessel cylinder. The straight line L is the center line of the cylinder. At this time, the points on the center line are all within the cylinder. Cylindrical projection surface radius r= (dmax+dmin)/(2) of blood vessel. Therefore, the vascular distortion caused by stretching can be reduced as much as possible, and the radius of the cylindrical projection surface of the blood vessel is more accurate.

Step 305: an intersection point of the measured ray with the projection surface radius is determined.

The measuring rays are rays emitted to the wall of the blood vessel at any point in the central line of the blood vessel cylinder, and are used for generating intersection points with the radius of the projection surface.

Referring to fig. 8, fig. 8 is a schematic diagram of an intersection point of a measured ray and a radius of a projection surface in an embodiment of the present invention, where determining the intersection point of the measured ray and the radius of the projection surface may be implemented by:

Determining an included angle of the measurement rays according to the display requirement of the target blood vessel; in the top surface of the vessel cylinder, taking the central line of the vessel cylinder as the center, and determining a measured ray set according to the included angle of the measured rays; and calculating the intersection point of each measuring ray in the measuring ray set and the radius of the projection surface according to the scattering direction of each measuring ray in the measuring ray set. The value of the included angle of the measuring rays can be flexibly adjusted according to different types of target blood vessels, for example, the display resolutions of the coronary artery and the carotid artery are different, and the value of theta of the included angle is different; the resolution of the display for displaying the vessel cylindrical projection image can be 360 pixels, and the resolution of the display for displaying the vessel cylindrical projection image can be 3600 pixels when the theta value of the included angle is 1 degree. Wherein the preferred value of angle θ is 1 °. As shown in fig. 8, 360 rays can be generated on the top surface of the vessel cylinder with the vessel cylinder center line as the center and the angle θ as 1 °. The intersection point of each ray with the radius R may be noted as S01, S02, S03.

Step 306: and calculating the voxel value of the intersection point according to the coordinates of the intersection point.

Because an accurate vessel cylinder projection image needs to be formed, the vessel cylinder projection image provided by the application determines that the vessel cylinder is layered, then the voxel value of the intersection point in each layer of vessel cylinder is calculated, and the outer contour of the vessel cylinder projection can be accurately calculated by utilizing the voxel values of the intersection points in all layers of vessel cylinders.

In some embodiments of the present invention, calculating voxel values of the intersection points from coordinates of the intersection points may be accomplished by:

determining coordinates of an intersection point of each measuring ray in the measuring ray set and the radius of the projection surface; determining a minimum pixel pitch of the medical image data; according to the coordinates of the intersection point, the minimum pixel distance and the scattering direction of each measured ray, calculating a voxel value corresponding to each central point between the maximum distance value and the minimum distance value; and selecting the maximum voxel value from the voxel values corresponding to each central point as the voxel value of the intersection point. In combination with the embodiment shown in fig. 8, the voxel value can be calculated by using the three-line interpolation method from the coordinates of S01 in the medical image data. And calculating all voxel values in the outer diameter and inner diameter of the blood vessel cylinder along the radial direction inwards and outwards respectively by using the minimum Spacing (pixel Spacing) of the medical image data, and taking the maximum value (MIP) of the voxel values as the voxel value of the point S01. And traversing the intersection point of each ray and the radius R, and sequentially calculating voxel values of the intersection points S02, S03..S 360 points, thereby finally forming a voxel value record table shown in table 1.

TABLE 1

Step 307: and determining a cylindrical projection image of the blood vessel according to the voxel value of the intersection point.

Referring to fig. 9, fig. 9 is a schematic diagram of determining a cylindrical projection image of a blood vessel according to voxel values of intersection points in an embodiment of the present invention, first determining a pixel pitch from a top surface of the blood vessel cylinder to a bottom surface of the blood vessel cylinder; dividing the vessel cylinder according to the pixel spacing to obtain vessel cylinders of different levels; the central line of the vessel cylinder is taken as the center in the vessel cylinder of each level, and a measured ray set is determined according to the included angle of the measured rays; and calculating the intersection point of each measured ray in the vessel cylinder of each level and the radius of the projection surface according to the scattering direction of each measured ray in the measured ray set. For each level of vessel cylinder, determining coordinates of an intersection point of each measured ray and the radius of the projection surface in each level of vessel cylinder; calculating a voxel value corresponding to each central point between a maximum distance value and a minimum distance value in the vessel cylinder of each level according to the coordinates of the intersection point, the minimum pixel distance and the scattering direction of each measured ray in the vessel cylinder of each level; and selecting the maximum voxel value from the voxel values corresponding to each central point as the voxel value of the intersection point in the vessel cylinder of each level. In performing step 307, the vessel cylinder may be segmented into several levels from top to bottom, and voxel values of intersections of each level may be computed in turn. Then, along the cylindrical center line of the blood vessel, each level is calculated stepwise from the top surface to the bottom surface, and then the ray and intersection points S11, S12, S13..s1n are calculated. Finally, by performing steps 304-305 in a loop, the voxel values at points S12, S13. And so on until the bottom surface is calculated, the voxel values of Sn1, sn2.. Snn points can be calculated, and finally the voxel value record of the intersection point in the vessel cylinder of each level shown in table 2 is formed.

TABLE 2

S01	S02	S03	....	S0n
					S11	S12	S13	S1n
S21	S22	S23		S2n
					S31	S32	S33	Smn

In some embodiments of the present invention, since the medical image data DICOM is widely used in radiology, cardiovascular imaging and radiodiagnosis and diagnosis apparatuses, such as X-ray apparatuses, CT apparatuses, nuclear magnetic resonance apparatuses, and ultrasound apparatuses, for example, when determining cylindrical projections of a complex target vessel, the attenuation coefficient value corresponding to each voxel may be determined by multiple scans of the CT apparatus in different directions, so as to obtain a two-dimensional distribution of the attenuation coefficient values (which may also be understood as an attenuation coefficient matrix); then, each number in the attenuation coefficient matrix is converted into pixels (pixels) of different gray scales from black to white through a digital/analog converter (digital/analog converter), and the pixels are arranged in a matrix to form a CT image of the target blood vessel shown in fig. 9.

In order to better illustrate the cylindrical projection image determination method of a blood vessel provided in the present application, the working procedure of the cylindrical projection image determination method of a blood vessel provided in the present application is described below with the blood vessel projection image determination procedure in the coronary artery diagnosis field as an example, and in the coronary artery study, it is shown that functional stenosis estimated by fractional flow reserve (Fractional Flow Reserve, FFR) is superior to anatomical stenosis at risk of ischemia. The accuracy of the cut-off value of 0.8 exceeds 90% in determining whether the stenosis is functionally ischemic. Compared with percutaneous coronary intervention under coronary angiography guidance, percutaneous coronary intervention under fractional flow reserve guidance can reduce mortality, myocardial infarction rate and repeated revascularization rate. The coronary artery blood flow reserve fraction is widely used as a clinical index for determining stent insertion in coronary artery diseases, but the accurate blood flow reserve fraction needs to be firstly determined by the vessel cylindrical projection of the coronary artery to perform simulation calculation of the blood flow velocity in the vessel, but the vessel of the coronary artery is curved in the body, and no matter what projection mode is used, larger deformation can be caused, so that the method has no practical application significance. With the development of computer technology, the application of using DSA (Digital Subtraction Angiography, digital silhouette angiography) equipment to assist in vascular research is becoming wider, for example, a three-dimensional vascular model for simulating the morphology of a blood vessel can be constructed according to the blood vessel image output by the DSA equipment. In the related art, the process of constructing a three-dimensional blood vessel model from a blood vessel image includes: two-dimensional blood vessel center lines in the two blood vessel images are obtained, a three-dimensional blood vessel center line is directly obtained based on the two-dimensional blood vessel center lines, and then a three-dimensional blood vessel model is built based on the three-dimensional blood vessel center line. Because the DSA equipment can generate unavoidable mechanical errors in the operation process, the reliability of the two-dimensional blood vessel center line in the blood vessel image is poor, and a large deviation can exist between the three-dimensional blood vessel center line obtained directly based on the two-dimensional blood vessel center lines and the real blood vessel center line, so that the accuracy of the constructed three-dimensional blood vessel model is poor, and a doctor is not facilitated to obtain the cylindrical projection image of the blood vessel accurately.

However, by the cylindrical projection image determining method of the blood vessel, deformation can be reduced to the greatest extent, and a doctor can know lesion information of the blood vessel of a patient in an integral manner conveniently.

Fig. 10 is a schematic diagram of a process for determining a cylindrical projection image of a blood vessel according to an embodiment of the present invention, which specifically includes the following steps:

step 1001: a set of coronary vessel centerline points and CT images are acquired by a medical device.

Step 1002: a first center point T1 and a second center point T2 are calculated which are farthest from the center line point set of the coronary artery blood vessel.

Step 1003: and calculating the top surface equation, the bottom surface equation, the inner diameter and the outer diameter of the coronary artery vessel cylinder according to the first central point T1 and the second central point T2.

Step 1004: and calculating the projection surface radius of the coronary artery blood vessel according to the sum of the inner diameter and the outer diameter.

Step 1005: and determining the intersection point of the measured ray and the radius of the projection surface according to the resolution required by the coronary artery display.

Step 1006: and calculating the maximum voxel value of the intersection point according to the coordinates of the intersection point.

Step 1007: and calculating all intersection points of the measured rays and the projection surface radius in the coronary artery according to the top surface equation and the bottom surface equation of the coronary artery vessel cylinder.

Step 1008: and determining a cylindrical projection image of the blood vessel of the coronary artery according to the voxel values of all the intersection points.

Fig. 11 is a schematic view of a cylindrical projection image of a coronary artery in an embodiment of the present invention, where when the resolution of the schematic view of the coronary artery shown in fig. 11 needs to be adjusted, the value of the included angle of the measurement ray is adjusted to meet the resolution requirement of the schematic view of the coronary artery.

The beneficial technical effects are as follows:

the invention obtains a blood vessel central line point set and medical image data of a target blood vessel; calculating a first center point and a second center point which are farthest from the center line point of the blood vessel; calculating the volume parameters of the vessel cylinder corresponding to the target vessel according to the first center point and the second center point; calculating the radius of a cylindrical projection surface of the blood vessel according to the volume parameter; determining an intersection point of the measured ray and the radius of the projection surface; calculating voxel values of the intersection points according to the coordinates of the intersection points; and determining a cylindrical projection image of the blood vessel according to the voxel value of the intersection point. Therefore, the cylindrical projection image of the target blood vessel can be calculated by automatically utilizing the blood vessel center line point set and the medical image data of the target blood vessel, the deformation of the target blood vessel can be reduced to the greatest extent, a doctor can conveniently and accurately grasp the lesion information of the target blood vessel by utilizing the cylindrical projection image of the blood vessel, and the doctor is assisted in processing the target blood vessel.

The above embodiments are merely examples of the present invention, and are not intended to limit the scope of the present invention, so any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention should be included in the scope of the present invention.

Claims

1. A method for determining a cylindrical projection image of a blood vessel, the method comprising:

2. The method of claim 1, wherein the calculating a first center point and a second center point in the set of vessel centerline points comprises:

calculating a distance between each of the center points in the set of vessel centerline points;

And screening the two center points with the farthest distances as the first center point and the second center point.

3. The method of claim 1, wherein said calculating a volumetric parameter of the vessel cylinder from the first center point and the second center point comprises:

calculating the central line of the vessel cylinder and a central line vector corresponding to the central line according to the first central point and the second central point;

determining a distance set and a drop foot set of each center point in the blood vessel center line point set to the center line of the blood vessel cylinder;

calculating a maximum distance value and a minimum distance value in the distance set;

and calculating the distance between adjacent drop feet in the drop foot set, and determining a first drop foot and a second drop foot with the largest distance.

4. A method according to claim 3, wherein said calculating a cylindrical projection surface radius of said vessel from said volume parameter comprises:

determining a top surface of the vessel cylinder from the first foot drop and the centerline vector;

determining the bottom surface of the vessel cylinder according to the second foot drop and the central line vector;

determining the outer diameter of the vessel cylinder according to the maximum distance value;

Determining the inner diameter of the vessel cylinder according to the minimum distance value;

and calculating the radius of the cylindrical projection surface of the blood vessel according to the outer diameter of the blood vessel cylinder and the inner diameter of the blood vessel cylinder.

5. The method of claim 4, wherein determining the intersection of the measurement ray with the projection surface radius comprises:

determining an included angle of the measurement rays according to the display requirement of the target blood vessel;

in the top surface of the vessel cylinder, taking the central line of the vessel cylinder as the center, and determining a measured ray set according to the included angle of the measured rays;

and calculating the intersection point of each measuring ray in the measuring ray set and the radius of the projection surface according to the scattering direction of each measuring ray in the measuring ray set.

6. The method of claim 5, wherein calculating the voxel value of the intersection point from the coordinates of the intersection point comprises:

determining coordinates of an intersection point of each measuring ray in the measuring ray set and the radius of the projection surface;

determining a minimum pixel pitch of the medical image data;

And selecting the maximum voxel value from the voxel values corresponding to each central point as the voxel value of the intersection point.

7. The method of claim 6, wherein the method further comprises:

determining a pixel pitch from a top surface of the vessel cylinder to a bottom surface of the vessel cylinder;

dividing the vessel cylinder according to the pixel spacing to obtain vessel cylinders of different levels;

a blood vessel cylinder of each level is centered on the central line of the blood vessel cylinder, and a measured ray set is determined according to the included angle of the measured rays;

and calculating the intersection point of each measured ray in the vessel cylinder of each level and the radius of the projection surface according to the scattering direction of each measured ray in the measured ray set.

8. The method of claim 7, wherein the method further comprises:

determining coordinates of an intersection point of each measuring ray and the radius of the projection surface in the vessel cylinder of each level;

calculating a voxel value corresponding to each central point between the maximum distance value and the minimum distance value in the vessel cylinder of each level according to the coordinates of the intersection point, the minimum pixel distance and the scattering direction of each measured ray;

And screening the maximum voxel value from the voxel values corresponding to each central point as the voxel value of the intersection point in the vessel cylinder of each level.

9. A cylindrical projection image determination apparatus for a blood vessel, the apparatus comprising:

10. A computer readable storage medium storing executable instructions which when executed by a processor implement the cylindrical projection image determination method of a blood vessel according to any one of claims 1-8.