Method and system for classifying aneurysm in a blood vessel

Abstract

There are provided methods, systems and non-transitory storage mediums for classifying aneurysms in a blood vessel of a given patient. Medically acquired images representing a blood vessel over a portion of the cardiac cycle are received. The images are segmented to obtain segmented anatomical structures of the wall and the lumen of the blood vessel. The volumetric changes of the outer wall and the lumen are calculated over the portion of the cardiac cycle. The volumetric changes of the thrombus are calculated based on the volumetric changes of the outer wall and the lumen. The aneurysm is classified as one four types based at least on the volumetric changes of the lumen and the thrombus. This classification may be used to assess the severity of the aneurysm.

Description

METHOD AND SYSTEM FOR CLASSIFYING ANEURYSM IN A BLOODVESSELCROSS-REFERENCE

[0001] The present application claims priority on U.S. Provisional Patent Application No. 63 / 673,874, filed on July 22, 2024, the content of which is incorporated herein by reference.FIELD

[0002] The present technology pertains to the field of medical imaging. More precisely, the present technology relates to methods, systems and non-transitory computer readable mediums for classifying aneurysms based on volume changes in a lumen and wall of a blood vessel which may be indicative of a thrombus response to a blood pressure load.BACKGROUND

[0003] An abdominal aortic aneurysm (AAA) is defined as a focal dilation of the aorta. Identification of AAA is standard by confirming the dilated geometry with medical imaging, however, the prognosis of AAA after the identification is not well established. The major complication of AAA is the risk of sudden rupture, which is associated with a high (70%) mortality rate before any emergency surgery is performed. The only classifier for the risk of AAA rupture is the size of the vessel (Kessler et al., 2022). AAAs with diameters exceeding 5-5.4 cm are considered at risk of rupture within a year (Lederle et al. 2002, Bown et al., 2013), and higher diameters increase the temporal proximity of the rupture. The annual estimation of a 5% unexpected rupture risk for AAAs with a diameter of less than 5 cm indicates the contribution of other factors to the risk of AAA rupture.

[0004] Because of the severity of the consequences of AAA rupture, enormous effort focused on developing better indicators helping to identify the risk. The indicators arebased on medical imaging routinely acquired during the surveillance of AAAs, namely static three-dimensional (3D) images. High AAAs’ growth rate, disrupted calcification, signs of thrombus fissures are signs of risk of AAA rupture (Kessler et al. 2022). More advanced indicators are based on geometrical or flow dynamics patterns obtained directly from imaging or through computational fluid dynamics simulation. The most used indicator of altered blood flow that has been correlated to rupture sites in the literature is time-averaged wall shear stress resulting from the forces of blood flow on the lumen. Low wall shear stress predominates at sites of abdominal aortic aneurysm rupture (Boyd et al., 2016). Efforts were also dedicated to identifying strain on the AAA wall (Forneris et al., 2020, Derwich et al., 2023), and to compute stress-based parameters of risk (Riveros et al., 2015, Siika et al., 2018, Throop et al., 2022, Siika et al., 2023). Statistics and machine learning tools were used to combine indicators into predictors (Rengarajan et al., 2020, Forneris et al., 2023, Siika et al., 2023, Vermeulen et al., 2023, Wang et al., 2023). All these efforts led to recognizing the complexity of AAAs prognosis but not necessarily to better understanding of the key factors leading to AAA rupture.SUMMARY

[0005] It is an object of the present technology to ameliorate at least some of the inconveniences present in the prior art. One or more implementations of the present technology may provide and / or broaden the scope of approaches to and / or methods of achieving the aims and objects of the present technology.

[0006] One or more implementations of the present technology have been developed based on developers’ appreciation that one of the main reasons for the lack of adoption of stress and computational fluid dynamics methods into the clinical practice is the complexity of the computational models that requires prohibitive computational time / cost (several hours, see for example Gasser et al., 2023), and the lack of an intuitive and effective classification of the results that could lead to improved clinical prognosis.

[0007] Developers of the present technology propose a solution that uses multi-phase (dynamic 4D) images often acquired during a patient’s screening. One or moreimplementations of the present technology classify aneurysms such as AAAs into four categories or types according to volumetric changes in the lumen, outer wall and thrombus which are indicative of their response to the pressure load from the circulating blood that is extracted from dynamic image analysis.

[0008] In accordance with a broad aspect of the present technology, there is provided a method for classifying an aneurysm in a blood vessel of a given patient having been diagnosed with the aneurysm, the method being executed by at least one processor, the method comprising: receiving a set of images representing the blood vessel of the given patient over at least a portion of a cardiac cycle, the set of images having been acquired by a medical imaging apparatus, the blood vessel comprising the aneurysm; segmenting the set of images to obtain at least a segmented outer wall of the aneurysm and a segmented lumen at a plurality of time steps over at least the portion of the cardiac cycle; calculating, based on the segmented outer wall and the segmented lumen over the plurality of time steps, wall volumetric changes and lumen volumetric changes; calculating, based on the lumen volumetric changes and the outer wall volumetric changes, thrombus volumetric changes over the plurality of time steps; classifying, based on at least the lumen volumetric changes and the thrombus volumetric changes, the aneurysm as one of: a first type of aneurysm, a second type of aneurysm, a third type of aneurysm and a fourth type of aneurysm.

[0009] In one or more implementations of the method, the step of classifying is further based on the outer wall volumetric changes, the aneurysm being classified as one of: the first type of aneurysm in response to the lumen volumetric changes being negative over a majority of the plurality of time steps, the second type of aneurysm in response to: the lumen volumetric changes being within a first threshold range, and the outer wall volumetric changes and the thrombus volumetric changes being within a second threshold range, the third type of aneurysm in response to: the lumen volumetric changes and the thrombus volumetric changes being within a third threshold range; and the fourth type of aneurysm in response to: the lumen volumetric changes being within a fourth threshold range of the outer wall volumetric changes, and the thrombus volumetric changes being negative for at least one of the plurality of time steps.

[0010] In one or more implementations of the method, the method further comprises the step of calculating an average thrombus volumetric change based on the thrombus volumetric changes and an average lumen volumetric change based on the lumen volumetric changes, the step of classifying comprising classifying, based on the average thrombus volumetric change and the average lumen volumetric change, the aneurysm as one of: the first type of aneurysm when the average thrombus volumetric change is at least equal to the average lumen volumetric change and the average lumen volumetric change is less than a first change threshold; the second type of aneurysm when the average thrombus volumetric change is at least equal to the average lumen volumetric change and the average lumen volumetric change is at least equal to the first change threshold; the third type of aneurysm when the average thrombus volumetric change is less than the average lumen volumetric change and the average thrombus volumetric change is at least equal to a second change threshold; and the fourth type of aneurysm when the average thrombus volumetric change is less than the average lumen volumetric change and the average thrombus volumetric change is less than the second change threshold.[OOH] In one or more implementations of the method, an initial thrombus volumetric change and an initial lumen volumetric change are each associated with a first one of the plurality of time steps, the method further comprising: dividing the average thrombus volumetric change by the initial thrombus volumetric change, thereby obtaining a thrombus volumetric change percentage; and dividing the average lumen volumetric change by the initial lumen volumetric change, thereby obtaining a lumen volumetric change percentage, the step of classifying comprising classifying, based on the thrombus volumetric change percentage and the lumen volumetric change percentage, the aneurysm as one of: the first type of aneurysm when the thrombus volumetric change percentage is at least equal to the lumen volumetric change percentage and the lumen volumetric change percentage is less than a first percentage threshold; the second type of aneurysm when the thrombus volumetric change percentage is at least equal to the lumen volumetric change percentage and the lumen volumetric change percentage is at least equal to the first percentage threshold; the third type of aneurysm when the thrombus volumetric change percentage is less than the lumen volumetric change percentage and the thrombus volumetric change percentage is at least equal to a second percentage threshold; and the fourth type ofaneurysm when the thrombus volumetric change percentage is less than the lumen volumetric change percentage and the thrombus volumetric change percentage is less than the second percentage threshold.

[0012] In one or more implementations of the method, the first type of aneurysm is indicative of wall delamination.

[0013] In one or more implementations of the method, the fourth type of aneurysm is indicative of an impending rupture of the aneurysm.

[0014] In one or more implementations of the method, said calculating, based on the lumen volumetric changes and the outer wall volumetric changes, the thrombus volumetric changes over the plurality of time steps comprises: calculating a difference between the outer wall volumetric changes and the lumen volumetric changes.

[0015] In one or more implementations of the method, the at least the first portion comprises a majority of the plurality of time steps.

[0016] In one or more implementations of the method, said calculating, based on the segmented outer wall and the segmented lumen over the plurality of time steps, the wall volumetric changes and the lumen volumetric changes comprises: generating, based on the segmented outer wall over the plurality of time steps, outer wall meshes over the plurality of time steps, calculating volumes of the outer wall meshes over the plurality of time steps, determining the wall volumetric changes based on the volumes of the outer wall meshes over the plurality of time steps, generating, based on the segmented lumen over the plurality of time steps, segmented lumen meshes over the plurality of time steps, calculating volumes of the outer wall meshes over the plurality of time steps, and determining the lumen volumetric changes based on the volumes of the lumen meshes over the plurality of time steps.

[0017] In one or more implementations of the method, said determining the lumen volumetric changes based on the volumes of the lumen meshes over the plurality of time steps and determining the wall volumetric changes based on the volumes of the outer wall meshes over the plurality of time steps comprises determining the lumen volumetricchanges based on the volumes of the lumen meshes over the plurality of time steps and determining the wall volumetric changes based on the volumes of the outer wall meshes over ten evenly spaced time steps of the cardiac cycle.

[0018] In one or more implementations of the method, said determining the lumen volumetric changes based on the volumes of the lumen meshes over the plurality of time steps and determining the wall volumetric changes based on the volumes of the outer wall meshes over the plurality of time steps are relative to a diastolic time of the cardiac cycle.

[0019] In accordance with another broad aspect of the present technology, there is provided a system for classifying an aneurysm in a blood vessel of a given patient having been diagnosed with the aneurysm, the system comprising: a processor, a non-transitory storage medium operatively connected to the at least one processor, the non-transitory storage medium storing computer-readable instructions thereon, the at least one processor, upon executing the computer-readable instructions, being configured for: receiving a set of images representing the blood vessel of the given patient over at least a portion of a cardiac cycle, the set of images having been acquired by a medical imaging apparatus, the blood vessel comprising the aneurysm; segmenting the set of images to obtain at least a segmented outer wall of the aneurysm and a segmented lumen at a plurality of time steps over at least the portion of the cardiac cycle; calculating, based on the segmented outer wall and the segmented lumen over the plurality of time steps, wall volumetric changes and lumen volumetric changes; calculating, based on the lumen volumetric changes and the outer wall volumetric changes, thrombus volumetric changes over the plurality of time steps; classifying, based on at least the lumen volumetric changes and the thrombus volumetric changes, the aneurysm as one of: a first type of aneurysm, a second type of aneurysm, a third type of aneurysm and a fourth type of aneurysm.

[0020] In one or more implementations of the system, the step of classifying is further based on the outer wall volumetric changes, the at least one processor being configured for classifying the aneurysm as one of: the first type of aneurysm in response to the lumen volumetric changes being negative over a majority of the plurality of time steps, the second type of aneurysm in response to: the lumen volumetric changes being within a firstthreshold range, and the outer wall volumetric changes and the thrombus volumetric changes being within a second threshold range, the third type of aneurysm in response to: the lumen volumetric changes and the thrombus volumetric changes being within a third threshold range; and the fourth type of aneurysm in response to: the lumen volumetric changes being within a fourth threshold range of the outer wall volumetric changes, and the thrombus volumetric changes being negative for at least one of the plurality of time steps.

[0021] In one or more implementations of the system, the at least one processor is further configured for calculating an average thrombus volumetric change based on the thrombus volumetric changes and an average lumen volumetric change based on the lumen volumetric changes, the at least one processor being configured for classifying, based on the average thrombus volumetric change and the average lumen volumetric change, the aneurysm as one of: the first type of aneurysm when the average thrombus volumetric change is at least equal to the average lumen volumetric change and the average lumen volumetric change is less than a first change threshold; the second type of aneurysm when the average thrombus volumetric change is at least equal to the average lumen volumetric change and the average lumen volumetric change is at least equal to the first change threshold; the third type of aneurysm when the average thrombus volumetric change is less than the average lumen volumetric change and the average thrombus volumetric change is at least equal to a second change threshold; and the fourth type of aneurysm when the average thrombus volumetric change is less than the average lumen volumetric change and the average thrombus volumetric change is less than the second change threshold.

[0022] In one or more implementations of the method, an initial thrombus volumetric change and an initial lumen volumetric change are each associated with a first one of the plurality of time steps, the at least one processor being further configured for: dividing the average thrombus volumetric change by the initial thrombus volumetric change, thereby obtaining a thrombus volumetric change percentage; and dividing the average lumen volumetric change by the initial lumen volumetric change, thereby obtaining a lumen volumetric change percentage, the at least one processor being configured for classifying, based on the thrombus volumetric change percentage and the lumen volumetric changepercentage, the aneurysm as one of: the first type of aneurysm when the thrombus volumetric change percentage is at least equal to the lumen volumetric change percentage and the lumen volumetric change percentage is less than a first percentage threshold; the second type of aneurysm when the thrombus volumetric change percentage is at least equal to the lumen volumetric change percentage and the lumen volumetric change percentage is at least equal to the first percentage threshold; the third type of aneurysm when the thrombus volumetric change percentage is less than the lumen volumetric change percentage and the thrombus volumetric change percentage is at least equal to a second percentage threshold; and the fourth type of aneurysm when the thrombus volumetric change percentage is less than the lumen volumetric change percentage and the thrombus volumetric change percentage is less than the second percentage threshold

[0023] In one or more implementations of the system, the first type of aneurysm is indicative of wall delamination.

[0024] In one or more implementations of the system, the fourth type of aneurysm is indicative of an impending rupture of the aneurysm.

[0025] In one or more implementations of the system, said calculating, based on the lumen volumetric changes and the outer wall volumetric changes, the thrombus volumetric changes over the plurality of time steps comprises: calculating a difference between the outer wall volumetric changes and the lumen volumetric changes.

[0026] In one or more implementations of the system, the at least the first portion comprises a majority of the plurality of time steps.

[0027] In one or more implementations of the system, said calculating, based on the segmented outer wall and the segmented lumen over the plurality of time steps, the wall volumetric changes and the lumen volumetric changes comprises: generating, based on the segmented outer wall over the plurality of time steps, outer wall meshes over the plurality of time steps, calculating volumes of the outer wall meshes over the plurality of time steps, determining the wall volumetric changes based on the volumes of the outer wall meshes over the plurality of time steps, generating, based on the segmented lumen over the pluralityof time steps, segmented lumen meshes over the plurality of time steps, calculating volumes of the outer wall meshes over the plurality of time steps, and determining the lumen volumetric changes based on the volumes of the lumen meshes over the plurality of time steps.

[0028] In one or more implementations of the system, said determining the lumen volumetric changes based on the volumes of the lumen meshes over the plurality of time steps and determining the wall volumetric changes based on the volumes of the outer wall meshes over the plurality of time steps comprises determining the lumen volumetric changes based on the volumes of the lumen meshes over the plurality of time steps and determining the wall volumetric changes based on the volumes of the outer wall meshes over ten evenly spaced time steps of the cardiac cycle.

[0029] In one or more implementations of the system, said determining the lumen volumetric changes based on the volumes of the lumen meshes over the plurality of time steps and determining the wall volumetric changes based on the volumes of the outer wall meshes over the plurality of time steps are relative to a diastolic time of the cardiac cycle.

[0030] In accordance with a broad aspect of the present technology, there is provided a non-transitory storage medium storing computer-readable instructions thereon, the computer-readable instructions upon being executed by at least one processor, cause the at least one processor to perform the above-described method.

[0031] Terms and Definitions

[0032] In the context of the present specification, a “server” is a computer program that is running on appropriate hardware and is capable of receiving requests (e.g., from electronic devices) over a network (e.g., a communication network), and carrying out those requests, or causing those requests to be carried out. The hardware may be one physical computer or one physical computer system, but neither is required to be the case with respect to the present technology. In the present context, the use of the expression “a server” is not intended to mean that every task (e.g., received instructions or requests) or any particular task will have been received, carried out, or caused to be carried out, by the sameserver (i.e., the same software and / or hardware); it is intended to mean that any number of software elements or hardware devices may be involved in receiving / sending, carrying out or causing to be carried out any task or request, or the consequences of any task or request; and all of this software and hardware may be one server or multiple servers, both of which are included within the expressions “at least one server” and “a server”.[00331 In the context of the present specification, “electronic device” is any computing apparatus or computer hardware that is capable of running software appropriate to the relevant task at hand. Thus, some (non-limiting) examples of electronic devices include general purpose personal computers (desktops, laptops, netbooks, etc.), mobile computing devices, smartphones, and tablets, and network equipment such as routers, switches, and gateways. It should be noted that an electronic device in the present context is not precluded from acting as a server to other electronic devices. The use of the expression “an electronic device” does not preclude multiple electronic devices being used in receiving / sending, carrying out or causing to be carried out any task or request, or the consequences of any task or request, or steps of any method described herein. In the context of the present specification, a “client device” refers to any of a range of end-user client electronic devices, associated with a user, such as personal computers, tablets, smartphones, and the like.

[0034] In the context of the present specification, unless expressly provided otherwise, a computer system may refer, but is not limited to, an “electronic device”, a “client device”, a “computing device”, an “operation system”, a “system”, a “computer-based system”, a “computer system”, a “network system”, a “network device”, a “controller unit”, a “monitoring device”, a “control device”, a “server”, and / or any combination thereof appropriate to the relevant task at hand.

[0035] In the context of the present specification, the expression "computer readable storage medium" (also referred to as "storage medium” and “storage”) is intended to include non-transitory media of any nature and kind whatsoever, including without limitation RAM, ROM, disks (CD-ROMs, DVDs, floppy disks, hard drivers, etc.), USB keys, solid state-drives, tape drives, etc. A plurality of components may be combined toform the computer information storage media, including two or more media components of a same type and / or two or more media components of different types.

[0036] In the context of the present specification, a "database" is any structured collection of data, irrespective of its particular structure, the database management software, or the computer hardware on which the data is stored, implemented or otherwise rendered available for use. A database may reside on the same hardware as the process that stores or makes use of the information stored in the database or it may reside on separate hardware, such as a dedicated server or plurality of servers.

[0037] In the context of the present specification, the expression “information” includes information of any nature or kind whatsoever capable of being stored in a database. Thus, information includes, but is not limited to audiovisual works (images, movies, sound records, presentations etc.), data (location data, numerical data, etc.), text (opinions, comments, questions, messages, etc.), documents, spreadsheets, lists of words, etc.

[0038] In the context of the present specification, unless expressly provided otherwise, an “indication” of an information element may be the information element itself or a pointer, reference, link, or other indirect mechanism enabling the recipient of the indication to locate a network, memory, database, or other computer-readable medium location from which the information element may be retrieved. For example, an indication of a document could include the document itself (i.e., its contents), or it could be a unique document descriptor identifying a file with respect to a particular file system, or some other means of directing the recipient of the indication to a network location, memory address, database table, or other location where the file may be accessed. As one skilled in the art would recognize, the degree of precision required in such an indication depends on the extent of any prior understanding about the interpretation to be given to information being exchanged as between the sender and the recipient of the indication. For example, if it is understood prior to a communication between a sender and a recipient that an indication of an information element will take the form of a database key for an entry in a particular table of a predetermined database containing the information element, then the sending of the database key is all that is required to effectively convey the information element to therecipient, even though the information element itself was not transmitted as between the sender and the recipient of the indication.

[0039] In the context of the present specification, the expression “communication network” is intended to include a telecommunications network such as a computer network, the Internet, a telephone network, a Telex network, a TCP / IP data network (e.g., a WAN network, a LAN network, etc.), and the like. The term “communication network” includes a wired network or direct-wired connection, and wireless media such as acoustic, radio frequency (RF), infrared and other wireless media, as well as combinations of any of the above.

[0040] In the context of the present specification, the words “first”, “second”, “third”, etc. have been used as adjectives only for the purpose of allowing for distinction between the nouns that they modify from one another, and not for the purpose of describing any particular relationship between those nouns. Thus, for example, it should be understood that, the use of the terms “first server” and “third server” is not intended to imply any particular order, type, chronology, hierarchy or ranking (for example) of / between the servers, nor is their use (by itself) intended to imply that any “second server” must necessarily exist in any given situation. Further, as is discussed herein in other contexts, reference to a “first” element and a “second” element does not preclude the two elements from being the same actual real-world element. Thus, for example, in some instances, a “first” server and a “second” server may be the same software and / or hardware, in other cases they may be different software and / or hardware.

[0041] Implementations of the present technology each have at least one of the above- mentioned objects and / or aspects, but do not necessarily have all of them. It should be understood that some aspects of the present technology that have resulted from attempting to attain the above-mentioned object may not satisfy this object and / or may satisfy other objects not specifically recited herein.

[0042] Additional and / or alternative features, aspects and advantages of implementations of the present technology will become apparent from the following description, the accompanying drawings and the appended claims.BRIEF DESCRIPTION OF THE DRAWINGS

[0043] For a beter understanding of the present technology, as well as other aspects and further features thereof, reference is made to the following description which is to be used in conjunction with the accompanying drawings, where:

[0044] FIG. 1 illustrates a schematic diagram of a computing device in accordance with one or more non-limiting implementations of the present technology.

[0045] FIG. 2 illustrates a schematic diagram of a communication system in accordance with one or more non-limiting implementations of the present technology.

[0046] FIG. 3 illustrates a schematic diagram of volume comparison and classification procedure 300 in accordance with one or more non-limiting implementations of the present technology.

[0047] FIG. 4 illustrates graphs plotting volumetric changes of a lumen, volumetric changes of a wall, and volumetric changes of a thrombus across a cardiac cycle for each of the four aneurysm types in accordance with one or more non-limiting implementations of the present technology.

[0048] FIG. 5 illustrates graphs plotting volumetric changes of a lumen, volumetric changes of a wall, and volumetric changes of a thrombus across a cardiac cycle for 2 patients exhibiting an aneurysm of type I in accordance with one or more non-limiting implementations of the present technology.

[0049] FIG. 6 illustrates graphs plotting volumetric changes of a lumen, volumetric changes of a wall, and volumetric changes of a thrombus across a cardiac cycle for 5 patients exhibiting an aneurysm of type II in accordance with one or more non-limiting implementations of the present technology.

[0050] FIG. 7 illustrates graphs plotting volumetric changes of a lumen, volumetric changes of a wall, and volumetric changes of a thrombus across a cardiac cycle for 3 patients exhibiting an aneurysm of type III in accordance with one or more non-limiting implementations of the present technology.

[0051] FIG. 8 illustrates graphs plotting volumetric changes of a lumen, volumetric changes of a wall, and volumetric changes of a thrombus across a cardiac cycle for 4 patients exhibiting an aneurysm of type IV in accordance with one or more non-limiting implementations of the present technology.

[0052] FIG. 9 illustrates a flowchart of a method of classifying an aneurysm, the method being executed in accordance with one or more non-limiting implementations of the present technology.DETAILED DESCRIPTION

[0053] The examples and conditional language recited herein are principally intended to aid the reader in understanding the principles of the present technology and not to limit its scope to such specifically recited examples and conditions. It will be appreciated that those skilled in the art may devise various arrangements which, although not explicitly described or shown herein, nonetheless embody the principles of the present technology and are included within its spirit and scope.

[0054] Furthermore, as an aid to understanding, the following description may describe relatively simplified implementations of the present technology. As persons skilled in the art would understand, various implementations of the present technology may be of a greater complexity.

[0055] In some cases, what are believed to be helpful examples of modifications to the present technology may also be set forth. This is done merely as an aid to understanding, and, again, not to define the scope or set forth the bounds of the present technology. These modifications are not an exhaustive list, and a person skilled in the art may make other modifications while nonetheless remaining within the scope of the present technology. Further, where no examples of modifications have been set forth, it should not be interpreted that no modifications are possible and / or that what is described is the sole manner of implementing that element of the present technology.

[0056] Moreover, all statements herein reciting principles, aspects, and implementations of the present technology, as well as specific examples thereof, are intended to encompass both structural and functional equivalents thereof, whether they are currently known or developed in the future. Thus, for example, it will be appreciated by those skilled in the art that any block diagrams herein represent conceptual views of illustrative circuitry embodying the principles of the present technology. Similarly, it will be appreciated that any flowcharts, flow diagrams, state transition diagrams, pseudo-code, and the like represent various processes which may be substantially represented in computer-readable media and so executed by a computer or processor, whether or not such computer or processor is explicitly shown.

[0057] The functions of the various elements shown in the figures, including any functional block labeled as a "processor" or a “graphics processing unit”, may be provided through the use of dedicated hardware as well as hardware capable of executing software in association with appropriate software. When provided by a processor, the functions may be provided by a single dedicated processor, by a single shared processor, or by a plurality of individual processors, some of which may be shared. In some non-limiting implementations of the present technology, the processor may be a general-purpose processor, such as a central processing unit (CPU) or a processor dedicated to a specific purpose, such as a graphics processing unit (GPU). Moreover, explicit use of the term "processor" or "controller" should not be construed to refer exclusively to hardware capable of executing software, and may implicitly include, without limitation, digital signal processor (DSP) hardware, network processor, application specific integrated circuit (ASIC), field programmable gate array (FPGA), read-only memory (ROM) for storing software, random access memory (RAM), and non-volatile storage. Other hardware, conventional and / or custom, may also be included.

[0058] Software modules, or simply modules which are implied to be software, may be represented herein as any combination of flowchart elements or other elements indicating performance of process steps and / or textual description. Such modules may be executed by hardware that is expressly or implicitly shown.

[0059] With these fundamentals in place, we will now consider some non-limiting implementations of the present technology.

[0060] With reference to FIG. 1, there is illustrated a schematic diagram of a computing device 100 suitable for use with some non-limiting implementations of the present technology.

[0061] Computing device

[0062] The computing device 100 comprises various hardware components including one or more single or multi-core processors collectively represented by processor 110, a graphics processing unit (GPU) 111, a solid-state drive 120, a random-access memory 130, a display interface 140, and an input / output interface 150.

[0063] Communication between the various components of the computing device 100 may be enabled by one or more internal and / or external buses 160 (e.g. a PCI bus, universal serial bus, IEEE 1394 “Firewire” bus, SCSI bus, Serial- ATA bus, etc.), to which the various hardware components are electronically coupled.

[0064] The input / output interface 150 may be coupled to a touchscreen 190 and / or to the one or more internal and / or external buses 160. The touchscreen 190 may be part of the display. In some implementations, the touchscreen 190 is the display. The touchscreen 190 may equally be referred to as a screen 190. In the implementations illustrated in FIG. 2, the touchscreen 190 comprises touch hardware 194 (e.g., pressure-sensitive cells embedded in a layer of a display allowing detection of a physical interaction between a user and the display) and a touch input / output controller 192 allowing communication with the display interface 140 and / or the one or more internal and / or external buses 160. In some implementations, the input / output interface 150 may be connected to a keyboard (not shown), a mouse (not shown) or a trackpad (not shown) allowing the user to interact with the computing device 100 in addition or in replacement of the touchscreen 190.

[0065] According to implementations of the present technology, the solid-state drive 120 stores program instructions suitable for being loaded into the random-access memory 130 and executed by the processor 110 and / or the GPU 111 for generating aparametric mesh. For example, the program instructions may be part of a library or an application.

[0066] The computing device 100 may be implemented in the form of a server, a desktop computer, a laptop computer, a tablet, a smartphone, a personal digital assistant or any device that may be configured to implement the present technology, as it may be understood by a person skilled in the art.

[0067] System

[0068] Referring to FIG. 2, there is shown a schematic diagram of a communication system 200, which will be referred to as the system 200, the system 200 being suitable for implementing non-limiting implementations of the present technology. It is to be expressly understood that the system 200 as illustrated is merely an illustrative implementation of the present technology. Thus, the description thereof that follows is intended to be only a description of illustrative examples of the present technology. This description is not intended to define the scope or set forth the bounds of the present technology. In some cases, what are believed to be helpful examples of modifications to the system 200 may also be set forth below. This is done merely as an aid to understanding, and, again, not to define the scope or set forth the bounds of the present technology. These modifications are not an exhaustive list, and, as a person skilled in the art would understand, other modifications are likely possible. Further, where this has not been done (i.e., where no examples of modifications have been set forth), it should not be interpreted that no modifications are possible and / or that what is described is the sole manner of implementing that element of the present technology. As a person skilled in the art would understand, this is likely not the case. In addition, it is to be understood that the system 200 may provide in certain instances simple implementations of the present technology, and that where such is the case they have been presented in this manner as an aid to understanding. As persons skilled in the art would understand, various implementations of the present technology may be of a greater complexity.

[0069] The system 200 comprises inter alia one or more medical imaging apparatuses 210, a server 230 and a database 235 coupled over a communications network 220 via respective communication links 225 (not separately numbered).

[0070] In one or more implementations, at least a portion of the system 200 implements the Picture Archiving and Communication System (PACS) technology.

[0071] The one or more medical imaging apparatuses 210 are operated by a user (e.g., physician or technician) to acquire medical images of the body of a given patient.

[0072] Medical Imaging Apparatus

[0073] The one or more medical imaging apparatuses 210 will now be referred to as the medical imaging apparatus 210.

[0074] The medical imaging apparatus 210 is configured to inter alia: (i) acquire, according to acquisition parameters, one or more images of anatomical structures of interest of a given patient; and (ii) transmit the images to the workstation computer 215 and / or the server 230.

[0075] The medical imaging apparatus 210 may comprise one of: an X-ray apparatus, a computed tomography (CT) scanner, a magnetic resonance imaging (MRI) scanner, an ultrasound or any other type of medical imaging apparatus that enables acquiring dynamic images of a blood vessel of a patient having been diagnosed with an aneurysm.

[0076] The medical imaging apparatus 210 may be configured with specific acquisition parameters for acquiring images of the patient comprising one or more anatomical structures of interest.

[0077] As a non-limiting example, in one or more implementations where the medical imaging apparatus 210 is implemented as a CT scanner, a CT protocol comprising preoperative retrospectively gated multidetector CT (MDCT - 64-row multi-slice CT scanner) with variable dose radiation to capture the R-R interval may be used.

[0078] As another non-limiting example, in one or more implementations where the medical imaging procedure comprises a MRI scanner, the MR protocol can comprise steady state T2 weighted fast field echo (TE = 2.6 ms, TR = 5.2 ms, flip angle 110-degree, fat suppression (SPIR), echo time 50 ms, maximum 25 heart phases, matrix 256 x 256, acquisition voxel MPS (measurement, phase and slice encoding directions) 1.56 / 1.56 / 3.00 mm and reconstruction voxel MPS 0.78

[0079] In one or more alternative implementations, the medical imaging apparatus 210 may include or may be connected to a workstation computer 215 for inter alia control of acquisition parameters and image data transmission.

[0080] Workstation Computer

[0081] The workstation computer 215 is configured to inter alia: (i) control acquisition parameters of the medical imaging apparatus to perform medical imaging; (ii) receive and process images from the medical imaging apparatus 210; and (iii) transmit the images to the server 230.

[0082] The workstation computer 215 is configured to control acquisition parameters of the medical imaging apparatus 210.

[0083] The workstation computer 215 may receive images from the medical imaging apparatus 210 in raw format and perform a tomographic reconstruction using known algorithms and software.

[0084] The implementation of the workstation computer 215 is known in the art. The workstation computer 215 may be implemented as the computing device 100 or comprise components thereof, such as the processor 110, the graphics processing unit (GPU) 111, the solid-state drive 120, the random-access memory 130, the display interface 140, and the input / output interface 150.

[0085] In one embodiment, the workstation computer 215 is configured according to the Digital Imaging and Communications in Medicine (DICOM) standard for communication and management of medical imaging information and related data.

[0086] The workstation computer 215 is connected to a server 230 over the communications network 220 via a communication link (not numbered).

[0087] In one or more alternative implementations, a workstation computer 215 may be provided together with the medical imaging apparatus 210. In one or more other implementations, the workstation computer 215 may be implemented as a mobile device such as a smartphone or a tablet.

[0088] In one or more implementations, the medical imaging apparatus 210 is part of a Picture Archiving and Communication System (PACS) for communication and management of medical imaging information and related data together with other electronic devices such as the server 230.

[0089] Server

[0090] The server 230 is configured to inter alia: (i) receive a set of images of a given patient comprising at least a portion of the one or more anatomical structures, the set of images having been acquired over at least a portion of the cardiac cycle by the medical imaging apparatus 210; (ii) segment the set of images to obtain a set of segmented images comprising a plurality of anatomical segments comprising at least a lumen and a wall of a blood vessel; (iii) calculate volumetric changes over the portion of the cardiac cycle in each of the plurality of anatomical segments comprising the lumen and the wall; and (iv) determine a type of aneurysm based on the volumetric changes of the plurality of anatomical segments comprising the lumen, the wall and the thrombus.

[0091] How the server 230 is configured to do so will be explained in more detail herein below.

[0092] The server 230 can be implemented as a conventional computer server and may comprise some or all of the components of the computing device 100 illustrated in FIG. 2. In an example of one or more implementations of the present technology, the server 230 can be implemented as a Dell™ PowerEdge™ Server running the Microsoft™ Windows Server™ operating system. Needless to say, the server 230 can be implemented in any other suitable hardware and / or software and / or firmware or a combination thereof. In theillustrated non-limiting embodiment of present technology, the server 230 is a single server. In alternative non-limiting implementations of the present technology, the functionality of the server 230 may be distributed and may be implemented via multiple servers (not illustrated).

[0093] The implementation of the server 230 is well known to the person skilled in the art of the present technology. However, briefly speaking, the server 230 comprises a communication interface (not illustrated) structured and configured to communicate with various entities (such as the workstation computer 215, for example and other devices potentially coupled to the network 220) via the communications network 220. The server 230 further comprises at least one computer processor (e.g., a processor 110 or GPU 111 of the computing device 100) operationally connected with the communication interface and structured and configured to execute various processes to be described herein.

[0094] In one or more implementations, the server 230 may be implemented as the computing device 100 or comprise components thereof, such as the processor 110, the graphics processing unit (GPU) 111, the solid-state drive 120, the random-access memory 130, the display interface 140, and the input / output interface 150.

[0095] It will be appreciated that the server 230 may provide the output of one or more processing steps to another electronic device for display, confirmation and / or troubleshooting. As a non-limiting example, the server 230 may transmit images, calculated values, results, machine learning parameters, for display on a client device configured similar to the computing device 100 such as a smart phone, tablet, and the like.

[0096] In some implementations of the present technology, the server 230 has access to the set of machine learning (ML) models 250.

[0097] Machine Learning (ML) models

[0098] The set of ML models 250 comprises inter alia a set of segmentation ML models260. ML models are referred to as models hereinafter.

[0099] Each of the set of models 250 is parametrized by inter alia model parameters and hyperparameters.

[0100] The model parameters are configuration variables of the model which are used to perform predictions, and which are estimated or learned from training data, i.e. the coefficients are chosen during learning based on an optimization strategy for outputting a prediction. The hyperparameters are configuration variables of a model which determine the structure of the initial model and how the initial model is trained.

[0101] It will be appreciated that the number of model parameters to initialize will depend on inter alia the type of model (e.g., classification or regression model), the architecture of the model (e.g., DNN, SVM, ensemble trees, etc.), and the model hyperparameters (e.g., a number of layers, type of layers, number of neurons in a NN).

[0102] In one or more implementations, the hyperparameters include one or more of: a number of hidden layers and units, an optimization algorithm, a learning rate, momentum, an activation function, a minibatch size, a number of epochs, and dropout.

[0103] Segmentation Model

[0104] The set of segmentation models 260 comprise one or more segmentation models.

[0105] The set of segmentation models 260 are configured to perform segmentation of anatomical tissues in images acquired by a medical imaging modality such as the medical imaging apparatus 210.

[0106] In one or more implementations, the set of segmentation models 260 is configured to detect all borders (i.e., delimit) and discriminate (i.e., classify) various tissue types in images comprising anatomical structures.

[0107] In one or more implementations, where the anatomical structures of interest comprise an aortic area, the set of segmentation models 260 is configured to segment the outside wall of the aorta, the inside wall of the aorta, the lumen, and the intraluminal thrombus (ILT). Thus, the segmentation model 260 may classify each pixel in an image asbeing one of: the outside wall of the aorta, the inside wall of the aorta, the lumen, and the intraluminal thrombus (ILT), and background.

[0108] In one or more implementations, the set of segmentation models 260 refers to a plurality of segmentation models 260, each configured to perform a particular segmentation task. As a non-limiting example, the segmentation models 260 may include a first segmentation model configured to perform foreground and background segmentation, a second segmentation model configured to perform semantic segmentation of lumens in aortas, and a third model configured to perform classification of pathological tissues (e.g., classification of calcified versus non-calcified tissues in the aortic wall and intraluminal thrombus (if present)). A non-limiting example of such segmentation models is described in International Patent Application No. PCT7IB2022 / 051558 entitled “METHOD AND SYSTEM FOR SEGMENTING AND CHARACTERIZING AORTIC TISSUES” filed on February 22, 2022, by the same Applicant, the content of which is hereby incorporated by reference herein.

[0109] In one or more implementations, the set of segmentation models 260 may comprises convolutional neural network layers (e.g., U-Net or V-Net based), attentionbased mechanisms (i.e., transformer-based models such as a vision transformer (ViT) model) and combinations thereof. It will be appreciated that the set of segmentation models 260 may use encoder-decoder architectures.

[0110] In one or more implementations, the set of segmentation models 260 may be based on fully convolutional neural networks (FCNs), generative adversarial networks (GANs), cascaded networks, and the like.

[0111] In one or more other implementations, the segmentation model 260 may have a ResNet-based FCN architecture. Non-limiting examples of ResNet include ResNet50 (50 layers), ResNetlOl (101 layers), ResNetl52 (152 layers), ResNet50V2 (50 layers with batch normalization), ResNetl01V2 (101 layers with batch normalization), and ResNetl52V2 (152 layers with batch normalization).

[0112] In one or more alternative implementations, the set of segmentation models 260 may be implemented based on one of: U-Net, V-Net, SegNet, AlexNet, GoogleNet, VGG, DeepLab, Mask R-CNN, and the like.

[0113] Database

[0114] The database 235 is configured to inter alia, (i) store acquisition parameters and data related to the medical imaging apparatus 210; (ii) store images acquired by medical imaging modalities such as the medical imaging apparatus 210; (iii) store data related to the set of ML models 250 including model parameters, hyperparameters, datasets, and outputs; (iv) store data related to meshes generated from the images; (v) store volumetric changes; and (vi) store data relating to classification of aneurysms.

[0115] The database 235 is configured to store images and videos. In one or more implementations, the database may store Digital Imaging and Communications in Medicine (DICOM) files, including for example the DCM and DCM30 (DICOM 3.0) file extensions. Additionally or alternatively, the database 235 may store medical image files in the Tag Image File Format (TIFF), Digital Storage and Retrieval (DSR) TIFF-based format, and the Data Exchange File Format (DEFF) TIFF-based format.

[0116] In one or more implementations, the database 235 may store ML file formats, such as .tfrecords, .csv, .npy, and .petastorm as well as the file formats used to store models, such as .pb, .pkl, .pt, or .pth. The database 235 may also store well-known file formats such as, but not limited to image file formats (e.g., .png, .jpeg, .exif, .bmp, .tiff), video file formats (e.g., .mp4, .mkv, etc), archive file formats (e.g., .zip, .gz, .tar, ,bzip2), document file formats (e.g., .docx, .pdf, .txt) or web file formats (e.g., .html).

[0117] It will be appreciated that the database 235 may store other types of data such as validation datasets (not illustrated), test datasets (not illustrated) and the like.

[0118] Communication Network

[0119] In some implementations of the present technology, the communications network 220 is the Internet. In alternative non-limiting implementations, thecommunication network 220 can be implemented as any suitable local area network (LAN), wide area network (WAN), a private communication network or the like. It should be expressly understood that implementations for the communication network 220 are for illustration purposes only. How a communication link 225 (not separately numbered) between the workstation computer 215 and / or the server 230 and / or another electronic device (not illustrated) and the communications network 220 is implemented will depend inter alia on how each of the medical imaging apparatus 210, the workstation computer 215, and the server 230 is implemented.

[0120] The communication network 220 may be used in order to transmit data packets amongst the workstation computer 215, the server 230 and the database 235. For example, the communication network 220 may be used to transmit requests between the workstation computer 215 and the server 230.

[0121] Volume Comparison and Classification Procedure

[0122] With reference to FIG. 3, there is illustrated a schematic diagram of a volume comparison and classification procedure 300 in accordance with one or more non-limiting implementations of the present technology.

[0123] The purpose of the volume comparison and classification procedure 300 is to generate volumetric meshes from segmented images of the blood vessel of the patient during at least a portion of the cardiac cycle and quantify the volumetric changes of the different anatomical structures (e.g., outer wall, lumen and / or thrombus) over time to classify aneurysms into one of a plurality of types according to the blood pressure response.

[0124] The volume comparison and classification procedure 300 comprises inter alia an image acquisition procedure 320, a segmentation procedure 330, a volume determination procedure 340 a volume change determination procedure 350, a classification procedure 360.

[0125] In one or more implementations, the volume comparison and classification procedure 300 may be executed by the server 230. In one or more alternative implementations, the volume comparison and classification procedure 300 may beexecuted by one or more computing devices in a distributed manner. As a non-limiting example, a first computing device such as the server 230 may execute at least a portion of the volume comparison and classification procedure 300 (i.e., one of the procedures) and one or more other computing devices may execute other portions of the volume comparison and classification procedure 300 (i.e., other ones of the procedures).

[0126] Image Acquisition Procedure

[0127] The image acquisition procedure 320 is configured to inter alia receive a set of images of a body of a patient acquired by the medical imaging apparatus 210.

[0128] The set of images of the body of the patient comprises at least one image of the body of a patient for a plurality of time steps during the cardiac cycle, which is a discrete representation of a signal that includes at least a portion of one or more anatomical structures of interest, having been generated using the medical imaging apparatus 210.

[0129] It will be appreciated that for 2D domain representations, image cells are referred to as “pixels”, and for 3D domain representations, image cells are referred to as “voxels”.

[0130] In one or more implementations, the set of images may be in the form of an image stack.

[0131] It will be appreciated that an image stack comprises a set of sequential images, also referred to as slices, which can be scrolled and are expected for cross-sectional studies (e.g., CT / MRI) as well as for time-resolved modalities. As a non-limiting example, an image stack may be provided in the DICOM file format.

[0132] In one or more implementations, the image stack may be in the form of a multiphase stack, where each phase of the multiphase stack may correspond to a time instance step. As a non-limiting example, each phase in the multiphase stack may correspond to a moment in the cardiac cycle of the given patient.

[0133] In one or more implementations, the set of images of the body of the patient comprise aorta(s) and / or iliac arteries.

[0134] In one or more implementations, the one or more anatomical structures in the set of images may include a thoracic area (e.g., ascending aorta, aortic arch, descending thoracic aorta) and / or abdominal aorta area (e.g., suprarenal abdominal aorta, infrarenal aorta, renal arteries, lumbar arteries) and iliac arteries (e.g., common iliac arteries, external iliac arteries, internal iliac arteries).

[0135] The image acquisition procedure 320 outputs the set of images comprising the blood vessel of the patient over at least a portion of the cardiac cycle.

[0136] Segmentation Procedure

[0137] The segmentation procedure 330 is configured to inter alia: (i) receive the set of images acquired over at least the portion of the cardiac cycle; and (ii) segment the set of images to obtain a set of segmented anatomical structures over at least the portion of the cardiac cycle.

[0138] The purpose of the segmentation procedure 330 is to segment regions of interests in the set of images of the body of the patient over the plurality of time steps such that volumetric meshes of the regions of interest may be generated for each of the plurality of time steps.

[0139] The segmentation procedure 330 uses manual and / or automatic segmentation methods to obtain a plurality of anatomical structures, which may also be referred to as segmented tissues.

[0140] In one or more other implementations, the segmentation procedure 330 may use manual segmentation techniques to obtain the segmented anatomical structures.

[0141] In one or more implementations, the segmentation procedure 330 uses a set of trained segmentation ML models 260 having been trained to segment anatomical structures in images acquired by an imaging apparatus (e.g., the medical imaging apparatus 210) to obtain one or more anatomical segments. For example, the segmentation procedure 330 may output for regions in an image, one of a plurality of classes including at least one anatomical segment and a background.

[0142] In one or more other implementations, the segmentation procedure 330 may use other types of segmentation techniques known in the art.

[0143] As a non-limiting example, the set of segmentation models 260 may have been trained to segment aortic tissues in images.

[0144] In one or more implementations, the segmentation procedure 330 obtains, for each image in the set of images of the patient, a segmented aortic area comprising one or more of an aorta and iliac arteries. In one or more implementations, the segmented aortic area comprises the lumen, the outer wall, and the intraluminal thrombus (ILT).

[0145] In the context of AAAs, the outer wall corresponds to the outermost layer of the aneurysmal aorta, the lumen corresponds to the inner open space (i.e., cavity or channel) through which blood flows, and the thrombus corresponds to a blood clot-like structure that forms on an inner surface of the aneurysm.

[0146] Additionally, the segmentation procedure 330 may segment different branches of the abdominal aorta including a celiac artery and superior and inferior mesenteric arteries, hepatic artery, splenic artery, renal arteries, and iliac arteries.

[0147] In one or more alternative implementations, the segmentation procedure 330 outputs the set of segmented images, where each pixel is categorized with a respective segmented tissue label.

[0148] In one or more implementations, the segmentation procedure 330 performs segmentation of the images of the blood vessel at a reference time, such as, as a nonlimiting example, the diastolic time (i.e., relaxed phase of the cardiac cycle).

[0149] In one or more implementations, the segmentation procedure 330 extracts the segmented tissues from the set of images to obtain at least one image per anatomical segment (e.g., lumen and outer wall). It will be appreciated that the segmented tissues may be extracted by performing masking.

[0150] In one or more implementations, a segmented thrombus may be obtained based on the segmented lumen and the segmented outer wall.

[0151] The segmentation procedure 330 outputs, for each of the set of images, one or more segmented anatomical structures.

[0152] In one or more other implementations, the segmentation procedure 330 outputs a segmented lumen, a segmented outer wall and a segmented thrombus for each phase (i.e., time step) of the cardiac cycle for the set of images.

[0153] Volume Determination Procedure

[0154] The volume determination procedure 340 is configured to inter alia', (i) receive as an input the plurality of segmented anatomical structures generated by the segmentation procedure 330; and (ii) calculate, for each of the plurality of anatomical structures, a respective volume over the plurality of time steps.

[0155] The purpose of the volume determination procedure 340 is to calculate, based on each of the outer wall, the lumen and the thrombus obtained from the segmentation procedure 330, the volumes of each of the outer wall, the lumen and the thrombus such that changes in the volume of each of the outer wall, the lumen and the thrombus may be quantified during a plurality of time steps.

[0156] It will be appreciated that different techniques may be used to calculate the volumes of the segmented structures.

[0157] In some implementations, the volume determination procedure 340 may determine the volume of a segmented anatomical structure using a voxel counting method. The volume determination procedure 340 may count the number of voxels within each of the segmented anatomical structures, and multiplying the voxel count by the volume of a single voxel, which is determined by the resolution of the imaging modality.

[0158] In one or more other implementations, the volume determination procedure 340 may determine the volume of a segmented anatomical structure using manual planimetry. The volume determination procedure 340 may trace the contour of the structure in each slice of the set of images, calculating the area enclosed by the contour in each slice, multiplying the area by the slice thickness, and summing the volumes of all slices.

[0159] In one or more alternative implementations, the volume determination procedure 340 may determine the volume of a segmented anatomical structure using 3D mesh reconstruction and volume rendering. The volume determination procedure 340 may generate a 3D mesh model of the anatomical structure from the segmented slices, using volume rendering techniques to visualize and quantify the volume, and employ software tools to determine the total volume based on the reconstructed 3D mesh.

[0160] In some implementations, the volume determination procedure 340 may determine the volume of a segmented anatomical structure using surface mesh extraction. The volume determination procedure 340 may generate a surface mesh of the segmented anatomical structure and use computational geometry techniques to calculate the volume enclosed by the mesh.

[0161] In one or more other implementations, the volume determination procedure 340 may determine the volume of a segmented anatomical structure using mathematical models. The volume determination procedure 340 may apply mathematical models to estimate the volume based on geometric approximations of the anatomical structure, such as fitting an ellipsoid or other geometric shape to the structure.

[0162] In one or more alternative implementations, the volume determination procedure 340 may determine the volume of a segmented anatomical structure by integrating cross- sectional areas. The volume determination procedure 340 may calculate the cross-sectional area of the segmented structure in each slice and integrate the areas over the length of the structure to obtain the volume.

[0163] The volume determination procedure 340 may determine the volume of a segmented anatomical structure using an optical flow algorithm. The optical flow algorithm may analyze the motion of pixels in the set of images over time. The optical flow algorithm may estimate the flow of pixels between successive images, which can be used to track and segment moving anatomical structures. The optical flow algorithm may calculate the structure's volume can be calculated by assessing the changes in the segmented region's shape and size across the image sequence.

[0164] In one or more alternative implementations, the volume determination procedure 340 may determine the volume of a segmented anatomical structure using specialized software tools, such as, but not limited to, OsiriX or 3D Slicer, which provides built-in functions for volume calculation, which may combine multiple techniques like automated segmentation and 3D reconstruction to provide accurate volume measurements.

[0165] For an abdominal aorta, the volume meshes may be defined as a geometry extending from the distal renal to the iliac bifurcation. In one or more implementations, the wall volume may be defined as the volume enclosed in the surface segmenting the outer wall of the aneurysm.

[0166] In one or more implementations, the volume determination procedure 340 evaluates the quality of the mesh using criteria such as, but not limited to, element aspect ratio, skewness, and edge lengths. The volume determination procedure 340 may also improve the mesh quality by adjusting nodes, edge lengths, and by optimizing the element distribution throughout the volume, by using techniques such as, but not limited to, smoothing and relaxation.

[0167] In one or more implementations, the volume determination procedure 340 validates the volume mesh to ensure it accurately represents the segmented anatomical structures. This could involve techniques such as, but not limited to, comparing it to the original medical images, checking for any inconsistencies in the mesh geometry, or manually review and adjust the mesh to correct any inaccuracies.

[0168] The volume determination procedure 340 outputs, for each segmented anatomical structure, a 3D geometrical volume mesh.

[0169] In one or more implementations, the volume determination procedure 340 outputs an outer wall volume mesh and a lumen volume mesh of the blood vessel at each of the plurality of time steps of the cardiac cycle.

[0170] In some implementations, the volume determination procedure 340 calculates the volume of the outer wall volume mesh, and the volume of the lumen mesh for each time point (i.e., phase) of the cardiac cycle. For each time step, the volume determinationprocedure 340 may calculates the volume of each mesh element and calculate a sum of the volume of all its constituent elements to obtain the total volume of the respective mesh.

[0171] In one or more other implementations, the volume of the outer wall volume mesh, and the volume of the lumen mesh for each time point (i.e., phase) of the cardiac cycle may be calculated by the volume change determination procedure 350.

[0172] It will be appreciated that the thrombus mesh may be determined based on the outer wall mesh and the lumen mesh of the blood vessel (e.g., abdominal aorta).

[0173] Volume Change Determination Procedure

[0174] The volume change determination procedure 350 receives the volumes for each of the plurality of time steps of the cardiac cycle.

[0175] The volume change determination procedure 350 may receive or determine the total lumen volume and the total outer wall volume for each of the plurality of time steps (i.e., each phase).

[0176] In one or more implementations, the volume change determination procedure 350 calculates the volume changes of each of the lumen volume mesh, the wall volume mesh and the thrombus volume mesh over the plurality of time steps representing a portion of the cardiac cycle. In some implementations, the plurality of time steps may correspond to the totality of the cardiac cycle.

[0177] In one or more implementations, the cardiac cycle is divided into at least 10- time steps (i.e., phases).

[0178] In one or more implementations, the volume change determination procedure 350 determines the volume change of each segmented structure over time by comparing the calculated volumes at each time point to a reference volume corresponding to a selected point in time. The selected point in time may correspond to the diastolic time. The diastolic time may be defined as the time point where the aneurysm volume (i.e., wall volume) is minimal (i.e., at its lowest value)

[0179] In one or more implementations, the volume change determination procedure 350 performs this calculation for all available time steps to analyze the volume changes in the different anatomical regions.

[0180] The volume change determination procedure 350 outputs lumen volumetric changes, wall volumetric changes and thrombus volumetric changes over time.

[0181] In one or more implementations, the volumetric changes are quantified in milliliters (mL). In one or more other implementations, the volumetric changes may be normalized and / or calculated according to a different unit or scale.

[0182] It will be appreciated that the volumetric changes may have negative values and positive values. As a non-limiting example, the lumen volume may have negative values during the cardiac cycle.

[0183] In one or more implementations, the lumen volumetric changes, the wall volumetric changes and the thrombus volumetric changes are output as respective vectors, where each element of the vector represents a different time step.

[0184] In one or more implementations, the volume change determination procedure 350 generates, based on the lumen volumetric changes, the wall volumetric changes and the thrombus volumetric changes, a graphical representation.

[0185] The graphical representation may be a 2D graph showing the volumetric changes (y-axis) of each of the lumen, wall and thrombus in function of time (x-axis).

[0186] Classification Procedure

[0187] The classification procedure 360 receives as an input the set of volume changes for different anatomical regions over time.

[0188] In one or more implementations, the classification is based on the lumen volumetric changes, the wall volumetric changes and the thrombus volumetric changes over the plurality of time steps.

[0189] In one or more implementations, the classification procedure 360 receives the lumen volumetric changes, the wall volumetric changes and the thrombus volumetric changes over the plurality of time steps. Each of the lumen volumetric changes, the wall volumetric changes and the thrombus volumetric changes may be represented in the form of vectors.

[0190] The classification procedure 360 then classifies, based on one or more of the lumen volumetric changes, the wall volumetric changes and the thrombus volumetric changes over the plurality of time steps, the aneurysm as one of four types of aneurysms.

[0191] The classification procedure 360 classifies the aneurysm based on a comparison of the lumen volumetric changes, the wall volumetric changes and the thrombus volumetric changes over the plurality of time steps.

[0192] In one or more implementations, the aneurysm is classified based on the relative values between the lumen volumetric changes, the wall volumetric changes and the thrombus volumetric changes over the plurality of time steps.

[0193] In one or more implementations, the lumen volumetric change, and wall volumetric change are plotted on a graph for each phase of the cardiac cycle together with the thrombus volumetric changes, defined as a difference between the wall and the lumen volumes.

[0194] The classification procedure 360 applies different classification criteria to the volume changes over time of the lumen, the outer wall and the thrombus to classify the aneurysm as one of four types of AAA.

[0195] The classification procedure 360 classifies the aneurysm as being of type I or the first type of aneurysm based on: (i) negative lumen volume changes (i.e., below zero) during at least a first portion of the plurality of time steps; and (ii) thrombus volumetric changes being above the wall volumetric changes and the lumen volumetric changes during at least a second portion of the cardiac cycle.

[0196] It should be understood that the first portion and the second portion of the cardiac cycle may correspond to the same portion of the cardiac cycle, or time steps in the first portion of the cardiac cycle may intersect with the time steps in the second portion of the cardiac cycle.

[0197] In one or more implementations, the first portion of the plurality of time steps corresponds to a majority of the plurality of time steps (i.e., 50% + 1).

[0198] In one or more implementations, type I corresponds to a stiff wall with negative lumen expansion, which may in time put the aneurysm at risk for wall delamination or dissection.

[0199] FIG. 4 illustrates a first plot 420 of the thrombus volumetric changes 424, the outer wall volumetric changes 424, the lumen volumetric changes 426 (mL) over ten-time steps for the first type of aneurysm.

[0200] In addition to FIG. 4, reference is also made to FIG. 5 which shows the volumetric change of the lumen, the wall and the thrombus for two patients exhibiting signs of type I aneurysms. On the curves 510 associated with patient 1, the volumetric change of the lumen is negative, with a negative peak at the fourth time step, indicating a contraction of the lumen. Additionally, the volumetric change of the thrombus is higher than the volumetric change of the wall. On the curves 520 associated with patient 2, the volumetric change of the lumen is also mostly negative. The volumetric thrombus change is higher than the wall volume change.

[0201] The classification procedure 360 classifies the aneurysm as being of type II or the second type of aneurysm based on: (i) minimal positive lumen volumetric changes (i.e., within a first threshold range); (ii) the wall volume changes being one of: above the thrombus volumetric changes or similar to the thrombus volumetric changes (i.e. within a second threshold range).

[0202] In one or more implementations, the first threshold range may correspond to values oscillating around zero.

[0203] In one or more implementations, the minimal positive lumen volumetric changes may be based on a first threshold range, and the values of the wall volumetric changes and the thrombus volumetric changes may be within a second threshold range of each other. It will be appreciated that the first threshold range and the second threshold range may be for respective portions of the plurality of time steps.

[0204] In one or more implementations, type II corresponds to an aneurysm where the lumen exhibits very little expansion.

[0205] FIG. 4 illustrates a second plot 440 of the thrombus volumetric changes 444, the outer wall volumetric changes 442, and the lumen volumetric changes 446 in mb over tentime steps for the second type of aneurysm.

[0206] In addition to FIG. 4, reference is also made to FIG. 6 which shows the volumetric change of the lumen, the wall and the thrombus for five patients exhibiting signs of type II aneurysms. On the curves 610 associated with patient 3, the volumetric change of the lumen is positive and the lowest of the three curves. On the curves 620 associated with patient 4, the volumetric change of the lumen is the lowest of the three curves. The volumetric change of the wall is higher than the volumetric change of the thrombus. On the curves 630 associated with patient 5, the volumetric change of the lumen is the lowest of the three curves and the volumetric change of the wall is the highest of the three curves. On the curves 640, associated with patient 6, the volumetric change of the lumen is the lowest of the three curves and the volumetric change of the wall is the highest of the three curves. On the curves 650, associated with patient 7, the volumetric change of the lumen is the lowest of the three curves. Both curves of the volumetric change of the wall and thrombus are equal around the second time step and the seventh time step.

[0207] The classification procedure 360 classifies the aneurysm as being of type III or third type based on: (i) lumen volumetric changes being positive (i.e., above zero); and (ii) the lumen volumetric changes being similar to the thrombus volumetric changes (i.e., within a third threshold range).

[0208] It will be appreciated that the third threshold range may be defined for at least a third portion of the plurality of time steps of the cardiac cycle.

[0209] In other words, type III is characterized by the lumen volume increase and the thrombus volume change similar to the lumen volume change.

[0210] In one or more implementations, type III is a transition type characterized by some lumen expansion and wall expansion with the thrombus experiencing expansion.

[0211] FIG. 4 illustrates a third plot 460 of the thrombus volumetric changes 464, the outer wall volumetric changes 462, and the lumen volumetric changes 466 in mb over tentime steps for the third type of aneurysm.

[0212] In addition to FIG. 4, reference is also made to FIG. 7 which shows the volumetric change of the lumen, the wall and the thrombus for three patients exhibiting signs of type III aneurysms. On plot 710 associated with patient 8, the volumetric change of the wall is the highest of the three curves. The curves of the volumetric change of the lumen and the thrombus cross at different time steps because their values are similar. On plot 720 associated with patient 9, the volumetric change of the wall is the highest of the three curves. The curves of the volumetric change of the lumen and the thrombus cross at different time steps because their values are similar. On the plot 730 associated with patient 10, the volumetric change of the wall is the highest curve. The curve of the volumetric change of the thrombus is lower than the curve of the volumetric curve of the lumen, except when they are both equal around the seventh time step.

[0213] The classification procedure 360 classifies the aneurysm as being of type IV or the fourth type based on: (i) lumen volumetric changes being positive (i.e., above zero); (ii) lumen volumetric changes being within a fourth threshold range of the wall volumetric changes; and (iii) the thrombus volumetric changes being negative (i.e. below zero) for one or more time steps of the plurality of time steps of the cardiac cycle.

[0214] It will be appreciated that the fourth threshold range may be defined for at least a fourth portion of the plurality of time steps of the cardiac cycle.

[0215] In other words, type IV corresponds to a positive relative lumen volume change and wall volume change that are above a third positive threshold. Additionally, type IV corresponds to a difference between the lumen volume change and the wall volume change below a sixth positive threshold.

[0216] In one or more implementations, type IV is characterized by lumen volume changes that match or exceed wall volume changes, while the thrombus exhibits little deformation or in some cases the thrombus volume decreases during the cardiac cycle.

[0217] In one or more implementations, type IV is associated with the risk of rupture of the aneurysm due to locally compressed thrombus that may enable the formation of fissures.

[0218] FIG. 4 illustrates a fourth plot 480 of the thrombus volumetric changes 486, the outer wall volumetric changes 482, and the lumen volumetric changes 484 in mb over tentime steps for the fourth type of aneurysm.

[0219] In addition to FIG. 4, reference is also made to FIG. 8 which shows the volumetric change of the lumen, the wall and the thrombus for four patients exhibiting signs of type IV aneurysms. On the plot 810 associated with patient 11, the volumetric change of the thrombus is negative around the seventh time step. The volumetric change of the lumen curve is below the volumetric change of the wall curve, except around the seventh time step where it exceeds it. The volumetric change of the lumen curve touches the volumetric change of the thrombus curve from the zeroth to around the fourth time step. On the plot 820 and 830 associated with patient 12, the volumetric change of the thrombus is the lowest of the three curves and it is negative around the second time step for the curves 820, and around the first- and eighth-time step for plot 830. The volumetric change of the lumen is mainly lower or equal to the volumetric change of the wall, except around the first-time step, where the volumetric change of the lumen is higher than the volumetric change of the wall. On the plot 840 associated with patient 13, the volumetric change of the thrombus is the lowest curve and is negative around the seventh time step. The volumetric change of the lumen is lower than the volumetric change of the wall before around the sixth time step; after the sixth time step, the volumetric change of the lumen ishigher than the volumetric change of the wall. On the plot 850, associated with patient 14, the volumetric change of the thrombus is negative and the lowest of the three curves. The volumetric change of the lumen is higher than the volumetric change of the wall.

[0220] In one or more implementations, type IV is characterized by the lumen volume increase that is the same or higher than the wall volume increase and the minimum or negative thrombus volume change. The negative change can be temporary and does not have to cover the whole cardiac cycle.

[0221] In one or more implementations, the diameter is generally increasing from type I to type IV.

[0222] In one or more implementations, the lumen volume increases from negative in type I to positive in type IV. Wall volume change increases from type I to type IV. The thrombus volume change decreases and is the highest for type II and negative for type IV.

[0223] In one or more implementations, type I patients show a small wall volume change in contrast to the type IV patients, where the changes in wall volume are about three times higher than for type I. The wall volume changes for type II and III are about twice higher than the wall volume change for type I.

[0224] In one or more implementations, the classification is based on the average lumen volumetric change and the average thrombus volumetric change over at least some of the plurality of time steps.

[0225] In this case, the method 300 further comprises a step of calculating the average thrombus volumetric change based on the previously determined thrombus volumetric changes and the average lumen volumetric change based on the previously determined lumen volumetric changes. Each of the average lumen volumetric changes and the average thrombus volumetric changes may be represented in the form of vectors.

[0226] It should be understood that the average thrombus volumetric change and the average lumen volumetric change may be determined over the plurality of time steps, or only over a portion of the plurality of time steps. For example, the average thrombusvolumetric change and the average lumen volumetric change may be calculated over a complete cardiac cycle. In another example, the average thrombus volumetric change and the average lumen volumetric change may be calculated over a portion of the cardiac cycle.

[0227] The classification procedure 360 then classifies, based the average thrombus volumetric change and the average lumen volumetric change over the plurality of time steps, the aneurysm as one of the four types of aneurysms.

[0228] The aneurysm is classified as type I when the average thrombus volumetric change is at least equal to the average lumen volumetric change, i.e., equal to or greater than the average lumen volumetric change, and the average lumen volumetric change is less than a first change threshold.

[0229] The aneurysm is classified as type II when the average thrombus volumetric change is at least equal to the average lumen volumetric change, i.e., equal to or greater than the average lumen volumetric change, and the average lumen volumetric change is at least equal to the first change threshold, i.e., equal to or greater than the first change threshold.

[0230] The aneurysm is classified as type III when the average thrombus volumetric change is less than the average lumen volumetric change and the average thrombus volumetric change is at least equal to a second change threshold, i.e., equal to or greater than the second change threshold.

[0231] The aneurysm is classified as type IV when the average thrombus volumetric change is less than the average lumen volumetric change and the average thrombus volumetric change is less than the second change threshold.

[0232] In some embodiments, a type I aneurysm is considered as an aneurysm for which the average growth is not important or with substantially no growth. For example, a type I aneurysm may be an aneurysm for which the average growth is significantly below an average value.

[0233] In some embodiments, a type II aneurysm is considered as an aneurysm for which the average growth is below an expected, average or acceptable value. A type III aneurysm is considered as an aneurysm for which the average growth is above the expected, average or acceptable value, but not critical.

[0234] In other embodiments, both a type II aneurysm and a type III aneurysm are aneurysms for which the average growth is around an expected, average or acceptable value. For example, a type II aneurysm and / or a type III may have an average growth that is below the expected, average or acceptable value, but not significantly below the expected, average or acceptable value. In another example, a type II aneurysm and / or a type III may have an average growth that is above the expected, average or acceptable value, but not significantly above the expected, average or acceptable value.

[0235] A type IV aneurysm is considered as an aneurysm for which the average growth is critical. For example, a type IV aneurysm may have a an average growth that is significantly above an expected, average or acceptable value.

[0236] Fig. 10 illustrates an exemplary graph of an average lumen volumetric change as a function of an average thrombus volumetric change. In the illustrated graph, each dot corresponds to a respective aneurysm.

[0237] This graph is separated into four regions each being associated with a respective aneurysm type. The first region is associated with type I aneurysm and corresponds to the region for which the average thrombus volumetric change is at least equal to the average lumen volumetric change and the average lumen volumetric change is less than the first change threshold.

[0238] The second region is associated with type II aneurysm and corresponds to the region for which the average thrombus volumetric change is at least equal to the average lumen volumetric change and the average lumen volumetric change is at least equal to the first change threshold.

[0239] The third region is associated with type III aneurysm and corresponds to the region for which the average thrombus volumetric change is less than the average lumenvolumetric change and the average thrombus volumetric change is at least equal to a second change threshold.

[0240] The fourth region is associated with type IV aneurysm and corresponds to the region for which the average thrombus volumetric change is less than the average lumen volumetric change and the average thrombus volumetric change is less than the second change threshold.

[0241] In one or more implementations, the classification is based on the average lumen volumetric change percentage and the average thrombus volumetric change percentage.

[0242] In this case, the method 300 further comprises the steps of:

[0243] dividing the average thrombus volumetric change by an initial thrombus volumetric change, thereby obtaining a thrombus volumetric change percentage; and

[0244] dividing the average lumen volumetric change by an initial lumen volumetric change, thereby obtaining a lumen volumetric change percentage,

[0245] In one or more implementations, the initial thrombus volumetric change and the initial lumen volumetric change are each associated with the first or initial one of the plurality of time steps.

[0246] The classification procedure 360 then classifies, based the average thrombus volumetric change percentage and the average lumen volumetric change percentage, the aneurysm as one of the four types of aneurysms.

[0247] The aneurysm is classified as type I when the thrombus volumetric change percentage is at least equal to the lumen volumetric change percentage, i.e., equal to or greater than the lumen volumetric change percentage, and the lumen volumetric change percentage is less than a first percentage threshold.

[0248] The aneurysm is classified as type II when the thrombus volumetric change percentage is at least equal to the lumen volumetric change percentage, i.e., equal to or greater than the lumen volumetric change percentage, and the lumen volumetric changepercentage is at least equal to the first percentage threshold, i.e., equal to or greater than the first percentage threshold.

[0249] The aneurysm is classified as type III when the thrombus volumetric change percentage is less than the lumen volumetric change percentage and the thrombus volumetric change percentage is at least equal to a second percentage threshold, i.e., equal to or greater than the second percentage threshold.

[0250] The aneurysm is classified as type IV when the thrombus volumetric change percentage is less than the lumen volumetric change percentage and the thrombus volumetric change percentage is less than the second percentage threshold.

[0251] Fig. 11 illustrates an exemplary graph of an average lumen volumetric change percentage as a function of an average thrombus volumetric change percentage. In the illustrated graph, each dot corresponds to a respective aneurysm.

[0252] This graph is separated into four regions each being associated with a respective aneurysm type. The first region is associated with type I aneurysm and corresponds to the region for which the thrombus volumetric change percentage is at least equal to the lumen volumetric change percentage and the lumen volumetric change percentage is less than the first percentage threshold.

[0253] The second region is associated with type II aneurysm and corresponds to the region for which the thrombus volumetric change percentage is at least equal to the lumen volumetric change percentage and the lumen volumetric change percentage is at least equal to the first percentage threshold.

[0254] The third region is associated with type III aneurysm and corresponds to the region for which the thrombus volumetric change percentage is less than the lumen volumetric change percentage and the thrombus volumetric change percentage is at least equal to the second percentage threshold.

[0255] The fourth region is associated with type IV aneurysm and corresponds to the region for which the thrombus volumetric change percentage is less than the lumenvolumetric change percentage and the thrombus volumetric change percentage is less than the second percentage threshold.

[0256] The classification procedure 360 outputs the type of the AAA.

[0257] In one or more implementations, the classification procedure 360 outputs a plot of the volumetric changes of the lumen, wall and thrombus with the type aneurysm classification and an explanation of the classification (i.e., markers and text).

[0258] In one or more implementations, the classification procedure 360 outputs a graph of an average lumen volumetric change as a function of an average thrombus volumetric change, such as the graph illustrated in Fig. 10, in which four regions (each being associated with a respective type of aneurysm) are identified. The graph further comprises a dot positioned within one of the four regions to visually indicate the type of the aneurysm.

[0259] In one or more implementations, the classification procedure 360 outputs a graph of an average lumen volumetric change percentage as a function of an average thrombus volumetric change percentage, such as the graph illustrated in Fig. 11, in which four regions (each being associated with a respective type of aneurysm) are identified. The graph further comprises a dot positioned within one of the four regions to visually indicate the type of the aneurysm.

[0260] Method Description

[0261] FIG. 9 illustrates a flowchart of a method 900 of classifying an aneurysm, the method 900 being executed in accordance with one or more non-limiting implementations of the present technology.

[0262] In one or more implementations, the server 230 comprises at least processor such as the processor 110 and / or the GPU 111 operatively connected to a non-transitory computer readable storage medium such as the solid-state drive 120 and / or the randomaccess memory 130 storing computer-readable instructions. The at least one processor,upon executing the computer-readable instructions, is configured to or operable to execute the method 900.

[0263] According to processing step 902, the at least one processor receives a set of images representing the blood vessel of the given patient over at least a portion of the cardiac cycle, the set of images having been acquired by a medical imaging apparatus.

[0264] According to processing step 904, the at least one processor segments the set of images to obtain a segmented outer wall of the aneurysm and a segmented lumen at a plurality of time steps over at least the portion of the cardiac cycle.

[0265] According to processing step 906, the at least one processor calculates, based on the segmented outer wall and the segmented lumen over the plurality of time steps, wall volumetric changes and lumen volumetric changes over the plurality of time steps.

[0266] It will be appreciated that the wall volumetric changes and the lumen volumetric changes may be determined using various techniques.

[0267] In one or more implementations, the at least one processor generates a lumen mesh and an outer wall mesh at each of the plurality of time steps based respectively on the segmented lumen and segmented outer wall to determine the volumes of the lumen and outer wall.

[0268] In one or more other implementations, other methods for determining the volumes of the segmented anatomical structures such as one or more of voxel counting, manual planimetry, volume rendering, surface mesh extraction, mathematical models, optical flow algorithm or specialized medical imaging software may be used.

[0269] According to processing step 908, the at least one processor calculates, based on the lumen volumetric changes and the outer wall volumetric changes, thrombus volumetric changes over the plurality of time steps.

[0270] In one or more implementations, the at least one processor calculates the thrombus volumetric changes based on a difference between the lumen volumetric changes and the outer wall volumetric changes.

[0271] According to processing step 910, the at least one processor classifies, based at least on the lumen volumetric changes and the thrombus volumetric changes, the aneurysm as one of a first type, a second type, a third type and a fourth type.

[0272] In one or more implementations, the at least one processor classifies the aneurysm as the first type in response to: the lumen volumetric changes being negative over at least a first portion of the plurality of time steps.

[0273] The at least one processor classifies the aneurysm as the second type in response to: the lumen volumetric changes being within a first threshold range, and the wall volumetric changes and the thrombus volumetric changes being within a second threshold range.

[0274] The at least one processor classifies the aneurysm as the third type in response to: the lumen volumetric changes and the thrombus volumetric changes being within a third threshold range.

[0275] The at least one processor classifies the aneurysm as the fourth type in response to: the lumen volumetric changes being within a fourth threshold range of the outer wall volumetric changes; and the thrombus volumetric changes being negative for one or more time steps of the plurality of time steps.

[0276] In one or more implementations, the at least one processor further calculates the average thrombus volumetric change and the average lumen volumetric change, and classifies the aneurysm as being one of the four types based on the average thrombus volumetric change, the average lumen volumetric change and two change thresholds.

[0277] The at least one processor classifies the aneurysm as the first type in response to: the average thrombus volumetric change being at least equal to the average lumen volumetric change and the average lumen volumetric change being less than the first change threshold.

[0278] The at least one processor classifies the aneurysm as the second type in response to: the average thrombus volumetric change being at least equal to the average lumenvolumetric change and the average lumen volumetric change being at least equal to the first change threshold.

[0279] The at least one processor classifies the aneurysm as the third type in response to: the average thrombus volumetric change being less than the average lumen volumetric change and the average thrombus volumetric change being at least equal to a second change threshold.

[0280] The at least one processor classifies the aneurysm as the fourth type in response to: the average thrombus volumetric change being less than the average lumen volumetric change and the average thrombus volumetric change being less than the second change threshold.

[0281] In one or more implementations, the at least one processor further calculates a thrombus volumetric change percentage by dividing the average thrombus volumetric change by an initial thrombus volumetric change, and a lumen volumetric change percentage by dividing the average lumen volumetric change by an initial lumen volumetric change. The at least one processor then classifies the aneurysm as being one of the four types based on the average thrombus volumetric change percentage, the average lumen volumetric change percentage and two percentage thresholds.

[0282] The at least one processor classifies the aneurysm as the first type in response to: the thrombus volumetric change percentage being at least equal to the lumen volumetric change percentage and the lumen volumetric change percentage being less than the first percentage threshold.

[0283] The at least one processor classifies the aneurysm as the second type in response to: the thrombus volumetric change percentage being at least equal to the lumen volumetric change percentage and the lumen volumetric change percentage being at least equal to the first percentage threshold.

[0284] The at least one processor classifies the aneurysm as the third type in response to: the thrombus volumetric change percentage being less than the lumen volumetricchange percentage and the thrombus volumetric change percentage being at least equal to the second percentage threshold.

[0285] The at least one processor classifies the aneurysm as the fourth type in response to: the thrombus volumetric change percentage being less than the lumen volumetric change percentage and the thrombus volumetric change percentage being less than the second percentage threshold.

[0286] Experimental Results

[0287] Multi-phase electrocardiographic (ECG)-gated computed tomographic angiography (CT) images of fourteen patients were obtained from Peter Lougheed Hospital in Calgary, Canada. Patients were selected as representative cases from two different studies: one study included patients that underwent surgical intervention, and the second study was a retrospective study studying AAA growth. The geometries of the aortic wall and lumen were segmented from CT images at diastolic time. The whole geometry extending from distal renal to iliac bifurcation was used. The geometries during the subsequent phases were obtained by tracing the changes in wall and lumen position by a custom optical flow algorithm (reference Satriano 2015, 2018). Wall, lumen, and thrombus volumes were calculated from the full geometry at ten evenly spread phases of the cardiac cycle. An optical flow algorithm is a technique used to compute motion fields from sequential images. The underlying principle of an optical flow algorithm is that the intensity of a pixel or voxel remains constant between consecutive images, but its position might change. A displacement field is calculated between a same pixel or voxel from one time frame to another in order to compute deformation of consecutive images, and thus, the nodal displacement of every pixel or voxel. This method can be used on 2D and 3D images.

[0288] Diastolic time was defined as the time when the aneurysm volume (wall volume) is minimal. The wall volume was defined as the volume of the surface segmenting the outer wall of AAA. Thrombus volume, for this study, was defined as the difference between the wall and lumen volumes, where there is no thrombus, the volume is calculated as the difference between the wall and the lumen surfaces.

[0289] For five patients that underwent open surgery, ex- vivo specimens were collected and analyzed their mechanical properties. The uniaxial test was used to find the yield value of a wall specimen before failure. The biaxial test was used to find the stiffness of the specimens. Stiffness was obtained for the low-strain part of the curve (LTM) and separately for the high strain of the curve (HTM). The details of how the tests are performed are described in detail for example in Forneris et al. (2021).

[0290] For five patients with a surveillance scan gap extending one year, the change in wall volume were determined over the surveillance period. The wall volume change (prorated to 1 year when the scans if necessary) defined growth of the AAA.

[0291] Patients' observations and outcomes were obtained by inspecting ex-vivo specimens, and from clinical charts.

[0292] TABLE I shows information of the fourteen patients for this study:

[0293] TABLE II shows median characteristics for each AAA type.

[0294] In Table II, the diameter is generally increasing from Type I to Type IV but varies significantly within each type.

[0295] In Table II, the diameter is generally increasing from Type I to Type IV but varies significantly within each type.

[0296] The same results are for the maximum thickness of ILT. Change in the aortic volume, or growth, shows an interesting tendency.

[0297] The lumen volume increases from negative in Type I to positive in Type IV. Wall volume change increases from Type I to Type IV. The thrombus volume change decreases and is the highest for Type II and negative for Type IV.

[0298] The Type I patients showed a small wall volume change in contrast to the Type IV patients, where the changes in wall volume were about 3 times higher than for Type I. The wall volume changes for Types II and III were about twice higher than the wall volume change for Type I.

[0299] Five of the fourteen patients underwent open surgery, for which the mechanical properties of the ex-vivo specimens were analyzed. One patient fitting into the Type I category showed very stiff mechanical properties of the wall relative to other types. The patients showed a decreasing tendency in stiffness and yield from Type I to Type IV.

[0300] The growth tends to be negative for Type I, mixed in Type II, and high in Type IV.

[0301] One patient that fit in the Type I category was showing delamination of the wall during specimen processing after tissue explant. One patient’s AAA who fit the Type IV category rupture immediately after the scan, which was confirmed during surgery (Forneris et al., 2020). One patient’s AAA that fits the Type III category ruptured within three years from the scan.

[0302] In some cases, what are believed to be helpful examples of modifications to the present technology may also be set forth. This is done merely as an aid to understanding, and, again, not to define the scope or set forth the bounds of the present technology. These modifications are not an exhaustive list, and a person skilled in the art may make other modifications while nonetheless remaining within the scope of the present technology.Further, where no examples of modifications have been set forth, it should not be interpreted that no modifications are possible and / or that what is described is the sole manner of implementing that element of the present technology.

[0303] Modifications and improvements to the above-described implementations of the present technology may become apparent to those skilled in the art. The foregoing description is intended to be exemplary rather than limiting.

Claims

1. CLAIMS1. A method for classifying an aneurysm in a blood vessel of a given patient having been diagnosed with the aneurysm, the method being executed by at least one processor, the method comprising: receiving a set of images representing the blood vessel of the given patient over at least a portion of a cardiac cycle, the set of images having been acquired by a medical imaging apparatus, the blood vessel comprising the aneurysm; segmenting the set of images to obtain at least a segmented outer wall of the aneurysm and a segmented lumen at a plurality of time steps over at least the portion of the cardiac cycle; calculating, based on the segmented outer wall and the segmented lumen over the plurality of time steps, wall volumetric changes and lumen volumetric changes; calculating, based on the lumen volumetric changes and the outer wall volumetric changes, thrombus volumetric changes over the plurality of time steps; classifying, based on at least the lumen volumetric changes and the thrombus volumetric changes, the aneurysm as one of: a first type of aneurysm, a second type of aneurysm, a third type of aneurysm and a fourth type of aneurysm.

2. The method of claim 1, wherein said classifying is further based on the outer wall volumetric changes, the aneurysm being classified as one of: the first type of aneurysm in response to the lumen volumetric changes being negative over a majority of the plurality of time steps,the second type of aneurysm in response to: the lumen volumetric changes being within a first threshold range, and the outer wall volumetric changes and the thrombus volumetric changes being within a second threshold range, the third type of aneurysm in response to: the lumen volumetric changes and the thrombus volumetric changes being within a third threshold range; and the fourth type of aneurysm in response to: the lumen volumetric changes being within a fourth threshold range of the outer wall volumetric changes, and the thrombus volumetric changes being negative for at least one of the plurality of time steps.

3. The method of claim 1, further comprising calculating an average thrombus volumetric change based on the thrombus volumetric changes and an average lumen volumetric change based on the lumen volumetric changes, said classifying comprising classifying, based on the average thrombus volumetric change and the average lumen volumetric change, the aneurysm as one of: the first type of aneurysm when the average thrombus volumetric change is at least equal to the average lumen volumetric change and the average lumen volumetric change is less than a first change threshold; the second type of aneurysm when the average thrombus volumetric change is at least equal to the average lumen volumetric change and the average lumen volumetric change is at least equal to the first change threshold; the third type of aneurysm when the average thrombus volumetric change is less than the average lumen volumetric change and the average thrombus volumetric change is at least equal to a second change threshold; and the fourth type of aneurysm when the average thrombus volumetric change is less than the average lumen volumetric change and the average thrombus volumetric change is less than the second change threshold.

4. The method of claim 3, wherein an initial thrombus volumetric change and an initial lumen volumetric change are each associated with a first one of the plurality of time steps, the method further comprising: dividing the average thrombus volumetric change by the initial thrombus volumetric change, thereby obtaining a thrombus volumetric change percentage; and dividing the average lumen volumetric change by the initial lumen volumetric change, thereby obtaining a lumen volumetric change percentage, said classifying comprising classifying, based on the thrombus volumetric change percentage and the lumen volumetric change percentage, the aneurysm as one of: the first type of aneurysm when the thrombus volumetric change percentage is at least equal to the lumen volumetric change percentage and the lumen volumetric change percentage is less than a first percentage threshold; the second type of aneurysm when the thrombus volumetric change percentage is at least equal to the lumen volumetric change percentage and the lumen volumetric change percentage is at least equal to the first percentage threshold; the third type of aneurysm when the thrombus volumetric change percentage is less than the lumen volumetric change percentage and the thrombus volumetric change percentage is at least equal to a second percentage threshold; and the fourth type of aneurysm when the thrombus volumetric change percentage is less than the lumen volumetric change percentage and the thrombus volumetric change percentage is less than the second percentage threshold.

5. The method of any one of claims 1 to 4, wherein the first type of aneurysm is indicative of wall delamination.

6. The method of any one of claims 1 to 5, wherein the fourth type of aneurysm is indicative of an impending rupture of the aneurysm.

7. The method of any one of claims 1 to 6, wherein said calculating, based on the lumen volumetric changes and the outer wall volumetric changes, the thrombus volumetric changes over the plurality of time steps comprises: calculating a difference between the outer wall volumetric changes and the lumen volumetric changes.

8. The method of any one of claims 1 to 7, wherein the at least the first portion comprises a majority of the plurality of time steps.

9. The method of any one of claims 1 to 8, wherein said calculating, based on the segmented outer wall and the segmented lumen over the plurality of time steps, the wall volumetric changes and the lumen volumetric changes comprises: generating, based on the segmented outer wall over the plurality of time steps, outer wall meshes over the plurality of time steps; calculating volumes of the outer wall meshes over the plurality of time steps; determining the wall volumetric changes based on the volumes of the outer wall meshes over the plurality of time steps; generating, based on the segmented lumen over the plurality of time steps, segmented lumen meshes over the plurality of time steps; calculating volumes of the outer wall meshes over the plurality of time steps; and determining the lumen volumetric changes based on the volumes of the lumen meshes over the plurality of time steps.

10. The method of claim 9, wherein said determining the lumen volumetric changes based on the volumes of the lumen meshes over the plurality of time steps and determining the wall volumetric changes based on the volumes of the outer wall meshes over the plurality of time steps comprises determining the lumen volumetric changes based on thevolumes of the lumen meshes over the plurality of time steps and determining the wall volumetric changes based on the volumes of the outer wall meshes over ten evenly spaced time steps of the cardiac cycle.

11. The method of claim 10, said determining the lumen volumetric changes based on the volumes of the lumen meshes over the plurality of time steps and determining the wall volumetric changes based on the volumes of the outer wall meshes over the plurality of time steps are relative to a diastolic time of the cardiac cycle.

12. A system for classifying an aneurysm in a blood vessel of a given patient having been diagnosed with the aneurysm, the system comprising: a processor; a non-transitory storage medium operatively connected to the at least one processor, the non-transitory storage medium storing computer-readable instructions thereon; the at least one processor, upon executing the computer-readable instructions, being configured for: receiving a set of images representing the blood vessel of the given patient over at least a portion of a cardiac cycle, the set of images having been acquired by a medical imaging apparatus, the blood vessel comprising the aneurysm; segmenting the set of images to obtain at least a segmented outer wall of the aneurysm and a segmented lumen at a plurality of time steps over at least the portion of the cardiac cycle; calculating, based on the segmented outer wall and the segmented lumen over the plurality of time steps, wall volumetric changes and lumen volumetric changes;calculating, based on the lumen volumetric changes and the outer wall volumetric changes, thrombus volumetric changes over the plurality of time steps; classifying, based on at least the lumen volumetric changes and the thrombus volumetric changes, the aneurysm as one of: a first type of aneurysm, a second type of aneurysm, a third type of aneurysm and a fourth type of aneurysm.

13. The system of claim 12, wherein said classifying is further based on the outer wall volumetric changes, the at least one processor being configured for classifying the aneurysm as being one of: the first type of aneurysm in response to the lumen volumetric changes being negative over a majority of the plurality of time steps, the second type of aneurysm in response to: the lumen volumetric changes being within a first threshold range, and the outer wall volumetric changes and the thrombus volumetric changes being within a second threshold range, the third type of aneurysm in response to: the lumen volumetric changes and the thrombus volumetric changes being within a third threshold range; and the fourth type of aneurysm in response to: the lumen volumetric changes being within a fourth threshold range of the outer wall volumetric changes, and the thrombus volumetric changes being negative for at least one of the plurality of time steps.

14. The system of claim 12, wherein the at least one processor is further configured for calculating an average thrombus volumetric change based on the thrombus volumetric changes and an average lumen volumetric change based on the lumen volumetric changes, the at least one processor being configured for classifying, based on the average thrombus volumetric change and the average lumen volumetric change, the aneurysm as one of:the first type of aneurysm when the average thrombus volumetric change is at least equal to the average lumen volumetric change and the average lumen volumetric change is less than a first change threshold; the second type of aneurysm when the average thrombus volumetric change is at least equal to the average lumen volumetric change and the average lumen volumetric change is at least equal to the first change threshold; the third type of aneurysm when the average thrombus volumetric change is less than the average lumen volumetric change and the average thrombus volumetric change is at least equal to a second change threshold; and the fourth type of aneurysm when the average thrombus volumetric change is less than the average lumen volumetric change and the average thrombus volumetric change is less than the second change threshold.

15. The system of claim 14 wherein an initial thrombus volumetric change and an initial lumen volumetric change are each associated with a first one of the plurality of time steps, the at least one processor being further configured for: dividing the average thrombus volumetric change by the initial thrombus volumetric change, thereby obtaining a thrombus volumetric change percentage; and dividing the average lumen volumetric change by the initial lumen volumetric change, thereby obtaining a lumen volumetric change percentage, the at least one processor being configured for classifying, based on the thrombus volumetric change percentage and the lumen volumetric change percentage, the aneurysm as one of: the first type of aneurysm when the thrombus volumetric change percentage is at least equal to the lumen volumetric change percentage and the lumen volumetric change percentage is less than a first percentage threshold;the second type of aneurysm when the thrombus volumetric change percentage is at least equal to the lumen volumetric change percentage and the lumen volumetric change percentage is at least equal to the first percentage threshold; the third type of aneurysm when the thrombus volumetric change percentage is less than the lumen volumetric change percentage and the thrombus volumetric change percentage is at least equal to a second percentage threshold; and the fourth type of aneurysm when the thrombus volumetric change percentage is less than the lumen volumetric change percentage and the thrombus volumetric change percentage is less than the second percentage threshold.

16. The system of any one of claims 12 to 15, wherein the first type of aneurysm is indicative of wall delamination.

17. The system of any one of claims 12 to 16, wherein the fourth type of aneurysm is indicative of an impending rupture of the aneurysm.

18. The system of any one of claims 12 to 17, wherein said calculating, based on the lumen volumetric changes and the outer wall volumetric changes, the thrombus volumetric changes over the plurality of time steps comprises: calculating a difference between the outer wall volumetric changes and the lumen volumetric changes.

19. The system of any one of claims 12 to 18, wherein the at least the first portion comprises a majority of the plurality of time steps.

20. The system of any one of claims 12 to 19, wherein said calculating, based on the segmented outer wall and the segmented lumen over the plurality of time steps, the wall volumetric changes and the lumen volumetric changes comprises: generating, based on the segmented outer wall over the plurality of time steps, outer wall meshes over the plurality of time steps;calculating volumes of the outer wall meshes over the plurality of time steps; determining the wall volumetric changes based on the volumes of the outer wall meshes over the plurality of time steps; generating, based on the segmented lumen over the plurality of time steps, segmented lumen meshes over the plurality of time steps; calculating volumes of the outer wall meshes over the plurality of time steps; and determining the lumen volumetric changes based on the volumes of the lumen meshes over the plurality of time steps.

21. The system of claim 20, wherein said determining the lumen volumetric changes based on the volumes of the lumen meshes over the plurality of time steps and determining the wall volumetric changes based on the volumes of the outer wall meshes over the plurality of time steps comprises determining the lumen volumetric changes based on the volumes of the lumen meshes over the plurality of time steps and determining the wall volumetric changes based on the volumes of the outer wall meshes over ten evenly spaced time steps of the cardiac cycle.

22. The system of claim 21, said determining the lumen volumetric changes based on the volumes of the lumen meshes over the plurality of time steps and determining the wall volumetric changes based on the volumes of the outer wall meshes over the plurality of time steps are relative to a diastolic time of the cardiac cycle.

23. A non-transitory storage medium storing computer-readable instructions thereon, the computer-readable instructions upon being executed by at least one processor, cause the at least one processor to perform the steps of the method of any one of claims 1 to 11.

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