Systems and methods for carbon dioxide angiographic roadmapping imaging

Abstract

The invention is entitled "Systems and methods for carbon dioxide angiographic roadmapping imaging." The present disclosure relates to systems and methods for visualizing a guidewire in a roadmapping image. According to certain embodiments, a method includes generating a background mask from at least one background image, wherein the at least one background image includes a vessel of interest; generating a contrast mask from at least one contrast image, wherein the at least one contrast image includes a contrast agent within the vessel of interest; receiving a guidewire image, wherein the guidewire image includes a guidewire within the vessel of interest; generating a roadmapping image from the background mask, the contrast mask, and the guidewire image, wherein the roadmapping image includes the vessel of interest and the guidewire; and outputting the roadmapping image to a display.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to systems and methods for visualizing a guidewire in a roadmapping image based on digital subtraction angiography, and more particularly to systems and methods for visualizing a guidewire in a roadmapping image based on carbon dioxide digital subtraction angiography. BACKGROUND

[0002] Interventional cardiology involves detection, cleaning, and / or stent implantation of a coronary artery that has become obstructed due to plaque buildup on the walls of the artery. When a coronary artery becomes obstructed, a surgeon can attempt to clear the occlusion and / or stent implantation by performing a retrograde navigation within the artery. Retrograde navigation involves introducing a guidewire into a non-occluded artery and navigating the guidewire antegrade within the non-occluded artery through a collateral artery that connects the non-occluded artery and the occluded artery and into a distal end of the occluded artery in order to access the occlusion from a downstream side. After the guidewire reaches its target, the guidewire is used as a guide for a larger catheter (i.e., a balloon catheter) that is then used to complete the procedure. As the guidewire moves through the body, the guidewire can be visualized using angiography. SUMMARY

[0003] In one embodiment, the present disclosure provides a method. The method includes generating a background mask from at least one background image, wherein the at least one background image includes a blood vessel of interest; generating a contrast mask from at least one contrast image, wherein the at least one contrast image includes a contrast agent within the blood vessel of interest; receiving a guidewire image, wherein the guidewire image includes a guidewire within the blood vessel of interest; generating a roadmapping image from the background mask, the contrast mask, and the guidewire image, wherein the roadmapping image includes the blood vessel of interest and the guidewire; and outputting the roadmapping image to a display.

[0004] In another embodiment, the present disclosure provides a system. The system includes an x-ray imaging device; a processor; and a computer-readable storage medium in communication with the processor. When the processor executes computer-readable instructions stored in the computer-readable storage medium, the instructions cause the processor to: generate a background mask from at least one background image generated by the x-ray imaging device, wherein the at least one background image includes a blood vessel of interest; generate a contrast mask from at least one contrast image generated by the x-ray imaging device, wherein the at least one contrast image includes a contrast agent within the blood vessel of interest; receive a guidewire image generated by the x-ray imaging device, wherein the guidewire image includes a guidewire within the blood vessel of interest; generate a roadmapping image from the background mask, the contrast mask, and the guidewire image, wherein the roadmapping image includes the blood vessel of interest and the guidewire; and output the roadmapping image to a display.

[0005] In another embodiment, the present disclosure provides a computer-readable storage medium having computer-readable instructions. When a processor executes the computer-readable instructions, the instructions cause the processor to: generate a real-time roadmap image from a background mask including a background of a blood vessel of interest, a contrast mask including contrast agent within the blood vessel of interest, and a real-time guidewire image; and output the roadmap image to a display. BRIEF DESCRIPTION OF DRAWINGS

[0006] Various aspects of the disclosure can be better understood after a reading of the following detailed description together with the drawings wherein:

[0007] Figure 1 An imaging system is shown in accordance with example embodiments;

[0008] Figure 2 is a block diagram of an imaging system in accordance with example embodiments; and

[0009] Figure 3 A cloud computing environment is shown in accordance with example embodiments;

[0010] Figure 4 is a flowchart of a method for visualizing a guidewire in a roadmap image in accordance with example embodiments; and

[0011] Figure 5 A roadmap image is shown in accordance with example embodiments.

[0012] These drawings show particular aspects of the components, systems, and methods for visualizing a guidewire in a roadmap image. Together with the following description, the drawings show and illustrate principles of the structures, methods, and concepts described herein. In the drawings, the thickness and size of components can be exaggerated or otherwise modified for clarity. Well-known structures, materials, or operations are not shown or described in detail to avoid obscuring aspects of the components, systems, and methods described. DETAILED DESCRIPTION

[0013] One or more specific embodiments of the present disclosure are described below. These described embodiments are merely examples for visualizing a guidewire in a roadmap image. One skilled in the art will understand that the specific details described in the embodiments can be modified in various ways without departing from the spirit of the present disclosure.

[0014] When introducing elements of various embodiments of the present disclosure, the articles “a,” “an,” and “the” are intended to mean that there are one or more of the elements. The terms “first,” “second,” and the like do not denote any order, quantity, or importance, but are used to distinguish one element from another. The terms “comprises,” “comprising,” “includes,” “including,” and the like are intended to be inclusive and mean that there can be additional elements other than the listed elements. As used herein, the terms “connected to,” “coupled to,” and the like are intended to mean that two objects (i.e., materials, elements, structures, members, etc.) are either directly or indirectly connected or coupled to each other, whether it is directly connected or coupled to each other, or one or more intervening objects are present between the two objects. Also, it is to be understood that a reference to “one embodiment” or “an embodiment” of the present disclosure is not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the referenced features.

[0015] When performing interventional cardiology procedures, it is important to clearly visualize a guide wire as it is moved through the body. As previously mentioned, angiography can be used to visualize a guide wire as it is moved through an artery. During angiography imaging, a contrast agent that is visible upon X-ray irradiation is injected into the patient. The contrast agent helps to contrast the guide wire from the background of the image and / or the artery containing the guide wire.

[0016] Some angiography procedures for guide wire viewing use iodine as a contrast agent and include digitally subtracting a fluoroscopic image from an earlier generated image (or mask) of the same region. In the fluoroscopic image, the guide wire is dark and also appears dark in the previously generated masked blood vessels. After subtraction, the background and bone structure in both the fluoroscopic image and the mask are canceled, and the dark blood vessels are inverted to white. Thus, in the fluoroscopic image depicting the guide wire in the blood vessels, the guide wire appears dark and the blood vessels appear white. The guide wire within the blood vessels can be displayed to a surgeon performing an interventional cardiology procedure in the form of a road map image. As used herein, a road map image includes a real-time fluoroscopic image superimposed on or otherwise combined with a previously generated digitally subtracted angiogram. Thus, an iodinated digital subtraction angiography-based road map image (“iodinated angiography road map” based on “iodinated DSA”) clearly displays the guide wire and the blood vessels as a guide wire and angiogram.

[0017] Unfortunately, iodine is not a contrast agent for all patients. For example, iodine cannot be used for patients with kidney failure or who are hypersensitive to iodine. In such cases, carbon dioxide (C02) can alternatively be used as a contrast agent. When C02is injected into a blood vessel, the C02replaces the blood, which results in lower X-ray attenuation. Unfortunately, current roadmap images with C02as the contrast agent are generated using the same protocol as iodinated contrast agents, so the C02roadmap images are not optimal because both the blood vessels and the guidewire appear dark or white, making it difficult to observe the guidewire. Thus, there is a need for a method and / or system for generating C02angiographic roadmaps in which the guidewire and blood vessels contrast with each other.

[0018] With general reference to the figures, the present disclosure describes systems and methods for visualizing a guidewire in C02angiographic roadmap images. While the embodiments herein are described with respect to an x-ray fluoroscopic imaging system (i.e., an x-ray angiographic imaging system as shown in Figure 1 It should be understood that other embodiments can include other devices such as computed tomography ("CT") imaging systems, positron emission tomography ("PET") systems, real-time endoscopic imaging systems, and / or any other type of imaging system that utilizes a contrast agent. It should also be understood that the embodiments described herein can be used to analyze objects within any material that can be imaged internally. As such, the embodiments disclosed herein are not limited to analyzing objects within human tissue.

[0019] While the embodiments disclosed herein are described with respect to an x-ray based fluoroscopic imaging system (as shown in Figure 1 It should be understood that other embodiments can include other devices such as computed tomography ("CT") imaging systems, positron emission tomography ("PET") systems, real-time endoscopic imaging systems, and / or any other type of imaging system that utilizes a contrast agent. It should also be understood that the embodiments described herein can be used to analyze objects within any material that can be imaged internally. As such, the embodiments disclosed herein are not limited to analyzing objects within human tissue.

[0020] Referring now to Figure 1 , an imaging system 100 according to an example embodiment is shown. In one embodiment, the imaging system 100 is an x-ray angiographic imaging system. While Figure 1A fixed c-arm imaging system 100 is shown, but in a second embodiment, the imaging system 100 can be a mobile c-arm imaging system. In another embodiment, the imaging system 100 can be a non-c-arm imaging system. The system 100 is operated to image one or more structures (i.e., internal organs, blood vessels, etc.) within a patient 102. For example, the patient 102 can have one or more blocked coronary arteries, and the imaging structure can be the one or more blocked coronary arteries. As shown, in some embodiments, the imaging system 100 includes a patient support 104 adapted to support the patient 102 while the patient 102 is being imaged, a radiation source 106, and a radiation sensitive detector 108. The radiation patient support 104, the radiation source 106, and the radiation sensitive detector array 108 collectively make up an imaging device 110. In one embodiment, the imaging device 110 is an x-ray angiography imaging device. Figure 1

[0021] The imaging system 100 also includes a computing device 112 and a display 114. As used herein, a computing device is any device / system capable of processing and transmitting data (i.e., tablet computer, handheld computing device, smart phone, personal computer, laptop computer, network computer, server, mobile communication device, etc.). While the computing device 112 and the display 114 are depicted as being separate from the imaging device 110, in some embodiments, the imaging device 110 can include the computing device 112 and the display 114.

[0022] The computing device 112 is connected to and in communication with the imaging device 110 and the display 114 via a wired or wireless connection, allowing the computing device 112 to transmit data to or receive data from the imaging device 110 and output images and / or video to the display 114. The imaging device 110 and the computing device 112 can be connected to a network (i.e., wide area network (WAN), local area network (LAN), public network (Internet), etc.) that allows the imaging device 110 and the computing device 112 to communicate with each other when connected to the same network. In some embodiments, the network can be considered a private network connection and can include, for example, a virtual private network or encryption or other security mechanisms employed over the public Internet. In one embodiment, the computing device 112 can be remotely located relative to the imaging device 110. In another embodiment, the computing device 112 can be located in the same room as the imaging device 110.

[0023] ​The computing device 112 includes a processor 116 and a system memory 118. The processor 116 is in communication with the system memory 118 and can execute computer-readable program instructions stored in the system memory 118. In one embodiment, the processor can include a central processing unit (CPU). In another embodiment, the processor can include other electronic components capable of executing computer-readable program instructions such as a digital signal processor, a field programmable gate array (FPGA), or a graphics board. In another embodiment, the processor can be configured as a graphics processing unit (GPU) having parallel processing capabilities. In another embodiment, the processor can include multiple electronic components capable of executing computer-readable instructions. For example, the processor can include two or more electronic components selected from the list of electronic components including: a CPU, a digital signal processor, an FPGA, and a GPU.

[0024] The system memory 118 is a computer-readable storage medium. As used herein, a computer-readable storage medium is any device that stores computer-readable program instructions for execution by the processor and is not interpreted as transitory. Computer-readable program instructions include programs, logic, data structures, modules, architectures, etc. that, when stored in a computer-readable storage medium and executed by the processor, create means for implementing functions / acts. When stored in a computer-readable storage medium and executed by the processor, computer-readable program instructions instruct the computer system and / or another device to act in a particular manner, such that the computer-readable storage medium includes an article of manufacture. System memory, as used herein, includes volatile memory (i.e., random access memory (RAM) and dynamic RAM (DRAM)) and non-volatile memory (i.e., flash memory, read only memory (ROM), magnetic computer storage devices, etc.). In some embodiments, the system memory can also include a cache.

[0025] The display 114 displays a graphical user interface (GUI). As used herein, a GUI includes editable data (i.e., patient data) and / or selectable icons. A user can use an external device (i.e., a keyboard, a mouse, a touchscreen, etc.) connected to the computing device 112 to select icons and / or edit data. Selecting an icon / inputting information causes the processor to execute computer-readable program instructions stored in a computer-readable storage medium, which causes the processor to perform various tasks. For example, a user can use an external device to select an icon that causes the processor 116 to control the medical imaging device 110 to perform an imaging session. As used herein, an imaging session includes acquiring / generating a plurality of medical images, including an angiogram image of a blood vessel of interest.

[0026] Referring now to Figure 2 , a block diagram of an imaging system 100 is shown, in accordance with an example embodiment.

[0027] When the processor 116 executes the computer-readable program instructions to begin a medical imaging procedure, the processor 116 sends a signal to the radiation source 106 to emit radiation. In some embodiments, the radiation source 106 is an X-ray tube. In response, the radiation source 106 emits radiation 202 that traverses the examination region 204. The radiation-sensitive detector 108 detects the radiation 202 that has traversed the examination region 204 and has been attenuated by the patient 102. In response to detecting the radiation 202, the radiation-sensitive detector generates projection data. The intensity of the detected radiation is dependent on the attenuation of the patient 102. The radiation-sensitive detector 108 includes elements that each produce a separate electrical signal that is a measure of the attenuation at the element’s location. The attenuation measurements from all of the detector elements are individually acquired to produce a transmission profile.

[0028] The imaging device 110 sends the projection data to the computing device 112. In response to receiving the projection data, the processor 116 can execute computer-readable program instructions stored in the system memory 118 to process the projection data to reconstruct an image and / or video. As used herein, the phrase “reconstruct an image” is not intended to exclude embodiments of the present application in which data representative of an image is generated rather than a visual image. Thus, as used herein, the term “image” refers broadly to both visual images and data representative of visual images. Once reconstruction is complete, the processor 116 can output the reconstructed image / video to the display 114 in the form of image data.

[0029] In one embodiment, in which the processor 116 outputs a video to the display 114, the video can include a plurality of composite images / frames. As used herein, the term “composite image” means an image that is generated from two or more other images. For example, in embodiments, a single composite image can be generated by registering one or more real-time images to a previously acquired mask. In some embodiments, the video feed output to the display 114 can be a live / real-time and / or near real-time feed.

[0030] In one embodiment, the medical imaging procedure is an angiographic imaging procedure of a blood vessel of interest. The angiographic imaging procedure includes injecting a contrast agent (i.e., CO2) into the blood vessel of interest or into a blood vessel upstream of the blood vessel of interest. During the angiographic imaging procedure, the imaging device (i.e., the imaging device 110) continuously captures projection data, and the processor (i.e., the processor 116) outputs reconstructed images (based on the projection data) to the display (i.e., the display 114) in real-time.

[0031] The contrast agent causes the lumen of the vessel of interest to have a different attenuation value than the region surrounding the vessel of interest (i.e., the background of the vessel of interest). For example, when the contrast agent is CO2 or another contrast agent that displaces blood within the vessel of interest, the contrast agent causes the lumen of the vessel of interest to have a lower attenuation value than the background of the vessel of interest. Because the vessel with the contrast agent has a different attenuation value than the background, the processor can output images to a display in which the vessel of interest is visible. In other words, during an angiographic imaging procedure, the processor outputs real-time video of the vessel of interest based on the projection data captured by the imaging device in which the vessel of interest is visible. In other words, during an angiographic imaging procedure, the processor outputs real-time fluoroscopic images of the vessel of interest based on the projection data captured by the imaging device in which the vessel of interest is visible.

[0032] In one embodiment, in which the imaging procedure is an angiographic imaging procedure of a vessel of interest, the angiographic imaging procedure can be performed during an interventional procedure that includes inserting a guidewire into the vessel of interest. The guidewire can have a different attenuation value than the vessel with the contrast agent and / or the background of the vessel of interest. In this embodiment, during the angiographic imaging procedure, the processor can output images / real-time video / real-time fluoroscopic images in which the vessel of interest and the guidewire are visible.

[0033] In another embodiment, in which the imaging procedure is an angiographic imaging procedure of a vessel of interest performed during an interventional procedure that includes inserting a guidewire into the vessel of interest, the imaging device can capture projection data of the vessel of interest prior to the angiographic imaging procedure. The processor can reconstruct the previously captured image data to form a mask image of the vessel of interest. During the angiographic imaging procedure performed when the guidewire is in the vessel of interest, the processor can reconstruct images from the projection data captured during the angiographic imaging procedure and subtract the mask from the images generated during the angiographic imaging procedure to form a roadmap image. The processor can output the roadmap image to a display as a plurality of images or real-time video.

[0034] Referring now to Figure 3 , a cloud computing environment 300 according to an example embodiment is shown. As Figure 3 shown, in some embodiments, the cloud computing environment 300 includes one or more nodes 302. Each node 302 can include a computer system / server (i.e., a personal computer system, a server computer system, a mainframe computer system, etc.). The nodes 302 can communicate with each other and can be grouped into one or more networks. Each node 302 can include a computer-readable storage medium and a processor that executes instructions in the computer-readable storage medium. As Figure 3As further shown, one or more devices (or systems) 304 can be connected to the cloud computing environment 300. The one or more devices 304 can be connected to the same or different network (i.e., LAN, WAN, public network, etc.). The one or more nodes 302 can communicate with the devices 304, thereby allowing the nodes 302 to provide software services to the devices 304. In one embodiment, the nodes 302 can comprise the computing device 112. In another embodiment, the devices 304 can comprise the computing device 112.

[0035] Referring now to Figure 4 , a flowchart of a method 400 for visualizing a guidewire in an angiographic roadmap is shown, in accordance with example embodiments. Figure 4 Aspects of the method 400 shown can be performed by a“configured processor.” As used herein, a configured processor is a processor configured according to an aspect of the present disclosure. The configured processor can be the processor 116, a processor of the node 302, or a processor of the device 304. The configured processor executes various computer-readable program instructions to perform the steps of the method 400. The computer-readable program instructions that, when executed by the configured processor, cause the configured processor to perform the steps of the method 400 are stored in a computer-readable storage medium, including but not limited to the system memory 118, a system memory of the node 302, or a system memory of the device 304. When executed by the configured processor, the steps of the method 400 cause the configured processor to output an angiographic roadmap image in which blood vessels are contrasted relative to a guidewire within the blood vessels. While the method 400 implements CO2 as a contrast agent to generate the roadmap, it should be understood that other negative contrast agents (i.e., oxygen, etc.) can also be used to generate the roadmap.

[0036] At 402, the configured processor receives a sequence of background images {I Background (l), l = 1, 2,..., L}. In some embodiments, the background images are generated by the imaging system 100. The background images include bone structures, tissue structures, and blood-filled vessels of interest. The imaging system 100 generates the background images during an imaging session in which there is no contrast agent (i.e., CO2 contrast agent) or guidewire present in the vessels of interest. For example, during the imaging session, the imaging system 100 can generate sixteen images of the vessels of interest of the patient 102 during the imaging session that do not include the CO2 contrast agent or guidewire. Thus, in this example, {I Background (l), l = 1-16}.

[0037] At 404, the configured processor generates a background mask image (M Background ). The configured processor generates M BackgroundThese image data are acquired without contrast agent injection or without any subject in the blood vessels. As such, the configured processor can generate M Background :

[0038]

[0039] At 406, the configured processor receives a sequence of CO2 injection images {I CO2 (k), k = 1, 2,..., K}. Since the x-ray attenuation of CO2 is less than the x-ray attenuation of blood, these CO2 injection images can be considered as if the blood vessels are empty. In one example, the configured processor receives 120 contrast agent injection images. Thus, in this example, {I CO2 (k), k = 1-120}. In one embodiment, the sequence of CO2 injection images and the sequence of background images are generated by the imaging system 100 during the same imaging session. In another embodiment, the imaging system 100 generates the sequence of CO2 injection images and the sequence of background images during different imaging sessions. The sequence of CO2 injection images includes the blood vessels of interest by peak opacification of CO2 within the blood vessels of interest. In some embodiments, in the first image in the sequence of CO2 injection images, the blood vessels of interest do not include any infused CO2 within the blood vessels of interest. That is, the first image can be acquired before the infused CO2 reaches the blood vessels of interest.

[0040] At 408, the configured processor generates a CO2 mask image (M CO2 ) from the CO2 injection images. The configured processor generates M CO2 :

[0041] M CO2 = CO2_Peak_Opacification [I CO2 (k), k = 1, 2,..., K]

[0042] where CO2 peak opacification is an operation that finds the most positive pixel value for each pixel location over the K CO2 injection images {I CO2 (k), k = 1, 2,..., K}.

[0043] At 410, the configured processor receives a sequence of real-time guidewire images {F GWire(n), n = 1, 2, ..., N} (or "a set of guidewire images"). The guidewire images include the guidewire within the vessel of interest. In one embodiment, this set of guidewire images is generated by imaging system 100. In this embodiment, imaging system 100 generates guidewire images as the guidewire moves through the vessel of interest. In one example, a configured processor receives three hundred guidewire images. That is, imaging device 110 generates three hundred guidewire images during an imaging session. Therefore, in this example, {F GWire (n), n = 1-300}. In some implementations, the Nth guidewire image is the last image acquired / reconstructed during the angiography imaging procedure. In this implementation, {F GWire The sequence {(n), n = 1, 2, ..., N} corresponds to a set of guidewire images acquired during an angiography imaging procedure. Furthermore, the number of guidewire images in this set can increase as the imaging procedure progresses. That is, the Nth image may correspond to the most recently generated real-time image by the imaging system.

[0044] At position 412, the configured processor will M Background and M CO2 Registration and, based on registration, from M in the linear domain according to Formula 3. CO2 Subtract M from the middle Background :

[0045] [ln(M CO2 )-ln(M Background )]

[0046] The logarithmic operation ln(·) converts the pixel values ​​of the image into a linear domain for subtraction. Since M... CO2 It includes empty blood vessels as well as tissue and bone structures, while M Background It includes blood vessels filled with blood, as well as anatomical structures such as tissues and bones; therefore, [ln(M CO2 )-ln(M Background Background (e.g., tissue and bone structures, and blood-filled vessels) is removed and an image containing only the vessels of interest is generated. In one embodiment, the vessels of interest are located in M... CO2 The center is white. In this implementation, [ln(M CO2 )-ln(M Background [] Only white vessels of interest are included.

[0047] At 414, the configured processor will M Background And the guidewire image F in this set of guidewire images GWire(n) Registration and, based on registration, from F in the linear domain according to Formula 4. GWire(n) Subtract M Background :

[0048] [ln(F GWire (n))-ln(M Background )].

[0049] Since F GWire (n) includes the guidewire as well as background, and M Background includes only background, [ln(F GWire (n))-ln(M Background )] removes the background and generates an image that includes only the guidewire. In one embodiment, the guidewire is dark (i.e., dark gray, black, etc.). In this embodiment, [ln(F GWire (n))-ln(M Background )] includes only dark guidewires.

[0050] At 416, the configured processor generates a roadmap image (i.e., a CO2 roadmap image). The configured processor generates the roadmap image by registering the image generated at 412 (the image including only the blood vessel of interest) and the image generated at 414 (the image including only the guidewire) and superimposing (or otherwise combining) the image generated at 412 onto the image generated at 414 according to the registration. In this way, the roadmap image includes the blood vessel of interest and the guidewire.

[0051] In one embodiment, the configured processor can apply a weighting factor, a, to the images generated at 412 and 414 in order to balance the contrast between the blood vessel and the guidewire in the roadmap image. The weighting factor can be determined as a function of at least one patient parameter (i.e., patient thickness, patient weight, etc.) and is greater than 0 and less than 1 (0 < a < 1). Thus, in this embodiment, the configured processor generates the roadmap image according to equation 5:

[0052] R MAP(n) = (1 - a) [ln(F GWire (n))-ln(M Background )] + a [ln(M CO2 )-ln(M Background )]

[0053] where R MAP (n) is the CO2 roadmap image for image n in the set of guidewire images. In one embodiment, the weighting factor increases with patient thickness or patient weight. For example, a first patient can be larger than a second patient (i.e., have a thicker abdominal cross-section). In this example, a first weighting factor corresponding to the first patient is greater than a second weighting factor corresponding to the second patient.

[0054] While equations 3-5 include performing F GWire (n), M Background , and M CO2logarithmic linearization, but Equation 3-5 can linearize F by applying other functions (i.e., a polynomial function, a linear-log function in which a linear function is used for smaller signals and a logarithmic function is used for larger signals, etc.) to F GWire (n), M Background and M CO2 linearize F GWire(n) , M Background and M CO2 .

[0055] Turning temporarily to Figure 5 , a roadmap image 500 is shown in accordance with example embodiments. In one embodiment, the roadmap image 500 is generated at 416 and includes a blood vessel of interest 502 and a guidewire 504. Since, in some embodiments, [ln(M CO2 (n)) - ln(M Background )] contains only the white blood vessel of interest and [ln(F GWire (n)) - ln(M Background )] contains only the dark guidewire, the blood vessel of interest 502 can be white and the guidewire 504 can be dark. Due to this contrast, the method 400 can generate a roadmap image (i.e., a CO2 roadmap image) in which the guidewire is more visible.

[0056] Returning to Figure 4 , at 418, the configured processor outputs the CO2 roadmap image to a display.

[0057] At 420, the configured processor determines whether n = N on F GWire (n). In other words, at 420, the configured processor determines whether the nthimage used to generate F MAP (n) is the last image in the set of guidewire images. As previously mentioned, in some embodiments, F GWire (n) corresponds to a real-time image, and thus, F GWire (n) can correspond to the last image in the imaging procedure.

[0058] In response to determining that F GWire (n), n ≠ N, the configured processor repeats steps 414-418 for F GWire (n+1).

[0059] At 422, in response to determining that F GWire (n), n = N, the configured processor ends the method 400. Although Figure 4 the method 400 is depicted as proceeding in an orderly operation, any step of the method 400 can occur simultaneously. For example, the configured processor can perform steps 414-418 simultaneously. Additionally, the configured processor can acquire FGWire (n) immediately after outputting R MAP (N), such that the configured processor outputs R MAP (N) as a real-time image. Further, the configured processor can output a first roadmap image (i.e., R MAP (N)), and immediately after outputting a second roadmap image (i.e., R MAP (n+1)), such that the configured processor outputs roadmap images as a video.

[0060] In addition to any prior indicated modifications, many other variations and alterations in the arrangements will occur to those skilled in the art without departing from the spirit and scope of this description, and it is intended that the appended claims cover all such modifications and arrangements. Accordingly, although specific and detailed descriptions of information have been given above in connection with currently preferred and alternative aspects, it will be appreciated that numerous modifications can be made without departing from the principles and concepts set forth herein, including but not limited to form, function, manner of operation, and use. Also, as used herein, examples and embodiments are intended to be illustrative only, and are not to be construed as limiting in any way.

Claims

1. A method for angiographic roadmapping imaging, comprising: generating a background mask from at least one background image, wherein the at least one background image includes a vessel of interest; generating a contrast mask from at least one contrast image, wherein the at least one contrast image includes a contrast agent within the vessel of interest; receiving a guidewire image, wherein the guidewire image includes a guidewire within the vessel of interest; generating a roadmapping image from the background mask, the contrast mask, the guidewire image, and a weighting factor, wherein the weighting factor is determined from a patient parameter, and wherein the roadmapping image includes the vessel of interest and the guidewire; and outputting the roadmapping image to a display.

2. The method of claim 1, further comprising: imageing the background mask, the contrast mask, and the guidewire image; and generating the roadmapping image from a linearized background mask, a linearized contrast mask, and a linearized guidewire image.

3. The method of claim 2, wherein the linearization is a logarithmic operation.

4. The method of claim 1, wherein the roadmapping image is a real-time image.

5. The method of claim 1, wherein the guidewire and the vessel of interest are contrasted with each other in the roadmapping image.

6. The method of claim 1, wherein the contrast agent is carbon dioxide.

7. The method of claim 1, wherein the guidewire image is a real-time image.

8. The method of claim 1, wherein an x-ray angiographic imaging device generates the at least one background image, the at least one contrast image, and the guidewire image.

9. The method of claim 8, wherein the x-ray angiographic imaging device generates a plurality of background images and a plurality of contrast images that include the vessel of interest, and wherein the plurality of background images include neither the guidewire nor the contrast agent.

10. The method of claim 2, wherein generating the roadmapping image comprises: subtracting the linearized background mask from the linearized contrast mask; and subtracting the linearized background mask from the linearized guidewire image.

11. A system for angiographic roadmapping imaging, comprising: an x-ray imaging device; a processor; and a computer readable storage medium in communication with the processor, wherein the processor executes computer readable instructions stored in the computer readable storage medium that cause the processor to: generate a background mask from at least one background image generated by the x-ray imaging device, wherein the at least one background image is acquired without a contrast agent injection and without a guidewire within the vessel; generate a contrast mask from at least one contrast image generated by the x-ray imaging device, wherein the at least one contrast image includes a contrast agent within a vessel of interest; receive a guidewire image generated by the x-ray imaging device, wherein the guidewire image includes a guidewire within the vessel of interest; generating a roadmap image from the background mask, the contrast mask, the guidewire image, and a weighting factor, wherein the weighting factor is determined from a patient parameter, and wherein the roadmap image includes the vessel of interest and the guidewire; and outputting the roadmap image to a display.

12. The system of claim 11, wherein the instructions further cause the processor to: linearize the background mask, the contrast mask, and the guidewire image; and generate the roadmap image from the linearized background mask, the linearized contrast mask, and the linearized guidewire image.

13. The system of claim 11, wherein the guidewire image and the roadmap image are real-time images.

14. A computer-readable storage medium having computer-readable instructions that, when executed by a processor, cause the processor to perform the method of any one of claims 1-10.

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