# US 2021/0279861 A1 · A method of processing images > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0279861 A1 - Document ID: US20210279861A1 - Status: Published application - Kind: A1 - Application number: 16/347,544 - Filed: 2017-11-02 - Published: 2021-09-09 - Earliest claimed: 2016-11-04 - Assignees: University College Dublin, National University of Ireland, Dublin - Applicants: University College Dublin, National University of Ireland, Dublin - Inventors: Peter Joseph MACMAHON - Web page: https://patentgrep.com/patent/US20210279861A1 ## CPC - G06T 7/0012: {Biomedical image inspection} - G06T 7/0016: {involving temporal comparison} - A61B 5/02007: {Evaluating blood vessel condition, e.g. elasticity, compliance} - A61B 5/4064: {Evaluating the brain (for intracranial pressure A61B5/031; for cerebral blood gases A61B5/14553; using EEG A61B5/369)} - A61B 6/481: {involving the use of contrast agents} - A61B 6/504: {for diagnosis of blood vessels, e.g. by angiography} - G06T 5/50: using two or more images, e.g. averaging or subtraction - A61B 6/032: {Transmission computed tomography [CT]} - A61B 2576/026: for the brain - G06T 2207/10081: Computed x-ray tomography [CT] - G06T 2207/20224: Image subtraction - G06T 2207/30016: Brain - G06T 2207/30101: Blood vessel; Artery; Vein; Vascular - G06T 2207/30104: Vascular flow; Blood flow; Perfusion - G16H 30/40: for processing medical images, e.g. editing - G06T: IMAGE DATA PROCESSING OR GENERATION, IN GENERAL - A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D) - G16H: HEALTHCARE INFORMATICS, i.e. INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR THE HANDLING OR PROCESSING OF MEDICAL OR HEALTHCARE DATA ## Abstract A method of processing cross-sectional post contrast images. The method comprises obtaining a first cross-sectional post contrast image of at least part of a body (70). The first cross-sectional post contrast image represents a first time point. A second cross-sectional post contrast image of the at least part of the body is also obtained (72). The second cross-sectional post contrast image represents a second time point which is different from the first time point. A first difference image is generated using the first and second cross-sectional post contrast images (74). The first difference image highlights any differences between the first and second cross-sectional post contrast images. ## Claims ### Claim 1 A method of processing cross-sectional post contrast images, the method comprising: obtaining a first cross-sectional post contrast image of at least part of a body, the first cross-sectional post contrast image representing a first time point; obtaining a second cross-sectional post contrast image of the at least part of the body, the second cross-sectional post contrast image representing a second time point, the second time point being different from the first time point; and generating a first difference image using the first and second cross-sectional post contrast images, the first difference image highlighting any differences between the first and second cross-sectional post contrast images. ### Claim 2 (depends on 1) A method as claimed in claim 1, wherein generating the first difference image comprises performing a subtraction operation on the first and second cross-sectional post contrast images, the subtraction operation comprising subtracting the first cross-sectional post contrast image from the second cross-sectional post contrast image. ### Claim 3 (depends on 1) A method as claimed in claim 1, wherein the second time point is after the first time point. ### Claim 4 (depends on 1) A method as claimed in claim 1, wherein the second time point is selected based on the expected time required for a difference in contrast opacification to develop in the body after the first time point. ### Claim 5 (depends on 1) A method as claimed in claim 1, wherein the first and second cross-sectional post contrast images are computed tomography (CT) post contrast images. ### Claim 6 (depends on 1) A method as claimed in claim 1, wherein the body is a patient potentially suffering from one or more vessel occlusions in a part of their body, the first and second cross-sectional post contrast images being of the part of the body, the first difference image highlighting the presence or absence of any occluded vessels in the part of the body. ### Claim 7 (depends on 6) A method as claimed in claim 6, wherein the patient is potentially suffering from an acute ischaemic stroke, the first and second cross-sectional post contrast images being of a section of the brain of the patient, the first difference image highlighting the presence or absence of any occluded vessels in the section of the brain. ### Claim 8 (depends on 1) A method as claimed in claim 1, further comprising aligning the first cross-sectional post contrast image with the second cross-sectional post contrast image. ### Claim 9 (depends on 1) A method as claimed in claim 1, further comprising obtaining a third cross-sectional post contrast image of the at least part of the body, the third cross-sectional post contrast image representing a third time point, the third time point being different from the first and second time points. ### Claim 10 (depends on 9) A method as claimed in claim 9, wherein the third time point is after the first and second time points. ### Claim 11 (depends on 9) A method as claimed in claim 9, further comprising generating a second difference using the first and third cross-sectional post contrast images, the second difference image highlighting any differences between the first and third cross-sectional post contrast images. ### Claim 12 (depends on 11) A method as claimed in claim 11, further comprising generating an addition image using the first and second difference images, generating the addition image comprises adding the first difference image to the second difference image. ### Claim 13 An image-processing system comprising a computing device having at least one processor, the image processing system being configured to: obtain a first cross-sectional post contrast image of at least part of a body, the first cross-sectional post contrast image representing a first time point; obtain a second cross-sectional post contrast image of the at least part of the body, the second cross-sectional post contrast image representing a second time point, the second time point being different from the first time point; and generate a first difference image using the first and second cross-sectional post contrast images, the first difference image highlighting any differences between the first and second cross-sectional post contrast images. ### Claim 14 (depends on 13) An image processing system as claimed in claim 13, further comprising an imaging device operatively connected to the computing device. ### Claim 15 A computer-readable medium having computer executable code for obtaining a first cross-sectional post contrast image of at least part of a body, the first cross-sectional post contrast image representing a first time point; obtaining a second cross-sectional post contrast image of the at least part of the body, the second cross-sectional post contrast image representing a second time point, the second time point being different from the first time point; and generating a first difference image using the first and second cross-sectional post contrast images, the first difference image highlighting any differences between the first and second cross-sectional post contrast images. ### Claim 16 (canceled)