# US 9,517,042 B2 · Systems and methods for imaging phase selection for computed tomography imaging > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,517,042 B2 - Document ID: US9517042B2 - Status: Granted - Kind: B2 - Application number: 14/484,544 - Filed: 2014-09-12 - Published: 2016-03-17 - Granted: 2016-12-13 - Earliest claimed: 2014-09-12 - Assignees: General Electric Company - Applicants: General Electric Company - Inventors: Jiang Hsieh; Saad Ahmed Sirohey; Roy A. Nilsen; Suresh Narayanan Narayanan; Guangzhi Cao - Web page: https://patentgrep.com/patent/US9517042B2 ## CPC - A61B 6/032: {Transmission computed tomography [CT]} - A61B 6/06: Diaphragms - A61B 6/481: {involving the use of contrast agents} - A61B 6/486: {involving generating temporal series of image data} - A61B 6/488: {involving pre-scan acquisition} - A61B 6/504: {for diagnosis of blood vessels, e.g. by angiography} - A61B 6/507: {for determination of haemodynamic parameters, e.g. perfusion CT} - A61B 6/5205: {involving processing of raw data to produce diagnostic data} - A61B 6/5217: {extracting a diagnostic or physiological parameter from medical diagnostic data} - A61B 6/5252: {removing objects from field of view, e.g. removing patient table from a CT image} - A61B 6/541: {involving acquisition triggered by a physiological signal} - A61B 6/542: {involving control of exposure} - A61B 6/545: {involving automatic set-up of acquisition parameters} - G06F 18/22: Matching criteria, e.g. proximity measures - G06T 7/0014: {using an image reference approach} - G06T 7/20: Analysis of motion (motion estimation for coding, decoding, compressing or decompressing digital video signals H04N19/43, H04N19/51) - G16H 50/30: for calculating health indices; for individual health risk assessment - A61B 6/025: {Tomosynthesis} - G06T 2207/30048: Heart; Cardiac - A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D) - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) - G06T: IMAGE DATA PROCESSING OR GENERATION, IN GENERAL - G16H: HEALTHCARE INFORMATICS, i.e. INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR THE HANDLING OR PROCESSING OF MEDICAL OR HEALTHCARE DATA ## Abstract An imaging system includes a computed tomography (CT) acquisition unit and a processing unit. The CT acquisition unit includes an X-ray source and a CT detector configured to collect CT imaging data of an object to be imaged. The processing unit includes at least one processor operably coupled to the CT acquisition unit. The processing unit is configured to control the CT acquisition unit to collect at least one sample projection during rotation of the CT acquisition unit about the object to be imaged, compare an intensity of the at least one sample projection to an intensity of a reference projection, select a time to perform an imaging scan based on the comparison of the intensity of the at least one sample projection to the intensity of the reference projection, and control the CT acquisition unit to perform the imaging scan. ## Claims ### Claim 1 An imaging system comprising: a computed tomography (CT) acquisition unit comprising an X-ray source and a CT detector configured to collect CT imaging data of an object to be imaged, the X-ray source and the CT detector configured to be rotated about the object to be imaged and to collect a series of projections of the object as the X-ray source and the CT detector rotate about the object to be imaged; and a processing unit comprising at least one processor operably coupled to the CT acquisition unit, the processing unit configured to: control the CT acquisition unit to collect, at a reference view angle, a reference projection; control the CT acquisition unit to collect at least one sample projection during rotation of the CT acquisition unit about the object to be imaged, compare an intensity of the at least one sample projection to an intensity of the reference projection, wherein the intensity of the at least one sample projection and the intensity of the reference projection are measured intensities, select a time to perform an imaging scan based on the comparison of the intensity of the at least one sample projection to the intensity of the reference projection, and control the CT acquisition unit to perform the imaging scan. ### Claim 2 (depends on 1) The imaging system of claim 1, wherein the processing unit is further configured to remove information corresponding to high density structures from the reference projection and the at least one sample projection before comparing the intensity of the at least one sample projection and the reference projection. ### Claim 3 (depends on 1) The imaging system of claim 1, wherein the processing unit is configured to collect plural candidate projections during each rotation of the CT acquisition unit and to select the at least one sample projection from the plural candidate projections based on a similarity of an angle at which the at least one sample projection was obtained to the reference view angle at which the reference projection was obtained. ### Claim 4 (depends on 1) The imaging system of claim 1, wherein the processing unit is configured to control the CT acquisition unit to perform the imaging scan at a time corresponding to an arterial phase of a perfusion study, wherein the time is selected to correspond to a threshold corresponding to a maximum intensity, and to perform an additional imaging scan at a time corresponding to a venous phase of a perfusion study, wherein the time to perform the additional imaging scan is selected to correspond to a threshold corresponding to a minimum intensity. ### Claim 5 (depends on 1) The imaging system of claim 1, wherein the processing unit is configured to control the CT acquisition unit to collect plural sample projections at different times and to determine a cardiac output based on intensities of the plural sample projections preceding an arterial phase of a perfusion study. ### Claim 6 (depends on 1) The imaging system of claim 1, further comprising a collimator configured to be interposed between the X-ray source and the object to be imaged, the collimator configured to provide wide collimation, wherein the at least one sample projection is taken along a longitudinal view of the object. ### Claim 7 (depends on 6) The imaging system of claim 6, wherein the processing unit is configured to control the CT acquisition unit to collect plural sample projections at different times and to determine a contrast flow rate using the plural sample projections acquired at different times. ### Claim 8 (depends on 7) The imaging system of claim 7, wherein the processing unit is further configured to adjust at least one of pitch, rotation time, or table speed based on the contrast flow rate determined using the plural sample projections. ### Claim 9 (depends on 1) The imaging system of claim 1, wherein the processing unit is further configured to obtain the reference projection and the at least one sample projection with the reference projection and at least one sample projection not including enough information to provide a diagnostically useful image. ### Claim 10 A method comprising: obtaining, with a CT acquisition unit, a reference projection at a reference view angle; obtaining, with the CT acquisition unit, at least one sample projection of CT imaging information during rotation of the CT acquisition unit about an object to be imaged; comparing an intensity of the at least one sample projection to an intensity of the reference projection, wherein the intensity of the at least one sample projection and the intensity of the reference projection are measured intensities; selecting a time to perform an imaging scan based on the comparing of the intensity of the at least one sample projection to the intensity of the reference projection; and controlling the CT acquisition unit to perform the imaging scan based on the selected time. ### Claim 11 (depends on 10) The method of claim 10, wherein obtaining at least one sample projection of CT imaging information during rotation of the CT acquisition unit about an object to be imaged further comprising: collecting plural candidate projections during a rotation of the CT acquisition unit; and selecting the at least one sample projection from the plural candidate projections based on a similarity of an angle at which the at least one sample projection was obtained to the reference view angle at which the reference projection was obtained. ### Claim 12 (depends on 10) The method of claim 10, wherein the object is a human patient, wherein controlling the CT acquisition unit to perform the imaging scan based on the selected time comprises performing the imaging scan on a head of the human patient, and wherein obtaining at least one sample projection of CT imaging information during rotation of the CT acquisition unit comprises obtaining the at least one sample projection from a view oriented laterally of the human patient. ### Claim 13 (depends on 10) The method of claim 10, wherein the object is a human patient, wherein controlling the CT acquisition unit to perform the imaging scan based on the selected time comprises performing the imaging scan on a torso of the human patient and wherein obtaining at least one sample projection of CT imaging information during rotation of the CT acquisition unit comprises obtaining the at least one sample projection from a view oriented at least one of anteriorly or posteriorly of the human patient. ### Claim 14 (depends on 10) The method of claim 10, wherein obtaining at least one sample projection of CT imaging information during rotation if the CT acquisition unit about an object to be imaged comprises: obtaining plural sample projections, and determining corresponding intensities of the plural sample projections, and determining a cardiac output based on the corresponding intensities. ### Claim 15 (depends on 10) The method of claim 10, wherein obtaining at least one sample projection of CT imaging information during rotation of the CT acquisition unit about an object to be imaged comprises obtaining the at least one sample projection along a longitudinal view of the object. ### Claim 16 (depends on 15) The method of claim 15, wherein obtaining at least one sample projection of CT imaging information during rotation of the CT acquisition unit about an object to be imaged comprises obtaining plural sample projections at different times, further comprising determining a contrast flow rate using the plural sample projections acquired at different times. ### Claim 17 (depends on 16) The method of claim 16, further comprising adjusting at least one of pitch, rotation time, or table speed based on the contrast flow rate determined using the plural sample projections. ### Claim 18 A tangible and non-transitory computer readable medium comprising one or more computer software modules configured to direct one or more processors to: obtain, via a computed tomography (CT) acquisition unit, a reference projection at a reference view angle; obtain, via the CT acquisition unit, at least one sample projection of CT imaging information during rotation of the CT acquisition unit about an object to be imaged; compare an intensity of the at least one sample projection to an intensity of the reference projection, wherein the intensity of the at least one sample projection and the intensity of the reference projection are measured intensities; select a time to perform an imaging scan based on the comparison of the intensity of the at least one sample projection to the intensity of the reference projection; and control the CT acquisition unit to perform the imaging scan based on the selected time. ### Claim 19 (depends on 18) The tangible and non-transitory computer readable medium of claim 18, wherein the computer readable medium is further configured to direct the one or more processors to collect plural candidate projections during a rotation of the CT acquisition unit and select the at least one sample projection from the plural candidate projections based on a similarity of an angle at which the at least one sample projection was obtained to the reference view angle at which the reference projection was obtained. ### Claim 20 (depends on 18) The tangible and non-transitory computer readable medium of claim 18, wherein the computer readable medium is further configured to obtain plural sample projections and determine corresponding intensities of the plural sample projections, and determine a cardiac output based on the corresponding intensities. ### Claim 21 (depends on 18) The tangible and non-transitory computer readable medium of claim 18, wherein the computer readable medium is further configured to direct the one or more processors to obtain plural sample projections at different times, wherein the at least one sample projection is taken along a longitudinal view of the object, and wherein the computer readable medium is further configured to determine a contrast flow rate using the plural sample projections acquired at different times.