# US 8,787,519 B2 · System and method of optimizing a representation of dual energy spectral CT images > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,787,519 B2 - Document ID: US8787519B2 - Status: Granted - Kind: B2 - Application number: 13/174,825 - Filed: 2011-07-01 - Published: 2012-02-16 - Granted: 2014-07-22 - Earliest claimed: 2010-08-12 - Assignees: General Electric Company - Applicants: Jiahua Fan; Naveen Chandra; Bruno Kristiaan Bernard De Man - Inventors: Jiahua Fan; Naveen Chandra; Bruno Kristiaan Bernard De Man - Web page: https://patentgrep.com/patent/US8787519B2 ## CPC - A61B 6/482: {involving multiple energy imaging} - A61B 6/032: {Transmission computed tomography [CT]} - A61B 6/4241: {using energy resolving detectors, e.g. photon counting} - A61B 6/5258: {involving detection or reduction of artifacts or noise} - A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D) ## Abstract An imaging system includes an x-ray source, a detector, a data acquisition system (DAS) operably connected to the detector, and a computer operably connected to the DAS. The computer is programmed to obtain CT scan data with two or more incident energy spectra, decompose the obtained CT scan data into projection CT data of a first basis material and a second basis material, generate a first basis material image and a second basis material image using the decomposed projection CT data, generate a first monochromatic image from the first basis material image and the second basis material image at a first energy that is selected based on an amount of correlated noise at the first energy, noise-reduce the first monochromatic image to generate a noise-reduced first monochromatic image, and generate a final monochromatic image based at least on the noise-reduced first monochromatic image. ## Claims ### Claim 1 An imaging system comprising: an x-ray source that emits a beam of x-rays toward an object to be imaged; a detector that receives the x-rays attenuated by the object; a data acquisition system (DAS) operably connected to the detector; and a computer operably connected to the DAS and programmed to: obtain CT scan data with two or more incident energy spectra; decompose the obtained CT scan data into projection CT data of a first basis material and a second basis material; generate a first basis material image and a second basis material image using the decomposed projection CT data; generate a first monochromatic image from the first basis material image and the second basis material image at a first energy that is selected based on an amount of correlated noise at the first energy; noise-reduce the first monochromatic image to generate a noise-reduced first monochromatic image; and generate a final monochromatic image based at least on the noise-reduced first monochromatic image; and wherein the computer is further programmed to: noise-reduce the first basis material image to generate a noise-reduced first basis material image; generate a noise-reduced second basis material image using the noise-reduced first monochromatic image and the noise-reduced first basis material image; and generate the final monochromatic image using the noise-reduced second basis material image. ### Claim 2 (depends on 1) The imaging system of claim 1 wherein the first basis material image is one of an iodine image and a water image. ### Claim 3 (depends on 1) The imaging system of claim 1 wherein the computer is programmed to generate the first monochromatic image at the first energy, wherein the first energy is selected based on an amount of negatively correlated noise at the first energy. ### Claim 4 (depends on 3) The imaging system of claim 3 wherein the amount of negatively correlated noise is minimized at the first energy. ### Claim 5 (depends on 1) The imaging system of claim 1 wherein the computer is programmed to: generate a second monochromatic image from the first basis material image and the second basis material image at a second energy that is selected based on an amount of correlated noise at the second energy; noise-reduce the second monochromatic image to generate a noise-reduced second monochromatic image; and generate the final monochromatic image based on the noise-reduced second monochromatic image. ### Claim 6 (depends on 5) The imaging system of claim 5 wherein the computer is programmed to generate the second monochromatic image at the second energy that is selected based on an amount of negatively correlated noise at the second energy. ### Claim 7 (depends on 6) The imaging system of claim 6 wherein the amount of negatively correlated noise is dominant at the second energy. ### Claim 8 (depends on 5) The imaging system of claim 5 wherein the computer is programmed to: generate a noise-reduced first basis material image from the noise-reduced first monochromatic image and the noise-reduced second monochromatic image; generate a noise-reduced second basis material image from the noise-reduced first monochromatic image and the noise-reduced second monochromatic image; and generate the final image using the noise-reduced first basis material image and the noise-reduced second basis material image. ### Claim 9 A method of imaging comprising: obtaining a low kVp dataset and a high kVp dataset; decomposing the low kVp dataset and the high kVp dataset into a first basis material image and a second basis material image; generating a first monochromatic image from the first basis material image and the second basis material image at a first energy that is selected based on an amount of correlated noise; generating a second monochromatic image from the first basis material image and the second basis material image at a second energy that is selected based on an amount of correlated noise; noise-reducing the first monochromatic image to generate a noise-reduced first monochromatic image; noise reducing the second monochromatic image to generate a noise-reduced second monochromatic image; and generating a final image based on the noise-reduced first monochromatic image and the noise-reduced second monochromatic image. ### Claim 10 (depends on 9) The method of claim 9 wherein the first basis material is one of water and iodine. ### Claim 11 (depends on 9) The method of claim 9 wherein generating the first monochromatic image is at the first energy that is based on an amount of negatively correlated noise. ### Claim 12 (depends on 11) The method of claim 11 wherein the amount of negatively correlated noise is minimized. ### Claim 13 (depends on 9) The method of claim 9 comprising: generating a noise-reduced first basis material image using the noise-reduced first monochromatic image and the noise-reduced second monochromatic image; generating a noise-reduced second basis material image using the noise-reduced first monochromatic image and the noise-reduced second monochromatic image; and generating the final image using the noise-reduced first basis material image and the noise-reduced second basis material image. ### Claim 14 (depends on 9) The method of claim 9 comprising noise-reducing the first basis material image to generate a noise-reduced first basis material image. ### Claim 15 (depends on 14) The method of claim 14 comprising generating a noise-reduced second basis material image using the noise-reduced first monochromatic image and the noise-reduced first basis material image. ### Claim 16 A non-transitory computer-readable storage medium having stored thereon a computer program which, when executed by a computer, will cause the computer to: obtain low kVp and high kVp projection datasets; decompose the low kVp and the high kVp projection datasets into a first basis material image and a second basis material image; generate a first monochromatic image from the first basis material image and the second basis material image at a keV that is selected based on an amount of correlated noise; minimize noise in the first monochromatic image to generate a noise-minimized first monochromatic image; generate a second monochromatic image from the first basis material image and the second basis material image at a keV that is selected based on an amount of correlated noise; minimize noise in the second monochromatic image to generate a noise-minimized second monochromatic image; and generate a final image based on the noise-minimized first monochromatic image and the noise-minimized second monochromatic image. ### Claim 17 (depends on 16) The non-transitory computer-readable storage medium of claim 16 wherein the computer is programmed to generate the first monochromatic image at a keV where non-negatively correlated noise is minimized. ### Claim 18 (depends on 16) The non-transitory computer-readable storage medium of claim 16 wherein the computer is programmed to: generate a noise-minimized first basis material image using the noise-minimized first monochromatic image and the noise-minimized second monochromatic image; generate a noise-minimized second basis material image using the noise-minimized first monochromatic image and the noise-minimized second monochromatic image; and generate the final image using the noise-minimized first basis material image and the noise-minimized second basis material image. ### Claim 19 An imaging system comprising: an x-ray source that emits a beam of x-rays toward an object to be imaged; a detector that receives the x-rays attenuated by the object; a data acquisition system (DAS) operably connected to the detector; and a computer operably connected to the DAS and programmed to: obtain CT scan data with two or more incident energy spectra; decompose the obtained CT scan data into projection CT data of a first basis material and a second basis material; generate a first basis material image and a second basis material image using the decomposed projection CT data; generate a first monochromatic image from the first basis material image and the second basis material image at a first energy that is selected based on an amount of correlated noise at the first energy; noise-reduce the first monochromatic image to generate a noise-reduced first monochromatic image; and generate a final monochromatic image based at least on the noise-reduced first monochromatic image; and wherein the computer is further programmed to: generate a second monochromatic image from the first basis material image and the second basis material image at a second energy that is selected based on an amount of correlated noise at the second energy; noise-reduce the second monochromatic image to generate a noise-reduced second monochromatic image; and generate the final monochromatic image based on the noise-reduced second monochromatic image. ### Claim 20 A method of imaging comprising: obtaining a low kVp dataset and a high kVp dataset; decomposing the low kVp dataset and the high kVp dataset into a first basis material image and a second basis material image; noise-reducing the first basis material image to generate a noise-reduced first basis material image; generating a first monochromatic image from the first basis material image and the second basis material image at a first energy that is selected based on an amount of correlated noise; noise-reducing the first monochromatic image to generate a noise-reduced first monochromatic image; generating a noise-reduced second basis material image using the noise-reduced first monochromatic image and the noise-reduced first basis material image and generating a final image based on the noise-reduced first monochromatic image.