Nodule detection
AssigneeMedicsight PLC
InventorJamshid Dehmeshki
Life of this patent
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Abstract
A method of detecting a nodule in a three-dimensional scan image comprises calculating a three-dimensional sphericity index for each point in the scan image (310-330), applying a high sphericity threshold to the sphericity index (340) to obtain a candidate nodule region, and then performing region-growing (350) from the candidate region using a relaxed sphericity threshold to determine an extended region including less spherical parts connected to the candidate region. Optionally, spherical filtering may be applied to the image by matching the spherical filter to the extended region.
Claims23
A method of identifying a nodule in a computed tomography scan image of at least part of a lung, comprising:
- a. calculating a sphericity index map of a plurality of points within the image;
- b. identifying a region of high sphericity within the image by identifying connected ones of said points having a sphericity index above a predetermined high sphericity index threshold as belonging to said region;
- c. performing three-dimensional region growing from said region by adding to said region ones of said points having a sphericity index above a relaxed sphericity index threshold, said relaxed sphericity index threshold being lower than said high sphericity index threshold, to form an extended region;
- and
- d. outputting, said extended region as an identified nodule.
A method of identifying a nodule in a computed tomography scan image of at least part of a lung, comprising:
- a. identifying a region of high sphericity within the image;
- b. extending the region to include connected points of lower sphericity;
- c. performing filtering around the extended region using a spherical filter comprising an inner spherical region of positive weight and an outer spherical region of negative weight, to form a filtered extended region;
- and
- d. outputting said filtered extended region as an identified nodule.
A method of identifying a nodule in a computed tomography scan image of at least part of a lung, comprising:
- a. calculating a sphericity index map of a plurality of points within the image;
- b. identifying a region of high sphericity within the image by identifying connected ones of said points having a sphericity index above a predetermined high sphericity index threshold as belonging to said region;
- c. extending the region to include connected points of lower sphericity, to form an extended region;
- d.performing filtering around the extended region using a spherical filter comprising an inner spherical region of positive weight and an outer spherical region of negative weight, wherein the filtering comprises convolving the inner and outer spherical regions with the sphericity index map, to form a filtered extended region;
- and
- e. outputting the filtered extended region as an identified nodule.
Apparatus for identifying a nodule in a computed tomography scan image of at least part of a lung, comprising:
- means for identifying a region of high sphericity within the image, including means for calculating a sphericity index map of a plurality of points within the image, and for identifying connected points having a sphericity index above a predetermined high sphericity index threshold as belonging to said region;
- means for extending the region by performing three-dimensional region growing from said region to add connected points having a sphericity index above a relaxed sphericity index threshold, said relaxed sphericity index threshold being lower than said high sphericity index threshold, to form an extended region;
- and
- means for outputting the extended region as an identified nodule.
Apparatus for identifying a nodule in a computed tomography scan image of at least part of a lung, comprising:
- means for calculating a sphericity index map of a plurality of points within the image;
- means for identifying a region of high sphericity within the image by identifying connected ones of said points having a sphericity index above a predetermined high sphericity index threshold as belonging to said region;
- means for performing three-dimensional region growing from said region to add connected points of lower sphericity, to form an extended region;
- means for performing filtering around the extended region using a spherical filter comprising an inner spherical region of positive weight and an outer spherical region of negative weight, wherein the filtering comprises convolving the inner and outer spherical regions with the sphericity index map, to form a filtered extended region;
- and
- means for outputting the filtered extended region as an identified nodule.
A computer readable storage medium having recorded thereon program code to perform the following processes for identifying a nodule in a computed tomography scan image of at least part of a lung:
- a. calculating a sphericity index map of a plurality of points within the image;
- b. identifying a connected region of high sphericity index within the image by identifying connected ones of said points having a sphericity index above a predetermined high sphericity index threshold as belonging to said connected region;
- c. performing three-dimensional region growing from said connected region to add connected points of lower sphericity, to form an extended region;
- d. performing filtering around the extended region using a spherical filter comprising an inner spherical region of positive weight and an outer spherical region of negative weight, wherein the filtering comprises convolving the inner and outer spherical regions with the sphericity index map, to form a filtered extended region;
- and
- e. outputting the filtered extended region as an identified nodule.
An article comprising a computer readable storage medium for storing instructions to enable a processor-based system to:
- a. calculate a sphericity index map of a plurality of points within a computed tomography scan image of at least part of a lung;
- b. identify a region of high sphericity within the image by identifying connected ones of said points having a sphericity index above a predetermined high sphericity index threshold as belonging to said region;
- c. extend the region to include connected points of lower sphericity, to form an extended region;
- d. perform filtering around the extended region using a spherical filter comprising an inner spherical region of positive weight and an outer spherical region of negative weight, wherein the filtering comprises convolving the inner and outer spherical regions with the sphericity index map, to form a filtered extended region;
- and
- e. output the filtered extended region as an identified nodule.
A computer readable storage medium having recorded thereon program code to perform the following processes for identifying a nodule in a computed tomography scan image of at least part of a lung:
- a. calculating a sphericity index map of a plurality of points within the image;
- b. identifying a region of high sphericity within the image by identifying connected ones of said points having a sphericity index above a predetermined high sphericity index threshold as belonging to said region;
- c. performing three-dimensional region growing from said region by adding to said region ones of said points having a sphericity index above a relaxed sphericity index threshold, said relaxed sphericity index threshold being lower than said high sphericity index threshold, to form an extended region;
- and
- d. outputting said extended region as an identified nodule.
An article comprising a computer readable storage medium for storing instructions to enable a processor-based system to:
- a. calculate a sphericity index map of a plurality of points within a computed tomography scan image of at least part of a lung;
- b. identify a region of high sphericity within the image by identifying connected ones of said points having a sphericity index above a predetermined high sphericity index threshold as belonging to said region;
- c. perform three-dimensional region growing from said region by adding to said region ones of said points having a sphericity index above a relaxed sphericity index threshold, said relaxed sphericity index threshold being lower than said high sphericity index threshold, to form an extended region;
- and
- d. output said extended region as an identified nodule.
Dependencies are inferred from the claim text.