Method of deriving a cardiac ejection fraction from nuclear image data

Claim 1

A method for deriving the cardiac ejection fraction of a patient comprising the steps of: (a) during a cardiac cycle, sequentially acquiring a series of electronic images, M in number, containing heart blood volume information; (b) defining an area which encloses heart blood volume information in one of the images; (c) extracting the blood volume information from the defined area in each of the images in the series and producing a first digital signal representation of blood volume for each image; (d) using the first digital signal representations of blood volume to determine a diastolic blood volume digital signal value; (e) for a plurality, P in number, of consecutive images including the image from which a smallest magnitude digital signal representation was produced, individually for each image defining an area which encloses heart blood volume information and producing a second digital signal representation of heart blood volume for that image, where P is less than M-1; (f) defining the second digital signal representation of blood volume which has the smallest magnitude as a systolic blood volume digital signal value; and (g) calculating the cardiac ejection fraction from the diastolic and systolic blood volume digital signal values.

Claim 2

A method for deriving the cardiac ejection fraction of a patient comprising the steps of: (a) during a cardiac cycle, sequentially acquiring a series of electronic images, M in number, containing heart blood volume information; (b) defining an area which encloses heart blood volume information in one of the images; (c) extracting the blood volume information from the defined area in each of the images in the series and producing a first digital signal representation of blood volume for each image; (d) using the first digital signal representations of blood volume to determine a diastolic blood volume digital signal value; (e) for a plurality, P in number, of consecutive images including the image from which a smallest magnitude digital signal representation was produced, individually for each image defining an area which encloses heart blood volume information and producing a second digital signal representation of heart blood volume for that image, where P is less than M-1; (f) defining the second digital signal representation of blood volume which has the smallest magnitude as a systolic blood volume digital signal value; and (g) calculating the cardiac ejection fraction from the diastolic and systolic blood volume digital signal values.

Claim 7

A method for deriving the cardiac ejection fraction of a patient comprising the steps of: (a) during a cardiac cycle, acquiring a sequence of images, numbered by integers 1 through M, in which each image contains heart blood volume information; (b) storing the acquired images in a memory means; (c) defining an area in one of the stored images, designated image N, which area substantially encloses heart blood volume information; (d) extracting the blood volume information from the defined area in each of the M stored images to produce a digital signal representation of blood volume for each image; (e) defining a digital signal representation of blood volume as representing diastolic blood volume; (f) identifying an image, designated by integer R, from which was produced a digital signal representation of blood volume having the smallest magnitude; (g) for each image of a sequence of consecutive images numbered R-S through R+T, where S and T are non-negative integers, individually defining an area in each image which encloses heart blood volume information and producing another digital signal representation of heart blood volume; (h) defining a digital signal representation of heart blood volume within the ones produced in step (g), which has the smallest magnitude, as representing systolic blood volume; and (i) calculating the cardiac ejection fraction from the diastolic and systolic blood volume digital signal values.

Claim 8

A method for deriving the cardiac ejection fraction of a patient comprising the steps of: (a) during a cardiac cycle, acquiring a sequence of images, numbered by integers 1 through M, in which each image contains heart blood volume information; (b) storing the acquired images in a memory means; (c) defining an area in one of the stored images, designated image N, which area substantially encloses heart blood volume information; (d) extracting the blood volume information from the defined area in each of the M stored images to produce a digital signal representation of blood volume for each image; (e) defining a digital signal representation of blood volume as representing diastolic blood volume; (f) identifying an image, designated by integer R, from which was produced a digital signal representation of blood volume having the smallest magnitude; (g) for each image of a sequence of consecutive images numbered R-S through R+T, where S and T are non-negative integers, individually defining an area in each image which encloses heart blood volume information and producing another digital signal representation of heart blood volume; (h) defining a digital signal representation of heart blood volume within the ones produced in step (g), which has the smallest magnitude, as representing systolic blood volume; and (i) calculating the cardiac ejection fraction from the diastolic and systolic blood volume digital signal values.

Claim 11

A method for deriving the cardiac ejection fraction of a patient comprising the steps of: (a) sequentially acquiring series of nuclear images of a heart during a cardiac cycle in which each image is formed by a plurality of radiation counts; (b) as each image of the series is acquired, storing the image in a memory; (c) defining a perimeter of the left ventricle of the heart in one of the images stored in the memory; (d) for each image of the series, summing the radiation counts located in the image within the previously defined perimeter; (e) if the image for which the perimeter was defined in step (c) does not have the largest sum of the radiation counts, then defining a new perimeter of the left ventricle of the heart in the stored image which has the largest sum as calculated at step (d) and producing a new sum of the radiation counts located within the new perimeter in this latter image, this new sum being designated "DIAS SUM", otherwise the sum having the greatest magnitude calculated at step (d) being designated "DIAS SUM"; (f) individually for each image, in a group of consecutive images that includes the image from which a smallest radiation count sum is calculated at step (d), defining a perimeter of the left ventricle of the heart and summing the radiation counts within that perimeter, the radiation count sum produced in the present step which has the smallest magnitude being designated "SYST SUM"; and (g) calculating the cardiac ejection fraction in response to the DIAS SUM and the SYST SUM.

Claim 12

A method for deriving the cardiac ejection fraction of a patient comprising the steps of: (a) sequentially acquiring series of nuclear images of a heart during a cardiac cycle in which each image is formed by a plurality of radiation counts; (b) as each image of the series is acquired, storing the image in a memory; (c) defining a perimeter of the left ventricle of the heart in one of the images stored in the memory; (d) for each image of the series, summing the radiation counts located in the image within the previously defined perimeter; (e) if the image for which the perimeter was defined in step (c) does not have the largest sum of the radiation counts, then defining a new perimeter of the left ventricle of the heart in the stored image which has the largest sum as calculated at step (d) and producing a new sum of the radiation counts located within the new perimeter in this latter image, this new sum being designated "DIAS SUM", otherwise the sum having the greatest magnitude calculated at step (d) being designated "DIAS SUM"; (f) individually for each image, in a group of consecutive images that includes the image from which a smallest radiation count sum is calculated at step (d), defining a perimeter of the left ventricle of the heart and summing the radiation counts within that perimeter, the radiation count sum produced in the present step which has the smallest magnitude being designated "SYST SUM"; and (g) calculating the cardiac ejection fraction in response to the DIAS SUM and the SYST SUM.