Method and system for automated computerized analysis of sizes of hearts and lungs in digital chest radiographs
First Claim
1. A method for determining a cardiac contour of a subject from a chest radiograph of the subject, comprising:
- detecting plural right and left cardiac boundary points in the cardiac contour;
fitting a predetermined model function to the detected cardiac boundary points to derive a completed cardiac contour based on the fitted model function;
using a shift-variant sinusoidal function as said predetermined model function; and
producing a representation of the completed cardiac contour.
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Accused Products
Abstract
An automated method and system to determine a number of parameters related to the size and shape of the heart as well as parameters related to the lungs from data derived from digital chest radiographs. A cardiac rectangle enclosing the heart and portions of the surrounding lung tissue is determined, and within the cardiac rectangle, horizontal and vertical profiles, and the first derivatives thereof, are determined. Based on these derivatives, cardiac boundary points on the left and right sides of the cardiac contour are determined, as well as diaphragm edge points. A predetermined model function is then fitted to selected of the determined cardiac boundary points to determine the cardiac contour. Tests are performed to determine whether or not the heart has an abnormal size or is a "tall" heart, and if so, corrective measures are taken. In a preferred embodiment, a shift-variant cosine function is used as a model function fitted to the selected cardiac boundary points. In an alternative embodiment, the model function is equivalent to the partial summation of a Fourier series. In an alternative embodiment for determining cardiac boundaries, an analysis is made of edge gradients obtained in two orthogonal directions in plural narrow band regions of the data from the digital chest radiograph.
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Citations
51 Claims
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1. A method for determining a cardiac contour of a subject from a chest radiograph of the subject, comprising:
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detecting plural right and left cardiac boundary points in the cardiac contour; fitting a predetermined model function to the detected cardiac boundary points to derive a completed cardiac contour based on the fitted model function; using a shift-variant sinusoidal function as said predetermined model function; and producing a representation of the completed cardiac contour. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A method for determining a cardiac contour of a subject from a chest radiograph of the subject, comprising:
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detecting plural right and left cardiac boundary points in the cardiac contour; fitting a predetermined model function to the detected cardiac boundary points to derive a completed cardiac contour based on the fitted model function; using as said model function a function expressed by the summation of a limited number of trigonometrical functions equivalent to a partial summation of a Fourier series; and producing a representation of the completed cardiac contour. - View Dependent Claims (18)
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19. A method for determining a cardiac contour of a subject from a chest radiograph of the subject, comprising:
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detecting plural right and left cardiac boundary points in the cardiac contour; fitting a predetermined model function to the detected cardiac boundary points to derive a completed cardiac contour based on the fitted model function; and producing a representation of the completed cardiac contour; wherein said step of detecting plural right and left cardiac boundary points comprises; determining in said chest radiograph a cardiac rectangle including data from the heart, lungs and diaphragm edges; selecting plural horizontal profiles of the data in said cardiac rectangle, determining the first derivative of selected portions of each horizontal profile, detecting a maximum value of the first derivative in those selected portions of each horizontal profile, and determining the location of each first derivative maximum value to be a possible cardiac boundary point; selecting plural vertical profiles of the data in said cardiac rectangle, determining the first derivative of selected portions of each vertical profile, detecting a maximum value of the first derivative in those selected portions of each vertical profile, and determining the location of each first derivative maximum value obtained from the selected portions of the vertical profiles as diaphragm edge points; and determining whether any of said possible cardiac boundary points overlap said diaphragm points, and if so, rejecting those possible cardiac boundary points which overlap said diaphragm edge points as not being cardiac boundary points. - View Dependent Claims (20, 21, 22, 23, 24, 25)
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26. A system for determining a cardiac contour of a subject from a chest radiograph of the subject, comprising:
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means for producing digital data corresponding to the chest radiograph; means for processing the digital data to detect plural right and left cardiac boundary points in the cardiac contour; means for fitting a predetermined model function to the detected cardiac boundary points to derive a completed cardiac contour based on the fitted model function; and means for producing a representation of the completed cardiac contour; wherein said fitting means fits a shift-variant sinusoidal function to the detected cardiac boundary points. - View Dependent Claims (27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40)
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41. A system for determining a cardiac contour of a subject from a chest radiograph of the subject, comprising:
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means for producing digital data corresponding to the chest radiograph; means for processing the digital data to detect plural right and left cardiac boundary points in the cardiac contour; means for fitting a predetermined model function to the detected cardiac boundary points to derive a completed cardiac contour based on the fitted model function; and means for producing a representation of the completed cardiac contour; wherein said fitting means fits a function expressed by the summation of a limited number of trigonometrical functions equivalent to a partial summation of a Fourier series to said detected cardiac boundary points. - View Dependent Claims (42)
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43. A system for determining a cardiac contour of a subject from a chest radiograph of the subject, comprising:
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means for producing digital data corresponding to the chest radiograph; means for processing the digital data to detect plural right and left cardiac boundary points in the cardiac contour; and means for fitting a predetermined model function to the detected cardiac boundary points to derive a completed cardiac contour based on the fitted model function; and means for producing a representation of the completed cardiac contour; wherein said means for detecting plural right and left cardiac boundary points comprises; means for determining from said digital data a cardiac rectangle including data from the heart, lungs and diaphragm edges; means for selecting plural horizontal profiles of the data in said cardiac rectangle, determining the first derivative of selected portions of each horizontal profile, detecting a maximum value of the first derivative in those selected portions of each horizontal profile, and determining the location of each first derivative maximum value to be a possible cardiac boundary point; means for selecting plural vertical profiles of the data in said cardiac rectangle, determining the first derivative of selected portions of each vertical profile, detecting a maximum value of the first derivative in those selected portions of each vertical profile, and determining the location of each first derivative maximum value obtained from the selected portions of the vertical profiles as diaphragm edge points; and means for determining whether any of said possible cardiac boundary points overlap said diaphragm points, and if so, rejecting those possible cardiac boundary points which overlap said diaphragm edge points as not being cardiac boundary points. - View Dependent Claims (44, 45, 46, 47, 48)
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49. A system for determining a cardiac contour of a subject from a chest radiograph of the subject, comprising:
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means for displaying an image derived from the chest radiograph; means for selecting from the displayed image plural right and left cardiac boundary points in the cardiac contour; means for fitting a predetermined model function to the selected cardiac boundary points to derive a completed cardiac contour based on the fitted model function; and means for producing a representation of the complete cardiac contour; wherein said fitting means fits to the detected cardiac boundary points a predetermined model function selected from the group consisting of a shift-variant sinusoidal function and a function expressed by a summation of a limited number of trigonometrical functions equivalent to a partial summation of a Fourier series.
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50. A method for determining a cardiac contour of a subject from a chest radiograph of the subject, comprising:
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defining in said radiograph a polar coordinate system having an origin at a predetermined point in said radiograph; detecting in said radiograph polar coordinate system polar coordinates of plural right and left cardiac boundary points in the cardiac contour; fitting a predetermined model function to the detected polar coordinates of the plural right and left cardiac boundary points; using as said predetermined model function a function selected from the group consisting of a shift-variant sinusoidal function and a function expressed by a summation of a limited number of trigonometrical functions equivalent to a partial summation of a Fourier series; and producing a representation of the completed cardiac contour based on said model function fitted in said fitting step.
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51. A system for determining a cardiac contour of a subject from a chest radiograph of the subject, comprising:
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means for defining in said radiograph a polar coordinate system having an origin at a predetermined point in said radiograph and for detecting in said radiograph polar coordinate system polar coordinates of plural right and left cardiac boundary points in the cardiac contour; means for fitting a predetermined model function to the detected polar coordinates of the plural right and left cardiac boundary points; and means for producing a representation of the completed cardiac contour based upon said model function fitted by said fitting means; wherein said fitting means fits to the detected cardiac boundary points a predetermined model function selected from the group consisting of a shift-variant sinusoidal function and a function expressed by a summation of a limited number of trigonometrical functions equivalent to a partial summation of a Fourier series.
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Specification