US 5,668,888 A · Method and system for automatic detection of ribs and pneumothorax in digital chest radiographs

Abstract

A method and system for the detection of anatomical features in a digital chest radiograph, and in particular rib edges and pneumothorax, wherein vertical profiles are defined in regions of the lungs in the radiograph, and a model function is fitted to the profiles to obtain initial estimates of the locations of rib edges. Gradient-histogram analysis is performed by determining edge gradient and their corresponding orientations in regions of interest (ROIs) defined in the radiograph in the vicinity of the initially estimated rib edges, determining the maximum edge gradient in each of the ROIs, and forming histograms which define accurate detections of rib edges. The edges are fitted with an elliptical function and a representation of the entire rib cage structure is obtained. The method and system are also applied to the detection of pneumothorax where ROIs are defined in the apical lung region and edge gradients and their orientations are detected in the ROIs. The ROI is edge-enhanced using the edge gradients and their orientations and previously detected rib edges are removed. Subtle, curved-line structure corresponding to pneumothorax in the edge-enhanced ROI are detected and a representation of the pneumothorax is obtained using a Hough transform.

Claims33

Dependent claims

A method for the detection of a anatomic feature in a chest radiograph, comprising:

(a) defining plural regions of interest in said radiograph;
(b) determining edge gradients in at least one of said plural regions of interest and corresponding orientations of said edge gradients for each of a plurality of pixels included in said at least one of said regions of interest;
(c) determining a cumulative edge gradient of the edge gradients and corresponding orientations determined in said at least one of said plural regions of interest in step (b) by summing in said at least one of said plural regions of interest the edge gradients having the same orientation;
and
(d) detecting at least one edge of said anatomic feature based upon the cumulative edge gradient determined in said at least one of said plural regions of interest, comprising,
(d1) determining which regions of interest in aid cumulative edge gradient have an orientation within a predetermined range of orientations;
and
(d2) determining a location of an edge of said anatomic feature based on locations of regions of interest which are determined in step (d1) to have said orientation within said predetermined range of orientations;
and
(e) producing a representation of said anatomic feature using said at least one detected edge.

7 more elements

A system for the detection of an anatomic feature in a chest radiograph, comprising:

first means for defining regions of interest in said radiograph;
second means for determining edge gradients in said regions of interest and corresponding orientations of said edge gradients for each of a plurality of pixels included in each of said regions of interest;
third means for determining a respective cumulative edge gradient for each region of interest by summing in each region of interest the edge gradients having the same orientation;
fourth means for detecting at least one edge of said anatomic feature based upon the cumulative edge gradients determined in said plural regions of interest, comprising,
means for determining which of said cumulative edge gradients has a largest sum within a predetermined range of orientations;
and
means for determining an edge of said anatomic region based on a location of the region of interest having in its respective cumulative edge gradient said largest sum within said predetermined range of orientations;
and
fifth means for producing a representation of said anatomic feature using said at least one detected edge.

6 more elements

A method for detection of a pneumothorax in a chest radiograph, comprising:

detecting rib edges in said radiograph;
defining a pneumothorax region of interest in said radiograph which includes said pneumothorax;
removing said rib edges and respective areas adjacent said rib edges from said pneumothorax region of interest;
detecting a curved line in said pneumothorax region of interest having said rib edges removed;
and
producing a representation of said pneumothorax based on the detected curved line;
wherein said step of detecting rib edges comprises:
defining plural regions of interest in said radiograph which include regions containing rib edges;
determining edge gradients and corresponding orientations of the determined edge gradients for each of a plurality of pixels included in each of said regions of interest;
determining a respective cumulative edge gradient for each region of interest by summing in each region of interest the edge gradients of those pixels of the respective region of interest having the same orientation;
determining a rib edge based on the cumulative edge gradients determined in the preceding step, comprising,
determining which of said cumulative edge gradients has a largest sum within a predetermined range of angles;
and
determining said rib edge based on a location of the region of interest having in its respective cumulative edge gradient said largest sum within said predetermined range of orientations.

11 more elements

A system for detection of a pneumothorax in a chest radiograph, comprising:

means for defining rib edge regions of interest and a pneumothorax region of interest;
first means for detecting rib edges in said rib edge regions of interest in said radiograph;
second means for removing said rib edges and respective adjacent areas from said pneumothorax region of interest;
third means for detecting a curved line in said enhanced pneumothorax region of interest having said rib edges removed;
and
fourth means for producing representation of said pneumothorax based on the detected curve line;
wherein said first means comprises:
means for determining edge gradients and corresponding orientations of the determined edge gradients for each of a plurality of pixels included in each of said rib edge regions of interest;
means for determining a respective cumulative edge gradient for each rib edge region of interest by summing the edge gradients of pixels of the respective rib edge region of interest which have the same orientation;
means for determining a rib edge based on said respective cumulative edge gradients, comprising,
means for determining which of said respective cumulative edge gradients has a greatest sum within a predetermined range of orientations, and
means for determining said rib edge based on a location of the region of interest having in its respective cumulative edge gradient said largest sum in said predetermined range of orientations.

9 more elements

Dependencies are inferred from the claim text.

Method and system for automatic detection of ribs and pneumothorax in digital chest radiographs

Life of this patent

Method and system for automatic detection of ribs and pneumothorax in digital chest radiographs

Life of this patent

Abstract

Claims33