Automated pneumothorax detection
A method of determining the presence of a pneumothorax includes obtaining a series of frames of image data relating to a region of interest including a pleural interface of a lung. The image data includes at least a first frame and a second frame. The method further includes identifying, via processing circuitry, the pleural interface in at least the first frame and the second frame, determining, based on computing optical flow between the first and second frames, a pleural sliding classification of the image data at the pleural interface, and determining whether a pneumothorax is present in the pleural interface based on the pleural sliding classification.
1. A detection system comprising:
an image sensor configured to obtain image data relating to a region of interest including a pleural interface of a lung; and
an image analyzer in communication with the image sensor to receive the image data therefrom, the image analyzer including processing circuitry configured to:
identify the pleural interface in at least a first frame of the image data and a second frame of the image data;
determine, based on computing optical flow between the first and second frames, a pleural sliding classification of the image data at the pleural interface; and
determine whether a pneumothorax is present in the pleural interface based on the pleural sliding classification.
2. The detection system of claim 1 , wherein the processing circuitry is configured to determine the pleural sliding classification based on clustering of feature vectors indicative of the optical flow based on Euclidean distance to generate clusters that are uniform in direction and spatially adjacent.
3. The detection system of claim 2 , wherein the processing circuitry is configured to determine the pleural sliding classification by employing angular histograms that overlap with the pleural interface of the region of interest using clusters generated by the clustering of the feature vectors.
4. The detection system of claim 3 , wherein the processing circuitry is configured to determine the pleural sliding classification by employing a trained support vector machine to classify the angular histograms.
5. The detection system of claim 4 , wherein the processing circuitry is configured to classify the angular histograms as one of left-sliding, right-sliding and no-sliding to determine the pleural sliding classification.
6. The detection system of claim 1 , wherein the processing circuitry is configured to combine a Hough transform that finds lines in the first and second frames of the image data with brightness thresholding to identify bright lines in the first and second frames of the image data to identify the pleural interface.
7. The detection system of claim 6 , wherein the processing circuitry is further configured to employ a spatial constraint giving preference to bright lines closer to the lungs to locate the pleural interface.
8. The detection system of claim 1 , wherein the image sensor is configured to obtain one of one-dimensional video imagery, two-dimensional video imagery and three-dimensional video imagery of the lungs as the image data.
9. The detection system of claim 1 , wherein the image sensor is provided in a device that is attachable externally to a chest of a patient.
10. The detection system of claim 1 , wherein the processing circuitry is configured to determine whether the pneumothorax is present in the pleural interface by employing a hidden Markov model to analyze the pleural sliding classification relative to a predetermined set of state transition probabilities.
11. The detection system of claim 10 , wherein the predetermined set of state transition probabilities is determined by training the hidden Markov model on an image sequence of known data.