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Cardiogenic pulmonary edema is a major cause of pulmonary edema. With methods presently available, pulmonary edema can only be detected clinically, late in its course, making prompt therapy of the developing condition virtually impossible. The detection of an early rise in pulmonary venous pressure could allow institution of therapy and possibly prevent pulmonary edema and its accompanying morbidity and mortality. It has been shown experimentally that as pulmonary venous pressures rise, there is a redistribution of blood flow in the lungs. A prototype optical-digital system for automatic processing of coal worker's pneumoconiosis chest radiographs has been developed. With the optical system it is well known that high frequency information pertains to the amount of sharpness of edge information in an image. From experience with the prototype system, it was hypothesized that lung regions with more vascularity would generate more of this high frequency than a region of lung with few vessels, and that pulmonary vascular patterns could be extracted using the Fraunhofer diffraction pattern sampling unit. To examine the effect of the number of vessels in annular ring and wedge signatures, a study was made of straight line patterns which might simulate different categories of redistribution. Different patterns were characterized by plotting the normalized energies of the annular rings and wedges. An interactive, non statistical prediction was made on a test set of line patterns with an accuracy rate of 95%. Spatial frequency signatures were recorded using radiographs, carried out by removing an upper lung and lower lung region. These regions were rotated and interchanged and these signatures were recorded. Interactive, non statistical predictions were made on a test set of these radiographic sections with an accuracy rate of 90%. Derived features from a test set of 15 normal and 24 abnormal (2+ re-distribution) radiographs were submitted to a non-interactive stepwise discriminant analysis procedure (BMDO7M) which yielded an accuracy rate of 95% using three features. These preliminary results are encouraging and suggest that automatic processing of chest radiographs might yield estimates of the pulmonary venous pressure.
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