Evaluation of Geometric Differences Between Right and Left Lungs in Bacterial Pneumonia Chest Radiographs

In this study, an analysis is performed to evaluate the geometric differences between the right and left lungs associated with bacterial pneumonia using chest radiographs. For this, the chest radiographic images of pediatric patients are considered. Segmentation of the right and left lungs are performed using the Reaction-Diffusion Level Set (RDLS) method. Feature determinants such as area, minor axis length, circularity, and orientation are extracted from both the right and left lungs. An asymmetry index between the right and the left lung is proposed and is derived from the extracted geometric features. The contribution of individual right and left lungs to the asymmetry index is analyzed in detail. The results demonstrate that the RDLS method is able to precisely segment the right and left lungs by preserving the structural alterations. Variations in the asymmetry indices are observed among the considered images indicating the effect of localized abnormalities. Left lung features are found to be better correlated with the asymmetry indices indicating a higher contribution of the left lung features as compared to the right lung features. This study demonstrates the possibility that structural alterations in bacterial pneumonia can be characterized using the lung asymmetry indices. It can be used as a potential noninvasive biomarker for the diagnosis of pulmonary abnormalities.