Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Frontal and lateral radiographs of the chest demonstrate well expanded lungs . Note is made of a subtle opacity in the right mid lung , which is not definitely seen on the lateral view . It is unclear if this finding is within the lung , or due to overlapping structures . The cardiomediastinal and hilar contours are unremarkable . There is no pneumothorax , pleural effusion , or consolidation .
    OUTPUT:
    
1 . Subtle opacity in the right mid lung is of uncertain etiology . Could overlap of structures versus pulmonary nodule .