Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The heart size , mediastinal , and hilar contours are normal . There is suggestion of increased opacification in the bilateral lung bases , which appears interstitial . This could simply be a manifestation of chronic pulmonary disease or elevated pulmonary venous pressure . However , in the appropriate clinical setting , pneumonia is considered . There is no pleural effusion or pneumothorax . Osseous structures are unremarkable .
    OUTPUT:
    
1 . Increased opacification of the bilateral lung bases appears interstitial and could be a manifestation of elevated pulmonary venous pressure or chronic pulmonary disease . However , in the appropriate clinical setting , pneumonia is considered .