Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The heart is normal in size . The mediastinal and hilar contours appear within normal limits . There is a new posterior opacity obscuring the right hemidiaphragm , worrisome for pneumonia . A small pleural effusion accompanying the opacity is possible but not explicitly demonstrated . There is no definite evidence for pleural effusion on the left . The osseous structures are unremarkable .
    OUTPUT:
    
New posterior opacity in the right lower lobe worrisome for pneumonia in the appropriate clinical setting , although atelectasis could also be considered .