Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Marked asymmetric elevation of hemidiaphragm with subsegmental atelectasis in the right lower and middle lobes . More pronounced right upper lobe opacity , when compared to prior radiographs in ___ . This could be pneumonia but it is difficult to separate from sclerosis of the overlying ribs . The left lung is clear . No pneumothorax or large pleural effusions . Mild cardiomegaly .
    OUTPUT:
    
No pneumothorax Marked elevation of the right hemidiaphragm with basal subsegmental atelectasis . More pronounced right upper lobe opacity , when compared to prior radiographs in ___ . This could represent focal pneumonia versus sclerotic bony changes .