Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: PA and lateral views of the chest were provided . Since the prior exam , there is increased opacity at the right lung base which could represent a combination of atelectasis and effusion , though underlying pneumonia is difficult to exclude in the correct clinical setting . Lung volumes and evaluation for mild pulmonary edema is limited . There is no overt edema . No pneumothorax is seen . Bony structures appear intact .
    OUTPUT:
    
Increased opacity at the right lung base , likely a combination of effusion and atelectasis , though underlying pneumonia difficult to exclude .