Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Single frontal view of the chest demonstrates the patient to be rotated to the left . The heart is top normal in size , but likely accentuated by AP technique . The mediastinal and hilar contours are within normal limits . There is dense retrocardiac opacity which could represent dependent atelectasis , accompanied by a small left pleural effusion . The right base similarly demonstrates streaky opacities , likely atelectasis . There is also a small pleural effusion on the right . There is no pneumothorax .
    OUTPUT:
    
Bibasilar opacities accompanied by small pleural effusions , likely represent compressive atelectasis , although an evolving pneumonia in the left lower lobe can not be excluded purely by imaging appearance .