Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Slight increased retrocardiac opacity on the lateral view could potentially reflect an early pneumonia . No edema , effusion , or pneumothorax . No pleural effusion . The heart is normal in size . No mediastinal widening . No acute osseous abnormality .
    OUTPUT:
    
Increased retrocardiac opacity may reflect an early lower lobe pneumonia in the appropriate clinical situation .