Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Frontal and lateral views of the chest were obtained . The lungs are well expanded . Subtle opacity at the left lung base may be early or developing pneumonia in the appropriate clinical setting . There is no consolidation . No pneumothorax or pleural effusion . Heart size is normal . The mediastinal silhouette and hilar contours are normal . No acute osseous abnormality is identified . There is no free intraperitoneal air .
    OUTPUT:
    
Subtle opacity at the left lung base may be early or developing pneumonia in the appropriate clinical setting .