Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The lungs are normally expanded . There is left retrocardiac airspace opacity projecting over the spine on the lateral radiograph . Heart size is normal . The mediastinal and hilar contours are normal . There is no pleural effusion or pneumothorax . There is S shaped curvature of the thoracolumbar spine .
    OUTPUT:
    
Left retrocardiac opacity projecting over the spine is worrisome for pneumonia . Recommend followup chest radiographs in 4 weeks after completion of antibiotic therapy to assess for resolution .