Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The cardiac , mediastinal and hilar contours are normal . The pulmonary vascularity is normal . The lungs are clear . A trace left pleural effusion is new in the interval . No pneumothorax is identified . Mild degenerative changes are seen in the thoracic spine .
    OUTPUT:
    
Trace left pleural effusion , new in the interval . No radiographic evidence for pneumonia .