Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: 2 views of the chest show that the lungs are well expanded and show mild interstitial opacities . The cardiac silhouette is enlarged , unchanged . The mediastinal silhouette and hilar contours are normal . No pneumothorax is present . There may be a small left pleural effusion .
    OUTPUT:
    
Mild interstitial edema with a possible left effusion .