Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The cardiac silhouette is top normal , but no evidence of pulmonary edema . Opacity at the left lower lung base is likely atelectasis . The right lung appears grossly clear with no evidence of opacities or effusions . The bones are intact .
    OUTPUT:
    
No overall change since the prior study ; no evidence of acute intrathoracic process .