Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Lung volumes are low . No focal consolidation , pleural effusion , pneumothorax , or pulmonary edema is detected . Retrocardiac opacity on frontal view likely represents atelectasis . Heart size is slightly enlarged but likely exaggerated by low lung volumes . Mediastinal contours are within normal limits .
    OUTPUT:
    
No acute findings , but soft tissue thickness makes it difficult to exclude mild interstitial abnormality .