Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Single frontal view of the chest was provided . As compared with multiple prior exams , the appearance of the chest is stable with vague basilar opacities , likely representing scarring or atelectasis . The possibility of pneumonia is difficult to exclude though given the stability over time , chronic scarring or atelectasis is favored . No large effusion is seen , though the CP angles are partially excluded bilaterally . Heart size is top normal . Mediastinal contour normal . Tracheobronchial tree calcification noted . Clips to the right of the upper trachea in the superior mediastinum are likely from prior thyroid resection . Bony structures are intact .
    OUTPUT:
    
Stable exam without definite signs of pneumonia or CHF . Lower lung opacities are stable over time and likely represents scarring or chronic atelectasis .