Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: AP upright and lateral views of the chest were provided . The endotracheal tube previously noted has been removed . Callus formation involving a left sixth posterolateral rib arch casts a focal rounded density over the lateral left mid lung . The lungs appear clear bilaterally without definite signs of pneumonia or CHF . The lungs are somewhat hyperinflated with flattened diaphragms which could be indicative of underlying emphysema . No large effusion or pneumothorax is seen . The heart and mediastinal contour appear stable with atherosclerosis involving the unfolded thoracic aorta . The imaged osseous structures appear unchanged .
    OUTPUT:
    
Healing left sixth rib fracture . No acute intrathoracic process .