Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Previously seen rounded opacity projecting over the right fifth posterior rib is not identified on current study , likely an external structure has since been removed . Lung volumes are normal . There is no focal consolidation , effusion or pneumothorax . Mediastinal and hilar contours are normal . Heart size normal .
    OUTPUT:
    
No acute intrathoracic process . Previously identified rounded opacity projecting over the fifth posterior rib is no longer visualized .