Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Single portable view of the chest . Lower lung volumes seen on the current exam with secondary crowding of the bronchovascular markings . Linear opacity at the left lung base most suggestive of atelectasis . Lungs are otherwise clear of confluent consolidation . Cardiomediastinal silhouette is within normal limits . Median sternotomy wires and mediastinal clips are again noted . No free air identified below the diaphragm .
    OUTPUT:
    
No acute cardiopulmonary process .