Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Linear opacity within the lung bases likely reflect subsegmental atelectasis . There is mild blunting of bilateral costophrenic angles , left greater than right , findings consistent with small effusions or pleural thickening . Cardiomediastinal and hilar contours are within normal limits . Median sternotomy wires are intact . A prosthetic cardiac valve is noted .
    OUTPUT:
    
Minimal bibasilar atelectasis . No edema or confluent consolidation .