Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: AP upright and lateral views the chest provided . Midline sternotomy wires and mediastinal clips are again noted . There is persists and atelectasis in the left lower lung . No convincing signs of pneumonia . No pleural effusion or pneumothorax . Cardiomediastinal silhouette appears stable . Bony structures are intact .
    OUTPUT:
    
Persistent mild left basal atelectasis . No convincing signs of pneumonia .