Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: AP upright portable chest radiograph obtained . There is left basilar atelectasis . Midline sternotomy wires and mediastinal clips are noted . There is no definite sign of pneumonia or CHF . No pleural effusion or pneumothorax . Cardiomediastinal silhouette appears normal . Bony structures are intact .
    OUTPUT:
    
Mild left basilar atelectasis . Otherwise , normal study .