Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: AP upright portable chest radiograph obtained . The left chest wall Port - A - Cath is again noted with its catheter tip extending to level of the SVC , unchanged . Low lung volumes , though no clear signs of pneumonia or CHF . Linear density at the left lung base is most compatible with plate - like atelectasis . No consolidation or large masses . Bony structures are intact . Cardiomediastinal silhouette is stable .
    OUTPUT:
    
Mild left basal atelectasis . No signs of pneumonia .