Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The cardiac , mediastinal and hilar contours appear within normal limits . Both lungs are clear with no focal consolidation , pleural effusion or pneumothorax . Minimal previously noted focal opacity of the left lower lung base is not clearly visualized on this study . Minimal left basilar linear atelectasis is noted . Visualized osseous structures are grossly unremarkable .
    OUTPUT:
    
No acute cardiopulmonary process . Minimal linear atelectasis at the left lung base .