Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: AP portable upright view of the chest . Mild left basal atelectasis noted . Otherwise lungs are clear . No large effusion or pneumothorax . No signs of congestion or edema . The cardiomediastinal silhouette is normal . Imaged osseous structures are intact . No free air below the right hemidiaphragm .
    OUTPUT:
    
No acute intrathoracic process