Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: AP upright and lateral chest radiographs demonstrate mildly low lung volumes . Lungs are clear without a focal opacity . Cardiomediastinal and hilar contours are stable . There is no pleural effusion or pneumothorax . Streaky opacity at the left lung base likely reflects atelectasis . No air under the right hemidiaphragm is present .
    OUTPUT:
    
No acute intrathoracic abnormality .