Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Lung volumes are slightly low , which may contribute to vascular crowding in the lung bases . The cardiomediastinal silhouette and pulmonary vasculature are unremarkable . There is no pleural effusion or pneumothorax . The lungs are grossly clear .
    OUTPUT:
    
No acute intrathoracic abnormality .