Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: AP upright and lateral chest radiograph was obtained . The lungs are well expanded and clear aside from unchanged linear opacities in the bases bilaterally , consistent with scarring . There is no pleural effusion or pneumothorax . The heart is normal in size with normal cardiomediastinal contours .
    OUTPUT:
    
No acute intrathoracic process .