Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Frontal and lateral chest radiographs demonstrate linear opacities at the bilateral bases , likely reflecting scar . Lung volumes are slightly decreased compared with ___ years prior . There is no significant effusion , or pneumothorax . The cardiac silhouette remains normal in size , the mediastinal contours are notable only for tortuosity of the aorta . Pulmonary vasculature is normal .
    OUTPUT:
    
No acute chest abnormality .