Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Frontal and lateral views of the chest demonstrate hyperexpansion of the lungs and increased AP diameter of the chest , compatible with patient 's underlying chronic obstructive pulmonary disease . The lungs are otherwise clear . No pleural effusion or pneumothorax . Linear opacities in the left lower lobe likely represent scarring . Biapical scarring is also noted . Hilar and mediastinal silhouettes are unremarkable . Aortic arch calcifications are present . Heart is normal in size .
    OUTPUT:
    
No evidence of acute cardiopulmonary process .