Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The lungs are hyperexpanded but clear . Borderline cardiomegaly is chronic . The mediastinal silhouette and hilar contours are normal . No pleural effusion or pneumothorax is present . Mitral annulus calcification is noted , unchanged . Also noted is calcification of the tracheobronchial tree .
    OUTPUT:
    
1 . Chronic obstructive pulmonary disease . Mild chronic cardiomegaly . No acute intrathoracic process .