Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Linear opacity in the left lung base is unchanged from prior and may represent focal scarring . Remainder of the lungs are clear . There is no confluent consolidation , vascular congestion or interstitial edema . No pleural effusions are identified . There is no pneumothorax . Cardiomediastinal and hilar contours are within normal limits .
    OUTPUT:
    
No acute cardiopulmonary process .