Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The cardiac silhouette size remains mild to moderately enlarged . Mediastinal and hilar contours are unchanged , and no pulmonary vascular congestion is identified . Linear opacity within the left lung base likely reflects atelectasis . No focal consolidation , pleural effusion or pneumothorax is identified . No acute osseous abnormalities are visualized .
    OUTPUT:
    
Linear opacity in the left lung base most likely reflective of atelectasis .