Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: No pleural effusion or evidence of pneumothorax is seen . There is mild left base retrocardiac linear atelectasis / scarring . No definite focal consolidation is seen . Cardiac and mediastinal silhouettes are unremarkable , with the cardiac silhouette top - normal .
    OUTPUT:
    
Linear in configuration left base retrocardiac opacity seen on the frontal view , most likely representing atelectasis . No definite focal consolidation seen .