Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: There are low lung volumes . The cardiomediastinal silhouettes are stable . The bilateral hila are unremarkable . Retrocardiac opacity is decreased from prior study , possibly atelectasis and scarring from prior pneumonia . There is no pulmonary vascular congestion . There is no pneumothorax or pleural effusion . There is a large hiatus hernia .
    OUTPUT:
    
1 . Decreased conspicuity of previously visualized retrocardiac opacity in the left lower lobe . While this may represent residual scarring and / or atelectasis . No evidence of focal consolidation elsewhere . 2 . Large hiatus hernia .