Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Lung volumes are lower compared to the prior exam . The left hemidiaphragm is elevated secondary to gaseous distension of bowel , incompletely visualized . No pleural effusion , pneumothorax , focal consolidation , or edema . Bibasilar atelectasis is mild . The cardiomediastinal silhouette is unchanged . Median sternotomy wires and mediastinal clips are intact and unchanged in position .
    OUTPUT:
    
No convincing evidence of pneumonia . Lower lung volumes , perhaps in the setting of stomach distension .