Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The right lung is well expanded , while there is improved aeration of the left lung , with partial re-expansion of the previously collapsed left lower lobe . No focal parenchymal opacities are identified . The cardiac silhouette is moderately enlarged , but not significantly changed from prior . A small left - sided pleural effusion persists . There is no pneumothorax .
    OUTPUT:
    
No evidence of pneumonia . Improved aeration of the left lower lobe with mild residual atelectasis and small associated left pleural effusion .