Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: PA and lateral views of the chest . There is better aeration of the lungs bilaterally compared to prior study . There is some residual left basilar retrocardiac atelectasis . No pleural effusion or pneumothorax . The cardiomediastinal and hilar contours are normal .
    OUTPUT:
    
Improved aeration of the lungs bilaterally and mild residual retrocardiac atelectasis .