Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The cardiomediastinal and hilar contours remain stable . There is no pleural effusion or pneumothorax . The left hemidiaphragm is not as elevated as on the prior study . There has been improvement in the left retrocardiac opacity , consistent with atelectasis . There is no new focal consolidation concerning for pneumonia . Pulmonary vasculature is within normal limits .
    OUTPUT:
    
Improvement of left retrocardiac opacity , likely atelectasis .