Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Heart size and cardiomediastinal contours are stable . Lungs are hyperinflated , similar to prior . Retrocardiac linear opacities likely represent atelectasis , but infection can not be excluded . No pleural effusion or pneumothorax .
    OUTPUT:
    
Retrocardiac linear opacities are likely atelectasis but could represent infection in the appropriate clinical setting .