Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: There is moderate cardiomegaly which is unchanged compared to previous studies . The left hilum is enlarged but stable . No pleural effusion or pneumothorax are seen . There is an opacity of left lower lobe that likely reflects developing pneumonia versus atelectasis .
    OUTPUT:
    
Left lower lobe opacification that represents developing pneumonia versus atelectasis .