Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The heart size remains mildly enlarged but unchanged . The aorta is tortuous . The mediastinal and hilar contours otherwise are stable . There is no pulmonary vascular congestion . Patchy opacities are demonstrated in both lung bases , right more so than left , which could reflect atelectasis but infection can not be excluded , particularly in the right lung base . No pleural effusion or pneumothorax is identified . There are no acute osseous abnormalities .
    OUTPUT:
    
Bibasilar airspace opacities may reflect atelectasis though infection can not be completely excluded .