Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Low lung volumes are present . The patient is status post median sternotomy and aortic valve replacement . Cardiac silhouette size is mildly enlarged . Thoracic aorta remains calcified . There continues to be mild pulmonary vascular congestion . Persistent streaky opacities at the lung bases appear slightly improved compared to the prior study , and likely reflect atelectasis . There are adjacent small bilateral pleural effusions , though the size of the effusions appearing slightly improved compared to the most recent prior study . No pneumothorax is identified . There are no acute osseous abnormalities .
    OUTPUT:
    
Slight interval improvement in mild pulmonary vascular congestion , small bilateral pleural effusions , and bibasilar airspace opacities likely reflecting atelectasis . Please note that infection at the lung bases can not be completely excluded .