Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Lung volumes are low . This accentuates the size of the heart and mediastinal contours , with the heart size appearing mildly enlarged . The aorta is unfolded . No hilar enlargement is seen , and there is no pulmonary vascular congestion . Hazy bibasilar opacities likely reflect atelectasis . No pleural effusion or pneumothorax is present . There are no acute osseous abnormalities .
    OUTPUT:
    
Low lung volumes limit assessment of the lung bases . Probable bibasilar atelectasis , though infection is difficult to exclude .