Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Low lung volumes are present . Cardiac silhouette size is mildly enlarged , similar to the prior study . Mediastinal and hilar contours are unremarkable . There is crowding of bronchovascular structures but no overt pulmonary edema . Patchy opacities in lung bases may reflect atelectasis . No pleural effusion or pneumothorax is present . No acute osseous abnormality is visualized .
    OUTPUT:
    
Low lung volumes . Patchy opacities in the lung bases may reflect areas of atelectasis , but infection or aspiration can not be fully excluded in the correct clinical setting .