Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Low lung volumes are noted with secondary left basilar atelectasis . The lungs are otherwise clear . The cardiomediastinal silhouette is within normal limits . No acute osseous abnormalities . Surgical clips in the right upper quadrant suggest prior cholecystectomy .
    OUTPUT:
    
Left basilar opacity which is most likely atelectasis given low lung volumes . Infection is not entirely excluded . If desired repeat with PA and lateral can be performed with better inspiratory effort .