Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Semi-upright portable AP chest radiograph is obtained . There is mild left basilar opacity which could reflect atelectasis . Otherwise , the lungs appear clear . Cardiomediastinal silhouette appears grossly stable though the heart size is somewhat suboptimally assessed . Bony structures appear intact .
    OUTPUT:
    
Left basilar atelectasis .