Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Lung volumes are low leading to crowding of bronchovascular structures . Multifocal , linear left basilar atelectasis is again noted . Airspace opacities at the right lung base are slightly increased from the prior examination , and may represent atelectasis although infection is not excluded . There is no large pleural effusion or pneumothorax . The cardiomediastinal silhouette is unchanged .
    OUTPUT:
    
Low lung volumes with increased bibasilar airspace opacities . Findings likely represent atelectasis , although underlying infection is difficult to exclude .