Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Lung volumes are low leading to crowding of the bronchovascular structures . Bibasilar and , in particular , right middle lobe airspace opacities are again noted . Upper lungs are clear bilaterally . There is no evidence pneumothorax , pleural effusion , or pulmonary edema . The cardiomediastinal silhouette is unchanged .
    OUTPUT:
    
Right middle lobe airspace opacity which appears similar to several prior examinations , and may represent recurrent atelectasis versus pneumonia / aspiration .