Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: A portable frontal chest radiograph demonstrates low lung volumes resulting in bronchovascular crowding and prominence of the cardiac silhouette . Allowing for this , the cardiomediastinal silhouette is normal . There is again calcification of the aortic knob . No focal consolidation is identified . Streaky bibasilar opacities likely represent atelectasis or scarring . There is no large pleural effusion or pneumothorax . The visualized upper abdomen is unremarkable .
    OUTPUT:
    
Low lung volumes with bibasilar atelectasis or scarring . No focal consolidation to suggest pneumonia , but dedicated PA and lateral chest radiographs would provide more complete assessment of the lung bases and may be helpful if clinical suspicion for infection persists .