Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: A portable frontal chest radiograph demonstrates an unchanged cardiomediastinal silhouette . There is linear atelectasis of the right lower and left mid and lower lungs . The lungs are otherwise clear . There is no pleural effusion or pneumothorax .
    OUTPUT:
    
No pneumothorax . Persistent linear atelectasis of the right lower and left mid and lower lungs .