Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: There is a saber sheath configuration of the trachea . Aside from linear atelectasis at both lung bases , the lungs are hyperinflated but clear . The heart and mediastinum are within normal limits . There is no pneumothorax or pleural effusion . There is also a nodular opacity projecting over right lower lobe .
    OUTPUT:
    
Clear lungs , with hyperinflation suggestive of COPD . Etiology of hemoptysis not elucidated . CT may be considered to exclude a radiographically occult cause of Ma purposes if warranted clinically . Nodular opacity projecting over right lower lobe is likely due to the right nipple shadow , however dedicated nipple views or a chest CT may be obtained for confirmation .