Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: There is moderate to severe tracheal narrowing due to the enlarged thyroid seen on ___ . The lung volumes are normal . Normal size of the cardiac silhouette . Normal hilar and mediastinal structures . . No pneumonia , no pulmonary edema . No pleural effusions .
    OUTPUT:
    
Moderate to severe tracheal narrowing due to enlarged thyroid . Otherwise , normal chest radiograph