Which of these is not a feature of Bronchiectasis?

Bronchiectasis Upper lung fields are commonly involved in cystic fibrosis- commonly involved in infections Oral Glucocoicoids are given for central bronchiectasis of ABPA NTM involve mid zone. HRCT Tram track appearance Signet ring appearance Tree in bud appearance Rx Antibiotic for 10-14 days. NTM infection:Macrolide withrifampin and ethambutol Hydration Mucolytic : Dornase (DNase)-Only for CF-related bronchiectasis Bronchodilator Hypeonic saline Chest physiotherapy Pulmonary rehabilitation Refractory cases: Resection of a focal area Lung transplantation.