Bronchiectasis with predominantly upper lobe involvement is

More pronounced involvement of the upper lung fields is most common in cystic fibrosis(CF) and is also observed in post radiation fibrosis,corresponding to the lung region encompassed by the radiation po.Bronchiectasis with predominant involvement of the lower lung fields is seen in fibrotic lung diseases or hypogammaglobulinemia.Congenital causes of bronchiectasis with predominant midlung field involvement include the dyskinetic/immotile cilia syndrome or Kaagener's syndrome.Finally,predominant involvement of the central airways is repoed in association with allergic bronchopulmonary aspergillosis. Ref:Harrison's medicine-18th edition,page no:2142.