IS Case 84: Cystic Fibrosis

Ben Wandtke, MD

Imaging Sciences URMC 2008
Publication Date: 2009-05-20


Patient is a teenage male with hypoxia and shortness of breath.


Plain films demonstrate hyperinflation and predominantly upper lobe bronchiectasis. "Signet ring sign" - CT finding of dilated bronchus with adjacent smaller artery consistent with bronchiectasis. "Tree-in-bud" - CT finding of thickened secretions within peripheral centrilobular bronchioles. This finding is more commonly associated with infectious etiologies and is non-specific. Mucoid impaction ("finger in glove") may result in focal, often chronic atelectasis.


Cystic Fibrosis


Cystic fibrosis is an autosomal recessive inherited disease predominantly affecting caucasians. Pathologic changes result from deficient chloride transport yielding thickened, viscous secretions. In the lungs, this leads to recurrent pulmonary infections which damage the airways over time. Colonization with pseudomonas is common. The pancreas, GI tract, liver, and sinuses are also frequently affected.

Clinical features include progressive respiratory failure, pansinusitis, cirrhosis, pancreatic insufficiency, and delayed sexual development. Clinical diagnosis is obtained via sweat test.

The radiologic differential diagnosis includes recurrent aspiration, asthma, Kartagener's syndrome, and immune deficiency states.


  1. Helbich TH, Heinz-Peer G, Eichler I, et al. Cystic fibrosis: CT assessment of lung involvement in children and adults. Radiology. 1999 Nov;213(2):537-44. [PMID: 10551238]
  2. Stern RC. The diagnosis of cystic fibrosis. N Engl J Med. 1997 Feb 13;336(7):487-91. [PMID: 9017943]

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