Frontal chest x-ray in Cystic Fibrosis illustrates diffuse interstitial disease. Interstitial disease is a name given to a collection of lung disorders (including Cystic Fibrosis) that affect the interstitium which is the tissue around the air sacs, or alveoli, in the lungs. This lung tissue becomes inflamed and damaged . Also evident is bronchiectasis; this is an abnormal widening of the main bronchial airways and their branches. There are also nodular densities; (with impacted mucus) these appear as white, rounded shadows and are small masses of tissue in the lungs. Findings: Known Cystic Fibrosis.
As demonstrated in the above image, findings on chest x-ray can be non-specific because the same features occur in many disorders, especially those that exhibit destructive or inflammatory changes of the airways. Another problem with plain radiography in the earlier stages of Cystic Fibrosis is that the x-rays can appear normal or the changes may be very minor, typically showing early signs such as mild hyperinflation of the lungs and minimal bronchial thickening. Hyperinflation is a sign that there is obstruction in the bronchial airways and the air gets trapped in the lung causing it to overinflate. This symptom however, is also common in Chronic Obstructive Pulmonary Disease (COPD) and asthma. Plain chest radiography can help endorse a diagnosis of Cystic Fibrosis and is also very useful in assessing the progress of the disease over the course of time.(1) CT scan is more sensitive and can demonstrate bronchiectasis and other lung diseases more clearly in patients who are symptomatic but have normal chest x-rays.(2)
CT scan shows localized dilation of the bronchi predominantly in the upper lobes indicating bronchiectasis (indicated by the purple and black arrow) There is also diffuse tree-in-bud opacities, an opacity is a lung abnormality with increased density (indicated by the large purple arrow). The ‘tree-in-bud’ sign demonstrates some degree of airway obstructions by infection or secretions.(2) Studies have shown that the tree-in-bud pattern is caused by the borders of the branches of the peripheral airways becoming visible (usually they are invisible) which is often the result of the bronchioles becoming impacted with mucus, pus or fluid. The thickened and dilated walls of the bronchi combined with inflammation in Cystic Fibrosis can also make the bronchioles more visible.
Cystic Fibrosis is a genetically inherited disease that affects several areas of the body particularly all exocrine tissue; the lungs, pancreas, liver, intestines and reproductive tract. The normal transport of chloride and sodium around the body is disrupted in Cystic Fibrosis which results in thick, viscous secretions that can cause damage to the body’s organs and to an increased salt content in sweat gland secretions,(3) this being one of the diagnostic markers. The disorder’s most common symptoms include progressive damage to the respiratory system, in 90 percent of cystic fibrosis cases, the airways are affected(4)combined with chronic digestive system problems. Cystic Fibrosis can be diagnosed at any time but most commonly affects infants, children and young adults. An estimated 70,000 children and adults worldwide have Cystic Fibrosis (30,000 cases from the United States alone).
1. Friedman PJ. Chest radiographic findings in the adult with cystic fibrosis. Semin Roentgenol. Apr 1987;22(2):114-24.
2. Reiff DB, Wells AU, Carr DH. CT findings in bronchiectasis: limited value in distinguishing between idiopathic and specific types. AJR Am J Roentgenol. Aug 1995;165(2):261-7.
3. Tager AM, Wu J, Vermeulen MW. The effect of chloride concentration on human neutrophil functions: potential relevance to cystic fibrosis. Am J Respir Cell Mol Biol. Oct 1998;19(4):643-52.
4. 1 Cystic Fibrosis Foundation. Patient Registry 2007 Annual Report. September 2009. Available at http://www.