Cystic fibrosis

Cystic fibrosis (CF) is an autosomal recessive disorder that is characterized by an abnormality of exocrine gland function. Adult patients represent a rapidly growing percentage of the CF population. Pulmonary changes are seen in nearly every case and are the most serious complication of CF. In advanced lung disease, bronchiectasis, emphysematous bullae, and subpleural blebs can frequently develop. Although pulmonary disease is the most common cause of death and morbidity among CF patients, there also can be involvement of other organs, particularly in adults, which show characteristic signs on CT and spiral CT. Pancreatic abnormalities are present in 85–90% of CF patients. The degree of pancreatic involvement varies, ranging from accumulations of mucus in the small ducts to totally plugged ducts, which can cause atrophy of the exocrine glands and progressive fibrosis. Pancreatic dysfunction on CT is demonstrated as fatty replacement and fibrosis of the pancreas. However, there may be scattered foci of pancreatic calcifications that can be detectable on plain radiographs. Hepatobiliary involvement follows the same pattern as pancreatic abnormalities. Bile canaliculi are plugged by mucinous material and when this plugging is of long duration, biliary cirrhosis with diffuse hepatic nodularity may develop. Such severe hepatic involvement is seen in only about 2–5% of patients, although minor hepatic alterations, such as diffuse fatty changes, are fairly common. Hepatobiliary involvement is characterized by hepatic nodularity, compatible with cirrhosis, splenomegaly, and ascites. Complete obstruction of the ileum by meconium occurs in approximately 10% of newborns with CF. Intestinal findings on CT include obstruction, although this is more common in children. These CT signs should be evaluated carefully in adult patients since they may be suggestive of CF. Computed tomography offers unique information about organ involvement (other than pulmonary) that can alter diagnosis and patient management.