Contracted gallbladder: a cause of false-positive hepatobiliary scan in patients with cystic fibrosis.

Gallbladder nonvisualization on hepatobiliary scintigraphy in cystic fibrosis is generally secondary to cystic duct obstruction from inspissated bile, mucus, or gallstones. We report gallbladder nonvisualization on hepatobiliary imaging in two patients with cystic fibrosis who had contracted gallbladders on ultrasonography. Repeat ultrasonography at 6 months revealed persistent gallbladder contraction. A contracted gallbladder therefore is a potential cause of a false-positive hepatobiliary scan which can be treated with conservative management.