Traumatic Bronchobiliary Fistula: Image Correlation with HIDA and SPECT/CT

Objectives: The objective of this presentation is to describe the pathophysiological and diagnostic elements of a traumatic bronchobiliary fistula and its correlation with various imaging modalities, including hepatobiliary (HIDA) scintigraphy and SPECT/CT.

Methods: Hepatobiliary scintigraphy was initially obtained with injection of 4.4 mCi of Tc-99m mebrofenin to assess for extrahepatic biliary leak. These findings were confirmed with SPECT/CT of the lower chest and upper abdomen. Follow up analysis of sputum for any biliary contents, post-radiotracer injection, was obtained using a single static image from the gamma camera.

Results: HIDA images obtained demonstrated normal flow to the liver, with an expected photopenic area on the liver dome correlating with known gunshot wound tract. Gallbladder was not visualized within 60 minutes; however, abnormal accumulation of radiotracer was seen on the dome of the liver. SPECT/CT was obtained for further evaluation and demonstrated abnormal radiotracer accumulation within the gunshot wound tract through the liver, extending to the right lung base. Correlation with physical exam showed leakage of suspected bile to the skin surface in the right posterolateral chest wall. Sputum analysis with the gamma camera demonstrated increased radiotracer activity that confirmed the suspected bronchobiliary fistula. Conclusion: The first documented case of a bronchobiliary fistula was in 1850 in a patient with hydatid cyst disease. Today, the majority of these fistulas are mechanical (bile duct obstruction) or infectious (abscess) in nature. However, bronchobiliary fistulas have been described as a rare and unusual complication of traumatic thoracoabdominal wounds. Clinical symptoms, including biliptysis, are usually sufficient to make the diagnosis. Diagnostic imaging is most often attained regardless to assess the full extent of trauma. CT, MRCP, and ERCP are the most widely used diagnostic methods to assess for bronchobiliary fistulas. CT may be able to show indirect evidence of these fistulas, such as subphrenic fluid collection, diaphragmatic discontinuity, and bronchiectasis. Hepatobiliary scintigraphy, however, is most reliable in detecting even small bronchobiliary fistulas by including information regarding the pathophysiology of bile excretion. SPECT/CT can be used following hepatobiliary scintigraphy to confirm these suspicions. These two methods provide the most practical, non-invasive evaluation into the anatomy and function of the biliary system, including rare pathology, such as traumatic fistula formation.