Afferent loop syndrome: the role of Tc-99m mebrofenin hepatobiliary scintigraphy.

Afferent loop syndrome is caused by intermittent mechanical obstruction of the afferent loop of a gastrojejunostomy and may present early as an acute type or late as a chronic type. The authors describe two patients who were examined for a history of bilious vomiting after gastrojejunostomy, and who were thought to have afferent loop syndrome (chronic type) based on clinical findings. Results of routine investigations, such as upper gastrointestinal endoscopy, and ultrasonography were inconclusive. Findings from the barium meal follow-through studies were normal in the first patient and revealed a dilated duodenum in the second patient. Tc-99m bromotriethyl-iminodiacetic acid has been used to identify afferent loop obstruction as represented in these studies.