Sphincter of Oddi dysfunction: two case reports and a review of the literature.

Sphincter of Oddi dysfunction is an underdiagnosed but important clinical condition. It should be considered in the differential diagnosis of biliary pain when the gallbladder sonogram shows no evidence of gallbladder disease. Hepatobiliary scanning (Tc-99m dimethyl iminodiacetic acid) may provide valuable information in the evaluation of these patients and may be helpful in monitoring response to treatment.