Gallstone ileus:: increased diagnostic sensitivity by combining plain film and ultrasound

Background: Gallstone ileus is an uncommon cause of mechanical obstruction. Its high mortality rate can be reduced with earlier diagnosis and treatment. We wanted to determine whether ultrasound (US) performed after plain film increases the sensitivity for the preoperative diagnosis. Methods: We performed a 5-year retrospective analysis of radiologic and sonographic results of 23 patients who had surgery because of gallstone ileus. Results: Rigler's triad was identified by plain abdominal film in two patients (9%) and by US in 16 patients (69%). Plain abdominal film contributed to a definitive diagnosis in four cases and to a probable diagnosis in six cases (sensitivities of 17% for definitive diagnoses and 43% for definitive and probable diagnoses). US confirmed the diagnosis in six cases of probable gallstone ileus and provided the diagnosis in seven of 13 patients without suspected gallstone ileus based on plain abdominal film. The best results were obtained by combining plain film and US findings, with sensitivities of 74% for definitive diagnoses and 96% for definitive plus probable diagnoses. Conclusion: The preoperative diagnosis of gallstone ileus significantly increases by combining plain film and US findings.