Nuclear Medicine Scintigraphy (NMS) Results Predict Symptom Resolution After Sphincterotomy in Patients With Sphincter of Oddi Dysfunction (SOD)

Abstract

Introduction: Endoscopic retrograde cholangiopancreatography (ERCP) with sphincter of Oddi manometry is the gold standard test for diagnosis of SOD, but is associated with high risk of complications. A nuclear medicine scintigraphy (NMS) test is a safe, non-invasive, alternative test for evaluation of biliary SOD. ERCP with biliary sphincterotomy is the standard treatment for SOD. Our study aim is to assess the utility of NMS results in predicting symptom resolution after sphincterotomy in patients with SOD type 2. Methods: In this retrospective cohort study, patients who underwent both NMS and sphincterotomy for SOD type 2 between 2007 and 2014 were included. Patient demographics, clinical symptoms, laboratory tests, imaging studies, endoscopic ultrasound, and ERCP findings were recorded. The NMS results were reported on a scoring system ranging from 0 to 12. The symptom resolution after sphincterotomy was stratified into “no response,” “partial response,” or “complete response.” We compared the sphincterotomy response with NMS score results using the analysis of variance (ANOVA) or the Kruskal-Wallis tests for continuous variables and Pearson’s chi-squared tests or Fisher’s exact tests for categorical factors (P<0.05 for significance). The results were adjusted for age, sex, gender, history of smoking, and alcohol use using logistic regression analysis. We used SAS version 9.2 soft ware for the analysis. Results: A total of 30 patients with SOD type 2 met the inclusion criteria. Average age was 47 years and 87% (n=26) were female. During a mean follow-up of 20.6 months, none of the patients achieved complete response, while 57% (n=17) patients had partial response after sphincterotomy. Subjects with partial response were more likely to have abnormal NMS results (p<0.001) as well as higher scores in NMS test (p<0.001). Significance for these findings was maintained even after adjusting for age, gender, and history of smoking or history of alcohol use. A total NMS score of 5 or more would provide sensitivity of 82%, and specificity of 92% (area under the curve=0.93) for prediction of partial symptom resolution after sphincterotomy. Among NMS components, bile duct emptying score (p<0.002), bowel visualization score (p<0.002), and bile duct prominence score (p<0.003) were better predictors compared to peak time score (p=0.073). Conclusion: NMS total score was found to provide accurate prediction of symptom resolution after sphincterotomy. These findings are helpful to stratify patients based on the safe, non-invasive NMS test results that would be benefit from biliary sphincterotomy.