Background: In sphincter of Oddi dysfunction (SOD), sphincter of Oddi manometry (SOM) predicts the response to sphincterotomy, but is invasive and associated with complications.
Aim: To evaluate the role of secretin-stimulated magnetic resonance cholangiopancreatography (ss-MRCP) in predicting the results of SOM in patients with suspected type II or III SOD.
Methods: MRCP was performed at baseline and at 1, 3, 5 and 7 min after intravenous secretin. SOD was diagnosed when the mean basal sphincter pressure at SOM was >40 mm Hg. Long-term outcome after SOM, with or without endoscopic sphincterotomy, was assessed using an 11-point (0-10) Likert scale.
Results: Of 47 patients (male/female 9/38; mean age 46 years; range 27-69 years) referred for SOM, 27 (57%) had SOD and underwent biliary and/or pancreatic sphincterotomy. ss-MRCP was abnormal in 10/16 (63%) type II and 0/11 type III SOD cases. The diagnostic accuracy of ss-MRCP for SOD types II and III was 73% and 46%, respectively. During a mean follow-up of 31.6 (range 17-44) months, patients with normal SOM and SOD type II experienced a significant reduction in symptoms (mean Likert score 8 vs 4; p = 0.03, and 9 vs 1.6; p = 0.0002, respectively), whereas in patients with SOD type III, there was no improvement in pain scores. All patients with SOD and an abnormal ss-MRCP (n = 12) reported long-term symptom improvement (mean Likert score 9.2 v 1.2, p<0.001).
Conclusions: ss-MRCP is insensitive in predicting abnormal manometry in patients with suspected type III SOD, but is useful in selecting patients with suspected SOD II who are most likely to benefit from endotherapy.