Background: Sphincter of Oddi dysfunction (SOD) afflicts approximately 1% to 5% of patients after cholecystectomy. The diagnostic standard for SOD is sphincter of Oddi manometry (SOM), a technically difficult, invasive test that is frequently complicated by pancreatitis. A sensitive and accurate noninvasive imaging modality is thus needed for the diagnosis of SOD. Quantitative hepatobiliary scintigraphy (HBS) and fatty meal sonography (EMS) are frequently used for this purpose, but results vary. This study compared SOM, HBS, and EMS in the diagnosis of SOD in a large group of patients.
Methods: Three hundred four consecutive patients after cholecystectomy (38 men, 266 women, age 17-72 years) suspected to have SOD were evaluated by SOM, FMS, and HBS. SOM was considered abnormal if any of the following were observed: (1) increased basal pressure (greater than 40 mm Hg), (2) increased phasic activity with amplitude greater than 350 mm Hg, (3) frequency of contractions greater than 8 per minute, (4) greater than 50% of propagation sequences retrograde, and (5) paradoxical response to cholecystokinin. FMS was considered abnormal if ductal dilation was greater than 2 mm at 45 minutes after fatty meal ingestion. Quantitative HBS was performed with sequential images obtained every 5 minutes for 90 minutes to monitor excretion of the radionuclide. Time-to-peak, halftime, and downslope were calculated according to predetermined ranges.
Results: A diagnosis of SOD was made in 73 patients (24%) by using SOM as the reference standard. HBS was abnormal in 86 whereas EMS was abnormal in 22 patients. A true-positive result was obtained in 15 patients by EMS and 36 patients with HBS. EMS and HBS gave false-positive results, respectively, in 7 and 50 patients. Sensitivity of EMS was 21% and for HBS 49%, whereas specificities were 97% and 78%, respectively. EMS, HBS, or both were abnormal in 90% of patients with Geenen-Hogan Type I SOD, 50% with Type II, and 44% of Type III. Of the 73 patients who underwent sphincterotomy, 40 had a long-term response. Of those with SOD, 11 of 13 patients (85%) with an abnormal HBS and EMS had a good long-term response.
Conclusions: In this series, the largest reported to date, correlation of FMS and HBS with SOM in the diagnosis of SOD was poor. When HBS and EMS are used together, a slight increase in sensitivity can be expected. The accuracy of EMS and HBS in the diagnosis of SOD decreases across the spectrum from Type I to Type III SOD. EMS and HBS, nonetheless, may by of assistance in predicting long-term response to endoscopic sphincterotomy in patients with elevated sphincter of Oddi basal pressure.