Correlation between sphincter of Oddi manometry and intraductal ultrasound morphology in patients with suspected sphincter of Oddi dysfunction.

Abstract

Intraductal ultrasonography (IDUS) makes it possible to study sphincter of Oddi morphology during endoscopy. Two recent IDUS studies have described the sphincter of Oddi as a circumferential hypoechoic layer in the papilla, but there have as yet been few published data from patients with suspected sphincter of Oddi pathology. Twenty-one consecutive patients with suspected biliary sphincter of Oddi dysfunction (seven men, 14 women; age 54 +/- 17 years) were enrolled in the study. Endoscopic sphincter of Oddi manometry was carried out using a 4-Fr electronic microtransducer device. After this, a wire-guided 6-Fr ultrasound catheter was placed in the common bile duct (CBD), and IDUS was carried out while the ultrasound catheter was being withdrawn from the CBD toward the duodenum. Sphincter of Oddi manometry and IDUS were carried out successfully in 18 of the 21 patients. Sphincter of Oddi manometry revealed sphincter of Oddi hypertension (baseline pressure > 35 mmHg) in eight patients. The mean sphincter of Oddi baseline pressure was 32 +/- 17 mmHg, and the mean phasic sphincter of Oddi pressure was 132 +/- 31 mmHg. During IDUS, a circumferential hypoechoic layer was clearly delineated in all patients. There was a significant correlation between the manometrically determined length of the sphincter of Oddi (8 +/- 2 mm) and the thickness of the hypoechoic layer (6 +/- 2 mm) as assessed by IDUS (r = 0.66, P < 0.001). However, no correlation was found between the baseline or phasic sphincter of Oddi pressures and the thickness of the hypoechoic layer. Accordingly, IDUS did not allow identification of patients with sphincter of Oddi hypertension. Mild pancreatitis was observed in one of the 18 patients (6 %). The circumferential hypoechoic layer of the papilla visualized by IDUS is the ultrasonographic correlate of the sphincter of Oddi. IDUS of the papilla is technically feasible and safe in patients with suspected sphincter of Oddi dysfunction. IDUS may provide additional information at the sphincter of Oddi level, but cannot be used as a substitute for sphincter of Oddi manometry.