INTRODUCTION: Sphincter of Oddi (SO) manometry is considered to be the gold standard for assessing patients for SOD. However, manometry is technically demanding and has definite risks, A previous study reported on the ultrasound characteristics of the normal SO muscle (SOM) using CBUSP (Itoh, et al. I Ultra Med, 1994;13:679-84). We present our pilot data experience using a CBUSP to evaluate the SO compared to results of SO manometry. AIM OF STUDY; To evaluate the role of a CBUSP in determining the presence of SOD during ERCP based on ultrasound evaluation of the SOM layers. METHODS: To date, 5 pts have been enrolled in this ongoing study. The endosonographer was blinded to the manometry results. After completion of manometry, a 6.2 Fr, 12 MHz monorail (over the wire) CBUSP probe (Microvasive, Natick, MA) was inserted into the assessory port of the duodenoscope and advanced into the mid-CBD fluoroscopically. The CBUSP was then slowly withdrawn into the SO region which is confirmed by ultrasound visualization of the muscle layers. Measurements of the SO were then performed and recorded. We initially measured the SOM to be 0.165 cm in thickness in 3 normal controls. Pts with previous sphincterotomy or obvious biliary pathology on ERCP were excluded from this study. The manometry was considered abnormal if the baseline sphincter pressure was ≥40 mm Hg. Measurement of the SOM was then compared to the results of the SO manometry for each patient. RESULTS: NL SOM ABNL SOM NL SOM ABL SOM NL Mano NL Mano ABNL Mano ABNL Mano n=3 x = 0.166 cm - - n=2 x = 0.373 cm NL = normal, ABNL = abnormal. CONCLUSION : Our early data seems to suggest that CBUSP measurement of the sphincter of Oddi may aid in the diagnosis of SOD. An abnormally thickened SOM as measured by the CBUSP appears to correlate with abnormal SO manometry in the two patients evaluated. Further studies are ongoing with larger numbers of patients.
ASJC Scopus subject areas
- Radiology Nuclear Medicine and imaging