TRANSPAPILLARY BILIARY SONOGRAPHY WITH A MICROSCANNER

Abstract

We performed transpapillary biliary sonography (TPBS) with a microscanner devel-oped by Aloka Co. Ltd., and the results of which are herein reported. The microscanner applied in this study was a mechanical radial scanner with a frequency of 20 MHz and a diameter of six Fr. Due to its small size, it was possible to insert it into the bile duct through the channel of a duodenoscope. The sixteen cases, consisting of six cases of choledocholithiasis treated by endoscopic sphincterotomy (EST), three cases of bile duct cancer, two cases of gallbladder cancer, one case of cholecystolithiasis, three cases of pancreatic cancer, and two cases of pancreatolithiasis, underwent TPBS. All the cases were treated with EST prior to TPBS. Insertion of the microscanner into the bile duct and recording of the ultrasonogram of the bile duct wall was achieved in all the 16 cases. The wall was demonstrated to be a two-layer structure fundamentally with a hypoechoic layer and a hyperechoic layer from the inside. The thickness of the hypoechoic layer and the total thickness as measured on the ultrasonogram was 0.4 to 0.9 mm (mean, 0.7) and 0.9 to 1.7 (mean, 1.4), respectively. The periampullary structure, including the muscle of Oddi and the proper muscle layer of the duodenum, was clearly demonstrated by TPBS. No significant complications occurred following this examination from the viewpoints of serum amylase level and subjective symptoms. It is expected that TPBS will provide much information, which is difficult to obtain with other modalities, on the wall of the bile duct and on the periampullary structure.