PREOPERATIVE STAGING OF EXTRAHEPATIC BILE-DUCT CANCER WITH INTRADUCTAL ULTRASONOGRAPHY

Objective: To evaluate the tumor extension of extrahepatic bile duct c ancer by means of intraductal ultrasonography (IDUS). Methods: IDUS pr eoperatively assessed the tumor extensions in 25 patients with extrahe patic bite duct cancer. The diagnostic accuracy of IDUS was investigat ed by comparison with other diagnostic imaging modalities in all cases and with histopathological findings of resected specimens in 18 eases . Results: IDUS proved useful in assessing the extension of cancer inv asion to the pancreas parenchyma, portal vein, and right hepatic arter y, The limitation of the degree of accuracy, based on the group stagin g criteria, was 68%. IDUS could not assess tumor invasion to the perim uscular loose connective tissue. Therefore, it could not distinguish s tage II from stage I. IDUS could not sufficiently assess epicholedocha l lymph node metastases (differential diagnosis between stages II and III) and could not demonstrate distant metastases (differential diagno sis between stages IVA and IVB) because of the inevitable attenuation of the echo itself. IDUS could assess cases of stage IVA correctly in 8/8 (100%) cases. The combination of PTC/ERC and IDUS could assess the horizontal extension correctly in 13/18 (72%) cases. The combination of PTC/ERC, percutaneous transhepatic cholangioscopy (PTCS), and IDUS assessed the horizontal extension in 14/15 (93%) cases. Conclusion: 1) IDUS, with a high-frequency probe, was very useful for assessing tumo r infiltration in the hepatoduodenal ligament. 2) IDUS could not asses s tumor extension outside of the hepatoduodenal ligament, but conventi onal ultrasonography and angiography could compensate for it. 3) The c ombination of PTC/ERC, PTCS, and IDUS could assess horizontal extensio n correctly.