ASSESSMENT OF PORTAL-VEIN INVASION BY BILE-DUCT CANCER USING INTRADUCTAL ULTRASONOGRAPHY

Background and Study Aims: We recently reported on the contribution of intraductal ultrasonography (IDUS) to the regional staging of bile du ct cancer, and we present here the first detailed study of the value o f IDUS in assessing the portal vein invasion by bile duct cancer. Pati ents and Methods: Preoperative assessment of portal vein invasion was performed by IDUS via a percutaneous tract or via transpapillary route in 18 patients with extrahepatic bile duct cancer, Various probes, wi th diameters of 1,4, 2.0, 2.4, 2.6, and 3.2 mm, and frequencies of 7.5 , 15, 20, and 30 MHz, were used. All patients additionally underwent e ndoscopic ultrasonography (EUS) and angiography. In the first six case s, the IDUS and EUS images were analyzed retrospectively without the k nowledge of operative results or the other imaging tests. In the reman ing 12 cases, IDUS and EUS images were prospectively reviewed prior to surgery, without knowledge of the angiographic findings. The gold sta ndard for the results of IDUS, EUS and angiography was the histopathol ogical findings in 17 resected tumors, and the intraoperative findings in one patient who did not undergo resective surgery. Results: IDUS w as able to demonstrate the portal vein in all cases. Its accuracy in d iagnosing portal vein invasion was 100% for all locations. EUS was use ful in assessing portal vein invasion at the middle and distal bile du ct (the accuracy was 91%), but was not useful in assessing invasion at the proximal bile duct (the accuracy was 57%). Conclusions: IDUS prov ed useful for assessing the extension of cancer invasion into the port al vein, even in proximal bile duct tumors.