ASSESSMENT OF HEPATIC-ARTERY INVASION BY BILE-DUCT CANCER USING INTRADUCTAL ULTRASONOGRAPHY

Background and Study Aims: This study was performed to clarify the diagnostic accuracy of intraductal ultrasonography (IDUS) in assessing hepatic artery invasion by bile duct cancer. Patients and Methods: Preoperative assessment of hepatic artery invasion was performed by IDUS via a percutaneous tract or the transpapillary route in a total of 22 patients with extrahepatic bile duct cancer. The probes used had a diameter of 1.4, 2.0, 2.4, 2.6, and 3.2 mm, and frequencies of 7.5, 15, 20, and 30 MHz. In the first six cases, IDUS images were analyzed retrospectively with no knowledge of the operative results or of the other imaging tests. In the following 16 cases, the IDUS images were prospectively reviewed prior to surgery without knowledge of the angiographic findings. The diagnostic accuracy of IDUS was compared with angiography in all cases, with the histopathological results in 20 resected cases, and with the intraoperative findings in two cases with only surgical exploration. Results: IDUS was able to demonstrate the right hepatic artery in all cases, and its accuracy in diagnosing right hepatic invasion was 100%. However, IDUS was able to visualize the proper hepatic artery in only four cases (18%), and the left hepatic artery in only three cases (14%), respectively. IDUS could not visualize the area outside of the hepatoduodenal ligament, because of its low penetration depth. Conclusions: IDUS proved useful for assessing the extension of bile duct cancer invasion into the right hepatic artery. However, IDUS did not sufficiently demonstrate the proper hepatic artery and the left hepatic artery for diagnosing vascular involvement.