Current applicability of duplex Doppler ultrasonography in pancreatic head and biliary malignancies

In most patients with a pancreatic head carcinoma or a cholangiocarcinoma of the liver (Klatskin tumour) US is the first imaging modality. Tumour detection using US can exceed that of CT. For small tumours, endosonography or ERCP is recommended. Enlarged lymph nodes are not a major diagnostic parameter, because a reliable differentiation between reactive and malignant lymph nodes is generally not possible. Very tiny liver and peritoneal metastases are missed by the current imaging modalities including US and only detectable by laparoscopy and/or laparoscopic US. Tumour involvement of the portal venous system is an important determinant for irresectability which can often be assessed by duplex Doppler US obviating invasive or expensive imaging modalities. In pancreatic head carcinoma an abnormal pulsed Doppler signal is highly suspicious for involvement of the portal venous system. However, a normal pulsed Doppler signal does not exclude involvement at all. In Klatskin tumour, Doppler US had an accuracy of 91% compared with surgical findings in predicting portal venous involvement. In most cases of pancreatic head carcinoma or Klatskin tumour, US can assess irresectability. However, assessment of curative resectability in these tumours remains a problem.