Percutaneous transhepatic intraductal biliary sonography for lymph node staging at 12.5 MHz in malignant bile duct obstruction: work in progress.

Abstract

To assess the value of intraductal ultrasound (US) for lymph node staging in malignant biliary obstruction. Eighteen patients with malignant extrahepatic obstruction were imaged during percutaneous bile duct drainage with a mechanically rotating US transducer at 12.5 MHz. Detectable lymph nodes were classified as malignant when two of three criteria (hypoechoic, rounded, conspicuous margins) were fulfilled. The results were compared with histopathological data in 8 patients and follow-up CT findings in 10 patients. In 15 of 18 patients (83%) malignant lymph node involvement was suspected at intraductal US and in 5 of 18 patients (28%) during CT. Histopathological investigation after operation (n = 8) and follow-up CT studies (n = 10) revealed the presence of malignant nodal involvement in 13 of 18 (72%) patients. The sensitivity, specificity, and accuracy of transhepatic intraductal biliary US in determining merely the presence or absence of malignant lymph nodes without specific topographic assignment were 92%, 40%, and 78%, respectively. These preliminary results suggest that intraductal US may develop into a promising adjunctive modality during percutaneous bile duct drainage in patients with suspected malignant regional lymph node involvement.