Purpose: The purpose of this preliminary study was to evaluate the usefulness of power Doppler sonography in differentiating metastatic from nonmetastatic cervical lymph nodes in patients with cancer.
Methods: Histologically proved metastatic (n = 71) and nonmetastatic (n = 220) lymph nodes were examined with power Doppler sonography in 77 patients with head and neck cancer. Power Doppler sonography was assessed for its ability to differentiate metastatic from nonmetastatic lymph nodes.
Results: Power Doppler sonography showed characteristic features of parenchymal blood flow signal in 59 (83%) of the 71 metastatic lymph nodes. By contrast, only four (2%) of the 220 nonmetastatic nodes showed these power Doppler signals. In addition, power Doppler sonography showed high levels of sensitivity (83%) and specificity (98%) in depicting metastatic lymph nodes, which were superior to the values (66% sensitivity and 92% specificity) obtained by applying size criteria (transverse to longitudinal ratio). However, a combination of the two criteria (parenchymal color signal and transverse to longitudinal ratio) improved diagnostic accuracy to 92% sensitivity and 100% specificity.
Conclusion: Our preliminary findings suggest that the power Doppler criteria of no hilar flow, peripheral parenchymal nodal flow, and a transverse to longitudinal ratio of more than 0.65 together constitute a powerful tool for depicting metastatic lymph nodes in patients with cancer.