Multivariate feature analysis of sonographic findings of metastatic cervical lymph nodes: Contribution of blood flow features revealed by power Doppler sonography for predicting metastasis

BACKGROUND AND PURPOSE: Sonographic criteria of the lymph node have been fo und to be good indicators for metastatic lymph nodes. We determined which s onographic features are most predictive of metastasis in cervical lymph nod es among patients with head and neck cancer, METHODS: Gray-scale and power Doppler sonograms were retrospectively analyz ed in 133 cervical lymph nodes (57 metastatic and 76 reactive nodes) from 5 2 patients with head and neck cancer, The gray-scale sonographic features o f the presence or absence of hilar echoes, parenchymal echogenicity, and sh ort and long axis lengths as well as the power Doppler features of normal h ilar flow and abnormal parenchymal flow were evaluated. Univariate and mult ivariate logistic regression analyses were conducted to determine the relat ive value of each sonographic feature. RESULTS: At univariate analysis, all sonographic features assessed were fou nd to be important. Multivariate analysis, however, suggested that the pres ence or absence of hilar echoes, increases in short axis length, and the pr esence of normal hilar flow were the only sonographic features that were pr edictive of reactive (presence of hilar echoes and hilar flow) and metastat ic (increases in short axis length) lymph nodes, Although multivariate anal ysis did not indicate any significant contribution of the color-flow criter ia for predicting metastatic nodes, the color-flow criteria appeared to imp rove the overall diagnostic accuracy for the less experienced observer. CONCLUSION: The sonographic criteria most predictive of metastatic cervical lymph nodes were absent hilar echoes and increases in short axis length, a s assessed by logistic regression analysis. Compared with these gray-scale criteria, color-flow criteria had fewer predictive advantages.