Metastatic and Inflammatory Cervical Lymph Nodes as Analyzed by Contrast-Enhanced Color-Coded Doppler Ultrasonography: Quantitative Dynamic Perfusion Patterns and Histopathologic Correlation

Abstract

Use of contrast-enhanced color-coded Doppler (ultra)sonography (CCDS) in evaluating enlarged lymph nodes has been subject to numerous attempts to define criteria for differentiation between benign and malignant lesions. Evaluation of dynamic perfusion patterns with contrast-enhanced CCDS in cervical lymph nodes offers new possibilities of differential diagnosis. A total of 28 patients with clinically enlarged lymph nodes were included in this study. Contrast-enhanced CCDS was performed on each patient. The color signals from nodes <15 mm in diameter were analyzed with a specialized computer program. Each node was later examined through immunohistochemical staining. Vascularization as shown by unenhanced CCDS was significantly greater in metastatic lymph nodes than in reactively enlarged lymph nodes (8.66% versus 2.81%; p = .01). The maximum vascularization area after contrast injection did not show any significant change (26.61 % versus 28.63%; p = .75). Comparison of values obtained before and after contrast enhancement showed the largest relative increase in vascularization in inflammatory lymph nodes, from a factor of 19.55 to a factor of 10.03 (p = .025). Dynamic values such as contrast enhancement, behavior of dynamic values referred to time, and the evaluated vascularized area did not show any significant difference. The metastatic lymph nodes (5.46 versus 3.33; p = .007) predominantly consisted of large blood vessels. The increased vascularization in the unenhanced CCDS examination of metastatic lymph nodes seems to be associated with the increased number of large blood vessels. An increased vessel density, due to a greater number of total vessels, is related to an inflammatory process. Color Doppler mapping has been proven to depict useful aspects distinguishing benign from malignant lymph nodes of the neck; however, a definitive differentiation between lymph nodes involved with malignancy and inflammatory changes remains difficult.