The place of CEUS in distinguishing benign from malignant cervical lymph nodes: a prospective study.

AIMS: The aim of the study was to evaluate the ability of contrast-enhanced ultrasonography (CEUS) compared to gray-scale B-mode and color Doppler ultrasound in differentiate benign versus malign superficial cervical lymph nodes.

MATERIAL AND METHODS: In a prospective study ultrasonography (gray scale, color and spectral Dopller, and CEUS) was performed in 61 patients (33 men, 28 women; mean age of 51.2 years, range: 18-81 years), with cervical lymphadenopathy. The nodes were examined and biopsied or surgically removed. CEUS was performed with 2.4 ml intravenous bolus of contrast agent Sono Vue and the results were registered with a special software.

RESULTS: Of all the nodes, 32 were benign and 29 were malignant (metastases). Solbiati index was higher in benign nodes (2.23 +/- 0.84 vs 1.50 +/- 0.48, p<0.05). Doppler parameters (vessel location, vascular pattern, pedicullum number, resistivity index, and pulsatility index) were significantly lower in benign nodes (p<0.001), and ROC analysis returned excellent results. For CEUS, derived peak intensity (DPI %) was higher in benign nodes (17.72 +/- 5.43 vs 11.76 +/- 4.88, p<0.05); regional blood volume (RBV) was also higher (849.8 +/- 467.1 vs 458.3 +/- 283.3, p<0.05). The time to peak (TTP, s) and area under the curve (AUC, cm2) were similar in both benign and malignant nodes. Enhancement pattern was the most accurate to characterize benign versus malignant nodes. Sensitivity and specificity were higher for DPI, RBV and enhancement pattern from CEUS, according to ROC analysis, compared to gray scale ultrasound, but lower than color Doppler. Analyzing the place of CEUS in lymph node evaluation we found that CEUS is most useful for the evaluation of the lymph nodes with uncertain aspect at gray scale and Doppler evaluation.

CONCLUSIONS: ROC analysis confirmed the higher degree of diagnostic accuracy of CEUS in comparison with conventional techniques for some parameters such as enhancement pattern. Evaluation of nodal perfusion with this method can be helpful in the differentiation of benign from malignant nodes but requires further confirmation.