Can Contrast-Enhanced Ultrasound Distinguish Malignant from Reactive Lymph Nodes in Patients with Head and Neck Cancers?

The purpose of this study was to investigate the utility of contrast-enhanced ultrasound in differentiating benign from malignant cervical lymph nodes in patients with squamous cell carcinoma of the head and neck. A consecutive series of 17 patients with known head and neck malignancy scheduled for neck surgery and lymph node clearance were recruited for contrast-enhanced ultrasound evaluation. Sonographic signal intensity as a function of time, comparing features of time to peak, time to arrival and time to wash-out, was quantified. The selected node was removed surgically and submitted for histology. Contrast-enhanced ultrasound examination had 100% sensitivity and 85.7% specificity for lymph node involvement. Functional analysis revealed contrast peaks significantly earlier in the malignant nodes (mean +/- standard deviation) of 24.14 +/- 2.7 s compared with 29.33 +/- 3.4 s (p = 0.0128). Contrast-enhanced ultrasound holds promise in the detection and characterization of metastatic nodes that would not be diagnosed as abnormal on the basis of conventional ultrasound criteria.