Application of contrast-enhanced ultrasound in differential diagnosis of cervical lymph nodes

Abstract

Objective To evaluate the ability of contrast-enhanced ultrasonography (CEUS) in differentiate reactive lymph node, metastatic lymph node and lymphoma. Methods In a prospective study CEUS was performed in 129 patients with cervical lymph node enlargement. The entire process were recorded and preserved in DICOM format. The results were registered with Sonoliver. The receiver operating characteristic curve (ROC curve) analysis was performed to find the corresponding cutoff values. The selected node was removed surgically and submitted for histology. Results Of all the nodes, 26 were reactive nodes, 85 were metastases and 18 were lymphoma. Enhancement pattern was the most accurate way to characterize lymph nodes. The enhancement pattern of reactive lymph nodes was homogeneous and most of them were enhanced by lymphatic type while the metastatic lymph nodes were inhomogeneously enhanced or weakly enhanced by peripheral type. Lymph node lymphoma usually had no fixed enhancement pattern.Arrive time (AT), rise time (RT), time to peak (TTP), mean transit time (mTT), maximum intensity(IMAX), under the curve (AUC), rising slope(Kup), semi descending slope(Kdown) and perfusion index (PI) were significantly different in the three groups(P 0.05). When TTP≥7.74 s, mTT≥26.54 s, metastatic lymph nodes were considered. When RT≥4.62 s, TTP≥7.74 s, mTT≥28.32 s, reactive lymph nodes were not considered. Conclusions Dynamic contrast-enhanced ultrasound image and enhancement pattern can distinguish neck lymph nodes while the optimal cut-off point time of the time-intensity curve parameters can further contribute to the identification of lymph nodes. Key words: Contrast-enhanced ultrasound; Lymph nodes; Diagnosis, differential