Acoustic radiation force impulse imaging for reactive and malignant/metastatic cervical lymph nodes

The aim of this study was to compare lymph node stiffness using acoustic radiation force impulse (ARFI) imaging in patients with cervical lymph node swelling. Forty-two cervical lymph nodes (reactive, n = 22; metastatic, n = 20) from 19 patients (13 men, 6 women; mean age, 63.68 ± 14.9 y; range, 23-85 y) were examined between September 2011 and March 2012. The shear wave velocity (SWV, m/s) of each lymph node was evaluated by ARFI imaging. SWV of reactive lymph nodes was 1.52 ± 0.48 m/s, and that of metastatic/malignant lymph nodes was 2.46 ± 0.75 m/s. A SWV > 1.9 m/s was very useful metastatic lymph node classification, with 95.0% specificity, 81.8% sensitivity and 88.0% overall accuracy. The area under the receiver operating characteristic curve was 0.923 (95% confidence interval, 0.842-1.000). ARFI imaging can be useful in the differentiation of reactive and malignant/metastatic cervical lymph nodes.