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

Abstract 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.