Ultrasound of neck lymph nodes: How to do it and how do they look?

Cervical lymphadenopathy is commonly caused by metastases, lymphoma, tuberculosis and reactive hyperplasia. Before making an accurate diagnosis of pathologic lymph nodes, a clear understanding of the normal appearances of cervical nodes is crucial. Ultrasound examination of cervical lymph nodes is common in routine clinical practice because of its high sensitivity and specificity when combined with ultrasound-guided fine-needle aspiration cytology (FNAC). This article reviews the ultrasound of cervical lymph nodes including classification of the nodes, equipment, scanning technique and sonographic appearances of normal and common abnormal lymph nodes. The sonographic appearance of unusual cervical lymphadenopathy and the value of three-dimensional ultrasound in the volumetric measurements of cervical nodes are also discussed.