FIG 3. Doppler sonographic features of reactive (A–C) and metastatic (D–F) nodes located at level I (A, D), level II (B, E), and level III+IV (C, F). Arrows indicate normal hilar blood flow.

A, Reactive node (7 mm in short-axis diameter) in 55-year-old man with squamous cell carcinoma of lower gingiva shows normal hilar blood flow.

B, Reactive node (8 mm in short-axis diameter) in 66-year-old man with squamous cell carcinoma of soft palate shows normal hilar blood flow.

C, Reactive node (6 mm in short-axis diameter) in 64-year-old man with squamous cell carcinoma of lower gingiva shows normal hilar blood flow.

D, Absence of normal hilar blood flow and presence of parenchymal flow in a metastatic node (7 mm in short-axis diameter) in a 48-year-old man with squamous cell carcinoma of the tongue.

E, Absence of normal hilar blood flow and presence of parenchymal flow in a metastatic node (8 mm in short-axis diameter) in a 53-year-old man with squamous cell carcinoma of the hypopharynx.

F, Absence of normal hilar blood flow in a metastatic node (5 mm in short-axis diameter) in a 49-year-old man with squamous cell carcinoma of the upper gingiva.