Ultrasound-guided fine-needle aspiration biopsy of neck nodes. The assessment of nodal involvement in patients with squamous cell carcinoma of the head and neck is still a major diagnostic problem. Although the sensitivity of imaging techniques for detection of neck nodes is gradually improving, the specificity for metastases remains low. Cytologic examination could, theoretically, supply additive information. Computed tomographic-and magnetic resonance-guided aspiration techniques have been described, but these were not efficacious and laborious. In 1984, we developed a technique for ultrasound-guided (UG) fine-needle aspiration biopsy (FNAB). This technique is described herein, and the value of UGFNAB is compared with conventional FNAB. All statistical characteristics of UGFNAB appeared to be superior to conventional FNAB (sensitivity, 98% vs 88%; specificity, 95% vs 82%; positive predictive value, 98% vs 93%; negative predictive value, 95% vs 74%; and accuracy, 97% vs 87%). Furthermore, UGFNAB was characterized by less nondiagnostic aspirations. It is concluded that UGFNAB is a reliable technique for differentiation between benign nodes and cervical lymph node metastases and it may, therefore, contribute to a more accurate assessment of the neck in squamous cell carcinoma of the head and neck. 