ENLARGED CERVICAL LYMPH-NODES AT HELICAL CT

PURPOSE: To evaluate criteria for differentiating malignant versus rea ctive lymph nodes in the head and neck on the basis of findings at hel ical computed tomography (CT). MATERIALS AND METHODS: Helical CT scans were evaluated of 70 consecutive patients (46 men and 24 women, aged 20-78 years [mean, 51 years]) with known head and neck tumors and cerv ical lymph node enlargement. The ratio of the maximal longitudinal to the maximal axial diameter (L/T) was calculated for nodes larger than 8 mm in diameter based on measurements obtained from coronal, paraxial , and sagittal reconstructions. RESULTS: At histologic examination, 96 of 164 nodes were malignant. Of these, 94 of 96 nodes had an L/T of l ess than 2 (sensitivity, 97%; specificity, 97%; accuracy, 97% for mali gnancy). Minimal diameter was more than 8 mm in 83 of 96 nodes (sensit ivity, 87%; specificity, 89%; accuracy 88% for malignancy). Low-attenu ation centers and rim enhancement were seen in 75 of 96 nodes (sensiti vity, 78%; specificity, 100%; accuracy, 86% for malignancy). CONCLUSIO N: The L/T at helical CT provide an accurate assessment of reactive ve rsus malignant nodes in the head and neck.