The ADC value of parenchyma and necrosis in cervical lymphadenopathy: differential diagnostic value

Abstract

Objective To evaluate the apparent diffusion coefficient (ADC) of parenehyma and necrosis in distinguishing among metastatic lymph nodes, lymphoma and tuberculous lymph nodes. Methods Thirty-six patients with cervical lymph nodes metastasis from the head and neck squamous cell carcinomas,19 patients with lymphoma and 23 patients with lymph nodes tuberculosis underwent diffusion-weighted imaging. The ADC values were measured and compared in parenchyma and necrosis of 177 lymph nodes confirmed by histopathology (n = 114) and clinical follow-up (n = 63). The means between two groups were compared by t-test, and one-way analysis of variance (one-way ANOVA) was used to analyze the data among three or more groups. Results The mean ADC values of parenchyma in metastatic nodes, lymphoma and tuberculous nodes were (0.93±0.16) × 10-3mm2/s, (0.64±0.13) × 10-3mm2/s and (1.01±0.11) ×10 -3 mm2/s respectively (F = 82.928, P < 0.01) ; the ADC values of necrosis in metastatic and tuberculous nodes were (2.02 ± 0. 36) × 10-3 mm2/s and (1.25 ± 0.15) × 10-3 mm2/s respectively (t = 12.045, P <0.01). An ADC value of parenchyma lower than or equal to 0.77 × 10 -3mm2/s was used as the threshold for lymphoma, with a sensitivity 83% and specificity of 89%. An ADC value of necrotic area greater than or equal to 1.60 × 103mm2/s was used as the threshold for metastatic nodes, with a sensitivity of 88% and specificity of 100%. Conclusion The ADC value of lymph nodes, especially for their internal necrotic areas, can help judge the nature of the cervical lymph nodes. Key words: Lymph nodes; Head neck neoplasms; Diffusion magnetic resonance imaging