Lymph nodes in the head and neck cancer: would diffusion-weighted magnetic resonance imaging solve the diagnostic dilemma?

Head and neck cancer has been labeled as the fifth most common cancer. Lymph node (LN) metastases were reported as the most important predatory factor for diagnosis and selection of suitable treatment. Diffusion-weighted (DW) magnetic resonance (MR) imaging is a very important tool that gives quantitative data in several compartments. This work aims to evaluate the diagnostic value of diffusion-weighted as a part of the magnetic resonance imaging in patients with head and neck cancer to allow differentiation of lymph nodes, cancer staging, assessment of recurrence, and evaluation of the effects of oncologic therapy. The size of pathologically proven benign LNs ranged from 1 to 3 cm (1.71 ± 0.724) and malignant LNs ranged from 1.1 to 5.6 cm (2.54 ± 0.92) (P = 0.0103). The ADC value for benign LNs ranged from 1.26 × 10−3 to 2.49 × 10−3 (mean 1.98 × 10−3 ± 0.32 × 10−3), and malignant LNs from 0.608 × 10−3 to 2.1 × 10−3 (mean 0.971 × 10−3 ± 0.305 × 10−3) (P < 0.001) with sensitivity and a specificity of 94% and 100% respectively. The ADC value for metastatic LNs ranged from 0.70 × 10−3 to 2.10 × 10−3 (1.08 × 10−3 ± 0.31 × 10−3) while lymphomatous nodes ranged 0.608 × 10−3 to 1.16 × 10−3 (0.78 × 10−3 ± 0.17 × 10−3). In this study, a significant statistical difference was also observed between the ADC value of the SCC and lymphomatous LN (P = 0.0034) with sensitivity and a specificity of 90% and 75% respectively. Diffusion-weighted MR imaging is an effective assist in differentiating benign and malignant lymph nodes. It acts as an indicator for recovery or recurrence after chemotherapy and radiotherapy.