Purpose: To assess arterial spin labeling (ASL) and diffusion-weighted imaging (DWI) in the differentiation of metastatic from reactive lymph nodes (LNs) in head and neck squamous cell carcinoma (HNSCC).
Materials and methods: Retrospective analysis of 113 LNs in 43 patients with HNSCC underwent ASL and DWI of the neck. The tumor blood flow (TBF) and apparent diffusion coefficient (ADC) of the cervical LNs were calculated. The final diagnosis of metastatic (n = 82) and reactive (n = 31) was proved with the pathological examination.
Results: The TBF of metastatic LNs (58.8 ± 10.2, 58.6 ± 8.5 mL/100 g/min) was significantly higher (p = 0.001) than the reactive LNs (23.2 ± 10.3, 28.2 ± 16.7 mL/100 g/min) for both observers, respectively. The ADC of metastatic LN (1.12 ± 0.07, 1.21 ± 0.07 × 10-3mm2/s) was significantly lower (p = 0.001) than reactive LN (1.41 ± 0.09, 1.44 ± 0.14 × 10-3mm2/s) for both observers, respectively. The threshold of TBF (> 39.5, 40.5 mL/100 g/min), ADC (≥ 1.31, 1.30 X10-3mm2/s) and combined parameters for both observers, respectively, used for differentiating metastatic from reactive LNs revealed an area under the curve of (0.94, 0.945), (0.90, 0.931), and (0.98, 0.989), an accuracy of (88.6%, 80.5%), (80.0%, 88.5%), and (94.3%, 98.2), respectively.
Conclusion: Combined TBF and ADC are non-invasive imaging parameters that can play a role in differentiation metastatic from reactive LNs in patients with HNSCC.
Keywords: Arterial spin; Cancer; Diffusion; Head; MR imaging; Neck; Perfusion.