Lymph node metastasis in head and neck squamous carcinoma: Efficacy of intravoxel incoherent motion magnetic resonance imaging for the differential diagnosis.

PURPOSE: To evaluate the value of pure molecular diffusion(D), perfusion-related diffusion (D*), perfusion fraction (f) and apparent diffusion coefficient (ADC) based on intravoxel incoherent motion (IVIM) theory for differential diagnosis of metastatic lymph nodes (LNs) in head and neck squamous cell carcinoma(HNSCC).

MATERIALS AND METHODS: 29 patients with HNSCC and 20 patients with lymph node hyperplasia (LNH) were enrolled in this retrospective study, underwent magnetic resonance (MR) examination. IVIM Diffusion-weighted imaging (IVIM-DWI) was performed with 13 b values. D, D*, f and ADC values were compared between two groups. The diagnostic value of ADC, D, D* and D·D* value were evaluated by Receiver operating characteristic (ROC) curve. Two radiologists measured D, D*, f and ADC values independently.

RESULTS: 33 malignant LNs in HNSCC group and 22 benign LNs in LNH group (minimum diameter, ≥5mm) were successfully examined, ADC(P<0.05), D (P<0.01) and f (P<0.01) were significantly lower in malignant LNs than that in benign LNs, whereas D* was significantly higher (P<0.01). The area under the ROC curve (AUC) for D·D* was 0.983 and was larger than that for D* (0.952), D (0.78) and ADC (0.67).

CONCLUSION: Our results indicate that IVIM DWI is feasible in the diagnosis of LN metastasis. D was significantly decreased in malignant LNs reflected increased nuclear-to-cytoplasmic ratio tissue, and D* was significantly increased reflected increased blood vessel generation and parenchymal perfusion in malignant LNs.