Diffusion-weighted magnetic resonance imaging of head and neck squamous cell carcinomas

Objective: To evaluate whether diffusion-weighted imaging (DWI) is a reliable technique to quantify microstructural differences between head and neck squamous cell carcinomas (SCC) and tumour-free soft tissue. Materials and methods: DWI was obtained from 20 patients with histologically proven, untreated head and neck SCC. DWI was acquired using a diffusion-weighted, navigated echo-planar imaging sequence with a maximum b-value of 800 s/mm2. For an objective assessment of image quality, the signal-to-noise ratio (SNR) was calculated. Microstructural differences between vital tumour tissue and tumour-free soft tissue were quantified by calculating the apparent-diffusion-coefficients (ADC) on a pixel by pixel method. Results: Echo-planar DWI provided good image quality in all patients (mean SNR 18.4). The mean ADC of SCC, (0.64 ± 0.28 x 10-3 mm2/s), was significantly (P < 0.0001) lower than that of the tumour-free soft tissue, (2.51 ± 0.82 x 10-3 mm2/s). Conclusion: DWI is a reliable diagnostic tool to quantify the microstructural differences between vital tumour tissue and tumour-free soft tissue in patients with head and neck SCC