Utility of MRI diffusion techniques in the evaluation of tumors of the head and neck.

The use of diffusion-weighted imaging in the head and neck is an increasingly used technique that requires adaptation of the acquisition parameters. Parallel imaging and emerging techniques such as IVIM are playing a new role. The main indications for performing DWI are tissue characterization, nodal staging and therapy monitoring. Lower apparent diffusion coefficients have been reported in this region for malignant lesions such as SCC, lymphoma and metastatic lymph node, as opposed to higher ADC in benign lesions and lymph nodes. Follow-up and early response to treatment are reflected in an ADC increase in both primary tumor and nodal metastasis.