Diffusion-Weighted Imaging in Head and Neck Cancer: Technique, Limitations, and Applications.

Diffusion-weighted imaging (DWI) of the head and neck represents a distinct method of MR imaging with far-ranging applications. Research continues to hone the capabilities of DWI in characterization, prediction, monitoring, assessing response to treatment, and detecting posttreatment changes and recurrent tumors. Pretreatment apparent diffusion coefficient (ADC) values can suggest the likelihood of response to treatment. DWI-obtained ADC values are able to look beyond the anatomy in posttreatment tumor beds and metastatic lymph nodes to evaluate for tumor recurrence. Further research should include large-scale, multiinstitutional studies to provide standardized ADC cutoff values for more widespread use.