Imaging of Perineural Spread in Head and Neck Cancer.

Perineural spread (PNS) of tumor is a recognized pattern of metastasis occurring in the head and neck. Imaging plays a critical role in identifying PNS for adequate staging and treatment planning. Understanding the major branches and pathways of cranial nerves V and VII, key anatomic landmarks, interconnections between these nerves, and pearls and pitfalls of PNS imaging can aid in early detection, appropriate therapy, and the best possible chance for cure.