Squamous Cell Carcinoma: PET/CT and PET/MRI of the Pretreatment and Post-Treatment Neck.

The incidence of head and neck cancer continues to rise annually, most commonly squamous cell carcinoma (SCCa). Advances in imaging techniques have improved diagnostic accuracy with important ramifications for initial staging and post-treatment surveillance. FDG-PET/CT and, more recently, FDG-PET/MRI have revolutionized the staging and surveillance of head and neck SCCa. We detail the diagnostic role of FDG-PET/CT and FDG-PET/MRI of SCCa at the different head and neck subsites, highlighting their role in identifying the primary tumor extent, regional nodal metastases, and distant metastatic disease in the pretreatment and post-treatment setting, as well as implications for staging, treatment, and prognosis.