Recent advances in PET/MR imaging for head and neck tumors: a systematic review of the last three years.

Purpose: This systematic review addresses the clinical relevance of PET/MR in patients with head and neck (HN) tumors, highlighting studies conducted over the last three years to provide an updated perspective on integrating a hybrid PET/MR scan into different clinical scenarios.

Methods: We employed a search algorithm, combining terms ("PET/MR" OR ("PET" AND ("MR" OR "MRI")) OR "PET/MRI" OR "PET-MR" OR "PET-MRI" OR ("PET" AND "magnetic")) AND ("head" AND "neck"). Studies written in English and published throughout 2021, 2022 and 2023 up to November 15th were considered if were focused on: suspected HN tumors; confirmed HN tumors before surgery/radiotherapy/chemotherapy; HN tumor recurrence or therapy response assessment. Reviews, editorials or letters, case report/series or any other original unrelated studies to the topics were excluded.

Results: Twenty out of 169 studies were deemed eligible. The HN tumor cohorts included sinonasal tumors, nasopharyngeal carcinoma and tumors in the oropharynx, oral cavity, hypopharynx and larynx, mostly of squamous cell carcinoma histology. Sixteen out of 20 articles focused on initial staging, including prognostic information before primary treatment, whereas 4/20 articles explored the clinical significance of PET/MR in restaging settings or other clinical purposes.

Conclusion: This review consolidates previous findings by showing the relationship between morphology, metabolism, cellularity, and perfusion in HN tumors. Metrics provided by PET/MR are able to predict the histologic grade of HN tumors, EGFR status and patient outcome. PET/MR demonstrates high diagnostic performance for detecting locoregional tumor recurrence, distant metastases and second primary cancers.