Clinical Value of Fused PET/MRI for Surgical Planning in Patients With Oral/Oropharyngeal Carcinoma

OBJECTIVES/HYPOTHESIS To evaluate the usefulness of fused positron emission tomography (PET)/magnetic resonance (MR) images for surgical planning in patients with oral/oropharyngeal cancer and suspected mandibular invasion. STUDY DESIGN Individual cohort study. METHODS Eleven of 17 patients with suspected mandibular invasion of squamous cell carcinoma of the lower gingiva, oropharynx, and buccal mucosa who underwent 18F-fluorodeoxyglucose (FDG) PET/computed tomography (CT) and contrast-enhanced MR imaging (MRI) and had fused PET/MR images were enrolled in this study. The area for surgical resection was determined based on the fused images. The usefulness of these images was confirmed by comparing them with the histopathologic findings in the resected tumors. RESULTS Histopathologic evaluation of the surgical specimens revealed that nine of the 11 patients had invasion into the mandible and/or medial pterygoid muscle. All patients had a negative surgical margin. The sensitivity and specificity for detection of mandibular/medial pterygoid muscle invasion was 100%/40% and 83%/100% by fused PET/MRI, respectively, and 100%/20% and 100%/60% by PET/CT, respectively. Interobserver reproducibility between two radiologists/nuclear medicine physicians and two head and neck surgeons showed that the only statistically significant κ values were for PET/MRI. CONCLUSIONS PET/MRI can be easily understood by head and neck surgeons, who are not diagnostic imaging professionals, and can be used when planning the area to be surgically resected in patients with oral/oropharyngeal cancer and clinically suspected mandibular invasion. Considering the expense of a hybrid PET/MRI system, creation of a fused PET/MR image would provide a reasonable and reliable tool for clinical use in these patients. LEVEL OF EVIDENCE 2b Laryngoscope, 130:367-374, 2020.