Diagnostic performance of FDG PET/MRI for cervical lymph node metastasis in patients with clinically N0 head and neck cancer

OBJECTIVE: Treatment manage-ment in cases of head and neck squamous cell cancer (HNSCC) that are clinically negative for lymph node metastases (cN0) is still an import-ant topic of discussion. There is increasing in-terest in sensitive imaging modalities that can detect the risk of occult metastases at levels be-low 20%. This study aimed to examine the effica-cy of integrated positron emission tomography (PET)/magnetic resonance imaging (MRI) in de-termining neck nodal metastasis status in cN0 patients with HNSCC.PATIENTS AND METHODS: In this retro-spective study, 44 patients who underwent neck dissection with the diagnosis of HNSCC be-tween January 2018 and August 2020 were an-alyzed. Clinical examinations, including ultra-sonography, were performed to identify cervi-cal metastases in HNSCC patients with preoper-ative cN0. A nuclear medicine specialist visual-ly evaluated the MRI, PET, and PET/MRI results.RESULTS: Histopathologically, 86.4% of pa-tients were classified as N0. According to the his-topathological results, MRI showed 50% sensitiv-ity, 89.5% specificity, 91.8% negative predictive value (NPV), 42.8% positive predictive value (PPV) and 84% accuracy, while PET showed 83.3% sen-sitivity, 68.4% specificity, 96.2% NPV, 29.4% PPV and 70.4% accuracy. PET/MRI was more success-ful in distinguishing pathological N0 and N+ pa-tients (83.3% sensitivity, 92.1% specificity, 97.2% NPV, 62.5% PPV and 90.9% accuracy).CONCLUSIONS: PET/MRI is more sensitive and has a higher NPV compared to MRI alone, while its sensitivity was found to be compara-ble to that of PET. In addition, with its ability to detect pathological N0 patients, PET/MRI may significantly decrease the number of unneces-sary neck dissections.