목적: Preoperative detection of contralateral neck metastasis (CNM) leads to proper planning and prognostic prediction in patients with head and neck squamous cell carcinoma (HNSCC). We therefore investigated whether CLM of previously untreated HNSCC is accurately detected by CT/MRI versus 18F-FDG PET-CT and has a prognostic value. 방법:This prospective study was approved by the Institutional Review Board and written informed consent was obtained from all enrolled patients. In total, 128 patients with HNSCC were preoperatively evaluated with 18F-PET/CT and CT/MRI. Histopathological results of neck dissection sampleswere served as the gold standard. McNemars test and logistic regression using generalized estimating equations.was utilized to compare the diagnostic value of 18F-PET/CT and CT/MRI and Cox proportional hazard models were used for assessing the prognostic value of CNM. 결과:Of the 128 patients, 80 (63%) had neck metastasis in 98 sides and 319 levels and 18 (14%) had contralateral neck metastasis. 18FDG PET/CT was significantly more sensitive than CT/MRI at a per-patient (87.3% vs 72.2%, p=0.003), side (86.8% vs 71.4%, p=0.001) and level(77.8% vs 54.7%, p=0.001) basis. On a per-level basis, FDG PET/CT was significantly more sensitive and accurate than CT/MRI in the contralateral (83.6% vs 70.1%, p=0.001 and 88.1% vs 78.5%, p=0.05 respectively) neck. 결론:As a poor prognostic factor, the CNM of HNSCC can be detected by 18F-PET/CT with high sensitivity and accuracy than CT/MRI.