Abstract
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Introduction: Cervical node metastasis is one of the most important prognostic factors for patients with oral and maxillofacial tumor. Accurate nodal staging is essential to determine an appropriate treatment. This study is to evaluate the value of 18F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) by using visual analysis and the maximum standardized uptake value (SUVmax) in diagnosis of cervical lymph node metastasis of oral and maxillofacial tumor, and to compare with magnetic resonance imaging (MRI). Materials and methods: A retrospective review of ninty-two patients with primary oral and maxillofacial tumor who underwent PET/CT and MRI prior to neck dissection were assessed. Pre-operative PET/CT scans were reviewed by two experienced nuclear medicine physicians and SUVmax of each suspected lymph node documented. Histological results of the neck dissection were considered as gold standard. The diagnostic value of 18F-FDG PET/CT and MRI was evaluated in patients. Furthermore, receiver operating characteristic (ROC) curve analysis of SUVmax of suspected lymph node was performed to distinguish between the metastasis and non- metastasis, and the area under curve (AUC) was obtained. Results: A total of 92 patients including 42 patients with metastatic nodes were evaluated. 119 lymph nodes in 42 patients were diagnosised as metastases and 1949 lymph nodes in 50 patients were benign. The sensitivity, specificity and accuracy by using visual analysis of 18F-FDG PET/CT in 92 patients were 88.1%, 76.0% and 81.5%, respectively; and those in MRI were 59.5%, 84.0% and 75.0%, respectively. The difference of sensitivity was statistically significant (χ2 = 8.868, P < 0.05), and the difference of specificity and accuracy was no statistically significant (χ2 =1.000, 1.150, respectively; P > 0.05). Besides, this study found that SUVmaxof true-positive (TP) nodes was significantly higher than that of false-positive (FP) nodes (t = 5.94, P = 0.000). The sensitivity, specificity and accuracy of 18F-FDG PET/CT in 2068 lymph nodes were 66.4%, 97.9% and 96.1%, respectively. The ROC-AUC of SUVmax was 0.787 (95% CI 0.708-0.866, P = 0.000) and cut-off was 5.04 with a sensitivity of 70.9% and specificity of 82.9%, respectively. Conclusions: 18F-FDG PET/CT is particularly useful in evaluating the nodal staging for oral and maxillofacial tumor, and even more sensitive than MRI. There was a high specificity of SUVmax in evaluating cervical lymph node metastases. Key words: Oral and maxillofacial tumor; cervical lymph node metastasis; 18F-FDG PET/CT; standardized uptake value