Diagnostic Value of Dynamic 18 F-Fluorodeoxyglucose Positron Emission Tomography-Computed Tomography ( 18 F-FDG PET-CT) in Cervical Lymph Node Metastasis of Nasopharyngeal Cancer

Dynamic F-FDG PET-CT scanning can accurately quantify F-FDG uptake and has been successfully applied in diagnosing and evaluating therapeutic effects in various malignant tumors. There is no conclusion as to whether it can accurately distinguish benign and malignant lymph nodes in nasopharyngeal cancer. The main purpose of this study is to reveal the diagnostic value of dynamic PET-CT in cervical lymph node metastasis of nasopharyngeal cancer through analysis. We first searched for cervical lymph nodes interested in static PET-CT, measured their SUV-Max values, and found the corresponding lymph nodes in magnetic resonance images before and after treatment. The valid or invalid groups were included according to the changes in lymph node size before and after treatment. If the change in the product of the maximum diameter and maximum vertical transverse diameter of the lymph node before and after treatment was greater than or equal to 50%, they would be included in the valid group. If the change was less than 50%, they would be included in the invalid group. Their K values were measured on dynamic PET-CT and compared under different conditions. Then, we conducted a correlation analysis between various factors and K values. Finally, diagnostic tests were conducted to compare the sensitivity and specificity of K and SUV-Max. We included 67 cervical lymph nodes from different regions of 51 nasopharyngeal cancer patients and divided them into valid and invalid groups based on changes before treatment. The valid group included 50 lymph nodes, while the invalid group included 17. There wer significant differences ( < 0.001) between the valid and the invalid groups in SUV-Max, K -Mean, and K -Max values. When the SUV-Max was ≤4.5, there was no significant difference in the K -Mean and K -Max between the two groups ( > 0.05). When the SUV-Max was ≤4.5 and pre-treatment lymph nodes were