Evaluation of the efficacy of 18F-FDG PET-CT combined with CT in detecting lymph node metastasis in liver cancer

Background This study aims to evaluate the diagnostic efficacy of 18 F-FDG PET-CT imaging and enhanced abdominal CT scans for the preoperative detection of lymph node metastasis in liver cancer. Methods We sought to compare the diagnostic performance of 18F-FDG PET-CT with that of CT and to determine the optimal predictive thresholds for lymph node metastasis, based on the maximum standardized uptake value (SUVmax) and the nodal short-axis diameter. Results The diagnostic efficacy of 18 F-FDG PET-CT, including sensitivity, specificity, and accuracy, was significantly higher than that of CT, with statistically significant differences ( P < 0.05). Both the short diameter of lymph nodes and the SUVmax in the lymph node metastasis group were both greater than those in the non-metastasis group, with statistically significant differences ( P < 0.05). The CT parameter of lymph node short diameter and the 18F-FDG PET-CT parameter of SUVmax were identified as independent predictors of lymph node metastasis in liver cancer and demonstrated a significant positive correlation ( P < 0.001). The area under the receiver operating characteristic curve (ROC) for combined detection was 0.938, with a sensitivity of 92.3%, specificity of 85.3%, and accuracy of 88.3% for diagnosing regional lymph node metastasis in liver cancer. The efficacy of combined detection for diagnosing regional lymph node metastasis in liver cancer was superior to that of individual tests ( P < 0.05), providing valuable clinical guidance for staging, treatment, and prognosis of liver cancer. Conclusion The application of the optimal threshold values can further enhance the diagnostic accuracy of 18 F-FDG PET-CT in detecting regional lymph node metastasis. The proposed criteria for lymph node metastasis were an SUVmax greater than 2.25 or a short diameter exceeding 8.5 mm. This information may assist in the formulation and optimisation of treatment plans for patients with liver cancer.