Prediction of Lymph Node Metastasis in Non-Small Cell Lung Cancer and Its Correlation with Ki67 Expression: A Comparative Study between Intravoxel Incoherent Motion Imaging and 18F-FDG PET

Background: Integrated positron emission tomography/magnetic resonance (PET/MR) may have the potential to evaluate lymph node metastasis status and Ki-67 proliferation index in patients with non-small cell lung cancer. Methods: This study enrolled 92 pathologically confirmed NSCLC patients who underwent preoperative integrated PET/MRI. Quantitative analysis was performed for PET metabolic parameters (SUVmax, MTV, TLG) and IVIM parameters (ADC, D, D*, f, DDC). The predictive performance of each parameter for LNM was assessed using receiver operating characteristic (ROC) curve analysis, and a multivariate logistic regression model was constructed to establish the optimal combined predictive model. Spearman correlation analysis was used to explore the relationship between imaging parameters and Ki-67 expression. Results: LNM prediction: The LNM-positive group exhibited lower ADC, D, and DDC (all P < 0.05) compared to the LNM-negative group. Multivariate analysis identified MTV and DDC as independent predictors of LNM. The combined model (MTV + DDC) achieved an AUC of 0.821 (sensitivity 79.49%, specificity 73.59%), significantly outperforming individual parameters (P < 0.05). Ki-67 correlation: SUVmax, MTV, and TLG showed positive correlations with Ki-67 (r= 0.232–0.300, P < 0.05), while ADC and D values exhibited negative correlations (r= −0.327 to −0.240, P < 0.05). No significant association was observed between D*, f, and Ki-67 (P > 0.05). Conclusion: Integrated PET/MRI, by combining metabolic (MTV) and diffusion (DDC) parameters, significantly improves the predictive accuracy for LNM in NSCLC. Additionally, metabolic and select IVIM parameters correlate with Ki-67 expression.