Comparative Study of Multi-Model Diffusion Magnetic Resonance Imaging in the Diagnosis of Radiation-Induced Temporal Lobe Injury

Objective To compare the diagnostic value of multiple diffusion magnetic resonance imaging models in radiation-induced temporal lobe injury (temporal lobe necrosis, TLN) and to identify quantitative parameters with optimal diagnostic performance.Materials and Methods Eighty patients with unilateral TLN after radiotherapy for nasopharyngeal carcinoma were retrospectively enrolled. All patients underwent conventional MRI and multi-model diffusion MRI examinations. Apparent diffusion coefficient (ADC), diffusion tensor imaging (DTI), diffusion kurtosis imaging (DKI), mean apparent propagator MRI (MAP-MRI), and neurite orientation dispersion and density imaging (NODDI) models were fitted based on the same diffusion dataset. Differences in diffusion parameters between the affected temporal lobe and the contralateral normal temporal lobe were compared. Receiver operating characteristic (ROC) curve analysis was performed to evaluate the diagnostic performance of each parameter. Results: All diffusion parameters showed statistically significant differences between the affected temporal lobe and the contralateral normal temporal lobe (all P < 0.001). The parameters with the best diagnostic performance were radial kurtosis from DKI, radial diffusivity from DTI, non-Gaussianity anisotropy from MAP-MRI, and intracellular volume fraction from NODDI. The corresponding areas under the ROC curve were significantly higher than that of conventional ADC. Among these parameters, MAP-MRI- and NODDI-derived metrics demonstrated higher specificity and accuracy. Conclusion: Multi-model diffusion MRI can effectively reflect microstructural alterations in radiation-induced temporal lobe injury. MAP-MRI and NODDI models show higher diagnostic value than conventional ADC.