LAUSR

Purpose To evaluate the diagnostic performance of the quantitative parameters derived from diffusion-weighted imaging (DWI) and dynamic contrast-enhanced (DCE) MRI in differentiating lacrimal gland pleomorphic adenomas (LGPAs) from lacrimal gland malignant epithelial tumors (LGMETs). Methods Seventy-seven cases with LG epithelial tumors confirmed by histopathology (47 LGPAs and 30 LGMETs) underwent DWI and DCE-MRI. The quantitative parameters including the apparent diffusion coefficient (ADC), the volume transfer constant ( K trans ), the efflux rate constant from the extravascular extracellular space (EES) to blood plasma ( K ep ), and the extravascular extracellular volume fraction ( V e ) were used to differentiate LGPAs from LGMETs. Independent-samples t test was conducted to compare these parameters. The diagnostic performance was evaluated using receiver operating characteristic (ROC) curve analysis. Results Compared with LGPAs, LGMETs had significantly lower ADC value (1.090 ± 0.169mm 2 /s) ( P < 0.001), higher K trans value (0.892 ± 0.517/min) ( P = 0.001), and K ep value (1.300 ± 1.131/min) ( P = 0.002). ADC as a diagnostic index showed a better diagnostic efficacy in predicting malignant tumors (AUC 0.914, sensitivity 90.0%, specificity 85.1%, and accuracy 87.0%) than K trans and K ep alone. The combination of ADC and K trans presented the optimal diagnostic performance for the differentiation (AUC 0.938, sensitivity 93.3%, specificity 87.2%, accuracy 89.6%). Conclusion The quantitative parameters including ADC, K trans , and K ep derived from DWI and DCE-MRI might be potential imaging biomarkers in differentiating LGPAs from LGMETs. The combination of ADC and K trans is superior to other quantitative parameters in distinguishing LGPAs from LGMETs.