Value of quantitative multiparametric MRI in differentiating pleomorphic adenomas from malignant epithelial tumors in lacrimal gland.

Wang, Yongzhe; Song, Liyuan; Guo, Jian; Xian, Junfang

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 (Ktrans), the efflux rate constant from the extravascular extracellular space (EES) to blood plasma (Kep), and the extravascular extracellular volume fraction (Ve) 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 ± 0.169mm2/s) (P < 0.001), higher Ktrans value (0.892 ± 0.517/min) (P = 0.001), and Kep 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 Ktrans and Kep alone. The combination of ADC and Ktrans 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, Ktrans, and Kep derived from DWI and DCE-MRI might be potential imaging biomarkers in differentiating LGPAs from LGMETs. The combination of ADC and Ktrans is superior to other quantitative parameters in distinguishing LGPAs from LGMETs.