Quantitative analysis of dynamic contrast-enhanced MRI in conjunction with diffusion weighted imaging for differentiating benign and malignant orbital lymphoproliferative disorder / 中华放射学杂志

ABSTRACT

Objective To evaluate the value of quantitative analysis of dynamic contrast-enhanced MRI (DCE-MRI) and diffusion weighted imaging (DWI) for differentiating malignant from benign orbital lymphoproliferative disorder(OLPD). Methods Forty-three patients with OLPDs(20 patients with benign OLPDs and 23 patients with orbital lymphoma) confirmed by histopathology or clinical follow-up were enrolled in this retrospective study.Quantitative parameters of DCE-MRI including volume transfer constant (Ktrans), flux rate constant (Kep), and extravascular extracellular volume fraction (Ve) and mean apparent diffusion coefficient(ADC)values were obtained. χ2test and t test were used to compare the differences of qualitative and quantitative parameters between two groups. Receiver operating characteristic (ROC) curve analyses were used to evaluate the diagnostic ability of each parameter and its combination. Results Malignant group showed significantly lower mean ADC values and higher Kepvalues than benign group [ADC(0.674±0.126)×10-3mm2/s vs(1.030±0.304)×10-3mm2/s,P<0.001;Kep(1.299±0.566)/min vs(0.787± 0.311)/min, P= 0.001], while no significant differences was found on Ktrans(P= 0.637) and Ve(P= 0.023). ROC analyses results indicated that,a sensitivity of 95.7%,specificity of 80.0% and area under curve(AUC) of 0.896 could be obtained,when using ADC=0.809×10-3mm2/s as the cut-off value.Setting the Kepvalue of 0.863/min as the cut-off value, a sensitivity of 91.3%, specificity of 75.0% and AUC of 0.848 could be obtained. When combination of mean ADC and Kepwas used, optimal diagnostic performance could be obtained (AUC, 0.926;sensitivity, 91.3%;specificity, 90.0%). Conclusion Mean ADC values and Kepare significant variables in predicting malignant OLPDs. Combination of DWI and DCE-MRI can further improve the diagnostic capability in differentiating malignant from benign OLPDs.