【摘要】 目的 探讨眼眶良恶性肿块在不同b值磁共振扩散加权成像（DWI）中表观扩散系数（ADC）值的变化，评价ADC值在眼眶良恶性肿块诊断中的价值。方法 81例眼眶肿块患者，其中良性肿块55例，恶性肿块26例。术前行常规MRI及DWI检查，每次取2个扩散敏感因子即b值=0 s/mm²和/或400、700、1 000 s/mm²,观察和比较不同b值条件下良恶性肿块的ADC值差异，采用ROC曲线评价ADC值的诊断价值。结果 3组b值下，眼眶良性肿块ADC值分别为（1.56±0.35）×10^-3mm²/s、（1.40±0.34）×10^-3mm²/s、（1.30±0.32）×10^-3mm²/s,差异有统计学意义（P<0.01）。恶性肿块ADC值分别为（1.12±0.47）×10^-3mm²/s、（0.92±0.42）×10^-3mm²/s、（0.87±0.40）×10^-3mm²/s,差异无统计学意义（P=0.093）。3组b值的ADC值诊断眼眶良恶性肿块的ROC曲线下面积分别为0.799、0.866、0.867;诊断良恶性肿块的阈值分别为1.05×10^-3mm²/s、0.94×10^-3mm²/s和0.93×10^-3mm²/s,判断眼眶恶性肿块的灵敏度分别为65%、81%、81%,特异度分别为94.5%、91%、85%,阳性预测值分别为85%、80%、72%,阴性预测值分别为85%、91%、90%,正确率分别为85%、87%、84%。结论 b值为700 s/mm²诊断效能较高，DWI ADC值对眼眶良恶性肿块具有辅助诊断价值，可以反映眼眶肿块的扩散特征。更多还原

【Abstract】 Objective To investigate the changes on apparent diffusion coefficient（ADC） of diffusion weighted imaging with different b values and to assess the diagnostic value of ADC for discriminating malignant from benign orbital masses.Methods 81 patients（55 benign orbital masses and 26 malignant orbital masses） were enrolled. These patients underwent serial MR and echo-planar DW imaging examinations of the orbits with b values=0 and/or 400,700,1 000 s/mm². The differences of ADC values under different b values between benign and malignant orbital masses were observed and compared, and diagnosis of ADC values was assessed by the receiver operating characteristic（ROC） curve.Results In three groups, the ADC values of benign orbital masses [（1.56±0.35）×10^-3mm²/s,（1.40±0.34）×10^-3mm²/s and（1.30±0.32）×10^-3mm²/s, respectively] were significantly different（P<0.01）, while the ADC values of malignant orbital masses were not statistically different（P=0.093） [（1.12±0.47）×10^-3mm²/s,（0.92±0.42）×10^-3mm²/s and（0.87±0.40）×10^-3mm²/s, respectively]. The areas under the ROC curve of ADC values were 0.799,0.866 and 0.867,respectively. The threshold values were 1.05×10^-3mm²/s, 0.94×10^-3mm²/s and 0.93×10^-3mm²/s（while sensitivity were 65%,81% and 81%; specificity were 94.5%,91% and 85%; positive predictive values were 85%,80%,72%,negative predictive values were 85%,91%,90%,and accuracy were 85%,87% and 84%,respectively）.Conclusion The b value of 700 s/mm² offered better diagnostic performance. ADC values of diffusion weighted imaging can reflect diffusion characteristics of the orbital masses, as a complementary tool in the differentiation of malignant from benign orbital masses.更多还原