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目的 探讨ADC值对眼眶淋巴瘤的诊断价值.方法 对87例眶内肿块患者行常规MR及DWI.87例中男35例、女52例；年龄7～ 80岁,平均(45 ± 15)岁；其中眼眶淋巴瘤22例,非眼眶淋巴瘤病变65例.b值取0、700 s/mm2,测量病灶的ADC值、病灶对侧颞叶脑白质ADC值,计算二者比值(ADCR),采用ROC曲线评价病灶ADC值及ADCR值的诊断价值.结果 眼眶淋巴瘤ADC值及ADCR分别为(0.77 ±0.17)×10-3 mm2/s、0.89±0.21;非眼眶淋巴瘤病变ADC值及ADCR分别为(1.36±0.38) ×10-3 mm2/s、1.51 ±0.43;眼眶淋巴瘤ADC值及ADCR值低于非眼眶淋巴瘤病变(t值分别为-9.620和-9.003,P值均＜0.001).ADC值及ADCR值诊断眼眶淋巴瘤的ROC曲线下面积分别为0.94 ±0.03,0.91 ±0.03.ADC值以0.804×10-3 mm2/s为阈值,与病理学结果对照,诊断眼附属器淋巴瘤的敏感度为77.3％,特异度为98.4％,准确率为93.1％,与病理结果行一致性检验,kappa值为0.806.ADCR值以0.956为阈值,诊断眼附属器淋巴瘤的敏感度为77.3％,特异度为92.3％,准确率为88.5％,与病理结果行一致性检验,kappa值为0.696.结论 DWI在眼眶淋巴瘤诊断中具有重要参考价值,可以提高其诊断正确率.“,”Objective To investigate the diagnostic value of apparent diffusion coefficient (ADC)for discriminating orbital lymphomas from other orbital mass lesions.Methods In this prospective study,87 subjects (22 orbital lymphomas and 65 other orbital mass lesions) were enrolled.These patients underwent serial MR and echo-planar DW imaging examination of the orbits with b values of 0 and 700 s/mm2 at 1.5 T MR (GE Signa Excite).ADC maps were reconstructed,and the ADC values of the orbital masses were calculated.Mass ADC was also compared with that of normal-appearing white matter (ADC ratio,ADCR).The receiver operating characteristic curves (ROC) were constructed using optimal cut point of ADC and ADCR to differentiate between orbital lymphomas and other orbital mass lesions.The areas under the ROC curve for ADC and ADCR were also calculated.Results The mean ADC and ADCR of orbital lymphomas were (0.77 ± 0.17) × 10-3 mm2/s and 0.89 ± 0.21,respectively.The mean ADC and ADCR of other orbital mass lesions were (1.36 ± 0.38) × 10-3 mm2/s and 1.51 ± 0.43,respectively.Lymphomas had lower ADCs and ADCRs than other orbital mass lesions (t =-9.620,-9.003,P =0.000).The areas under the ROC curves of ADC and ADCR diagnosing lymphoma were 0.94±0.03 and 0.91 ±0.03,respectively.An ADC of less than 0.804 × 10-3 mm2/sec and ADCR of less than O.956 were optimal for predicting lymphoma (sensitivity,77.3％ for both; specificity,98.4％ and 92.3 ％,respectively ; and accuracy,93.1％ and 88.5 ％,respectively).Compared with pathological results,both ADC and ADCR had high correlations (Kappa values were 0.806 and 0.696,respectively).Conclusion Diffusion-weighted imaging can be applied as a complementary tool in the detection of orbital lymphomas.