扩散加权成像鉴别诊断恶性胶质瘤与单发脑转移瘤的b值优化

Optimizing b-value in Diffusion Weighted Imaging for Differentiating Malignant Glioma and Solitary Brain Metastasis

目的探讨不同b值扩散加权成像(DWI)对恶性胶质瘤与单发脑转移瘤的鉴别诊断价值,寻找鉴别两者的最佳b值。资料与方法对25例高级别胶质瘤和15例单发脑转移瘤患者行DWI扫描,b值取1000、3000、5000 s/mm2,测量瘤体及瘤周表观扩散系数(ADC)值。结果当b值取1000、3000、5000 s/mm2时,恶性胶质瘤与单发脑转移瘤瘤周ADC值分别为(1.31±0.10)×10-3 mm2/s和(1.65±0.19)×10-3 mm2/s、(0.98±0.13)×10-3 mm2/s和(1.12±0.14)×10-3 mm2/s、(0.69±0.10)×10-3 mm2/s和(0.76±0.08)×10-3 mm2/s,差异有统计学意义(t=-6.355、-2.972、-2.392,P<0.05)。当b值取1000 s/mm2时,瘤周ADC值的ROC曲线下面积为0.98,敏感度、特异度、阳性预测值、阴性预测值分别为100.0%、88.0%、79.0%、100.0%。结论 b值取1000 s/mm2时瘤周ADC值对于鉴别恶性胶质瘤与单发脑转移瘤最佳。

Purpose To optimize b values in diffusion weighted imaging （DW1） for diagnosing malignant glioma and solitary brain metastasis.Materials and Methods Three different b-value （b=1000,3000 and 5000 s/mm2） were used in twenty-five patients with high-grade glioma and fifteen patients with solitary metastasis to measure ADC value within the tumor and peritumoral area.Results With the b-value 1000,3000 and 5000 s/mm2,the ADC value in the peritumoral regions was （1.31± 0.10）× 10-3 mm2/s and （1.65±0.19）×10-3 mm2/s,（0.98±0.13）×10-3 mm2/s and （1.12±0.14）×10-3 mm2/s,（0.69 ± 0.10）× 10.3 mm2/s and （0.76± 0.08）× 10-3 mm2/s respectively with statistically significant （t=-6.355,-2.972 and-2.392,P＜0.05）.When b-value was 1000 s/mm2 and the area under the ROC curve of the peritumoral region was 0.98,the sensitivity,specificity,positive predictive value and negative predictive value were 100.0％,88.0％,79.0％ and 100.0％ respectively.Conclusion The b-value of 1000 s/mm2 is optimal to diagnose high-grade gliomas and solitary metastases using peritumoral ADC.