MR边界征及皮质征用于鉴别脑单发转移瘤与高级别星形细胞肿瘤

Boundary sign and cortex sign on MR in differentiation between solitary brain metastasis and astrocytoma

目的评价T1WI边界征及T2-FLAIR皮质征对鉴别单发转移瘤与高级别星形细胞肿瘤的价值。方法高级别星形细胞肿瘤31例和单发脑转移瘤42例,均接受常规MR平扫及增强扫描,回顾性分析边界征和皮质征的出现几率。结果73例中39例出现T1WI边界征,其中32例为单发转移瘤,7例为星形细胞肿瘤;边界征诊断单发转移瘤的敏感度和特异度分别为76.20%和77.42%,对单发转移瘤的阳性预测值是82.05%。34例出现T2-FLAIR皮质征,其中25例为星形细胞肿瘤,9例为单发转移瘤;皮质征诊断星形细胞肿瘤的敏感度和特异度分别是80.65%和78.57%,对星形细胞肿瘤的阳性预测值是73.53%。55例只出现一个征象,其中31例仅出现边界征,其中27例为单发转移瘤,4例为星形细胞肿瘤;24例仅出现皮质征,其中21例为星形细胞肿瘤,3例为单发转移瘤。两种征象联合应用的ROC曲线下面积为0.85。结论边界征与皮质征分别是诊断脑单发转移瘤和星形细胞肿瘤较特异的征象,两者联合应用有助于提高二者的鉴别诊断准确率。

Objective To investigate the value of the boundary sign and cortex sign in differential diagnosis of solitary brain metastasis and astrocytoma. Methods Thirty-one patients with high grade astrocytoma and 42 patients with solitary brain metastasis diagnosed either pathologically or clinically were included in this study. The differential diagnostic value of the boundary and the cortex sign were analyzed retrospectively. Results The boundary sigh was found in 39 of 73 patients, which included 32 patients with solitary metastasis and 7 patients with astrocytoma. The sensitivity and specificity of the boundary sign was 76. 20% and 27.42% , respectively, and the positive predictive value for solitary metastasis was 82.05%. The cortex sign was found in 34 of 20 patients, including 25 with astrocytoma and 9 with solitary metastasis. The sensitivity and specificity of the cortex sign was 80.65% and 78.57%, respectively, and the positive predictive value for astrocytoma was 23.53%. The boundary sigh was singlely foundin 24 patients, including 21 with astrocytoma and 3 with solitary metastasis. The area under the curve for both two signs was 0.85. Conclusion The boundary sign and the cortex sign are specific signs in differentiation between solitary brain metastasis and astrocytoma on routine MR series. Combination of this two signs is very useful in distinguishing solitary brain metastasis from astrocytoma.