MRI“晕征”和“黑环征”对鉴别出血性海绵状血管瘤与其他脑肿瘤出血的价值

The Diagnostic Value of the Halo Sign and the Hypointense Signal Rim on MRI in Differentiation of Cavernous Angioma from Other Hemorrhagic Masses

目的评估T1WI"晕征"和T2WI"黑环征"对鉴别出血性海绵状血管瘤(cavernous angioma,CA)及其他脑肿瘤出血的价值。资料与方法 84例脑内肿瘤合并急性或亚急性出血患者,其中CA29例,高级别星形细胞肿瘤31例,转移瘤24例。所有患者均行MR平扫及增强扫描,分析"晕征"和"黑环征"的出现概率。结果 24例出现T1WI"晕征",其中17例(58.62%)为CA,3例(9.68%)为星形细胞肿瘤,4例(16.67%)为转移瘤。T1WI"晕征"诊断CA的敏感性和特异性分别为58.62%、87.27%,阳性预测值为70.83%;59例出现T2WI"黑环征",其中26例(89.66%)为CA,15例(43.39%)为星形细胞肿瘤,18例(75%)为转移瘤。T2WI"黑环征"诊断CA的敏感性、特异性分别为89.66%、40%,阳性预测值为44.07%。两种征象联合应用诊断CA,受试者工作特征(ROC)曲线下面积Az=0.766。结论 T1WI"晕征"是诊断出血性CA较特异的征象;T2WI"黑环征"敏感性较高,但特异性较低,两种征象联合应用,对CA的诊断以及与其他脑肿瘤合并出血相鉴别准确性较高。

Objective To determine whether halo sign and T2 hypointense signal rim are useful for the differentiation of cavernous angioma from other hemorrhagic cerebral masses. Materials and Methods The MR images of 84 patients with acute or subacute cerebral hemorrhagic lesions with perilesional edema （29 cavernous angiomas,31 high grade astrocytomas,24 metastatic tumors） were retrospectively evaluated for the presence of the halo sign and T2 hypointense signal rim. Results The halo sign was found in 17 （58.62%） of 29 cavernous angiomas,in 4（16.67%） of 24 metastases,and in 3（9.68%） of 31 astrocytomas. Sensitivity,specificity,and positive predictive value of this sign for cavernous angioma were 58.62%,87.27% and 70.83%,respectively. The profoundly T2 hypointense signal rim was found in 59 of 84 patients,which included 26 patients with cavernous angioma,15 patients with astrocytoma and 18 patients with metastasis. The sensitivity,specificity and the positive predictive value of this sign for cavernous angioma were 89.66%,40% and 44.07%,respectively. The area under the ROC curve for the both signs was 0.766. Conclusion The halo sign is a specific sign in cavernous angioma,while T2 hypointense signal rim is very sensitive but not very specific in cavernous angioma.If these two signs are analyzed together,it would be very useful in differentiating cavernous angioma from other hemorrhagic cerebral tumors.