128层螺旋CT全脑灌注对浸润性星形细胞瘤的分级评估

目的:评价128层螺旋CT全脑灌注(CTP)对浸润性星形细胞瘤分级定性诊断的价值。方法:选择我院90例脑肿瘤患者进行CTP检查,经手术和病理学证实为浸润性星形细胞瘤(Ⅱ~Ⅳ级)者46例纳入本研究对象。CTP采用SOMATOM Definition AS型128层螺旋CT机进行灌注扫描,应用后处理工作站对原始数据进行后处理,获得时间-密度曲线(TDC),测定肿瘤区和对侧正常组织的脑血流量(CBF)、脑血容量(CBV)、毛细血管表面通透性(PS)及对比剂达峰值时间(TTP),并对灌注参数进行统计学分析。结果:在所有病例中,全脑灌注图像平均视觉评价分数明显高于传统灌注图(P<0.01),且对病变定位更为精确。星形细胞肿瘤高级别组的CBF、CBV和PS值均显著高于低级别组(P<0.01),而TTP值的差异无统计学意义(P>0.05)。ROC曲线分析表明,CBF、CBV和PS值对鉴别高、低级别星形细胞肿瘤的ROC曲线下面积分别为0.925、0.897和0.954,采用CBF≥72.052ml/min/100g,CBV≥4.293ml/100g和PS≥6.337ml/min/100g作为分界点对鉴别高低级别星形细胞肿瘤的敏感性均为87.2%,特异性分别是83.5%、83.5%和93.0%。结论:128层螺旋CT全脑灌注有利于脑肿瘤的术前整体评估和精确定位;CTP参数CBF、CBV及PS值及TDC曲线对鉴别高、低级别星形细胞肿瘤具有较高的敏感性和特异性。

Evaluation of 128-slice spiral CT whole brain perfusion imaging in grading infiltrating astrocytomas

Objective：To evaluate the value of 128-slice spiral CT whole brain perfusion（CTP） imaging in grading infiltrating astrocytomas.Methods：Ninety patients with brain tumors underwent CTP examination and forty-six of them with astrocytic tumors（Ⅱ～Ⅳ） confirmed by operation and pathology were selected as the object of this study.128-slice helical CT whole brain perfusion imaging was performed in the 46 patients,and the data were analyzed by the software,Cerebral blood flow（CBF）,Cerebral blood volume（CBV）,time to peak（TTP） and permeability surface（PS） on the maximum perfusion area and the normal brain tissuse in the opposite side were measured.Then the Statistical analysis of the perfusion parameters was performed.Results：The average visual rating scores of whole-brain perfusion images were significantly higher than that of the traditional perfusion imaging in all cases（P0.01）,and the whole-brain perfusion images were more precise in positioning a brain tumour.High-gradc group showed significantly higher CBF,CBV and PS values as compared with the low-group（P0.01）.However,TTP values were not significantly different between 2 groups（P0.05）.The under-ROC curve areas of the CBF,CBV and PS values between these 2 grous were 0.925,0.897,and 0.954,respectively,and could help differentiate high and low grade astrocytic tumors.When the optimal limit values of these indicators for differentiation of high and low grade astrocytic tumors were selected as follows： CBF≥72.052 ml/（100 g·min）,CBV≥4.293 ml/100 g and PS≥6.337 ml/（100 g·min）,the sensitivity was 87.2%,uniformly and the specificity was 83.5%,83.5% and 93.0% respectively.Conclusion：The 128-slice spiral CT whole brain perfusion imaging conducive to the overall evaluation and accurate positioning before the tumor surgery.The CBF,CBV,and PS values of 128-slice CTP are high sensitivity and specificity for differential diagnosis of high and low grade astrocytic tumors.