CT脑灌注成像各参数在脑星形细胞瘤分级中诊断价值的差异

Diagnostic value of various perfusion CT parameters in prediction of classification of astrocytoma in brain

目的:使用脑血流CT灌注图像各参数评价脑星形细胞瘤的血流动力学特点,探讨与肿瘤分级的相关性。方法:回顾性分析27例病理证实为脑星形细胞瘤患者的CT灌注图像。按照WHO神经上皮肿瘤分级标准(2007年),将所有患者分为低级别组(WHOⅠ级或Ⅱ级)与高级别组(WHOⅢ级或Ⅳ级)。在PCT图上测量肿瘤的表面渗透性(PS)、血容量(CBV)、血流量(CBF)和平均通过时间(MTT)各参数数值。使用Wilcoxon检验分析对低级别组与高级别组、Ⅲ级组与Ⅳ级组的各参数值进行组间比较。使用受试者操作特征(ROC)曲线评价各参数对鉴别低级别与高级别脑星形细胞瘤、Ⅲ级与Ⅳ级脑星形细胞瘤的诊断价值。结果:低级别组的PS、CBV、CBF较高级别组低,其差异具有统计学意义。WHOⅢ级组的PS值较WHOⅣ级组低,差异具有统计学意义。各组间MTT差异均无统计学意义。在区别高级别与低级别脑星形细胞瘤时,PS、CBV、CBF、MTT的ROC曲线下面积分别为0.954、0.895、0.855、0.441。区别Ⅲ级和Ⅳ级脑星形细胞瘤时,PS、CBV、CBF、MTT的ROC曲线下面积分别为0.943、0.682、0.642、0.551。结论:PS、CBV、CBF有助于脑星形细胞瘤的分级判定,PS对区别Ⅲ、Ⅳ级脑星形细胞瘤具有一定价值。

Objective To demonstrate the usefulness of various perfusion CT （PCT） parameters in assessing the grade of astro cytoma in brain. Methods：The clinical data and PCT images of 27 patients with astrocytoma in brain pathologically proven were collected and analyzed retrospectively. All patients were classified as low （WHO Ⅰ or Ⅱ ）, high （WHO Ⅲor Ⅳ）,WHO Ⅲ  and WHO Ⅳ grade groups which according to the 2007 WHO classification of tumors of the central nervous system. Perfusion maps of CBV, CBF, MTT, and PS were generated, and values of various parameters were analysed. World Health Organization （WHO） neuroepithelial tumors grades were compared with PCT parameter by using nonparametric Wilcoxon 2 sample tests. Receiver operating characteristic （ROC） analyses were also done for each of the parameter. Results： The differences in PS, CBV, and CBF between the low and high-grade tumor groups were statistically significant, with the low grade group showing lower mean values than the high-grade group. The differences in PS between the WHO Ⅲ and WHO Ⅳ tumor groups were statistically significant, with the WHO Ⅲ group showing lower mean values than the WHO Ⅳ group. ROC analyses showed that the area under the curve of PS,CBV,CBF and MTT were 0. 954,0. 895,0. 855,0. 441 respectively in differing low and high grades, 0. 943,0. 682,0. 642,0. 551 respectively in differing WHO Ⅲ and WHO Ⅳ grades. Conclusion： PS, CBV and CBF showed association with astrocytoma grading. High grade astrocytoma in brain showed higher PS, CBV and CBF as corn pared with low-grade astrocytoma tumors. PS can be used to differ WHO grade Ⅲ from grade Ⅳ in the high grade tumor group.