星形细胞瘤MRI弥散成像、瘤周水肿与HIF-1α表达水平的相关性分析

Correlation analysis on MRI Diffusion Weighted Imaging(DWI), peritumoral edema and expression level of HIF-1α in cerebral astrocytoma

目的通过磁共振成像（MRI）和MRI定量指标来研究星形细胞瘤弥散成像、瘤周水肿与肿瘤缺氧诱导因子-1α（HIF-1α）表达水平的相关性,以及星形细胞瘤在缺氧环境下的浸润、生长、增殖能力及恶性度,更好地指导临床治疗及预后评估。方法选取经手术病理证实的33例星形细胞瘤患者,术前均进行磁共振弥散加权成像（DWI）检查,并计算肿瘤实质部分的ADC值;计算MRI水肿指数（EI）,采用免疫组化法检测HIF-1α的表达情况。结果低级别星形细胞瘤（WHOⅠ－Ⅱ级）的平均ADC值高于高级别星形细胞瘤（WHOⅢ－Ⅳ级）,低级别星形细胞瘤平均EI值低于高级别星形细胞瘤,高、低级别星形细胞瘤中HIF-1α均有表达,且星形细胞瘤的HIF-1α表达水平随着星形细胞瘤临床病理程度增高而加强,低级别星形细胞瘤内部平均HIF-1α指数低于高级别星形细胞瘤;肿瘤区ADC值与HIF-1α呈显著负相关,肿瘤区ADC值和EI值呈负相关,HIF-1α和EI值无明显相关性。结论核磁共振定量参数ADC值、EI值与常规MRI联合应用及HIF-1α的表达可显著提高星形细胞瘤术前分级的准确性,进而指导治疗方案的选择;MRI虽然能很好地间接反应星形细胞瘤的分子生物学行径,但瘤周水肿不能用单一理论解释。

Objective To explore the value of the relationship among different MRI quantitative parameters, peritumoral edema and the expression of hypoxia inducible factor-1 alpha（HIF-1α） in the preoperative diagnosis of cerebral astrocytoma. The ability of growth,invasion and generation in the hypoxia condition will be better expressed by the diagnosis of MRI level,which will be very helpful for evaluating pathological grade, preferably guiding clinical theraphy and the evaluating prognosis in cerebral astrocytoma. Methods Thirty-three cases of astrocytoma proved by operation and pathology were sutdied by DWI; The volume of tumor and the extent of peritumorous brain edema（PTBE） were determined on MRI. Edema index（EI） was used to evaluate the extent of PTBE; HIF-1α on the specimens of the tumors was stained with immunohistochemical method. Results The average ADC value of low grade（grade Ⅰ-Ⅱ）astrocytoma is higher than that of high grade（grade Ⅲ-Ⅳ） astrocytoma. There were significantly different between the low grade astrocytoma and high grade astrocytoma. The average EI value of low grade（grade Ⅰ-Ⅱ） astrocytoma is lower than that of high grade（grade Ⅲ-Ⅳ） astrocytoma. The expression level of HIF-1α in cerebral astrocytoma is：low grade astrocytoma：（20.08±10.01）%; high grade astrocytoma：（47.91±19.03）%. They were significantly different between the two group. There was no obvious significant correlation existed between the value of HIF-1α LIs and EI. ADC and HIF-1α LIs, EI showed significantly negative correlation. Conclusion The MRI quantitative parameters like the value of ADC,EI associating with conventional MRI and the expression of HIF-1α can significantly raise the accuracy of preoperative evaluation of cerebral astrocytoma and choose the effective therapy plan. Cerebral astrocytoma with rich vascular components are often accompanied by peritumoral edema but it can＇t be explained by only one theory.