高级别星形细胞瘤与脑膜瘤瘤周水肿区磁共振弥散张量成像评价

The characteristics of peritumoral edema caused by high-gade astrocytoma and meningioma on magnetic resonance diffusion tensor imaging

目的应用磁共振弥散张量成像（diffusion tensor imaging，DTI）技术定量评价高级别星形细胞瘤（Ⅲ～Ⅳ级）与脑膜瘤瘤周水肿区的弥散改变特点及二者差别。方法收集经病理学证实高级别星形细胞瘤15例，良性脑膜瘤15例。分别对二者瘤周水肿区与对侧正常脑白质区的部分各向异性（fraction anisotropy，FA）值和平均弥散系数（average diffusion coefficient，DCavg）值进行测定、对比分析。结果二者瘤周水肿区的FA值和DCavg值分别显著低于和高于对侧正常脑白质区；高级别星形细胞瘤瘤周水肿区FA值较对侧正常脑白质区降低程度显著高于良性脑膜瘤。结论应用DTI技术定量评价高级别星形细胞瘤与良性脑膜瘤瘤周水肿区的FA值及DCavg值改变特点及二者差别，可以揭示常规MR不能发现的细微病理改变及二者差异。

Objective To quantitatively evaluate the diffusion＇ changes of high - grade astrocytoma （grades III- IV ） and meningioma associated with. peritumoral edema using magnetic resonance diffusion tensor imaging （DTI）, and to compare the differences between them. Methods DTI was performed for 15 cases with high- grade astrocytoma and 16 cases with meningioma proven pathologically. Average diffusion coefficient （DCavg） values and fractional anisotropy （FA） values of peritumoral edema and the contralateral normal brain white matter were measured on DCavg and FA imagings of each patient. Compared the DCavg and FA values of peritumoral edema with contralateral normal brain white matter. Compared the DCavg and FA values of peritumoral edema in astrocytoma with meningioma. Results In astrocytoma and meningioma, the DCavg and FA values of peritumoral edema were significantly higher and lower than those of contralateral normal brain white matter in both of them, respectively. The FA values of peritumoral edema in patients with high - grade astrocytomas were significantly lower than those in patients with meningiomas. The decreased degree of the FA values of peritumoral edema between patients with high - grade astrocytomas and contralateral normal brain white matter was more severe than that of patients with benign meningioma. Conclusion Diffusion tensor imaging can evaluate quantitatively diffusion changes and differences of peritumal edema, which is a new method for clinical functional study of high - grade astrocytoma （grades III - IV ） and meningioma,and can reaveal the microcosmic pathological changes and their differences which can not obtained by normal MRI.