星形细胞瘤MR灌注成像的有关病理学基础

The Basic Pathology Related with MR Perfusion of Astrocytoma

目的 探讨MR灌注成像在星形细胞瘤术前病理分级中的应用价值,并与血管内皮生长因子(VEGF)表达 对照,评估VEGF表达与脑血容量的相关性。资料与方法 28例星形细胞瘤患者术前行MR常规及MR灌注扫 描,术后经病理组织学检查,并采用免疫组织化学染色,观察VEGF表达情况。原始灌注图像数据经工作站软件处 理,获得MR灌注曲线及彩色图谱,测量肿瘤实质部分及瘤周水肿区最大相对脑血容量(rCBV)并将所测数值进行 统计学分析。免疫组织化学染色计算每一标本的VEGF表达程度,将VEGF表达程度与rCBV进行相关分析。结 果 在MR灌注曲线及彩色图谱中,高分级星形细胞瘤实质部分及瘤周水肿区最大灌注处表现为高灌注,低分级星 形细胞瘤表现为等或低灌注为主。低分级星形细胞瘤实质部分及瘤周水肿区最大rCBV值为1．88±0．84,1．03± 0．40。高分级星形细胞瘤实质部分及瘤周水肿区最大rCBV值为3．07±1．23,1．61±0．70;两组间肿瘤实质部分及瘤 周水肿区最大rCBV值差异均有统计学意义(P<0．01,P<0．05)。VEGF不同表达程度的rCBV差异有统计学意义 (P<0．01),VEGF表达程度与rCBV成正相关,r8值为0．817,P<0．001。 结论 星形细胞瘤MR灌注成像与病理 分级和VEGF有良好相关性,结合常规MR,可显著提高星形细胞瘤术前病理分级的准确性,具有重要临床价值。

Objective To evaluate the role of MR perfusion in the preoperative histological grading of astroeytomas, and investigate the correlation of rCBV（relative cerebral blood volume） with vascular endothelial growth factor （VEGF）. Materials and Methods Conventional MR and MR perfusion were performed in 28 pre-operative patients of astrocytomas confirmed with histological results,and immunohistochemical stain method was used to demonstrate the situation of VEGF protein expression. The patients＇ raw data were transferred to workstation and processed to obtain time-signal inteasity curves and color maps of CBV. The maximum relative CBV values were measured in both tumor and the peritumoral edema and analyzed statistically. According to the situation of VEGF protein expression, the correlation between rCBV and VEGF was analyzed. Results The MR perfusion curves and maps of different grade astroeytomas had different characteristics. The maximal rCBV of tumor and peritumoral edema in lowgrade were 1.88 ± 0.84,1.03 ± 0.40,respectively, and were 3.07 ± 1.23,1.61 ± 0.70 in the high-grade astrocytomas respectively. The difference in maximum rCBV of tumor and peritumoral edema between the two groups was statistically significant （ P 〈 0.01, P 〈 0.05）. The difference in maximum rCBV between the different VEGF expression levels was statistically significant （P〈0.01）, and there was positive correlated with VEGF expression levels and rCBV （ rs = 0. 817, P 〈 0. 001 ）. Conclusion MR perfusion imaging is of great value in the preoperative prediction of grade in the astroeytomas, because there is good correlation between rCBV, histologic grading and VEGF, which can greatly improve diagnostic accuracy before surgery combined with conventional MR images.