Identifying the Association of Contrast Enhancement with Vascular Endothelia Growth Factor Expression in Anaplastic Gliomas: A Volumetric Magnetic Resonance Imaging Analysis

Contrast enhancement is a crucial radiologic feature of malignant brain tumors, which are associated with genetic changes of the tumor. The purpose of the current study was to investigate the potential relationship among tumor contrast enhancement with MR imaging, vascular endothelial growth factor (VEGF) expression, and survival outcome in anaplastic gliomas. MR images from 240 patients with histologically confirmed anaplastic gliomas were retrospectively analyzed. The volumes of T2 hyperintense, contrast enhanced regions and necrotic regions on postcontrast T1-weighted images were measured. The ratio of the enhanced volume to necrotic volume was compared between patients with high versus low levels of VEGF expression and was further used in the survival analysis. The volumetric ratio of enhancement to necrosis was significantly higher in patients with low VEGF expression than in those with high VEGF expression (Mann-Whitney, p = 0.009). In addition, the enhancement/necrosis ratio was identified as a significant predictor of progression-free survival (Cox regression model, p = 0.004) and overall survival (Cox regression model, p = 0.006) in the multivariate analysis. These results suggest that the volumetric ratio of enhancement to necrosis could serve as a noninvasive radiographic marker associated with VEGF expression and that this ratio is an independent predictor for progression-free survival and overall survival in patients with anaplastic gliomas.

对比增强是恶性脑肿瘤至关重要的影像学特征，且与肿瘤的遗传学改变密切相关。本研究旨在探讨间变性胶质瘤患者的磁共振成像（MR imaging）所示肿瘤对比增强特征、血管内皮生长因子（VEGF）表达水平与生存结局之间的潜在关联。本研究回顾性分析了240例经组织学确诊的间变性胶质瘤患者的磁共振影像资料，对增强后T1加权成像（postcontrast T1-weighted images）上的T2高信号区、对比增强区域以及坏死区域的体积进行了测量。研究人员对比了VEGF高表达与低表达患者的增强体积与坏死体积的比值，并将该比值进一步应用于生存分析。结果显示，VEGF低表达患者的增强/坏死体积比显著高于VEGF高表达患者（曼-惠特尼U检验，p=0.009）。此外，多因素分析结果表明，增强/坏死体积比可作为无进展生存期（Cox回归模型，p=0.004）与总生存期（Cox回归模型，p=0.006）的显著预测因子。上述结果表明，增强/坏死体积比可作为与VEGF表达相关的非侵入性影像学标志物，且该比值是间变性胶质瘤患者无进展生存期与总生存期的独立预测因素。