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的关键放射学特征，其与肿瘤的基因改变密切相关。本研究旨在探讨间变性胶质瘤患者的磁共振成像（MR imaging）肿瘤对比增强表现、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。研究回顾性分析了240例经组织学证实为间变性胶质瘤的患者的磁共振图像，测量了T2高信号区域、增强后T1加权像上的对比增强区域及坏死区域的体积。本研究对VEGF高、低表达患者的增强体积与坏死体积之比进行了比较，并将该比值进一步应用于生存分析。曼-惠特尼检验结果显示，VEGF低表达患者的增强-坏死体积比显著高于VEGF高表达患者（p=0.009）。此外，多变量Cox回归分析表明，增强/坏死体积比是无进展生存期（p=0.004）与总生存期（p=0.006）的显著预测因子。上述研究结果提示，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，且该比值可作为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。