脑肿瘤动态增强MRI与血管生成的对照研究

Comparative study between dynamic contrast-enhanced MR imaging and vascularity of brain tumors

目的 探讨动态增强MRI评价脑肿瘤血管生成的价值。方法 对 3 9例脑肿瘤动态增强MRI及病理资料进行对照研究。绘制动态图像信号强度 时间曲线 ,计算首过斜率、渗透斜率 ;肿瘤行MVD和VEGF检测。结果 各级脑肿瘤MVD值有上升趋势 ,但差异无显著性意义 ;VEGF表达差异有显著性意义。首过斜率与MVD及组织学分级成正相关。渗透斜率与VEGF成弱相关 ;渗透斜率与组织学分级成正相关 ,各级间差异有显著性意义。结论 动态增强MRI可较好地评价脑肿瘤血管生成特性。

Objective To explore the value of dynamic contrast-enhanced MR imaging in brain tumors grading, and to assess tumor vascularity of brain tumors. Methods Dynamic contrast-enhanced MR imaging and pathological findings of 39 cases of brain tumors were analyzed. The contrast agent was Gd-DTPA with a dose of 0.1 mmol/kg. The 3D-FLASH sequence were performed with the following parameters: 22/6 ms (TR/TE), 5 mm section thickness, and acquisition time of 25 seconds per volume of 8 slices. The sequences were acquired 12 times immediately after intravenous bolus administration of contrast agent. Signal intensity values measured over time in regions of interest (ROIs), and vessels were analyzed to produce the curve. The first-pass slope and permeability slope were calculated from the data. Microvessel density (MVD) and vascular endothelial growth factor (VEGF) protein expression in all cases were examined. Results Histological examination revealed 13 grade Ⅳ, 13 grade Ⅲ, 11 grade Ⅱ, 2 grade Ⅰ among the 39 cases. Despite a tendency up in different grades, there was no statistically significant among values of MVD in any of groups ( P >0.05). Differences of the VEGF expressions from different grades were statistically significant ( P <0.05). There was a positive correlation ( r=0.549,P =0.001) between first-pass slope and the values of MVD and also a positive correlation( r=0.469,P =0.005) between first-pass slope and tumor grade. One way analysis of variance showed that differences of first-pass slope were statistically significant in different grades ( F=4.097,P =0.027). There was a weak correlation ( r=0.385,P =0.016) between permeability slope and VEGF expressions, but a strong correlation ( r=0.553,P =0.00026) between permeability slope and tumor grades. One way analysis of variance showed statistically significant differences of permeability slope in different grades( F=6.442,P = 0.001 ). Conclusion Dynamic contrast-enhanced MR imaging can assess the vascularity of brain tumors nicely, not only the blood supply of tumors, but also the permeability of the microvessels. This technique has a good prospect in clinical utilization for tumor grading and prognosis.