Characterization of Glioma Microcirculation and Tissue Features Using Intravoxel Incoherent Motion Magnetic Resonance Imaging in a Rat Brain Model
Characterization of Glioma Microcirculation and Tissue Features Using Intravoxel Incoherent Motion Magnetic Resonance Imaging in a Rat Brain Model
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DOI：
10.1097/rli.0000000000000040
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发表时间：
2014-07-01
影响因子：
6.7
通讯作者：
Le Bihan, Denis
中科院分区：
文献类型：
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作者：
Iima, Mami;Reynaud, Olivier;Le Bihan, Denis
目的探讨17.2T磁共振弥散成像（diffusion magnetic resonance imaging，MRI）和灌注成像（perfusion magnetic resonance imaging，perfusion MRI）参数在9 L大鼠脑胶质瘤模型中的相关性，以评价肿瘤组织特征。将9 L胶质瘤细胞注射到14只Fischer大鼠脑内。植入后7或12天，在17.2 T MRI扫描仪上使用72个不同的B值（2-3025 s/mm（2））对动物进行成像。使用峰度扩散模型（ADCo和K）和双指数扩散模型（分数f（快）和f（慢）以及扩散系数D-快和D-慢）拟合信号衰减S/So，其中B值大于300 s/mm（2）。为了桥接2个模型，从双指数模型中分别估计平均扩散系数和双指数指数作为ADCo和K当量。体素内非相干运动灌注相关参数从低B值下的残留信号中获得，在扩散分量被去除后。在逐像素的基础上为每个拟合参数生成扩散和灌注图，并在肿瘤和对侧绘制感兴趣区域以检索扩散和灌注参数。所有大鼠被杀死，细胞和血管定量评估使用组织学比较扩散和灌注parameters.Results Intravoxel不连贯的运动地图清楚地突出了肿瘤区域一般异质性，组织学证实。扩散参数中，肿瘤与对侧的ADCo和K值无显著性差异，而肿瘤的K值显著高于对侧基底节（P < 0.0001），双指数指数（P <0.001）也高于对侧基底节（P < 0.001）。肿瘤中ADCo和ADCo在第7天显著高于第12天（分别为P < 0.01和P < 0.001）。峰度扩散模型中肿瘤的f（IVIM）显著高于对侧基底节（P < 0.001）。第7天肿瘤中的f（IVIM）显著高于第12天肿瘤中的f（IVIM）（P < 0.0001）。肿瘤与对侧之间的D* 值差异无统计学意义（P = 0.06）。肿瘤血管密度与f（IVIM）呈显著负相关（P < 0.05），肿瘤细胞计数与f（IVIM）呈显著负相关（P < 0.01）。
Purpose Our aim was to investigate the pertinence of diffusion and perfusion magnetic resonance imaging (MRI) parameters obtained at 17.2 T in a 9L glioma rat brain tumor model to evaluate tumor tissue characteristics.Materials and Methods The local animal ethics advisory committee approved this study. 9L glioma cells were injected intracerebrally to 14 Fischer rats. The animals were imaged at 7 or 12 days after implantation on a 17.2-T MRI scanner, using 72 different b values (2-3025 s/mm(2)). The signal attenuation, S/So, was fitted using a kurtosis diffusion model (ADCo and K) and a biexponential diffusion model (fractions f(fast) and f(slow) and diffusion coefficients D-fast and D-slow) using b values greater than 300 s/mm(2). To bridge the 2 models, an average diffusion coefficient and a biexponential index were estimated from the biexponential model as ADCo and K equivalents, respectively. Intravoxel incoherent motion perfusion-related parameters were obtained from the residual signal at low b values, after the diffusion component has been removed. Diffusion and perfusion maps were generated for each fitted parameter on a pixel-by-pixel basis, and regions of interest were drawn in the tumor and contralateral side to retrieve diffusion and perfusion parameters. All rats were killed and cellularity and vascularity were quantitatively assessed using histology for comparison with diffusion and perfusion parameters.Results Intravoxel incoherent motion maps clearly highlighted tumor areas as generally heterogeneous, as confirmed by histology. For diffusion parameters, ADCo and were not significantly different between the tumor and contralateral side, whereas K in the tumor was significantly higher than in contralateral basal ganglia (P < 0.0001), as well as biexponential index (P < 0.001). ADCo and in the tumor at day 7 were significantly higher than at day 12 (P < 0.01 and P < 0.001, respectively). f(IVIM) in the tumor from the kurtosis diffusion model was significantly higher than in contralateral basal ganglia (P < 0.001). f(IVIM) in the tumor at day 7 was significantly higher than in the tumor at day 12 (P < 0.0001). There was no significant difference for D* between the tumor and contralateral side (P = 0.06). A significant negative correlation was found between tumor vascularity and f(IVIM) (P < 0.05) as well as between tumor cell count and (P < 0.01).Conclusion Quantitative non-Gaussian diffusion and perfusion MRI can provide valuable information on microvasculature and tissue structure to improve characterization of brain tumors.