兔VX2软组织肿瘤模型的建立及扩散张量成像研究初探

目的:建立恶性软组织肿瘤动物模型并初步探讨扩散张量成像(DTI)诊断软组织肿瘤的可行性及价值。方法:20只新西兰大白兔,右侧大腿近段注射VX2肿瘤组织悬液0．2 ml,于肿瘤组织接种后第40天行MRI常规扫描和 DTI成像,扫描图像经AW 4．0工作站处理,计算并分析肿瘤实质区、坏死区、肿瘤周边区、肿瘤邻近正常肌肉及对侧正常肌肉的平均ADC值、部分各向异性值(FA)、各向同性值(Iso)和体积与各向异性比值(VrA)。结果:所有兔大腿肌肉VX2 肿瘤模型均成功建立。肿瘤实质区与肿瘤坏死区、肿瘤周边区、邻近及对侧正常肌肉的FA值相比,差异均有极显著性意义(P<0．01)。肿瘤实质区与肿瘤坏死区、邻近及对侧正常肌肉的平均ADC值和VrA值差异有极显著性意义(P<0．01), 与瘤周区差异无显著性意义(P>0．05)。肿瘤邻近正常肌肉与对侧正常肌肉各参数值差异无显著性意义(P>0．05)。Iso 值在正常肌肉与不同区域肿瘤组织间差异有显著性意义(P<0．05)。结论:兔VX2软组织肿瘤模型可作为软组织肿瘤 MRI研究的动物模型,扩散张量成像能用于评价软组织肿瘤的内部结构特征及与周围组织的关系,其对良、恶性软组织肿瘤鉴别诊断的价值有待选一步研究。

Establishment of VX2 Soft Tissue Tumor Model and Diffusion Tensor Imaging Study in Rabbits--a Preliminary Report

Objective:To establish an experimental animal model of malignant soft tissue tumor and evaluate the feasibility of diffusion tensor imaging(DWI)for the diagnosis of soft tissue tumor. Methods: 20 New Zealand white rabbits were implanted with 0. 2ml VX2 tumor tissue suspension in the right proximal thighs. MRI were performed after 40 d,the images were transmitted to AW 4. 0 workstation. The average diffusion coefficient (ADC) , fractional anisotropy (FA), isotropic (Iso) ,volume ratio anisotropy (VrA) of the solid area,the necrosis area,the peripheral area of the tumor,the normal muscle adjacent to the tumor and the normal muscle of the contralateral thigh were calculated and analyzed. Results: In all experimental animal models of rabbit, VX2 soft tissue tumors were successfully established. The difference of FA between the solid area and the necrosis area,the peripheral area of the tumor,the normal muscle of adjacent and contralateral thigh was statistically significant (P<0. 01). The ADC and VrA of the solid area of tumors had statistical difference between the necrosis area of tumor,the adjacent and contralateral normal muscle (F<0. 01) ,but had no statistic difference between the peripheral area of tumors. The difference of ADC,FA, VrA and Iso between the adjacent and contralateral normal muscle was not statistically significant. The Iso of the normal muscle had statistic difference with the tumor. Conclusion: The animal model of rabbit VX2 soft tissue tumor can be used as an experimental animal model to study the MRI of soft tissue tumors. DTI is beneficial to demonstrate the structure of soft tissue tumor and its relationship with adjacent tissues. Further study is needed to evaluate the value of DTI in the differentiation of benign and malignant soft tissue tumor.