基于活体MRI的3D流-固耦合模型分析对症状性大脑中动脉粥样硬化斑块的研究

发布时间：2018-09-09 13:59

【摘要】：目的:以症状性大脑中动脉(MCA)斑块的活体高分辨率磁共振成像(HR-MRI)数据为基础,建立3D完全耦合的流-固耦合(FSI)模型,探索不同组分MCA斑块的生物力学特征。方法:研究对象为拟行介入手术治疗的12例症状性单侧MCA局限性动脉粥样硬化狭窄的患者。首先,术前对MCA管壁行HR-MRI作为力学建模的形态学依据;其次,利用相位对比MRI技术和DSA引导下的测压微导管分别采集MCA狭窄前端的血流参数和血压数据作为载荷条件,并对目标血管的3D几何结构进行网格生成等前处理,导入有限元程序软件ADINA(ADINA RD,Inc,USA)进行FSI求解;最后,从3D FSI结果中提取3个力学指标值:最大主应力(MPS)、最大主伸长比(STRETCH-P1)和最大剪应力(FMSS),分析比较不同狭窄程度和不同斑块成分的各项力学指标的差异。结果:按照狭窄率分组比较发现,轻中度狭窄组的MPS、STRETCH-P1和FMSS与重度狭窄组之间的差异均无统计学意义(P=0.9323、0.3872和0.1271)。分析不同斑块成分发现,含"脂质核心"斑块的层面中MPS稍高于含"纤维成分"斑块(P=0.0744),STRETCH-P1明显高于"纤维成分"斑块(P=0.0169),FMSS显著低于"纤维成分"斑块(P=0.0021)。结论:症状性MCA粥样硬化病变中,"脂质核心"斑块的主应力和主伸长比均不同程度地高于"纤维化"斑块,提示富含脂质坏死核心斑块的机械负荷较大、可能有相对较高的破裂风险。
[Abstract]:Aim: based on the in vivo high resolution magnetic resonance imaging (HR-MRI) data of symptomatic (MCA) plaques of middle cerebral artery (MCA), a 3D fully coupled fluid-solid coupled (FSI) model was established to explore the biomechanical characteristics of MCA plaques with different components. Methods: twelve patients with symptomatic unilateral MCA with localized atherosclerotic stenosis were studied. Firstly, HR-MRI was performed on the wall of MCA before operation as the morphological basis of mechanical modeling. Secondly, the blood flow parameters and blood pressure data of the front end of MCA stenosis were collected by phase contrast MRI and DSA guided microcatheter as loading conditions. The 3D geometric structure of the target vessel is processed by mesh generation, and the finite element software ADINA (ADINA RD,Inc,USA is introduced to solve the FSI problem. Three mechanical indices were extracted from 3D FSI results: maximum principal stress (MPS), maximum principal elongation ratio (STRETCH-P1) and maximum shear stress (FMSS),. Results: according to the rate of stenosis, there was no significant difference in MPS,STRETCH-P1 and FMSS between mild and moderate stenosis group and severe stenosis group (P < 0. 932 3 ~ 0. 3872 and 0.1271). It was found that MPS in the plaques with "lipid core" was slightly higher than that in the plaques with "fibronectin" (P0. 0744), STRETCH-P1 was significantly higher than that in "fibronectin" plaques (P0. 0169), and FMSs were significantly lower than those in "fibronectin" plaques (P0. 0021). Conclusion: in symptomatic MCA atherosclerotic lesions, the principal stress and the ratio of principal elongation of "lipid core" plaques are higher than those of "fibrosis" plaques in varying degrees, suggesting that the mechanical load of plaque rich in lipid necrosis core is greater than that of "fibrosis" plaque. There may be a relatively high risk of rupture.
【作者单位】：第二军医大学附属长海医院影像医学科;剑桥大学附属Addenbrooke's医院放射科;
【基金】：国家自然科学基金面上项目(31470910) 上海市市级医院新兴前沿技术联合攻关项目(SHDC12013110) 全军医学科研“十二五”计划重点课题(BWS12J026)
【分类号】：R445.2;R743

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