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  

Symptomatic atherosclerotic plaque of middle cerebral artery by in vivo MRI-based 3D fluid-structure interaction analysis

作　　者：彭雯佳[1] 滕忠照[2] 江远亮 陈士跃[1] 刘崎[1] 陆建平[1] 

机构地区：[1]第二军医大学附属长海医院影像医学科,上海200433 [2]Cambridge、UK、CB20QQ、剑桥大学附属Addenbrooke's医院放射科

出　　处：《放射学实践》2015年第12期1195-1202,共8页Radiologic Practice

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)

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 R&D,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。Objective：Based on the in vivo high-resolution magnetic resonance imaging （HR-MRI） of symptomatic atherosclerotic middle cerebral artery （MCA）, 3D fully coupled fluid-structure interaction （FSI） models were constructed to assess biomechanical behaviors of the varieties of components in MCA plaques. Methods：Twelve symptomatic patients with unilateral atherosclerotic stenosis of MCA who were prepared to be treated by interventional therapy were enrolled in our study. Firstly, affected MCA was examined by HR-MRI, and the geometric data were extracted from the wall images of HR- MRI for constructing FSI models. Secondly, the flow rate and regional blood pressure proximal to the stenotic MCA were separately measured by phase-contrast MRI and DSA guided pressure measurement using microcatheter. After a series of pre-processing steps of 3D reconstruction and mesh generation process,the coupled FSI models were solved by a finite-ele- ment package ADINA （ADINA Rb-D,Inc,USA）. Finally,the maximum principal stress （MPS） ,maximum principal stress- elongation ratio （STRETCH-P1） and flow maximum shear stress （FMSS） were extracted from 3D FSI solutions for compa- ring in terms of stenosis extent and plaque components. Results：The differences of MPSs,STRETCH-Pls and FMSSs were not statistically significant between mild-moderate stenosis group and severe stenosis group （P： 0. 9323, 0. 3872 and 0. 1271）. For different plaque components, MPSs were slightly higher, STRETCH-Pls were significant higher, and FMSSs were significant lower in slices with lipid core plaque than those with fibrosis components with statistic difference （P= 0. 0744,0. 0169 and 0. 0021, respectively）. Conclusion： In symptomatic atherosclerotic MCA, plaques with lipid core pos- sessed higher MPS and STRETCH-P1 than those of fibrotic plaques, that means lipid-rich plaques may suffer relatively higher mechanical burden.

关 键 词：大脑中动脉 动脉粥样硬化 磁共振成像 斑块 流固耦合模型 

分 类 号：R445.2[医药卫生—影像医学与核医学] R543.4[医药卫生—诊断学]