4D PC-MRI血流动力学参数与主动脉夹层假腔血栓化的关系及模拟预测研究

The false lumen thrombosis in aortic dissection (AD) is recognized as an important factor in evaluating the efficacy of thoracic endovascular aortic repair (TEVAR) and aortic remodeling. The development of false lumen thrombosis is strongly influenced by the local hemodynamics, however, their relationship is currently not clear. The results in our previous studies demonstrated that aortic morphology, intimal flap, tears, true and false lumens influenced the dissection hemodynamics together, which lead to thrombus formation. Meanwhile, the 4D phase-contrast MRI has proven to be a promising tool for quantification of blood flow pre- and post- TEVAR. The current project focuses on the following aspects: (1) to observe the difference of thrombus formation between patients who underwent best medical treatment and TEVAR; (2) to explore the quantitative relations and predictors of poor outcome using 4D phase-contrast MRI parameters and follow-up results in two groups; (3) to validate a novel computational model for predicting false lumen thrombosis in AD; (4) to identify the high risk group of uncomplicated AD who would have a poor false lumen thrombus formation and benefit from early TEVAR. After these experiments, we hope to get the quantitative relationship between 4D phase-contrast MRI parameters and the false lumen thrombosis, and validate a novel and accurate computational model for the prediction of false lumen thrombosis in AD, which would benefit for patients with uncomplicated type B AD, and optimize the indication and strategy of TEVAR.

主动脉夹层（AD）假腔血栓化程度是评估胸主动脉腔内修复（TEVAR）疗效和主动脉重塑的重要因素。血流动力学相关参数直接和间接地影响了假腔血栓化，但两者间的量化关系目前尚不清楚。我们前期研究显示，主动脉的解剖形态、内膜片、真假腔、破口等共同影响AD血流动力学，进而影响假腔血栓形成；4D PC-MRI影像可定量化分析血流动力学参数。我们此次拟①通过获取非复杂AD的影像学资料，分析单纯药物和TEVAR治疗的假腔血栓化程度；②通过两组病例假腔血栓化程度与4D PC-MRI血流动力学参数的变化，寻找两者间的量化关系和影响预后的危险因素；③通过两者的量化关系和临床预后优化AD假腔血栓形成的生化模拟工具；④通过生化模拟系统筛选药物保守难以假腔血栓形成、倾向恶化进展的非复杂AD亚群。如获成功，可为非复杂AD的病例筛选、TEVAR指征把握和手术方案优化提供实验依据，提高TEVAR的精准化。

腔内支架修复(TEVAR)已成为治疗胸主动脉夹层(TAD)的首选术式，假腔内血栓化是评判术后疗效的关键因素。寻找血栓化的危险因素，阐明其机制，有助于改善预后。TAD假腔形态各异，血流分布复杂多变，单纯依赖CT影像评判具有较大局限性。我们前期通过大动物建模探索TAD急性进展的血流动力学特征，结果显示夹层撕裂层次影响夹层的进展，内膜片靠近外膜较靠近内膜时夹层更易进展，破裂风险更大。解剖因素和血流动力学变化共同影响夹层的进展和稳定。基于前期研究，本研究进一步构建了具有多发破口的猪主动脉夹层模型，并进行了有创Doppler导丝血流检测和基于4D PC-MRI技术的夹层血流动力学分析。在真实世界中，对不同解剖形态TAD病例TEVAR术前和术后血流参数变化进行了量化分析和内在关联探讨，从临床角度对不同血流动力学参数解读，得到了理想的预期结果，为更好的理解TAD血流动力学变化提供了新视角。为减少影像数据预处理工作量，加快后处理的速度，课题组利用人工智能辅助 TAD的增强CT血管成像技术成功构建了自动分割模型，并在临床病例中尝试应用。通过本项目的前期工作，从4D PC-MRI后处理分析获取了一部分与 TEVAR预后及假腔重塑相关的血流动力学相关参数，可为TEVAR精准修复提供重要的理论依据。本项目虽已到达预期结果，但样本量较少，尚未得出可靠的统计学指标。这些正是后续深入研究的重点所在。