Hemodynamic Stress in brain vascular malformations

脑血管畸形中的血流动力学应激

• 批准号: 6469888
• 负责人: WILLIAM L YOUNG
• 金额: $ 21.41万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN FRANCISCO
• 依托单位国家: 美国
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-04-01 至 2005-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6469888
• 关键词: artery occlusion; biophysics; blood pressure; blood vessel disorder; brain circulation; cerebral aneurysm; cerebral artery; cerebroangiography; clinical research; computational neuroscience; computed axial tomography; computer simulation; diagnosis design /evaluation; disease /disorder proneness /risk; hemodynamics; heterodyning; human subject; hypotension; intracranial hematoma; magnetic resonance imaging; mathematical model; model design /development; neurosurgery; prognosis; shear stress; stroke

This project represents continuing collaboration between clinical and basic scientists to characterize the biophysical forces acting on arterial lesions. The modeling tools have been developed to the point where they can characterize the biophysical forces acting on giant cerebral fusiform aneurysms. Left untreated, giant aneurysms can continue to enlarge over the life of the patient. The risk of death or devastating morbidity approaches 85% over 5 years. To slow growth, the feeding artery is often occluded in the hope that it decreases hemodynamic stress. However, because local wall shear stress and pressure cannot be measured directly, quantitative data is lacking. We will test the primary hypothesis that treatments that decrease shear stress and pressure on the aneurysm wall slows the growth of giant aneurysms. Theoretical predictions of altered hemodynamics will be correlated to experimental values. The methods will include theoretical computational modeling, based on experimental characterization of the aneurysm by MRA, velocity encoded MRI, and CT. Computational patient-specific models will be developed from measured geometry and inlet flow. Data will be retrieved from 15 consecutive patients (5/year) to quantify vascular structure and hemodynamics. About half of the patients will be treated by proximal artery occlusion and half left untreated at the discretion of the surgeon, based on best clinical practices. Aim I: Validating computational model assessment of velocity from MRI data: Aneurysm geometry and inlet flow derived from in vivo imaging prior to intervention will be reproduced in three representative physical models, and the velocity field will be measured and compared to simulations. We hypothesize that the velocity predicted by simulation will be in agreement with measurements in the physical model. Aim II: Theoretical prediction of changes in shear stress and pressure due to treatment: To stimulate aneurysms that had undergone surgical treatment, patient- specific computational models will be modified by simulating occlusion in a proximal feeding artery. The predicted change in flow will be correlated to the change in flow measured by MRI. Aim II: Associating aneurysms growth to biophysical forces: Shear stress and pressure estimated in untreated and treated aneurysms will be compared to measured aneurysm growth. We hypothesize that a change in aneurysm volume will be directly correlated with shear stress and pressure on the wall. The significance of the work is that patient-specific models can predict the result of surgical intervention, and provide clinicians with the ability evaluate emerging methods to treat aneurysms (e.g., stents, coiling).

该项目代表了临床和基础科学家之间的持续合作，以表征作用于动脉病变的生物物理力。建模工具已经发展到可以表征作用于巨大脑梭形动脉瘤的生物物理力的程度。 如果不及时治疗，巨大的动脉瘤可能会在患者的一生中继续扩大。 5 年内死亡或严重发病的风险接近 85%。为了减缓生长，通常会闭塞供血动脉，以期减少血流动力学压力。然而，由于局部壁面剪应力和压力无法直接测量，缺乏定量数据。我们将检验主要假设，即减少动脉瘤壁上的剪切应力和压力的治疗可减缓巨大动脉瘤的生长。血流动力学改变的理论预测将与实验值相关。这些方法将包括基于 MRA、速度编码 MRI 和 CT 对动脉瘤的实验表征的理论计算模型。特定于患者的计算模型将根据测量的几何形状和入口流量开发。将从 15 名连续患者（5 名/年）中检索数据，以量化血管结构和血流动力学。大约一半的患者将接受近端动脉闭塞治疗，另一半则由外科医生根据最佳临床实践酌情不予治疗。目标 I：验证 MRI 数据对速度的计算模型评估：干预前从体内成像得出的动脉瘤几何形状和入口流量将在三个代表性物理模型中重现，并且将测量速度场并与模拟进行比较。我们假设模拟预测的速度将与物理模型中的测量结果一致。目标 II：理论预测治疗引起的剪切应力和压力变化：为了刺激经过手术治疗的动脉瘤，将通过模拟近端供血动脉的闭塞来修改患者特定的计算模型。预测的流量变化将与 MRI 测量的流量变化相关。目标 II：将动脉瘤生长与生物物理力联系起来：将未经治疗和治疗的动脉瘤中估计的剪切应力和压力与测量的动脉瘤生长进行比较。我们假设动脉瘤体积的变化与壁上的剪切应力和压力直接相关。这项工作的意义在于，患者特异性模型可以预测手术干预的结果，并为临床医生提供评估治疗动脉瘤的新兴方法（例如支架、弹簧圈弹簧圈）的能力。