3D TEE-Aided FEM Biomechanical Modeling for Planning Mitral Valve Repairs

描述（由申请人提供）：大多数心脏手术本质上是重建性的，需要准确了解心脏复杂的三维结构。由于大多数心脏重建手术都是在体外循环下对松弛的空心脏进行的，因此心脏外科医生很难准确预测他们的手术修改在生理条件下的表现。这种不确定性通常会导致手术时间延长、矫正效果欠佳和技术故障，从而对临床结果产生不利影响。尽管心脏成像的最新进展提供了非常准确和详细的心脏结构病理视图，但尚未开发出利用这些功能更好地规划复杂重建手术的方法。 实时三维（3D）经食管超声心动图（TEE）成像提供了传统二维超声心动图不容易实现的心脏上级结构和功能评估。在本提案中，我们试图利用3D TEE成像数据来开发计算生物力学模型，该模型将允许心脏外科医生术前模拟和预测与不同二尖瓣重建选项相关的功能结局。 我们假设：（1）可以开发利用患者特异性3D TEE成像数据的二尖瓣装置的精确计算有限元模型（FEM），以及（2）该生物力学模型的“虚拟”结构修改的血流动力学和功能后果可以用于术前手术计划。我们的具体目标是：具体目标1：我们将进行初步的3D TEE图像分析。我们将改进现有的2D TEE图像分析算法，并将其扩展到3D TEE，以通过自动分割、网格生成、光流估计和动态跟踪来计算患者特定的3D运动和结构信息。具体目标二：我们将开发一个可修改的计算生物力学有限元模型，以准确预测虚拟手术重建导致的二尖瓣关闭行为。具体目标3：我们将仔细验证二尖瓣装置的计算模型。我们将比较计算、预测和观察到的二尖瓣系统运动，以及在涉及人类、体模和猪模型的临床研究中获得的心内血流模式。我们相信，更有预见性的术前计划将促进技术上更合理的心脏和非心脏重建手术，如二尖瓣修复术。 公共卫生相关性：我们建议使用患者特定的3D TEE成像数据来开发二尖瓣装置的精确计算有限元模型（FEM）。我们假设，这种生物力学模型的“虚拟”结构修改的血流动力学和功能后果将有助于二尖瓣修复术的术前手术计划。我们相信，更有预见性的术前计划将促进技术上更合理的重建手术。

DESCRIPTION (provided by applicant): Most cardiac operations are reconstructive by nature and require an accurate understanding of the heart's complex three-dimensional structure. Since most cardiac reconstructive operations are performed on a flaccid empty heart under cardiopulmonary bypass, it is challenging for cardiac surgeons to accurately predict how their surgical modifications will behave under physiologic conditions. This uncertainty often leads to prolonged operations, suboptimal corrections, and technical failures which can adversely impact clinical outcomes. Although recent advances in cardiac imaging have provided remarkably accurate and detailed views of cardiac structural pathologies, a way to exploit these capabilities in better planning complex reconstructive operations has not been developed. Real-time three-dimensional (3D) transesophageal echocardiographic (TEE) imaging provides superior structural and functional assessments of the heart not readily achievable with conventional two-dimensional echocardiography. In this proposal, we seek to exploit 3D TEE imaging data to develop a computational biomechanical model that would permit cardiac surgeons to preoperatively simulate and predict functional outcomes associated with different mitral reconstructive options. We hypothesize that (1) an accurate computational finite-element model (FEM) of the mitral valve apparatus exploiting patient-specific 3D TEE imaging data can be developed and (2) hemodynamic and functional consequences of "virtual" structural modifications of this biomechanical model can be used for the purposes of preoperative surgical planning. Our Specific Aims are: Specific Aim 1: We will perform preliminary 3D TEE image analysis. We will refine our existing 2D TEE image analysis algorithms and extend them to 3D TEE for computing patient-specific 3D motion and structure information through automated segmentation, mesh generation, optical flow estimation, and dynamic tracking. Specific Aim 2: We will develop a modifiable computational biomechanical finite-element model to accurately predict the mitral valve closure behavior resulting from a virtual surgical reconstruction. Specific Aim 3: We will carefully validate our computational model of the mitral valve apparatus. We will compare computed, predicted and observed motion of the mitral valve system, and intracardiac blood flow patterns obtained in clinical studies involving humans, and phantom and porcine models. We believe that more predictive preoperative planning would promote more technically sound cardiac and non-cardiac reconstructive operations such as mitral valve repair. PUBLIC HEALTH RELEVANCE: We propose to use patient-specific 3D TEE imaging data to develop an accurate computational finite- element model (FEM) of the mitral valve apparatus. We hypothesize that hemodynamic and functional consequences of "virtual" structural modifications of this biomechanical model would be useful in the preoperative surgical planning of mitral valve repairs. We believe that more predictive preoperative planning would promote more technically sound reconstructive operations.