Comprehensive analysis of endocardial strain using 4DCT data

项目摘要 在过去的十年里，基于微创经导管的手术已经作为一种选择的治疗方法出现。 瓣膜疾病患者作为风险更高的心内直视手术的替代方案，特别是在高危患者 多发性合并症带来的手术风险。随着技术的进步和临床结果的成功 正如最近的临床试验所证明的那样，风险较低的患者可能有资格接受这些手术 经导管行主动脉瓣膜置换术。非侵入性成像，这支持了经导管的发展 通过提供出色的术前计划进行干预，也可以对患者分层有用。 基于可量化的预后参数。例如，经导管二尖瓣置换术(TMVR)是一种 相对较新的治疗二尖瓣反流(MR)的微创方法；然而，其对左心室的影响 (LV)功能尚未被表征。此外，因左心室而继发MR的患者 缺血性或特发性心肌病所致的重塑可能有很大一部分心肌 已经出现功能障碍，这需要对左心室功能进行区域性表征。 建议的项目旨在评估MR和植入生物瓣膜对LV的净影响。 通过识别心肌运动前和1个月前的无动力、运动障碍、运动减退和正常区域的功能 使用非侵入性单次心跳4DCT衍生指标的微创瓣膜置换术后。它是 假设正常和异常组织的比例和空间分布将与能力相关 介入治疗后恢复左心室功能。心内膜纵向应变，周向应变， 旋转将与传统的全球指标进行比较，如每搏量和射血分数。此外, 我们将研究生物二尖瓣装置和锚定系统的位置对 通过对手术前后的心脏形态进行统计建模，了解心脏的重塑过程。 为了用估计的置信度区间将局部心肌功能表征为正常或异常， 4DCT衍生的测量工具的精度将被量化。该项目旨在评估效果。 空间分辨率、时间分辨率、信噪比和患者心率对精度的影响 心功能指标。此外，建议的4DCT衍生指标将在符合以下条件的受试者中进行验证 在同一天内接受MRI标记和4DCT检查。

Project Summary Minimally invasive transcather-based procedures have emerged over the past decade as a therapy for selected patients with valvular disease as an alternative to riskier open-heart surgery, particularly in patients with high surgical risk due to multiple comorbidities. As the technology improves and successful clinical outcomes increase, lower-risk patients are likely to be eligible for these procedures as demonstrated by recent clinical trials for transcather aortic valve replacement. Noninvasive imaging, which has supported the growth of transcather interventions by providing excellent preprocedural planning, could also become useful for stratifying patients based on quantifiable prognostic parameters. For example, transcatheter mitral valve replacement (TMVR) is a relatively new minimally invasive procedure to treat mitral regurgitation (MR); however, its effect on left ventricular (LV) function has not yet been characterized. In addition, patients with secondary MR as a result of left ventricular remodeling due to ischemic or idiopathic cardiomyopathy can have a large portion of their myocardium which is already dysfunctional which requires regional characterization of LV function. The proposed project aims to evaluate the net effect of MR and implantation of the bioprosthetic valve on LV function by identifying akinetic, dyskinetic, hypokinetic and normal regions of myocardium before and 1-month post minimally invasive valve replacement using noninvasive single heartbeat 4DCT-derived metrics. It is hypothesized that the fraction and spatial distribution of normal vs. abnormal tissue will correlate with the ability of the LV to recover post intervention. Regional maps of endocardial longitudinal strain, circumferential strain, and rotation will be compared to traditional global metrics such as stroke volume and ejection fraction. In addition, we will investigate the effect of the position of the bioprosthetic mitral valve device and anchoring system upon the remodeling process of the LV by performing statistical shape modeling pre and post procedure. In order to characterize regional myocardial function as normal or abnormal with estimated confidence intervals, the precision of the 4DCT-derived measurement tools will be quantified. This project aims to evaluate the effect of spatial resolution, temporal resolution, the signal-to-noise ratio, and the patient’s heart rate on the precision of myocardial function metrics. In addition, the proposed 4DCT-derived metrics will be validated in subjects who undergo both MRI tagging and 4DCT exams within the same day.