High spatial resolution evaluation of subclinical regions of myocardial dysfunction in adult patients with tetralogy of Fallot

项目摘要 手术修复法洛四联症(RTOF)已导致良好的长期存活率，但rTOF幸存者往往 经历残留和进行性右室(RV)功能障碍，给这些患者带来不利的负担 晚年的心脏事件。鉴于不断增长的人口，临床上迫切需要一种技术来指导 病人管理。CT可以用来可靠地获得成人rTOF患者的整体功能测量，但 目前还没有对区域功能障碍进行量化。应力性评估可以受到脑室变化的限制。 几何构型和不同步收缩，这两种情况在rTOF患者中都很常见。心肌做功(MW) -临床上测量的脑室压力-应变环区域-可以克服这种担忧，因为它是密切相关的 与心肌灌注有关，并已被证明更独立于负荷条件。然而， 室压测量不能捕捉到心肌应力的区域性异质性， 这一近似值的影响尚未被探讨。此外，微波检测早期轮状病毒的临床应用价值 CT检查的rTOF患者的功能障碍尚未得到证实。 我们最近开发了MWCT，这是一种结合局部心内膜应变的局部MW的估计 心电门控CT(RSCT)和右室压力波形的测量。拟议的项目旨在 研究MWCT作为捕捉成人rTOF患者亚临床功能障碍区域的定量工具。这个 MWCT检测区域功能障碍的能力将与有限- 局部心内膜应激和RSCT的单元模型。这一目标将建立简单的、基于压力的 MWCT估计作为表征区域房车性能的有效工具。此外，这一目标将与 有限元方法，并建立了一种测量心肌内膜应力-应变环面积的方法 MWCT管道。横断面CT成像将评估MWCT表现良好的区域是否符合 心肺运动试验(CPET)的结果比单独运动更好。此外，通过以下方式进行纵向评估 将进行功能分级和CT成像以评估心内膜不协调的数量 (区域工作和应变测量之间的不一致)对应于症状恶化 和功能障碍。这一目标将证明捕捉早期功能障碍将改善临床 通过在全球变化之前检测不利的重塑来进行护理。这项提议的长期目标是 将CT建立为评估区域RV功能的可行方法，并开发强大的量化工具 早期发现所有rTOF幸存者的功能障碍。

Project Summary Surgical repair of tetralogy of Fallot (rTOF) has led to excellent long-term survival, yet rTOF survivors often experience residual and progressive right ventricular (RV) dysfunction that burden these patients with adverse cardiac events later in life. Given this growing population, there is a strong clinical need for techniques to guide patient management. CT can be used to robustly obtain global measures of function in adult rTOF patients, but regional dysfunction is not currently quantified. Strain evaluation can be limited by changes in ventricular geometry and dyssynchronous contraction, both of which are common in rTOF patients. Myocardial work (MW) – clinically measured as the ventricular pressure-strain loop area – can overcome this concern, as it is closely related to myocardial perfusion and has been shown to be more independent of loading conditions. However, ventricular pressure measurements do not capture regional heterogeneities in myocardial stress and the impact of this approximation has not been explored. Further, the clinical utility of MW to detect early RV dysfunction in rTOF patients with CT has not been established. We have recently developed MWCT, an estimate of regional MW that combines regional endocardial strain measurements from ECG-gated CT (RSCT) and RV pressure waveforms. The proposed project aims to investigate MWCT as a quantitative tool to capture regions of subclinical dysfunction in adult rTOF patients. The ability for MWCT to detect regional dysfunction will be compared to advanced MW estimates derived from finite- element models of regional endocardial stress and RSCT. This aim will establish the simple, pressure based MWCT estimate as an effective tool for characterizing regional RV performance. Further, this aim will compare FE methods and establish an approach to measure MW as the endocardial stress-strain loop area within our MWCT pipeline. Cross-sectional CT imaging will assess whether well-performing areas on MWCT agree with cardiopulmonary exercise test (CPET) findings better than strain alone. Additionally, longitudinal evaluation via functional class and CT imaging will be performed to assess whether the amount of discordant endocardium (disagreement between regional work and strain measurements) corresponds with worsening symptomatology and dysfunction respectively. This aim will demonstrate that capturing early dysfunction will improve clinical care by detecting adverse remodeling prior to global changes. The long-term goal of this proposal is to establish CT as a feasible method for evaluating regional RV function and develop robust quantitative tools for early detection of dysfunction in all rTOF survivors.