True 4DCT for Quantifying LV Dyssynchrony and Function for Targeting LV Lead Location in CRT

项目摘要/摘要 心脏起搏治疗（CRT）是一种已被证实用于左室功能受损患者的治疗方法， 宽QRS波群然而，约1/3的患者因左室不佳而对CRT无反应 电极导线放置导致持续不同步。没有大型临床试验证明图像来源 参数可以区分应答者和非应答者。观察员内部和供应商之间存在大量 超声心动图参数的差异刺激了对替代成像的研究 方法.我们和其他人已经证明，心脏MRI是一种很好的测量方法， 机械不同步和通过晚期钆增强识别疤痕区域;因此，MRI 可能引导LV电极导线放置，以避免无活性组织和晚期机械损伤的靶区域 activation.不幸的是，大量考虑CRT的患者已有起搏系统，或者 无法进入先进的MRI实验室，严重限制了MR引导的可能性。解决方案： 我们最近开发了一种称为SQUEEZ的新型高分辨率LV功能映射技术， 我们可以通过单次心跳检查从4DCT数据中识别可行的LV起搏目标。然而， 用于测量LV中的不同步的4DCT的精确度是未知的， 如果不进行校正，4DCT可能会损害时间测量。为了达到最佳的时间 分辨率可能，我们提出了一种新的运动校正方案，称为“ResyncCT”，它减少了 CT机架旋转产生的运动伪影。我们的初步结果使我们得出以下假设： 使用SQUEEZ对“ResyncCT”运动校正4DCT图像的分析可用于目标优化 起搏部位，以纠正LV与CRT的不同步。为了验证这一假设，我们将优化 用于测量LV的心脏电影4DCT采集和ResyncCT运动补偿重建 我们将在高度逼真的拟人化3D打印中优化和验证SQUEEZ 以及CRT患者。最终，我们预测CRT反应的准确性将得到检验 回顾性地在一系列CRT患者中，在CRT手术之前获得4DCT数据。为 每个病人，通过分析他们的4DCT数据后ResyncCT和SQUEEZ处理，我们将计算一个新的 LV电极导线部位的“电极导线放置评分”。我们将检验以下假设： 在有反应的患者中（6个月时，收缩末期容积减少> 15%）， 对CRT无反应的患者。

Project Abstract/Summary Cardiac resynchronization therapy (CRT) is a proven treatment for patients with impaired LV function and a wide QRS complex. However, approximately 1/3 of patients do not respond to CRT because of suboptimal LV lead placement yielding persistent dyssynchrony. No large clinical trials have demonstrated that image derived parameters can differentiate responders from non-responders. Significant intra-observer and inter-vendor differences in parameters derived from echocardiography have stimulated the search for alternative imaging methods. We and others have demonstrated that cardiac MRI is an excellent method for measuring mechanical dyssynchrony and identifying regions of scar through late gadolinium enhancement; hence, MRI could possibly guide LV lead placement to avoid non-viable tissue and target regions of late mechanical activation. Unfortunately, a large number of patients considered for CRT have existing pacing systems, or do not have access to advanced MRI laboratories, severely limiting the possibility of MR guidance. The solution: Our recent development of a novel high resolution LV function mapping technique called SQUEEZ now allows us to identify viable LV pacing targets from 4DCT data with a single heartbeat exam. However, the accuracy and precision of 4DCT for measuring dyssynchrony in the LV is unknown and it is clear that motion artifacts in 4DCT may compromise temporal measurements if left uncorrected. In order to achieve the best temporal resolution possible, we propose a novel motion correction scheme called “ResyncCT” which reduces the motion artifacts generated by CT gantry rotation. Our preliminary results lead us to the following hypothesis: the analysis of “ResyncCT” motion-corrected 4DCT images with SQUEEZ can be used to target optimal pacing sites to correct LV dyssynchrony with CRT. In order to validate this hypothesis, we will optimize cardiac cine 4DCT acquisitions and ResyncCT motion compensated reconstruction for measuring LV dyssynchrony, and we will optimize and validate SQUEEZ in highly realistic anthropomorphic 3D printed phantoms and in CRT patients. Ultimately, our accuracy in predicting response to CRT will be tested retrospectively in a series of CRT patients in whom 4DCT data was obtained prior to their CRT procedure. For each patient, by analyzing their 4DCT data after ResyncCT and SQUEEZ processing, we will compute a novel “Lead Placement Score” at the site of their LV lead. We will test the hypothesis that the Lead Placement Score is significantly different in the patients who respond (decrease in End-Systolic Volume > 15% at 6 months) than in those patients who do not respond to CRT.