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

项目摘要/摘要 心脏再同步化治疗(CRT)是一种已被证实的治疗左心功能受损和 宽广的QRS波群。然而，大约三分之一的患者对CRT没有反应，因为LV不理想 引线放置会导致持续的不同步。还没有大型临床试验证明图像源自 参数可以区分响应者和非响应者。重要的观察者内部和供应商间 超声心动图参数的差异刺激了人们对替代成像的研究 方法：研究方法。我们和其他人已经证明，心脏核磁共振是一种很好的测量方法 机械不同步和通过晚期Gd增强识别瘢痕区域；因此，MRI 可能会指导LV导联的放置，以避免晚期机械损伤的非活性组织和靶区 激活。不幸的是，许多考虑接受CRT的患者都有或确实有起搏系统。 无法获得先进的核磁共振实验室，严重限制了磁共振指导的可能性。解决方案： 我们最近开发的一种称为挤压Z的新的高分辨率LV函数映射技术现在允许 美国通过一次心跳检查从4DCT数据中识别可行的LV起搏靶点。然而，准确率 而4DCT测量左室不同步的精度尚不清楚，显然运动伪影在 如果不进行校正，4DCT可能会影响时间测量。为了达到最佳的时间性 为了提高分辨率，我们提出了一种称为“ResyncCT”的新的运动校正方案，该方案降低了 CT机架旋转生成的运动伪影。我们的初步结果使我们得出以下假设： 用SqueeZ对运动校正后的4DCT图像进行“ResyncCT”分析可用于目标优化 起搏部位纠正左心室与CRT的不同步。为了验证这一假设，我们将优化 心脏电影4DCT采集及运动补偿重建测量LV 不同步，我们将在高度逼真的拟人3D打印中优化和验证SqueeZ 幻影和CRT患者。最终，我们预测CRT反应的准确性将受到考验 对一系列CRT患者在接受CRT手术前获得的4DCT数据进行回顾性研究。为 每个患者，通过分析他们的4DCT数据经过ResyncCT和挤压Z处理后，我们将计算出一个新的 在他们的LV导联部位的“导联定位分数”。我们将测试Lead Placement分数的假设 在有反应的患者中(6个月时收缩末期容量下降15%)与 在CRT无效的患者中。

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.