3D Ultrasound Current Source Density Imaging for Treatment of Heart Arrhythmia

描述（由申请人提供）：复发性心律失常是一种严重的健康问题，影响超过400万美国人，占所有心脏病相关死亡的20%。在药物治疗无效的晚期病例中，心律失常通常采用消融或消融治疗。心内消融术纠正耐药心律失常依赖于心脏激动波的准确标测。尽管用于治疗心律失常的介入性心脏手术在全球取得了成功，但是心脏的电生理（EP）标测具有显著的局限性;例如，复杂且昂贵的过程易于产生图像配准误差，对于识别瞬时心律失常无效，并且具有相对差的空间分辨率（5-10 mm）。为了克服几个限制，并显着改善EP映射程序，我们提出了一种新的模式，实时成像的电流和生物电位在心脏。因此，该项目将开发超声电流源密度成像（UCSDI），以大大增强和促进心脏的EP标测。UCSDI基于局部压力和电阻率之间的声电（AE）相互作用来远程检测组织中的电流。正如我们在各种制备中所证明的那样，通过组织的超声产生接近超声频率并与局部电流密度成比例的电压调制（AE信号）。UCSDI将通过以下方式促进心律失常和其他心脏疾病消融治疗期间的图像引导：1）心脏中电流和心脏电位的直接3D成像; 2）主要由超声焦点大小确定的增强空间分辨率; 3）与脉冲回波超声（超声心动图）自动配准，用于将电流图与心脏解剖结构和运动叠加。以下具体目标是检验这一假设的核心。SA.1.增强UCSDI系统硬件和软件SA.2.确定灵敏度和分辨率SA的基本限值。3.将UCSDI系统与商用心内导管连接该项目将显着改进我们现有的UCSDI系统，确定使用UCSDI进行心脏激动波EP标测的灵敏度和空间分辨率的限制，并证明使用临床心内导管的可行性。成功的结果将导致5年的更新，重点是体内研究和转移到手术室。公共卫生相关性：该提案将开发3D超声电流源密度成像（UCSDI），这是一种基于超声和导电组织之间相互作用的新模式，用于绘制心脏的电活动。优化的成像系统将极大地促进和增强用于治疗心律失常的心脏的电生理标测。

DESCRIPTION (provided by applicant): Recurrent cardiac arrhythmia is a serious health concern affecting more than 4 million Americans and accounts for 20% of all deaths related to heart disease. In advanced cases when drug therapy is ineffective, arrhythmias are often treated with resynchronization or ablation therapy. Intracardiac ablation procedures to correct drug-resistant arrhythmias depend on accurate maps of the cardiac activation wave. Despite global success of interventional cardiac surgery for treatment of arrhythmias, electrophysiological (EP) mapping of the heart has significant limitations; for example, the complex and expensive procedure is prone to image registration errors, not effective for identifying transient arrhythmias, and has relatively poor spatial resolution (5-10 mm). To overcome several limitations and dramatically improve EP mapping procedures, we propose a novel modality for real-time imaging of current flow and biopotentials in the heart. As such, this project would develop Ultrasound Current Source Density Imaging (UCSDI) to greatly enhance and facilitate EP mapping of the heart. UCSDI is based on an acoustoelectric (AE) interaction between local pressure and resistivity to remotely detect current flow in tissue. As we have demonstrated in a variety of preparations, ultrasound passing through tissue generates a voltage modulation (the AE signal) close to the ultrasound frequency and proportional to the local current density. UCSDI would facilitate image guidance during ablation treatment of arrhythmias and other cardiac disorders through 1) direct 3D imaging of current flow and cardiac potentials in the heart; 2) enhanced spatial resolution determined primarily by the size of the ultrasound focus; and 3) automatic co-registration with pulse echo ultrasound (echocardiograms) for overlaying current flow maps with cardiac anatomy and motion. The following specific aims are central for testing this hypothesis. SA.1. Enhance UCSDI system hardware and software SA.2. Determine fundamental limits of sensitivity and resolution SA.3. Interface UCSDI system with commercial intracardiac catheter This project would dramatically improve our existing UCSDI system, identify limits of sensitivity and spatial resolution for EP mapping of the cardiac activation wave using UCSDI, and demonstrate feasibility using a clinical intracardiac catheter. A successful outcome would lead to a 5-year renewal focusing on in vivo studies and translation to the operating room. PUBLIC HEALTH RELEVANCE: This proposal will develop 3D ultrasound current source density imaging (UCSDI), a new modality based on an interaction between ultrasound and conductive tissue, to map electrical activity in the heart. An optimized imaging system would greatly facilitate and enhance electrophysiological mapping of the heart for treatment of arrhythmias.