Acoustically Active Catheter for Ultrasound-Guided Intramyocardial Injections

 描述（由申请人提供）：微创干预正在迅速兴起。在通过经内膜注射的梗死的细胞治疗中，需要朝向心肌内目标的高度空间准确的解剖引导、左心室（LV）壁运动的测量以及存活心肌的识别。虽然一些成像方法提供了很好的解剖学检查或机电图，超声心动图（回声）是唯一一个可以联合收割机结合所有上述要求到一个便携式，非电离和成本效益的指导系统。这种全面的解决方案是非常需要的，但目前并不存在。 作为回应，我们提出了一种创新的超声导航解决方案，基于我们的声学有源导管（AAC）原型，其尖端装有压电晶体。晶体以特定频率振动，因此，AAC尖端充当声学“信标”，通过脉冲波（PW）多普勒采样窗口明确识别和空间定位。因此，PW多普勒用于一种新的应用：它在常规（灰度）扫描中跟踪AAC头端，并能够将头端引导到所需的解剖目标。不需要修改传统的超声成像仪。 我们的初步工作已经证明了所提出的导航原理，并证明了其空间定位精度。在当前应用中，现有的功能性AAC原型将用作 一个平台，用于进一步研究微创手术的声学导航，推进基于导管的心肌内注射的深度控制，以及确定心肌内药物给药的疗效。我们还将利用我们在声学，体外和体内（开胸和闭胸）猪实验，参考测量的声测仪器和最先进的超声技术的理论工作。本申请的目的如下。在目标1中，我们将通过实施AAC头端的彩色多普勒标记来推进导航功能，从而实现导管头端的实时双平面可视化和3D跟踪。在目标2中，我们将通过开发和测试用于针插入深度测量的超声方法来解决心肌内注射的准确性和安全性。在目标3中，我们将使用我们先前的LV功能的局部生化（非破坏性）抑制模型，并通过从心脏内引导的注射AAC来测试心肌内药剂递送的功效。我们的团队和两位主要研究者在心脏介入、超声心动图、心血管模型和振动声学方面的互补专业知识有助于实现这些目标。该研究是有意义的，因为特定的局部声源与多普勒跟踪的组合消除了使传统超声图像引导介入复杂化的伪影。

 DESCRIPTION (provided by applicant): Minimally invasive interventions are rapidly emerging. In cell therapy of infarction by transendocardial injections, highly spatially accurate anatomical guidance towards an intramyocardial target, measurements of left ventricular (LV) wall motion, and identification of viable myocardium are required. While some imaging methods provide excellent anatomical depictions or electromechanical maps, echocardiography (echo) is the only one that could combine all the above requirements into a portable, nonionizing, and cost-effective guidance system. Such a comprehensive solution is highly desired, but currently does not exist. In response, we propose an innovative ultrasound navigation solution based on our acoustically active catheter (AAC) prototype, which has its tip fitted with a piezoelectric crystal The crystal vibrates at a specific frequency, and as a result, the AAC tip then acts as an acoustic "beacon," which is unambiguously identified and spatially localized by a pulsed-wave (PW) Doppler sample window. Thus, PW Doppler is used in a new application: It tracks the AAC tip within conventional (grayscale) scans and enables guidance of the tip to a desired anatomical target. There is no need to modify the conventional ultrasound imager. Our preliminary work has proven the proposed navigation principle and demonstrated its spatial targeting accuracy. In the current application, the existing functional AAC prototype will serve as a platform for further investigations of acoustic navigation of minimally invasive procedures, advancement of depth control of catheter-based intramyocardial injections, and determination of the efficacy of intramyocardial agent administrations. We will also capitalize on our theoretical work in acoustics, in vitro and in vivo (open-chest and closed-chest) pig experiments, sonometric instrumentation for reference measurements, and state of the art ultrasound technologies. The application is organized to the following aims. In aim 1, we will advance the navigation function by implementing a color Doppler marker of the AAC tip, allowing real-time biplane visualization and 3D tracking of the catheter tip. In aim 2, we will address intramyocardial injection accuracy and safety by developing and testing a sonometric approach for needle insertion depth measurement. In aim 3, we will use our previous model of local biochemical (nondestructive) inhibition of LV function and test efficacy of intramyocardial agent delivery by an injection AAC guided from within the heart. Our team and complementary expertise of the two principal investigators in cardiac interventions, echo, cardiovascular models, and vibroacoustics are conducive to accomplishing these aims. The research is significant because the combination of the specific localized acoustic source with Doppler tracking alleviates artifacts complicating image-guided intervention with conventional ultrasonography.