Optical Tomography for Cardiac Imaging of Small Animals

描述(由申请人提供)： 我们建议开发一种热声成像设备，能够使用近红外光在小动物如小鼠和大鼠身上制作心脏解剖的轴向图像。我们设想的设备将允许研究人员评估心脏动力学，并研究心脏肥厚和动脉粥样硬化等心血管疾病的转基因模型。最终，我们计划开发一种能够以100-200赫兹的帧速率形成高分辨率图像的设备，足以对小鼠和大鼠的心脏动力学进行成像。这种设备的一个优点是，可以在不需要注射血管增强造影剂的情况下研究心脏动力学。 在第一阶段，我们将设计、建造和测试一个聚焦的圆形换能器阵列，该阵列能够收集足够的热声数据，在单个10 ns的近红外激光脉冲后重建1毫米厚的轴向切片。由于激光脉冲如此之短，在为活体动物成像时，我们应该几乎不会遇到由于心壁运动而产生的模糊。我们希望达到200微米的面内空间分辨率。由于我们目前的数字采集系统(DAS)的限制，在第一阶段，我们将只能以每秒2帧的速度成像。 在第二阶段，我们将展示我们在小鼠和大鼠身上形成心脏动态图像序列的能力。为此，我们将重新设计我们的DAS，使我们能够以高达200赫兹的速率获取动态图像序列。我们还将采用定制设计的、可调谐的近红外激光器，能够以200赫兹的频率脉冲。在这一阶段，我们将开发多层成像协议，以形成心脏跳动的3D图像。

DESCRIPTION (provided by applicant): We propose to develop a thermoacoustic-imaging device capable of making axial images of the cardiac anatomy in small animals such as mice and rats using near infrared light. The device we envision will allow researchers to assess cardiac dynamics and to study transgenic models of cardiovascular disease, such as cardiac hypertrophy and atherosclerosis. Ultimately we plan to develop a device capable of forming high-resolution images at a frame rate of 100 - 200 Hz, sufficient to image the cardiac dynamics of mice and rats. One advantage offered by such a device is that cardiac dynamics can be studied without the need for injecting vascular-enhancing contrast material. In Phase I, we will design, construct and test a focused, circular transducer array capable of collecting sufficient thermoacoustic data to reconstruct a 1-mm-thick axial slice following a single, 10-ns pulse of near infrared laser light. Because the laser pulse is so short, we should encounter virtually no blur due to heart-wall motion when imaging live animals. We hope to achieve in-plane spatial resolution of < 200 microns. Due to limitations of our present digital acquisition system (DAS), we will only have the capability of forming images at 2 frames per second during Phase I. In Phase II we will demonstrate our ability to form dynamic image sequences of the heart in mice and rats. To this end we will redesign our DAS to allow us to acquire dynamic image sequences at rates as high as 200 Hz. We will also incorporate a custom-designed, tunable, near-infrared laser capable of pulsing at 200 Hz. In this phase we will develop multi-slice imaging protocols to form 3-D images of the beating heart.