Development of Thermoacoustic Tomography Brain Imaging

描述（由申请人提供）：热声断层扫描（TAT）是一种快速兴起的超声介导的混合成像方式，有望对诊断成像产生重大影响。TAT在单一混合模式下结合了高超声分辨率和强微波对比度。人脑成像是一种重要的成像应用，它可以从TAT方法的发展中获益良多。现有的高分辨率人脑成像方式，如x射线计算机断层扫描（CT）和磁共振成像（MRI），价格昂贵，使用体积庞大且通常不可携带的成像设备。此外，x射线CT使用电离辐射，对于需要长时间监测脑部疾病或损伤的患者是不安全的。另外，超声是一种成熟的便携式儿童脑成像方式，但在关闭囟门后使用时，其图像质量严重下降，因此对成人成像无效。TAT脑成像方法的发展将绕过这些限制，并产生一种强大的新脑成像模式，将填补现有技术留下的重要空白。TAT脑成像的主要技术挑战是补偿由颅骨引入的TAT测量数据的畸变。本提案的总体目标是通过开发健壮的图像重建方法，可以解释头骨引起的信号失真和其他物理因素，使TAT脑成像成为一种实用、有用和高效的脑成像方式。通过使用从先前获得的辅助图像数据或从TAT测量数据本身获得的有关头骨形态和组成的信息，我们将开发和研究用于TAT的鲁棒成像模型，该模型考虑了头骨引起的波前像差和其他与测量过程相关的物理因素的影响。我们将开发重建算法，从不完整的数据集中获得准确的图像，这些数据集对应于临床有用的测量配置。所开发的方法将在计算机模拟和实验研究中进行系统的评估。还将进行首次人体TAT脑成像的体内研究。该项目的具体目标是：(1)开发包含头骨引起的相位像差影响的成像方法；(2)开发适用于实际脑成像扫描配置的图像重建算法；(3)在计算机模拟研究中验证TAT脑成像重建方法；(4)评估幻影和活体研究中的图像质量。

DESCRIPTION (provided by applicant): Thermo acoustic tomography (TAT) is a rapidly emerging ultrasound-mediated hybrid imaging modality that promises to have a major impact on diagnostic imaging. TAT combines high ultrasonic resolution and strong microwave contrast in a single hybrid modality. Human brain imaging represents an important imaging application that can benefit tremendously by the development of TAT methods. Existing high-resolution human brain imaging modalities such as X-ray computed tomography (CT) and magnetic resonance imaging (MRI) are expensive and employ bulky and generally non-portable imaging equipment. Moreover, X-ray CT employs ionizing radiation and is unsafe for patients who need long time monitoring of brain diseases or injuries. Alternatively, ultrasonography is an established portable pediatric brain imaging modality, but its image quality degrades severely when employed after the closure of the fontanels and therefore is not effective for imaging adults. The development of TAT brain imaging methods would circumvent these limitations and result a powerful new brain imaging modality that would fill an important void left by the available techniques. The major technical challenge in TAT brain imaging is to compensate for the distortion introduced into the TAT measurement data by the skull. The broad objective of this proposal is to make TAT brain imaging a practical, useful, and highly effective brain imaging modality by developing robust image reconstruction methods that can account for skull-induced signal distortion and other physical factors. By use of information regarding the skull morphology and composition obtained from previously acquired adjunct image data, or alternatively from the TAT measurement data themselves, we will develop and investigate robust imaging models for TAT that account for the effects of skull-induced wave front aberrations and other physical factors related to the measurement process. We will develop reconstruction algorithms for obtaining accurate images from incomplete data sets that correspond to clinically useful measurement configurations. The developed methods will be systematically evaluated in computer-simulation and experimental studies. The first in vivo study of human TAT brain imaging will also be conducted. The specific aims of the project are: (1) To develop imaging methodologies that incorporate the effects of skull-induced phase aberrations; (2) To develop image reconstruction algorithms for practical brain imaging scanning configurations; (3) To validate the reconstruction methods for TAT brain imaging in computer-simulation studies; and (4) To assess image quality in phantom and in-vivo studies. PUBLIC HEALTH RELEVANCE: The development of thermo acoustic tomography brain imaging will yield a powerful and effective new modality for monitoring brain conditions such as strokes, tumors, and brain injuries. Its specific advantages over existing high-resolution human brain imaging modalities include 1) relatively low-cost, 2) portability that would permit near real-time imaging studies at bedside or in operating rooms, 3) use of non-ionizing radiation, and 4) measurement of structural and functional brain information that is complementary to that revealed by existing methods.