Development of Thermoacoustic Tomography Brain Imaging

描述(申请人提供)：热声断层扫描(TAT)是一种迅速兴起的超声介导型混合成像方式，有望对诊断成像产生重大影响。TAT在单一的混合模式中结合了高超声分辨率和强烈的微波对比度。人脑成像是一种重要的成像应用，它可以从TAT方法的发展中受益匪浅。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，并且使用笨重且通常不可携带的成像设备。此外，X射线CT使用电离辐射，对需要长期监测脑部疾病或损伤的患者来说不安全。或者，超声检查是一种公认的便携式儿童脑成像手段，但如果在颧骨关闭后使用，其图像质量会严重下降，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方式，将填补现有技术留下的一个重要空白。TAT脑成像的主要技术挑战是补偿颅骨引入TAT测量数据的失真。这项建议的总体目标是通过开发健壮的图像重建方法，使TAT脑成像成为一种实用、有用和高效的脑成像方式，该方法可以解释颅骨诱导的信号失真和其他物理因素。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颅骨形态和成分的信息，我们将开发和研究稳健的TAT成像模型，该模型考虑了颅骨诱导的波前像差和与测量过程相关的其他物理因素的影响。我们将开发重建算法，从与临床有用的测量配置相对应的不完整数据集中获得准确的图像。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。还将进行第一次人体TAT脑成像的活体研究。该项目的具体目标是：(1)开发包含头骨诱导的相位像差影响的成像方法；(2)为实用的脑成像扫描配置开发图像重建算法；(3)在计算机模拟研究中验证TAT脑成像的重建方法；以及(4)评估模体和活体研究中的图像质量。 公共卫生相关性：热声断层扫描脑成像的发展将产生一种强大而有效的新模式，用于监测中风、肿瘤和脑损伤等脑部状况。与现有的高分辨率人脑成像方式相比，它的独特优势包括1)相对低的成本，2)便携，可以在床边或手术室进行近实时的成像研究，3)使用非电离辐射，以及4)测量与现有方法揭示的信息互补的结构和功能信息。

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.