Stork: Diffuse Optical Brain Imaging

AMIR H GANDJBAKHCHE (? to ?) Diffuse Optical Brain Imaging. Amount: $1975524

功能和结构光学脑成像

Abstract

Diffuse Optical Imaging (DOI) allows us access to the hemodynamic response in tissue. It has been shown that we can, by detecting the effects of neuro-vascular coupling, relate this to functional events in the brain. Existing technologies in DOI are limited by a number of factors, but most strongly by the absence of viable clinical applications where they may be applied. Originally we were targeting young epilepsy sufferers who have had radical hemispherectomies, and veterans (at the upper end of the pediatric population) with penetrating Traumatic Brain Injury (TBI). This year we have, through our continuing outreach, identified a third key population, Autistic Spectrum Disorder (ASD) patients. These patients are low-functioning and typically pediatric populations. Over the course of the 2010 fiscal year we have developed our collaborations, secured a patent for one of our novel instrument ideas, and had several presentations accepted at the Society for Neuroscience. We are assembling a variety of instruments both in the lab (through our collaborators at Drexel) and at our other collaborators lab in Georgetown. The latter is a DOI instruments combined with EEG. Clinically we are now commencing initial testing with healthy volunteers. We are awaiting the protocol number for our newly approved IRB through NICHD to begin testing on our prototype systems here at NICHD. To conduct functional brain imaging experiments, we have developed a number of cognitive tasks (event complexity judgment task, a verbal working memory task, and a multi-task) in E-prime software. The timing of the presentation of each stimulus will be accurately recorded which will be used in data analysis. We have also worked on data processing techniques to extract the brain hemodynamic response from the optical data. Initial experiments were performed using the event complexity task in collaboration with Georgetown. Principal component analysis (PCA) and independent component analysis (ICA) have been applied to the data to remove the noise and motion artifact components. Corresponding extracted hemodynamic responses validate the technique as they correlate with the results of previous fMRI studies. In addition, with collaborators at NIMH, we are currently discussing suitable functional studies useful to ASD patients, and once we have initial data on healthy volunteers, we will produce a study on ASD patients, either in a young adult or pediatric population. Theoretically we are currently working on a variety of approaches for handling the shortcomings of current DOI techniques. Our primary focus at the moment is addressing the issue of atlasing and registration for DOI. This area is a hot topic of research but unlike MRI where Talairach and MNI atlases have become de facto standards DOI has no such standard approach. Part of this is the absence of certainty in reconstruction methodologies and part is the issue of co-registering data. We have been working on better quantitation and localization of optical signals as part of the project. Our current focus though has been on readdressing atlasing and registration by mapping data to a different co-ordinate basis. We are currently finishing a paper based on the principle of moving optical data into a polar/spherical basis (which is more natural to its sensitivity and resolution). By doing so we can directly register data in the 3D volume based upon an effective registration of the 2D surface manifold. This method will also combine with work we are developing on describing the sensitivity of optical imaging in fractal dimensions. This will combine to allow us to evolve much more sophisticated probabilistic functional atlases of the human brain for DOI. Our collaboration with NINDS continues to develop a new fiber based imager to add to our selection of devices for comparison and contrast of DOI techniques. Also we have a fully miniaturized system under development in association with our collaborators at Drexel. Initial designs for optical transmitter and receiver have been implemented and the functionality of each module has been verified experimentally. Quad vertical cavity surface emitting laser diodes are used in the transmitter, and the system takes advantage of Gradient-Index (GRIN) lens technology to achieve excellent optical collection efficiency. We are currently working on the integration of the modules. These projects will combine to produce fully wearable DOI for Near Infrared functional imaging. Our theoretical research is also examining motion artifact as a signal instead of noise. Initial results suggest that if we can model the motion of our imaging system relative to the subject via the helmet interface (a process being worked on by our instrumentalists), we should further be able to enhance optical signals to an unprecedented level of accuracy and quantitation in the field. Finally we have submitted and received an initial patent to a novel instrument design intended to detect hematomas. It is designed to assist in the triage of patients with all forms of TBI. The ability to identify and triage for the presence of hematoma would greatly increase efficiency of use of more expensive and limited access systems such as CT and MRI. Currently we are working on the full theoretical model to test the design. Once complete this model will allow us to progress rapidly to an initial prototype. The current status-quo in NIR modeling is also being challenged by this project. Initial results indicate that the paradigm that more sources and detectors at higher density is better for imaging is being challenged. Initial results from this project suggest there will be a fine balance between improved instrumentation and error introduced by the computational boundaries of modeling.

漫射光学成像(DOI)使我们能够获得组织中的血液动力学反应。已经表明,通过检测神经血管耦合的影响,我们可以将其与大脑中的功能事件联系起来。 DOI中的现有技术受到许多因素的限制,但最强烈的原因是缺乏可行的临床应用。最初我们的目标是那些患有根治性半球切除术的年轻癫痫患者,以及具有穿透性创伤性脑损伤(TBI)的退伍军人(在儿科人群的上端)。今年,通过我们的持续推广,我们确定了第三个关键人群,即自闭症谱系障碍(ASD)患者。这些患者功能低下,通常是儿科人群。在2010财年的过程中,我们开展了合作,为我们的一种新型仪器创意获得了专利,并在神经科学学会接受了多次演示。我们正在实验室(通过我们在Drexel的合作者)和我们在乔治城的其他合作实验室组装各种仪器。后者是结合脑电图的DOI仪器。临床上我们现在开始与健康的志愿者进行初步测试。我们正在等待我们新批准的IRB的协议号,通过NICHD在NICHD开始测试我们的原型系统。为了进行功能性脑成像实验,我们在E-prime软件中开发了许多认知任务(事件复杂性判断任务,口头工作记忆任务和多任务)。将准确记录每个刺激的呈现时间,这将用于数据分析。我们还致力于数据处理技术,从光学数据中提取脑血流动力学反应。使用事件复杂性任务与Georgetown合作进行初始实验。主成分分析(PCA)和独立成分分析(ICA)已应用于数据,以消除噪声和运动伪影成分。相应的提取血液动力学反应证实了该技术,因为它们与先前的fMRI研究结果相关。此外,与NIMH的合作者,我们目前正在讨论对ASD患者有用的合适功能研究,一旦我们获得了健康志愿者的初步数据,我们将在年轻成人或儿科人群中开展ASD患者的研究。从理论上讲,我们目前正在研究各种方法来处理当前DOI技术的缺点。我们目前的主要重点是解决DOI的地图集和注册问题。这个领域是研究的热门话题,但不像MRI那样Talairach和MNI地图集成为事实上的标准,DOI没有这样的标准方法。部分原因是重建方法缺乏确定性,部分原因是共同注册数据的问题。作为项目的一部分,我们一直致力于更好地定量和定位光学信号。我们目前的重点是通过将数据映射到不同的坐标来重新寻址和注册。我们目前正在完成一篇论文,其基于将光学数据移动到极性/球形基础的原理(其灵敏度和分辨率更自然)。通过这样做,我们可以基于2D表面流形的有效配准直接在3D体积中记录数据。这种方法还将结合我们正在开发的描述光学成像在分形维数中的灵敏度的工作。这将结合起来,使我们能够为DOI演化更为复杂的人脑大脑概率功能图谱。我们与NINDS的合作继续开发新的基于光纤的成像仪,以添加到我们选择的设备中,用于DOI技术的比较和对比。此外,我们还与Drexel的合作伙伴共同开发了一个完全小型化的系统。 已经实现了光发射器和接收器的初始设计,并且已经通过实验验证了每个模块的功能。在发射器中使用四个垂直腔表面发射激光二极管,并且该系统利用梯度指数(GRIN)透镜技术来实现优异的光学收集效率。我们目前正致力于模块的集成。这些项目将结合起来,为近红外功能成像生成完全可穿戴的DOI。我们的理论研究还将运动伪影检测为信号而不是噪声。初步结果表明,如果我们可以通过头盔界面模拟我们的成像系统相对于受试者的运动(我们的乐器主义者正在进行的过程),我们应该进一步能够将光学信号增强到前所未有的准确度和定量水平在该领域。最后,我们提交并获得了一项旨在检测血肿的新型仪器设计的初始专利。它旨在帮助所有形式的TBI患者进行分类。识别和分类血肿存在的能力将大大提高使用更昂贵和有限的访问系统(例如CT和MRI)的效率。目前,我们正在研究完整的理论模型来测试设计。一旦完成,该模型将允许我们快速进入初始原型。 NIR建模的当前现状也受到该项目的挑战。初步结果表明,更高密度的更多光源和探测器更适合成像的范例正受到挑战。该项目的初步结果表明,改进的仪器和建模的计算边界引入的误差之间将存在良好的平衡。

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