A fast CTOT for mapping whole brain hemodynamic activity in infants

摘要 虽然血氧水平依赖（BOLD）功能性MRI（fMRI）被广泛用于检查大脑 激活，技术和后勤的挑战往往限制了功能磁共振成像扫描的能力容易 在婴儿中，特别是在那些最有可能出现不良神经发育结果的婴儿中， 发育迟缓因此，统计学是在一般基础上作出的，不能个别化 以实现最佳管理。功能近红外光谱-扩散光学层析成像（fNIRS-DOT） 成像有望成为另一种成像技术。目前的fNIRS-DOT成像仅限于皮层 区域和无法询问深层结构，如基底神经节和丘脑，往往涉及 早产儿脑损伤最近，我们报道了一种基于连续波的经颅近红外光学 成像系统，称为基于帽的经颅光学断层扫描（CTOT），采用单一的，砷化镓 增强的CCD检测器阵列，以成像清醒儿童的全脑血流动力学活动， 收购时间。然而，CCD检测器的实质性读出时间和CCD的缓慢机械切换是不可能的。 源和检测器光纤导致大的死区时间，这延长了测量时间。手持 我们的临床可行性的初步数据，我们建议加快测量时间，通过适应最近的 沿着微机电系统（MEMS）的快速读出、科学CMOS检测器阵列的进步 用于新颖的动态范围控制、自动校准以及光源和采集光纤的光学切换 以便实现亚秒级动态CTOT映射。这种方法的意义和创新将 是实质性的，因为从来没有一个非侵入性的，非侵入性的方法被开发出来， 阐明婴儿全脑血流动力学活动。我们的具体目标是：（1）完善CTOT成像 系统具有单个GaAs增强积分检测器、用于源光纤的MEMS光开关和 用于检测器光纤的数字化成像设备，以实现快速、动态成像;以及（2）验证CTOTfNIRS 在婴儿接受BOLD功能磁共振成像衍生的血流动力学活动。如果成功，拟议的工作将提供 第一个快速全脑CTOT成像系统，用于敏感评估脑血流动力学活动， 婴儿。在短期内，CTOT图像最终将帮助父母，医生和治疗师最好的计划， 照顾有脑缺陷的儿童，使他们的生活质量随着童年的发展而得到优化。

Abstract Although Blood Oxygenation Level Dependent (BOLD) functional MRI (fMRI) is widely used to examine brain activation in adults, technical and logistical challenges frequently limit the ability to perform fMRI scans readily and longitudinally in infants, particularly in those at greatest risk for adverse neurodevelopmental outcomes and developmental delays. As a consequence, prognostics are made on general basis and cannot be individualized for optimal management. Functional Near-Infrared Spectroscopy – Diffuse Optical Tomography (fNIRS-DOT) imaging promises to be an alternative imaging technique. The current fNIRS-DOT imaging are limited to cortex regions and unable to interrogate deep structures such as the basal ganglia and thalamus that are often involved premature infant brain injury. Recently, we reported a continuous wave-based transcranial near infrared optical imaging system, called Cap-based Transcranial Optical Tomography (CTOT) that employed a single, GaAs intensified, CCD detector array to image whole brain hemodynamic activity in an awake child with seconds of acquisition time. However, the substantial readout time of the CCD detector and slow mechanical switching of source and detector fiber optics resulted in large dead-times that lengthened measurement times. Armed with our preliminary data of the clinical feasibility, we propose to speed up measurement times by adapting recent advances of fast read-out, scientific CMOS detector arrays along with microelectromechanical systems (MEMS) for novel dynamic range control, automated calibration, and optical switching of source and collection fiber optics in order to enable sub-second, dynamic CTOT mapping. The significance and innovation of this approach will be substantial, as never before has a nonintrusive, noninvasive methodology been developed to completely elucidate whole brain hemodynamic activity in infants. Our specific aims are to: (1) refine our CTOT imaging system with a single, GaAs intensified integrating detector, a MEMS optical switch for source fiber optics and a digital micromirror device for detector fiber optics to enable rapid, dynamic imaging; and (2) validate CTOTfNIRS derived hemodynamic activity in infants undergoing BOLD fMRI. If successful, the proposed work will provide the first, rapid whole brain CTOT imaging system for sensitive assessment of brain hemodynamic activity in infants. In the short term, CTOT images will eventually help parents, physicians and therapists best plan and care for children with brain deficits so that their quality of life is optimized as they progress through childhood.