A fast CTOT for mapping whole brain hemodynamic activity in infants

摘要 尽管血氧水平依赖(BOLD)功能磁共振成像(FMRI)被广泛用于脑检查 在成人中激活，技术和后勤挑战经常限制容易地进行功能磁共振成像扫描的能力 和纵向上的，特别是在那些神经发育不良结局风险最高和 发育迟缓。因此，预测是在一般基础上作出的，不能个体化。 以实现最佳管理。功能近红外光谱-漫反射光学层析成像(fNIRS-DOT) 成像有望成为另一种成像技术。目前的fNIRS-DOT成像仅限于皮质 无法询问经常受累的深部结构，如基底节和丘脑 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层析成像(CTOT)，它使用单一的GaAs 增强的ccd探测器阵列成像清醒儿童的全脑血流动力学活动 获取时间。然而，CCD探测器的相当大的读出时间和缓慢的机械切换 光源和探测器的光纤导致了很大的死区时间，延长了测量时间。全副武装 我们的初步临床数据的可行性，我们建议通过适应最近的 快速读出、科学的CMOS探测器阵列及微电子机械系统(MEMS)进展 用于源光纤和收集光纤的新型动态范围控制、自动校准和光交换 以实现亚秒级、动态CTOT映射。这一方法的意义和创新将 是实质性的，因为从来没有一种非侵入性、非侵入性的方法发展到完全 阐明婴儿的全脑血流动力学活动。我们的具体目标是：(1)完善我们的CTOT成像 系统具有单个增强的砷化镓集成探测器、用于源光纤的MEMS光开关和 用于探测器光纤的数字微镜设备，以实现快速动态成像；以及(2)验证CTOTfNIRS 接受BOLD功能磁共振成像的婴儿的衍生血流动力学活动。如果成功，拟议的工作将提供 第一个用于灵敏评估脑血流动力学活动的快速全脑CTOT成像系统 婴儿。在短期内，CTOT图像最终将帮助父母、医生和治疗师最好地计划和 照顾有脑缺陷的儿童，使他们的生活质量随着他们童年的进步而得到优化。

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.