Ozana Nisan, Lue Niyom, Renna Marco, Robinson Mitchell B, Martin Alyssa, Zavriyev Alexander I, Carr Bryce, Mazumder Dibbyan, Blackwell Megan H, Franceschini Maria A, Carp Stefan A
Department of Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Boston, MA, United States.
Massachusetts Institute of Technology Lincoln Laboratory, Lexington, MA, United States.
Front Neurosci. 2022 Aug 1;16:932119. doi: 10.3389/fnins.2022.932119. eCollection 2022.
Time-domain diffuse correlation spectroscopy (TD-DCS) offers a novel approach to high-spatial resolution functional brain imaging based on the direct quantification of cerebral blood flow (CBF) changes in response to neural activity. However, the signal-to-noise ratio (SNR) offered by previous TD-DCS instruments remains a challenge to achieving the high temporal resolution needed to resolve perfusion changes during functional measurements. Here we present a next-generation optimized functional TD-DCS system that combines a custom 1,064 nm pulse-shaped, quasi transform-limited, amplified laser source with a high-resolution time-tagging system and superconducting nanowire single-photon detectors (SNSPDs). System characterization and optimization was conducted on homogenous and two-layer intralipid phantoms before performing functional CBF measurements in six human subjects. By acquiring CBF signals at over 5 Hz for a late gate start time of the temporal point spread function (TPSF) at 15 mm source-detector separation, we demonstrate for the first time the measurement of blood flow responses to breath-holding and functional tasks using TD-DCS.
时域扩散相关光谱技术（TD-DCS）提供了一种基于直接量化响应神经活动的脑血流量（CBF）变化的新型高空间分辨率功能性脑成像方法。然而，先前TD-DCS仪器提供的信噪比（SNR）仍然是实现功能测量期间解析灌注变化所需的高时间分辨率的一个挑战。在此，我们展示了一种下一代优化的功能性TD-DCS系统，该系统将定制的1064 nm脉冲形状、准变换限制、放大激光源与高分辨率时间标记系统和超导纳米线单光子探测器（SNSPD）相结合。在对六名人类受试者进行功能性CBF测量之前，对均匀和两层脂质体模型进行了系统表征和优化。通过在源-探测器间距为15 mm的时间点扩展函数（TPSF）的晚期门起始时间以超过5 Hz的频率采集CBF信号，我们首次展示了使用TD-DCS测量对屏气和功能性任务的血流反应。
