Abstract：
Recent advances in functional ultrasound imaging (fUS) and photoacoustic tomography (PAT) offer powerful tools for studying brain function. Complementing each other, fUS and PAT, respectively, measure the cerebral blood flow (CBF) and hemoglobin concentrations, allowing synergistic characterization of cerebral hemodynamics. Here, cross-ray ultrasound tomography (CRUST) and its combination with PAT are presented. CRUST employs a virtual point source from a spherically focused ultrasonic transducer (SFUST) to provide widefield excitation at a 4-kHz pulse repetition frequency. A full-ring-shaped ultrasonic transducer array whose imaging plane is orthogonal to the SFUST\'s acoustic axis receives scattered ultrasonic waves. Superior to conventional fUS, whose sensitivity to blood flow is angle-dependent and low for perpendicular flow, the crossed transmission and panoramic detection fields of CRUST provide omnidirectional sensitivity to CBF. Using CRUST-PAT, the CBF, oxygen saturation, and hemoglobin concentration changes of the mouse brain during sensory stimulation are measured, with a field of view of ≈7 mm in diameter, spatial resolution of ≈170 µm, and temporal resolution of 200 Hz. The results demonstrate CRUST-PAT as a unique tool for studying cerebral hemodynamics.
摘要：
功能超声成像（fUS）和光声断层扫描（PAT）的最新进展为研究脑功能提供了强大的工具。互相补充,FUS和PAT,分别,测量脑血流量（CBF）和血红蛋白浓度，允许脑血流动力学的协同表征。这里,介绍了交叉射线超声断层成像（CRUST）及其与PAT的结合。CRUST采用来自球形聚焦超声换能器（SFUST）的虚拟点源，以4kHz脉冲重复频率提供宽场激励。成像平面与SFUST的声轴正交的全环形超声换能器阵列接收散射的超声波。优于传统的fUS，其对血流的敏感性是角度依赖性的，对垂直流动的敏感性较低，CRUST的交叉传输和全景检测场提供了对CBF的全向灵敏度。使用CRUST-PAT，CBF,氧饱和度,并测量感觉刺激过程中小鼠大脑的血红蛋白浓度变化，视场直径为约7毫米，空间分辨率约为170µm，和200赫兹的时间分辨率。结果表明CRUST-PAT是研究脑血流动力学的独特工具。
