Nanophotonics Research Center, Institute of Microscale Optoelectronics, Shenzhen University, Shenzhen 518060, China.
School of Science and Information Science, Qingdao Agricultural University, Qingdao 266109, China.
ACS Sens. 2024 Apr 26;9(4):2166-2175. doi: 10.1021/acssensors.4c00292. Epub 2024 Apr 16.
Relying on the strong optical absorption of hemoglobin to pulsed laser energy, photoacoustic microscopy provides morphological and functional information on microvasculature label-freely. Here, we propose speckle variance photoacoustic microscopy (SV-PAM), which harnesses intrinsic imaging contrast from temporal-varied photoacoustic signals of moving red blood cells in blood vessels, for recovering three-dimension hemodynamic images down to capillary-level resolution within the microcirculatory tissue beds . Calculating the speckle variance of consecutive photoacoustic B-scan frames acquired at the same lateral position enables accurate identification of blood perfusion and occlusion, which provides interpretations of dynamic blood flow in the microvasculature, in addition to the microvascular anatomic structures. We demonstrate high-resolution hemodynamic imaging of vascular occlusion and reperfusion in the microvasculature of mice ears . The results suggest that our SV-PAM is potentially invaluable for biomedical hemodynamic investigations, for example, imaging ischemic stroke and hemorrhagic stroke.
利用血红蛋白对脉冲激光能量的强吸收，光声显微镜可对微脉管进行无标记的形态和功能成像。在这里，我们提出了斑点方差光声显微镜（SV-PAM），它利用血管中运动红细胞的时变光声信号的固有成像对比度，在微循环组织床内恢复到毛细血管水平分辨率的三维血流图像。计算在同一横向位置获得的连续光声 B 扫描帧的斑点方差，可以准确识别血液灌注和阻塞，这除了提供微血管解剖结构外，还可以解释微血管中的动态血流。我们在小鼠耳朵的微血管中演示了血管阻塞和再灌注的高分辨率血流成像。结果表明，我们的 SV-PAM 对于生物医学血流研究具有潜在的重要价值，例如，对缺血性中风和出血性中风进行成像。
