- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Assessing Hemorrhagic Shock: Feasibility of Using an Ultracompact Photoacoustic Microscope
摘要： Hemorrhagic shock, as an important clinical issue, is regarding as a critical disease with a high mortality rate. Unfortunately, existing clinical technologies are inaccessible to assess the hemorrhagic shock via hemodynamics in microcirculation. Here, we propose an ultracompact photoacoustic microscope to assess hemorrhagic shock using a rat model and demonstrate its clinical feasibility by visualizing buccal microcirculation of healthy volunteers. Both functional and morphological features of the microvascular network including concentration of total hemoglobin (CHbT), number of blood vessels (VN), small vascular density (SVD) and vascular diameter (VD) were derived to assess the microvascular hemodynamics of different organs. Animal studies show the feasibility of the proposed tool to assess and stage the hemorrhagic shock via microcirculation. In vivo oral imaging of healthy volunteers indicates the translational possibility of this technique for clinical evaluation of hemorrhagic shock.
关键词： clinical evaluation,photoacoustic microscopy,hemodynamics,hemorrhagic shock,microcirculation
更新于2025-09-10 09:29:36
-
Comprehensive Characterization of Cerebrovascular Dysfunction in Blast Traumatic Brain Injury Using Photoacoustic Microscopy
摘要： Blast traumatic brain injury (bTBI) is a leading contributor to combat-related injuries and death. Although substantial emphasis has been placed on blast-induced neuronal and axonal injuries, co-existing dysfunctions in the cerebral vasculature, particularly the microvasculature, remain poorly understood. Here, we studied blast-induced cerebrovascular dysfunctions in a rat model of bTBI (blast overpressure: 187.8±18.3 kPa). Using photoacoustic microscopy, we quantified changes in cerebral hemodynamics and metabolism—including blood perfusion, oxygenation, flow, oxygen extraction fraction, and the metabolic rate of oxygen—4 hours post-injury. Moreover, we assessed the effect of blast exposure on cerebrovascular reactivity to vasodilatory stimulation. With vessel segmentation, we extracted these changes at the single-vessel level, revealing their dependence on vessel type (i.e., artery vs. vein) and diameter. We found that bTBI at this pressure level did not induce pronounced baseline changes in cerebrovascular diameter, blood perfusion, oxygenation, flow, oxygen extraction and metabolism, except for a slight sO2 increase in small veins (<45 μm) and blood flow increase in large veins (≥45 μm). In contrast, this blast exposure almost abolished cerebrovascular reactivity, including arterial dilation, flow upregulation, and venous sO2 increase. This study is the most comprehensive assessment of cerebrovascular structure and physiology in response to blast exposure to date. The observed impairment in cerebrovascular reactivity can potentially cause cognitive decline due to the mismatch between cognitive metabolic demands and vessel’s ability to dynamically respond to meet the demands. Also, the impaired cerebrovascular reactivity can lead to increased vulnerability of the brain to metabolic insults, including hypoxia and ischemia.
关键词： blast traumatic brain injury,cerebrovascular reactivity,photoacoustic microscopy,oxygen metabolism,hemodynamics
更新于2025-09-09 09:28:46
-
Passive ultrasound aided acoustic resolution photoacoustic microscopy imaging for layered heterogeneous media
摘要： Photoacoustic imaging reconstructions usually assume a known speed-of-sound (SOS) distribution; however, in most cases, the SOS distribution is not revealed and is dif?cult to estimate from photoacoustic signals. In this paper, we propose passive ultrasound aided acoustic resolution photoacoustic microscopy which simultaneously reconstructs SOS distributions and photoacoustic images for layered heterogeneous media. The passive ultrasound is a kind of laser-induced acoustic wave generated by a transducer absorbing the backscattered light. It can be used to measure the layer thicknesses due to its sensitivity to structural information and broad bandwidth and further determine the SOS distributions. After estimating the SOS distributions, a phase shift plus interpo- lation is employed to reconstruct the photoacoustic image for heterogeneous media. Without intro- ducing additional hardware, this method can be conveniently incorporated into a conventional photoacoustic imaging system. A curved shell immersed in water is adopted as a layered heteroge- neous phantom, and the proposed method reconstructs the targets (carbon rods) under this shell. Under the test of a 5 MHz focused transducer (NA 0.25), the maximum reconstruction deviation of 1.2 mm carbon rods is only 0.15 mm.
关键词： passive ultrasound,speed-of-sound distribution,acoustic resolution photoacoustic microscopy,layered heterogeneous media,photoacoustic imaging
更新于2025-09-04 15:30:14