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Updated: Jun 23, 2026
Three-dimensional Optical-resolution Photoacoustic Microscopy
Published on: May 3, 2011
Noninvasive label-free imaging of microhemodynamics by optical-resolution photoacoustic microscopy
Song Hu1, Konstantin Maslov, Lihong V Wang
1Department of Biomedical Engineering, Washington University, St. Louis, MO 63130, USA.
Abstract:
In vivo microcirculatory imaging facilitates the fundamental understanding of many major diseases. However, existing techniques generally require invasive procedures or exogenous contrast agents, which perturb the intrinsic physiology of the microcirculation. Here, we report on optical-resolution photoacoustic microscopy (OR-PAM) for noninvasive label-free microcirculatory imaging at cellular levels. For the first time, OR-PAM demonstrates quantification of hemoglobin concentration and oxygenation in single microvessels down to capillaries. Using this technique, we imaged several important yet elusive microhemodynamic activities-including vasomotion and vasodilation-in small animals in vivo. OR-PAM enables functional volumetric imaging of the intact microcirculation, thereby providing greatly improved accuracy and versatility for broad biological and clinical applications.
Insights
Optical-resolution photoacoustic microscopy (OR-PAM) offers noninvasive, label-free imaging of the microcirculation. This technique quantifies hemoglobin and oxygenation in single capillaries, revealing microhemodynamic activities in vivo.
Area of Science:
- Biomedical Optics
- Medical Imaging
- Physiology
Background:
- Microcirculatory imaging is crucial for understanding diseases.
- Current methods are often invasive or use contrast agents, altering physiology.
- A noninvasive, label-free technique is needed for accurate microcirculation studies.
Purpose of the Study:
- To introduce optical-resolution photoacoustic microscopy (OR-PAM) for noninvasive, label-free microcirculatory imaging.
- To demonstrate OR-PAM's capability for quantifying hemoglobin concentration and oxygenation in single microvessels.
- To visualize microhemodynamic activities like vasomotion and vasodilation in vivo.
Main Methods:
- Development and application of optical-resolution photoacoustic microscopy (OR-PAM).
- Label-free imaging of microcirculation at cellular resolution.
- In vivo imaging in small animals.
Main Results:
- OR-PAM successfully performed noninvasive, label-free microcirculatory imaging.
- Quantification of hemoglobin concentration and oxygenation in single capillaries was achieved.
- Microhemodynamic activities, including vasomotion and vasodilation, were imaged in vivo.
Conclusions:
- OR-PAM provides a novel, noninvasive method for studying the microcirculation.
- The technique enables accurate quantification of blood parameters and visualization of hemodynamics.
- OR-PAM offers enhanced accuracy and versatility for biological and clinical applications.
