Noninvasive label-free imaging of microhemodynamics by optical-resolution photoacoustic microscopy
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.
Additional Information© 2009 Optical Society of America. Received 26 Feb 2009; revised 26 Mar 2009; accepted 30 Mar 2009; published 24 Apr 2009. This work was sponsored by National Institutes of Health grants R01 EB000712, R01 NS46214 (Bioengineering Research Partnerships), R01 EB008085, and U54 CA136398 (Network for Translational Research). L.W. has a financial interest in Endra, Inc., which, however, did not support this work.
Published - oe-17-9-7688.pdf