Microvascular quantification based on contour-scanning photoacoustic microscopy
Accurate quantification of microvasculature remains of interest in fundamental pathophysiological studies and clinical trials. Current photoacoustic microscopy can noninvasively quantify properties of the microvasculature, including vessel density and diameter, with a high spatial resolution. However, the depth range of focus (i.e., focal zone) of optical-resolution photoacoustic microscopy (OR-PAM) is often insufficient to encompass the depth variations of features of interest—such as blood vessels—due to uneven tissue surfaces. Thus, time-consuming image acquisitions at multiple different focal planes are required to maintain the region of interest in the focal zone. We have developed continuous three-dimensional motorized contour-scanning OR-PAM, which enables real-time adjustment of the focal plane to track the vessels' profile. We have experimentally demonstrated that contour scanning improves the signal-to-noise ratio of conventional OR-PAM by as much as 41% and shortens the image acquisition time by 3.2 times. Moreover, contour-scanning OR-PAM more accurately quantifies vessel density and diameter, and has been applied to studying tumors with uneven surfaces.
Additional Information© 2014 SPIE. Paper 140366R received Jun. 9, 2014; revised manuscript received Aug. 21, 2014; accepted for publication Aug. 27, 2014; published online Sep. 15, 2014. The authors appreciate the close reading of the manuscript by Professor James Ballard. We also thank Wenxin Xing, Jinyang Liang, Yong Zhou, and Lidai Wang for helpful discussions. This work was sponsored by National Institutes of Health Grants DP1 EB016986 (NIH Director's Pioneer Award), R01 CA159959, R01 CA186567 (NIH Director's Transformative Research Award), and R01 EB016963. L.V.W. has financial interests in Microphotoacoustics Inc. and Endra Inc., neither of which supported this work. K.I.M. has a financial interest in Microphotoacoustics Inc.
Published - JBO_19_9_096011.pdf