Simultaneous imaging of oxygen tension and blood flow in animals using a digital micromirror device


In this study we present a novel imaging method that combines high resolution cerebral blood flow imaging with a highly flexible map of absolute $p_{\ce{O2}}$. In vivo measurements of $p_{\ce{O2}}$ in animals using phosphorescence quenching is a well established method, and is preferable over electrical probes which are inherently invasive and are limited to single point measurements. However, spatially resolved $p_{\ce{O2}}$ measurements using phosphorescence lifetime quenching typically require expensive cameras to obtain images of $p_{\ce{O2}}$ and often suffer from poor signal to noise. Our approach enables us to retain the high temporal resolution and sensitivity of single point detection of phosphorescence by using a digital micromirror device (DMD) to selectively illuminate arbitrarily shaped regions of tissue. In addition, by simultaneously using Laser Speckle Contrast Imaging (LSCI) to measure relative blood flow, we can better examine the relationship between blood flow and absolute $p_{\ce{O2}}$. We successfully used this instrument to study changes that occur during ischemic conditions in the brain with enough spatial resolution to clearly distinguish different regions. This novel instrument will provide researchers with an inexpensive and improved technique to examine multiple hemodynamic parameters simultaneously in the brain as well as other tissues.

Journal article
Optics Express