title: Noninvasive photoacoustic angiography of animal brains in vivo with near-infrared light and an optical contrast agent.
abstract: Optical contrast agents have been widely applied to enhance the sensitivity and specificity of optical imaging with near-infrared (NIR) light. However, because of the overwhelming scattering of light in biological tissues, the spatial resolution of traditional optical imaging degrades drastically as the imaging depth increases. Here, for the first time to our knowledge, we present noninvasive photoacoustic angiography of animal brains in vivo with NIR light and an optical contrast agent. When indocyanine green polyethylene glycol, a novel absorption dye with prolonged clearance, is injected into the circulatory system of a rat, it obviously enhances the absorption contrast between the blood vessels and the background tissues. Because NIR light can penetrate deep into the brain tissues through the skin and skull, we are able to successfully reconstruct the vascular distribution in the rat brain from the photoacoustic signals. On the basis of differential optical absorption with and without contrast enhancement, a photoacoustic angiograph of a rat brain is acquired that matches the anatomical photograph well and exhibits high spatial resolution and a much-reduced background. This new technology demonstrates the potential for dynamic and molecular biomedical imaging.
authors.affiliation: Optical Imaging Laboratory, Department of Biomedical Engineering, Texas A&M University, College Station, Texas 77843-3120, USA.
authors.forename: Xueding
authors.initials: X
authors.lastname: Wang
authors.forename: Geng
authors.initials: G
authors.lastname: Ku
authors.forename: Malgorzata A
authors.initials: MA
authors.lastname: Wegiel
authors.forename: Darryl J
authors.initials: DJ
authors.lastname: Bornhop
authors.forename: George
authors.initials: G
authors.lastname: Stoica
authors.forename: Lihong V
authors.initials: LV
authors.lastname: Wang
mesh_terms: D000818:Animals; D002533:Cerebral Angiography / Q000295:instrumentation; D003287:Contrast Media; D004867:Equipment Design; D007208:Indocyanine Green / Q000031:analogs & derivatives; D011092:Polyethylene Glycols; D051381:Rats; D019265:Spectroscopy, Near-Infrared / Q000295:instrumentation; D014465:Ultrasonics
chemical_list: D003287:Contrast Media; D011092:Polyethylene Glycols; D007208:Indocyanine Green