Work

Effects of wavelength-dependent fluence attenuation on the noninvasive photoacoustic imaging of hemoglobin oxygen saturation in subcutaneous vasculature in vivo

Year: 2007

Type: article

Abstract: Quantitative measurements of the oxygen saturation of hemoglobin (sO 2 ) in a blood vessel in vivo presents a challenge in photoacoustic imaging. As a result of wavelength-dependent optical attenuation in the skin, the local fluence at a subcutaneous vessel varies with the optical wavelength in spectral measurement and hence needs to be compensated for so that the intrinsic absorption coefficient can be recovered. Here, by employing a simplified double-layer skin model, we demonstrate that although the absolute value of sO 2 in a vessel is seriously affected by the volume fraction of blood and the spatially averaged sO 2 in the dermis, the difference of sO 2 between neighboring vessels is minimally affected. Experimentally, we acquire compensational factors for the wavelength-dependent optical attenuation by measuring the PA spectrum of a subcutaneously inserted 25 µm thick black film using our PA microscope. We demonstrate in vivo that the difference in sO 2 between a typical artery and a typical vein is conserved before and after spectral compensation. This conservation holds regardless of the animal's systemic physiological state.

Source: Inverse Problems

DOI: 10.1088/0266-5611/23/6/s09

Authors: Konstantin Maslov, Hao F Zhang, Lihong V Wang

Institutions: Washington University in St. Louis, University of Wisconsin–Milwaukee

Language: English

Topic: Photoacoustic and Ultrasonic Imaging

Subfield: Biomedical Engineering

Field: Engineering

Domain: Physical Sciences

SDG: Good health and well-being

Open Access status: bronze

Funder: National Institutes of Health