title: In vivo depth-resolved oxygen saturation by Dual-Wavelength Photothermal (DWP) OCT.
abstract: Microvasculature hemoglobin oxygen saturation (SaO2) is important in the progression of various pathologies. Non-invasive depth-resolved measurement of SaO2 levels in tissue microvasculature has the potential to provide early biomarkers and a better understanding of the pathophysiological processes allowing improved diagnostics and prediction of disease progression. We report proof-of-concept in vivo depth-resolved measurement of SaO(2) levels in selected 30 µm diameter arterioles in the murine brain using Dual-Wavelength Photothermal (DWP) Optical Coherence Tomography (OCT) with 800 nm and 770 nm photothermal excitation wavelengths. Depth location of back-reflected light from a target arteriole was confirmed using Doppler and speckle contrast OCT images. SaO(2) measured in a murine arteriole with DWP-OCT is linearly correlated (R(2)=0.98) with systemic SaO(2) values recorded by a pulse-oximeter. DWP-OCT are steadily lower (10.1%) than systemic SaO(2) values except during pure oxygen breathing. DWP-OCT is insensitive to OCT intensity variations and is a candidate approach for in vivo depth-resolved quantitative imaging of microvascular SaO(2) levels.
authors: Department of Ophthalmology, The University of Texas Health Science Center, San Antonio, Texas 78229, USA. rkuranov@yahoo.com
authors: Roman V
authors: RV
authors: Kuranov
authors: Shams
authors: S
authors: Kazmi
authors: Austin B
authors: AB
authors: McElroy
authors: Jeffrey W
authors: JW
authors: Kiel
authors: Andrew K
authors: AK
authors: Dunn
authors: Thomas E
authors: TE
authors: Milner
authors: Timothy Q
authors: TQ
authors: Duong
mesh_terms: D000818:Animals; D001160:Arterioles / Q000378:metabolism*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005336:Fiber Optic Technology / Q000295:instrumentation*; D008297:Male; D051379:Mice; D010092:Oximetry / Q000295:instrumentation*; D010100:Oxygen / Q000097:blood*; D012031:Refractometry / Q000295:instrumentation*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D041623:Tomography, Optical Coherence / Q000295:instrumentation*
chemical_list: D010100:Oxygen