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Abstract #22708 Published in IGR 11-1
Three-dimensional mapping of chorioretinal vascular oxygen tension in the rat
Shahidi M; Wanek J; Blair NP; Mori MInvestigative Ophthalmology and Visual Science 2009; 50: 820-825
PURPOSE: An optical section phosphorescence lifetime imaging system was developed for three-dimensional mapping of oxygen tension (PO2) in chorioretinal vasculatures. METHODS: A laser line was projected at an oblique angle and scanned on the retina after intravenous injection of an oxygen-sensitive molecular probe to generate phosphorescence optical section images. An automated software algorithm segmented and combined images from spatially adjacent locations to construct depth-displaced en face retinal images. Intravascular PO2 was measured by determining the phosphorescence lifetime. Three-dimensional chorioretinal PO2 maps were generated in rat eyes under varying fractions of inspired oxygen. RESULTS: Under an air-breathing condition, mean PO2 in the choroid, retinal arteries, capillaries, and veins were 58±2 mmHg, 47±2 mmHg, 44±2 mmHg, and 35±2 mmHg, respectively. The mean arteriovenous PO2 difference was 12±2 mmHg. With a lower fraction of inspired oxygen, chorioretinal vascular PO2 and mean arteriovenous PO2 differences decreased compared with measurements under an air-breathing condition. Retinal venous PO2 was statistically lower than PO2 measured in the retinal artery, capillaries, and choroid (P<0.004). CONCLUSIONS: Three-dimensional mapping of chorioretinal oxygen tension allowed quantitative PO2 measurements in large retinal blood vessels and in retinal capillaries. This method has the potential to facilitate better understanding of retinal oxygenation in health and disease.
Dr. M. Shahidi, Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, Illinois 60612, USA. mahnshah@uic.edu
Classification:
6.11 Bloodflow measurements (Part of: 6 Clinical examination methods)
5.1 Rodent (Part of: 5 Experimental glaucoma; animal models)
