The use of sulfur hexafluoride microbubbles for contrast-enhanced ocular ultrasonography of the pecten oculi in birds.

Abstract

The pecten oculi is a vascular and pigmented structure localized within the posterior segment of all avian eyes. Its primary function is not fully understood yet. As ultrasonography (US) is a useful imaging modality for evaluation of the pecten oculi, the objective of this study was to investigate the utility of an intravenous contrast solution of sulfur hexafluoride (SF6) microbubbles as a means of enhancing visualization of the pecten oculi in normal birds. Ten adult individuals of the following avian species were evaluated: 1 roadside hawk (Rupornis magnirostris), 1 stygian owl (Asio stygius), 2 striped owls (Asio clamator), 2 burrowing owls (Athene cunicularia), 2 ring-necked parakeet (Psittacula krameri), and 2 domestic chickens (Gallus gallus domesticus). After baseline ocular sonograms were obtained in sedated animals, 4.5μg/kg of a contrast solution containing SF6 microbubbles was administered intravenously and US of the right eye was immediately performed. US was continued during injection to provide real-time imaging of the pecten oculi during vascular perfusion of contrast material. Within 2-3seconds following intravenous contrast administration, microbubbles reached the pecten oculi of all birds investigated and provided significant ultrasonographic contrast enhancement. SF6 microbubble contrast ultrasonography in birds is a safe and easy procedure that provides increased contrast and enhanced visualization of the pecten oculi. Future use may enable further discovery of its physiologic functions and aid in the development of therapeutic plans for avian intraocular disease.