Measurement of water movement in the rabbit eye in vivo using H₂¹⁷O

Abstract

Topically applied (eyedrop) H2(17)O (10% enrichment) was used in magnetic resonance studies to quantify intraocular water dispersion in vivo. The rate of H2(17)O removed from the aqueous chamber is in the order of 0.1 ml/min/ml of tissue. Similar results are obtained with either proton imaging or 17O spectroscopy. Parallel experiments of direct injection of H2(17)O into the aqueous chamber supported the topical data. Proton MR imaging of H2(17)O dissipation from the aqueous chamber with clinical imagers, coupled with eyedrop application, suggests clinical possibilities.

Deuterium MRin VivoImaging of the Rat Eye Using 2H2O

“…By NMR, the corresponding values for the rabbit were 0.090 to 0.110/min (1,7). The flow of aqueous humor in rats was apparently faster than in rabbits and humans, as the flow rate constant in the present study (O.4/min) was larger.…”

In vivo oxygen-17 NMR for imaging brain oxygen metabolism at high field

“…In the late 1980s and early 1990s, 17 O-enriched H 2 17 O water was used as a potential T 2 (transverse relaxation time) contrast agent for the proton MRI by Hopkins’ group and others for studying tissue perfusion in various animal models [29–33]. Meanwhile, Mateescu et al demonstrated the in vivo 17 O MRS detection of nascent mitochondrial water in larva and mouse breathing air with 17 O-enriched oxygen gas [34, 35]; Aria et al explored the feasibility of in vivo 17 O NMR for estimation of cerebral blood flow (CBF) and oxygen consumption in animal models of rat, rabbit and dog [6, 7, 36]; Pekar et al reported that coarse CMRO 2 images (0.8cc nominal resolution) can be obtained in the cat brain using 17 O NMR imaging and 17 O-enriched oxygen gas [5, 37]; and Fiat et al examined possible methods for determination of CMRO 2 and CBF in animal brain (and potentially in human brain) using in vivo 17 O MRS/MRI [38–40].…”

Estimation of the regional cerebral metabolic rate of oxygen consumption with proton detected 17O MRI during precision 17O2 inhalation in swine

“…The direct techniques for H 2 17 O detection utilize MR spectroscopy or imaging at the Larmor frequency of 17 O. In vivo studies using the direct techniques have shown the possibility of detecting 17 O in vivo (Mateescu et al, 1987) and have measured metabolism (Arai et al, 1990; Fiat et al, 1992), flow (Arai et al, 1998; Kwong et al, 1991), or both (Arai et al, 1991; Pekar et al, 1991). Two groups have been able to demonstrate decreased 17 O metabolism in the setting of hypothermia, one in insects (Mateescu and Cabrera, 1997) and more recently using 3D spectroscopy on rats at 9.4T (Zhu et al, 2007).…”