Imaging H217O distribution in a phantom and measurement of metabolically produced H217O in live mice by proton NMR

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

“…Meiboom’s finding provided a mechanism for indirect detection of the H 2 17 O signal using 1 H MR imaging. This indirect 1 H-( 17 O) MR approach was anticipated to better inherent NMR sensitivity than that of the direct 17 O MR approach [41]. …”

“…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]. On the other hand, in the middle and late 1990s, Ronen et al and Reddy et al suggested that the 17 O-labeled H 2 17 O water could be detected by spin-echo proton imaging with 17 O decoupling [41–45] or proton T 1ρ dispersion imaging [46, 47], respectively, and these indirect 1 H-( 17 O) methods were used to image the H 2 17 O distribution in phantoms and animals.…”

The application of NMR in tumor angiogenesis research

“…Mapping the H 2 17 O concentration by this method requires measurement of the signal changes before and after H 2 17 O administration. Alternatively, Ronen and Navon [35] showed that the T 2 relaxation effect can be suppressed by 17 O decoupling, hence, concentration can be estimated by recording sequentially 17 O decoupled and non-decoupled images [36]. The J-coupling also augments at neutral pH the spin-lattice relaxation rate in the rotating frame, T 1q , of water protons enriched with 17 O [34], although the relaxivity (increase in relaxation per unit concentration of H 2 17 O) of T 1q is less than that of T 2 .…”

Quantitative 17O imaging towards oxygen consumption study in tumor bearing mice at 7 T

“…Non-invasive measurements of blood flow and oxygen consumption rate by in vivo 17 O nuclear magnetic resonance (NMR) have been reported [5][6][7][8][9][10][11]. The method of 17 O NMR detects solely metabolically generated H 2 17 O, since 17 O nuclear spin in O 2 molecule is NMR invisible, and possibly diamagnetic metabolites such as glyoxylic acid synthesized directly from 17 O 2 gas and glycine [12] should be under the detection level.…”

“…Due to low magnetogyric ratio (40.7 MHz at 7 T) and low natural abundance (0.037%), the sensitivity of 17 O NMR signal is extremely low compared to that of 1 H. Furthermore, the shortness of the transverse relaxation time of 17 O brings difficulty in the in vivo measurements especially by echo detection. In order to overcome these difficulties, proton-detected 17 O MRI such as 1 H-T 2 Magnetic Resonance Imaging 31 (2013) 643-650 weighted image [5], decoupling-1 H detection image [6,7], and 1 H-T 1ρ weighted image [8] have been proposed as the methods to attain high spatial and temporal resolution. The quantification of H 2 17 O by these methods, however, suffers from the wide distribution in the values of 1 H relaxation times.…”