In vitro and in vivo studies of 17O NMR sensitivity at 9.4 and 16.4 T

In vivo ¹⁷O magnetic resonance spectroscopy has been successfully applied for imaging the cerebral metabolic rate of oxygen consumption through the detection of metabolically produced H₂¹⁷O from the inhaled ¹⁷O‐labeled oxygen in animals at high field. In this study, we compared the ¹⁷O sensitivity for detecting natural abundance H₂¹⁷O signals from a phantom solution and rat brains at 9.4 and 16.4 T. The ¹⁷O signal‐to‐noise ratio measured at 16.4 T was 2.9‐ and 2.7–2.8‐fold higher than that at 9.4 T for the phantom and rat brain studies, respectively. Similarly, three‐dimensional ¹⁷O magnetic resonance spectroscopy imaging data showed a more than 2.7‐fold higher signal‐to‐noise ratio in the central rat brain region at 16.4 T than that at 9.4 T. The substantial ¹⁷O signal‐to‐noise ratio gain at ultrahigh field significantly improved the reliability for imaging the cerebral metabolic rate of oxygen consumption and will provide an opportunity for in vivo assessment of altered oxidative metabolism associated with brain functions and neurological diseases. Magn Reson Med, 2013. © 2012 Wiley Periodicals, Inc.