Abstract #0928

Mason R, Kodibagkar V

The linear dependence of the spin lattice relaxation rate, R1, of the 19F NMR resonances of fluorocarbons on pO2 is well known and has been studied extensively. Recently, hexamethyldisiloxane (HMDSO) was presented as a potential analogous 1H NMR pO2 reporter molecule and bulk pO2 measurements were obtained by 1H spectroscopy. We have now extended application to present an imaging based method, PISTOL (Proton Imaging of Silanes to map Tissue Oxygenation Levels), and use HMDSO to map tissue oxygenation in rat thigh muscle in response to oxygen challenge. Dynamic changes in pO2 were assessed with respect to respiratory challenge. Given the lack of toxicity and ready availability of HMDSO, we believe it has great potential as a pO2 reporter molecule in the clinic.