1H-nuclear magnetic resonance deoxymyoglobin signal as indicator of intracellular oxygenation in myocardium.

We report in this study that the intracellular oxygenation state is measurable with the 1H nuclear magnetic resonance signal of the proximal histidine N delta H proton of deoxymyoglobin. The signal appears in a clear spectral region of the 1H spectrum and is sensitive to various hypoxic and ischemic conditions. In perfused heart, the deoxymyoglobin's response to tissue oxygenation precedes the one reflected in the 31P phosphocreatine or ATP signals, suggesting that oxidative energy metabolism is still sufficient even when the myoglobin is partially saturated with oxygen. Our method offers then a unique way to observe tissue oxygenation and its interaction in localized tissue region in vivo.