Revealing a Third Dissolved-Phase Xenon-129 Resonance in Blood Caused by Hemoglobin Glycation.

Hyperpolarized (HP) xenon-129 ( 129 Xe), when dissolved in blood, has two NMR resonances: one in red blood cells (RBC) and one in plasma. The impact of numerous blood components on these resonances, however, has not yet been investigated. This study evaluates the effects of elevated glucose levels on the chemical shift (CS) and T2* relaxation times of HP 129 Xe dissolved in sterile citrated sheep blood for the first time. HP 129 Xe was mixed with sheep blood samples premixed with a stock glucose solution using a liquid-gas exchange module. Magnetic resonance spectroscopy was performed on a 3T clinical MRI scanner using a custom-built quadrature dual-tuned 129 Xe/ 1 H coil. We observed an additional resonance for the RBCs ( 129 Xe-RBC1) for the increased glucose levels. The CS of 129 Xe-RBC1 and 129 Xe-plasma peaks did not change with glucose levels, while the CS of 129 Xe-RBC2 (original RBC resonance) increased linearly at a rate of 0.015 ± 0.002 ppm/mM with glucose level. 129 Xe-RBC1 T2* values increased nonlinearly from 1.58 ± 0.24 ms to 2.67 ± 0.40 ms. As a result of the increased glucose levels in blood samples, the novel additional HP 129 Xe dissolved phase resonance was observed in blood and attributed to the 129 Xe bound to glycated hemoglobin (HbA 1c ).