Natural D-glucose as a biodegradable MRI relaxation agent

Purpose Demonstrate applicability of natural D-glucose as a T₂ MRI contrast agent. Methods D-glucose solutions were prepared at multiple concentrations and variable pH. The relaxation rate (R₂ = 1/T ₂) was measured at 3, 7, and 11.7 T. Additional experiments were performed on blood at 11.7 T. Also, a mouse was infused with D-glucose (3.0 mmol/kg) and dynamic T₂ weighted images of the abdomen acquired. Results The transverse relaxation rate depended strongly on glucose concentration and solution pH. A maximum change in R₂ was observed around physiological pH (pH 6.8-7.8). The transverse relaxivities at 22C (pH 7.3) were 0.021, 0.060, and 0.077 s^-1mM^-1 at 3.0, 7.0, and 11.7 T, respectively. These values showed good agreement with expected values from the Swift-Connick equation. There was no significant dependence on glucose concentration or pH for T₁ and the diffusion coefficient for these solutions. The transverse relaxivity in blood at 11.7 T was 0.09 s ^-1mM^-1. The dynamic in vivo experiment showed a 10% drop in signal intensity after glucose infusion followed by recovery of the signal intensity after about 50-100 s. Conclusion Glucose can be used as a T ₂ contrast agent for MRI at concentrations that are already approved for human use. Magn Reson Med 72:823-828, 2014.