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/T2 ) 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 22°C (pH 7.3) were 0.021, 0.060, and 0.077 s(-1) mM(-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(-1) mM(-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 T2 contrast agent for MRI at concentrations that are already approved for human use.