Characterization of D‐maltose as a T 2 ‐exchange contrast agent for dynamic contrast‐enhanced MRI

Purpose We sought to investigate the potential of D‐maltose, D‐sorbitol, and D‐mannitol as T 2 exchange magnetic resonance imaging (MRI) contrast agents. We also sought to compare the in vivo pharmacokinetics of D‐maltose with D‐glucose with dynamic contrast enhancement (DCE) MRI. Methods T 1 and T 2 relaxation time constants of the saccharides were measured using eight pH values and nine concentrations. The effect of echo spacing in a multiecho acquisition sequence used for the T 2 measurement was evaluated for all samples. Finally, performances of D‐maltose and D‐glucose during T 2 ‐weighted DCE‐MRI were compared in vivo. Results Estimated T 2 relaxivities (r 2 ) of D‐glucose and D‐maltose were highly and nonlinearly dependent on pH and echo spacing, reaching their maximum at pH = 7.0 (∼0.08 mM −1 s −1 ). The r 2 values of D‐sorbitol and D‐mannitol were estimated to be ∼0.02 mM −1 s −1 and were invariant to pH and echo spacing for pH ≤7.0. The change in T 2 in tumor and muscle tissues remained constant after administration of D‐maltose, whereas the change in T 2 decreased in tumor and muscle after administration of D‐glucose. Therefore, D‐maltose has a longer time window for T 2 ‐weighted DCE‐MRI in tumors. Conclusion We have demonstrated that D‐maltose can be used as a T 2 exchange MRI contrast agent. The larger, sustained T 2 ‐weighted contrast from D‐maltose relative to D‐glucose has practical advantages for tumor diagnoses during T 2 ‐weighted DCE‐MRI. Magn Reson Med 80:1158–1164, 2018. © 2018 International Society for Magnetic Resonance in Medicine.