Characterization of D-maltose as a T2-exchange contrast agent for dynamic contrast-enhanced MRI

PurposeWe 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. MethodsT(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. ResultsEstimated 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 (approximate to 0.08mM(-1) s(-1)). The r(2) values of D-sorbitol and D-mannitol were estimated to be approximate to 0.02mM(-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. ConclusionWe 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. (c) 2018 International Society for Magnetic Resonance in Medicine.