Characterization of Fe(III)-Deferoxamine and Mn(II)-Pectin as Magnetic Resonance Imaging Contrast Agents

Abstract

To find new contrast agents for magnetic resonance imaging (MRI), the spin-lattice relaxation time (T₁)-reducing activities of metal complexes of EDTA, N-hydroxyethyethylenediamine-N, N', N'-triacetic acid (HEDTA), diethylenetriamine-N, N, N', N", N‴-pentaacetic acid (DTPA), deferoxamine, mugineic acid, and pectin with Fe(III) or Mn(II) were investigated. Strong activity was found in Fe(III)-deferoxamine, Fe(III)-mugineic acid, or Mn(II)-pectin. In the actual MRI tomogram, Fe(III)-deferoxamine exhibited a contrast-enhancing effect comparable with that of Gd(III)-DTPA, and a much stronger effect was observed for Mn(II)-pectin. Fe(III)-deferoxamine and the Mn(II)-pectin appear to be candidates, respectively, as a new intravenous contrast agent and an oral gastrointestinal one.