Rigid Mn(II) chelate as efficient MRI contrast agent for vascular imaging

Area of Science:

• * Inorganic Chemistry
• * Medicinal Chemistry
• * Medical Imaging

Background:

• * Development of novel contrast agents for Magnetic Resonance Imaging (MRI) is crucial for enhanced diagnostic capabilities.
• * Existing manganese-based contrast agents face challenges in relaxivity and stability.
• * Aza-semi-crown ligands offer a promising scaffold for designing new MRI contrast agents.

Purpose of the Study:

• * To design and synthesize a novel rigidified aza-semi-crown pentadentate ligand.
• * To investigate the complexation of the ligand with Manganese(II) ions in an aqueous environment.
• * To evaluate the performance of the resulting manganese complex as an MRI contrast agent, focusing on longitudinal relaxivity and signal enhancement.

Main Methods:

• * Synthesis of a pentadentate ligand incorporating pyridine and piperidine rings for structural rigidity.
• * Complexation reaction between the synthesized ligand and Mn(II) ions in water.
• * Characterization of the Mn(II) complex.
• * Measurement of longitudinal relaxivity (r1) of the complex.
• * In vitro evaluation of signal intensity enhancement in vascular mimic phantoms using a clinical MRI scanner.

Main Results:

• * Successful design and synthesis of the rigidified aza-semi-crown pentadentate ligand.
• * Formation of a stable Mn(II) complex in water.
• * The Mn(II) complex exhibited significantly improved longitudinal relaxivity compared to existing agents.
• * Efficient enhancement of signal intensity for vascular imaging was observed under clinical MRI conditions.

Conclusions:

• * The novel rigidified aza-semi-crown pentadentate ligand effectively complexes with Mn(II) in water.
• * The resulting manganese complex demonstrates superior longitudinal relaxivity, making it a promising candidate for MRI contrast agents.
• * This development offers potential for improved vascular imaging in clinical magnetic resonance imaging applications.