High-resolution T₁ MRI via renally clearable dextran nanoparticles with an iron oxide shell

Area of Science:

• Biomedical Engineering
• Nanotechnology
• Medical Imaging

Background:

• Magnetic resonance imaging (MRI) contrast agents enhance anatomical visualization.
• Whole-body MRI faces challenges in resolving fine structures due to poor image resolution.

Purpose of the Study:

• To develop a nanoparticle contrast agent with improved T1 MRI contrast for high-resolution imaging.
• To evaluate the nanoparticle's synthesis, biocompatibility, and imaging performance compared to existing agents.

Main Methods:

• Synthesized a nanoparticle with a polysaccharide core and hydrous ferric oxide shell in aqueous solution at room temperature.
• Evaluated the nanoparticle's relaxivity coefficient, blood circulation, renal clearance, and opsonization prevention.
• Compared the imaging performance of the nanoparticle against Dotarem (gadoterate meglumine) in rodent and rabbit models.

Main Results:

• The nanoparticle generated strong T1 MRI contrast with a relaxivity coefficient ratio of ~1.2.
• Facilitated imaging of microvessels (cerebral, coronary, peripheral) in rodents and lower-extremity vessels in rabbits at resolutions of a few hundred micrometres.
• Demonstrated favorable blood circulation and renal clearance profiles, preventing opsonization.
• Exhibited superior imaging performance compared to the clinically approved gadolinium-based agent, Dotarem.

Conclusions:

• The novel nanoparticle exhibits excellent biocompatibility and imaging performance for MRI.
• Its properties make it advantageous for preclinical and clinical applications requiring high-resolution microvessel imaging.
• This agent offers a promising alternative to current MRI contrast agents, particularly for whole-body imaging challenges.