Advancing Magnetic Particle Imaging: Innovative A Nanoparticle Design and Signal Processing for Improved Resolution and Sensitivity

Background:Magnetic resonance imaging (MRI) frequently relies on gadolinium-based contrast agents (GBCAs) to enhance diagnostic accuracy; however, concerns regarding nephrogenic systemic fibrosis and gadolinium deposition have prompted the search for safer alternatives, particularly for patients with renal impairment. Magnetic Particle Imaging (MPI) is an emerging, radiation-free imaging modality that directly visualises superparamagnetic iron oxide nanoparticles (SPIONs) and offers high sensitivity and quantitative capability.

Aim:This narrative review aims to critically evaluate the principles, tracer chemistry, imaging performance, safety profile, and clinical applications of MPI using SPIONs, with emphasis on its potential as a safer alternative to GBCA-enhanced imaging.

Methods:A structured literature search was conducted across PubMed, Scopus, Web of Science, and Google Scholar following PRISMA guidance. Peer-reviewed experimental, translational, and clinical studies related to MPI, SPION tracers, and contrast agent safety were included. Data were synthesized descriptively, with comparative trend and statistical analyses applied where feasible.

Results:A total of 41 studies met the inclusion criteria. MPI demonstrated high tracer sensitivity with linear signal quantification (R² > 0.95) and superior temporal resolution compared with MRI and PET. Reported spatial resolution ranged from 0.8 to 1.2 mm. No studies reported nephrotoxicity or fibrosis associated with SPIONs. Application-based evidence supported MPI’s effectiveness in cell tracking, vascular and perfusion imaging, and emerging oncological diagnostics. Comparative analyses indicated statistically significant advantages of MPI in temporal resolution and tracer quantification (p < 0.01).

Conclusion:MPI using SPIONs is a promising, safe, and quantitative imaging modality with substantial translational potential. Although current evidence is largely preclinical, ongoing technological and clinical advancements may enable MPI to complement existing imaging techniques, particularly in radiation-free and renal-safe diagnostic applications.