International Journal on Magnetic Particle Imaging IJMPI
Vol. 11 No. 1 Suppl 1 (2025): Int J Mag Part Imag

Short Abstracts

A novel MPI blood assay for calculating ultra-short half-lives of magnetic tracers

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Marzieh Salimi (Johns Hopkins University School of Medicine), Shreyas Kuddannaya (Johns Hopkins University School of Medicine), Jeff Bulte (Johns Hopkins University School of Medicine)

Copyright (c) 2025 Marzieh Salimi, Shreyas Kuddannaya, Jeff Bulte

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Abstract

We present a magnetic particle imaging (MPI)-based blood assay that can be used to accurately calculate the blood half-life of magnetic nanoparticles (MNPs) without the need of labeling them. Dual-catheterized rats received 2.0 mg Fe of Synomag®-D70, Synomag®-D50, Resovist® and Feraheme® by femoral vein injection. The MPI signal of blood samples drawn from the femoral artery at various time points was then measured. Synomag®-D70 exhibited biexponential clearance with half-lives of 3.2 and 31.2 min, Synomag®-D50 a monoexponential clearance (t1/2=11.4 min), Resovist® a biexponential clearance (t1/2=2.4 and 10.8 min), and Feraheme® a biexponential clearance (t1/2=60.9 and 4.5 min). Our results showed that this MPI assay is a sensitive and specific method for calculating blood half-life of existing MNP formulations and those in the pipeline, with exquisite sensitivity for ultra-short half-lives.

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