Open Access Conference Proceedings

Magnetic resonance imaging (MRI) is a powerful tool for studying nanoparticle biodistribution in vivo. However, conventional approaches usually rely on qualitative assessment from T1-, T2-, or T2*-weighted images. These methods provide only indirect estimates of nanoparticle concentration and are sensitive to motion artifacts. We present a new quantitative MRI methodology for evaluating biodistribution of Gadolinium-labeled nanoparticles in small animals. The method is based on T1 mapping and designed to be robust against respiratory and potentially also cardiac motion, ensuring reliable longitudinal measurements of nanoparticle concentrations.The approach was tested in six tumor-bearing mice (Balb/c, 4T1 tumor), each imaged at five fixed time points within 48 hours after intravenous administration of Gadolinium-labeled lipid nanoparticles carrying ellipticine, or, as a reference, the standard contrast agent Gadovist. Our results demonstrate reproducible T1 quantification in the tumor, kidney, liver, and spleen, enabling direct and quantitative analysis of nanoparticle accumulation and clearance over time.This methodology represents a robust, noninvasive strategy for assessing nanoparticle biodistribution and may facilitate the development of novel nanomedicine therapies.

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