Monitoring Whole-Body Inflammation with Gallium-68-Labeled Polydopamine Iron Oxide Particles via Hybrid Immuno-PET-MRI.

Monitoring immune reactions via inflammation imaging provides valuable disease prognosis but remains limited by the currently available probes and imaging capabilities. In this study, a bimodal imaging probe was developed from microsized polydopamine matrix-based magnetic particles (M3P) functionalized with antibodies targeting vascular cell adhesion molecule-1 (VCAM-1) and radiolabeled with the radioisotope gallium-68. This probe combines sensitive inflammation detection via positron emission tomography (immuno-PET) and high-resolution mapping via magnetic resonance imaging (immuno-MRI). It represents a powerful disease diagnosis tool to assess the status of systemic inflammation in sepsis, as whole-body immuno-PET enables rapid evaluation of the situation, and immuno-MRI provides a more detailed characterization of the identified affected tissues. The elimination profile of the M3P probe is restricted to the mononuclear phagocyte system and does not undergo renal clearance, which is suitable for applications in kidney disorders. The efficacy of the hybrid immuno-PET-MRI diagnosis protocol was tested in a murine model of rhabdomyolysis. Kidney inflammation was detected by whole-body immuno-PET, and vascular inflammation patterns could be revealed by high-resolution immuno-MRI. This bimodal PET-MRI probe could significantly improve the inflammation monitoring in pathologies characterized by systemic inflammation or lung and kidney dysfunction.