RPI ID: 2014-052-401
Innovation Summary: NXMRI combines X‑ray excitation of nanoparticles with MRI readout to localize contrast agents by monitoring changes in resonance parameters (T1/T2/T2*) induced by excitation. Nanoparticles (e.g., nanophosphors) embedded in tissue are energized by X‑rays or UV, altering their local magnetic environment. An MRI acquisition before and after excitation measures the parameter shift, yielding high-specificity localization without heavy reliance on optical paths. Because MRI penetrates deeply with high spatial resolution, the approach overcomes the depth limits of fluorescence imaging. Compared to PET/SPECT, it avoids ionizing tracer injections beyond the excitation step and can provide dynamic, long-lived contrast. The method is modality-agnostic regarding nanoparticle composition, enabling tailored agents for brain, cardiac, or oncologic imaging. Systems comprise an excitation source, MRI scanner, and processor to compute differential maps from pre/post scans. This hybrid strategy adds molecular sensitivity to MR structural imaging workflows.
Challenges / Opportunities: Designing nanoparticles that produce robust, safe, and repeatable MR parameter shifts is non-trivial. Co-registration of X‑ray excitation fields with MR volumes requires precise synchronization and safety interlocks. Dose management for repeated excitations must meet clinical limits while providing adequate signal change. Heterogeneity in nanoparticle distribution can complicate quantitation and standardization. Translational pathways demand biocompatibility, clearance, and toxicology data for regulatory approval. Sequence optimization (timing/TE/TR) is needed to maximize sensitivity to T1/T2/T2* changes. Motion between pre/post scans introduces artifacts; prospective motion correction helps. Integration with existing MR hardware and room layouts may require custom fixtures and workflow changes.
Key Benefits: ✓ Deep-tissue molecular localization with MR resolution ✓ Overcomes optical depth limitations of fluorescence ✓ Differential pre/post readout improves specificity ✓ Flexible across nanoparticle chemistries ✓ Potentially lower tracer burden than nuclear methods ✓ Compatible with standard MRI platforms (with add-on source) ✓ Enables dynamic/long-lived contrast paradigms ✓ Augments conventional anatomical MR
Applications: • Oncology—tumor targeting and therapy monitoring • Neuroimaging—brain localization beyond optical reach • Cardiac imaging—ischemia and perfusion mapping adjunct • Regenerative medicine—tracking labeled constructs • Drug delivery—localization of nanoparticle carriers • Preclinical molecular imaging studies
Keywords: NXMRI; nanoparticles; X-ray excitation; MRI contrast; T1/T2/T2*; nanophosphors; molecular imaging
Intellectual Property: Issued US patent no. 12,151,002