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Magnetic-susceptibility-dependent ratiometric probes for enhancing quantitative MRI
Cheng Zhang1, Bin Nan1, Juntao Xu1
1State Key Laboratory for Chemo/Bio-Sensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha, China.
Nature Biomedical Engineering
|November 29, 2024
Summary
New ratiometric magnetic resonance imaging (MRI) probes enable accurate analyte quantification by decoupling probe activation from probe accumulation. These advanced probes offer enhanced sensitivity for real-time molecular imaging in vivo.
Area of Science:
- Biomedical Imaging
- Nanotechnology
- Medical Diagnostics
Background:
- Quantitative measurements in magnetic resonance imaging (MRI) are often limited by the inability to differentiate probe activation signals from probe accumulation.
- Existing MRI techniques struggle with distinguishing analyte-induced probe activation from the concentration of the intact probe, hindering accurate quantification.
Purpose of the Study:
- To develop and validate novel ratiometric MRI probes for enhanced sensitivity and quantitative accuracy in analyte detection.
- To overcome the limitations of distinguishing analyte-specific signals from probe concentration variations in MRI.
Main Methods:
- Development of polymeric probes incorporating paramagnetic Mn-porphyrin and superparamagnetic iron oxide nanoparticles.
- Utilizing magnetic-susceptibility-dependent magnetic resonance tuning to achieve a high relaxivity-ratio change (>2.5-fold at 7 T).
- In vivo testing in mice for real-time dynamic imaging of hydrogen peroxide (H2O2), hydrogen sulfide (H2S), and pH in various pathological models.
Main Results:
- The ratiometric probes demonstrated a high relaxivity-ratio change, enabling analyte concentration to be measured independently of probe concentration.
- Quantitative real-time dynamic imaging of H2O2, H2S, and pH was successfully achieved in mice with subcutaneous tumors, drug-induced liver injury, and orthotropic gliomas.
- The probes provided both molecular insights and anatomical information, overcoming interference from dynamic probe concentration changes.
Conclusions:
- Ratiometric MRI probes offer a significant advancement for sensitive and quantitative molecular imaging.
- These probes can provide valuable molecular insights into pathological processes by accurately measuring analyte concentrations in real-time.
- The developed probes circumvent interference from probe accumulation, improving the reliability of MRI-based diagnostics.
