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Measurement of Tumor T2* Relaxation Times after Iron Oxide Nanoparticle Administration
Published on: May 19, 2023
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Imaging Tumor Necrosis with Ferumoxytol.
Maryam Aghighi1, Daniel Golovko2, Celina Ansari1
1Department of Radiology, Molecular Imaging Program at Stanford, Stanford University, Stanford, CA, United States of America.
Plos One
|November 17, 2015
Summary
Ultra-small superparamagnetic iron oxide nanoparticles (USPIO) show distinct MRI signal changes based on their location within tumors. This allows for non-invasive characterization of the tumor microenvironment composition.
Area of Science:
- Biomedical Imaging
- Nanotechnology
- Oncology
Background:
- Ultra-small superparamagnetic iron oxide nanoparticles (USPIO) are promising MRI contrast agents.
- USPIO's relaxation rate enhancement depends on intracellular or extracellular compartmentalization within the tumor microenvironment.
Purpose of the Study:
- To compare the T1- and T2-enhancement patterns of intracellular and extracellular USPIO.
- To enable non-invasive characterization of tumor microenvironment composition using USPIO-enhanced MRI.
Main Methods:
- Ferumoxytol-enhanced MRI was performed on mouse models (4T1 and MMTV-PyMT mammary tumors) and pilot patient data (sarcomas).
- R1 relaxation rates and transendothelial leakage rates were calculated and compared with histopathology.
- T1- and T2-enhancement patterns were analyzed descriptively in patients.
Main Results:
- 4T1 tumors showed extracellular USPIO in necrotic cores (high T1, low T2 signal).
- MMTV-PyMT tumors showed intracellular USPIO in macrophages (low T2 signal).
- 4T1 tumors exhibited significantly higher R1 rates and transendothelial leakage compared to MMTV-PyMT tumors.
Conclusions:
- Differential T1- and T2-enhancement patterns of USPIO in tumors correlate with their intracellular and extracellular locations.
- This imaging approach can characterize the composition of the tumor microenvironment non-invasively.
