Quantification of superparamagnetic iron oxide (SPIO)-labeled cells using MRI
Ali M Rad1, Ali S Arbab, A S M Iskander
1Department of Radiology, Henry Ford Health System, Detroit, Michigan 48202, USA.
Journal of Magnetic Resonance Imaging : JMRI
|July 12, 2007
Summary
Magnetic resonance imaging (MRI) can quantify superparamagnetic iron oxide (SPIO)-labeled cells. Careful consideration of factors and controls allows for accurate in vivo cell quantification using MRI.
Area of Science:
- Biomedical Imaging
- Cellular Biology
- Nanotechnology
Background:
- Superparamagnetic iron oxide (SPIO) nanoparticles are used for cell labeling.
- Accurate quantification of SPIO-labeled cells in vivo is crucial for various applications.
Purpose of the Study:
- To demonstrate the feasibility of using MRI to quantify SPIO-labeled cells.
- To assess the impact of cell type and free iron on quantification accuracy.
Main Methods:
- Lymphocytes and 9L gliosarcoma cells were labeled with ferumoxides-protamine sulfate complex (FE-PRO).
- Cellular viability and iron concentration were measured.
- MRI (7T and 3T) was used to acquire T2-weighted images and R2 maps of phantoms and rat brains with labeled cells.
Main Results:
- Cellular viability and proliferation were unaffected by SPIO labeling.
- Strong linear correlations were observed between R2 values and both labeled cell numbers and free iron concentration.
- Regression lines differed between cell types, and free iron exhibited higher R2 values than labeled cells at equivalent iron concentrations.
Conclusions:
- MRI can quantify SPIO-labeled cells in vivo.
- Accurate quantification requires careful consideration of cell type, free iron, and appropriate control groups.
