Quantifications of in vivo labeled stem cells based on measurements of magnetic moments

Abstract

Cells labeled by super paramagnetic iron-oxide (SPIO) nanoparticles are more easily seen in gradient echo MR images, but it has not been shown that the amount of nanoparticles or the number of cells can be directly quantified from MR images. This work utilizes a previously developed and improved Complex Image Summation around a Spherical or Cylindrical Object (CISSCO) method to quantify the magnetic moments of several clusters of SPIO nanoparticle labeled cells from archived rat brain images. With the knowledge of mass magnetization of the cell labeling agent and cell iron uptake, the number of cells in each nanoparticle cluster can be determined. Using a high pass filter with a reasonable size has little effect on each measured magnetic moment from the CISSCO method. These procedures and quantitative results may help improve the efficacy of cell-based treatments in vivo.

Quantitative [Fe]MRI determination of the dynamics of PSMA‐targeted SPIONs discriminates among prostate tumor xenografts based on their PSMA expression

“…The macrophage density, and by inference, the severity of the infection could then be judged with the aid of [Fe] determinations in the affected tissues. Other potential applications of [Fe]MRI could be to the measurement of amyloid plaque density or microglial activation in Alzheimer's dementia, or the quantitation of magnetically labeled stem cells …”