Quantification of SPIO nanoparticles in vivo using the finite perturber method
Article first published online: 30 NOV 2010
Copyright © 2010 Wiley-Liss, Inc.
Magnetic Resonance in Medicine
Volume 65, Issue 5, pages 1461–1469, May 2011
How to Cite
Langley, J., Liu, W., Jordan, E. K., Frank, J. A. and Zhao, Q. (2011), Quantification of SPIO nanoparticles in vivo using the finite perturber method. Magn Reson Med, 65: 1461–1469. doi: 10.1002/mrm.22727
- Issue published online: 15 APR 2011
- Article first published online: 30 NOV 2010
- Manuscript Accepted: 20 OCT 2010
- Manuscript Revised: 5 OCT 2010
- Manuscript Received: 21 APR 2010
- quantitative imaging;
- finite perturber method;
- phase gradient mapping
The susceptibility gradients generated by super-paramagnetic iron oxide (SPIO) nanoparticles make them an ideal contrast agent in magnetic resonance imaging. Traditional quantification methods for SPIO nanoparticle-based contrast agents rely on either mapping T values within a region or by modeling the magnetic field inhomogeneities generated by the contrast agent. In this study, a new model-based SPIO quantification method is introduced. The proposed method models magnetic field inhomogeneities by approximating regions containing SPIOs as ensembles of magnetic dipoles, referred to as the finite perturber method. The proposed method was verified using data acquired from a phantom and in vivo mouse models. The phantom consisted of an agar solution with four embedded vials, each vial containing known but different concentrations of SPIO nanoparticles. Gaussian noise was also added to the phantom data to test performance of the proposed method. The in vivo dataset was acquired using five mice, each of which was subcutaneously implanted in the flanks with 1 × 105 labeled and 1 × 106 unlabeled C6 glioma cells. For the phantom data set, the proposed algorithm was generate accurate estimations of the concentration of SPIOs. For the in vivo dataset, the method was able to give estimations of the concentration within SPIO-labeled tumors that are reasonably close to the known concentration. Magn Reson Med, 2011. © 2010 Wiley-Liss, Inc.