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Positive contrast from cells labeled with iron oxide nanoparticles: Quantitation of imaging data
Author(s) -
Magnitsky Sergey,
Zhang Jinjin,
Idiyatullin Djaudat,
Mohan Geetha,
Garwood Michael,
Lane Nancy E.,
Majumdar Sharmila
Publication year - 2017
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.26585
Subject(s) - flip angle , iron oxide , iron oxide nanoparticles , mesenchymal stem cell , magnetic resonance imaging , imaging phantom , chemistry , cell , internalization , pulse sequence , nuclear magnetic resonance , biochemistry , pathology , nuclear medicine , medicine , physics , organic chemistry , radiology
Purpose Conventional T 2 ‐weighted MRI produces a hypointense signal from iron‐labeled cells, which renders quantification unfeasible. We tested a SWeep Imaging with Fourier Transformation (SWIFT) MRI pulse sequence to generate a quantifiable hyperintense signal from iron‐labeled cells. Methods Mesenchymal stem cells (MSCs) were labeled with different concentrations of iron oxide particles and examined for cell viability, proliferation, and differentiation. The SWIFT sequence was optimized to detect and quantify the amount of iron in the muscle tissue after injection of iron oxide solution and iron‐labeled MSCs. Results The incubation of MSCs with iron oxide and low concentration of poly‐L‐lysine mixture resulted in an internalization of up to 22 pg of iron per cell with no adverse effect on MSCs. Phantom experiments showed a dependence of SWIFT signal intensity on the excitation flip angle. The hyperintense signal from iron‐labeled cells or solutions was detected, and an amount of the iron oxide in the tissue was quantified with the variable flip angle method. Conclusions The SWIFT sequence can produce a quantifiable hyperintense MRI signal from iron‐labeled cells. The graft of 18 x 10 6 cells was detectable for 19 days after injection and the amount of iron was quantifiable. The proposed protocol simplifies the detection and provides a means to quantify cell numbers. Magn Reson Med 78:1900–1910, 2017. © 2017 International Society for Magnetic Resonance in Medicine.