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Ultrashort T 2 * relaxometry for quantitation of highly concentrated superparamagnetic iron oxide (SPIO) nanoparticle labeled cells
Author(s) -
Liu Wei,
Dahnke Hannes,
Rahmer Juergen,
Jordan E. Kay,
Frank Joseph A.
Publication year - 2009
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.21923
Subject(s) - relaxometry , superparamagnetism , nanoparticle , iron oxide nanoparticles , chemistry , iron oxide , nuclear magnetic resonance , nanotechnology , materials science , magnetic resonance imaging , physics , medicine , radiology , organic chemistry , magnetization , spin echo , quantum mechanics , magnetic field
A new method was developed to measure ultrashort T 2 *relaxation in tissues containing a focal area of superparamagnetic iron oxide (SPIO) nanoparticle‐labeled cells in which the T 2 *decay is too short to be accurately measured using regular gradient echo T 2 *mapping. The proposed method utilizes the relatively long T 2 relaxation of SPIO‐labeled cells and acquires a series of spin echo images with the readout echo shifted to sample the T 2 *decay curve. MRI experiments in phantoms and rats with SPIO‐labeled tumors demonstrated that it can detect ultrashort T 2 *down to 1 ms or less. The measured T 2 *values were about 10% higher than those from the ultrashort TE (UTE) technique. The shorter the TE, the less the measurements deviated from the UTE T 2 *mapping. Combined with the regular T 2 *mapping, this technique is expected to provide quantitation of highly concentrated iron‐labeled cells from direct cell transplantation. Magn Reson Med, 2009. © 2009 Wiley‐Liss, Inc.