Premium
Positive contrast imaging of iron oxide nanoparticles with susceptibility‐weighted imaging
Author(s) -
Eibofner Frank,
Steidle Günter,
Kehlbach Rainer,
Bantleon Rüdiger,
Schick Fritz
Publication year - 2010
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.22498
Subject(s) - imaging phantom , magnetic resonance imaging , nuclear magnetic resonance , iron oxide , contrast (vision) , superparamagnetism , materials science , pixel , signal (programming language) , iron oxide nanoparticles , nanoparticle , chemistry , magnetic field , optics , nanotechnology , physics , computer science , radiology , medicine , magnetization , quantum mechanics , metallurgy , programming language
Superparamagnetic iron oxide particles can be utilized to label cells for immune cell and stem cell therapy. The labeled cells cause significant field distortions induced in their vicinity, which can be detected with magnetic resonance imaging (MRI). In conventional imaging, the signal voids arising from the field distortions lead to negative contrast, which is not desirable, as detection of the cells can be masked by native low signal tissue. In this work, a new method for visualizing magnetically labeled cells with positive contrast is proposed and described. The technique presented is based on the susceptibility‐weighted imaging (SWI) post‐processing algorithm. Phase images from gradient‐echo sequences are evaluated pixel by pixel, and a mask is created with values ranging from 0 to 1, depending on the phase value of the pixel. The magnitude image is then multiplied by the mask. With an appropriate mask function, positive contrast in the vicinity of the labeled cells is created. The feasibility of this technique is proved using an agar phantom containing superparamagnetic iron oxide particles–labeled cells and an ex vivo bovine liver. The results show high potential for detecting even small labeled cell concentrations in structurally inhomogeneous tissue types. Magn Reson Med, 2010. © 2010 Wiley‐Liss, Inc.