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Magnetic resonance chemical exchange saturation transfer imaging and nanotechnology
Author(s) -
Winter Patrick M.
Publication year - 2012
Publication title -
wiley interdisciplinary reviews: nanomedicine and nanobiotechnology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.175
H-Index - 72
eISSN - 1939-0041
pISSN - 1939-5116
DOI - 10.1002/wnan.1167
Subject(s) - paramagnetism , nanoparticle , nuclear magnetic resonance , chemistry , saturation (graph theory) , magnetic resonance imaging , pulse sequence , magnetization transfer , chemical physics , materials science , nanotechnology , condensed matter physics , physics , medicine , mathematics , combinatorics , radiology
Abstract Chemical exchange saturation transfer (CEST) agents and paramagnetic CEST (PARACEST) agents display bound water signals that exchange protons with the bulk water. CEST magnetic resonance imaging (MRI) relies on exchangeable protons that resonate at a chemical shift that is distinguishable from the bulk water signal. In some cases, paramagnetic chelates are utilized to shift the bound water frequency further away from the bulk water. Radiofrequency prepulses applied at the appropriate frequency can saturate the exchangeable protons, which transfer into the bulk water pool and lead to reduced equilibrium magnetization. Therefore, CEST and PARACEST agents allow the image contrast to be switched ‘on’ and ‘off’ by simply changing the pulse sequence parameters. One of the main limitations with this approach is the inherent insensitivity of MRI to CEST and PARACEST agents. Nanoscale carriers have been developed to improve the limit of detection for these agents, demonstrating the feasibility of in vivo molecular or cellular MRI based on CEST or PARACEST contrast. These carriers have been based on a number of different nanoparticle constructs, such as liposomes, dendrimers, polymers, adenovirus particles, and perfluorocarbon nanoparticles. The unique MRI properties of CEST and PARACEST nanoparticle systems have spawned research into an array of potential medical applications. WIREs Nanomed Nanobiotechnol 2012, 4:389–398. doi: 10.1002/wnan.1167 This article is categorized under: Diagnostic Tools > Diagnostic Nanodevices Therapeutic Approaches and Drug Discovery > Emerging Technologies Diagnostic Tools > In Vivo Nanodiagnostics and Imaging