Open AccessDendritic PARACEST contrast agents for magnetic resonance imaging
Author(s) -
Pikkemaat J.A.,
Wegh R.T.,
Lamerichs R.,
van de Molengraaf R.A.,
Langereis S.,
Burdinski D.,
Raymond A.Y.F.,
Janssen H.M.,
de Waal B.F.M.,
Willard N.P.,
Meijer E.W.,
Grüll H.
Publication year - 2007
Publication title -
contrast media & molecular imaging
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.714
H-Index - 50
eISSN - 1555-4317
pISSN - 1555-4309
DOI - 10.1002/cmmi.149
Subject(s) - dendrimer , chemistry , gadolinium , amide , imine , nuclear magnetic resonance , magnetic resonance imaging , polymer chemistry , organic chemistry , medicine , physics , radiology , catalysis
MRI contrast agents based on chemical exchange‐dependent saturation transfer (CEST), such as Yb(III)DOTAM complexes, are highly suitable for pH mapping. In this paper, the synthesis of Yb(III)DOTAM‐functionalized poly(propylene imine) dendrimers is described. The applicability of these dendritic PARACEST MRI agents for pH mapping has been evaluated on a 7 T NMR spectrometer and on a 3 T clinical MRI scanner. As expected, based on the different numbers of exchangeable amide protons, the lowest detectable concentration of the first and third generation dendritic PARACEST agents is by a respective factor of about 4 and 16 lower than that of a mononuclear reference complex. The pH dependence of the CEST effect observed for these compounds depends on the generation of the poly(propylene imine) dendrimer. Upon going to higher generations of the Yb(III)DOTAM‐terminated dendrimer, a shift of the maximum CEST effect towards lower pH values was observed. This allows for a fine‐tuning of the responsive pH region by varying the dendritic framework. Copyright © 2007 John Wiley & Sons, Ltd.