ABSTRACT
Paramagnetic chemical exchange saturation transfer (paraCEST)
agents are, in the terminology of the late 1970s, aqueous nuclear
magnetic resonance (NMR) shift reagents that alter the frequency
of the exchanging proton resonance so that they are further away
from the bulk water resonance. As the name indicates, paraCEST
contrast is generated as a result of transfer of saturated proton spins
originating on a paramagnetic species (μeff = 0) into the larger pool of water proton spins and detected by magnetic resonance imaging
(MRI). This spin transfer typically utilizes exchangeable protons in
a paramagnetic metal ion complex in the form of –NH (amide),
–NH2 (amine), or –OH (hydroxyl) that slowly exchange with the bulk
Figure 11.1 Structure of Ln DOTA-(gly)−4 . Arrows indicate exchangeable protons from either amides or bound water.
