Chemical exchange saturation transfer

Beside classical MRI, based on the measurement of water abundance in tissues and variation of its relaxation rates, other techniques such as chemical exchange saturation transfer (CEST) and its improved form using paramagnetic compounds (PARACEST) are currently investigated to improve the potential of MRI diagnosis. 

Since the electron densities near the hydrogen bond of 267, 328 and 329 are about the same and since the contribution of chemical exchange (saturation transfer) is small, the following is the most reasonable cause for the downfield shift of the 5-OH signal on prenylation at the 6-position The 6-prenyl group interferes with rotation of the bond between the C-5 carbon and the C-5 hydroxyl group and/or distorts the... 

In this chapter, we deal with Gd " " complexes applied as Ti agents in MRI. In the first part of the chapter, we discuss the different relaxation mechanisms and how supramolecular approaches can be used to optimize the efficacy of Gd " "-based contrast agents. Nontoxicity is of prime importance for in vivo nse of metal chelates therefore, we also shortly assess some aspects related to their thermodynamic stability and kinetic inertness. We include a short infioduction to CEST (chemical exchange saturation transfer) agents, a new class of lanthanide-based MRI probes, and discnss how supramolecular systems, particularly liposomes, can be beneficial to decrease the sensitivity limit of CEST detection. In the second part of the chapter. 

Chemical exchange saturation transfer (CEST) agents... 

PARACEST Paramagnetic Chemical Exchange Saturation Transfer TPA Two-Photon Absorption... 

Boronic acids have been used in the development of surface plasmon resonance (SPR) [174,175] quartz crystal microbalance (QCM) sensors [174,176,177], Faradaic impedance spectroscopy [177], ion-sensitive field effect transistors (ISFET) [178], and chemical exchange saturation transfer (CEST) contrast agents in magnetic resonance imaging (MRl) [179]. The swelling of phenylboronic add polymers has also been used to control the release of insulin (180,181]. 

Aime S, Barge A, Belli Castelli D et al. Paramagnetic lanthanide(III) complexes as pH-sensitive chemical exchange saturation transfer (CEST) contrast agents for MRI apphcations. Magn Reson Med 2002 47 639-648. 

Hammell J, Buttarazzi L, Huang C-H, Morrow JR. Eu(III) complexes as anion-responsive luminescent sensors and paramagnetic chemical exchange saturation transfer agents. Inorg Chem. 2011 50 4857 867. 

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