Metal Complexes as MRI Contrast Enhancement Agents

摘要: Magnetic resonance imaging is one of the most efficient diagnostic modalities in clinical radiology and biomedical research. To enhance image contrast, paramagnetic complexes, mainly Gd3+ chelates, are used. Today, around third all medical MR images generated with use a contrast medium this number expected to increase development new applications agents. Recently, molecular has emerged as area aiming at non-invasive visualisation expression function bioactive molecules cellular level. Since any application requires specific probe, chemical approaches become increasingly important. In chapter, we discuss first proton relaxivity, parameter that directly translates effectiveness an MRI agent. Many microscopic factors, including hydration number, water exchange rate, rotational dynamics, well electron spin relaxation, influence relaxivity for complexes. We show how structure, charge or size chelate affects these factors. also review different strategies derived obtain high-relaxivity probes. Non-toxicity agents primordial their application; therefore address main physico-chemical aspects related vivo stability Gd3+-based agents, such thermodynamic kinetic inertness. The second part chapter devoted new-generation media, smart responsive capable reporting on environment tissues. Among huge systems reported field probes, focus only sensing pH, redox state metal ions. pathologies, stroke, infections, kidney disease cancer associated significant pH variations. Accurate, high resolution, mapping would be great interest not purposes but monitoring progression, choice response therapy. partial oxygen pressure, pO2, metabolic processes cells, its variation from normal values often indicates pathologies (ischemic diseases, strokes, tumors). As ions, several them play crucial role biological processes, whereas others toxic. Alteration concentration body can correlated states. Our objective here illustrate, via few selected examples Paramagnetic Chemical Exchange Saturation Transfer (PARACEST) major design principles coordination chemistry derive probes using lanthanide