Lanthanide contrast agents

The hydration state of lanthanide(III) chelates can be assessed by different techniques. Luminescence studies are widely used for Eu111 and Tb111 chelates (see Chapter 9.21).17 18 170 NMR chemical shift measurements in solution of lanthanide(III) (most often Dy or Gd) complexes can also give information on q.19 These techniques in the context of MRI contrast agent research have been reviewed in 2001.1... 

Although nuclear magnetic resonance (NMR) spectroscopy has been used to study a variety of lanthanide based systems like contrast agents for medical imaging applications, only a handful of studies on lanthanide SMMs using NMR have been performed to date. These include the neutral [Ln(Pc)2]°(Ln = Dy or Tb)... 

Her present research interests are focused onto the design, synthesis of new lanthanide complexes as contrast agents for magnetic resonance imaging (MRI), as well as the development of a novel series of pH and p02 indicators for 111 NMR spectroscopic imaging ( II-MRSI). More recently, she has been involved in synthesis and evaluation of nanostructurated contrast agents. 

MRI contrast agents. Therefore the possibility of combined diagnostic imaging and photodynamic therapy arises (324). Lanthanide texaphy-rin complexes are more kinetically stable than the porphyrin analogs. 

Bray KL (2001) High Pressure Probes of Electronic Structure and Luminescence Properties of Transition Metal and Lanthanide Systems. 213 1-94 Briicher E (2002) Kinetic Stabilities of Gadolinium(III) Chelates Used as MRI Contrast Agents. 221 103- 122... 

The following chapter reviews tissue-specific X-ray contrast agents, in particular liver-specific substances. Although many different approaches including hepatocyte and Kupffer-cell targeting utilizing iodinated compounds have been followed, no small molecule could be obtained that is effective and safe. Two different approaches, however, do seem to be feasible and will be followed in the future. These are extracellular iodinated X-ray contrast agents encapsulated into liposomes and liver-specific lanthanide chelates. 

Lanthanide complexes may also be employed as contrast agents in Magnetic Resonance Imaging (MRI), a non-invasive diagnostic tool... 

This is based on spatial nuclear magnetic resonance of water protons within the body. For a contrast agent to be effective, direct coordination of water molecules to the lanthanide is necessary to impart efficient relaxation of the water protons. Therefore, whilst this has been covered comprehensively in a number of recent reviews... 

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