MACE: Contrast-enhanced magnetic resonance angiography

• Research unit: EU RFP
• Project number: 95.0258-1

Key words (English)

Magnetic Resonance Imaging; Contrast Agents; Angiography; Relaxometry; Superparamagnetic Partides; Paramagnetic Complexes

Alternative project number (English)

EU project number: BMH4CT960051

Research programs (English)

EU-programme: 4. Frame Research Programme - 4.2 Agriculture and agroindustry

Short description (English)

See abstract

Further information (English)

Full name of research-institution/enterprise:
EPF Lausanne
Laboratoire de Chimie Inorganique et Bioinorganique
EPFL - FSB/ISIC - LCIB

Partners and International Organizations (English)

Université de Mons-Hainaut (B); Université de Delft (NL); Kantonspital Basel (CH); Universidad de Coimbra (P); STELLAR s.n.c. de SYKORA (I); Universita degli Studi di Torino (I); University of Oslo (N); NYCOMED IMAGING A/S (N)

Abstract (English)

The efficiency of MRI contrast agents is influenced by several factors. Their determination and the understanding of the mechanisms governing proton relaxivity is crucial for their development. A detailed study on the effects of structural changes of the ligand has shown that only changes in the co-ordinating groups have strong effects on the water exchange of the Gd(III) complex. Complexes with a hydration equilibrium may have remarkably faster water exchange which is a great advantage in MRI applications. For the first time, we have directly assessed water exchange on a Gd(III) chelate attached to a protein.
Gd(III)-based linear polymers are often proposed in the aim of increasing the rotational correlation time, hence the relaxivity of the agent. For a series of linear polymers with hydrophobic chains we have separated the contribution of local and global motions, and proved that, contrary to former assumptions, global motions can significantly contribute to relaxivity.
Monomeric complexes forming micellar aggregations represent a relatively simple but efficient way of attaining high relaxivities. Several systems have been or are continuously characterized, and based on the results, new agents are under development.
Variable field EPR measurements on actual agents and on model compounds have allowed for improving the theory of electronic relaxation. They have also shown the importance of intramolecular interactions for complexes with several Gd ions in a dose proximity.
The Fast Field Cycling Stelar NMR relaxometer, installed in our group in 1997, is a unique instrument of this kind in Switzerland which represents a useful tool a in contrast agent research

References in databases (English)

Swiss Database: Euro-DB of the
State Secretariat for Education and Research
Hallwylstrasse 4
CH-3003 Berne, Switzerland
Tel. [phone]
Swiss Project-Number: 95.0258-1