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Magnetic field dependence of solvent proton relaxation rates induced by Gd3+ and Mn2+ complexes of various polyaza macrocyclic ligands: Implications for NMR imaging
- Source :
- CIÊNCIAVITAE, Scopus-Elsevier
- Publication Year :
- 1986
- Publisher :
- Wiley, 1986.
-
Abstract
- The magnetic field dependence of the solvent water proton longitudinal relaxation rate 1/T1 (the NMRD profile) has been measured for solutions of chelates of Gd3+ and Mn2+ ions with two different polyaza macrocyclic ligands: 1, 4, 7-triazacyclononane-N, N′, N″,-triacetic acid (NOTA) and 1, 4, 7, 10-tetraazacyclododecane-N, N′, N″, N‴,-tetraacetic acid (DOTA). Studies were carried out mainly near physiological pH, but the pH dependence was also examined in some cases. The results are compared with published data for complexes of Gd3+ and Mn2+ ions with ethylenediaminetetraacetic acid (EDTA) and diethylenetriaminepentaacetie acid (DTPA). Competition experiments for the NOTA and DOTA chelates with EDTA and DTPA were also performed. It is found that, over the field range in which NMR imaging is currently being done, different symmetries of otherwise similar chemical ligands can alter 1/T1 of solvent protons by factors of up to three. The ligand environment can influence the relaxation times of the electronic spin moments of the ions, as well as their coordination number, thereby changing both the inner and outer sphere contributions to the relaxivities of the complexes. The relevance of these results to questions of efficiency and toxicity of these chelates as agents for enhancement of contrast in NMR images is discussed. © 1986 Academic Press, Inc.
- Subjects :
- Magnetic Resonance Spectroscopy
Coordination number
Contrast Media
Gadolinium
Ethylenediaminetetraacetic acid
Cyclams
Heterocyclic Compounds, 1-Ring
Magnetics
chemistry.chemical_compound
Heterocyclic Compounds
Animals
Humans
DOTA
Radiology, Nuclear Medicine and imaging
Chelation
Edetic Acid
Chelating Agents
Manganese
Ligand
Relaxation (NMR)
Hydrogen-Ion Concentration
Pentetic Acid
Solvent
chemistry
Outer sphere electron transfer
Physical chemistry
Nuclear chemistry
Subjects
Details
- ISSN :
- 15222594 and 07403194
- Volume :
- 3
- Database :
- OpenAIRE
- Journal :
- Magnetic Resonance in Medicine
- Accession number :
- edsair.doi.dedup.....0948d52c1b3fb486b6b76832eda22346
- Full Text :
- https://doi.org/10.1002/mrm.1910030207