Molecular factors that determine Curie spin relaxation in dysprosium complexes

P. Caravan, M. T. Greenfield, J. W.M. Bulte

Research output: Contribution to journalArticlepeer-review


Dysprosium complexes can serve as transverse relaxation (T2) agents for water protons through chemical exchange and the Curie spin relaxation mechanism. Using a pair of matched dysprosium(III) complexes, Dy-L1 (contains one inner-sphere water) and Dy-L2 (no inner-sphere water), it is shown that the transverse relaxation of bulk water is predominantly an innersphere effect. The kinetics of water exchange at Dy-L1 were determined by 17O NMR. Proton transverse relaxation by Dy-L1 at high fields is governed primarily through a large chemical shift difference between free and bound water. Dy-L1 forms a noncovalent adduct with human serum albumin which dramatically lengthens the rotational correlation time, τR, causing the dipole-dipole component of the Curie spin mechanism to become significant and transverse relaxivity to increase by 3-8 times that of the unbound chelate. These findings aid in the design of new molecular species as efficient r2 agents.

Original languageEnglish (US)
Pages (from-to)917-922
Number of pages6
JournalMagnetic resonance in medicine
Issue number5
StatePublished - 2001
Externally publishedYes


  • Albumin
  • Curie spin
  • Dysprosium
  • Human serum
  • Inner-sphere
  • Out-sphere
  • Relaxation
  • T contrast agent
  • Water exchange

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging

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