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Human whole blood 1 H 2 O transverse relaxation with gadolinium‐based contrast reagents: Magnetic susceptibility and transmembrane water exchange
Author(s) -
Wilson Gregory J.,
Springer Charles S.,
Bastawrous Sarah,
Maki Jeffrey H.
Publication year - 2017
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.26284
Subject(s) - dephasing , chemistry , relaxation (psychology) , nuclear magnetic resonance , gadolinium , extracellular , magnetic resonance imaging , spin–lattice relaxation , rotational correlation time , electron paramagnetic resonance , analytical chemistry (journal) , physics , condensed matter physics , medicine , chromatography , biochemistry , organic chemistry , nuclear quadrupole resonance , radiology
Purpose To characterize transverse relaxation in oxygenated whole blood with extracellular gadolinium‐based contrast reagents by experiment and simulation. Methods Experimental measurements of transverse 1 H 2 O relaxation from oxygenated whole human blood and plasma were made at 1.5 and 3.0 Tesla. Spin‐echo refocused and free‐induction decays are reported for blood and plasma samples containing four different contrast reagents (gadobenate, gadoteridol, gadofosveset, and gadobutrol), each present at concentrations ranging from 1 to 18 mM (i.e., mmol (contrast reagent (CR))/L (blood)). Monte Carlo simulations were conducted to ascertain the molecular mechanisms underlying relaxation. These consisted of random walks of water molecules in a large ensemble of randomly oriented erythrocytes. Bulk magnetic susceptibility (BMS) differences between the extra‐ and intracellular compartments were taken into account. All key parameters for these simulations were taken from independent published measurements: they include no adjustable variables. Results Transverse relaxation is much more rapid in whole blood than in plasma, and the large majority of this dephasing is reversible by spin echo. Agreement between the experimental data and simulated results is remarkably good. Conclusion Extracellular field inhomogeneities alone make very small contributions, whereas the orientation‐dependent BMS intracellular resonance frequencies lead to the majority of transverse dephasing. Equilibrium exchange of water molecules between the intra‐ and extracellular compartments plays a significant role in transverse dephasing. Magn Reson Med 77:2015–2027, 2017. © 2016 International Society for Magnetic Resonance in Medicine