title: Blood NMR relaxation in the rotating frame: mechanistic implications.
abstract: The rotating frame nuclear magnetic resonance relaxation rate R(1rho) in the blood and cell lysate was studied at 4.7T to provide reference values for in vivo modeling and to address the mechanisms contributing to net relaxation. A strong dependence on oxygenation, hematocrit, and spin lock field strength B(1) (0.2-1.6G) was observed in whole blood, whereas in lysate the effects were severely attenuated. The results were further compared to transverse relaxation rate R(2). A good agreement in low-field asymptotes of these two relaxation rates was found. R(1rho) field dispersion was fitted to Lorenzian line shape and resulted in correlation times around 40 micros. The dispersion behavior was related to motional properties of intracellular hemoglobin and effects of susceptibility shift interface across the cell membrane induced by compartmentalization of Hb into cells in blood.
authors.affiliation: Department of Biomedical NMR and National Bio NMR Facility, A.I. Virtanen Institute, University of Kuopio, Kuopio, Finland.
authors.forename: M
authors.initials: M
authors.lastname: Johanna Silvennoinen
authors.forename: Mikko I
authors.initials: MI
authors.lastname: Kettunen
authors.forename: Chekesha S
authors.initials: CS
authors.lastname: Clingman
authors.forename: Risto A
authors.initials: RA
authors.lastname: Kauppinen
mesh_terms: D000818:Animals; D002417:Cattle; D002462:Cell Membrane / Q000378:metabolism; D004912:Erythrocytes / Q000378:metabolism; D006454:Hemoglobins / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D010100:Oxygen / Q000378:metabolism; D013997:Time Factors
chemical_list: D006454:Hemoglobins; D010100:Oxygen