title: On the strong field dependence and nonlinear response to gadolinium contrast agent of proton transverse relaxation rates in dairy cream.
abstract: Dairy cream, as a suspension of lipid droplets in water, is a potentially useful magnetic resonance imaging (MRI) phantom material and an interesting material for studying fundamental relaxation mechanisms. Here we report a strong increase in the transverse relaxation rates with field strength for both the water and lipid protons in dairy cream. Also, studies at 4.7 T reveal a nonlinear response of transverse relaxation rates with increasing concentration of a common gadolinium (Gd)-based contrast agent, including an initial decrease of water relaxation rates as measured with Hahn spin echoes at the lower Gd concentrations. The results are treated within the framework of a model in which the magnetic susceptibility difference between the lipid droplets and the aqueous phase plays the prominent role for transverse relaxation. Second-order polynomial fits of the water proton transverse relaxation rate dependence on field strength and on Gd concentration at 4.7 T provided experimental parameters from which model parameters are extracted and compared with expectations available from the literature.
authors.affiliation: Department of Radiology, Children's Hospital, Boston, MA 02468, USA. rmulkern@yahoo.com
authors.forename: Robert V
authors.initials: RV
authors.lastname: Mulkern
authors.forename: Yin P
authors.initials: YP
authors.lastname: Hung
authors.forename: Zaid
authors.initials: Z
authors.lastname: Ababneh
authors.forename: Stephan E
authors.initials: SE
authors.lastname: Maier
authors.forename: Alan B
authors.initials: AB
authors.lastname: Packard
authors.forename: Mehmet C
authors.initials: MC
authors.lastname: Uluer
authors.forename: Daniel F
authors.initials: DF
authors.lastname: Kacher
authors.forename: Giulio
authors.initials: G
authors.lastname: Gambarota
authors.forename: Stephan
authors.initials: S
authors.lastname: Voss
mesh_terms: D003287:Contrast Media; D003611:Dairy Products / Q000032:analysis*; D005682:Gadolinium / Q000032:analysis / Q000737:chemistry*; D008055:Lipids / Q000032:analysis / Q000737:chemistry*; D008279:Magnetic Resonance Imaging / Q000295:instrumentation* / Q000379:methods*; D017711:Nonlinear Dynamics; D019047:Phantoms, Imaging; D011522:Protons; D014867:Water / Q000032:analysis / Q000737:chemistry*
chemical_list: D003287:Contrast Media; D008055:Lipids; D011522:Protons; D014867:Water; D005682:Gadolinium