title: The influence of pulse sequence on the relaxation effects of superparamagnetic iron oxide contrast agents.
abstract: The effects of different pulse sequences and timing parameters on the increase in transverse relaxation rate produced by superparamagnetic iron oxide particles have been studied. Gradient-echo, single spin-echo, and multiple-echo images recorded at 2.0 T were used to evaluate the reduction in signal intensity per unit concentration of iron oxide for different echo times and in different media. For the same echo time, gradient-echo sequences were found to be more than twice as sensitive to the effects of the agent as single spin-echo imaging sequences, while multiple-echo sequences were much less affected than either. Using measurements of the relative effects on different sequences, the contributions of different relaxation mechanisms have been quantified.
authors.affiliation: Department of Diagnostic Radiology, Yale University School of Medicine, New Haven, Connecticut.
authors.forename: S
authors.initials: S
authors.lastname: Majumdar
authors.forename: S S
authors.initials: SS
authors.lastname: Zoghbi
authors.forename: J C
authors.initials: JC
authors.lastname: Gore
mesh_terms: D003287:Contrast Media; D005290:Ferric Compounds; D008279:Magnetic Resonance Imaging; D008962:Models, Theoretical
chemical_list: D003287:Contrast Media; D005290:Ferric Compounds; C001215:ferrite; C000499:ferric oxide