Microscopic Susceptibility-Induced Steady-State Perturbation: Theory and Experiment
Bieri O, Scheffler K
University of Basel, University Hospital
Development of models that describe susceptibility effects in a microvascular network in a Hahn spin-echo and gradient-echo type of experiment have a long history and are profoundly investigated. Although other type of measurement protocols such as steady state sequences may have a better sensitivity to mesoscopic paramagnetic structures, such protocols have not yet been investigated. A model, based on Monte Carlo simulations and experiments with microspheres is derived that describes microscopic susceptibility-based contrast in a balanced SSFP type of sequence prototypic for all steady state protocols. Susceptibility effects show up as an overall reduction in steady state amplitude that depends on the repetition time and susceptibility difference, as well as on relaxation times and on flip angle and finally, a scaling law will be given.