Flow-enhanced off-resonance saturation for remote detection of iron-based contrast agents.

A switchable contrast mechanism, flow enhanced off-resonance saturation, is presented. This technique combines the effects of flow and off-resonance saturation for remote detection of iron oxide contrast agents incorporated into a vessel wall. Initial results from phantom experiments are presented and show the feasibility of this method. A specific saturation contrast could be observed. This contrast mechanism is highly dependent on field homogeneity and spectral selectivity of the off-resonance saturation pulses. The contrast scales directly with the pulse offset of the used saturation pulses, the flow velocity in the vessel, and the duration of the off-resonance saturation module prior to the imaging sequence. This technique has the potential to detect iron-loaded atherosclerotic plaques in future in vivo applications.