R1 dispersion contrast at high field with fast field-cycling MRI

Contrast agents with a strong R1dispersion have been shown to be effective in generating target-specific contrast in MRI. The utilization of this R1field dependence requires the adaptation of an MRI scanner for fast field-cycling (FFC). Here, we present the first implementation and validation of FFC-MRI at a clinical field strength of 3 T. A field-cycling range of ±100 mT around the nominal B0field was realized by inserting an additional insert coil into an otherwise conventional MRI system. System validation was successfully performed with selected iron oxide magnetic nanoparticles and comparison to FFC-NMR relaxometry measurements. Furthermore, we show proof-of-principle R1dispersion imaging and demonstrate the capability of generating R1dispersion contrast at high field with suppressed background signal. With the presented ready-to-use hardware setup it is possible to investigate MRI contrast agents with a strong R1dispersion at a field strength of 3 T.