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

TL;DR

This paper demonstrates the first implementation of fast field-cycling MRI at 3 T, enabling the use of R1 dispersion contrast agents for target-specific imaging with a novel hardware setup.

Contribution

It introduces a new hardware configuration for fast field-cycling MRI at 3 T and validates its effectiveness with contrast agents and R1 dispersion imaging.

Findings

Successful validation with iron oxide nanoparticles

Demonstration of R1 dispersion contrast at 3 T

Suppressed background signal in high-field R1 dispersion imaging

Abstract

Contrast agents with a strong $R_1$ dispersion have been shown to be effective in generating target-specific contrast in MRI. The utilization of this $R_1$ field dependence requires the adaptation of a 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 $\pm$100 mT around the nominal $B_0$ field 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 $R_1$ dispersion imaging and demonstrate the capability of generating R1 dispersion 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 R1 dispersion at a field strength of 3 T.