Study of kinetics of 19F-MRI using a fluorinated imaging agent (~(19)FIT) on a 3T clinical MRI system

摘要

Purpose To use ~(19)F imaging tracer (~(19)FIT-27) to evaluate kinetics in major organs. Introduction Kinetics studies using proton MRI are difficult because of low concentration of ~(19)FIT-27 protons relative to background water protons. Because there is no background source of ~(19)F NMR in a biological body, ~(19)F may be an ideal nucleus to directly trace ~(19)FIT-27. However, there are several challenges for reliable ~(19)F MR imaging and spectroscopy, particularly with clinical whole-body MRI systems, which include low concentrations and long ~(19)F T_1. Methods and materials We performed a dynamic ~(19)F MRI study on mice at a 3T whole-body MRI system using a homemade transmit/receive (Tx/Rx) switch and a Tx/Rx volume RF coil. We used a newly developed fluorine imaging agent, which has 27 identical fluorine atoms with identical chemical shift, a relatively short T_1, and high hydrophilicity. Basic kinetics parameters were estimated from the ~(19)F signal-time curve. Results and discussions Resultant fluorine images show fairly high spatial (3 × 3 × 3 mm~3) and temporal resolutions. Biodistribution and kinetics of ~(19)FIT-27 are obtained via ~(19)F images for major uptake organs. Conclusions Whole-body dynamic ~(19)F MRI of newly developed ~(19)FIT-27 in mice was obtained with fairly high spatial and temporal resolutions on a 3T clinical MRI system. The present study demonstrates the feasibility of ~(19)F MRI using our newly developed compound to investigate major organ kinetics.