Crushed Early Acquisition Spin Echo (CEASE): A Novel Technique for Positive Contrast and Spectroscopic Imaging of Superparamagnetic Particles

Bernard MCW Siow¹, Aiqing Chen², Gavin Clowry², Li Sun², Andrew M. Blamire¹

Imaging of iron oxide particles with T2* weighted scans provides negative contrast, however, in biological samples other hypointense regions are likely to be present. Positive contrast methods generate contrast that is more specific to iron oxide particles. Here we present a novel sequence that provides positive contrast and provides spectroscopic imaging: The CEASE sequence eliminates background signal by crushing macroscopic magnetisation and rephases spins local to the iron oxide particles. We have shown that it provides positive contrast and spectroscopic imaging in a phantom containing MPIO and an ex-vivo rat brain with stem cells that have been labelled with MPIO.