High-contrast Background-free Magnetic Resonance Molecular Imaging

One of the holy grails in cancer detection and therapy is to simultaneously image and deliver drugs to the tumor site using a safe nanoparticle. Liposomes are a well-known safe and stable nanoparticles that can be loaded with a drug and suitable contrast agent for magnetic resonance imaging (MRI). However, the loading of a contrast agent such as gadolinium in liposomes generally results in poor contrast and various artifacts in in vivo experiments, compared to free gadolinium chelate experiments. Current work demonstrates the effective filtering of artifacts and contrast enhancement to obtain high quality images of the tumor sites in mouse models using paramagnetic liposome nanoparticles as contrast agent, a novel pulse sequence in active-feedback MRI, and nonlinear fitting. Our results show a significant improvement in eliminating artifacts and increasing contrast compared to the standard MRI techniques, and a close correlation with histopathology and inductively coupled mass spectrometry results. This newly developed protocol could be used for any paramagnetic nanoparticle to improve detection sensitivity. We expect this methodology to produce similar improvements in human imaging, having the potential to significantly improve early tumor detection in clinical practice and opening up the possibility of its theranostic use.