MRI contrast agents toward cancer treatment: progress and perspectives

Magnetic resonance imaging (MRI) is a leading non-invasive imaging modality with high resolution and deep tissue penetration, and it has been widely used in clinical and preclinical cancer diagnosis and therapy. MRI contrast agents play an indispensable role in improving the imaging sensitivity and the contrast effect. This review first outlines the clinical significance of developing high-performance MRI contrast agents for cancer treatment, and summarizes the recent advances in four major categories: gadolinium (Gd)-based contrast agents, magnetic metal oxide nanomaterials, biomolecules-based contrast agents, and hybrid nanocomposites. Representative studies are selected to illustrate the structure-performance relationships at molecule level. The current challenges and future perspectives in this field are also critically discussed. This review is expected to stimulate further research efforts and promote the clinical translation of advanced MRI contrast agents for cancer theranostics.