Elucidating structure and function in vivo with hybrid fluorescence and magnetic resonance imaging

While the mathematics, physics, and technology behind magnetic resonance (MR) and fluorescence image formation are distinctively different, the two modalities have significant complementary features to impart strong preclinical and clinical application synergies. Traditionally, hybrid MR and fluorescence imaging implied the use of a system where optical and MR signals can be concurrently acquired. In this case, the common geometry allows for the superposition of fluorescence images of cellular and subcellular processes onto anatomical and functional MR images. More recently, a different hybrid imaging paradigm is strongly evolving by utilizing hybrid MR-fluorescence nanoparticles. This approach offers a second paradigm of hybrid visualization where the common underlying contrast enables the coregistration of MR and fluorescence images acquired under different geometries. We review herein progress with the evolving field of multimodality MR and fluorescence imaging and discuss how these strategies offer a highly promising outlook in established and in novel preclinical and clinical applications.