Magnetic resonance imaging

Magnetic resonance imaging (MRI) is a powerful and versatile imaging modality for the noninvasive, in vivo characterization of biological systems. The relatively low tissue density and large number of air-tissue interfaces in lung present several unique challenges to its study by magnetic resonance (MR). Nonetheless, MR techniques have been developed to provide important insights into the structure and dynamics of lungs in humans and in small-animal models of lung disease. These methods include both conventional MRI of the hydrogen atoms in water in lung tissue and imaging of air spaces using hyperpolarized helium gas. Molecular imaging can provide important insights into biological processes at the cellular or subcellular level. The linking of specific targeted molecular agents with the superb anatomical resolution provided by MRI forms a particularly powerful combination. In this chapter, we provide an overview of MR molecular imaging and MRI of lung in both humans and small animals and discuss the prospects for the development of MR-based molecular imaging techniques in lungs.