ABSTRACT
Novel MR imaging techniques have the ability to directly evaluate pulmonary blood flow and ventilation. This chapter examines MR techniques for the evaluation of pulmonary blood flow and ventilation, and discusses research and potential clinical applications. MR imaging is a widely available and accepted clinical imaging technique. Conventional proton MR imaging relies on the differences in the magnetic properties of tissues to produce contrast in the images. Regional pulmonary blood flow within the lung parenchyma was assessed simultaneously using both bolus tracking MR and colored microspheres. The basic principle for noncontrast techniques is that MR signal from stationary lung tissue is eliminated and signal from flowing blood produces an image. Hyperpolarized gases are new type of MR contrast agent in which a high degree of nuclear polarization is achieved outside of the MR scanner using a variety of techniques. A number of studies using hyperpolarized gas MRI have been reported in asthmatics.
