Measuring Changes in Brain Manganese or Iron Using Magnetic Resonance Imaging (MRI)

There are many diseases of the brain in which the transition metals manganese (Mn) and iron (Fe) are known or suspected to play a role. The magnetic resonance imaging (MRI) signal is sensitive to these paramagnetic metals; hence, quantitative MRI (qMRI) can be used to measure changes in Mn or Fe concentrations in vivo in animal models of brain disease. Here, we specifically describe how to measure changes in Mn in the brain from qMRI measurements of the longitudinal relaxation rate, R1, in rats at a magnetic field strength of 7 T. We further discuss how to extend the method to measure changes in Mn or Fe from other qMRI parameters.