Manganese: a new contrast agent for lung imaging?

Lung parenchyma remains one of the most difficult tissues to be imaged by means of magnetic resonance imaging (MRI). Several MRI techniques are routinely used for lung imaging. However, manganese-enhancement MRI (MEMRI) technique has not been associated with pulmonary MRI. Here, we evaluated T(1) -enhancement in the rat lung after a manganese instillation, using a 4.7 T magnet with a radial ultrashort echo time sequence. Our data showed that the signal intensity was increased in lungs receiving a manganese solution compared with a control solution to the lungs. MR signal enhancements above 30% were measured in lung parenchyma following 200 µl instillation of a 1 mm manganese chloride solution. MEMRI, therefore, may be a useful novel tool for enhancing signal intensity and image contrast in lung tissue.