Visualization of fluid flow pathways in wood by low-field 1H and 3He contrast MRI

A low-field Magnetic Resonance Imaging (MRI) technique was used for noninvasive studies of the internal structure of three types of wood, using water and 3He gas as contrast agents. In the conditions of steady state water flow through the sample, the fluid flow pathways were found to be mainly located in the late wood. A substantial increase in sensitivity, or equivalently, a decrease in experiment time was demonstrated, when the hyperpolarized 3He gas was used. The method opens new opportunities of studying a wide range of similar biologically permeable materials in a nondestructive way.