Gadolinium chloride as a contrast agent for imaging wood composite components by magnetic resonance

Abstract

Abstract Although paramagnetic contrast agents have an established track record in medical uses of magnetic resonance imaging (MRI), only recently has a contrast agent been used for enhancing MRI images of solid wood specimens. Expanding on this concept, wood veneers were treated with a gadolinium-based contrast agent and used in a model system comprising three-ply plywood panels fabricated from two untreated veneers and one treated veneer. The limited degree of effect imparted by the contrast agent for specimens in a water-saturated state likely resulted from contrast agent losses due to leaching during the prerequisite water saturation process. Specimens were also analyzed in the air-dry state using a non-conventional MRI sequence. This allowed what appears to be the first reported visualization of earlywood and latewood bands in MR images for air-dry wood specimens. Observation of significant signal dropout for the gadolinium-treated veneer demonstrated the first successful use of a contrast agent to manipulate the signal intensity of a wood component within a composite structure. This technique shows promise for non-destructive two- and three-dimensional assessments of wood component (e.g., veneers, flakes, particles) distributions and orientations in wood composites.