Magnetic resonance imaging of the galactosemic dog eye using magnetization transfer contrast

Magnetization transfer contrast (MTC) enhanced magnetic resonance (MR) imaging is a technique that generates high contrast images based on characteristic tissue differences resulting from the interaction of water and macromolecules. In this study, the feasibility of applying this technique to documenting the progression of osmotic sugar cataract formation was investigated in male beagles, initially 6 or 24 month old, fed a diet containing 30% galactose. MTC enhanced magnetic resonance imaging was periodically conducted on these animal's eyes at 2-Tesla. The lens MR images were compared to photographs obtained by photo-slit lamp and retroillumination photography. The MTC technique provided improved image details of the lens and anterior segment that documented osmotic changes from initial cortical vacuole formation to cortical and nuclear changes associated with advanced sugar cataracts. The latter could not be observed by photo-slit lamp or retroillumination photography.