3D magnetic resonance microscopy of the ex vivo retina

3D-MR microscopy at 11.7T and 20 × 20 × 57 μm resolution was performed on formalin-fixed rat eyes with: (I) no contrast agent and (II) Gadodiamide (Omniscan) added to the fixative. Group I data showed generally poor contrast among layers. Group II data showed markedly better lamina-specific contrast with the nerve fiber + ganglion cell layer and inner nuclear layer being hypointense, and the inner plexiform, outer plexiform, outer nuclear layer, and the segments being hyperintense. The signal-to-noise ratio in group II was higher than group I, consistent with Gadodiamide acting as a T ₁-contrast agent. All major retinal layers were assigned and their thicknesses quantified with corroboration by histology. MR microscopy allows nondestructive examination of valuable specimens and could have applications in disease and in vivo.