Heavy metal staining, a comparative assessment of gadolinium chloride and osmium tetroxide for inner ear labyrinthine contrast enhancement using X-ray microtomography

摘要

Conclusion: The use of both gadolinium chloride (GdCl3) and osmium tetroxide (OsO4) allowed for the visualization of the membranous labyrinth and other intralabyrinthine structures, at different intensities, as compared with the control sample. This initial comparison shows the advantages of GdCl3 in radiological assessments and OsO4 in more detailed anatomical studies and pathways of labyrinthine pathogenesis using X-ray microtomography (microCT). Objective: To assess an improved OsO4 staining protocol and compare the staining affinities against GdCl3. Methods: Guinea pig temporal bones were stained with either GdCl3 (2% w/v) for 7 days or OsO4 (2% w/v) for 3 days, and scanned in a microCT system. The post-scanned datasets were then assessed in a 3D rendering program. Results: The enhanced soft tissue contrast as presented in the temporal bones stained with either GdCl3 or OsO4 allowed for the membranous labyrinth to be visualized throughout the whole specimen. GdCl3-stained specimens presented more defined contours of the bone profile in the radiographs, while OsO4-stained specimens provided more anatomical detail of individual intralabyrinthine structures, hence allowing spatial relationships to be visualized with ease in a 3D rendering context and 2D axial slice images.