High resolution, contrast-enhanced X-ray microscopy of the ex vivo human cochlea: technical feasibility and biometric case analysis

BackgroundThe human cochlea is a fragile, spiral-shaped sensory organ for hearing that is deeply embedded within the dense otic capsule bone, making accurate post-mortem anatomical studies difficult when using conventional histological approaches requiring sectioning. X-ray microscopy (XRM) is a non-destructive radiological imaging modality that combines geometric and optical magnification to achieve high-resolution 3D visualization.MethodsHere, we evaluated the ability of XRM to resolve the entire inner ear, including delineating soft tissue and bony structures, in trimmed human temporal bones ex vivo following lumen perfusion with a reversible iodine-based contrast-enhancing solution. After optimizing contrast incubation conditions, XRM datasets were acquired, reconstructed, and used to generate 3D volume renderings of the inner ear.ResultsXRM enabled visualization of the entire cochlea and vestibular system, from millimeter-scale labyrinthine anatomy to submillimeter and micrometer-scale cochlear structures, including spiral ganglion nerve fiber bundles and sensory cell rows. Quantitative analysis in a representative case demonstrated an increasing width-to-height ratio of the organ of Corti from the basal to the apical cochlear turns, consistent with histology images and prior anatomical studies.ConclusionThese findings demonstrate that XRM provides high-resolution, sectioning-free ex vivo 3D visualization of human cochlear anatomy and may enable quicker and more faithful correlation of cochlear pathology with otologic disorders than traditional histology.