High-resolution imaging of the human cochlea through the round window by means of optical coherence tomography

Human cochlea is deeply embedded in the temporal bone and surrounded by a thick otic capsule, rendering its internal structure inaccessible for direct visualization. Clinical imaging techniques fall short in their resolution for imaging of the intracochlear structures with sufficient detail and this results in lacking guidance for safe placement of the inner ear therapies inside the cochlea. In the past decades, optical coherence tomography (OCT) has proven valuable for non-invasive, high-resolution, cross-sectional imaging of tissue microstructure in various fields of medicine. There is an upcoming interest for OCT imaging of the cochlea, which so far was mostly carried out in small animals. In this temporal bone study, we focused on high-resolution imaging in the human cochlea. The cochlea was approached through mastoidectomy and posterior tympanotomy, standard surgical procedures in clinical practice. Subsequently, high-resolution images of the cochlear ‘hook region’ were acquired through intact round window membrane in four cadaveric human temporal bones with spectraldomain OCT imaging system from Thorlabs. We will discuss the qualitative and quantitative characteristics of intracochlear structures on OCT images.