Fusion of Middle Ear Optical Coherence Tomography and Computed Tomography.

Abstract

Importance: Middle ear optical coherence tomography (OCT) imaging in patients has not previously been directly compared with a standard of care clinical 3-dimensional imaging technology, such as computed tomography (CT).

Objective: To qualitatively compare the capabilities of middle ear OCT with CT in normal and pathological ears on representative slices in coregistered OCT and CT datasets.

Design, setting, and participants: This case series included 3 patients and 3 ears: 1 normal middle ear, 1 ear affected by traumatic injury, and 1 ear with cholesteatoma. The ears were imaged with both OCT and high-resolution clinical temporal bone CT. Participants were drawn from the patient population of a tertiary otology clinic. CT and OCT images were aligned using rigid coregistration with manual landmark selection. Data were collected from January 2022 to April 2023, and data were analyzed from February 2022 to December 2023.

Main outcomes and measures: Images were analyzed qualitatively for field of view (FOV), resolution, shadowing, artifacts, soft tissue and bony tissue contrast, and presentation of diagnostically important features.

Results: In the 3 imaged ears, OCT was capable of visualizing many of the important features indicative of middle ear pathology. Compared with CT, OCT exhibited a limited FOV largely confined to the mesotympanum and subject to shadowing from bony structures. However, OCT could resolve soft tissue features that were not readily apparent in the CT images to have a higher resolution than CT and to provide excellent anatomical fidelity with CT, which allowed OCT images to be accurately coregistered with CT images.

Conclusions and relevance: In this case series, while OCT was not capable of replacing CT due to its limited FOV and inability to image through thick bony tissues, it visualized signs of pathology, including some soft tissue features, that are difficult to visualize with CT. Given OCT's ability to image in real time, its compatibility with in-office imaging, and its lack of ionizing radiation, it may, despite its limitations compared with CT, be an appealing imaging modality for many applications in middle ear diagnostics.