Optical Coherence Tomography as a Tool for Quantitative Imaging of the Tympanic Membrane and Middle Ear.

Objective: Advances in optical coherence tomography have improved diagnostic imaging for otologic pathologies. We investigated handheld OCT (HHOCT) otoscopic device's ability to quantitatively analyze the middle ear and provide valuable information for the management of middle ear pathologies.

Study Design: Cross-sectional cohort.

Methods: Eleven healthy patients, 5 patients with unilateral pathology, 6 patients with retraction pockets, and 1 patient undergoing ossiculoplasty were imaged using HHOCT in the clinic. Middle ear distances and retraction pocket depth were calculated using OCT volumes and compared to those on CT and in literature. Partial ossicular replacement prosthesis length was calculated before surgery and compared to the length chosen by an expert otologist. Data were characterized using descriptive statistics and paired t-tests. Volumes were analyzed and postprocessed using Amira (Thermofisher Scientific, Waltham, MA) and Fiji (NIH).

Results: HHOCT could image and obtain quantitative measurements of the middle ear at the point of care with greater resolution and precision than traditional imaging modalities. Mean incus diameter on OCT was 0.728 ± 0.089 mm, in agreement with cadaver studies. Measured middle ear distances and retraction pocket depths were not statistically significantly different from those measured on CT. The predicted prosthesis size for the ossiculoplasty patient was 2.46 mm, closely matching the 2-mm length chosen by an expert otologist.

Conclusion: OCT can provide reliable measurements of the tympanic membrane and middle ear structures not readily available through traditional imaging modalities. Pre- or intrasurgical measurements with OCT may be beneficial for guidance on size and placement of ossicular prosthetics and may improve hearing outcomes.