Quantitative measurement of tympanic membrane structure and symmetry with optical coherence tomography in normal human subjects.

Abstract

Significance: Early detection of ear pathology is essential for preventing hearing loss, yet the sensitivity of otoscopic examinations by primary care providers during annual physicals remains low. Optical coherence tomography (OCT) offers a promising alternative for detailed imaging of the tympanic membrane (TM) and middle ear (ME), providing the potential for early identification of ear disease.

Aim: We aim to develop a quantitative method for assessing symmetry between the right and left ears and to establish a baseline for this approach in normal subjects.

Approach: Volumetric OCT images were acquired from 12 normal subjects using a custom hand-held OCT otoscope. A volume registration and fusion method was applied to expand the TM field of view, followed by TM thickness measurement and generation of 3D thickness maps. The symmetry between left and right TMs was quantitatively analyzed using the Dice similarity coefficient.

Results: The average TM thickness was measured as $73.89\pm 14.79\mu m$ for left ears and $70.72\pm 11.58\mu m$ for right ears, with no statistically significant difference at the 0.05 level. The symmetry analysis revealed a mean similarity coefficient of $0.79\pm 0.02$ between left and right ears among the 12 normal subjects.

Conclusions: OCT imaging enables quantitative assessment of TM thickness and symmetry, offering a baseline for identifying early ear pathologies.