Early diagnosis of ear disorders is difficult in part because patients do not seek out an otologist until they have significant hearing loss. Early detection could happen in the primary care provider’s office, however the sensitivity of an otoscopic examination by a primary care provider during an annual physical is very low. On the other hand, Optical Coherence Tomography (OCT) imaging of the tympanic membrane and middle ear can provide detailed volumetric images of the structure and function. These detailed images can form the basis for an approach for finding early signs of ear disease. Our hypothesis is that asymmetry between the ears could be used for early diagnosis. In order to test this, we need to understand the naturally occurring asymmetry in healthy volunteers. We have collected volumetric OCT images from 8 healthy subjects using a hand-held otoscopic OCT system. As part of a registration algorithm, we crop and down sample the data before finding the transformation matrix that registers the volumes. This matrix is then used to register the original volumes. Then the quantitative analysis of the symmetry between the left and right ears was applied through the similarity coefficient and overall, the left and right ears similarity of 8 healthy subjects has a mean of 0.7892, and a standard deviation of 0.0186. From a scientific perspective, this is the first quantitative measure of how symmetric the right and left ears are in humans. From a diagnostic perspective, this approach could provide a simple method to find early signs of ear disease.
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