Clinical optical coherence tomography of the middle ear

Conductive hearing loss affects 4% of adults and 1.5M Canadians. It is usually caused by a fixation or discontinuity of the structures behind the eardrum that carry sound from the eardrum to the cochlea. Ear surgeons would like to be able to image these structures in their clinics to help them make an informed decision about whether to proceed to ear surgery, but the options available to them are lacking. Using optical microscopy, they can image the eardrum but cannot see through it. The whole ear can be imaged using computed tomography (CT), but this exposes patients to radiation, and has trouble seeing soft tissue. We have developed a new imaging technology for the middle ear, optical coherence tomography (OCT), that allows us to both see ear structures through the eardrum and measure their vibration in response to sound. This helps doctors identify sites of fixation or discontinuity and understand what is wrong in a diseased ear. We have made a reliable, hand-held, easy-to-use, real-time clinical OCT imaging system and have shown that the images and vibration information it provides can diagnose one of the most common middle ear diseases, otosclerosis, better than competing technologies. We now want to quantify how effective our OCT system is at distinguishing a range of different middle ear diseases and determine how to best use the information from the system to form a diagnosis. We will simulate common middle ear diseases in human cadaver ears, image them with our OCT system and measure the vibration of various structures in response to sound. Using this data, we will determine the best way to combine the information to form a diagnosis. We will then transfer that approach to the clinic and test our system on the ears of patients with middle ear disease. In patients for whom we can obtain a confident diagnosis (e.g. through surgery or CT), we will be able to verify whether our noninvasive OCT measurement correctly predicts the diagnosis.