We present the design, implementation and validation of a swept-source optical coherence tomography (OCT) system for real-time imaging of the human middle ear in live patients. Our system consists of a highly phase-stable Vernier-tuned distributed Bragg-reflector laser along with a real-time processing engine implemented on a graphics processing unit. We use the system to demonstrate, for the first time in live subjects, real-time Doppler measurements of middle ear vibration in response to sound, video rate 2D B-mode imaging of the middle ear and 3D volumetric B-mode imaging. All measurements were performed non-invasively through the intact tympanic membrane demonstrating that the technology is readily translatable to the clinic.

Noninvasive middle ear imaging using optical coherence tomography (OCT) presents some unique challenges for real-time, clinical use in humans. We present results from a two-dimensional/three-dimensional OCT system built to assess the imaging requirements of clinical middle ear imaging, and the technical challenges associated with them. These include the need to work at a low numerical aperture, the deleterious effects of transtympanic imaging on image quality at the ossicles, sensitivity requirements for clinical fidelity of images at real-time rates, and the high dynamic-range requirements of the ear. We validated the system by imaging cadaveric specimens with simulated disorders to show the clinical applicability of the images. We also provide additional insight into the likely role of OCT in clinical otology.

Hypothesis: Ears with otosclerotic stapes fixation will exhibit lower-than-normal levels of ossicular mobility as measured by Optical Coherence Tomography Doppler Vibrometry (OCT-DV). Background: OCT-DV measures the vibration of middle ear structures in response to sound non-invasively through the intact tympanic membrane. This allows, in particular, direct measurement of the vibration at the lenticular process of the incus which is expected to be lower in patients with otosclerotic stapes fixation. Methods: OCT-DV was performed on ears presumptively diagnosed with otosclerosis (n = 13) and a group of normal control ears (n = 42). Displacement was measured at the umbo and the lenticular process of the incus in response to 500 and 1000 Hz stimulus tones at 100 dBSPL. Main Outcome Measure: The ability to discriminate between groups was assessed using receiver operator characteristic analysis, with the main outcome measures being the area-under-curve (AUC) and the sensitivity and specificity. Results: For the best condition tested (500 Hz at the incus), the AUC was 0.998 and discriminated the otosclerotic from normal ears with a sensitivity/specificity of 1.00/0.98. One anomalous patient with surgically confirmed stapes fixation exhibited hypermobility at the umbo, possibly due to a partial ossicular discontinuity. Despite the high umbo mobility, this patient's stapes fixation was correctly discriminated based on the measured incus vibration levels. Conclusions: OCT-DV is a promising tool for preoperatively assessing ossicular mobility non-invasively in the clinic. Our results suggest OCT-DV may also be useful in discriminating other ossicular pathologies that result in conductive hearing loss.

Various U.S. laws, such as the Clean Air Act and the Food Quality Protection Act, require additional protections for susceptible subpopulations who face greater environmental health risks. The main ethical rationale for providing these protections is to ensure that environmental health risks are distributed fairly. In this article, we (1) consider how several influential theories of justice deal with issues related to the distribution of environmental health risks; (2) show that these theories often fail to provide specific guidance concerning policy choices; and (3) argue that an approach to public decision making known as accountability for reasonableness can complement theories of justice in establishing acceptable environmental health risks for the general population and susceptible subpopulations. Since accountability for reasonableness focuses on the fairness of the decision-making process, not the outcome, it does not guarantee that susceptible subpopulations will receive a maximum level of protection, regardless of costs or other morally relevant considerations.

ObjectiveThis study aimed to evaluate the ability of transtympanic middle ear optical coherence tomography (ME-OCT) to assess placement of cochlear implants (CIs) in situ.PatientA 72-year-old man with bilateral progressive heredodegenerative sensorineural hearing loss due to work-related noise exposure received a CI with a slim modiolar electrode for his right ear 3 months before his scheduled checkup.InterventionA custom-built swept source ME-OCT system (λo = 1550 nm, ∆λ = 40 nm) designed for transtympanic middle ear imaging was used to capture a series of two- and three-dimensional images of the patient's CI in situ. Separately, transtympanic OCT two-dimensional video imaging and three-dimensional imaging were used to visualize insertion and removal of a CI with a slim modiolar electrode in a human cadaveric temporal bone through a posterior tympanotomy.Main Outcome MeasureImages and video were analyzed qualitatively to determine the visibility of implant features under ME-OCT imaging and quantitatively to determine insertion depth of the CI.ResultsAfter implantation, the CI electrode could be readily visualized in the round window niche under transtympanic ME-OCT in both the patient and the temporal bone. In both cases, characteristic design features of the slim modiolar electrode allowed us to quantify the insertion depth from our images.ConclusionsME-OCT could potentially be used in a clinic as a noninvasive, nonionizing means to confirm implant placement. This study shows that features of the CI electrode visible under ME-OCT can be used to quantify insertion depth in the postoperative ear.