Optical Coherence Tomography of the Middle Ear

Number: 0928

Policy

Aetna considers optical coherence tomography (OCT) for the assessment and management of the middle ear experimental and investigational because the effectiveness of this approach has not been established.

Background

Optical coherence tomography (OCT) is a non-invasive, non-contrast imaging technology which uses near-infrared light to produce high-resolution cross-sectional images. OCT was developed as a technique enabling high-resolution, real-time and in-situ imaging of tissue microstructure without the need for tissue excision and processing (Popescu, 2011). OCT technology is now emerging as a diagnostic tool for imaging the auditory system. Analogous to ultrasound by measuring the intensity of infrared light rather than acoustical waves, it is suggested that OCT could be a useful tool to see through the tympanic membrane into the middle ear without requiring surgical manipulation, and to help diagnose diseases associated with the tympanic membrane and middle ear (Cho et al., 2015; Pitris et al., 2001).

Monroy et al. (2017) conducted a prospective observational case series in which optical coherence tomography (OCT) tracking was used to observe 25 pediatric patients diagnosed with chronic or recurrent otitis media perioperatively. Patients were followed before and throughout their treatment. Following OCT imaging, patient records were observed for an additional 6 months in follow-up. At each time point (preop, intraop, postop), the tympanic membrane (at the light reflex region) and directly adjacent middle-ear cavity were observed in vivo with a handheld OCT probe and portable system. Imaging results were compared with clinical outcomes to correlate the clearance of symptoms in relation to changes in the image-based features of infection. OCT images of most all participants showed the presence of additional infection-related biofilm structures during their initial consultation visit and similarly for patients imaged intraoperatively before myringotomy. Patients with no recurrence of infectious symptoms had no additional structures visible in OCT images during the postoperative visit. OCT image findings suggest surgical intervention consisting of myringotomy and tympanostomy tube placement provides a means to clear the middle ear of infection-related components, including middle-ear fluid and biofilms. Furthermore, the authors concluded that OCT was demonstrated as a rapid diagnostic tool to prospectively monitor patients in both outpatient and surgical settings.

Park et al. (2017) conducted a prospective study to examine the tympanic membranes (TMs) of 120 patients with middle ear conditions using a handheld optical coherence tomography-based otoscope (860 nm central wave length, 15 μm axial resolution, 15 μm lateral resolution, and 7 mm scanning range using relay lens). Both OCT and oto-endoscope images were compared according to the clinical characteristics such as perforation, retraction, and postoperative healing process. The objective grade about the thickness of perforation margins and the accurate information about the extent of TM retraction that was not distinguishable by oto-endoscopic exam could be identified using this system. The postoperative healing process of TMs could be also followed using the OCT device. The authors concluded that their findings suggest that the handheld OCT device would be another useful application.

Cho et al. (2015) report on the application of optical coherence tomography (OCT) for the diagnosis and evaluation of otitis media (OM). They evaluated 39 patients who were diagnosed with OM via standard otoendoscopic examination and audiological tests between July and October 2012. Six volunteers with normal tympanic membrane (TM) on otoendoscopy were also included, with OCT images used as a control. Of the 39 patients, OCT images were acquired from 16 patients (41.0%). The most common cause of failure to acquire an image was a narrow or curved external auditory canal (n=5). Other causes were the presence of obstacles, such as profuse otorrhea (n=3), cholesteatoma material (n=4), and cerumen (n=7), and poor compliance (n=4). OCT could not be obtained for the three patients with chronic OM with cholesteatomas. Despite the benefits such as noninvasiveness, lack of radiation, high resolution and ability to use outpatient, the authors report some limitations, such as, difficulty securing a light pathway for the OCT device, and the diagnostic efficiency of otoendoscopy. The authors concluded that their evaluation suggests that a handheld OCT otoscope can be applied clinically to otology, and that OCT has the potential to facilitate diagnosis of OM; however, further clinical trials are necessary.

MacDougall et al. (2015) state that optical coherence tomography (OCT) for imaging the middle ear can present some challenges for real-time clinical use. Although OCT is noninvasive, the challenges included 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. (Abstract only)

Nguyen et al. (2013) investigated the acoustic effects of bacterial biofilms, confirmed using optical coherence tomography (OCT), in adult ears. Biofilms have been linked to chronic otitis media (OM) and OM with effusion in the middle ear. Non-invasive OCT images were collected to visualize the 2D cross-sectional structure of the middle ear, verifying the presence of a biofilm behind the TM of 5 ears. Wideband measurements of acoustic reflectance and impedance (0.2 to 6 [kHz]) were used to study the acoustic properties of ears with confirmed bacterial biofilms. Compared to known acoustic properties of normal middle ears, each of the ears with a bacterial biofilm had an elevated power reflectance in the 1 to 3 [kHz] range, corresponding to an abnormally small resistance. The authors note that their preliminary study indicates that acoustic reflectance and impedance measurements may have utility for assessment of the presence and acoustic impact of biofilms in the middle ear; however, future study of a wide range of OM-related conditions, with definitive biofilm and non-biofilm classifications, is needed.

UpToDate reviews on “Evaluation and management of middle ear trauma” (Evans and Handler, 2017), “Acute otitis media in adults” (Limb et al., 2017), “Acute otitis media in children: Diagnosis” (Wald, 2017), and “Eustachian tube dysfunction” (Poe and Hanna, 2016) do not mention use of optical coherence tomography for diagnosis or management.

The above policy is based on the following references: