Optical assessment of the in vivo tympanic membrane status using a handheld optical coherence tomography-based otoscope

Label-Free Optical Technologies for Middle-Ear Diseases

Medical applications of optical technology have increased tremendously in recent decades. Label-free techniques have the unique advantage of investigating biological samples in vivo without introducing exogenous agents. This is especially beneficial for a rapid clinical translation as it reduces the need for toxicity studies and regulatory approval for exogenous labels. Emerging applications have utilized label-free optical technology for screening, diagnosis, and surgical guidance. Advancements in detection technology and rapid improvements in artificial intelligence have expedited the clinical implementation of some optical technologies. Among numerous biomedical application areas, middle-ear disease is a unique space where label-free technology has great potential. The middle ear has a unique anatomical location that can be accessed through a dark channel, the external auditory canal; it can be sampled through a tympanic membrane of approximately 100 microns in thickness. The tympanic membrane is the only membrane in the body that is surrounded by air on both sides, under normal conditions. Despite these favorable characteristics, current examination modalities for middle-ear space utilize century-old technology such as white-light otoscopy. This paper reviews existing label-free imaging technologies and their current progress in visualizing middle-ear diseases. We discuss potential opportunities, barriers, and practical considerations when transitioning label-free technology to clinical applications.

Clinical practice guidelines for the diagnosis and management of otitis media with effusion (OME) in children in Japan - 2022 update

This is an update of the 2015 Guidelines developed by the Japan Otological Society and Oto-Rhino-Laryngeal Society of Japan defining otitis media with effusion (OME) in children (younger than 12 years old) and describing the disease rate, diagnosis, and method of examination. Recommended therapies that received consensus from the guideline committee were updated in consideration of current therapies used in Japan and based on available evidence.

METHOD

Regarding the treatment of OME in children, we developed Clinical Questions (CQs) and retrieved documents on each theme, including the definition, disease state, method of diagnosis, and medical treatment. In the previous guidelines, no retrieval expression was used to designate a period of time for literature retrieval. Conversely, a literature search of publications from March 2014 to May 2019 has been added to the JOS 2015 Guidelines. For publication of the CQs, we developed and assigned strengths to recommendations based on the collected evidence.

RESULTS

OME in children was classified into one group lacking the risk of developing chronic or intractable disease and another group at higher risk (e.g., children with Down syndrome, cleft palate), and recommendations for clinical management, including follow-up, is provided. Information regarding management of children with unilateral OME and intractable cases complicated by adhesive otitis media is also provided.

CONCLUSION

In clinical management of OME in children, the Japanese Clinical Practice Guidelines recommends management not only of complications of OME itself, such as effusion in the middle ear and pathologic changes in the tympanic membrane, but also pathologic changes in surrounding organs associated with infectious or inflammatory diseases.

Automated classification of otitis media with OCT: augmenting pediatric image datasets with gold-standard animal model data

Otitis media (OM) is an extremely common disease that affects children worldwide. Optical coherence tomography (OCT) has emerged as a noninvasive diagnostic tool for OM, which can detect the presence and quantify the properties of middle ear fluid and biofilms. Here, the use of OCT data from the chinchilla, the gold-standard OM model for the human disease, is used to supplement a human image database to produce diagnostically relevant conclusions in a machine learning model. Statistical analysis shows the datatypes are compatible, with a blended-species model reaching ∼95% accuracy and F1 score, maintaining performance while additional human data is collected.

In vivo functional imaging of the human middle ear with a hand-held optical coherence tomography device

We describe an optical coherence tomography and vibrometry system designed for portable hand-held usage in the otology clinic on awake patients. The system provides clinically relevant point-of-care morphological imaging with 14-44 µm resolution and functional vibratory measures with sub-nanometer sensitivity. We evaluated various new approaches for extracting functional information including a multi-tone stimulus, a continuous chirp stimulus, and alternating air and bone stimulus. We also explored the vibratory response over an area of the tympanic membrane (TM) and generated TM thickness maps. Our results suggest that the system can provide real-time in vivo imaging and vibrometry of the ear and could prove useful for investigating otologic pathology in the clinic setting.

Novel Radiologic Approaches for Cholesteatoma Detection: Implications for Endoscopic Ear Surgery

Technological advancement in computed tomography (CT) and MRI has improved cholesteatoma detection rates considerably in the past decade. Accurately predicting disease location and extension is essential for staging, planning, and preoperative counseling, in particular in the newer approach of endoscopic ear surgery. Improved sensitivity and specificity of these radiological methods may allow the surgeon to confidently monitor patients, therefore avoiding unnecessary surgery. This article outlines recent advances in CT and MRI technology and advantages and disadvantages of the newer techniques. Emphasis on improving the feedback loop between the radiologist and surgeon will increase the accuracy of these new technologies.

Optical coherence tomography: current and future clinical applications in otology

PURPOSE OF REVIEW

This article reviews literature on the use of optical coherence tomography (OCT) in otology and provides the reader with a timely update on its current clinical and research applications. The discussion focuses on the principles of OCT, the use of the technology for the diagnosis of middle ear disease and for the delineation of in-vivo cochlear microarchitecture and function.

RECENT FINDINGS

Recent advances in OCT include the measurement of structural and vibratory properties of the tympanic membrane, ossicles and inner ear in healthy and diseased states. Accurate, noninvasive diagnosis of middle ear disease, such as otosclerosis and acute otitis media using OCT, has been validated in clinical studies, whereas inner ear OCT imaging remains at the preclinical stage. The development of recent microscopic, otoscopic and endoscopic systems to address clinical and research problems is reviewed.

SUMMARY

OCT is a real-time, noninvasive, nonionizing, point-of-care imaging modality capable of imaging ear structures in vivo. Although current clinical systems are mainly focused on middle ear imaging, OCT has also been shown to have the ability to identify inner ear disease, an exciting possibility that will become increasingly relevant with the advent of targeted inner ear therapies.

A bench-top model of middle ear effusion diagnosed with optical tympanometry

OBJECTIVES

To assess the validity of a bench-top model of an optical tympanometry device to diagnose in vitro model of middle ear effusion (MEE).

METHODS AND MATERIALS

We illuminated an in vitro model of ear canal and tympanic membrane with broadband light and relayed remitted light to a spectrometer system. We then used our proprietary algorithm to extract spectral features that, together with our logistic regression classifiers, led us to calculate a set of simplified indices related to different middle ear states. Our model included a glass vial covered with a porcine submucosa (representing the tympanic membrane) and filled with air, water, or milk solution (representing different MEE), and a set of cover-glass slips filled with either blood (representing erythema) or cerumen. By interchanging fluid types and cover-glass slips, we made measurements on combinations corresponding to normal healthy ear and purulent or serous MEE.

RESULTS

Each simulated condition had a distinct spectral profile, which was then employed by our algorithm to discriminate clean and cerumen-covered purulent and serous MEE. Two logistic purulent and serous MEE classifiers correctly classified all in vitro middle ear states with 100% accuracy assessed by leave-one-out and k-fold cross validation.

CONCLUSIONS

This proof-of-concept in vitro study addressed an unmet need by introducing a device that easily and accurately can assess middle ear effusion. Future in vivo studies aimed at collecting data from clinical settings are warranted to further elucidate the validity of the technology in diagnosing pediatric acute otitis media.

Panel 1: Biotechnology, biomedical engineering and new models of otitis media

OBJECTIVE

To summarize recently published key articles on the topics of biomedical engineering, biotechnology and new models in relation to otitis media (OM).

DATA SOURCES

Electronic databases: PubMed, Ovid Medline, Cochrane Library and Clinical Evidence (BMJ Publishing).

REVIEW METHODS

Articles on biomedical engineering, biotechnology, material science, mechanical and animal models in OM published between May 2015 and May 2019 were identified and subjected to review. A total of 132 articles were ultimately included.

RESULTS

New imaging technologies for the tympanic membrane (TM) and the middle ear cavity are being developed to assess TM thickness, identify biofilms and differentiate types of middle ear effusions. Artificial intelligence (AI) has been applied to train software programs to diagnose OM with a high degree of certainty. Genetically modified mice models for OM have further investigated what predisposes some individuals to OM and consequent hearing loss. New vaccine candidates protecting against major otopathogens are being explored and developed, especially combined vaccines, targeting more than one pathogen. Transcutaneous vaccination against non-typeable Haemophilus influenzae has been successfully tried in a chinchilla model. In terms of treatment, novel technologies for trans-tympanic drug delivery are entering the clinical domain. Various growth factors and grafting materials aimed at improving healing of TM perforations show promising results in animal models.

CONCLUSION

New technologies and AI applications to improve the diagnosis of OM have shown promise in pre-clinical models and are gradually entering the clinical domain. So are novel vaccines and drug delivery approaches that may allow local treatment of OM.

IMPLICATIONS FOR PRACTICE

New diagnostic methods, potential vaccine candidates and the novel trans-tympanic drug delivery show promising results, but are not yet adapted to clinical use.

Otitis Media Middle Ear Effusion Identification and Characterization Using an Optical Coherence Tomography Otoscope

OBJECTIVE

To determine the feasibility of detecting and differentiating middle ear effusions (MEEs) using an optical coherence tomography (OCT) otoscope.

STUDY DESIGN

Cross-sectional study.

SETTING

US tertiary care children's hospital.

SUBJECTS AND METHODS

Seventy pediatric patients undergoing tympanostomy tube placement were preoperatively imaged using an OCT otoscope. A blinded reader quiz was conducted using 24 readers from 4 groups of tiered medical expertise. The primary outcome assessed was reader ability to detect presence/absence of MEE. A secondary outcome assessed was reader ability to differentiate serous vs nonserous MEE.

RESULTS

OCT image data sets were analyzed from 45 of 70 total subjects. Blinded reader analysis of an OCT data subset for detection of MEE resulted in 90.6% accuracy, 90.9% sensitivity, 90.2% specificity, and intra/interreader agreement of 92.9% and 87.1%, respectively. Differentiating MEE type, reader identification of nonserous MEE had 70.8% accuracy, 53.6% sensitivity, 80.1% specificity, and intra/interreader agreement of 82.9% and 75.1%, respectively. Multivariate analysis revealed that age was the strongest predictor of OCT quality. The mean age of subjects with quality OCT was 5.01 years (n = 45), compared to 2.54 years (n = 25) in the remaining subjects imaged (P = .0028). The ability to capture quality images improved over time, from 50% to 69.4% over the study period.

CONCLUSION

OCT otoscopy shows promise for facilitating accurate MEE detection. The imageability with the prototype device was affected by age, with older children being easier to image, similar to current ear diagnostic technologies.

[Overview of modern methods for the diagnosis of exudative otitis media]

Modern methods for diagnosis of exudative otitis media (EOM) have great potential, however, the problem of diagnosis of EOM is still relevant. The article describes the methods of modern diagnostics that are widely used in the daily practice of an otolaryngologist. The basic principles, advantages and disadvantages of generally accepted diagnostic methods for EOM are presented. The method of optical coherence tomography (OCT) is described as a method of studying biological tissues, which is used in many fields of medicine. Information is provided on the possibilities of OCT in the diagnosis of diseases of the ENT organs and, in particular, of the middle ear. The results of studies of the tympanic cavity structures in various inflammatory conditions, the possibilities of intrasurgery use of OCT, as well as the possibilities and perspectives of introducing OCT into the practice of an otorhinolaryngologist in the diagnosis of exudative otitis media are described.

Recovery from tympanic membrane perforation: Effects on membrane thickness, auditory thresholds, and middle ear transmission

Sounds delivered to the ear move the tympanic membrane (TM), which drives the middle-ear (ME) ossicles and transfers the acoustic energy to the cochlea. Perforations of the TM result in hearing loss because of less efficient sound conduction through the ME. The patterns of TM motions, and thus ME sound transmission, vary with frequency and depend on many factors, including the TM thickness. In this study, we measured TM thickness, auditory brainstem responses (ABR), and ME transmission immediately following a controlled pars tensa perforation and after 4 weeks of spontaneous recovery in a gerbil model. It is found that after recovery, the hearing thresholds showed a sloping pattern across frequencies: almost back to normal levels at frequencies between 2 and 8 kHz, sloping loss in the low (<2 kHz) and mid-frequency (8-30 kHz) range, and little restoration at frequencies above 30 kHz. This pattern was confirmed by the measured ME pressure gains. The thickness of the healed TM did not return to normal but was 2-3 times thicker over a significant portion of the membrane. The increased thickness was not limited to the perforated area but expanded into intact regions adjacent to the perforation, which led to an increased thickness in general. Combined, these results suggest that TM thickness is an important factor in determining its vibration patterns and efficiency to transfer sounds to the ossicles and thus influencing ME sound transmission, especially for high-frequency sounds. The results provided both structural and functional observations to explain the conductive hearing loss seen in patients with abnormal TMs, e.g., caused by otitis media, spontaneously healed post-perforation, or repaired via tympanoplasty in the clinic.

Clinical Utility of Intraoperative Tympanomastoidectomy Assessment Using a Surgical Microscope Integrated with an Optical Coherence Tomography

Significant technical and optical advances are required for intraoperative optical coherence tomography (OCT) to be utilized during otological surgeries. Integrating OCT with surgical microscopy makes it possible to evaluate soft tissue in real-time and at a high resolution. Herein, we describe an augmented-reality, intraoperative OCT/microscope system with an extended working distance of 280 mm, providing more space for surgical manipulation than conventional techniques. We initially performed ex vivo experiments to evaluate system performance. In addition, we validated the system by performing preliminary clinical assessments of tympanomastoidectomy outcomes in six patients with chronic otitis media. The system evaluated residual inflammation in the region-of-interest of the mastoid bone. Most importantly, the system intraoperatively revealed the connection between the graft and the remnant tympanic membrane. The extended working distance allows otological surgeons to evaluate the status of both the mastoid bone and tympanic membrane during manipulation, affording full intraoperative imaging.

Myringitis: An update

Myringitis can be acute or chronic. Though they commonly present with ear discharge with or without pain, the etiology and the management principles differ. Granular myringitis generally is an external ear pathology extending to tympanic membrane and present as painless otorrhea, whereas the bullous myringitis is commonly associated with acute inflammation of middle ear cleft and present with severe ear pain. This literature review discusses the clinical as well as the therapeutic aspects of these inflammatory conditions.