Pneumatic low-coherence interferometry otoscope to quantify tympanic membrane mobility and middle ear pressure

Imaging of Alternobaric Facial Palsy: An Etiologic Hypothesis

OBJECTIVE

To report a case of alternobaric facial palsy (AFP) with a hyperpneumatized temporal bone and to review the relevant literature in order to propose a new facet of AFP pathogenesis.

METHODS

A patient with a hyperpneumatized temporal bone was found to have recurrent episodes of facial palsy associated with air travel. Systematic review of PubMed, Cochrane Library, and Embase characterized all articles related to transient facial palsy associated with altitude changes or diving with a focus on demographics and imaging findings.

RESULTS

A 25 year-old male was referred for recurrent facial palsy associated with commercial air travel. Imaging demonstrated a hyperpneumatized and well-aerated temporal bone. Total air cell volume was calculated to be 8.59 cc on the affected side. A systematic review of the literature identified 49 cases of AFP. Mean age was 34 years old and 80% were male. Twelve cases had imaging of the temporal bone for evaluation, of which 85% demonstrated at least 1 area of hyperpneumatization. Hyperpneumatization was most frequently encountered in the mastoid, zygomatic root, and inferior petrous apex.

CONCLUSION

Hyperpneumatization of the temporal bone is critical to AFP etiology as it predicts higher middle ear pressure, if atmospheric pressure changes cannot be equilibrated, via reduced efficacy of normal tympanic membrane pressure buffering. This hypothesis helps to better account for the rarity of the condition and male preponderance.

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.

Multimodal Handheld Probe for Characterizing Otitis Media - Integrating Raman Spectroscopy and Optical Coherence Tomography

Otitis media (OM) is a common disease of the middle ear, affecting 80% of children before the age of three. The otoscope, a simple illuminated magnifier, is the standard clinical diagnostic tool to observe the middle ear. However, it has limited contrast to detect signs of infection, such as clearly identifying and characterizing middle ear fluid or biofilms that accumulate within the middle ear. Likewise, invasive sampling of every subject is not clinically indicated nor practical. Thus, collecting accurate noninvasive diagnostic factors is vital for clinicians to deliver a precise diagnosis and effective treatment regimen. To address this need, a combined benchtop Raman spectroscopy (RS) and optical coherence tomography (OCT) system was developed. Together, RS-OCT can non-invasively interrogate the structural and biochemical signatures of the middle ear under normal and infected conditions.In this paper, in vivo RS scans from pediatric clinical human subjects presenting with OM were evaluated in parallel with RS-OCT data of physiologically relevant in vitro ear models. Component-level characterization of a healthy tympanic membrane and malleus bone, as well as OM-related middle ear fluid, identified the optimal position within the ear for RS-OCT data collection. To address the design challenges in developing a system specific to clinical use, a prototype non-contact multimodal handheld probe was built and successfully tested in vitro. Design criteria have been developed to successfully address imaging constraints imposed by physiological characteristics of the ear and optical safety limits. Here, we present the pathway for translation of RS-OCT for non-invasive detection of OM.

New Approaches and Technologies to Improve Accuracy of Acute Otitis Media Diagnosis

Several studies have shown that in recent years incidence of acute otitis media (AOM) has declined worldwide. However, related medical, social, and economic problems for patients, their families, and society remain very high. Better knowledge of potential risk factors for AOM development and more effective preventive interventions, particularly in AOM-prone children, can further reduce disease incidence. However, a more accurate AOM diagnosis seems essential to achieve this goal. Diagnostic uncertainty is common, and to avoid risks related to a disease caused mainly by bacteria, several children without AOM are treated with antibiotics and followed as true AOM cases. The main objective of this manuscript is to discuss the most common difficulties that presently limit accurate AOM diagnosis and the new approaches and technologies that have been proposed to improve disease detection. We showed that misdiagnosis can be dangerous or lead to relevant therapeutic mistakes. The need to improve AOM diagnosis has allowed the identification of a long list of technologies to visualize and evaluate the tympanic membrane and to assess middle-ear effusion. Most of the new instruments, including light field otoscopy, optical coherence tomography, low-coherence interferometry, and Raman spectroscopy, are far from being introduced in clinical practice. Video-otoscopy can be effective, especially when it is used in association with telemedicine, parents' cooperation, and artificial intelligence. Introduction of otologic telemedicine and use of artificial intelligence among pediatricians and ENT specialists must be strongly promoted in order to reduce mistakes in AOM diagnosis.

Assessing the Effect of Middle Ear Effusions on Wideband Acoustic Immittance Using Optical Coherence Tomography

Wideband acoustic immittance (WAI) noninvasively assesses middle ear function by measuring the sound conduction over a range of audible frequencies. Although several studies have shown the potential of WAI for detecting the presence of middle ear effusions (MEEs), determining the effects of MEE type and amount on WAI in vivo has been challenging due to the anatomical location of middle ear cavity. The purpose of this study is to correlate WAI measurements with physical characteristics of the middle ear and MEEs determined by optical coherence tomography (OCT), a noninvasive optical imaging technique.

Shortwave infrared otoscopy for diagnosis of middle ear effusions: a machine-learning-based approach

Otitis media, a common disease marked by the presence of fluid within the middle ear space, imparts a significant global health and economic burden. Identifying an effusion through the tympanic membrane is critical to diagnostic success but remains challenging due to the inherent limitations of visible light otoscopy and user interpretation. Here we describe a powerful diagnostic approach to otitis media utilizing advancements in otoscopy and machine learning. We developed an otoscope that visualizes middle ear structures and fluid in the shortwave infrared region, holding several advantages over traditional approaches. Images were captured in vivo and then processed by a novel machine learning based algorithm. The model predicts the presence of effusions with greater accuracy than current techniques, offering specificity and sensitivity over 90%. This platform has the potential to reduce costs and resources associated with otitis media, especially as improvements are made in shortwave imaging and machine learning.

In vivo dynamic characterization of the human tympanic membrane using pneumatic optical coherence tomography

Decreased mobility of the human eardrum, the tympanic membrane (TM), is an essential indicator of a prevalent middle ear infection. The current diagnostic method to assess TM mobility is via pneumatic otoscopy, which provides subjective and qualitative information of subtle motion. In this study, a handheld spectral-domain pneumatic optical coherence tomography system was developed to simultaneously measure the displacement of the TM, air pressure inputs applied to a sealed ear canal, and to perform digital pneumatic otoscopy. A novel approach based on quantitative parameters is presented to characterize spatial and temporal variations of the dynamic TM motion. Furthermore, the TM motions of normal middle ears are compared with those of ears with middle ear infections. The capability of noninvasively measuring the rapid motion of the TM is beneficial to understand the complex dynamics of the human TM, and can ultimately lead to improved diagnosis and management of middle ear infections.

Longitudinal optical coherence tomography to visualize the in vivo response of middle ear biofilms to antibiotic therapy

Studying the impact of antibiotic treatment on otitis media (OM), the leading cause of primary care office visits during childhood, is critical to develop appropriate treatment strategies. Tracking dynamic middle ear conditions during antibiotic treatment is not readily applicable in patients, due to the limited diagnostic techniques available to detect the smaller amount and variation of middle ear effusion (MEE) and middle ear bacterial biofilm, responsible for chronic and recurrent OM. To overcome these challenges, a handheld optical coherence tomography (OCT) system has been developed to monitor in vivo response of biofilms and MEEs in the OM-induced chinchilla model, the standard model for human OM. As a result, the formation of MEE as well as biofilm adherent to the tympanic membrane (TM) was longitudinally assessed as OM developed. Various types of MEEs and biofilms in the chinchilla model were identified, which showed comparable features as those in humans. Furthermore, the effect of antibiotics on the biofilm as well as the amount and type of MEEs was investigated with low-dose and high-dose treatment (ceftriaxone). The capability of OCT to non-invasively track and examine middle ear conditions is highly beneficial for therapeutic OM studies and will lead to improved management of OM in patients.

Phase-based Eulerian motion magnification reveals eardrum mobility from pneumatic otoscopy without sealing the ear canal

Pneumatic otoscopy is the recommended diagnostic method for middle ear infections. Physicians use a pneumatic otoscope to assess the position of the eardrum (bulging or retraction) as well as the eardrum mobility while an insufflation bulb is squeezed to generate air pressure changes in a sealed ear canal. While pneumatic otoscopy provides increased sensitivity and specificity by detecting decreased eardrum mobility, there exist many challenges to correctly perform and interpret results. For example, the ear canal must be sealed using a specialized ear speculum to deliver sufficiently large pressure changes that can induce visible movements of an eardrum. To overcome this challenge, video motion magnification is proposed to amplify pneumatic-induced motions of the eardrum without sealing of the ear canal. Pneumatic otoscopy is performed on adult subjects using a smartphone camera with an otoscope attachment at 60 frames per second, with pressure inputs at 5 Hz. Phase-based Eulerian motion magnification is applied to magnify spatiotemporal dependent motions in the video. As a result, the motion magnification of unsealed pneumatic otoscopy reveals comparable eardrum motions as in standard pneumatic otoscopy with a sealed ear canal. Furthermore, the estimated motions (in pixels) are quantified to examine the spatial and the temporal variations of the eardrum motions. The motion magnification may avoid the need for sealing the ear canal as well as decrease patient discomfort in pneumatic otoscopy, improving the capability and the usability as a point-of-care diagnostic tool in primary care and otology.

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.

Automated classification platform for the identification of otitis media using optical coherence tomography

The diagnosis and treatment of otitis media (OM), a common childhood infection, is a significant burden on the healthcare system. Diagnosis relies on observer experience via otoscopy, although for non-specialists or inexperienced users, accurate diagnosis can be difficult. In past studies, optical coherence tomography (OCT) has been used to quantitatively characterize disease states of OM, although with the involvement of experts to interpret and correlate image-based indicators of infection with clinical information. In this paper, a flexible and comprehensive framework is presented that automatically extracts features from OCT images, classifies data, and presents clinically relevant results in a user-friendly platform suitable for point-of-care and primary care settings. This framework was used to test the discrimination between OCT images of normal controls, ears with biofilms, and ears with biofilms and middle ear fluid (effusion). Predicted future performance of this classification platform returned promising results (90%+ accuracy) in various initial tests. With integration into patient healthcare workflow, users of all levels of medical experience may be able to collect OCT data and accurately identify the presence of middle ear fluid and/or biofilms.

Economical and compact briefcase spectral-domain optical coherence tomography system for primary care and point-of-care applications

Development of low-cost and portable optical coherence tomography (OCT) systems is of global interest in the OCT research community. Such systems enable utility broadly throughout a clinical facility, or in remote areas that often lack clinical infrastructure. We report the development and validation of a low-cost, portable briefcase spectral-domain optical coherence tomography (SD-OCT) system for point-of-care diagnostics in primary care centers and/or in remote settings. The self-contained briefcase OCT contains all associated optical hardware, including light source, spectrometer, hand-held probe, and a laptop. Additionally, this system utilizes unique real-time mosaicking of surface video images that are synchronized with rapid A-scan acquisition to eliminate the need for lateral scanning hardware, and enable the construction of cross-sectional B-mode images over extended lateral distances. The entire briefcase system weighs 9 kg and costs ∼USD$8000 using off-the-shelf components. System performance was validated by acquiring images of in vivo human skin on the fingertip, palm, and nail fold. The efficiency, portability, and low-cost enable accessibility and utility in primary care centers and low-resource settings.