[Non-contact optical coherence tomography - an effective method for visualizing the exudate of the middle ear]

INTRODUCTION

Otitis media with effusion (OME) accounts for 15-17% of the total number of recorded diseases of the middle ear. Surgical methods have become much more common. One of the factors affecting the tactics and effectiveness of treatment OME is the degree of viscosity of the effusion. Modern diagnostic methods do not allow to reliably identify cases of OME with high effusion viscosity.

OBJECTIVE

To study the possibilities of optical coherence tomography (OCT) in the diagnosis of OME and a non-invasive study of effusion viscosity.

MATERIAL AND METHODS

An analysis of the results of the examination of 29 patients who underwent surgical treatment for OME - tympanostomy. A control group of 30 patients without middle ear pathology. The study used a spectral OCT with a non-contact probe designed specifically for studies of the structural middle ear. Quantitative analysis of the results using open source ImageJ. Objectification of the degree of viscosity of the effusion was carried out by means of viscometry. A comparative analysis of the intensity of the optical signal in the external auditory canal (EAC) and in the tympanic cavity (TC) was performed, as well as a comparison of the signal from viscous and fluid effusion.

RESULTS

In all patients with OME, during the OCT study, an optical signal with a higher intensity was recorded in TC than in the EAC. In all cases, in the control group in the TC, an optical signal was recorded that was identical in intensity with the signal in the EAC. When measuring the degree of viscosity of the effusion, 17 cases of OME were characterized as effusion of a low degree of viscosity, 12 cases - effusion of extreme viscosity. When comparing the average intensity of the optical signal of the OCT images of viscous and liquid effusion, a statistically significant difference was revealed, p<0.001.

DISCUSSION

OCT makes it possible to detect light scattering from large scatterers - cell structures characteristic of low viscosity effusion. In addition, OCT allows you to register an optical signal from small scatterers - high molecular weight structures that are present in large quantities in viscous effusion. A correlation was found between the intensity of the optical signal in the TC and the degree of viscosity of the middle ear effusion.

CONCLUSIONS

Based on OCT data, it is possible to determine the indications for surgical treatment of OME by detecting viscous exudate.

[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.

Optical coherence tomography for observation of the olfactory epithelium in mice

OBJECTIVE

Optical coherence tomography (OCT) is an imaging tool that exploits the coherence of infrared light and is clinically utilized in the field of ophthalmology and dermatology. This study aimed to examine the feasibility of using OCT for diagnosing degeneration and regeneration of the olfactory epithelium in mice.

METHODS

The olfactory and respiratory epithelia in excised nasal septa of adult mice were observed using OCT. Subsequently, histological assessments were performed with hematoxylin and eosin (H-E) staining. The thicknesses of the olfactory or respiratory epithelia were measured in both OCT images and H-E-stained paraffin sections. The ability of OCT to distinguish olfactory epithelia from respiratory epithelia in normal mice was compared with that of H-E staining. The feasibility of using OCT assessments for detecting changes in the thickness of olfactory epithelia was tested in a mouse model of the degeneration and regeneration of olfactory epithelia.

RESULTS

OCT allowed visualization of the gross morphology of the olfactory and respiratory epithelium in normal mice, although it was limited in terms of visualizing cellular components. OCT-based measurements of epithelial thickness helped to distinguish olfactory epithelia from respiratory epithelia. Similar to H-E staining, OCT also clarified changes in the olfactory epithelium thickness after methimazole application.

CONCLUSIONS

These findings indicate the utility of OCT for assessment of olfactory epithelial thickness and its potential for clinical evaluation of human olfactory epithelia.

Optical Coherence Tomography of the Tympanic Membrane and Middle Ear: A Review

Objective To evaluate the recent developments in optical coherence tomography (OCT) for tympanic membrane (TM) and middle ear (ME) imaging and to identify what further development is required for the technology to be integrated into common clinical use. Data Sources PubMed, Embase, Google Scholar, Scopus, and Web of Science. Review Methods A comprehensive literature search was performed for English language articles published from January 1966 to January 2018 with the keywords "tympanic membrane or middle ear,""optical coherence tomography," and "imaging." Conclusion Conventional imaging techniques cannot adequately resolve the microscale features of TM and ME, sometimes necessitating diagnostic exploratory surgery in challenging otologic pathology. As a high-resolution noninvasive imaging technique, OCT offers promise as a diagnostic aid for otologic conditions, such as otitis media, cholesteatoma, and conductive hearing loss. Using OCT vibrometry to image the nanoscale vibrations of the TM and ME as they conduct acoustic waves may detect the location of ossicular chain dysfunction and differentiate between stapes fixation and incus-stapes discontinuity. The capacity of OCT to image depth and thickness at high resolution allows 3-dimensional volumetric reconstruction of the ME and has potential use for reconstructive tympanoplasty planning and the follow-up of ossicular prostheses. Implications for Practice To achieve common clinical use beyond these initial discoveries, future in vivo imaging devices must feature low-cost probe or endoscopic designs and faster imaging speeds and demonstrate superior diagnostic utility to computed tomography and magnetic resonance imaging. While such technology has been available for OCT, its translation requires focused development through a close collaboration between engineers and clinicians.

Endoscopic optical coherence tomography: technologies and clinical applications [Invited]

In this paper, we review the current state of technology development and clinical applications of endoscopic optical coherence tomography (OCT). Key design and engineering considerations are discussed for most OCT endoscopes, including side-viewing and forward-viewing probes, along with different scanning mechanisms (proximal-scanning versus distal-scanning). Multi-modal endoscopes that integrate OCT with other imaging modalities are also discussed. The review of clinical applications of endoscopic OCT focuses heavily on diagnosis of diseases and guidance of interventions. Representative applications in several organ systems are presented, such as in the cardiovascular, digestive, respiratory, and reproductive systems. A brief outlook of the field of endoscopic OCT is also discussed.