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

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.

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

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.

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.

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.

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