METHOD FOR ASSESSING INTRANASAL AERODYNAMICS Russian patent published in 2023 - IPC A61B6/03 A61B5/08 

FIELD: medicine, otorhinolaryngology.

SUBSTANCE: anterior active rhinomanometry (PARM) in the right and left nasal passages separately is performed. Computed tomography (CT) is performed, during which images of the paranasal sinuses are obtained in the form of 2D images. Then 2D images are reconstructed in sagittal and coronal projections and a file is obtained with an image of the paranasal sinuses in the following three projections: coronal, sagittal and axial. After that, the resulting file is written to a DVD disc in the form of a DICOM file which is then converted first into a 3D image of the patient's head, then into a file with STL resolution, which is converted into a solid geometric three-dimensional 3D model of the upper respiratory tract. Then a 3D model of the movement of air flows in each nasal passage is built in the form of a graphic image in the coordinate system. In this case, the intensity of the air flow in each nasal passage is determined by the degree of coloring of its image from saturated blue, corresponding to a speed of 0 m/s, to red, corresponding to a speed of 5.0 m/s. When performing PARM, nasal flow velocity is measured during inhalation at a pressure of 150 Pa, and the DICOM file is converted from a sequence of 2D images into 3D images of the patient's head using the Invesalius program. An STL file containing a 3D image of the patient's head is converted into a 3D model of the upper respiratory tract using the Ansys Space С lame 2019 R3 program. Moreover, the resulting 3D model covers the nasal cavity, paranasal sinuses, nasopharynx, larynx and upper trachea. The construction of a 3D model of the movement of air flows is carried out in the inhalation mode in the Ansys Fluint 2019 R3 program. In this case, the values of the air flow velocity obtained during the PRM are used as boundary conditions. After that, coronal sections of a 3D model of the movement of air flows are made to visualize the color intensity of the air flow on each section of the resulting projection. It is additionally evaluated in the Ansys CDF-post 2019 R3 program according to the following criteria: ventilation symmetry of the right and left nasal passages, comparison of the identified zones with the highest and lowest ventilation in each nasal passage with the values of physiological norms, calculation of nasal flow velocity at a specific point. After that, based on the results of the assessment, either conservative or surgical treatment is prescribed.

EFFECT: method makes it possible to increase the efficiency of examining patients with difficulty in nasal breathing by identifying areas in the nasal cavity with impaired intranasal aerodynamics by building a personal 3D model of air flow in each nasal passage.

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