Finite-Element Modelling Based on Optical Coherence Tomography and Corresponding X-ray MicroCT Data for Three Human Middle Ears.

Abstract

Optical coherence tomography (OCT) is an emerging imaging modality which is non-invasive, can be employed in vivo, and can record both anatomy and vibrations. The purpose here is to explore the application of finite-element (FE) modelling to OCT data. We recorded vibrations for three human cadaver middle ears using OCT. We also have X-ray microCT images from the same ears. Three FE models were built based on geometries obtained from the microCT images. The material properties and boundary conditions of the models were obtained from previously reported studies. Tympanic-membrane (TM) vibration patterns were computed for the three models and compared with the patterns measured using OCT. Frequency responses were also computed for all three models for several locations in the middle ear and compared with the OCT displacements and with the literature. The three models were compared with each other in terms of geometry and function. Parameter sensitivity analyses were done and the results were compared among the models and with the literature. The simulated TM displacement patterns are qualitatively similar to the OCT results. The simulated displacements are closer to the OCT results for 500Hz and 1kHz but the differences are greater at 2kHz. This study provides an initial look at the combined use of OCT measurements and FE modelling based on subject-specific anatomy. The geometries and parameters of the existing FE models could be modified for individual patients in the future to help identify abnormalities in the middle ear.