Realistic 3D computer model of the gerbil middle ear, featuring accurate morphology of bone and soft tissue structures

TL;DR

This paper presents a high-resolution, realistic 3D model of the gerbil middle ear combining micro-CT and OPFOS imaging techniques, enhancing the morphological accuracy for finite element modeling.

Contribution

It introduces a novel combination of  CT and OPFOS data for detailed, non-destructive 3D modeling of both bone and soft tissue structures in the gerbil middle ear.

Findings

Merged high-resolution models of bone and soft tissue structures.

Model is directly usable in finite element analysis.

Data is freely available for research use.

Abstract

In order to improve realism in middle ear (ME) finite element modeling (FEM), comprehensive and precise morphological data are needed. To date, micro-scale X-ray computed tomography (\mu CT) recordings have been used as geometric input data for FEM models of the ME ossicles. Previously, attempts were made to obtain this data on ME soft tissue structures as well. However, due to low X-ray absorption of soft tissue, quality of these images is limited. Another popular approach is using histological sections as data for 3D models, delivering high in-plane resolution for the sections, but the technique is destructive in nature and registration of the sections is difficult. We combine data from high-resolution \mu CT recordings with data from high-resolution orthogonal-plane fluorescence optical-sectioning microscopy (OPFOS), both obtained on the same gerbil specimen. State-of-the-art \mu CT delivers high-resolution data on the three-dimensional shape of ossicles and other ME bony structures, while the OPFOS setup generates data of unprecedented quality both on bone and soft tissue ME structures. Each of these techniques is tomographic and non-destructive, and delivers sets of automatically aligned virtual sections. The datasets coming from different techniques need to be registered with respect to each other. By combining both datasets, we obtain a complete high-resolution morphological model of all functional components in the gerbil ME. The resulting three-dimensional model can be readily imported in FEM software and is made freely available to the research community. In this paper, we discuss the methods used, present the resulting merged model and discuss morphological properties of the soft tissue structures, such as muscles and ligaments.