3D finite element model of posterior membranous labyrinth from in vivo MRI of human temporal bone, including sensory zones

Objective: The aim of this work is to create a three-dimensional (3D) finite element model (FEM) of the human posterior membranous labyrinth, based on in vivo inner ear magnetic resonance imaging (MRI). Study design and setting: We used T2 weighted gradient-echo 3T MRI of a human inner ear. Images were acquired in vivo, from a patient presenting a vestibular schwannoma with a preserved labyrinthine geometry. Indeed, in this context, the elevation of the perilymphatic protides level secondary to the obstructive vestibular schwannoma enables a differentiation between the endolymph (which remains hyperintense on T2 weighted images) and the perilymph (hypointense on T2 weighted gradient echo images). Results: A 3D reconstruction of the posterior membranous labyrinth was performed through manual segmentation of the endolymphatic and sensory spaces. A mesh of the labyrinth was realized, first of its outer surface and then of its interior volume. The different structures of the labyrinth are included through a compartmentalization of the mesh. Sensory zones are precisely defined, based on a radio-histological correlation study. The resulting mesh of the model included 124,701 elements. Conclusion: Dimensions are in agreement with those in the literature, which is in favor of the validity of the model geometry. This model also has a pedagogical interest and can be useful for the clinical reflexion in cases of atypical benign paroxysmal positional vertigos (BPPV). It can also serve as a base for mechanical studies of vestibular physiology.