Estimating Brain Deformation During Surgery Using Finite Element Method: Optimization and Comparison of Two Linear Models

Abstract

This paper addresses estimation of brain deformation during craniotomy using finite element modeling. Two mechanical models are optimized and compared for this purpose: linear solid-mechanic model and linear elastic model. Both models assume the realistic finite deformation of the brain after opening the skull. In this study, we use pre-operative and intra-operative magnetic resonance images (MRI) of five patients undergoing brain tumor surgery. Anatomical landmarks are identified by an expert radiologist on MRI and used for the method development and comparison studies. We use tetrahedral finite element meshes and optimize model parameters by minimizing the mean distance between the predicted locations of the anatomical landmarks using the pre-operative images and their actual locations on the intra-operative images. Evaluation of the objective function using a second set of landmarks not used in the optimization process suggests that accuracy of the solid mechanic model is higher than that of the elastic model for our application. Visual inspection of the results confirms this conclusion. The proposed method along with the location information of the surface landmarks measured in the operating room and marked on the pre-operative images can be used to estimate the brain deformations without needing intra-operative images. In this case, since the parameters of the brain tissue are not the same for different patients, the proposed optimization process is crucial for obtaining accurate results.

An Optimised Linear Mechanical Model for Estimating Brain Shift Caused by Meningioma Tumours

“…It has been shown that such models provide numerical formulations that sufficiently describe brain tissue behaviour [3]. In addition, linear models are simpler to implement and run relatively fast.…”

“…Some such models are linear and assume that the stress and strain relationship is linear, while others assume a non-linear relationship. Linear models assume that the brain's response to stress and strain is similar to that of elastic or solid materials [3]. A study by Hamidian et al proved that the solid mechanical model is more reliable than the elastic model.…”

Surface Registration with Eigenvalues and Eigenvectors

“…Traditional landmark-based methods usually detect relevant corresponding points or curves in two shapes, i.e., landmarking is essential in many shape registration and mapping applications [4], [5], [6], [7], [8], [9]. There are two drawbacks in this type of methods.…”

Data-guide for brain deformation in surgery: comparison of linear and nonlinear models

“…In our previous study [ 8 ], we used the finite element method to develop and compare two linear models: mechanical and elastic [ 9 - 12 ] for image-guided neurosurgery. We showed that accurate computation of brain deformation due to craniotomy can be achieved by defining a load through prescribed displacements of the corresponding points in the pre- and intra-operative images.…”