Development and Validation of a Göttingen Miniature Pig Brain Finite Element Model

The Center for Disease Control and Prevention reports that there are approximately 1.4 million emergency department visits, hospitalizations, or deaths per year in the USA due to traumatic brain injuries (TBI) [1]. In order to lessen the severity or prevent TBIs, accurate dummy models, simulations, and injury risk metrics must be used. Ideally, these models and metrics would be designed with the use of human data. However, available human data is sparse, so animal study data must be applied to the human brain. Animal data must be scaled before it can be applied, and current scaling methods are very simplified. The objective of our study was to develop a finite element (FE) model of a Göttingen mini-pig to allow study of the tissue level response under impact loading. A hexahedral FE model of a miniature pig brain was created from MRI images. The cerebrum, cerebellum, corpus callosum, midbrain, brainstem, and ventricles were modeled and assigned properties as a Kelvin-Maxwell viscoelastic material. To validate the model, tests were conducted using mini-pigs in an injury device that subjected the pig brain to both linear and angular motion. These pigs are commonly used for brain testing because the brains are well developed with folds and the material properties are similar to human brain. The pigs’ brains were embedded with neutral density radio-opaque markers to track the motion of the brain relative to the skull with a biplanar X-ray system. The impact was then simulated, and the motion of nodes closest to the marker locations was recorded and used to optimize material parameters and the skull-brain interface. The injuries were defined at a tissue level with damage measures such as cumulative strain damage measure (CSDM). In future the animal FE model could be used with a human FE model to determine an accurate animal-to-human transfer function.