title: Regional mechanical properties of human brain tissue for computational models of traumatic brain injury.
abstract: To determine viscoelastic shear moduli, stress relaxation indentation tests were performed on samples of human brain tissue resected in the course of epilepsy surgery. Through the use of a 500µm diameter indenter, regional mechanical properties were measured in cortical grey and white matter and subregions of the hippocampus. All regions were highly viscoelastic. Cortical grey matter was significantly more compliant than the white matter or hippocampus which were similar in modulus. Although shear modulus was not correlated with the age of the donor, cortex from male donors was significantly stiffer than from female donors. The presented material properties will help to populate finite element models of the brain as they become more anatomically detailed.
  
  
  
  We present the first mechanical characterization of fresh, post-operative human brain tissue using an indentation loading mode. Indentation generates highly localized data, allowing structure-specific mechanical properties to be determined from small tissue samples resected during surgery. It also avoids pitfalls of cadaveric tissue and allows data to be collected before degenerative processes alter mechanical properties. To correctly predict traumatic brain injury, finite element models must calculate intracranial deformation during head impact. The functional consequences of injury depend on the anatomical structures injured. Therefore, morbidity depends on the distribution of deformation across structures. Accurate prediction of structure-specific deformation requires structure-specific mechanical properties. This data will facilitate deeper understanding of the physical mechanisms that lead to traumatic brain injury.
authors.affiliation: Department of Neurosurgery, NorthShore University Health System, 1001 University Place, Evanston, IL 60201, United States.
authors.forename: John D
authors.initials: JD
authors.lastname: Finan
authors.affiliation: Department of Biomedical Engineering, Columbia University, 351 Engineering Terrace, MC 8904, 1210 Amsterdam Avenue, New York, NY 10027, United States.
authors.forename: Sowmya N
authors.initials: SN
authors.lastname: Sundaresh
authors.affiliation: MEA Forensic Engineers & Scientists, 22 Voyager Court South, Toronto, ON M9W 5M7, Canada.
authors.forename: Benjamin S
authors.initials: BS
authors.lastname: Elkin
authors.affiliation: Department of Neurological Surgery, Columbia University Medical Center, New York Presbyterian Hospital, 710 West 168th Street, New York, NY 10032, United States.
authors.forename: Guy M
authors.initials: GM
authors.lastname: McKhann
authors.affiliation: Department of Biomedical Engineering, Columbia University, 351 Engineering Terrace, MC 8904, 1210 Amsterdam Avenue, New York, NY 10027, United States. Electronic address: Bm2119@columbia.edu.
authors.forename: Barclay
authors.initials: B
authors.lastname: Morrison
mesh_terms: D000070642:Brain Injuries, Traumatic / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology; D003198:Computer Simulation; D006624:Hippocampus / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology; D006801:Humans; D008959:Models, Neurological; D066127:White Matter / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology
keywords: Cortex; Hippocampus; Human brain; Material properties; Viscoelasticity