title: Porohyperelastic anatomical models for hydrocephalus and idiopathic intracranial hypertension.
abstract: OBJECTIVE
  Brain deformation can be seen in hydrocephalus and idiopathic intracranial hypertension (IIH) via medical images. The phenomenology of local effects, brain shift, and raised intracranial pressure and herniation are textbook concepts. However, there are still uncertainties regarding the specific processes that occur when brain tissue is subject to the mechanical stress of different temporal and spatial profiles of the 2 neurological disorders. Moreover, recent studies suggest that IIH and hydrocephalus may be diseases with opposite pathogenesis. Nevertheless, the similarities and differences between the 2 subjects have not been thoroughly investigated.
  
  
  METHODS
  An anatomical porohyperelastic finite element model was used to assess the brain tissue responses associated with hydrocephalus and IIH. The same set of boundary conditions, with the exception of brain loading for development of the transmantle pressure gradient, was applied for the 2 models. The distribution of stress and strain during tissue distortion is described by the mechanical parameters.
  
  
  RESULTS
  The results of both the hydrocephalus and IIH models correlated with pathological characteristics. For the hydrocephalus model, periventricular edema was associated with the presence of positive volumetric strain and void ratio in the lateral ventricle horns. By contrast, the IIH model revealed edema across the cerebral mantle, including the centrum semiovale, with a positive void ratio and volumetric strain.
  
  
  CONCLUSIONS
  The model simulates all the clinical features in correlation with the MR images obtained in patients with hydrocephalus and IIH, thus providing support for the role of the transmantle pressure gradient and capillary CSF absorption in CSF-related brain deformation. The finite element methods can be used for a better understanding of the pathophysiological mechanisms of neurological disorders associated with parenchymal volumetric fluctuation.
authors: 1Department of Brain and Cognitive Engineering, Korea University;
authors: Hakseung
authors: H
authors: Kim
authors: 1Department of Brain and Cognitive Engineering, Korea University;
authors: Byoung-Kyong
authors: BK
authors: Min
authors: 1Department of Brain and Cognitive Engineering, Korea University;
authors: Dae-Hyeon
authors: DH
authors: Park
authors: 1Department of Brain and Cognitive Engineering, Korea University;
authors: Stanley
authors: S
authors: Hawi
authors: 2Department of Neurology, Korea University College of Medicine, Seoul, South Korea;
authors: Byung-Jo
authors: BJ
authors: Kim
authors: 3Department of Neurosurgery, Addenbrooke's Hospital, University of Cambridge; and.
authors: Zofia
authors: Z
authors: Czosnyka
authors: 3Department of Neurosurgery, Addenbrooke's Hospital, University of Cambridge; and.
authors: Marek
authors: M
authors: Czosnyka
authors: 4Department of Engineering, University of Cambridge, United Kingdom.
authors: Michael P F
authors: MP
authors: Sutcliffe
authors: 1Department of Brain and Cognitive Engineering, Korea University;
authors: Dong-Joo
authors: DJ
authors: Kim
mesh_terms: D001921:Brain / Q000473:pathology*; D003198:Computer Simulation; D006801:Humans; D006849:Hydrocephalus / Q000473:pathology*; D008953:Models, Anatomic; D011559:Pseudotumor Cerebri / Q000473:pathology*
keywords: FE = finite element; FEM = FE model; IIH = idiopathic intracranial hypertension; bi-phase; biomechanics; cerebrospinal fluid; finite element model; hydrocephalus; idiopathic intracranial hypertension