Modelling Normal Pressure Hydrocephalus as a ‘Two-Hit’ Disease Using Multiple-Network Poroelastic Theory

2010 ◽  
Author(s):  
Brett Tully ◽  
Yiannis Ventikos
Keyword(s):  
Normal Pressure Hydrocephalus ◽  
Normal Pressure ◽  
Brain Parenchyma ◽  
Strongly Correlated ◽  
Clinical Markers ◽  
Cerebral Diseases ◽  
Spatio Temporal ◽  
Multiple Network ◽  
Poroelastic Theory ◽  
The Brain

The evolution of many cerebral diseases such as Alzheimer’s and Parkinson’s Disease, Hydrocephalus, Cerebral Oedema, Stroke, and Tumour are strongly correlated to a change in the transport properties of fluid in the brain. This research proposes a novel application of Multiple-Network Poroelastic Theory (MPET) to investigate cerebral hydrodynamics through a detailed investigation of multiscalar, spatio-temporal transport of fluid between the cerebral blood, cerebrospinal fluid (CSF) and brain parenchyma. Specifically, MPET is used to interrogate the clinical markers of Normal Pressure Hydrocephalus (NPH).

Cerebral water transport using multiple-network poroelastic theory: application to normal pressure hydrocephalus

2010 ◽  
Vol 667 ◽  
pp. 188-215 ◽  
Author(s):  
B. TULLY ◽  
Y. VENTIKOS
Keyword(s):  
Water Transport ◽  
Normal Pressure Hydrocephalus ◽  
Normal Pressure ◽  
Brain Parenchyma ◽  
Population Demographics ◽  
Theory Application ◽  
Spatio Temporal ◽  
Multiple Network ◽  
Consistent Treatment ◽  
Poroelastic Theory

The twenty-first century is bearing witness to a drastic change in population demographics and diseases of old age, such as dementia, are placing an unprecedented burden on the global healthcare system. Normal pressure hydrocephalus may be the only curable form of dementia, yet its pathophysiology is paradoxical and a consistent treatment currently remains elusive. A novel application of multiple-network poroelastic theory (MPET) is proposed to investigate water transport in the cerebral environment. Specifically, MPET is modified to allow a detailed investigation of spatio-temporal transport of fluid between the cerebral blood, cerebrospinal fluid (CSF) and brain parenchyma across scales. This framework thus allows an exploration of hypotheses defining the initiation and progression of both acute and chronic hydrocephalus. Results show that a breakdown in the transport mechanisms between the arterial vascular network and interstitial space within the parenchyma may be a cause of accumulation of CSF in the ventricles. Specifically, there must be an increase in the compliance of the arteriole/capillary network, which may combine with a breakdown in the blood–CSF barrier to allow an increased flow from the arteriole/capillary blood to the CSF. The results of this study should prove useful to guide experimental exploration in areas that warrant further investigation and validation.

scholarly journals Finite Element Analysis of Normal Pressure Hydrocephalus: Influence of CSF Content and Anisotropy in Permeability

2010 ◽  
Vol 7 (3) ◽  
pp. 187-197 ◽  
Author(s):  
K. Shahim ◽  
J.-M. Drezet ◽  
J.-F. Molinari ◽  
R. Sinkus ◽  
S. Momjian
Keyword(s):  
Finite Element ◽  
Normal Pressure Hydrocephalus ◽  
Diffusion Tensor ◽  
Great Influence ◽  
Normal Pressure ◽  
Element Model ◽  
Brain Parenchyma ◽  
Element Analysis ◽  
Cerebral Disease ◽  
The Brain

Hydrocephalus is a cerebral disease where brain ventricles enlarge and compress the brain parenchyma towards the skull leading to symptoms like dementia, walking disorder and incontinence. The origin of normal pressure hydrocephalus is still obscure. In order to study this disease, a finite element model is built using the geometries of the ventricles and the skull measured by magnetic resonance imaging. The brain parenchyma is modelled as a porous medium fully saturated with cerebrospinal fluid (CSF) using Biot's theory of consolidation (1941). Owing to the existence of bundles of axons, the brain parenchyma shows locally anisotropic behaviour. Indeed, permeability is higher along the fibre tracts in the white matter region. In contrast, grey matter is isotropic. Diffusion tensor imaging is used to establish the local CSF content and the fibre tracts direction together with the associated local frame where the permeability coefficients are given by dedicated formulas. The present study shows that both inhomogeneous CSF content and anisotropy in permeability have a great influence on the CSF flow pattern through the parenchyma under an imposed pressure gradient between the ventricles and the subarachnoid spaces.

scholarly journals Normal pressure hydrocephalus - active and passive pathogenic mechanisms

2013 ◽  
Vol 20 (3) ◽  
pp. 241-247
Author(s):  
St.M. Iencean ◽  
Al. Tascu ◽  
A.St. Iencean ◽  
I. Poeata ◽  
M.R. Gorgan
Keyword(s):  
Normal Pressure Hydrocephalus ◽  
Normal Pressure ◽  
Brain Parenchyma ◽  
Long Term Results ◽  
Communicating Hydrocephalus ◽  
Ventricular Wall ◽  
Short Term ◽  
Clinical Triad ◽  
The Brain

Abstract Normal pressure hydrocephalus (NPH) is characterized by normal CSF pressure, less than 18 cm H2O, classical clinical triad: gait disturbance, dementia and incontinence in patients with communicating hydrocephalus on CT or MRI. We analyzed retrospectively the NPH hospitalized patients in three neurosurgical departments between July 2007 and December 2012. Only the cases who met all diagnostic criteria were selected for this study. There were 47 selected cases of patients with NPH, including 24 patients with secondary NPH and 23 patients with idiopathic NPH. Ventriculo-peritoneal shunt was performed in all 24 patients with secondary NPH and at 11 patients with IdNPH. The short-term and long-term results were good and very good for cases of secondary NPH and good in 60% and poor in 40% in cases of IdNPH. The MR imaging showed the absence of CSF passage through the ventricular wall and the ventricular wall in cases of IdNPH with poor results after shunting: ependyma and glia limitans interna represents a fluid - parenchymal barrier between the brain parenchyma and the ventricles as a glialependymal barrier. We can consider that secondary NPH and some cases of idiopathic NPH with repeated small increases of ICP, with transependymal migration of CSF and hydrocephalus causing clinical triad because of the open glial-ependymal barrier, as an Active Normal Pressure Hydrocephalus and the shunt has good results. Other cases of IdNPH have not increases of intracranial pressure, no transependymal migration of CSF and there are periventricular deep lesions, without brain atrophy, causing clinical triad, as a passive hydrocephalus, it is a Passive Normal Pressure Hydrocephalus.

Nonlinear poroplastic model of ventricular dilation in hydrocephalus

2008 ◽  
Vol 109 (1) ◽  
pp. 100-107 ◽  
Author(s):  
Shahan Momjian ◽  
Denis Bichsel
Keyword(s):  
Brain Tissue ◽  
Normal Pressure ◽  
Porous Matrix ◽  
Brain Parenchyma ◽  
Plastic Behavior ◽  
Fe Model ◽  
Mechanical Behaviors ◽  
Ventricular Dilation ◽  
Numerical Finite Element ◽  
The Brain

Object The mechanism of ventricular dilation in normal-pressure hydrocephalus remains unclear. Numerical finite-element (FE) models of hydrocephalus have been developed to investigate the biomechanics of ventricular enlargement. However, previous linear poroelastic models have failed to reproduce the relatively larger dilation of the horns of the lateral ventricles. In this paper the authors instead elaborated on a nonlinear poroplastic FE model of the brain parenchyma and studied the influence of the introduction of these potentially more realistic mechanical behaviors on the prediction of the ventricular shape. Methods In the proposed model the elasticity modulus varies as a function of the distension of the porous matrix, and the internal mechanical stresses are relaxed after each iteration, thereby simulating the probable plastic behavior of the brain tissue. The initial geometry used to build the model was extracted from CT scans of patients developing hydrocephalus, and the results of the simulations using this model were compared with the real evolution of the ventricular size and shape in the patients. Results The authors' model predicted correctly the magnitude and shape of the ventricular dilation in real cases of acute and chronic hydrocephalus. In particular, the dilation of the frontal and occipital horns was much more realistic. Conclusions This finding suggests that the nonlinear and plastic mechanical behaviors implemented in the present numerical model probably occur in reality. Moreover, the availability of such a valid FE model, whose mechanical parameters approach real mechanical properties of the brain tissue, might be useful in the further modeling of ventricular dilation at a normal pressure.

In vivo viscoelastic properties of the brain in normal pressure hydrocephalus

2010 ◽  
pp. n/a-n/a ◽  
Author(s):  
Kaspar-Josche Streitberger ◽  
Edzard Wiener ◽  
Jan Hoffmann ◽  
Florian Baptist Freimann ◽  
Dieter Klatt ◽  
...  
Keyword(s):  
Normal Pressure Hydrocephalus ◽  
Viscoelastic Properties ◽  
Normal Pressure ◽  
The Brain

Cerebral cysticercosis with aqueductal obstruction

1980 ◽  
Vol 53 (2) ◽  
pp. 252-255 ◽  
Author(s):  
Tung Pui Poon ◽  
Edward J. Arida ◽  
Wolodymyr P. Tyschenko
Keyword(s):  
Intracranial Hypertension ◽  
Brain Stem ◽  
Normal Pressure Hydrocephalus ◽  
Signs And Symptoms ◽  
Normal Pressure ◽  
Content Type ◽  
Neurological Signs ◽  
Cerebral Cysticercosis ◽  
The Brain ◽  
Fine Print

✓ The authors report a case of cerebral cysticercosis which presented with generalized nonspecific neurological signs and symptoms attributed to acute aqueductal obstruction, with concomitant intracranial hypertension. These were characteristic intracranial calcifications along with angiographically demonstrated signs of hydrocephalus. Contrast encephalography clearly demonstrated aqueductal obstruction. Pathologically, the aqueductal obstruction was shown to be due to parasitic invasion of the brain stem with compression of the aqueduct. The presence of typical intracranial calcification in conjunction with either obstructive or normal-pressure hydrocephalus should alert the observer to the possibility of cerebral cysticercosis.

Progressive Expanding Congenital Porencephalies: A Treatable Cause of Progressive Encephalopathy

PEDIATRICS ◽  
1981 ◽  
Vol 68 (2) ◽  
pp. 198-202
Author(s):  
Marc Tardieu ◽  
Philippe Evrard ◽  
Gilles Lyon
Keyword(s):  
Brain Lesion ◽  
Normal Pressure ◽  
Brain Parenchyma ◽  
Motor Deficits ◽  
Ventriculoperitoneal Shunting ◽  
Progressive Encephalopathy ◽  
Computed Tomography Scans ◽  
Gradual Expansion ◽  
Normal Thickness ◽  
The Brain

In congenital porencephalies, diverticulation of the lateral ventricle is a dynamic process producing compression and stretching of the brain tissue bordering the diverticulum, bulging of the overlying skull, macrocephaly, and occasionally progressive neurologic signs (hemiplegia, raised intracranial pressure), even when the rest of the ventricular system is not dilated and the CSF pressure is normal. Ventriculoperitoneal shunting can result in remarkable improvement of focal motor deficits and may apparently also play a beneficial role on further mental development. Successive computed tomography scans demonstrate that the brain parenchyma, which had been stretched by the porencephalic pouch, is capable of regaining near normal thickness. Congenital porencephalies are initiated by a limited destructive brain lesion, but the gradual expansion of the ventricular herniation may imply a mechanism identical to that which has been postulated in normal pressure hydrocephalus. Nine cases of unilateral "expanding" congenital porencephalies are presented and the treatment of this condition is discussed.

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