The impact of aging and gender on brain viscoelasticity

Sack, Ingolf; Beierbach, Bernd; Wuerfel, Jens; Klatt, Dieter; Hamhaber, Uwe; Papazoglou, Sebastian; Martus, Peter; Braun, Jürgen

doi:10.1016/j.neuroimage.2009.02.040

Cited by 372 publications

(387 citation statements)

References 25 publications

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“…Here we assume that the mechanical properties of the woodpecker's brain and dura matter are the same as the human being's, [11][12][13][14][15] the components except the beak and hyoid are linear-viscoelasticity. Simply the viscosity parameters of the dead brain and dura matter are referenced to the work of Sack et al 12 and the viscosity of bone is referenced to those of Lunde et al 16 and Matthew et al 17 The wood is considered as the spruce wood, 18 which is a kind of the woodpecker's favorite trees. The material properties used in this paper are given in Table I. A symmetrical FE model mainly composed of tetrahedral elements is set up based on the geometrical model, which contains more than 256,000 nodes and 1,192,000 elements, the components of the model are shown in Fig.…”

Section: B Materials Properties and The Fe Modelmentioning

confidence: 99%

Numerical study of the impact response of woodpecker's head

Zhu

Guo

et al. 2012

AIP Advances

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Woodpecker can beat trees 20-25 times per second and lasts for several seconds, with a 1200 g deceleration, but it appears that they never get brain concussion. How does the stress wave propagate from the beak tip to brain and how does a woodpecker protect itself from brain damage? In this paper, we establish a finite element model of typical woodpecker head based on its X-ray tomography images and conduct the numerical analysis of the impact response of the woodpecker's head by using a viscoelasticity material model. Especially, the woodpecker head response to an impact speed of 7 m/s is investigated to explore the stress concentration zone and how the stress wave propagates in its head. The numerical results show that the stress wave in the head propagates from the upper beak to back skull and is reduced by the specific structure of hyoid and viscoelasticity of biomaterials. The maximum stresses in skull and brain are both below the safe level. The stress in skull almost disappears before the next impact. The stress in brain lasts for a little longer but shows smaller value with little variation. The stress is impossible to accumulate in the limited pecking time, so the brain damage can be avoided

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Section: B Materials Properties and The Fe Modelmentioning

confidence: 99%

Numerical study of the impact response of woodpecker's head

Zhu

Guo

et al. 2012

AIP Advances

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“…An important restriction that has to be considered prior to usage of such an actuator type is its limitation to lowfrequency excitation [8]. Recently published brain elastography studies exploited frequencies in the range of 25-100 Hz [10], [12] and [14]. This is very similar to the frequency range achieved with a pneumatic approach, where a loud speaker is connected to a flexible hose itself connected to an actuator placed near the organ of interest [15], [16] and [17].…”

Section: Methodsmentioning

confidence: 99%

Convertible pneumatic actuator for magnetic resonance elastography of the brain

Latta

Gruwel

Debergue

et al. 2011

Magnetic Resonance Imaging

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Here we present a novel pneumatic actuator design for brain magnetic resonance elastography (MRE). Magnetic resonance elastography is a phase contrast technique capable of tracing strain wave propagation and utilizing this information for the calculation of mechanical properties of materials and living tissues. In MRE experiments, the acoustic waves are generated in a synchronized way with respect to image acquisition, using various types of mechanical actuators. The unique feature of the design is its simplicity and flexibility, which allows reconfiguration of the actuator for different applications ranging from in vivo brain MRE to experiments with phantoms. Phantom and in vivo data are presented to demonstrate actuator performance.

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“…For biological tissues, there is a consensus that power law models are the most suitable for characterizing the observed frequency behavior (dispersion) of G(x). 105,106 In these models, the frequency variation of G(x) involves terms raised to fractional powers (typically described by a, where 0 < a < 1). 107 A rheological model exhibiting an a power law dispersion is the so-called springpot (or single fractional element).…”

Section: Magnetic Resonance Elastographymentioning

confidence: 99%

Monitoring Cartilage Tissue Engineering Using Magnetic Resonance Spectroscopy, Imaging, and Elastography

Kotecha

Klatt

Magin

2013

Tissue Engineering Part B: Reviews

Self Cite

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A key technical challenge in cartilage tissue engineering is the development of a noninvasive method for monitoring the composition, structure, and function of the tissue at different growth stages. Due to its noninvasive, three-dimensional imaging capabilities and the breadth of available contrast mechanisms, magnetic resonance imaging (MRI) techniques can be expected to play a leading role in assessing engineered cartilage. In this review, we describe the new MR-based tools (spectroscopy, imaging, and elastography) that can provide quantitative biomarkers for cartilage tissue development both in vitro and in vivo. Magnetic resonance spectroscopy can identify the changing molecular structure and alternations in the conformation of major macromolecules (collagen and proteoglycans) using parameters such as chemical shift, relaxation rates, and magnetic spin couplings. MRI provides high-resolution images whose contrast reflects developing tissue microstructure and porosity through changes in local relaxation times and the apparent diffusion coefficient. Magnetic resonance elastography uses low-frequency mechanical vibrations in conjunction with MRI to measure soft tissue mechanical properties (shear modulus and viscosity). When combined, these three techniques provide a noninvasive, multiscale window for characterizing cartilage tissue growth at all stages of tissue development, from the initial cell seeding of scaffolds to the development of the extracellular matrix during construct incubation, and finally, to the postimplantation assessment of tissue integration in animals and patients.

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The impact of aging and gender on brain viscoelasticity

Cited by 372 publications

References 25 publications

Numerical study of the impact response of woodpecker's head

Numerical study of the impact response of woodpecker's head

Convertible pneumatic actuator for magnetic resonance elastography of the brain

Monitoring Cartilage Tissue Engineering Using Magnetic Resonance Spectroscopy, Imaging, and Elastography

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