Shear Wave Propagation of the Ferret Brain at Multiple Frequencies In Vivo

2012 ◽  
Author(s):  
Yuan Feng ◽  
Yulin Chang ◽  
Erik H. Clayton ◽  
Ruth J. Okamoto ◽  
Philip V. Bayly
Keyword(s):  
Mathematical Modeling ◽  
Mechanical Properties ◽  
White Matter ◽  
Loss Modulus ◽  
Tissue Properties ◽  
In Vivo Measurement ◽  
Dissipative Effects ◽  
Multiple Frequencies ◽  
The Brain

Mathematical modeling and computer simulations are widely used for understanding traumatic brain injury (TBI). However, accurate tissue parameters are needed, especially for the brain in vivo. In this study, we used the ferret as the animal model because it is the smallest mammal with a folded brain and significant white matter tracts. Magnetic resonance elastography (MRE) has proven useful for in vivo measurement of biological tissue properties. Mechanical properties of the ferret brain over a range of frequencies from 400–800 Hz were studied using MRE. Experiment results show both that storage and loss modulus increases with frequency and that dissipative effects in the white matter (characterized by the loss modulus G″) were significant larger than in gray matter.

What Has Direct Cortical and Subcortical Electrostimulation Taught Us about Neurolinguistics?

2019 ◽  
pp. 185-211
Author(s):  
Hugues Duffau
Keyword(s):  
White Matter ◽  
Large Scale ◽  
Functional Neuroimaging ◽  
Great Accuracy ◽  
Subcortical White Matter ◽  
Cerebral Lesions ◽  
Physiological Basis ◽  
Postoperative Mri ◽  
The Brain

Investigating the neural and physiological basis of language is one of the most important challenges in neurosciences. Direct electrical stimulation (DES), usually performed in awake patients during surgery for cerebral lesions, is a reliable tool for detecting both cortical and subcortical (white matter and deep grey nuclei) regions crucial for cognitive functions, especially language. DES transiently interacts locally with a small cortical or axonal site, but also nonlocally, as the focal perturbation will disrupt the entire subnetwork sustaining a given function. Thus, in contrast to functional neuroimaging, DES represents a unique opportunity to identify with great accuracy and reproducibility, in vivo in humans, the structures that are actually indispensable to the function, by inducing a transient virtual lesion based on the inhibition of a subcircuit lasting a few seconds. Currently, this is the sole technique that is able to directly investigate the functional role of white matter tracts in humans. Thus, combining transient disturbances elicited by DES with the anatomical data provided by pre- and postoperative MRI enables to achieve reliable anatomo-functional correlations, supporting a network organization of the brain, and leading to the reappraisal of models of language representation. Finally, combining serial peri-operative functional neuroimaging and online intraoperative DES allows the study of mechanisms underlying neuroplasticity. This chapter critically reviews the basic principles of DES, its advantages and limitations, and what DES can reveal about the neural foundations of language, that is, the large-scale distribution of language areas in the brain, their connectivity, and their ability to reorganize.

Reliability Investigation of Tissue Resonator Indenter Device

2010 ◽  
Author(s):  
Ming Jia ◽  
Jean W. Zu ◽  
Alireza Hariri
Keyword(s):  
Mechanical Properties ◽  
Soft Tissue ◽  
Soft Tissues ◽  
Tissue Properties ◽  
University Of Toronto ◽  
In Vivo Measurements ◽  
Disease Diagnostics ◽  
Working Principle ◽  
The University

Knowledge of tissue mechanical properties is widely required by medical applications, such as disease diagnostics, surgery operation, simulation, planning, and training. A new portable device, called Tissue Resonator Indenter Device (TRID), has been developed for measurement of regional viscoelastic properties of soft tissues at the Bio-instrument and Biomechanics Lab of the University of Toronto. As a device for soft tissue properties in-vivo measurements, the reliability of TRID is crucial. This paper presents TRID’s working principle and the experimental study of TRID’s reliability with respect to inter-reliability, intra-reliability, and the indenter misalignment effect as well. The experimental results show that TRID is a reliable device for in-vivo measurements of soft tissue mechanical properties.

Determination of In-Vivo Elastic Properties of Soft Tissue Using Magnetic Resonance Elastography

2003 ◽  
Author(s):  
Francis E. Kennedy ◽  
Marvin M. Doyley ◽  
Elijah E. W. Van Houten ◽  
John B. Weaver ◽  
Keith D. Paulsen
Keyword(s):  
Magnetic Resonance ◽  
Soft Tissue ◽  
Elastic Properties ◽  
Magnetic Resonance Elastography ◽  
Tissue Properties ◽  
In Vivo Measurement ◽  
Ultrasonic Methods ◽  
Accurate Quantification

In-vivo measurement of the elastic properties of soft tissue have been made using a variety of direct techniques, such as indentation probes and rotary shear actuators, but they are unable to access much of the soft tissue of interest. Indirect ultrasonic methods for imaging elastic properties of soft tissue were first introduced about 15 years ago, see Ophir (1991). Although the results of ultrasonic elastography studies have been quite promising, they may not be suited for applications requiring accurate quantification of soft tissue properties. An alternative to ultrasound, magnetic resonance imaging, has the advantage of enabling precise measurement of all three components of tissue displacement. The reconstruction of elastic properties from the imaged displacement field is called magnetic resonance elastography (MRE), and is the subject of this paper.

Real Time In Vivo Measurement of Ascorbate in the Brain Using Carbon Nanotube-Modified Microelectrodes

2013 ◽  
Vol 25 (7) ◽  
pp. 1757-1763 ◽  
Author(s):  
Nuno R. Ferreira ◽  
Ricardo M. Santos ◽  
João Laranjinha ◽  
Rui M. Barbosa
Keyword(s):  
Carbon Nanotube ◽  
Real Time ◽  
In Vivo Measurement ◽  
The Brain

Gender-specific in vivo measurement of the structural and mechanical properties of the human patellar tendon

2007 ◽  
Vol 25 (12) ◽  
pp. 1635-1642 ◽  
Author(s):  
Gladys N.L. Onambélé ◽  
Katherine Burgess ◽  
Stephen J. Pearson
Keyword(s):  
Mechanical Properties ◽  
Patellar Tendon ◽  
In Vivo Measurement ◽  
Gender Specific

Development of novel techniques in vivo measurement of mechanical properties of periodontal ligament

2006 ◽  
Vol 39 ◽  
pp. S201-S202 ◽  
Author(s):  
H. Liu ◽  
S.L. Evans ◽  
C. Holt ◽  
A. Zhurov ◽  
J. Middleton ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Periodontal Ligament ◽  
In Vivo Measurement

scholarly journals The brain interstitial system: Anatomy, modeling, in vivo measurement, and applications

2017 ◽  
Vol 157 ◽  
pp. 230-246 ◽  
Author(s):  
Yiming Lei ◽  
Hongbin Han ◽  
Fan Yuan ◽  
Aqeel Javeed ◽  
Yong Zhao
Keyword(s):  
In Vivo Measurement ◽  
The Brain

scholarly journals Fabrication and Modeling of Dynamic Multipolymer Nanofibrous Scaffolds

2009 ◽  
Vol 131 (10) ◽  
Author(s):  
Brendon M. Baker ◽  
Nandan L. Nerurkar ◽  
Jason A. Burdick ◽  
Dawn M. Elliott ◽  
Robert L. Mauck
Keyword(s):  
Mechanical Properties ◽  
Rational Design ◽  
Cell Infiltration ◽  
Tissue Properties ◽  
Matrix Deposition ◽  
Native Tissue ◽  
Nanofibrous Scaffolds ◽  
Wide Range ◽  
Anisotropic Mechanical Properties

Aligned nanofibrous scaffolds hold tremendous potential for the engineering of dense connective tissues. These biomimetic micropatterns direct organized cell-mediated matrix deposition and can be tuned to possess nonlinear and anisotropic mechanical properties. For these scaffolds to function in vivo, however, they must either recapitulate the full dynamic mechanical range of the native tissue upon implantation or must foster cell infiltration and matrix deposition so as to enable construct maturation to meet these criteria. In our recent studies, we noted that cell infiltration into dense aligned structures is limited but could be expedited via the inclusion of a distinct rapidly eroding sacrificial component. In the present study, we sought to further the fabrication of dynamic nanofibrous constructs by combining multiple-fiber populations, each with distinct mechanical characteristics, into a single composite nanofibrous scaffold. Toward this goal, we developed a novel method for the generation of aligned electrospun composites containing rapidly eroding (PEO), moderately degradable (PLGA and PCL/PLGA), and slowly degrading (PCL) fiber populations. We evaluated the mechanical properties of these composites upon formation and with degradation in a physiologic environment. Furthermore, we employed a hyperelastic constrained-mixture model to capture the nonlinear and time-dependent properties of these scaffolds when formed as single-fiber populations or in multipolymer composites. After validating this model, we demonstrated that by carefully selecting fiber populations with differing mechanical properties and altering the relative fraction of each, a wide range of mechanical properties (and degradation characteristics) can be achieved. This advance allows for the rational design of nanofibrous scaffolds to match native tissue properties and will significantly enhance our ability to fabricate replacements for load-bearing tissues of the musculoskeletal system.

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