Non-invasive in vivo measurement of the shear modulus of human vocal fold tissue

In order to evaluate the mechanical properties of the human skeletal muscles, the elasticity and viscosity of the human calf muscles were measured with Magnetic Resonance Elastography (MRE). MRE is a novel method to measure the mechanical properties of living soft tissues in vivo quantitatively by observing the strain waves propagated in the object. In this study, the shear modulus and viscosity coefficient were measured with MRE. The shear modulus was 3.7 kPa in relaxed state, and increased with increasing the muscle forces. Interestingly, the viscosity was changed with the vibration frequency applied to the muscles, that was 4.5 Pa·s at 100Hz vibration and 2.4 Pa·s at 200Hz vibration. This shows clearly the visco-elastic property.

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NON-INVASIVE POLARIMETRIC GLUCOSE MEASUREMENT SYSTEM FOR EYE PHANTOMS AND IN-VIVO MEASUREMENT REQUIREMENTS

Novel Optical Instrumentation for Biomedical Applications ◽

10.1364/ecbo.2003.5143_96 ◽

2003 ◽

Author(s):

R. Rawer ◽

P. Vollmer ◽

A. Malz ◽

W. Stork ◽

K. D. Müller-Glaser

Keyword(s):

Measurement System ◽

Glucose Measurement ◽

In Vivo Measurement ◽

Non Invasive

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Noncontact Determination of the Mechanical Properties of the Human Vocal Folds

ASME 2008 Summer Bioengineering Conference, Parts A and B ◽

10.1115/sbc2008-193072 ◽

2008 ◽

Author(s):

Shinji Deguchi ◽

Kazutaka Kawashima

Keyword(s):

Mechanical Properties ◽

Vocal Fold ◽

Measurement Techniques ◽

Voice Quality ◽

Vocal Folds ◽

In Vivo Measurement ◽

In Vitro Measurements ◽

Excited Oscillation

Mechanical properties of the vocal folds (such as stiffness or viscoelastic properties) play an essential role in phonation. They affect not only voice quality but also onset threshold of vocal fold self-excited oscillation, a sound source of voice [1]. Many experimental data on the mechanical properties have been reported so far, in which in vitro [2] or in vivo measurement techniques [3] were employed. In vitro measurements give us detailed information on the mechanical properties, yet it would be required to consider possible loss of freshness of the specimen. Meanwhile, current in vivo measurement methods utilize a thin probe to deform the vocal fold tissue located at the back of the throat and hence need technical skills for the surveyor to successfully obtain its loading-deformation relationship.

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In vivo measurement of shear modulus of the human cornea using optical coherence elastography

Scientific Reports ◽

10.1038/s41598-020-74383-4 ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Antoine Ramier ◽

Amira M. Eltony ◽

YiTong Chen ◽

Fatima Clouser ◽

Judith S. Birkenfeld ◽

...

Keyword(s):

Shear Modulus ◽

Rayleigh Wave ◽

Wave Speed ◽

Critical Role ◽

Shear Stiffness ◽

Human Cornea ◽

Optical Coherence ◽

In Vivo Measurement ◽

Rayleigh Wave Speed

Abstract Corneal stiffness plays a critical role in shaping the cornea with respect to intraocular pressure and physical interventions. However, it remains difficult to measure the mechanical properties noninvasively. Here, we report the first measurement of shear modulus in human corneas in vivo using optical coherence elastography (OCE) based on surface elastic waves. In a pilot study of 12 healthy subjects aged between 25 and 67, the Rayleigh-wave speed was 7.86 ± 0.75 m/s, corresponding to a shear modulus of 72 ± 14 kPa. Our data reveal two unexpected trends: no correlation was found between the wave speed and IOP between 13–18 mmHg, and shear modulus decreases with age (− 0.32 ± 0.17 m/s per decade). We propose that shear stiffness is governed by the interfibrillar matrix, whereas tensile strength is dominated by collagen fibrils. Rayleigh-wave OCE may prove useful for clinical diagnosis, refractive surgeries, and treatment monitoring.

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