Numerical Analysis of Elasticity Measurement of Soft Tissues via a 2D Distributed-Deflection Sensor: Significance of Tissue Parameters

2017 ◽  
Author(s):  
Yichao Yang ◽  
Arthur Weidemann ◽  
Charles Tison ◽  
Zhili Hao
Keyword(s):  
Theoretical Model ◽  
Soft Tissue ◽  
Soft Tissues ◽  
Numerical Study ◽  
Tissue Elasticity ◽  
Tissue Thickness ◽  
Compression Depth ◽  
Testing Method ◽  
Tissue Region ◽  
Elasticity Measurement

This paper reports on a numerical study on how the elasticity of soft tissue measured by a Compression-Relaxation (C-R) testing method via a two-dimensional (2D) distributed-deflection sensor varies with the tissue parameters (i.e., elasticity, thickness and in-plane dimension). The 2D sensor entails a polydimethylsiloxane (PDMS) micro structure embedded with a 3×3 sensing-plate/transducer array deposited on a Pyrex substrate. By moving the 2D sensor against a soft tissue region with a pre-defined compression pattern, the average deflection-depth slope of the deflections of the sensing-plate array versus the compression depth of the testing tissue is measured, and is translated to the measured tissue elasticity via a 1D theoretical model. Since the measured tissue elasticity arises from the tissue-sensor interaction, a numerical model, which includes the 2D sensor and a soft tissue underneath, is created in COMSOL to investigate the sensitivity of the measured tissue elasticity to tissue parameters including tissue thickness, in-plane dimension and elasticity. The numerical results reveal that the theoretical model causes a 20% overestimate on the inherent tissue elasticity in the range of 25kPa∼200kPa. The measured tissue elasticity does not vary with tissue thickness when tissue thickness is above 6mm. However, a relatively thin tissue leads to higher measured tissue elasticity. As long as the tissue in-plane dimension is larger than the sensor in-plane dimension, the measured tissue elasticity is insensitive to the tissue in-plane dimension.

Soft Tissue Thickness Variations of the Nose: A Radiological Study

2020 ◽  
Vol 40 (7) ◽  
pp. 711-718
Author(s):  
Melekber Çavuş Özkan ◽  
Fatma Yeşil ◽  
İnci Bayramiçli ◽  
Mehmet Bayramiçli
Keyword(s):  
Soft Tissue ◽  
Soft Tissues ◽  
Soft Tissue Coverage ◽  
Limited Information ◽  
Tissue Thickness ◽  
Level Of Evidence ◽  
Age And Gender ◽  
Soft Tissue Envelope ◽  
Soft Tissue Thickness ◽  
And Gender

Abstract Background Soft tissue thickness (STT) is a major factor affecting the outcome in rhinoplasty. However, limited information is found in the literature on the age- and gender-related variations of the nasal STT. Objectives The purpose of this study was to measure STT at various landmarks over the nasal framework and compare the age- and gender-related differences. Methods STT measurements were made at 11 landmarks in 325 patients by employing magnetic resonance imaging. Patients were divided into subgroups to compare the STT differences between female and male and between the age groups as young, middle age, and elderly. Results Soft tissue was thickest at the nasion and thinnest at the rhinion. The soft tissue coverage was significantly thicker in the male population at the supratip, tip, nasal bones, upper lateral cartilages, and alar lobules, whereas it is thicker in females at the rhinion. Average thickness of the soft tissues over the entire nasal framework increases with age except the rhinion. Conclusions The STT is variable over different parts of the osteocartilaginous framework. Gender and age influence the STT. The soft tissue is thicker at the distal half of the nose in male patients, and these areas become gradually thicker with age, whereas the soft tissue over the midvault becomes thinner. Increasing age presents a particular challenge to achieve predictable results in rhinoplasty, and an understanding of the soft tissue envelope allows for improved aesthetic outcome. Level of Evidence 2

scholarly journals Modifications of Midfacial Soft-Tissue Thickness Among Different Skeletal Classes in Italian Children

2018 ◽  
Vol 10 (1) ◽  
pp. 1-8
Author(s):  
Daniele Gibelli ◽  
Matteo Zago ◽  
Annalisa Cappella ◽  
Claudia Dolci ◽  
Chiarella Sforza
Keyword(s):  
Soft Tissue ◽  
Soft Tissues ◽  
Class Ii ◽  
Class Iii ◽  
Tissue Thickness ◽  
Facial Soft Tissue ◽  
Skeletal Class ◽  
Soft Tissue Thickness ◽  
Italian Children ◽  
The Relationship

Background: The anatomical assessment of the arrangement of facial soft tissues has important applications in different fields from orthodontics to plastic surgery. One of the issues concerns the relationship between facial soft tissue thickness and skeletal class. Literature mainly deals with adult populations, whereas very few studies have been focused on children. Objective: This study aims at investigating the relationship between midline facial soft tissue thickness and skeletal classes in Italian pre-treatment orthodontic child patients. Methods: Lateral cephalometric X-ray films were obtained from 220 healthy Caucasoid children (91 males and 129 females), aged between 6 and 18 years (Class I: 41 males and 70 females; Class II: 18 males and 25 females; Class III: 32 males and 34 females). All the films were digitized and 14 soft tissue thicknesses were measured on the midface; in addition, the skeletal class was assessed according to the corrected ANB angle (ANBc). Differences in facial soft tissue thickness according to sex and skeletal class were assessed through two-way ANOVA test (p<0.01). Results: Statistically significant differences according to sex were found for labrale superius, stomion and labrale inferius, with thicker soft tissues in males than in females (p<0.01). Only measurements at labrale superius and gnathion showed statistically significant differences according to skeletal class, with thicker soft tissues in Class III children and thinner ones in Class II children (p<0.01). Conclusion: The limited number of investigations, as well as the differences in protocols, renders the comparison of results from different studies difficult, suggesting further investigations to enlighten this complex and debated anatomical issue.

scholarly journals Theoretical model of guided waves in a bone-mimicking plate coupled with soft-tissue layers

2021 ◽  
Author(s):  
Hoai Nguyen ◽  
Ductho Le ◽  
Emmanuel Plan ◽  
Son Tung Dang ◽  
Haidang Phan
Keyword(s):  
Theoretical Model ◽  
Soft Tissue ◽  
Quantitative Ultrasound ◽  
Guided Waves ◽  
Soft Tissues ◽  
Wave Interaction ◽  
Ultrasonic Waves ◽  
Time Harmonic ◽  
Phase And Group Velocities ◽  
Wave Modes

Quantitative ultrasound has shown a significant promise in the assessment of bone characteristics in the recent reports. However, our understanding of wave interaction with bone tissues is still far from complete since the propagation of ultrasonic waves in bones is a very challenging topic due to their multilayer nature. The aim of the current study is to develop a theoretical model for guided waves in a bone-mimicking plate coupled with two soft-tissue layers. Here, the bone plate is modeled as an isotropic solid layer while the soft tissues are modeled as fluid layers. Based on the boundary conditions set for the three-layered structure, a characteristic equation is obtained which results in dispersion curves of the phase and group velocities. New expressions for free guided waves propagating in the trilayered plate are introduced. The amplitudes of wave modes generated by time-harmonic loads applied in the plate are theoretically computed by reciprocity consideration. As an example of calculation, the normalized amplitudes of the lowest wave modes are presented. The obtained results and equations discussed in this study could be, in general, useful for further applications in the area of bone quantitative ultrasound.

scholarly journals Plantar soft tissues and Achilles tendon thickness and stiffness in people with diabetes: a systematic review

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Benedictine Yen Chen Khor ◽  
James Woodburn ◽  
Lisa Newcombe ◽  
Ruth Barn
Keyword(s):  
Systematic Review ◽  
Soft Tissue ◽  
Achilles Tendon ◽  
Methodological Quality ◽  
Soft Tissues ◽  
Tissue Stiffness ◽  
Tissue Thickness ◽  
Tendon Stiffness ◽  
Structural Differences ◽  
Tendon Thickness

Abstract Background Diabetes mellitus is associated with changes in soft tissue structure and function. However, the directionality of this change and the extent to which either tissue thickness or stiffness contributes to the pathogenesis of diabetes-related foot ulcerations is unclear. Hence, this systematic review aims to summarise the existing evidence for soft tissue structural differences in the feet of people with and without diabetes. Methods In compliance with MOOSE and PRISMA guidelines, AMED, CINAHL, MEDLINE, ProQuest Health & Medical Collection, ProQuest Nursing & Allied Health Database, and Web of Science electronic databases were systematically searched for studies published from database inception until 1st October 2020 [Prospero CRD42020166614]. Reference lists of included studies were further screened. Methodological quality was appraised using a modified critical appraisal tool for quantitative studies developed by McMaster University. Results A total of 35 non-randomised observational studies were suitable for inclusion. Within these, 20 studies evaluated plantar tissue thickness, 19 studies evaluated plantar tissue stiffness, 9 studies evaluated Achilles tendon thickness and 5 studies evaluated Achilles tendon stiffness outcomes. No significant differences in plantar tissue thickness were found between people with and without diabetes in 55% of studies (11/20), while significantly increased plantar tissue stiffness was found in people with diabetes in 47% of studies (9/19). Significantly increased Achilles tendon thickness was found in people with diabetes in 44% of studies (4/9), while no significant differences in Achilles tendon stiffness were found between people with and without diabetes in 60% of studies (3/5). Conclusions This systematic review found some evidence of soft tissue structural differences between people with and without diabetes. However, uncertainty remains whether these differences independently contribute to diabetes-related foot ulcerations. The heterogeneity of methodological approaches made it difficult to compare across studies and methodological quality was generally inadequate. High-quality studies using standardised and validated assessment techniques in well-defined populations are required to determine more fully the role of structural tissue properties in the pathogenesis of diabetes-related foot ulcerations.

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