scholarly journals An Iterative Method for Estimating Nonlinear Elastic Constants of Tumor in Soft Tissue from Approximate Displacement Measurements

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Maryam Mehdizadeh Dastjerdi ◽  
Ali Fallah ◽  
Saeid Rashidi
Keyword(s):  
Soft Tissue ◽  
Iterative Method ◽  
Elastic Constants ◽  
Soft Tissues ◽  
Constitutive Models ◽  
Ultrasound Elastography ◽  
Accurate Estimation ◽  
Displacement Fields ◽  
Nonlinear Constitutive Models ◽  
Nonlinear Elastic

Objectives. Various elastography techniques have been proffered based on linear or nonlinear constitutive models with the aim of detecting and classifying pathologies in soft tissues accurately and noninvasively. Biological soft tissues demonstrate behaviors which conform to nonlinear constitutive models, in particular the hyperelastic ones. In this paper, we represent the results of our steps towards implementing ultrasound elastography to extract hyperelastic constants of a tumor inside soft tissue. Methods. Hyperelastic parameters of the unknown tissue have been estimated by applying the iterative method founded on the relation between stress, strain, and the parameters of a hyperelastic model after (a) simulating the medium’s response to a sinusoidal load and extracting the tissue displacement fields in some instants and (b) estimating the tissue displacement fields from the recorded/simulated ultrasound radio frequency signals and images using the cross correlation-based technique. Results. Our results indicate that hyperelastic parameters of an unidentified tissue could be precisely estimated even in the conditions where there is no prior knowledge of the tissue, or the displacement fields have been approximately calculated using the data recorded by a clinical ultrasound system. Conclusions. The accurate estimation of nonlinear elastic constants yields to the correct cognizance of pathologies in soft tissues.

Nonlinear Constitutive Models and the Finite Element Absolute Nodal Coordinate Formulation

2007 ◽  
Author(s):  
Luis G. Maqueda ◽  
Ahmed A. Shabana
Keyword(s):  
Absolute Nodal Coordinate Formulation ◽  
Constitutive Models ◽  
Biological Tissues ◽  
Constitutive Law ◽  
Elastic Behavior ◽  
Deformation Analysis ◽  
Absolute Nodal Coordinate ◽  
The Absolute ◽  
Nonlinear Constitutive Models ◽  
Nonlinear Elastic

In this investigation, the use of three different nonlinear constitutive models based on the hyper-elasticity theory with the absolute nodal coordinate formulation is considered. These three nonlinear constitutive models are based on the Neo-Hookean constitutive law for compressible materials, the Neo-Hookean constitutive law for incompressible materials, and the Mooney-Rivlin constitutive law in which the material is assumed to be incompressible. These models, which allow capturing Poisson modes, are suitable for many materials and applications, including rubber-like materials and biological tissues which are governed by nonlinear elastic behavior and are considered incompressible or nearly incompressible. Numerical examples that demonstrate the implementation of these nonlinear constitutive models in the absolute nodal coordinate formulation are presented. The results obtained using the nonlinear and linear constitutive models are compared in this study. The results show that when linear constitutive models are used in the large deformation analysis, singular configurations are encountered and basic formulas such as Nanson’s formula are no longer valid. These singular deformation configurations are not encountered when the nonlinear constitutive models are used.

Experimental Validation Technique for Constitutive Models Describing Behavior of Soft Tissue Surrogates During Projectile Penetration

2010 ◽  
Author(s):  
Ericka K. Amborn ◽  
Karim H. Muci-Ku¨chler ◽  
Brandon J. Hinz
Keyword(s):  
Soft Tissue ◽  
Mechanical Behavior ◽  
High Speed ◽  
Soft Tissues ◽  
Constitutive Models ◽  
Model Parameters ◽  
Channel Deformations ◽  
Single Term ◽  
Sensitivity Studies ◽  
Element Erosion

Numerical simulations of ballistic penetration of soft tissues are particularly difficult to validate because relevant experimental data is not readily available. Efficient, controlled, high strain rate experiments involving large deformations must be developed for that purpose. This paper proposes an axisymmetric experiment to validate constitutive models describing the bulk mechanical behavior of soft tissue surrogates. The need to use techniques such as element erosion and re-meshing or to consider material failure is avoided by using a cylindrical target with a small pre-made cylindrical channel along its axis. Cavitation is excited by firing a spherical projectile through the pre-made channel whose diameter is smaller than that of the projectile. The transient response of the channel is recorded using a high speed camera and the images collected are analyzed using a digital image tracking software to measure the channel deformations. As an example to demonstrate the usefulness of the proposed experiment, measurements from a test involving a ballistic gelatin cylinder are used to evaluate the quality of numerical results produced by finite element analyses performed with ABAQUS/Explicit. The mechanical behavior of the soft tissue surrogate is represented in the simulations using a single-term Ogden model. Different values are attempted for the required material properties and friction coefficient based on data available in the literature and simple sensitivity studies. The experimental results are used to assess the results corresponding to each set of model parameters.

Imaging Features of Primary Tumors of the Hand

2020 ◽  
Vol 16 ◽  
Author(s):  
Filippo Boriani ◽  
Edoardo Raposio ◽  
Costantino Errani
Keyword(s):  
Soft Tissue ◽  
Soft Tissues ◽  
Epithelioid Sarcoma ◽  
Case Series ◽  
Malignant Neoplasm ◽  
Benign Tumors ◽  
Imaging Features ◽  
Primary Tumors ◽  
Therapeutic Decisions ◽  
Tumors Of The Hand

: Musculoskeletal tumors of the hand are a rare entity and are divided into skeletal and soft tissue tumors. Either category comprises benign and malignant or even intermediate tumors. Basic radiology allows an optimal resolution of bone and related soft tissue areas, ultrasound and more sophisticated radiologic tools such as scintigraphy, CT and MRI allow a more accurate evaluation of tumor extent. Enchondroma is the most common benign tumor affecting bone, whereas chondrosarcoma is the most commonly represented malignant neoplasm localized to hand bones. In the soft tissues ganglions are the most common benign tumors and epithelioid sarcoma is the most frequently represented malignant tumor targeting hand soft tissues. The knowledge regarding diagnostic and therapeutic management of these tumors is often deriving from small case series, retrospective studies or even case reports. Evidences from prospective studies or controlled trials are limited and for this lack of clear and supported evidences data from the medical literature on the topic are controversial, in terms of demographics, clinical presentation, diagnosis prognosis and therapy.The correct recognition of the specific subtype and extension of the tumor through first line and second line radiology is essential for the surgeon, in order to effectively direct the therapeutic decisions.

scholarly journals Developing a Quantifying Device for Soft Tissue Material Prop-Erties around Lumbar Spines

Biosensors ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 67
Author(s):  
Song Joo Lee ◽  
Yong-Eun Cho ◽  
Kyung-Hyun Kim ◽  
Deukhee Lee
Keyword(s):  
Lumbar Spine ◽  
Soft Tissue ◽  
Young’S Modulus ◽  
Viscoelastic Properties ◽  
Soft Tissues ◽  
Young's Modulus ◽  
Strain Curve ◽  
Stress And Strain ◽  
Commercial Device ◽  
Tissue Material

Knowing the material properties of the musculoskeletal soft tissue could be important to develop rehabilitation therapy and surgical procedures. However, there is a lack of devices and information on the viscoelastic properties of soft tissues around the lumbar spine. The goal of this study was to develop a portable quantifying device for providing strain and stress curves of muscles and ligaments around the lumbar spine at various stretching speeds. Each sample was conditioned and applied for 20 repeatable cyclic 5 mm stretch-and-relax trials in the direction and perpendicular direction of the fiber at 2, 3 and 5 mm/s. Our device successfully provided the stress and strain curve of the samples and our results showed that there were significant effects of speed on the young’s modulus of the samples (p < 0.05). Compared to the expensive commercial device, our lower-cost device provided comparable stress and strain curves of the sample. Based on our device and findings, various sizes of samples can be measured and viscoelastic properties of the soft tissues can be obtained. Our portable device and approach can help to investigate young’s modulus of musculoskeletal soft tissues conveniently, and can be a basis for developing a material testing device in a surgical room or various lab environments.

scholarly journals Quantification of assembly forces during creation of head-neck taper junction considering soft tissue bearing: a biomechanical study

Arthroplasty ◽  
2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Toni Wendler ◽  
Torsten Prietzel ◽  
Robert Möbius ◽  
Jean-Pierre Fischer ◽  
Andreas Roth ◽  
...  
Keyword(s):  
Soft Tissue ◽  
Work Experience ◽  
Soft Tissues ◽  
Force Sensor ◽  
Biomechanical Study ◽  
Measuring System ◽  
Wide Range ◽  
Head Neck

Abstract Background All current total hip arthroplasty (THA) systems are modular in design. Only during the operation femoral head and stem get connected by a Morse taper junction. The junction is realized by hammer blows from the surgeon. Decisive for the junction strength is the maximum force acting once in the direction of the neck axis, which is mainly influenced by the applied impulse and surrounding soft tissues. This leads to large differences in assembly forces between the surgeries. This study aimed to quantify the assembly forces of different surgeons under influence of surrounding soft tissue. Methods First, a measuring system, consisting of a prosthesis and a hammer, was developed. Both components are equipped with a piezoelectric force sensor. Initially, in situ experiments on human cadavers were carried out using this system in order to determine the actual assembly forces and to characterize the influence of human soft tissues. Afterwards, an in vitro model in the form of an artificial femur (Sawbones Europe AB, Malmo, Sweden) with implanted measuring stem embedded in gelatine was developed. The gelatine mixture was chosen in such a way that assembly forces applied to the model corresponded to those in situ. A study involving 31 surgeons was carried out on the aforementioned in vitro model, in which the assembly forces were determined. Results A model was developed, with the influence of human soft tissues being taken into account. The assembly forces measured on the in vitro model were, on average, 2037.2 N ± 724.9 N, ranging from 822.5 N to 3835.2 N. The comparison among the surgeons showed no significant differences in sex (P = 0.09), work experience (P = 0.71) and number of THAs performed per year (P = 0.69). Conclusions All measured assembly forces were below 4 kN, which is recommended in the literature. This could lead to increased corrosion following fretting in the head-neck interface. In addition, there was a very wide range of assembly forces among the surgeons, although other influencing factors such as different implant sizes or materials were not taken into account. To ensure optimal assembly force, the impaction should be standardized, e.g., by using an appropriate surgical instrument.

scholarly journals Imaging of Joint and Soft Tissue Involvement in Systemic Lupus Erythematosus

2021 ◽  
Vol 23 (9) ◽  
Author(s):  
Andrea Di Matteo ◽  
Gianluca Smerilli ◽  
Edoardo Cipolletta ◽  
Fausto Salaffi ◽  
Rossella De Angelis ◽  
...  
Keyword(s):  
Systemic Lupus Erythematosus ◽  
Soft Tissue ◽  
Lupus Erythematosus ◽  
Structural Damage ◽  
Structural Changes ◽  
Soft Tissues ◽  
Imaging Techniques ◽  
Joint Involvement ◽  
Systemic Lupus ◽  
Muscle Involvement

Abstract Purpose of Review To highlight the potential uses and applications of imaging in the assessment of the most common and relevant musculoskeletal (MSK) manifestations in systemic lupus erythematosus (SLE). Recent Findings Ultrasound (US) and magnetic resonance imaging (MRI) are accurate and sensitive in the assessment of inflammation and structural damage at the joint and soft tissue structures in patients with SLE. The US is particularly helpful for the detection of joint and/or tendon inflammation in patients with arthralgia but without clinical synovitis, and for the early identification of bone erosions. MRI plays a key role in the early diagnosis of osteonecrosis and in the assessment of muscle involvement (i.e., myositis and myopathy). Conventional radiography (CR) remains the traditional gold standard for the evaluation of structural damage in patients with joint involvement, and for the study of bone pathology. The diagnostic value of CR is affected by the poor sensitivity in demonstrating early structural changes at joint and soft tissue level. Computed tomography allows a detailed evaluation of bone damage. However, the inability to distinguish different soft tissues and the need for ionizing radiation limit its use to selected clinical circumstances. Nuclear imaging techniques are valuable resources in patients with suspected bone infection (i.e., osteomyelitis), especially when MRI is contraindicated. Finally, dual energy X-ray absorptiometry represents the imaging mainstay for the assessment and monitoring of bone status in patients with or at-risk of osteoporosis. Summary Imaging provides relevant and valuable information in the assessment of MSK involvement in SLE.

scholarly journals Micro-CT imaging of Thiel-embalmed and iodine-stained human temporal bone for 3D modeling

2021 ◽  
Vol 50 (1) ◽  
Author(s):  
Sebastian Halm ◽  
David Haberthür ◽  
Elisabeth Eppler ◽  
Valentin Djonov ◽  
Andreas Arnold
Keyword(s):  
Soft Tissue ◽  
Temporal Bone ◽  
Middle Ear ◽  
3D Modeling ◽  
Soft Tissues ◽  
Ct Imaging ◽  
Micro Ct ◽  
Data Set ◽  
Iodine Staining ◽  
Tissue Structures

Abstract Introduction This pilot study explores whether a human Thiel-embalmed temporal bone is suitable for generating an accurate and complete data set with micro-computed tomography (micro-CT) and whether solid iodine-staining improves visualization and facilitates segmentation of middle ear structures. Methods A temporal bone was used to verify the accuracy of the imaging by first digitally measuring the stapes on the tomography images and then physically under the microscope after removal from the temporal bone. All measurements were compared with literature values. The contralateral temporal bone was used to evaluate segmentation and three-dimensional (3D) modeling after iodine staining and micro-CT scanning. Results The digital and physical stapes measurements differed by 0.01–0.17 mm or 1–19%, respectively, but correlated well with the literature values. Soft tissue structures were visible in the unstained scan. However, iodine staining increased the contrast-to-noise ratio by a factor of 3.7 on average. The 3D model depicts all ossicles and soft tissue structures in detail, including the chorda tympani, which was not visible in the unstained scan. Conclusions Micro-CT imaging of a Thiel-embalmed temporal bone accurately represented the entire anatomy. Iodine staining considerably increased the contrast of soft tissues, simplified segmentation and enabled detailed 3D modeling of the middle ear.

Orthodontic Pre Grafting Closure of Large Alveolar Bony and Soft Tissue Gaps: A Novel Nonsurgical Protraction of the Lesser Segments in Growing Patients With Cleft Lip and Palate

2021 ◽  
pp. 105566562110076
Author(s):  
Maria Costanza Meazzini ◽  
Noah Cohen ◽  
Valeria Marinella Augusta Battista ◽  
Cristina Incorvati ◽  
Federico Biglioli ◽  
...  
Keyword(s):  
Soft Tissue ◽  
Surgical Procedures ◽  
Efficient Method ◽  
Bone Grafting ◽  
Cleft Lip ◽  
Soft Tissues ◽  
Cleft Lip And Palate ◽  
Face Mask ◽  
Younger Patients ◽  
Good Healing

Background: Closure of wide alveolar clefts with large soft tissue gaps and reconstruction of the dentoalveolar defect are challenging for the surgeon. Some authors successfully used interdental segmental distraction, which requires an additional surgical procedure. Objective: This study evaluates the effectiveness of tooth borne devices utilized to orthopedically advance the lesser segments, with a complete approximation of the soft tissue of the alveolar stumps, allowing traditional simultaneous soft tissue closure and bone grafting, and avoiding the need for supplementary surgery. Methods: Eight growing patients, 2 with unilateral complete cleft lip and palate (UCLP) and 6 with bilateral complete cleft lip and palate (BCLP), with large soft tissue and bony alveolar defects prior to bone grafting were prospectively selected. A banded rapid palatal expander (RPE) in BCLP and a modified RPE in UCLP combined with protraction face mask in younger patients or a modified Alt-Ramec in patients older than 12 years were applied. Radiographic and photographic records were available at T0, at the end of protraction (T1) and at least 1 year after bone grafting (T2). Results: Patients with large gaps showed a significant reduction in the bony cleft area and approximation of the soft tissues at T1. All patients received bone grafting with good healing and ossification at T2. Conclusion: In growing patients with UCLP and BCLP with large gaps, presurgical orthodontic protraction seems to be an efficient method to reduce the cleft defect, minimizing the risk of post grafting fistulas, reducing the need for supplementary surgical procedures.

scholarly journals Accuracy and Reliability of Soft Tissue Landmarks Using Three-Dimensional Imaging in Comparison With Two-Dimensional Cephalometrics: A Systematic Review

2020 ◽  
Vol 54 (4) ◽  
pp. 289-296
Author(s):  
Adeeba Ali ◽  
Anil K. Chandna ◽  
Anshul Munjal
Keyword(s):  
Systematic Review ◽  
Soft Tissue ◽  
3D Imaging ◽  
Soft Tissues ◽  
Three Dimensional ◽  
Database Search ◽  
Cochrane Library ◽  
Two Dimensional ◽  
Imaging Tool ◽  
Electronic Database Search

Background: Concerns about the accuracy and reliability of soft tissue landmarks using two-dimensional (2D) and three-dimensional (3D) imaging. Objective: The aim of the systematic review is to estimate accuracy and reliability of soft tissue landmarks with 2D imaging and 3D imaging for orthodontic diagnosis planning and treatment planning purposes. Data Sources: Electronic database search was performed in MEDLINE via PubMed, Embase via embase.com, and the Cochrane library website. Selection Criteria: The data were extracted according to two protocols based on Centre for Evidence-Based Medicine (CEBM) critical appraisal tools. Next, levels of evidence were categorized into three groups: low, medium, and high. Data Synthesis: Fifty-five publications were found through database search strategies. A total of nine publications were included in this review. Conclusion According to the available literature, 3D imaging modalities were more accurate and reliable as compared to 2D modalities. Cone beam computed tomography (CBCT) was considered the most reliable imaging tool for soft tissues.

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