scholarly journals Integration of Geometrical Boundary Conditions on Soft Tissue Characterization under large deformation

2008 ◽  
Author(s):  
Bummo Ahn ◽  
Jung Kim
Keyword(s):  
Soft Tissue ◽  
Boundary Conditions ◽  
Large Deformation ◽  
Tissue Characterization ◽  
Surface Deformation ◽  
Viscoelastic Model ◽  
Fe Modeling ◽  
Porcine Liver ◽  
Radius Of Influence ◽  
Geometrical Boundary

Soft tissue characterization with finite element (FE) modeling is important to develop a realistic model for medical simulation, since it is possible to display complex tool-tissue interactions during medical interventions. However, it is difficult to integrate large deformation and geometrical boundary conditions to the FE computations. In this paper, the force responses and surface deformation fields of the tissues against the indentation were measured by a force transducer and three-dimensional optical system. Large indentation experiments on porcine liver were performed to estimate the radius of influence from the indented point up to 8 mm indentation and to measure the force response for 7mm indentation. The radius of influence region was plotted against various indentation depths and indenter shapes, and it could be used to determine the model size for the characterization. The tissue behavior of large deformation considering influence of the boundary conditions was characterized with FE modeling via hyperelastic and linear viscoelastic model.

Complementary imaging of ultrasound and PET/CT: A new opportunity?

2021 ◽  
pp. 1-16
Author(s):  
Janine Rennert ◽  
Jirka Grosse ◽  
Ingo Einspieler ◽  
Wolf Bäumler ◽  
Christian Stroszczynski ◽  
...  
Keyword(s):  
High Resolution ◽  
Soft Tissue ◽  
Therapeutic Approach ◽  
Tissue Characterization ◽  
Tumor Detection ◽  
Tracer Uptake ◽  
Liver Lesions ◽  
Definite Diagnosis ◽  
Renal Lesions ◽  
Pet Ct

AIM: To evaluate the effectiveness of complementary imaging of high-resolution ultrasound including CEUS with PET/CT for tissue characterization and tumor detection. MATERIAL AND METHODS: 100 patients were examined with PET/CT and US/CEUS between January 2018 until February 2020. All patients underwent PET/CT followed by selective US/CEUS within 4 weeks. Comparison regarding concordant or diverging findings in PET/CT and US. Analysis of the differences concerning the lesions number of found by PET/CT and US/CEUS or the possibility of a secured diagnosis following ultrasound causing therapeutic changes. RESULTS: Diverging findings regarding the number of liver lesions in PET/CT and CEUS were found in 35 out of 64 patients (54%). Regarding renal lesions, a more definite diagnosis following ultrasound, causing a change of therapeutic approach, was achieved in 89%. Concordant results in PET/CT and US were found in 83%of patients with splenic and nodal findings. In 78%of patients with increased musculoskeletal or soft tissue tracer uptake, US was able to make a secured diagnosis with therapeutic changes. CONCLUSION: The present results indicate a strong benefit of complementary imaging of PET/CT and selective, high-resolution ultrasound especially in patients with liver, renal and musculoskeletal or soft tissue findings.

A NEW PARAMETER ESTIMATION METHOD FOR ONLINE SOFT TISSUE CHARACTERIZATION

2016 ◽  
Vol 16 (08) ◽  
pp. 1640019 ◽  
Author(s):  
JAEHYUN SHIN ◽  
YONGMIN ZHONG ◽  
JULIAN SMITH ◽  
CHENGFAN GU
Keyword(s):  
Soft Tissue ◽  
Linear Regression ◽  
Tissue Characterization ◽  
Soft Tissues ◽  
Unscented Kalman Filter ◽  
Estimation Method ◽  
Regression Method ◽  
Linear Regression Method ◽  
Non Linear

Dynamic soft tissue characterization is of importance to robotic-assisted minimally invasive surgery. The traditional linear regression method is unsuited to handle the non-linear Hunt–Crossley (HC) model and its linearization process involves a linearization error. This paper presents a new non-linear estimation method for dynamic characterization of mechanical properties of soft tissues. In order to deal with non-linear and dynamic conditions involved in soft tissue characterization, this method improves the non-linearity and dynamics of the HC model by treating parameter [Formula: see text] as independent variable. Based on this, an unscented Kalman filter is developed for online estimation of soft tissue parameters. Simulations and comparison analysis demonstrate that the proposed method is able to estimate mechanical parameters for both homogeneous tissues and heterogeneous and multi-layer tissues, and the achieved performance is much better than that of the linear regression method.

Preparation and Characteristics Analysis of PVA Hydrogel for Substituting Creatural Soft Tissue

2011 ◽  
Vol 52-54 ◽  
pp. 226-231
Author(s):  
Shan Jiang ◽  
Gong Cheng ◽  
Sha Liu ◽  
Wen Hao Feng ◽  
Zhen Zhang ◽  
...  
Keyword(s):  
Soft Tissue ◽  
Liver Tissue ◽  
Component Ratio ◽  
Porcine Liver ◽  
Surgical Technology ◽  
Important Relationship ◽  
Characteristics Analysis ◽  
Material Preparation ◽  
Test Result ◽  
Pva Hydrogel

Biopsy precious research has an important relationship with treatment efficiency and side effect complication. Most of the investigation is focus on the non-creatural material which is used to substitute creatural soft tissue for precious research. The aim of this paper is to develop a prescription that can be used for opaque and transparent PVA making which has similar mechanics property to the creatural tissue. The preparation, characteristics, and the results of PVA hydrogel on the composite material are studied as the key investigation. Porcine liver tissue property is also tested as a consultant for PVA material preparation. Comparing with the liver tissue test result, certain component ratio and freezing-thaw circle are determined. This PVA hydrogel material shows big potential in the creatural material substitution application. This research will benefit others who are interested in using non-creatural material to do experiment or surgical technology training.

Viscoelastic Characterization of Fiber-Reinforced Elastomeric Composites at Finite Strain

2010 ◽  
Vol 123-125 ◽  
pp. 603-606
Author(s):  
Mohammad Tahaye Abadi
Keyword(s):  
Constitutive Model ◽  
Large Deformation ◽  
Finite Strain ◽  
Mechanical Response ◽  
Viscoelastic Model ◽  
Constitutive Law ◽  
Micromechanical Modeling ◽  
Fiber Reinforced ◽  
Material Parameters ◽  
Elastomeric Composites

A viscoelastic model is developed to describe the mechanical response of fiber-reinforced elastomeric composites at large deformation. A continuum approach is used to model the macroscopic mechanical behavior of elastomeric materials reinforced with unidirectional fibers, in which the resin and fibers are regarded as a single homogenized anisotropic material. The anisotropic viscoelastic constitutive model is developed considering transient reversible network theory. An efficient computational algorithm based on micromechanical modeling is proposed to relate the material parameters of constitutive model to the mechanical properties of composite constituents at finite strain. The microstructure is identified by a representative volume element (RVE) and it is subjected to large deformation with considering the conformity of opposite boundaries. The material parameters of the viscoelastic constitutive law are determined based on the response of heterogeneous microstructure which is examined under different loading conditions.

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