scholarly journals Soft Tissue Artifact Compensation Using Triangular Cosserat Point Elements (TCPEs)

2017 ◽  
Author(s):  
Dana Solav ◽  
MB Rubin ◽  
Alon Wolf
Keyword(s):  
Soft Tissue ◽  
System Analysis ◽  
Breast Implant ◽  
Rigid Motion ◽  
Body Segment ◽  
Optoelectronic System ◽  
Data Set ◽  
Cosserat Point ◽  
Bony Segment ◽  
Soft Tissue Artifact

Existing methods which compensate for the Soft Tissue Artifact (STA) in optoelectronic motion measurements estimate the rigid motion of a nearly rigid underlying body segment based on analysis of the motion of all fiducial markers. The objective of the proposed Triangular Cosserat Point Elements (TCPE) method is to estimate the motion of the underlying body segment even when the STA in the entire cluster of markers can be large. This is accomplished by characterizing the cluster of markers with TCPEs defined by triangles based on all combinations of three markers. Then, scalar deformation measures characterizing the magnitudes of strain and relative rotation of pairs of TCPEs are defined for each TCPE. These deformation measures are used to define a filtered group of TCPEs which best represents the motion of the underlying body segment. The method was tested using an experimental setup that consists of a rigid pendulum with a deformable 300ml silicone breast implant attached to it as a simulation of the soft tissue around a bony segment. The rotation angles extracted from markers on the deformable implant were compared with simultaneous measurements of the rigid pendulum using an optoelectronic system. Analysis of the experimental data shows that this filtering process substantially reduces the error due to the STA even though the data set includes large deformations. In particular, the analysis shows that the error reduction using the TCPE approach is larger than the reductions obtained using standard least-squares minimization methods.

scholarly journals Bone Pose Estimation in the Presence of Soft Tissue Artifact Using Triangular Cosserat Point Elements

2015 ◽  
Vol 44 (4) ◽  
pp. 1181-1190 ◽  
Author(s):  
Dana Solav ◽  
M. B. Rubin ◽  
Andrea Cereatti ◽  
Valentina Camomilla ◽  
Alon Wolf
Keyword(s):  
Soft Tissue ◽  
Pose Estimation ◽  
Cosserat Point ◽  
Soft Tissue Artifact

scholarly journals Bone Pose Estimation in the Presence of Soft Tissue Artifact Using Triangular Cosserat Point Elements

2017 ◽  
Author(s):  
Dana Solav ◽  
MB Rubin ◽  
Andrea Cereatti ◽  
Valentina Camomilla ◽  
Alon Wolf
Keyword(s):  
Soft Tissue ◽  
Pose Estimation ◽  
Ex Vivo ◽  
Accurate Estimation ◽  
Relative Rotation ◽  
Kinematic Data ◽  
Cosserat Point ◽  
Position And Orientation ◽  
Soft Tissue Artifact ◽  
Procrustes Superimposition

Accurate estimation of the position and orientation (pose) of a bone from a cluster of skin markers is limited mostly by the relative motion between the bone and the markers, which is known as the Soft Tissue Artifact (STA). This work presents a method, based on continuum mechanics, to describe the kinematics of a cluster affected by STA. The cluster is characterized by Triangular Cosserat Point Elements (TCPEs) defined by all combinations of three markers. The effects of the STA on the TCPEs are quantified using three parameters describing the strain in each TCPE and the relative rotation and translation between TCPEs. The method was evaluated using previously collected ex-vivo kinematic data. Femur pose was estimated from 12 skin markers on the thigh, while its reference pose was measured using bone pins. Analysis revealed that instantaneous subsets of TCPEs exist which estimate bone position and orientation more accurately than the Procrustes Superimposition applied to the cluster of all markers. It has been shown that some of these parameters correlate well with femur pose errors, which suggests that they can be used to select, at each instant, subsets of TCPEs leading an improved estimation of the underlying bone pose.

scholarly journals Validation method for body-mounted sensor attachments

2020 ◽  
Vol 6 (2) ◽  
Author(s):  
Katharina Schmidt ◽  
David Hochmann
Keyword(s):  
Evaluation Method ◽  
Tracking System ◽  
The Body ◽  
Exploratory Research ◽  
Body Segment ◽  
Validation Method ◽  
Sensor Position ◽  
Validation Parameters ◽  
Measurement Units ◽  
Soft Tissue Artifact

AbstractSmall sensor devices like inertial measurement units enable mobile movement and gait analysis, whereby existing systems differ in data acquisition, data processing, and gait parameter calculation. Concerning the validation, recent studies focus on the captured motion and the influence of sensor positioning with respect to the accuracy of the computed biomechanical parameters in comparison to a reference system. Although soft tissue artifact is a major source of error for skin-mounted sensors, there are no investigations regarding the relative movement between the body segment and sensor attachment itself. The aim of this study is to find an evaluation method and to determine parameters that allow the validation of various sensor attachment types and different sensor positionings. The analysis includes the comparison between an adhesive and strap attachment variant as well as the frontal and lateral sensor placement. To validate different attachments, an optical marker-based tracking system was used to measure the body segment and sensor position during movement. The distance between these two positions was calculated and analyzed to determine suitable validation parameters. Despite the exploratory research, the results suggest a feasible validation method to detect differences between the attachments, independent of the sensor type. To have representative and statistically validated results, further studies that involve more participants are necessary.

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.

scholarly journals An automated system analysis and design tool for spacecrafts ceas space journal

2021 ◽  
Author(s):  
Manfred Ehresmann ◽  
Georg Herdrich ◽  
Stefanos Fasoulas
Keyword(s):  
Evolutionary Algorithms ◽  
Evolutionary Algorithm ◽  
Degrees Of Freedom ◽  
System Analysis ◽  
Propulsion System ◽  
Optimal System ◽  
Automated System ◽  
Processing Unit ◽  
Data Set ◽  
Analysis And Design

AbstractIn this paper, a generic full-system estimation software tool is introduced and applied to a data set of actual flight missions to derive a heuristic for system composition for mass and power ratios of considered sub-systems. The capability of evolutionary algorithms to analyse and effectively design spacecraft (sub-)systems is shown. After deriving top-level estimates for each spacecraft sub-system based on heuristic heritage data, a detailed component-based system analysis follows. Various degrees of freedom exist for a hardware-based sub-system design; these are to be resolved via an evolutionary algorithm to determine an optimal system configuration. A propulsion system implementation for a small satellite test case will serve as a reference example of the implemented algorithm application. The propulsion system includes thruster, power processing unit, tank, propellant and general power supply system masses and power consumptions. Relevant performance parameters such as desired thrust, effective exhaust velocity, utilised propellant, and the propulsion type are considered as degrees of freedom. An evolutionary algorithm is applied to the propulsion system scaling model to demonstrate that such evolutionary algorithms are capable of bypassing complex multidimensional design optimisation problems. An evolutionary algorithm is an algorithm that uses a heuristic to change input parameters and a defined selection criterion (e.g., mass fraction of the system) on an optimisation function to refine solutions successively. With sufficient generations and, thereby, iterations of design points, local optima are determined. Using mitigation methods and a sufficient number of seed points, a global optimal system configurations can be found.

Nodular Fasciitis: Differential Considerations and Current Management Strategies

2009 ◽  
Vol 75 (7) ◽  
pp. 610-614 ◽  
Author(s):  
Stephen R. Grobmyer ◽  
Jacquelyn A. Knapik ◽  
Robin M. Foss ◽  
Edward M. Copeland ◽  
Steven N. Hochwald
Keyword(s):  
Soft Tissue ◽  
Soft Tissue Sarcoma ◽  
Breast Implant ◽  
Correct Diagnosis ◽  
Recent Experience ◽  
Nodular Fasciitis ◽  
Tissue Mass ◽  
Complete Excision ◽  
Soft Tissue Sarcoma Patient ◽  
Imaging Characteristics

Nodular fasciitis (NF) typically presents as an enlarging soft tissue mass with imaging characteristics that may be suggestive of soft tissue sarcoma or desmoid tumor. This presentation can make a correct diagnosis and management of patients with NF a challenge. We report our recent experience with two cases of NF that were both referred with a diagnoses of “soft tissue sarcoma.” Patient 1 was a 46-year-old woman who had undergone breast augmentation and was referred with a rapidly growing firm mass on the left chest wall beneath the breast implant. Computed tomography of the chest noted the mass to be 8 cm X 11 cm in size displacing the implant laterally with no radiological involvement of the bony structures of the chest. Core biopsy was suggestive of inflammation only. Given the clinical suspicion of malignancy, the patient underwent resection of the mass with implant removal. Final pathology showed NF. Patient 2 was a 65-year-old woman referred with an enlarging tender 3-cm infraclavicular mass and a clinical diagnosis of “soft tissue sarcoma.” Preoperative biopsy suggested NF. The patient underwent complete excision, which confirmed the diagnosis. These cases highlight the clinical issues associated with management of patients with NF. Current approaches to evaluation, diagnosis, and treatment of NF are discussed.

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