A New Subject-Specific Skin Correction Factor for Three-Dimensional Kinematic Analysis of the Scapula

2009 ◽  
Vol 131 (12) ◽  
Author(s):  
Douglas A. Bourne ◽  
Anthony M. Choo ◽  
William D. Regan ◽  
Donna L. MacIntyre ◽  
Thomas R. Oxland
Keyword(s):  
Correction Factor ◽  
Gold Standard ◽  
Three Dimensional ◽  
Skin Surface ◽  
Surface Markers ◽  
Correction Factors ◽  
Scapular Kinematics ◽  
Bony Landmarks ◽  
Subject Specific ◽  
Rms Errors

Noninvasive measurement of scapular kinematics using skin surface markers presents technical challenges due to the relative movement between the scapula and the overlying skin. The objectives of this study were to develop a noninvasive subject-specific skin correction factor that would enable a more accurate measurement of scapular kinematics and evaluate this new technique via comparison with a gold standard for scapular movement. Scapular kinematics were directly measured using bone pins instrumented with optoelectronic marker carriers in eight healthy volunteers while skin motion was measured simultaneously with optoelectronic markers attached to the skin surface overlying the scapula. The relative motion between the skin markers and the underlying scapula was estimated over a range of humeral orientations by palpating and digitizing bony landmarks on the scapula and then used to calculate correction factors that were weighted by humeral orientation. The scapular kinematics using these correction factors were compared with the kinematics measured via the bone pins during four arm movements in the volunteers: abduction, forward reaching, hand behind back, and horizontal adduction. The root-mean-square (rms) errors for the kinematics determined from skin markers without the skin correction factors ranged from 5.1 deg to 9.5 deg while the rms errors with the skin correction factors ranged from 1.4 deg to 3.0 deg. This technique appeared to perform well for different movements and could possibly be extended to other applications.

The Placement of Skin Surface Markers for Non-Invasive Measurement of Scapular Kinematics Affects Accuracy and Reliability

2010 ◽  
Vol 39 (2) ◽  
pp. 777-785 ◽  
Author(s):  
Douglas A. Bourne ◽  
Anthony M. Choo ◽  
William D. Regan ◽  
Donna L. MacIntyre ◽  
Thomas R. Oxland
Keyword(s):  
Skin Surface ◽  
Surface Markers ◽  
Scapular Kinematics ◽  
Non Invasive ◽  
Invasive Measurement

On Shear Correction Factor in Vibration of Annular Sector Plates

2010 ◽  
Author(s):  
F. Hejripour ◽  
A. R. Saidi ◽  
S. H. Mirtalaie
Keyword(s):  
Boundary Conditions ◽  
Elasticity Theory ◽  
Correction Factor ◽  
Three Dimensional ◽  
Mode Shapes ◽  
Correction Factors ◽  
Asymmetric Mode ◽  
Shear Correction Factor ◽  
Annular Sector ◽  
Three Dimensional Elasticity

In the present study, the shear correction factors are obtained for annular sector plates using Differential Quadrature (DQ) Method. Based on the three-dimensional elasticity theory, the governing equations of motion for an annular sector plate are obtained. These equations together with the boundary conditions are discretized by employing DQ method. Following DQ procedure an eigenvalue problem is obtained that represents the natural frequencies and mode shapes of the plate. This procedure is also investigated for the analysis of the annular sector plates based on FSDT. The frequency of the first asymmetric mode of thickness direction for various shear correction factors are compared with the results of the three-dimensional elasticity theory. Therefore, the appropriate shear correction factor can be found. Some shear correction factors are obtained for various boundary conditions. It is shown that the value of the shear correction factor depends on the plate geometry and the boundary conditions.

Relationships between Spinal Landmarks and Skin Surface Markers

2008 ◽  
Vol 24 (1) ◽  
pp. 94-97 ◽  
Author(s):  
Jack R. Engsberg ◽  
Lawrence G. Lenke ◽  
Keith H. Bridwell ◽  
Mary L. Uhrich ◽  
Connie M. Trout
Keyword(s):  
Skin Surface ◽  
Surface Marker ◽  
Metallic Surface ◽  
Surface Markers ◽  
Vertical Alignment ◽  
X Ray ◽  
Marker Data ◽  
Bony Landmarks ◽  
Biplanar Radiographs

This investigation determined relationships between coronal vertical alignment (CVA) and sagittal vertical alignment (SVA) variables calculated from radiographs and surface markers representing bony landmarks. Biplanar radiographs were taken on 28 subjects (standing) after 2 metallic surface markers were placed on the skin superficial to C7 and S2. The CVA-R and SVA-R were measured on the radiographs. Similar variables were calculated from the surface markers (CVA-P-R, SVA-P-R). Correlation between CVA-R and CVA-P-R was 0.894 (p < 0.000), and between SVA-R and SVA-P-R was 0.946 (p < 0.000). Results lead to three recommendations: (1) obtain surface marker data when radiographs are taken to establish relationships between the two sets of data, (2) take care in providing instructions to the subjects if measures are to be taken at different times, and (3) observe caution in interpreting results when simultaneous x-ray and surface marker data were not recorded.

scholarly journals Application of subject-specific adaptive mechanical loading for bone healing in a mouse tail vertebral defect

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Angad Malhotra ◽  
Matthias Walle ◽  
Graeme R. Paul ◽  
Gisela A. Kuhn ◽  
Ralph Müller
Keyword(s):  
Mechanical Loading ◽  
Bone Defect ◽  
Bone Healing ◽  
Three Dimensional ◽  
Patient Specific ◽  
Dependent Manner ◽  
Micro Computed Tomography ◽  
Computed Tomography Images ◽  
Bone Defect Healing ◽  
Subject Specific

AbstractMethods to repair bone defects arising from trauma, resection, or disease, continue to be sought after. Cyclic mechanical loading is well established to influence bone (re)modelling activity, in which bone formation and resorption are correlated to micro-scale strain. Based on this, the application of mechanical stimulation across a bone defect could improve healing. However, if ignoring the mechanical integrity of defected bone, loading regimes have a high potential to either cause damage or be ineffective. This study explores real-time finite element (rtFE) methods that use three-dimensional structural analyses from micro-computed tomography images to estimate effective peak cyclic loads in a subject-specific and time-dependent manner. It demonstrates the concept in a cyclically loaded mouse caudal vertebral bone defect model. Using rtFE analysis combined with adaptive mechanical loading, mouse bone healing was significantly improved over non-loaded controls, with no incidence of vertebral fractures. Such rtFE-driven adaptive loading regimes demonstrated here could be relevant to clinical bone defect healing scenarios, where mechanical loading can become patient-specific and more efficacious. This is achieved by accounting for initial bone defect conditions and spatio-temporal healing, both being factors that are always unique to the patient.

scholarly journals Scientific validation of three-dimensional stereophotogrammetry compared to the IGAIS clinical scale for assessing wrinkles and scars after laser treatment

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Barbara Helena Barcaro Machado ◽  
Ivy Dantas De Melo E. Silva ◽  
Walter Marou Pautrat ◽  
James Frame ◽  
Mohammad Najlah
Keyword(s):  
Laser Treatment ◽  
Three Dimensional ◽  
Skin Surface ◽  
Clinical Scale ◽  
3D Images ◽  
Laser Resurfacing ◽  
Before And After ◽  
Measuring Outcomes ◽  
Skin Scar ◽  
Scientific Validation

AbstractMeasuring outcomes from treatments to the skin is either reliant upon patient’s subjective feedback or scale-based peer assessments. Three-Dimensional stereophotogrammetry intend to accurately quantify skin microtopography before and after treatments. The objective of this study is comparing the accuracy of stereophotogrammetry with a scale-based peer evaluation in assessing topographical changes to skin surface following laser treatment. A 3D stereophotogrammetry system photographed skin surface of 48 patients with facial wrinkles or scars before and three months after laser resurfacing, followed immediately by topical application of vitamin C. The software measured changes in skin roughness, wrinkle depth and scar volume. Images were presented to three observers, each independently scoring cutaneous improvement according to Investigator Global Aesthetic Improvement Scale (IGAIS). As for the results, a trend reflecting skin/scar improvement was reported by 3D SPM measurements and raters. The percentage of topographical change given by the raters matched 3D SPM findings. Agreement was highest when observers analysed 3D images. However, observers overestimated skin improvement in a nontreatment control whilst 3D SPM was precise in detecting absence of intervention. This study confirmed a direct correlation between the IGAIS clinical scale and 3D SPM and confirmed the efficacy and accuracy of the latter when assessing cutaneous microtopography alterations as a response to laser treatment.

scholarly journals Effect of aerosol composition on the performance of low-cost optical particle counter correction factors

2019 ◽  
Author(s):  
Leigh R. Crilley ◽  
Ajit Singh ◽  
Louisa J. Kramer ◽  
Marvin D. Shaw ◽  
Mohammed S. Alam ◽  
...  
Keyword(s):  
Correction Factor ◽  
Low Cost ◽  
Particle Mass ◽  
Ambient Atmosphere ◽  
Correction Factors ◽  
Aerosol Composition ◽  
Kohler Theory ◽  
Suitable Reference ◽  
Aerosol Hygroscopicity ◽  
Mass Concentrations

Abstract. There is considerable interest in using low-cost optical particle counters (OPC) to supplement existing routine air quality networks that monitor particle mass concentrations. In order to do this, low-cost OPC data needs to be cross-comparable with particle mass reference instrumentation, and as yet, there is no widely agreed methodology. Aerosol hygroscopicity is known to be a key parameter to consider when correcting particle mass concentrations derived from a low-cost OPC, particularly at high ambient Relative Humidity (RH). Correction factors have been developed that apply κ-Köhler theory to correct for the influence of water uptake by hygroscopic aerosols. We have used datasets of co-located reference particle measurements and a low-cost OPC (OPC-N2, Alphasense), collected in four cities in three continents, to explore the performance of this correction factor. We report evidence that the elevated particle mass concentrations, reported by the low-cost OPC relative to reference instrumentation, is due to bulk aerosol hygroscopicity under different RH conditions, which is determined by aerosol composition and in particular the levels of hygroscopic aerosols (sulphate and nitrate). We exploit measurements made in volcanic plumes in Nicaragua, that are predominantly composed of sulphate aerosol, as a natural experiment to demonstrate this behaviour in the ambient atmosphere, with the observed humidogram closely resembling the calculated pure sulphuric acid humidogram. The results indicate that the particle mass concentrations derived from low-cost OPCs during periods of high RH (> 60 %) need to be corrected for aerosol hygroscopic growth. We employed a correction factor based on κ-Köhler theory and observed corrected OPC-N2 PM2.5 mass concentrations to be within 33 % of reference measurements at all sites. The results indicated that an in situ derived κ (using suitable reference instrumentation) would lead to the most accurate correction relative to co-located reference instruments. Applying literature κ in the correction factor also resulted in improved performance of OPC-N2, to be within 50 % of reference. Therefore, for areas where suitable reference instrumentation for developing a local correction factor is lacking, using a literature κ value can result in a reasonable correction. For locations with low levels of hygroscopic aerosols and RH, a simple calibration against gravimetric measurements (using suitable reference instrumentation) would likely be sufficient. Whilst this study generated correction factors specific for the Alphasense OPC-N2 sensor, the calibration methodology developed is likely amenable to other low cost PM sensors.

scholarly journals Striatal Dopamine Transporter Spect Quantification: Head-To-Head Comparison Between Two Three-Dimensional Automatic Tools

2020 ◽  
Author(s):  
Silvia Morbelli ◽  
Dario Arnaldi ◽  
Eugenia Cella ◽  
Stefano Raffa ◽  
Isabella Donegani ◽  
...  
Keyword(s):  
Dopamine Transporter ◽  
Gold Standard ◽  
Rating Scale ◽  
Three Dimensional ◽  
Correlation Coefficients ◽  
Striatal Dopamine ◽  
Dat Spect ◽  
Disease Rating ◽  
Highly Correlated ◽  
Visual Reading

Abstract Purpose. Our aim was the head-to-head comparison between two automatic tools for semi-quantification of striatal dopamine transporter (DAT) specific-to-non displaceable (SBR) ratio brain SPECT values in a naturalistic cohort of patients. Procedures. We analyzed consecutive scans from one-hundred and fifty-one outpatients submitted to brain DAT SPECT for a suspected parkinsonism. Images were post-processed using a commercial (Datquant®) and a free (BasGanV2) software. Reading by expert was the gold-standard. A subset of patients with pathological or borderline scan was evaluated with the clinical Unified Parkinson’s disease rating scale, motor part (MDS-UPDRS-III). Results. SBR, putamen-to-caudate (P/C) ratio, and both P and C asymmetries were highly correlated between the two software with Pearson’s ‘r’ correlation coefficients ranging from .706 to .887. Correlation coefficients with the MDS-UPDRS III score were higher with caudate than with putamen SBR values with both software, and in general higher with BasGanV2 than with Datquant® . Datquant® correspondence with expert reading was 84.1% (94.0% by additionally considering the P/C ratio as a further index). BasGanV2 correspondence with expert reading was 80.8% (86.1% by additionally considering the P/C ratio). Conclusions. Both Datquant® and BasGanV2 work reasonably well and similarly one another in semi-quantification of DAT SPECT. Both tools have their own strength and pitfalls that must be known in detail by users in order to obtain the best help in visual reading and reporting of DAT SPECT.

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