scholarly journals Influence of Examiners’ Experience and Region of Interest Location on Semiquantitative Elastography Validity and Reliability

2021 ◽  
Vol 11 (19) ◽  
pp. 9247
Author(s):  
Juan Antonio Valera-Calero ◽  
César Fernández-de-las-Peñas ◽  
Tomás Fernández-Rodríguez ◽  
José Luis Arias-Buría ◽  
Umut Varol ◽  
...  
Keyword(s):  
Imaging Technique ◽  
Central Area ◽  
Region Of Interest ◽  
Absolute Error ◽  
Tissue Stiffness ◽  
Validity And Reliability ◽  
Small Magnitude ◽  
Accuracy Study ◽  
Semiquantitative Elastography ◽  
Determinant Factor

Semi-quantitative elastography is a promising imaging technique to evaluate tissue stiffness differences, providing data regarding relative stiffness differences between two targets. The aims of this study were to assess the validity, inter-examiner reliability and variability of semi-quantitative elastography for calculating strain ratios (SR) in a homogeneous gel phantom in different locations within the image. A diagnostic accuracy study was performed in a homogeneous stiffness phantom. Four examiners participated (two novice and two experienced). Each examiner assessed the SR in two locations. Difference between examiners, variability of measurements, SR error and absolute error, mean error of the measurements and coefficient of variation were calculated. The agreement between examiners, validity and variability of measurements were higher in the central area than the lateral areas of the images. Thus, the experience of the examiner was relevant for the concordance of the measurements in the lateral areas of the images (SR difference of 0.14 ± 0.05; p < 0.001), but not for the central area (SR difference of 0.05 ± 0.02; p > 0.05). Our data suggested that semi-quantitative elastography is an accurate tool for assessing small magnitude stiffness differences within the same image in central areas, but the experience of the examiner is a determinant factor.

scholarly journals How Accurate Is Semi-quantitative Elastography for Calculating Strain Ratios? A Validity and Reliability Study

2021 ◽  
Author(s):  
Juan Antonio Valera-Calero ◽  
César Fernández-de-las-Peñas ◽  
Tomás Fernández-Rodríguez ◽  
José Luis Arias-Buría ◽  
Gracia María Gallego-Sendarrubias ◽  
...  
Keyword(s):  
Acoustic Radiation ◽  
Imaging Technique ◽  
Pulse Sequences ◽  
Central Area ◽  
Radiation Force ◽  
Absolute Error ◽  
Validity And Reliability ◽  
Musculoskeletal Tissues ◽  
Accuracy Study

Abstract Background: Elastography is a promising imaging technique for evaluating various musculoskeletal tissues which uses acoustic radiation force pulse sequences to generate shear waves, which propagate perpendicular to the ultrasound beam causing transient displacements to calculate the tissues stiffness. Objective: The aims were to assess the validity, inter-examiner reliability and stability of semi-quantitative elastography for calculating strain ratios (SR) in a homogeneous gel phantom in different locations within the image. Methods: A diagnostic accuracy study was performed in a homogeneous stiffness phantom. Two examiners (one novice and one experienced) performed 50 imaging captures in 5 series of 10 captures with 1-minute difference between captures and 30 minutes difference be-tween series. Each examiner assessed the SR in two locations. Difference between-examiners, stability of measurements, SR error and absolute error, mean error of the measurements and coefficient of variation were calculated. Results: The agreement between examiners, validity and stability of measurements were higher in the central area than the lateral limits of the images. Thus, the experience of the examiner showed to be relevant for the concordance of the measurements in the lateral limits of the images (SR difference of 0.13 ± 0.02; p<0.001), but not for the central area (SR difference of 0.00 ± 0.01; p>0.05). Conclusion: Semi-quantitative elastography seems to be an accurate tool for assessing stiffness differences within the same image. Further validity and reliability studies in different materials and in-vivo tissues are needed to ensure the utility of this method.

Invariance of Wearing Location of Omron-BI Pedometers: A Validation Study

2010 ◽  
Vol 7 (6) ◽  
pp. 706-717 ◽  
Author(s):  
Weimo Zhu ◽  
Miyoung Lee
Keyword(s):  
Validation Study ◽  
Absolute Error ◽  
Activity Monitor ◽  
Error Rates ◽  
Living Conditions ◽  
The Body ◽  
Validity And Reliability ◽  
Free Living ◽  
Climbing Stairs ◽  
Free Living Conditions

Background:The purpose of this study was to investigate the validity and reliability evidences of the Omron BI pedometer, which could count steps taken even when worn at different locations on the body.Methods:Forty (20 males and 20 females) adults were recruited to walk wearing 5 sets, 1 set at a time, of 10 BI pedometers during testing, 1 each at 10 different locations. For comparison, they also wore 2 Yamax Digi-Walker SW-200 pedometers and a Dynastream AMP 331 activity monitor. The subjects walked in 3 free-living conditions: a fat sidewalk, stairs, and mixed conditions.Results:Except for a slight decrease in accuracy in the pant pocket locations, Omron BI pedometers counted steps accurately across other locations when subjects walked on the fat sidewalk, and the performance was consistent across devices and trials. When the subjects climbed up stairs, however, the absolute error % of the pant pocket locations increased significantly (P < .05) and similar or higher error rates were found in the AMP 331 and SW-200s.Conclusions:The Omron BI pedometer can accurately count steps when worn at various locations on the body in free-living conditions except for front pant pocket locations, especially when climbing stairs.

A Research of Electromagnetic Tomography Based on Different Parameters

2013 ◽  
Vol 834-836 ◽  
pp. 926-929
Author(s):  
Jing Sun ◽  
Fun Qun Shao
Keyword(s):  
Electromagnetic Induction ◽  
Imaging Technique ◽  
Region Of Interest ◽  
Industrial Applications ◽  
Projection Data ◽  
Conducting Material ◽  
Electromagnetic Tomography ◽  
Electrically Conducting ◽  
Fundamental Investigation ◽  
Electromagnetic Measurements

Electromagnetic tomography (EMT) is a recent imaging technique. Its purpose is to determine the distribution of electrical conductivity and magnetic permeability in a given region of interest. EMT is based on the principle of electromagnetic induction. This distribution is computed from the measurements of the induced voltages at several coils placed around the region which are produced by the application of different excitation patterns . Usually images are obtained through inversion of the projection data. The paper represents a fundamental investigation of the potential of using electromagnetic measurements for industrial tomography application. This paper concentrates on image reconstruction of either electrically conducting material or magnetically permeable materials. Finally a number of potential industrial applications for the EMT technique are discussed.

scholarly journals A Comparison of Hyper-Reflective Retinal Spot Counts in Optical Coherence Tomography Images from Glaucomatous and Healthy Eyes

2021 ◽  
Vol 10 (20) ◽  
pp. 4668
Author(s):  
Luciano Quaranta ◽  
Carlo Bruttini ◽  
Giovanni De Angelis ◽  
Silvia Montescani ◽  
Alberto Ardizzone ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Open Angle Glaucoma ◽  
Central Area ◽  
Region Of Interest ◽  
Mean Deviation ◽  
Healthy Controls ◽  
Optical Coherence ◽  
Foveal Thickness ◽  
Average Value ◽  
The One

Purpose: To compare the number of hyper-reflective retinal spots (HRS) in optical coherence tomography (OCT) images of healthy controls and patients affected with primary open angle glaucoma (POAG). Methods: Thirty patients affected with POAG and 34 healthy controls were recruited and underwent raster OCT examination of the macular region. Among the acquired B-scans, the one with the lowest foveal thickness was selected, and a central area of 3000 μm was defined (region of interest, ROI), in order to identify HRS. HRS were defined as small point-like hyper-reflective elements, detectable at the visual inspection of the OCT image. HRS were independently counted by two investigators in the ROI of each OCT scan. Results: Inter-rater agreement for HRS counting was good to excellent (ICC = 0.96, 95% CI: 0.83–0.99). More HRS were found in the OCT images from glaucoma patients, in comparison with healthy controls (average value: 90.5 ± 13.02 and 74.72 ± 11.35, for glaucoma and healthy subjects, respectively; p < 0.01). Significant correlations between the average number of HRS and visual field mean deviation (MD, p = 0.01) and pattern standard deviation (PSD, p < 0.01) were found. Conclusions: OCT images from glaucoma patients showed a higher number of HRS when compared with healthy controls. As HRS have been hypothesized to be a sign of neuroinflammation, these results may support the role of neuroinflammation in glaucoma etiopathogenesis.

scholarly journals Reliability and Validity of the Disloyalty in the Workplace Scale

2019 ◽  
Vol 8 (6) ◽  
pp. 100
Author(s):  
Hüseyin Aslan ◽  
Cevat Elma ◽  
Yüksel Gündüz
Keyword(s):  
Factor Analysis ◽  
Confirmatory Factor Analysis ◽  
Reliability Analysis ◽  
Central Area ◽  
Reliability And Validity ◽  
Validity And Reliability ◽  
Related Factors ◽  
Analysis Process ◽  
Confirmatory Factor ◽  
Data Collection Instrument

The aim of this study is to develop a valid and reliable scale, which measures disloyalty in the workplace. The population of the study consisted of teachers working in the central area of Samsun in Turkey during 2017-2018 academic year. 742 teachers, who volunteered to take part in the study, constituted the sample of the study, and they were selected randomly. In data analysis process, exploratory factor analysis, confirmatory factor analysis and reliability analysis were used.  According to the results of explanatory factor analysis, the scale was composed of 21 items and 2 sub-scales called manager disloyalty and colleague disloyalty and these two sub-dimensions have been explaining .86.7 of total variance. According to the results of confirmatory factor analysis, all items constituted a meaningful structure under related factors and factor loadings of all items were above .30. As for the reliability analysis, Cronbach Alfa, Guttman and Spearman Brown analyses were carried out and Cronbach Alfa coefficient of total points of the scale was found as .99; the Guttman coefficient was found as .89 and Spearman Brown coefficient was found as .89. This scale of which validity and reliability analysis were completed in this study can be used by researchers studying on disloyalty in the workplace as a data collection instrument. 

scholarly journals Camera-based heart rate estimation for hospitalized newborns in the presence of motion artifacts

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Qiong Chen ◽  
Yalin Wang ◽  
Xiangyu Liu ◽  
Xi Long ◽  
Bin Yin ◽  
...  
Keyword(s):  
Heart Rate ◽  
Body Movement ◽  
Region Of Interest ◽  
Ground Truth ◽  
Absolute Error ◽  
Motion Artifact ◽  
Motion Artifacts ◽  
Majority Voting ◽  
Thermal Cameras ◽  
Electrocardiogram Ecg

Abstract Background Heart rate (HR) is an important vital sign for evaluating the physiological condition of a newborn infant. Recently, for measuring HR, novel RGB camera-based non-contact techniques have demonstrated their specific superiority compared with other techniques, such as dopplers and thermal cameras. However, they still suffered poor robustness in infants’ HR measurements due to frequent body movement. Methods This paper introduces a framework to improve the robustness of infants’ HR measurements by solving motion artifact problems. Our solution is based on the following steps: morphology-based filtering, region-of-interest (ROI) dividing, Eulerian video magnification and majority voting. In particular, ROI dividing improves ROI information utilization. The majority voting scheme improves the statistical robustness by choosing the HR with the highest probability. Additionally, we determined the dividing parameter that leads to the most accurate HR measurements. In order to examine the performance of the proposed method, we collected 4 hours of videos and recorded the corresponding electrocardiogram (ECG) of 9 hospitalized neonates under two different conditions—rest still and visible movements. Results Experimental results indicate a promising performance: the mean absolute error during rest still and visible movements are 3.39 beats per minute (BPM) and 4.34 BPM, respectively, which improves at least 2.00 and 1.88 BPM compared with previous works. The Bland-Altman plots also show the remarkable consistency of our results and the HR derived from the ground-truth ECG. Conclusions To the best of our knowledge, this is the first study aimed at improving the robustness of neonatal HR measurement under motion artifacts using an RGB camera. The preliminary results have shown the promising prospects of the proposed method, which hopefully reduce neonatal mortality in hospitals.

scholarly journals Vision-based pose estimation of craniocervical region: experimental setup and saw bone-based study

Robotica ◽  
2021 ◽  
pp. 1-16
Author(s):  
Mohammad Zubair ◽  
Sachin Kansal ◽  
Sudipto Mukherjee
Keyword(s):  
Pose Estimation ◽  
Spinal Column ◽  
Region Of Interest ◽  
Preliminary Test ◽  
Absolute Error ◽  
Craniovertebral Junction ◽  
Human Motion ◽  
Percentage Error ◽  
The Absolute ◽  
Implant Testing

Summary This article discusses the intervertebral motion present in the craniovertebral junction (CVJ) region. The CVJ region is bounded by the first three vertebras from the spinal column. It helps in bringing most of the neck motion. Intervention in this region requires surgery in which an implant is placed to stabilize the whole system. The various available implants need to undergo performance evaluation as their performance varies from region and anatomical diversity. For the Indian population, we are targeting to evaluate the performance of such an implant, testing it into a cadaver. The region of interest will be loaded as per the loading condition of an average human. Motion in these regions is evaluated using the camera. A preliminary test was done on a saw bone model of CVJ to assess the performance of segmentation methods. Multiple such ArUco markers are used to increase pose accuracy further, and the pose of the entire board of multiple tags provides us with reliable pose estimation. The absolute error ranged from a minimum of 0.1 mm to a maximum of 16 mm. At the same time, the mean and median absolute errors were 3.8961 mm and 3.35 mm. By considering the absolute lengths, the percentage error showed the following trends. The percentage error was between 3.9168% and 0.0230%.

Longitudinal assessment of quantitative ultra-widefield ischaemic and vascular parameters in sickle cell retinopathy

2020 ◽  
pp. bjophthalmol-2020-317241
Author(s):  
Duriye Damla Sevgi ◽  
Adrienne W Scott ◽  
Alison Martin ◽  
Christopher Mugnaini ◽  
Shaivi Patel ◽  
...  
Keyword(s):  
Sickle Cell ◽  
Geodesic Distance ◽  
Region Of Interest ◽  
Rate Of Change ◽  
Linear Mixed Effect Model ◽  
Time Interval ◽  
Longitudinal Assessment ◽  
Mixed Effect ◽  
Small Magnitude ◽  
Vessel Area

PurposeTo evaluate longitudinal quantitative ischaemic and vasculature parameters, including ischaemic index, vessel area, length and geodesic distance in sickle cell retinopathy (SCR) on ultra-widefield fluorescein angiography (UWFA).MethodsOptimal UWFA images from two longitudinal timepoints of 74 eyes from 45 patients with SCR were aligned and a common region of interest was determined. A deep-learning augmented ischaemia and vascular segmentation platform was used for feature extraction. Geodesic distance maps demonstrating the shortest distance within the vascular masks from the centre of the optic disc were created. Ischaemic index, vessel area, vessel length and geodesic distance were measured. Paired t-test and linear mixed effect model analysis were performed.ResultsOverall, 25 (44 eyes) patients with HbSS, 14 (19 eyes) with HbSC, 6 (11 eyes) with HbSthal and other genotypes were included. Mean age was 40.1±11.0 years. Mean time interval between two UWFA studies was 23.0±15.1 months (range: 3–71.3). Mean panretinal ischaemic index increased from 10.0±7.2% to 10.9±7.3% (p<0.005). Mean rate of change in ischaemic index was 0.5±0.7% per year. Mean vessel area (p=0.020) and geodesic distance (p=0.048) decreased significantly. Multivariate analysis demonstrated baseline ischaemic index and Goldberg stage are correlated with progression.ConclusionLongitudinal ischaemic index and retinal vascular parameter measurements demonstrate statistically significant progression in SCR. The clinical significance of these relatively small magnitude changes remains unclear but may provide insights into the progression of retinal ischaemia in SCR.

scholarly journals Creation of complexity assessment tool for patients receiving home care

2016 ◽  
Vol 50 (3) ◽  
pp. 434-441 ◽  
Author(s):  
Maria Leopoldina de Castro Villas Bôas ◽  
Helena Eri Shimizu ◽  
Mauro Niskier Sanchez
Keyword(s):  
Confidence Interval ◽  
Home Care ◽  
Sensitivity And Specificity ◽  
Gold Standard ◽  
Assessment Tool ◽  
Kappa Statistic ◽  
Validity And Reliability ◽  
Care Plans ◽  
Accuracy Study ◽  
Complexity Assessment

Abstract OBJECTIVE To create and validate a complexity assessment tool for patients receiving home care from a public health service. METHOD A diagnostic accuracy study, with estimates for the tool's validity and reliability. Measurements of sensitivity and specificity were considered when producing validity estimates. The resulting tool was used for testing. Assessment by a specialized team of home care professionals was used as the gold standard. In the tool's reliability study, the authors used the Kappa statistic. The tool's sensitivity and specificity were analyzed using various cut-off points. RESULTS On the best cut-off point-21-with the gold standard, a sensitivity of 75.5% was obtained, with the limits of confidence interval (95%) at 68.3% and 82.8% and specificity of 53.2%, with the limits of confidence interval (95%) at 43.8% and 62.7%. CONCLUSION The tool presented evidence of validity and reliability, possibly helping in service organization at patient admission, care type change, or support during the creation of care plans.

scholarly journals Research on a Sliding Detection Method for an Elevator Traction Wheel Based on Machine Vision

Symmetry ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1158
Author(s):  
Jiayan Chen ◽  
Limeng Jing ◽  
Tao Hong ◽  
Hui Liu ◽  
Adam Glowacz
Keyword(s):  
Machine Vision ◽  
Detection Method ◽  
Region Of Interest ◽  
Absolute Error ◽  
Wire Rope ◽  
Geometric Transformation ◽  
Signal Processing Algorithm ◽  
Centroid Method ◽  
Object Distance ◽  
The Wire

To solve the problem that the elevator traction wheel slippage is difficult to detect quantitatively, a slippage detection method is proposed based on machine vision. The slip between the traction wheel and the wire rope will occur during the round-trip operation of the elevator, the displacement distance between the traction wheel and the wire rope in the circumferential direction is obtained through the image signal processing algorithm and related data analysis. First, the ROI (region of interest) of the collected original image is selected to reduce redundant information. Then, a nonlinear geometric transformation is carried out to transform the image into the target image with an equal object distance. Finally, the centroid method is used to obtain the slippage between the traction wheel and the wire rope. The field test results show that the absolute error of the system developed in this paper is 0.74 mm and the relative error is 2%, the extending uncertainty of the slip detection results is (33.8 ± 0.69) mm, the confidence probability is p = 0.95, and the degree of freedom is v = 8, which can meet accuracy requirements of elevator maintenance.

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