scholarly journals A robust permutation test for the concordance correlation coefficient

2021 ◽  
Author(s):  
Alan D. Hutson ◽  
Han Yu
Keyword(s):  
Correlation Coefficient ◽  
Permutation Test ◽  
Concordance Correlation Coefficient ◽  
Concordance Correlation

A repeated measures concordance correlation coefficient

2007 ◽  
Vol 26 (16) ◽  
pp. 3095-3113 ◽  
Author(s):  
Tonya S. King ◽  
Vernon M. Chinchilli ◽  
Josep L. Carrasco
Keyword(s):  
Correlation Coefficient ◽  
Repeated Measures ◽  
Concordance Correlation Coefficient ◽  
Concordance Correlation

scholarly journals MRI texture feature repeatability and image acquisition factor robustness, a phantom study and in silico study

2021 ◽  
Vol 5 (1) ◽  
Author(s):  
Joshua Shur ◽  
Matthew Blackledge ◽  
James D’Arcy ◽  
David J. Collins ◽  
Maria Bali ◽  
...  
Keyword(s):  
Correlation Coefficient ◽  
Coefficient Of Variation ◽  
In Silico ◽  
Image Acquisition ◽  
Texture Feature ◽  
Texture Features ◽  
Concordance Correlation Coefficient ◽  
Concordance Correlation ◽  
Simulation Data ◽  
Mri Features

Abstract Purpose To evaluate robustness and repeatability of magnetic resonance imaging (MRI) texture features in water and tissue phantom test-retest study. Materials and methods Separate water and tissue phantoms were imaged twice with the same protocol in a test-retest experiment using a 1.5-T scanner. Protocols were acquired to favour signal-to-noise ratio and resolution. Forty-six features including first order statistics and second-order texture features were extracted, and repeatability was assessed by calculating the concordance correlation coefficient. Separately, base image noise and resolution were manipulated in an in silico experiment, and robustness of features was calculated by assessing percentage coefficient of variation and linear correlation of features with noise and resolution. These simulation data were compared with the acquired data. Features were classified by their degree (high, intermediate, or low) of robustness and repeatability. Results Eighty percent of the MRI features were repeatable (concordance correlation coefficient > 0.9) in the phantom test-retest experiment. The majority (approximately 90%) demonstrated a strong or intermediate correlation with image acquisition parameter, and 19/46 (41%) and 13/46 (28%) of features were highly robust to noise and resolution, respectively (coefficient of variation < 5%). Agreement between the acquired and simulation data varied, with the range of agreement within feature classes between 11 and 92%. Conclusion Most MRI features were repeatable in a phantom test-retest study. This phantom data may serve as a lower limit of feature MRI repeatability. Robustness of features varies with acquisition parameter, and appropriate features can be selected for clinical validation studies.

scholarly journals AB0798 IS THERE A REPRODUCIBILITY OF THE HISTOGRAM AND GRAY SCALE IN ECOEXTRUCTURAL DAMAGES IN RHEUMATOTOLOGICAL DISEASES?

2021 ◽  
Vol 80 (Suppl 1) ◽  
pp. 1423.2-1424
Author(s):  
J. A. Mendonça ◽  
I. Siste de Almeida Aoki ◽  
C. C. Cavuto ◽  
V. A. Leandro-Merhi ◽  
J. L. B. D. Aquino
Keyword(s):  
Correlation Coefficient ◽  
Intraclass Correlation Coefficient ◽  
Rheumatic Diseases ◽  
Femoral Condyle ◽  
Intraclass Correlation ◽  
Correlation Coefficients ◽  
Concordance Correlation Coefficient ◽  
Image Method ◽  
Concordance Correlation ◽  
Gray Scale

Background:The gray scale (GS) in high resolution ultrasound is already well validated for use in rheumatological diseases, but the color map or the histogram, can be considered a new proposal, to better define and complement the echotextural damages detection1.Objectives:To calculate the lesions area measures reproducibility index in arthropathies, between 3 blind evaluators and correlate these measures using the GS and the histogram.Methods:Observational and retrospective study approved by the ethics committee of the Pontifical Catholic University of Campinas, with the opinion number: 1.526.307. A total of 29 patients have been assessed (31% males and 69% females) on period 2014 to 2019 in Rheumatology service. A MyLab 50 -Esaote equipment was used with frequency transducer that ranged between 6.0 and 18.0 MHz, 10 different area measures were performed from each recorded images previously, by the GS and the histogram. Statistical analysis: Spearman’s correlation coefficients, Lin’s concordance coefficient (CCC) and the intraclass correlation coefficient (ICC) and their respective 95% confidence intervals, with the SPSS software package for Windows v. 17.0 (SPSS Inc., Chicago, IL, USA).Results:Average age 43.5 ± 21.5 years of age; with disease duration that varied between ≤ 1 month (48.3%) and ≥36 months (24.1%); with the following diseases: juvenile idiopathic arthritis (17.24%); osteoarthritis (13.79%); psoriatic arthritis (13.79%); undifferentiated spondyloarthritis (3.44%); gout (20.68%); rheumatoid arthritis (27.58%) and reactive arthritis (3.44%). A total of 840 measures of exudative (27.58%), proliferative (27.58%) and snowstorm appearance (6.89%) synovitis were performed; femoral-condyle cartilage (3.44%); synovial cyst (3.44%); paratendinitis (6.89%); calcification (3.44%); nail enthesitis (3.44%); tenosynovitis (6.89%) and tophi (10.34%) (Figure 1). The concordance correlation coefficient showed values closer to 1; p <0.001, the intraclass correlation coefficients with excellent reproducibility (ICC ≥ 0.75); p <0.001, always in relation to the three evaluators (Table 1) and the Spearman correlation between the GS and the histogram ranged from rs = 0.665 to rs = 1,000; p <0.001.Conclusion:The histogram can be considered an image method to better identify echotextural damages.References:[1]Mendonça J, Provenza J, Guissa V, et al AB1059 2D Histogram Ultrasound and 3D Ultrasound Correlation in Rheumatic Diseases Annals of the Rheumatic Diseases 2015; 74:1253-1254.Table 1.Concordance Correlation Coefficient (CCC) and Intraclass Correlation Coefficient (ICC):EvaluatorsGS - CCC(IC 95%)p-valorHistogram (IC 95%)p-valor1 e 20,998(0,994-0,999)<0,0010,999(0,995-1,000)<0,0011 e 30,998(0,995-0,999)<0,0010,999(0,995-1,000)<0,0012 e 30,992(0,980-0,997)<0,010,996(0,979-0,999)<0,01Standard by US 2DICCp-valorGS0,997(0,992-0,999)<0,001Histogram0,998(0,992-0,999)<0,001Legends: Gray Scale (GS).Figure 1.Patient with gout: A and B: Tophi area measures (star) in right metatarsos and efusion (arrow) by GS (45 mm2) and histogram (39 mm2), respectively.Disclosure of Interests:José Alexandre Mendonça Speakers bureau: Novartis, Janssen, Bristol, UCB, Isabella Siste de Almeida Aoki: None declared, Caique Chagas Cavuto: None declared, Vânia Aparecida Leandro-Merhi: None declared, José Luis Braga de Aquino: None declared

A Bayesian Framework for Estimating the Concordance Correlation Coefficient Using Skew-elliptical Distributions

2018 ◽  
Vol 14 (1) ◽  
Author(s):  
Dai Feng ◽  
Richard Baumgartner ◽  
Vladimir Svetnik
Keyword(s):  
Clinical Study ◽  
Missing Data ◽  
Correlation Coefficient ◽  
Real Life ◽  
Bayesian Framework ◽  
Concordance Correlation Coefficient ◽  
Elliptical Distributions ◽  
Concordance Correlation ◽  
Heavy Tailed ◽  
Biomarker Data

Abstract The concordance correlation coefficient (CCC) is a widely used scaled index in the study of agreement. In this article, we propose estimating the CCC by a unified Bayesian framework that can (1) accommodate symmetric or asymmetric and light- or heavy-tailed data; (2) select model from several candidates; and (3) address other issues frequently encountered in practice such as confounding covariates and missing data. The performance of the proposal was studied and demonstrated using simulated as well as real-life biomarker data from a clinical study of an insomnia drug. The implementation of the proposal is accessible through a package in the Comprehensive R Archive Network.

scholarly journals Standard area diagram set for scab quantification in trilobed leaves of the sour passion fruit

2020 ◽  
Vol 50 (3) ◽  
Author(s):  
Anne Pinheiro Costa ◽  
José Ricardo Peixoto ◽  
Luiz Eduardo Bassay Blum ◽  
Alexandre Bosco de Oliveira
Keyword(s):  
Correlation Coefficient ◽  
Bias Correction ◽  
Systematic Errors ◽  
Passion Fruit ◽  
Coefficient Of Determination ◽  
Concordance Correlation Coefficient ◽  
Concordance Correlation ◽  
Improve Accuracy ◽  
Severity Levels ◽  
Sour Passion Fruit

ABSTRACT: The study aimed to develop and validate a standard area diagram set (SADs) to improve accuracy, precision, and reproducibility in the assessment of scab severity in trilobed leaves of the sour passion fruit. The SADs comprised six severity levels (1%; 3%; 6%; 11%; 21%; and 33%). The SADs increased the accuracy of the estimates by reducing the constant and systematic errors, and the tendency to overestimate the actual severity, limited the number of evaluators who presented this trend, in addition to increasing the bias correction factor. The inexperienced evaluators were the ones that benefited the most from the SADs use. Once the SADs was introduced, 80% and 100% evaluators gave estimates free from constant and systematic errors, respectively. The improvement in precision was verified by the increase in the coefficient of determination and Lin’s concordance correlation coefficient, by reducing absolute errors and increasing the reproducibility of the estimates.

scholarly journals Combining F-Scan and GAITRite® for use in Clinical Gait Analysis: A Validation Study.

2020 ◽  
Author(s):  
Stephanie Speight ◽  
Selina Reidy ◽  
John Stephenson ◽  
Sarah Reel
Keyword(s):  
Gait Analysis ◽  
Correlation Coefficient ◽  
Intraclass Correlation Coefficient ◽  
Intraclass Correlation ◽  
Cost Effective ◽  
Quality Data ◽  
Concordance Correlation Coefficient ◽  
Concordance Correlation ◽  
Mean Values ◽  
Level Of Agreement

Abstract BackgroundClinical gait analysis is widely used to aid the assessment and diagnosis of symptomatic pathologies. Equipment based analysis provides clinicians with a more comprehensive assessment using pressure systems such as F-scan, or analysis of the spatial-temporal parameters of gait using GAITRite. There are systems however such as Strideway™ that can measure these parameters simultaneously, but can be expensive. This study aimed to determine whether standalone systems can be used collectively while still providing quality data, as a cost-effective alternative.MethodsTwenty-six participants walked on a standard floor and a GAITRite walkway, three times wearing the F-Scan system. Mid gait protocols were utilised by analysing the contact pressure of the 2 nd metatarsophalangeal joint of the third, fifth and seventh step from each walk. The Bland-Altman method was used to determine a level of agreement between the two surfaces, using mean values from all walks of all participants who successfully completed all required walks. The intraclass correlation coefficient and Lin’s concordance correlation coefficient were calculated as indices of reliability.ResultsThe intraclass correlation coefficient was calculated to be 0.991 and Lin’s concordance correlation coefficient for the data was calculated to be 0.956, indicating very good reproducibility.ConclusionsThe level of agreement in plantar pressures observed on the two surfaces was very high, suggesting that it is feasible to use F-Scan and GAITRite® together in a clinical setting, as an alternative to other less cost-effective standalone systems.

A short note on jackknifing the concordance correlation coefficient

2013 ◽  
Vol 33 (3) ◽  
pp. 514-516 ◽  
Author(s):  
Dai Feng ◽  
Richard Baumgartner ◽  
Vladimir Svetnik
Keyword(s):  
Correlation Coefficient ◽  
Short Note ◽  
Concordance Correlation Coefficient ◽  
Concordance Correlation

Comparison of Concordance Correlation Coefficient Estimating Approaches with Skewed Data

2007 ◽  
Vol 17 (4) ◽  
pp. 673-684 ◽  
Author(s):  
Josep L. Carrasco ◽  
Lluis Jover ◽  
Tonya S. King ◽  
Vernon M. Chinchilli
Keyword(s):  
Correlation Coefficient ◽  
Concordance Correlation Coefficient ◽  
Skewed Data ◽  
Concordance Correlation

Use of an algorithm applied to urine drug screening to assess adherence to an OxyContin® regimen

2018 ◽  
Vol 5 (6) ◽  
pp. 359-364 ◽  
Author(s):  
Joseph E. Couto, PharmD, MBA ◽  
Lynn Webster, MD, FACPM, FASAM ◽  
Martha C. Romney, MS, JD, MPH ◽  
Harry L. Leider, MD, MBA ◽  
Ariel Linden, DrPH, MS
Keyword(s):  
Correlation Coefficient ◽  
Confidence Intervals ◽  
Study Participant ◽  
Concordance Correlation Coefficient ◽  
Concordance Correlation ◽  
Drug Levels ◽  
Urine Drug ◽  
High Doses ◽  
To Receive ◽  
Adult Volunteers

Objective: This study examined the ability of an algorithm applied to urine drug levels of oxycodone in healthy adult volunteers to differentiate among low, medium, and high doses of OxyContin®.Participants and interventions: Thirty-six healthy volunteers were randomized to receive 80, 160, or 240 mg of daily OxyContin® to steady state while under a naltrexone blockade. During days 3 and 4 of the study, urine samples of all participants were collected, and oxycodone levels detected in the urine were obtained using a liquid chromatography-mass spectrometry (LC-MS-MS) assay.Outcome measures: The concordance was calculated for raw and adjusted LC-MS-MS urine oxycodone values within each study participant between their third and fourth day values. Also, an analysis of medians was calculated for each of the dosage groupings using Bonett-Price confidence intervals for both raw and adjusted LC-MS-MS values.Results: The concordance correlation coefficient for the raw LC-MS-MS values between days 3 and 4 was 0.689 (95% confidence intervals = 0.515, 0.864), whereas the concordance correlation coefficient for the LC-MS-MS values using the algorithm (ie, normalized values) was 0.882 (95% confidence intervals = 0.808, 0.956). Because of greater variability in the raw values, some overlap was observed in the confidence intervals of the various OxyContin® doses, whereas no overlap was observed in the normalized confidence intervals regardless of the application of a Bonferroni adjustment.Conclusions: In contrast to raw LC-MS-MS values, an algorithm that normalizes oxycodone urine drug levels for pH, specific gravity, and lean body mass discriminates well among all three of the daily doses of OxyContin® tested (80, 160, and 240 mg), even with correcting for multiple analyses.

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