scholarly journals Repeatability, Reproducibility, and Comparability of Subjective and Objective Measurements of Intraocular Forward Scattering in Healthy Subjects

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Ayaka Iijima ◽  
Kimiya Shimizu ◽  
Hidenaga Kobashi ◽  
Aya Saito ◽  
Kazutaka Kamiya
Keyword(s):  
Healthy Subjects ◽  
Intraclass Correlation ◽  
Correlation Coefficients ◽  
Forward Scattering ◽  
Intraclass Correlation Coefficients ◽  
Spread Function ◽  
Good Repeatability ◽  
Repeatability And Reproducibility ◽  
The Mean ◽  
Scattering Index

Purpose. To assess the repeatability, reproducibility, and comparability of measurements of subjective and objective forward scattering in healthy subjects.Methods. We prospectively examined twenty eyes of 20 healthy volunteers (7 men and 13 women; ages, 28.4 ± 4.1 years). The logarithmic straylight value (log(s)) and the objective scattering index (OSI) were measured with a straylight meter (C-Quant) and a point-spread function meter (OQAS), respectively.Results. The 95% limits of agreement (LoA) between first and second measurements ranged from −0.211 to 0.207 for the C-Quant and from −0.302 to 0.477 for the OQAS. The intraclass correlation coefficients for the repeatability of the log(s) and OSI measurements were 0.815 and 0.926, respectively. The mean difference between examiners was −0.051 ± 0.133 (95% LoA; −0.311 to 0.209) for the C-Quant and 0.080 ± 0.307 (−0.522 to 0.682) for the OQAS. There was a modest, but significant, correlation between the log(s) and the OSI (Spearman correlation coefficientr=0.498,p=0.026).Conclusions. The C-Quant and the OQAS provide good repeatability and reproducibility, although the OQAS measurement provides a slightly higher ICC than the C-Quant measurement. The subjective forward scattering may be to some extent expressed in the objective forward scattering in healthy subjects.

scholarly journals A Quantitative Comparison of Multispectral Refraction Topography and Autorefractometer in Young Adults

2021 ◽  
Vol 8 ◽  
Author(s):  
Yunru Liao ◽  
Zhenlan Yang ◽  
Zijing Li ◽  
Rui Zeng ◽  
Jing Wang ◽  
...  
Keyword(s):  
Correlation Coefficient ◽  
Pearson Correlation ◽  
Intraclass Correlation ◽  
Correlation Coefficients ◽  
Cross Sectional Study ◽  
Cross Sectional ◽  
High Agreement ◽  
Intraclass Correlation Coefficients ◽  
Repeatability And Reproducibility ◽  
The Mean

Purpose: Purpose of this study is to evaluate the measuring consistency of central refraction between multispectral refraction topography (MRT) and autorefractometry.Methods: This was a descriptive cross-sectional study including subjects in Sun Yat-sen Memorial Hospital from September 1, 2020, to December 31, 2020, ages 20 to 35 years with a best corrected visual acuity of 20/20 or better. All patients underwent cycloplegia, and the refractive status was estimated with autorefractometer, experienced optometrist and MRT. We analyzed the central refraction of the autorefractometer and MRT. The repeatability and reproducibility of values measured using both devices were evaluated using intraclass correlation coefficients (ICCs).Results: A total of 145 subjects ages 20 to 35 (290 eyes) were enrolled. The mean central refraction of the autorefractometer was −4.69 ± 2.64 diopters (D) (range −9.50 to +4.75 D), while the mean central refraction of MRT was −4.49 ± 2.61 diopters (D) (range −8.79 to +5.02 D). Pearson correlation analysis revealed a high correlation between the two devices. The intraclass correlation coefficient (ICC) also showed high agreement. The intrarater and interrater ICC values of central refraction were more than 0.90 in both devices and conditions. At the same time, the mean central refraction of experienced optometrist was −4.74 ± 2.66 diopters (D) (range −9.50 to +4.75D). The intra-class correlation coefficient of central refraction measured by MRT and subjective refraction was 0.939.Conclusions: Results revealed that autorefractometry, experienced optometrist and MRT show high agreement in measuring central refraction. MRT could provide a potential objective method to assess peripheral refraction.

scholarly journals Precision of Corneal Thickness Measurements Obtained Using the Scheimpflug-Placido Imaging and Agreement with Ultrasound Pachymetry

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Jinhai Huang ◽  
Giacomo Savini ◽  
Chengfang Wang ◽  
Weicong Lu ◽  
Rongrong Gao ◽  
...  
Keyword(s):  
Healthy Subjects ◽  
Corneal Thickness ◽  
Intraclass Correlation ◽  
Normal Subjects ◽  
Limits Of Agreement ◽  
Ultrasound Pachymetry ◽  
Good Repeatability ◽  
Repeatability And Reproducibility ◽  
The Mean ◽  
Thickness Measurements

Purpose.To assess the reliability and comparability of measuring central corneal thickness (CCT) and thinnest corneal thickness (TCT) using a new Scheimpflug-Placido analyzer (TMS-5, Japan) and ultrasound (US) pachymetry.Methods.Seventy-six healthy subjects were prospectively measured 3 times by 1 operator using the TMS-5, 3 additional consecutive scans were performed by a second operator, and ultrasound (US) pachymetry measurements were taken. The test-retest repeatability (TRT), coefficient of variation (CoV), and intraclass correlation coefficient (ICC) were calculated to evaluate intraoperator repeatability and interoperator reproducibility. Agreement among the devices was assessed using Bland-Altman plots and 95% limits of agreement (LoA).Results.The intraoperators TRT and CoV were <19 μm and 2.0%, respectively. The interoperators TRT and CoV were <12 μm and 1.0%, respectively, and ICC was >0.90. The mean CCT and TCT measurements using the TMS-5 were 15.97 μm (95% LoA from −26.42 to −5.52 μm) and 20.32 μm (95% LoA from −30.67 to −9.97 μm) smaller, respectively, than those using US pachymetry.Conclusions.The TMS-5 shows good repeatability and reproducibility for measuring CCT and TCT in normal subjects but only moderate agreement with US pachymetry results. Caution is warranted before using these techniques interchangeably.

scholarly journals An Electromyographic Analysis of the Deep Cervical Flexor Muscles in Performance of Craniocervical Flexion

2003 ◽  
Vol 83 (10) ◽  
pp. 899-906 ◽  
Author(s):  
Deborah Falla ◽  
Gwendolen Jull ◽  
Paul Dall'Alba ◽  
Alberto Rainoldi ◽  
Roberto Merletti
Keyword(s):  
Muscle Activity ◽  
Intraclass Correlation ◽  
Correlation Coefficients ◽  
Bipolar Electrodes ◽  
Intraclass Correlation Coefficients ◽  
Reliability Estimates ◽  
Flexor Muscles ◽  
The Mean ◽  
Electromyographic Analysis ◽  
Electromyographic Signals

Abstract Background and Purpose. This study evaluated an electromyographic technique for the measurement of muscle activity of the deep cervical flexor (DCF) muscles. Electromyographic signals were detected from the DCF, sternocleidomastoid (SCM), and anterior scalene (AS) muscles during performance of the craniocervical flexion (CCF) test, which involves performing 5 stages of increasing craniocervical flexion range of motion—the anatomical action of the DCF muscles. Subjects. Ten volunteers without known pathology or impairment participated in this study. Methods. Root-mean-square (RMS) values were calculated for the DCF, SCM, and AS muscles during performance of the CCF test. Myoelectric signals were recorded from the DCF muscles using bipolar electrodes placed over the posterior oropharyngeal wall. Reliability estimates of normalized RMS values were obtained by evaluating intraclass correlation coefficients and the normalized standard error of the mean (SEM). Results. A linear relationship was evident between the amplitude of DCF muscle activity and the incremental stages of the CCF test (F=239.04, df=36, P&lt;.0001). Normalized SEMs in the range 6.7% to 10.3% were obtained for the normalized RMS values for the DCF muscles, providing evidence of reliability for these variables. Discussion and Conclusion. This approach for obtaining a direct measure of the DCF muscles, which differs from those previously used, may be useful for the examination of these muscles in future electromyographic applications.

Is the location of the signal intensity weighted centroid a reliable measurement of fluid displacement within the disc?

2018 ◽  
Vol 63 (4) ◽  
pp. 453-460 ◽  
Author(s):  
Vahid Abdollah ◽  
Eric C. Parent ◽  
Michele C. Battié
Keyword(s):  
Signal Intensity ◽  
Water Distribution ◽  
Intraclass Correlation ◽  
Correlation Coefficients ◽  
Region Of Interest ◽  
Rater Reliability ◽  
Fluid Displacement ◽  
Intraclass Correlation Coefficients ◽  
The Mean ◽  
Standard Error Of Measurement

Abstract Degenerated discs have shorter T2-relaxation time and lower MR signal. The location of the signal-intensity-weighted-centroid reflects the water distribution within a region-of-interest (ROI). This study compared the reliability of the location of the signal-intensity-weighted-centroid to mean signal intensity and area measurements. L4-L5 and L5-S1 discs were measured on 43 mid-sagittal T2-weighted 3T MRI images in adults with back pain. One rater analysed images twice and another once, blinded to measurements. Discs were semi-automatically segmented into a whole disc, nucleus, anterior and posterior annulus. The coordinates of the signal-intensity-weighted-centroid for all regions demonstrated excellent intraclass-correlation-coefficients for intra- (0.99–1.00) and inter-rater reliability (0.97–1.00). The standard error of measurement for the Y-coordinates of the signal-intensity-weighted-centroid for all ROIs were 0 at both levels and 0 to 2.7 mm for X-coordinates. The mean signal intensity and area for the whole disc and nucleus presented excellent intra-rater reliability with intraclass-correlation-coefficients from 0.93 to 1.00, and 0.92 to 1.00 for inter-rater reliability. The mean signal intensity and area had lower reliability for annulus ROIs, with intra-rater intraclass-correlation-coefficient from 0.5 to 0.76 and inter-rater from 0.33 to 0.58. The location of the signal-intensity-weighted-centroid is a reliable biomarker for investigating the effects of disc interventions.

scholarly journals Deaminase associated single nucleotide variants in blood and saliva-derived exomes from healthy subjects

2019 ◽  
Author(s):  
Nathan E. Hall ◽  
Jared Mamrot ◽  
Christopher M.A. Frampton ◽  
Prue Read ◽  
Edward J. Steele ◽  
...  
Keyword(s):  
Exome Sequencing ◽  
Whole Exome Sequencing ◽  
Healthy Subjects ◽  
Intraclass Correlation ◽  
Correlation Coefficients ◽  
Healthy Individuals ◽  
Intraclass Correlation Coefficients ◽  
Whole Exome ◽  
The Impact ◽  
Group 1

AbstractBackgroundDeaminases play an important role in shaping inherited and somatic variants. Disease related SNVs are associated with deaminase mutagenesis and genome instability. Here, we investigate the reproducibility and variance of whole exome SNV calls in blood and saliva of healthy subjects and analyze variants associated with AID, ADAR, APOBEC3G and APOBEC3B deaminase sequence motifs.MethodsSamples from twenty-four healthy Caucasian volunteers, allocated into two groups, underwent whole exome sequencing. Group 1 (n=12) analysis involved one blood and four saliva replicates. A single saliva sample was sequenced for Group 2 subjects (n=12). Overall, a total of 72 whole exome datasets were analyzed. Biological (Group 1 & 2) and technical (Group 1) variance of SNV calls and deaminase metrics were calculated and analyzed using intraclass correlation coefficients. Candidate somatic SNVs were identified and evaluated.ResultsWe report high blood-saliva concordance in germline SNVs from whole exome sequencing. Concordant SNVs, found in all subject replicates, accounted for 97% of SNVs located within the protein coding sequence of genes. Discordant SNVs have a 30% overlap with variants that fail gnomAD quality filters and are less likely to be found in dbSNP. SNV calls and deaminase-associated metrics were found to be reproducible and robust (intraclass correlation coefficients >0.95). No somatic SNVs were conclusively identified when comparing blood and saliva samples.ConclusionsSaliva and blood both provide high quality sources of DNA for whole exome sequencing, with no difference in ability to resolve SNVs and deaminase-associated metrics. We did not identify somatic SNVs when comparing blood and saliva of healthy individuals, and we conclude that more specialized investigative methods are required to comprehensively assess the impact of deaminase activity on genome stability in healthy individuals.

scholarly journals Ultrasonography Method of Deep Cervical Muscles and Thickness Measurement Reliability in Cervicogenic Headache and Healthy Subjects:APilot Study

2021 ◽  
Author(s):  
Omolbanin Abaspour ◽  
Mohammad Akbari ◽  
Asghar Rezasoltani
Keyword(s):  
Healthy Subjects ◽  
Intraclass Correlation ◽  
Correlation Coefficients ◽  
Muscle Thickness ◽  
Cervicogenic Headache ◽  
Thickness Measurement ◽  
Neck Muscle ◽  
Ultrasound Images ◽  
Intraclass Correlation Coefficients ◽  
Linear Probe

Introduction: In Cervicogenic Headache (CGH), motor control of muscles is impaired and deep upper neck muscles (extensor and flexor muscles) become atrophied. In this research, thickness measurement of Longus Capitis (LCap), Rectus Capitis Posterior Major (RCPM), and Obliquus Capitis Superior (OCS) muscles were conducted and intra-rater reliability of the thickness measurement of these muscles was assessed in CGH and healthy subjects. Materials and Methods: Twenty subjects, including 10 healthy subjects (19-32 years old) and 10 CGH patients (20-35 years old) participated in this study. LCap thickness was measured at the level of C3-C4 in the supine position and posterior muscles (RCPM and OCS) thickness at the C1-C2 level in the sitting position. All ultrasound images were captured by a linear probe with a 50-mm footprint in B mode option and frequency range of 9-12 Hz. Intraclass Correlation Coefficients (ICC), Standard Error Of Measurement (SEM), and the Smallest Detectable Difference (SDD) were calculated for data analysis. Results: The ICC for thickness measurement of LCap was from 0.70 to 0.91 (good to excellent), for RCPM thickness was from 0.69 to 0.94 and for OCS muscle thickness was from 0.87 to 0.98. SEM values for LCap were between 0.08 and 0.25 and the SDD values between 0.22 and 0.71. SEM values for RCPM were between 0.22 and 0.43 and these values were reported for OCS muscle between 0.19 and 0.45. Conclusion: The results indicated that the presented position and the level of ultrasonography in this study are appropriate and ultrasound is a reliable tool to measure the deep upper neck muscle thickness in CGH and healthy subjects.

scholarly journals Acceleration of 2D-MR fingerprinting by reducing the number of echoes with increased in-plane resolution: a volunteer study

2020 ◽  
Vol 33 (6) ◽  
pp. 783-791
Author(s):  
Yusuke Yokota ◽  
Tomohisa Okada ◽  
Yasutaka Fushimi ◽  
Akira Yamamoto ◽  
Satoshi Nakajima ◽  
...  
Keyword(s):  
Intraclass Correlation ◽  
Correlation Coefficients ◽  
Region Of Interest ◽  
Intraclass Correlation Coefficients ◽  
Coefficients Of Variation ◽  
Volunteer Study ◽  
The Mean ◽  
T1 And T2 ◽  
High Repeatability ◽  
Measurement Repeatability

Abstract Objective To compare the absolute values and repeatability of magnetic resonance fingerprinting (MRF) with 3000 and 1500 echoes/slice acquired in 41 s and 20 s (MRF3k and MRF1.5k, respectively). Materials and methods MRF3k and MRF1.5k scans based on fast imaging with steady precession (FISP) were conducted using a 3 T scanner. Inter-scan agreement and intra-scan repeatability were investigated in 41 and 28 subjects, respectively. Region-of-interest (ROI) analysis was conducted on T1 values of MRF3k by two raters, and their agreement was evaluated using intraclass correlation coefficients (ICCs). Between MRF3k and MRF1.5k, differences in T1 and T2 values and inter-measurement correlation coefficients (CCs) were investigated. Intra-measurement repeatability was evaluated using coefficients of variation (CVs). A p value < 0.05 was considered statistically significant. Results The ICCs of ROI measurements were 0.77–0.96. Differences were observed between the two MRF scans, but the CCs of the overall ROIs were 0.99 and 0.97 for the T1 and T2 values, respectively. The mean and median CVs of repeatability were equal to or less than 1.58% and 3.13% in each of the ROIs for T1 and T2, respectively; there were some significant differences between MRF3k and MRF1.5k, but they were small, measuring less than 1%. Discussion Both MRF3k and MRF1.5k had high repeatability, and a strong to very strong correlation was observed, with a trend toward slightly higher values in MRF1.5k.

The choice of chromogen and reliability of contact rhinoscopy in the irradiated nasopharynx

2007 ◽  
Vol 122 (2) ◽  
pp. 177-180 ◽  
Author(s):  
Martin W Pak ◽  
Samuel Chow ◽  
C A van Hasselt
Keyword(s):  
Methylene Blue ◽  
Squamous Metaplasia ◽  
Intraclass Correlation ◽  
Correlation Coefficients ◽  
Cross Sectional ◽  
Vital Stain ◽  
Intraclass Correlation Coefficients ◽  
Observer Reliability ◽  
Blue Stain ◽  
The Mean

AbstractA cross-sectional randomised single blind study was conducted to assess how concentrations of chromogen (vital stain) and the characteristics of the assessors affect the assessment of contact rhinoscopy. Twenty-eight patients who had undergone external radiotherapy for nasopharyngeal carcinoma were assessed by contact rhinoscopy using 0.5 per cent and 1 per cent methylene blue stain on opposite sides of the nasopharynx. Three independent observers assessed the visual clarity of the 45 contact endoscopic images showing squamous metaplasia according to a visual analogue scale. The intraclass correlation coefficients were 0.916 to 0.957 and 0.839 to 0.964 for intra-observer reliability of assessors in the groups of 0.5 per cent and 1 per cent stains, respectively. The intraclass correlation coefficients for inter-observer reliability of assessors were 0.884 and 0.885 in the groups of 0.5 per cent and 1 per cent stains, respectively. The mean scores of clarity of the cellular details were statistically higher in the group of 1 per cent stain among all assessors. These results showed that the assessment of squamous metaplasia by contact endoscopy is highly reliable irrespective of the clinical experience and knowledge of histopathology of the assessors. One per cent methylene blue should be the vital stain of choice in contact endoscopy.

Cadence, Age, and Weight as Determinants of Forefoot Plantar Pressures Using the Biofoot In-shoe System

2008 ◽  
Vol 98 (4) ◽  
pp. 302-310 ◽  
Author(s):  
Alfonso Martínez-Nova ◽  
Javier Pascual Huerta ◽  
Raquel Sánchez-Rodríguez
Keyword(s):  
Healthy Subjects ◽  
Intraclass Correlation ◽  
Correlation Coefficients ◽  
Metatarsal Head ◽  
Multiple Regression Model ◽  
Good Reliability ◽  
Intraclass Correlation Coefficients ◽  
Plantar Pressures ◽  
Foot Biomechanics ◽  
Peak Plantar Pressure

Background: We evaluated normal plantar pressures and studied the effect of weight, cadence, and age on forefoot plantar pressures in healthy subjects by using the Biofoot (Instituto de Biomecánica de Valencia, Valencia, Spain) in-shoe measurement system. Methods: The feet of 45 healthy subjects with no evident foot or lower-limb diseases were measured with the Biofoot in-shoe system. The forefoot was divided into seven areas: the first through fifth metatarsal heads, the hallux, and the second through fifth lesser toes. Three trials of 8 sec each were recorded twice in each subject, and the mean was used to analyze peak and mean plantar pressures. A multiple regression model including weight, age, and cadence was run for each metatarsal head, the hallux, and the lesser toes. Intraclass correlation coefficients and coefficients of variation were also calculated to assess reliability. Results: The second metatarsal head had the greatest peak (960 kPa) and mean (585.1 kPa) pressures, followed by the third metatarsal head. Weight and cadence combined explained 18% and 23% of peak plantar pressure at the second and third metatarsal heads, respectively (P &lt; .001). The intraclass correlation coefficient varied from 0.76 to 0.96 for all variables. The coefficient of variation between sessions ranged from 5.8% to 9.0%. Conclusion: The highest peak and mean plantar pressures were found at the second and third metatarsal heads in healthy subjects. Weight, cadence, and age explained a low variability of this pressure pattern. The Biofoot in-shoe system has good reliability to measure plantar pressures. These data will have implications for the understanding of normal foot biomechanics and its determinants. (J Am Podiatr Med Assoc 98(4): 302–310, 2008)

scholarly journals Evaluating the Consistency, Repeatability, and Reproducibility of Osteometric Data on Dry Bone Surfaces, Scanned Dry Bone Surfaces, and Scanned Bone Surfaces Obtained from Living Individuals

2016 ◽  
Vol 29 (1-2) ◽  
pp. 33-53 ◽  
Author(s):  
L. Corron ◽  
F. Marchal ◽  
S. Condemi ◽  
K. Chaumoître ◽  
P. Adalian
Keyword(s):  
Computed Tomography ◽  
Statistical Tests ◽  
Intraclass Correlation ◽  
Lumbar Vertebrae ◽  
Correlation Coefficients ◽  
Intraclass Correlation Coefficients ◽  
Reconstructed Surfaces ◽  
Computed Tomography Scans ◽  
Repeatability And Reproducibility ◽  
Dry Bone

Applying dry bone osteometrics to virtual bone surfaces obtained via medical imaging raises the question of consistency between the variables. Variables obtained from virtual bone surfaces also need to be sufficiently repeatable and reproducible to be valid for anthropological studies. This is also true for the landmarks defining these variables and for their acquisition. The consistency between variables taken directly from dry bones and from the virtual surfaces of dry bones was tested on 40 clavicles. 30 virtual surfaces of iliae, fifth lumbar vertebrae, and clavicles reconstructed from computed tomography scans of living individuals were used to test the repeatability and reproducibility of 16 landmarks and 19 variables. Statistical tests, graphical and quantitative error evaluations, and intraclass correlation coefficients were applied. The differences between all variables taken on dry and virtual clavicles were less than ±1 mm. Bland–Altman plots showed more than 95% reliability between variables obtained on dry bone and their virtually reconstructed surfaces, confirming their consistency and thus validating their use in osteometric studies independently of the medium of study. Although not all landmarks were repeatable and reproducible, most variables were. To assess intra- or inter-observer errors, graphical representations or coefficients are more precise and accurate than statistical tests. These two evaluation methods should be given priority to test the repeatability and reproducibility of osteometric variables.

Sign in / Sign up

Export Citation Format

Share Document