Bland-Altman Research Articles

Exploring discrepancies in muscle analysis with ImageJ: understanding the impact of tool selection on echo intensity and muscle area measurements.

The aim was to compare the use of different tools within the ImageJ program (polygon vs. segmented line) and their impact on the calculation of muscle area and echo intensity (EI) values in ultrasound imaging of the vastus lateralis muscle. Thirteen volunteers participated in this study. Ultrasound images of the vastus lateralis muscle were acquired using 2D B-mode ultrasonography and analyzed using both the polygon and segmented line tools by the same evaluator. The intraclass correlation coefficient (ICC) and coefficient of variation (CV) assessed the tools' reliability. Bland-Altman plots were employed to verify the agreement between measurements, and linear regression analysis determined proportional bias. A paired t-test was conducted to analyze differences between the tools. The reliability between tools for muscle area calculation was weak (r = 0.000; CV = 138.03 ± 0.34%), while it was excellent for EI (r = 0.871; CV = 15.19 ± 2.96%). The Bland-Altman plots indicated a large bias for muscle area (d = 195.2%) with a proportional bias (p < 0.001). For EI, the bias was (d = 15.2) with proportional bias (p = 0.028). The paired t-test revealed significant differences between the tools for area (p < 0.001) but not for EI (p = 0.060). The study found significant differences in measurements obtained with the polygon and segmented line tools in ImageJ, with the polygon tool showing higher values for muscle area and lower values for EI.

Cross-cultural adaptation and measurement properties of the Brazilian Portuguese Version of the Parkinson’s Disease Sleep Scale (PDSS-2)

ObjectivesThe Parkinson’s Disease Sleep Scale-2 (PDSS-2) is an updated tool designed to identify specific sleep disturbances in individuals with Parkinson’s disease (PD). However, for its application in Brazil, a process of cross-cultural adaptation and validation of measurement properties was required. MethodsThis methodological study adapted the PDSS-2 to Brazilian Portuguese (PDSS-2-Br) and assessed its measurement properties (Internal consistency, test-retest reliability, measurement error, construct validity, and interpretability). The adapted scale was then tested on 2 occasions within an interval of 7 days, to 50 individuals with PD. Test–retest reliability was evaluated using kappa statistics (k) for the individual items, intraclass correlation coefficient (ICC) for the total scores, standard error of measurement (SEM), minimal detectable change (MDC) and Bland-Altman plot. Construct validity was assessed through Spearman correlation coefficients between the PDSS-2-Br and independent variables, while interpretability was evaluated by examining ceiling and floor effects. ResultsPDSS-2-Br showed satisfactory semantic, idiomatic, cultural, and conceptual equivalence. It also demonstrated good internal consistency (α=0.64), adequate test-retest reliability between items (κw 0.42-0.94, 95% CI=0.30-0.95) and total score (ICC=0.94; 95% CI=0.89-0.96), acceptable measurement error (SEM, 2.07 points; MDC, 5.74 points), absence of ceiling and floor effects, and 87,5% of pre-defined hypotheses were confirmed, indicating adequate construct validity (Spearman correlations coefficients for the rs=0.50, p<0.001) of the PDSS-2-Br. ConclusionThe measurement properties of the PDSS-2-Br are equivalent to those of the original version, and the scale has been validated and confirmed as reliable to measure sleep disorders among the Brazilian population with PD.

Agreement between lacrimal fluid and serum for detecting urea nitrogen and creatinine in dogs.

To determine whether urea nitrogen and creatinine levels differ in lacrimal fluid (LF) and serum (SER) in nonazotemic (control) and azotemic dogs and whether there is an agreement between LF and SER. A prospective observational study was performed at the Auburn University Small Animal Teaching Hospital between May 2023 and March 2024. Forty control and 38 azotemic dogs were enrolled. Twenty microliters of LF per eye was collected with microcapillary tubes, and 3 mL of blood was drawn. Bland-Altman plot and intraclass correlation coefficient (ICC) were used to evaluate the agreement between LF and SER. There was good agreement between LF and SER levels of urea nitrogen in the control group (Bland-Altman plot mean bias of -0.8108 ± 2.407 mg/dL; ICC of 0.874 [95% CI, 0.773 to 0.934]) and the azotemic group (Bland-Altman plot mean bias of -9.681 ± 23.89 mg/dL; ICC of 0.82 [95% CI, 0.658 to 0.906]). There was poor agreement between LF and SER concentrations for creatinine in the control and azotemic groups, with only 26 dogs with creatinine detectable in LF. Lacrimal fluid and SER concentrations of urea nitrogen showed good agreement in both the control and azotemic groups, whereas poor agreement was found for creatinine in both groups. Measurement of urea nitrogen in LF may provide an alternative to blood for diagnosing uremia. However, additional research is necessary before substituting LF for SER.

Resting energy expenditure in patients with liver cirrhosis: Indirect calorimetry vs. predictive equations.

The objective of our study was to explore the accuracy of previously published prediction equations in predicting resting energy expenditure (REE) in patients with liver cirrhosis (LC). We also aimed to develop a novel equation to estimate REE for Chinese patients with LC. In 90 patients with LC, the agreement between REE measured by Indirect calorimetry (IC) and predictive equations was quantified using paired T-test and visualized using a Bland-Altman Plot. Pearson correlation coefficient (R) was used to measure a linear correlation between REE measured by IC and different predictive equations. Stepwise multiple regression analysis was used to create a new REE equation. The estimated REEs of previous equations were underestimated against REE measured by IC (1610 ± 334 kcal). Lean body mass (LBM) was positively correlated with REE measured by IC (r = 0.723, p < 0.01). The newly derived estimation equation for REE (kcal) was 1274.3 - 209.0 * sex - 5.73 * age + 3.69 * waist circumference + 22.89 * LBM. The newly derived estimation equation was found to have a Pearson-r value of 0.765 compared with REE measured by IC. REE in liver cirrhosis was underestimated by using predictive equations. The new predictive equation developed by using age, sex, waist circumference, and LBM may help estimate REE in Chinese patients with LC accurately and easily.

Secondary fastener (tape) placement on a blood pressure cuff causes interindividual Doppler blood pressure measurement variability in healthy large-breed dogs.

The objective of this study was to compare Doppler blood pressure (DBP) measurements between blood pressure cuffs (BPCs) with and without a secondary fastener (tape) in healthy nonanesthetized large-breed dogs. 28 healthy dogs. Superficial palmar venous arch DBP measurements with and without tape on the BPC were performed in lateral recumbency with Doppler ultrasound. Each method was performed 6 consecutive times, with the final 5 values averaged. Bland-Altman plots were made and limits of agreement calculated. The limits of agreement were -40.8 (95% CI, -55.6 to -26.0) to 45.6 (95% CI, 30.8 to 60.4), indicating that the DBP measured with tape would be expected to be between 40.8 mm Hg below and 45.6 mm Hg above that measured without tape 95% of the time. The mean bias estimate was 2.4 mm Hg (SD, 22.0; 95% CI, -6.1 to 11.0; P = .724), indicating that DBP measurements with tape averaged 2.4 mm Hg higher than without tape. Doppler blood pressure measurements obtained with secondary fasteners on the BPCs differed by > 10 mm Hg compared to the BPCs' standard hook-and-loop fasteners 54% (30 of 56) of the time. Blood pressure cuffs with dysfunctional hook-and-loop fasteners should be replaced due to poor clinical reliability of DBP measurements. However, it is unclear whether Doppler sphygmomanometry is more accurate with the use of traditional Velcro BPC fasteners or with tape BPC fasteners.

Reproducibility of intravoxel incoherent motion quantification in the liver across field strengths and gradient hardware.

To evaluate reproducibility and interlobar agreement of intravoxel incoherent motion (IVIM) quantification in the liver across field strengths and MR scanners with different gradient hardware. Cramer-Rao lower bound optimization was performed to determine optimized monopolar and motion-robust 2D (b-value and first-order motion moment [M1]) IVIM-DWI acquisitions. Eleven healthy volunteers underwent diffusion MRI of the liver, where each optimized acquisition was obtained five times across three MRI scanners. For each data set, IVIM estimates (diffusion coefficient (D), pseudo-diffusion coefficients ( and ), blood velocity SDs (Vb1 and Vb2), and perfusion fractions [f1 and f2]) were obtained in the right and left liver lobes using two signal models (pseudo-diffusion and M1-dependent physical) with and without T2 correction (fc1 and fc2) and three fitting techniques (tri-exponential region of interest-based full and segmented fitting and blood velocity SD distribution fitting). Reproducibility and interlobar agreement were compared across methods using within-subject and pairwise coefficients of variation (CVw and CVp), paired sample t-tests, and Bland-Altman analysis. Using a combination of motion-robust 2D (b-M1) data acquisition, M1-dependent physical signal modeling with T2 correction, and blood velocity SD distribution fitting, multiscanner reproducibility with median CVw = 5.09%, 11.3%, 9.20%, 14.2%, and 12.6% for D, Vb1, Vb2, fc1, and fc2, respectively, and interlobar agreement with CVp = 8.14%, 11.9%, 8.50%, 49.9%, and 42.0%, respectively, was achieved. Recently proposed advanced IVIM acquisition, signal modeling, and fitting techniques may facilitate reproducible IVIM quantification in the liver, as needed for establishment of IVIM-based quantitative biomarkers for detection, staging, and treatment monitoring of diseases.

Interobserver reliability and accuracy of the visual assessment of interventricular septal flattening in pulmonary hypertension.

Interventricular septal (IVS) flattening is a key echocardiographic feature of pulmonary hypertension (PH) that is associated with worse outcomes. The accuracy and interobserver reliability of visual and quantitative measures of IVS in PH patients are poorly described. This single-center, retrospective analysis included 173 PH patients. All echocardiograms were independently interpreted by two board-certified echocardiographers, and IVS flattening was judged to be present visually and by calculating the eccentricity index (EI). A receiver operating characteristics analysis was conducted to determine the EI with the highest combination of sensitivity and specificity for visual IVS flattening. The agreement between the two echocardiographers for calculation of EI was assessed using Bland-Altman analysis. The overall percent agreement for visual IVS flattening was 72% with a Kappa coefficient of 0.27. Agreement was highest for patients with pre-capillary PH and lowest for those with isolated post-capillary PH. An EI cut-off of 1.5 had the highest combination of specificity (80%) and sensitivity (32%) to distinguish visual septal flattening. Bland-Altman analysis showed wide 95% limits of agreement between echocardiographers for EI measured during systole and diastole. There was a fair degree of agreement between two echo readers for the presence or absence of IVS flattening, which differed based on the hemodynamic subgroup of PH. Compared to the quantitative measure EI, visual assessment had a moderately high specificity but very low sensitivity for the presence of IVS flattening. Automated measures of IVS flattening should be considered to improve the accuracy and reliability of this key metric.

Ferumoxytol-Enhanced Cardiac Cine MRI Reconstruction Using a Variable-Splitting Spatiotemporal Network.

Balanced steady-state free precession (bSSFP) imaging is commonly used in cardiac cine MRI but prone to image artifacts. Ferumoxytol-enhanced (FE) gradient echo (GRE) has been proposed as an alternative. Utilizing the abundance of bSSFP images to develop a computationally efficient network that is applicable to FE GRE cine would benefit future network development. To develop a variable-splitting spatiotemporal network (VSNet) for image reconstruction, trained on bSSFP cine images and applicable to FE GRE cine images. Retrospective and prospective. 41 patients (26 female, 53 ± 19 y/o) for network training, 31 patients (19 female, 49 ± 17 y/o) and 5 healthy subjects (5 female, 30 ± 7 y/o) for testing. 1.5T and 3T, bSSFP and GRE. VSNet was compared to VSNet with total variation loss, compressed sensing and low rank methods for 14× accelerated data. The GRAPPA×2/×3 images served as the reference. Peak signal-to-noise-ratio (PSNR), structural similarity index (SSIM), left ventricular (LV) and right ventricular (RV) end-diastolic volume (EDV), end-systolic volume (ESV), and ejection fraction (EF) were measured. Qualitative image ranking and scoring were independently performed by three readers. Latent scores were calculated based on scores of each method relative to the reference. Linear mixed-effects regression, Tukey method, Fleiss' Kappa, Bland-Altman analysis, and Bayesian categorical cumulative probit model. A P-value <0.05 was considered statistically significant. VSNet achieved significantly higher PSNR (32.7 ± 0.2), SSIM (0.880 ± 0.004), rank (2.14 ± 0.06), and latent scores (-1.72 ± 0.22) compared to other methods (rank >2.90, latent score < -2.63). Fleiss' Kappa was 0.52 for scoring and 0.61 for ranking. VSNet showed no significantly different LV and RV ESV (P = 0.938) and EF (P = 0.143) measurements, but statistically significant different (2.62 mL) EDV measurements compared to the reference. VSNet produced the highest image quality and the most accurate functional measurements for FE GRE cine images among the tested 14× accelerated reconstruction methods. 3 TECHNICAL EFFICACY: Stage 1.

Impact of patient habitus and acquisition protocol on iodine quantification in dual-source photon-counting computed tomography.

Evaluation of iodine quantification accuracy with varying iterative reconstruction level, patient habitus, and acquisition mode on a first-generation dual-source photon-counting computed tomography (PCCT) system. A multi-energy CT phantom with and without its extension ring equipped with various iodine inserts (0.2 to 15.0mg/ml) was scanned over a range of radiation dose levels ( 0.5 to 15.0mGy) using two tube voltages (120, 140kVp) and two different source modes (single-, dual-source). To assess the agreement between nominal and measured iodine concentrations, iodine density maps at different iterative reconstruction levels were utilized to calculate root mean square error (RMSE) and generate Bland-Altman plots by grouping radiation dose levels (ultra-low: ; low: 1.5 to 5; medium: 5 to 15mGy) and iodine concentrations (low: ; high: 5 to 15mg/mL). Overall, quantification of iodine concentrations was accurate and reliable even at ultra-low radiation dose levels. RMSE ranged from 0.25 to 0.37, 0.20 to 0.38, and 0.25 to 0.37mg/ml for ultra-low, low, and medium radiation dose levels, respectively. Similarly, RMSE was stable at 0.31, 0.28, 0.33, and 0.30mg/ml for tube voltage and source mode combinations. Ultimately, the accuracy of iodine quantification was higher for the phantom without an extension ring (RMSE 0.21mg/mL) and did not vary across different levels of iterative reconstruction. The first-generation PCCT allows for accurate iodine quantification over a wide range of iodine concentrations and radiation dose levels. Stable accuracy across iterative reconstruction levels may allow further radiation exposure reductions without affecting quantitative results.

Two-dimensional fetal speckle tracking; a learning curve study for offline strain analysis

Objectives Two-dimensional speckle tracking (2D-STE) strain analysis holds promise for assessing fetal cardiac function. Understand the learning curve before introducing 2D-STE into obstetrics is crucial. This study examined the learning curve for offline analysis of fetal left (LV) and right ventricular (RV) global longitudinal strain (GLS) using 2D-STE. Methods After 2D-STE training, three trainees (Maternal-Fetal Medicine fellow, OBGYN resident and medical student) analyzed 100 fetal heart clips using 2D-STE to calculate LV- and RV-GLS. Intra-class correlation coefficients (ICC) and Bland-Altman plots were compared GLS values across four sets of 25 clips for each trainee against the expert. Repeated measurements analysis compared GLS score differences between expert and trainees over time and among trainees, adjusting p-values with a Bonferroni correction. Results LV-GLS consistency evolved from poor-to-moderate during the first 50 measurements to moderate-to-good during the second 50 for all trainees. RV-GLS consistency evolved from poor-to-moderate during the first 75 measurements to moderate-to-good during the final 25 measurements for the fellow and resident. The student’s RV-GLS consistency was poor during the first 25 measurements, moderate-to good during the second 25 measurements and again poor-to-moderate during the final 50 measurements. Repeated measurements analysis showed a significant decrease in variability of the LV- and RV-GLS score differences between the expert and trainees over time (padj&lt;0.001), which was not significantly different between trainees. Moreover, the mean of those differences were significantly different for all trainees for LV-GLS (padj&lt;0.001) and RV-GLS (padj = 0.029), and did significantly change over time for RV-GLS (padj&lt;0.001) but not for LV-GLS. Conclusions A clear learning effect was observed by the significant decrease in variability of the difference in the score between the expert and trainees over time. The consistency of fetal GLS analysis with 2D-STE was generally found to be moderate to good after 100 measurements in trainees.

Comparative study between swept-source and spectral-domain OCTA for imaging of choroidal neovascularization in age-related macular degeneration

AIM: To compare the differences of choroidal neovascularization (CNV) measurements between swept-source and spectral-domain optical coherence tomography angiography (SS-OCTA and SD-OCTA) in neovascular age-related macular degeneration (nAMD) and the imaging reliability of the two devices. METHODS: Prospective comparative study. SS-OCTA and SD-OCTA were used to scan the same eye with the modes of 3×3 and 6×6 mm2 centered on the neovascularization. Only qualified images were chosen and the border of CNV was manually delineated by two graders independently. The area of CNV (ACNV), vascular perfusion density (PD), and vessel length density (VLD) within the delineation were calculated using Image J. The differences of CNV measurements between the two OCTA devices were compared using Bland-Altman analysis. The agreement between the two graders on the measurements of each device was compared using the intraclass correlation coefficient (ICC). RESULTS: A total of 18 patients (22 eyes) with nAMD were included. The measurements of ACNV, PD, and VLD were 7.247±4.586 and 4.901±3.741 mm2, 43.202±9.636 and 34.904±10.489, 6.339±1.228 and 5.908±1.741 mm-1 for SS-OCTA and SD-OCTA, respectively. The differences between the two devices were 2.346±3.030 mm2 (Z= -3.782, P&amp;#x003C;0.0001), 8.298±14.160 (Z=-2.419, P=0.016), and 0.431±2.114 mm-1 (Z=-0.828, P=0.408) for ACNV, PD and VLD, respectively. The ICC between two graders were 0.893 (P&amp;#x003C;0.001), 0.902 (P&amp;#x003C;0.001), 0.885 (P&amp;#x003C;0.001) for ACNV, PD, VLD in SS-OCTA, and 0.971 (P&amp;#x003C;0.001), 0.976 (P&amp;#x003C;0.001), 0.973 (P&amp;#x003C;0.001) in SD-OCTA, respectively. CONCLUSION: Both OCTA devices have high imaging reliability. Compared with SD-OCTA, SS-OCTA has a larger ACNV measurements, but doesn't show better resolution of internal vessels of CNV and well signal strength.

Analytical interference on measurement of immunoglobulins in monoclonal gammopathy.

Monoclonal gammopathy has been reported to interfere with several laboratory measurement results. We investigated potential interference in monoclonal gammopathy on immunoglobulin A (IgA), immunoglobulin G (IgG), and immunoglobulin M (IgM) concentrations using three different routine chemistry instruments: Alinity (Abbott Laboratories), Cobas 8000 (Roche Diagnostics) and Optilite (Binding Site) at the Department of Clinical Biochemistry, Aalborg University Hospital, Denmark. Blood samples collected from 216 patients with known monoclonal gammopathy were analyzed on Alinity, Cobas and Optilite. Diagnoses were ascertained from clinical records. Scatter plots with Passing-Bablok regression were used to investigate associations between concentrations of IgA, IgG and IgM measured with each of the different instruments. Furthermore, comparison of IgG analyses on Alinity, Optilite and Cobas according to monoclonal IgM concentration was explored with Bland-Altman plots. A total of 81 patients were identified with IgM type monoclonal gammopathy and 8 of these patients (10%) had analytical interference as reflected by more than 25% decrease in the level of IgG measured on Alinity as compared to Optilite and Cobas. All blood samples with interference on IgG measurement using Alinity were from patients with lymphoplasmacytic lymphoma/Waldenströms macroglobulinemia and all of them had monoclonal IgM concentrations above 10 g/L. This study identified a source of interference from IgM monoclonal gammopathy on IgG measurement performed using Alinity. The interferences caused falsely low results of IgG which is important to recognize to ensure proper patient management.

Accuracy of self-reported height, weight, and waist circumference in poor, rural areas of China

Objectives There are differing opinions and findings about the accuracy of self-reported data. This study sought to assess the accuracy of self-reported height, weight, and waist circumference (WC) data among adult residents in poor, rural areas of China. Methods Multi-stage stratified cluster random sampling was used to sample rural adult residents in Jinzhai County. Intraclass correlations (ICCs), Bland-Altman plots with limits of agreements (LOAs), and Cohen’s kappa were used to examine the accuracy of self-reported data. Multiple linear regression was used to explore the effect of demographic and socioeconomic variables. Results Height was over-reported by an average of 0.67 cm, weight and WC were both under-reported, by an average of 0.004 kg and 1.09 cm, respectively. The ICC for height was 0.92, the ICC for weight was 0.93, and the ICC for WC was 0.93. Bland-Altman plots showed no trend in variability with increasing height, weight, and WC, but 95% of the LOAs were wide, especially for WC. The percentage agreement (kappa) for BMI was 82.10% (0.71), and the percentage agreement for WC was 83.56% (0.66). Overall, obesity, overweight, and increased WC were underestimated by 0.56%, 2.64%, and 6.89%, respectively. Assessments of which demographic and socioeconomic factors were associated with statistically significant differences between self-reported and measured data showed that education (junior school vs. primary or below: β = −0.56, 95% CI [−1.01 to −0.11]) and occupation (others vs. professionals: β = 2.16, 95% CI [0.62–3.70]) were associated with differences between measured and self-reported height; occupation (industrial and commercial service vs. professionals: β = 1.57, 95% CI [0.52–2.61]) was associated with differences between measured and self-reported weight; and gender (women vs. men: β = −1.74, 95% CI [−2.51 to −0.97]) and age (60– vs. 18–44: β = −1.62, 95% CI [−2.88 to −0.36]) were associated with differences between measured and self-reported WC. Conclusions Self-reported height and weight were shown to be reliable in poor, rural areas of China, but self-reported WC should be used with caution. To improve the accuracy of self-reported data, certain subgroups should be targeted for educational interventions.

Comparative assessment of breast volume using a smartphone device versus MRI.

Assessment of breast volume has a relevance for aesthetic surgery and for the prevention and prediction of breast diseases. This study investigated breast volume measurements using a three-dimensional (3D) body surface scanner integrated in a smartphone device in comparison with magnetic resonance imaging (MRI) scans. Breast volume was assessed for 22 women who underwent routine MRI imaging. 3D surface images were acquired using a smartphone's digital texture camera (iPhone 11 Pro Max, Apple, California, USA, 2019). Breast volumes were manually outlined and calculated by two independent investigators using a 3D software tool (Meshmixer 3.5, Autodesk, Inc., 2018). Volume assessments from MRI images were performed by a radiologist using Syngo.via (Siemens Healthcare, Erlangen, Germany, VB50). The agreement between both methods and the inter-observer agreement was calculated with the concordance correlation coefficients and analysed with Bland-Altman plots. The mean breast volume as determined by MRI volumetry was 771.0ml on the left side and 763.9ml on the right side. Utilizing the 3D body surface volume assessment method, the mean breast volume was measured as 660.3ml (observer A) and 616.8ml (observer B) on the left side, and 701.9ml (observer A) and 638.6ml (observer B) on the right side. Although a high correlation was observed, differences in volume measurements appeared more pronounced in cases of larger breast volume. Smartphone-based 3D assessment of breast volume sufficiently agreed with MRI-based breast volume. This new technique could be used for cosmetic breast assessments in a surgical context and possibly in breast cancer risk studies assessing breast volume as outcome parameters.

Evaluating sagittal condylar inclination: a comparative analysis of various digital workflow measures.

This study aims to compare sagittal condylar inclination (SCI) measurements derived from three workflows: intraoral scan (IOS) aligned with cone-beam computed tomography (CBCT), IOS aligned with facial scan (FS), and a jaw motion analyzer (JMA) system, in a cohort of young individuals with established normal occlusion. Additionally, the study aims to identify sources contributing to variance in these measurement approaches. Twenty-four healthy individuals exhibiting normal occlusion were enrolled in this clinical trial. The SCI was delineated using a virtual articulator (VA) by aligning IOS with both CBCT and FS, creating two distinct workflows labeled CBCT-IOS and FS-IOS, respectively. Concurrently, SCI measurements were also acquired using a JMA. The normality of data distribution for the difference in bilateral SCI measurements within each workflow was tested using the Shapiro-Wilk test. Depending on the outcomes of this test, we utilized either a paired-sample T-test or Wilcoxon test for bilateral SCI comparisons. The inter-workflow differences were assessed using the Kruskal-Wallis H test. Bland-Altman plots were assess the interchangeability and consistency across each pair of digital methods and to evaluate the aggregate consistency among the trio of digital approaches. The analysis revealed that the CBCT-IOS workflow yielded the lowest average SCI measurements, whereas the JMA workflow produced the highest values. No significant differences were found in the SCI measurements between the left and right sides obtained by CBCT-IOS and JMA (P > .05), with the exception of the FS-IOS workflow (P = .002). Additionally, inter-flow comparisons revealed no significant differences in SCI measurements (P > .05), except when contrasting the SCI as measured by CBCT-IOS and JMA (P = .0131). The Bland-Altman plots demonstrated a high degree of consistency and 95% limits of agreement across the three digital workflows. SCI measurements obtained from the three digital workflows exhibit a high degree of consistency and are interchangeable, affirming their clinical applicability for precise SCI assessment in young individuals with normal occlusion.

Comparison of Different 3D Surface Registration-Based Methods to Assess Facial Asymmetry

Background/Objectives: Facial asymmetry is gaining an increasing diagnostic interest in many clinical contexts. Several three-dimensional surface-based methods have been proposed for its assessment; however, they might provide non-equivalent data. Since there is a lack of comparative studies in these terms, this study aims to compare three methods for assessing the asymmetry of the face and facial thirds, thus addressing whether the potential differences can be considered clinically acceptable or not. Methods: Two ‘maxillofacial’ methods based on the trigeminal nerve distribution and one ‘orthodontic’ method based on reference horizontal planes were used to identify the facial thirds on 3D facial models of 80 Italian healthy adults to calculate the asymmetry of the face, and the upper, middle, and lower thirds of the face differently selected by each method. As a measure of asymmetry, the Root Mean Square value was calculated through a mirroring surface-based registration. Intra- and inter-operator reliability was verified for each method. Differences and interchangeability between the methods were tested, respectively, by two-way repeated measures ANOVA (Analysis of Variance) and Bland–Altman and Similarity Percentage model analysis. Additionally, the time required to perform each method was assessed. Results: All methods demonstrated excellent intra- and inter-operator reliability. While the ANOVA analysis found significant differences (p &lt; 0.001) for the majority of facial Regions of Interest between each method, the Bland–Altman analysis revealed that the differences were clinically acceptable (&lt;0.50 mm) for all facial regions between the trigeminal methods, and for the face and the upper third of the face between the orthodontic method, which was revealed to be faster, and the trigeminal ones. The additional similarity percentage model provided visual support for the complete interchangeability of the two trigeminal methods, as evidenced by the lower Coefficient of Variation value. Conclusions: There is no best method for assessing facial asymmetry that applies to all types of clinical settings, as we have shown that different methods may not be completely interchangeable. However, we suggest that the methods based on the trigeminal subdivision can be used interchangeably in contexts where the morpho-functional analysis of maxillofacial regions with different embryological origins is considered. Thus, the clinical setting imposes the choice of one method over another and, as we have pointed out, the consequent comparison of data with those obtained with methods whose interchangeability has been demonstrated.

AI-BASED AUTOMATED VARUS/VALGUS ALIGNMENT MEASUREMENT IN STANDARD KNEE RADIOGRAPHS

IntroductionAccurate assessment of alignment in pre-operative and post-operative knee radiographs is important for planning and evaluating knee replacement surgery. Existing methods predominantly rely on manual measurements using long-leg radiographs, which are time-consuming to perform and are prone to reliability errors. In this study, we propose a machine-learning-based approach to automatically measure anatomical varus/valgus alignment in pre-operative and post-operative standard AP knee radiographs.MethodWe collected a training dataset of 816 pre-operative and 457 one-year post-operative AP knee radiographs of patients who underwent knee replacement surgery. Further, we have collected a separate distinct test dataset with both pre-operative and one-year post-operative radiographs for 376 patients. We manually outlined the distal femur and the proximal tibia/fibula with points to capture the knee joint (including implants in the post-operative images). This included point positions used to permit calculation of the anatomical tibiofemoral angle. We defined varus/valgus as negative/positive deviations from zero. Ground truth measurements were obtained from the manually placed points. We used the training dataset to develop a machine-learning-based automatic system to locate the point positions and derive the automatic measurements. Agreement between the automatic and manual measurements for the test dataset was assessed by intra-class correlation coefficient (ICC), mean absolute difference (MAD) and Bland-Altman analysis.ResultAnalysing the agreement between the manual and automated measurements, ICC values were excellent pre-/post-operatively (0.96, CI: 0.94-0.96) / (0.95, CI: 0.95-0.96). Pre-/post-operative MAD values were 1.3°±1.4°SD / 0.7°±0.6°SD. The Bland-Altman analysis showed a pre-/post-operative mean difference (bias) of 0.3°±1.9°SD/-0.02°±0.9°SD, with pre-/post-operative 95% limits of agreement of ±3.7°/±1.8°, respectively.ConclusionThe developed machine-learning-based system demonstrates high accuracy and reliability in automatically measuring anatomical varus/valgus alignment in pre-operative and post-operative knee radiographs. It provides a promising approach for automating the measurement of anatomical alignment without the need for long-leg radiographs.AcknowledgementsThis research was funded by the Wellcome Trust [223267/Z/21/Z].

Agreement of intraocular pressure measurement by scleral Schiotz and Goldmann applanation tonometer.

In this cross-sectional observational study, IOP was measured by GAT on the cornea and Schiotz tonometer on the temporal sclera. Axial length and central corneal thickness (CCT) were noted. IOP was then estimated from SS IOP as eGAT using a predictive formula. Agreement of IOP corrected for CCT (cGAT) with eGAT and SS IOP were assessed. The effects of age, axial length, refraction, CCT, gender, and ocular and systemic comorbidity on measured IOP were also assessed. The study included 155 patients with a mean age of 54.27 ± 10.02 years. Mean IOP measured by GAT and scleral Schiotz were 16.58 ± 2.76mm Hg and 16.10 ± 2.96mm Hg, respectively. The mean IOP by cGAT and eGAT were 16.70 ± 2.80mm Hg and 17.07 ± 3.10mm Hg, respectively. Both eGAT & SS IOP had good agreement with cGAT on the Bland-Altmann plot (p = 0.96 & 0.51, respectively). Further, SS IOP showed good agreement even with GAT IOP (p = 0.78). Age, axial length, refraction, central corneal thickness, gender, and ocular and systemic comorbidity did not show significant correlation with IOP measurement. Estimated GAT IOP showed good agreement with measured GAT values. SS IOP also agreed well with GAT IOP. Clinical significance IOP measurement on the sclera using Schiotz can be used as an alternative to GAT.

Impact of proxymetacaine on the dynamics of cyclopentolate in White 6- to 7-year-olds.

This study compared the efficacy of cyclopentolate hydrochloride at 10-, 20- and 30-min post-instillation in White 6- to 7-year-olds, with and without prior instillation of proxymetacaine hydrochloride. The primary aim was to determine if accurate autorefraction values can be obtained sooner than the current standard of 30-min post-cycloplegia. The secondary aim was to investigate whether proxymetacaine hydrochloride enhances the efficiency of cyclopentolate. Participants were 112 White 6- to 7-year-olds from the Child Eye Health Study. The right eye received 0.5% proxymetacaine hydrochloride and 1.0% cyclopentolate hydrochloride, and the left eye received only 1.0% cyclopentolate hydrochloride. Non-cycloplegic and cycloplegic refractive error (at 0, 10, 20 and 30 min) was measured using a binocular, open-field autorefractometer. Data were analysed through paired t-tests, concordance analysis, linear regression, equivalence testing and Bland-Altman analysis, using the 95% limits of agreement. Mean spherical equivalent refraction (SER) (SD) in the right eye at 0-, 10-, 20- and 30-min post-instillation was 0.62 (1.45) D, 1.52 (1.80) D, 1.64 (1.81) D and 1.72 (1.80) D, respectively. Mean left eye SER (SD) were 0.68 (1.24) D, 1.42 (1.66) D, 1.56 (1.66) D and 1.68 (1.72) D, respectively. Bland-Altman analysis showed a high level of agreement, and equivalence testing confirmed that there was no clinically significant difference in SER at 20 and 30 min in both eyes (within ±0.50 D), with mean differences of 0.08 (0.23) D in the right eye and 0.13 (0.30) D in the left eye (p = 0.21). However, SER at 10 and 30 min were equivalent in the right eye only. Accurate autorefraction values can be obtained 20-min post-instillation of 1.0% cyclopentolate in white children aged 6-7 years, potentially reducing clinical testing times. Proxymetacaine pre-instillation allows for reliable measurements as early as 10-min post-instillation of cyclopentolate. Further research is needed to validate these findings in non-White populations and to determine the safe discharge time post-proxymetacaine instillation.

Accuracy and reliability of accelerometer-based pedometers in step counts during walking, running, and stair climbing in different locations of attachment.

This study aimed to investigate the accuracy and reliability of accelerometer-based pedometers placed on the wrist, waist, and shoe's midsole during walking, running, and stair climbing. Twenty healthy adults were recruited. Steps were recorded by the pedometers and visually assessed from simultaneously recorded video to evaluate the accuracy of each pedometer in different locations of attachment. One week later, steps were recorded again by the pedometers only to evaluate the reliability of each pedometer in different locations of attachment. The wrist-worn pedometer presented significantly greater error scores compared to the midsole-worn pedometer during walking (p < 0.001), running (p = 0.006), and stair climbing (p = 0.003). Additionally, mean absolute precent error and Bland-Altman plots indicated that the pedometer worn in the midsole was most accurate for running and stair climbing, followed by waist-worn and wrist-worn pedometers. Furthermore, the midsole-worn and waist-worn pedometers showed strong reliability during walking and running, but only the midsole-worn pedometer presented acceptable reliability during stair climbing. The pedometer's position impacts the accuracy and reliability of step counts, especially for walking and stair climbing. Embedding the pedometer into the midsole seems an effective approach to improve the accuracy and reliability of step counts.