Reporting Standards for a Bland-Altman Agreement Analysis: A Review of Methodological Reviews

Reproducibility of arterial spin labeling cerebral blood flow image processing: A report of the ISMRM open science initiative for perfusion imaging (OSIPI) and the ASL MRI challenge

PURPOSE

Arterial spin labeling (ASL) is a widely used contrast-free MRI method for assessing cerebral blood flow (CBF). Despite the generally adopted ASL acquisition guidelines, there is still wide variability in ASL analysis. We explored this variability through the ISMRM-OSIPI ASL-MRI Challenge, aiming to establish best practices for more reproducible ASL analysis.

METHODS

Eight teams analyzed the challenge data, which included a high-resolution T1-weighted anatomical image and 10 pseudo-continuous ASL datasets simulated using a digital reference object to generate ground-truth CBF values in normal and pathological states. We compared the accuracy of CBF quantification from each team's analysis to the ground truth across all voxels and within predefined brain regions. Reproducibility of CBF across analysis pipelines was assessed using the intra-class correlation coefficient (ICC), limits of agreement (LOA), and replicability of generating similar CBF estimates from different processing approaches.

RESULTS

Absolute errors in CBF estimates compared to ground-truth synthetic data ranged from 18.36 to 48.12 mL/100 g/min. Realistic motion incorporated into three datasets produced the largest absolute error and variability between teams, with the least agreement (ICC and LOA) with ground-truth results. Fifty percent of the submissions were replicated, and one produced three times larger CBF errors (46.59 mL/100 g/min) compared to submitted results.

CONCLUSIONS

Variability in CBF measurements, influenced by differences in image processing, especially to compensate for motion, highlights the significance of standardizing ASL analysis workflows. We provide a recommendation for ASL processing based on top-performing approaches as a step toward ASL standardization.

Psychometric Properties of General Oral Health Assessment Index Across Ages: COSMIN Systematic Review

OBJECTIVES

To systematically review the psychometric properties of the Geriatric Oral Health Assessment Index (GOHAI) across age groups using the COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) methodology.

METHODS

Data: English peer-reviewed articles reporting studies of the development, translation, or validation of GOHAI.

SOURCES

PubMed, Web of Science, and EMBASE from Jan 1990 until December 31, 2023. Methodological evaluation: based on COSMIN methodology. The results are presented overall and for 4 age groups (≥60 years, all ages, <60 years, ≤45 years). Structural validity was summarized qualitatively. Internal consistency and reliability were synthesized via random-effects meta-analysis of T-transformed Cronbach α values, and Fisher's Z transformed correlation coefficients. Construct validity and responsiveness were assessed using effect sizes.

RESULTS

Four hundred ninety-seven records were identified, 72 underwent full-text assessment, resulting in 60 included reports. Structural validity was inconsistent across all age groups and overall. Internal consistency was sufficient with overall α = 0.81, and high evidence quality. Test-retest reliability was consistently sufficient across age groups with overall r = 0.84. For construct validity 361 hypotheses were assessed (37.4% for convergent-, 62.6% for known-groups validity). The percentage of confirmed hypotheses in ≥60-years, all ages, <60-years and ≤45-years were 75.5%, 66.7%, 78.9%, and 88.9%, respectively. Responsiveness was not assessed in the <60-years and ≤45-years age groups, leading to indeterminate overall rating with very low evidence quality.

CONCLUSIONS

This review affirms that GOHAI has sufficient psychometric properties as an oral health-related quality of life instrument in various age groups, but its responsiveness is scarcely researched and its utility for individual-level follow-up is limited. The measurement properties of oral health-related quality of life tools must be scrutinized in the changing demands of personalized and value-based dental care. (PROSPERO registration: CRD42022384132).

Cervical Multifidus Stiffness Assessment in Individuals with and without Unilateral Chronic Neck Pain: An Inter-Examiner Reliability Study

This study aimed to evaluate the inter-examiner reliability of shear wave elastography (SWE) for measuring cervical multifidus (CM) muscle stiffness in asymptomatic controls and patients with chronic neck pain. A longitudinal observational study was conducted to assess the diagnostic accuracy of a procedure. SWE images, following a detailed procedure previously tested, were acquired by two examiners (one novice and one experienced) to calculate the shear wave speed (SWS) and Young's modulus. The painful side was examined for the experimental cases while the side examined in the control group was selected randomly. Data analyses calculated the intra-class correlation coefficients (ICCs), absolute errors between examiners, standard errors of measurement, and minimal detectable changes. A total of 125 participants were analyzed (n = 54 controls and n = 71 cases). The Young's modulus and SWS measurements obtained by both examiners were comparable within the asymptomatic group (both, p > 0.05) and the chronic neck pain group (both, p > 0.05). Nonetheless, a notable distinction was observed in the absolute error between examiners for shear wave speed measurements among patients with neck pain, where a significant difference was registered (p = 0.045), pointing to a sensitivity in measurement consistency affected by the presence of chronic neck pain. ICCs demonstrated moderate-to-good reliability across both groups, with ICC values for asymptomatic individuals reported as >0.8. Among the chronic neck pain patients, ICC values were slightly lower (>0.780). The study revealed moderate-to-good consistency, highlighting the practicality and generalizability of SWE.

Using point-of-care devices to examine covariation among blood nutritional-physiological parameters and their relationships with poxvirus infection, habitat urbanization, and male plumage coloration in house finches (Haemorhous mexicanus)

The development of inexpensive and portable point-of-care devices for measuring nutritional physiological parameters from blood (e.g., glucose, ketones) has accelerated our understanding and assessment of real-time variation in human health, but these have infrequently been tested or implemented in wild animals, especially in relation to other key biological or fitness-related traits. Here we used point-of-care devices to measure blood levels of glucose, ketones, uric acid, and triglycerides in free-ranging house finches (Haemorhous mexicanus)-a common songbird in North America that has been well-studied in the context of urbanization, nutrition, health, and sexual selection-during winter and examined (1) repeatability of these methods for evaluating blood levels in these wild passerines, (2) intercorrelations among these measurements within individuals, (3) how blood nutritional-physiology metrics related to a bird's body condition, habitat of origin (urban vs. suburban), poxvirus infection, and sex; and (4) if the expression of male sexually selected plumage coloration was linked to any of the nutritional-physiological metrics. All blood-nutritional parameters were repeatable. Also, there was significant positive covariation between concentrations of circulating triglycerides and glucose and triglycerides and uric acid. Urban finches had higher blood glucose concentrations than suburban finches, and pox-infected individuals had lower blood triglyceride concentrations than uninfected ones. Last, redder males had higher blood glucose, but lower uric acid levels. These results demonstrate that point-of-care devices can be useful, inexpensive ways of measuring real-time variation in the nutritional physiology of wild birds.

Validity and reliability of the 2-min step test in individuals with stroke and lower-limb musculoskeletal disorders

Introduction

We investigated the reliability and validity of the 2-min step test (2MST) for assessing the exercise endurance of individuals with stroke and lower-limb musculoskeletal disorders.

Participants and methods

The participants were 39 individuals with stroke and 42 with lower-limb musculoskeletal disorders (mainly hip fractures) from the convalescent rehabilitation wards of four hospitals. The concurrent validity and congruence between the 2MST and the 6-min walk test (6MWT) and construct validity by hypotheses testing, including mobility and lower limb muscle strength, were also confirmed. A subset of participants (stroke-group, n = 15; musculoskeletal-group, n = 19) underwent a retest 2MST for our evaluation of relative and absolute reliability using the intraclass correlation coefficient (ICC1,1) and Bland-Altman plot.

Results

Both groups showed a moderate correlation between the 2MST and 6MWT (ρ = 0.55-0.60), but the congruence was not sufficient. The 6MWT was correlated with mobility in both groups and with muscle strength in the stroke group, whereas the 2MST did not show a significant correlation with mobility. The relative reliability was excellent in both groups (ICC1,1 > 0.9). In terms of absolute reliability, the width of the limit of agreement was 18.8% for the stroke group and 15.4% for the musculoskeletal group, relative to their respective sample means of 2MST. A fixed bias was identified in the stroke group, in which step counts increased by 6.5 steps upon retesting.

Discussion

Our analyses revealed that the 2MST is a valid and reliable tool for assessing the exercise endurance of individuals with stroke or lower-limb musculoskeletal disorders. However, it is necessary to validate the absolute reliability observed herein by using a larger sample size. In addition, when assessing the exercise endurance of individuals with stroke, it may be necessary to consider the potential bias of an increased step count during retesting.

Repeatability of diffusion-based stiffness prediction - A healthy volunteer study

INTRODUCTION

The study investigated the repeatability of brain diffusion-based stiffness prediction (DWIstiff) in healthy volunteers.

METHODS

Thirty-one healthy volunteers were examined with DWIstiff using two different sets of b-values: b200-1500 s/mm2 (DWIstiff, 1500) and b200-1000 s/mm2 (DWIstiff, 1000). Each b-value set was scanned twice per imaging session without repositioning the participants. DWIstiff images were reconstructed from each set. Two observers delineated regions of interest (ROIs) on each DWIstiff image. The repeatability coefficient (RC), coefficient of variation (CV), inter- and intraobserver agreement were calculated.

RESULTS

After excluding three participants due to image artifacts, the study included twenty-eight volunteers (mean age (range)) 37 years (24-62), 10 males, 18 females). For DWIstiff, 1500, the lowest and the highest RCs were in the parietal lobe (0.52) and respectively the brain stem (1.17). The lowest RC for DWIstiff, 1000 was in the frontal lobe (0.42) and the highest in the brain stem (1.58). The CV for whole brain measurements was 3.83 % for DWIstiff, 1500 and 4.93 % for DWIstiff, 1000. The Bland‒Altman (BA) limits of agreement (LoA) for the intraobserver agreement of DWIstiff, 1500 were -0.90 to 1.06 and respectively -0.78 to 0.88 for DWIstiff, 1000. Regarding interobserver agreement, the LoA were -0.85 to 0.94 for DWIstiff, 1500 and -0.61 to 0.66 for DWIstiff, 1000.

CONCLUSION

DWIstiff is a precise technique with some observer dependence. Repeatability is higher for DWIstiff, 1000 s/mm2 than for DWIstiff 1500 s/mm2.

IMPLICATIONS FOR PRACTICE

Our findings suggest that DWIstiff can reliably detect stiffness changes larger than 4.93 % in healthy volunteers. Further studies should investigate whether the repeatability of DWIstiff may be affected by the presence of pathology such as a brain tumor.

Clinical assessment of an AI tool for measuring biventricular parameters on cardiac MR

Introduction

Cardiac magnetic resonance (CMR) is of diagnostic and prognostic value in a range of cardiopulmonary conditions. Current methods for evaluating CMR studies are laborious and time-consuming, contributing to delays for patients. As the demand for CMR increases, there is a growing need to automate this process. The application of artificial intelligence (AI) to CMR is promising, but the evaluation of these tools in clinical practice has been limited. This study assessed the clinical viability of an automatic tool for measuring cardiac volumes on CMR.

Methods

Consecutive patients who underwent CMR for any indication between January 2022 and October 2022 at a single tertiary centre were included prospectively. For each case, short-axis CMR images were segmented by the AI tool and manually to yield volume, mass and ejection fraction measurements for both ventricles. Automated and manual measurements were compared for agreement and the quality of the automated contours was assessed visually by cardiac radiologists.

Results

462 CMR studies were included. No statistically significant difference was demonstrated between any automated and manual measurements (p > 0.05; independent T-test). Intraclass correlation coefficient and Bland-Altman analysis showed excellent agreement across all metrics (ICC > 0.85). The automated contours were evaluated visually in 251 cases, with agreement or minor disagreement in 229 cases (91.2%) and failed segmentation in only a single case (0.4%). The AI tool was able to provide automated contours in under 90 s.

Conclusions

Automated segmentation of both ventricles on CMR by an automatic tool shows excellent agreement with manual segmentation performed by CMR experts in a retrospective real-world clinical cohort. Implementation of the tool could improve the efficiency of CMR reporting and reduce delays between imaging and diagnosis.

Surgical prioritization based on decision model outcomes is not sensitive to differences between the health-related quality of life values estimates of physicians and citizens

PURPOSE

Decision models can be used to support allocation of scarce surgical resources. These models incorporate health-related quality of life (HRQoL) values that can be determined using physician panels. The predominant opinion is that one should use values obtained from citizens. We investigated whether physicians give different HRQoL values to citizens and evaluate whether such differences impact decision model outcomes.

METHODS

A two-round Delphi study was conducted. Citizens estimated HRQoL of pre- and post-operative health states for ten surgeries using a visual analogue scale. These values were compared using Bland-Altman analysis with HRQoL values previously obtained from physicians. Impact on decision model outcomes was evaluated by calculating the correlation between the rankings of surgeries established using the physicians' and the citizens' values.

RESULTS

A total of 71 citizens estimated HRQoL. Citizens' values on the VAS scale were - 0.07 points (95% CI - 0.12 to - 0.01) lower than the physicians' values. The correlation between the rankings of surgeries based on citizens' and physicians' values was 0.96 (p < 0.001).

CONCLUSION

Physicians put higher values on health states than citizens. However, these differences only result in switches between adjacent entries in the ranking. It would seem that HRQoL values obtained from physicians are adequate to inform decision models during crises.

Agreement of zero-heat-flux thermometry with the oesophageal and tympanic core temperature measurement in patient receiving major surgery

To identify and prevent perioperative hypothermia, most surgical patients require a non-invasive, accurate, convenient, and continuous core temperature method, especially for patients undergoing major surgery. This study validated the precision and accuracy of a cutaneous zero-heat-flux thermometer and its performance in detecting intraoperative hypothermia. Adults undergoing major non-cardiac surgeries with general anaesthesia were enrolled in the study. Core temperatures were measured with a zero-heat-flux thermometer, infrared tympanic membrane thermometer, and oesophagal monitoring at 15-minute intervals. Taking the average value of temperature measured in the tympanic membrane and oesophagus as a reference, we assessed the agreement using the Bland-Altman analysis and linear regression methods. Sensitivity, specificity, and predictive values of detecting hypothermia were estimated. 103 patients and one thousand sixty-eight sets of paired temperatures were analyzed. The mean difference between zero-heat-flux and the referenced measurements was -0.03 ± 0.25 °C, with 95% limits of agreement (-0.52 °C, 0.47 °C) was narrow, with 94.5% of the differences within 0.5 °C. Lin's concordance correlation coefficient was 0.90 (95%CI 0.89-0.92). The zero-heat-flux thermometry detected hypothermia with a sensitivity of 82% and a specificity of 90%. The zero-heat-flux thermometer is in good agreement with the reference core temperature based on tympanic and oesophagal temperature monitoring in patients undergoing major surgeries, and appears high performance in detecting hypothermia.

Is it necessary to perform measurement-based patient-specific quality assurance for online adaptive radiotherapy with Elekta Unity MR-Linac?

This study aimed to investigate the necessity of measurement-based patient-specific quality assurance (PSQA) for online adaptive radiotherapy by analyzing measurement-based PSQA results and calculation-based 3D independent dose verification results with Elekta Unity MR-Linac. There are two workflows for Elekta Unity enabled in the treatment planning system: adapt to position (ATP) and adapt to shape (ATS). ATP plans are those which have relatively slighter shifts from reference plans by adjusting beam shapes or weights, whereas ATS plans are the new plans optimized from the beginning with probable re-contouring targets and organs-at-risk. PSQA gamma passing rates were measured using an MR-compatible ArcCHECK diode array for 78 reference plans and corresponding 208 adaptive plans (129 ATP plans and 79 ATS plans) of Elekta Unity. Subsequently, the relationships between ATP, or ATS plans and reference plans were evaluated separately. The Pearson's r correlation coefficients between ATP or ATS adaptive plans and corresponding reference plans were also characterized using regression analysis. Moreover, the Bland-Altman plot method was used to describe the agreement of PSQA results between ATP or ATS adaptive plans and reference plans. Additionally, Monte Carlo-based independent dose verification software ArcherQA was used to perform secondary dose check for adaptive plans. For ArcCHECK measurements, the average gamma passing rates (ArcCHECK vs. TPS) of PSQA (3%/2 mm criterion) were 99.51% ± 0.88% and 99.43% ± 0.54% for ATP and ATS plans, respectively, which were higher than the corresponding reference plans 99.34% ± 1.04% (p < 0.05) and 99.20% ± 0.71% (p < 0.05), respectively. The Pearson's r correlation coefficients were 0.720 between ATP and reference plans and 0.300 between ATS and reference plans with ArcCHECK, respectively. Furthermore, >95% of data points of differences between both ATP and ATS plans and reference plans were within ±2σ (standard deviation) of the mean difference between adaptive and reference plans with ArcCHECK measurements. With ArcherQA calculation, the average gamma passing rates (ArcherQA vs. TPS) were 98.23% ± 1.64% and 98.15% ± 1.07% for ATP and ATS adaptive plans, separately. It might be unnecessary to perform measurement-based PSQA for both ATP and ATS adaptive plans for Unity if the gamma passing rates of both measurements of corresponding reference plans and independent dose verification of adaptive plans have high gamma passing rates. Periodic machine QA and verification of adaptive plans were recommended to ensure treatment safety.

Sound-based cough peak flow estimation in patients with neuromuscular disorders

INTRODUCTION/AIMS

Cough impairment is common in individuals with neuromuscular disorders and is associated with respiratory infections and shorter survival. Cough strength is assessed by measuring cough peak flow (CPF) using a flow meter, but this method requires a complex device setup and trained staff. The aim of the study is to evaluate the reliability of a smartphone app to estimate CPF based on cough sounds in a cohort of individuals with neuromuscular disorders.

METHODS

Individuals with neuromuscular disorders underwent CPF measurement with a flow meter and a smartphone app. A CPF <270 L/min was considered abnormal.

RESULTS

Of the 50 patients studied, 26 had amyotrophic lateral sclerosis (52%), 15 had hereditary myopathies (30%), and 9 had myasthenia gravis (18%). The intraclass correlation coefficient (ICC) between the CPF measured with a flow meter and CPF estimated with cough sounds was 0.774 (p < .001) even if the patients had orofacial weakness (ICC = 0.806, p < .001). The smartphone app had 94.4% sensitivity and 100% specificity to detect patients with CPF of less than 270 L/min.

DISCUSSION

Our findings suggest that sounds measured with a smartphone app provide a reliable estimate of CPF in patients with neuromuscular disorders, even in the presence of with orofacial weakness. This may be a convenient way to monitor respiratory involvement in patients with neuromuscular disorders, but larger studies of more diverse patient cohorts are needed.

Accuracy validation of a wearable IMU-based gait analysis in healthy female

OBJECTIVE

The aim of this study was to assess the accuracy and test-retest reliability of a wearable inertial measurement unit (IMU) system for gait analysis in healthy female compared to a gold-standard optoelectronic motion capture (OMC) system.

METHODS

In our study, we collected data from 5 healthy young females. Participants were attached with markers from both the OMC system and the IMU system simultaneously. Data was collected when participants walked on a 7 m walking path. Each participant performed 50 repetitions of walking on the path. To ensure the collection of complete gait cycle data, a gait cycle was considered valid only if the participant passed through the center of the walking path at the same time that the OMC system detected a valid marker signal. As a result, 5 gait cycles that met the standards of the OMC system were included in the final analysis. The stride length, cadence, velocity, stance phase and swing phase of the spatio-temporal parameters were included in the analysis. A generalized linear mixture model was used to assess the repeatability of the two systems. The Wilcoxon rank-sum test for continuous variables was used to compare the mean differences between the two systems. For evaluating the reliability of the IMU system, we calculated the Intra-class Correlation Coefficient (ICC). Additionally, Bland-Altman plots were used to compare the levels of agreement between the two systems.

RESULTS

The measurements of Spatio-temporal parameters, including the stance phase (P = 0.78, 0.13, L-R), swing phase (P = 0.78, 0.13, L-R), velocity (P = 0.14, 0.13, L-R), cadence (P = 0.53, 0.22, L-R), stride length (P = 0.05, 0.19, L-R), by the IMU system and OMC system were similar. Which suggested that IMU and OMC systems could be used interchangeably for gait measurements. The intra-rater reliability showed an excellent correlation for the stance phase, swing phase, velocity and cadence (Intraclass Correlation Coefficient, ICC > 0.9) for both systems. However, the correlation of stride length was poor (ICC = 0.36, P = 0.34, L) to medium (ICC = 0.56, P = 0.22, R). Additionally, the measurements of IMU systems were repeatable.

CONCLUSIONS

The results of IMU system and OMC system shown good repeatability. Wearable IMU system could analyze gait data accurately. In particular, the measurement of stance phase, swing phase, velocity and cadence showed excellent reliability. IMU system provided an alternative measurement to OMC for gait analysis. However, the measurement of stride length by IMU needs further consideration.

Synthetic Knee MRI T1p Maps as an Avenue for Clinical Translation of Quantitative Osteoarthritis Biomarkers

A 2D U-Net was trained to generate synthetic T1p maps from T2 maps for knee MRI to explore the feasibility of domain adaptation for enriching existing datasets and enabling rapid, reliable image reconstruction. The network was developed using 509 healthy contralateral and injured ipsilateral knee images from patients with ACL injuries and reconstruction surgeries acquired across three institutions. Network generalizability was evaluated on 343 knees acquired in a clinical setting and 46 knees from simultaneous bilateral acquisition in a research setting. The deep neural network synthesized high-fidelity reconstructions of T1p maps, preserving textures and local T1p elevation patterns in cartilage with a normalized mean square error of 2.4% and Pearson's correlation coefficient of 0.93. Analysis of reconstructed T1p maps within cartilage compartments revealed minimal bias (-0.10 ms), tight limits of agreement, and quantification error (5.7%) below the threshold for clinically significant change (6.42%) associated with osteoarthritis. In an out-of-distribution external test set, synthetic maps preserved T1p textures, but exhibited increased bias and wider limits of agreement. This study demonstrates the capability of image synthesis to reduce acquisition time, derive meaningful information from existing datasets, and suggest a pathway for standardizing T1p as a quantitative biomarker for osteoarthritis.

Bland-Altman agreement analysis between CT predicted and surgical peritoneal cancer index in pseudomyxoma peritonei of appendiceal origin

Peritoneal cancer index (PCI) is the surgical variable most commonly used to quantify the extent of peritoneal metastases for pseudomyxoma peritonei (PMP) patients. The present study aimed to investigate the agreement between CT predicted and surgical PCI by the Bland-Altman method for PMP of appendiceal origin. A total of 167 PMP patients of appendiceal origin were included between 2016 and 2021. Bland-Altman analysis was performed for both total PCI and selected PCI (regions 2 + 9-12). After the Bland-Altman plot was drawn, the mean bias and its 95% limit of agreements (LoAs) was quantified. Besides, the correlation coefficients between CT-PCI and surgical PCI were also been calculated. The Bland-Altman plot showed the mean bias ± SD between total CT-PCI and surgical PCI as 0.431 ± 3.005, with the LoAs from - 5.459 to 6.321. There were nine points of difference in total PCI exceeded the 95% LoAs, with the rate of 5.39% (9/167). As for selected CT-PCI, Bland-Altman plot showed the mean bias ± SD between selected CT-PCI and surgical PCI as - 0.287 ± 1.955, with the LoAs from - 4.118 to 3.544. There were ten points of difference in selected PCI exceeded the 95% LoAs, with the rate of 5.99% (10/167). The Spearman's rank correlation coefficient between total CT-PCI and surgical PCI was 0.911, P < 0.001, as for selected CT-PCI and surgical PCI, the coefficient was 0.909, P < 0.001. Although there was a strong correlation for both total and selected CT-PCI with surgical PCI, however, the agreement is still not good in Bland-Altman analysis, which suggested that CT-PCI cannot predict surgical PCI accurately even in professional PMP treatment centers. In brief explanation, CT makes it difficult to distinguish the borderline between tumor tissue and mucus and to detect tumor lesions in the small intestine regions, which caused overestimation or underestimation by CT-PCI. In the future, a multiple linear regression model based on CT-PCI might accurately predict surgical PCI preoperatively.

Impaired sliding between the lower esophageal sphincter and crural diaphragm (esophageal hiatus) in patients with achalasia esophagus

Swallow-related axial shortening of the esophagus results in the formation of phrenic ampulla in normal subjects; whether it is the case in achalasia esophagus is not known. The goal is to study axial shortening of the esophagus and relative movement between the lower esophageal sphincter (LES) and crural diaphragm (CD) in normal subjects and patients with achalasia. A novel method, isoimpedance contour excursion at the lower edger of LES, as a marker of axial esophageal shortening was validated using X-ray fluoroscopy (n = 5) and used to study axial shortening and separation between the LES and CD during peristalsis in normal subjects (n = 15) and patients with achalasia type 2 esophagus (n = 15). Abdominal CT scan images were used to determine the nature of tissue in the esophageal hiatus of control (n = 15) and achalasia patients (n = 15). Swallow-induced peristalsis resulted in an axial excursion of isoimpedance contours, which was quantitatively similar to the metal clip anchored to the LES on X-ray fluoroscopy (2.3 ± 1.4 vs. 2.1 ± 1.4 cm with deep inspiration and 2.7 ± 0.6 cm vs. 2.7 ± 0.6 cm with swallow-induced peristalsis). Esophageal axial shortening with swallows in patients with achalasia was significantly smaller than normal (1.64 ± 0.5 cm vs. 3.59 ± 0.4 cm, P < 0.001). Gray-level matrix analysis of CT images suggests more "fibrous" and less fat in the hiatus of patients with achalasia. Lack of sliding between the LES and CD explains the low prevalence of hiatus hernia, and low compliance of the LES in achalasia esophagus, which likely plays a role in the pathogenesis of achalasia.NEW & NOTEWORTHY Swallow-related axial shortening of the esophagus is reduced, and there is no separation between the lower esophageal sphincter and crural diaphragm (CD) with swallowing in patients with achalasia esophagus. Fat in the hiatal opening of the esophagus appears to be replaced with fibrous tissue in patients with achalasia, resulting in tight anchoring between the LES and CD. The above findings explain low prevalence of hiatus hernia and the low compliance of the LES in achalasia esophagus.

Total energy expenditure assessed by 24-h whole-room indirect calorimeter in patients with colorectal cancer: baseline findings from the PRIMe study

BACKGROUND

Total energy expenditure (TEE) determines energy requirements, but objective data in patients with cancer are limited.

OBJECTIVES

We aimed to characterize TEE, investigate its predictors, and compare TEE with cancer-specific predicted energy requirements.

METHODS

This cross-sectional analysis included patients with stages II-IV colorectal cancer from the Protein Recommendation to Increase Muscle (PRIMe) trial. TEE was assessed by 24-h stay in a whole-room indirect calorimeter before dietary intervention and compared with cancer-specific predicted energy requirements (25-30 kcal/kg). Generalized linear models, paired-samples t tests, and Pearson correlation were applied.

RESULTS

Thirty-one patients (56 ± 10 y; body mass index [BMI]: 27.9 ± 5.5 kg/m2; 68% male) were included. Absolute TEE was higher in males (mean difference: 391 kcal/d; 95% CI: 167, 616 kcal/d; P < 0.001), patients with colon cancer (mean difference: 279 kcal/d; 95% CI: 73, 485 kcal/d; P = 0.010), and patients with obesity (mean difference: 393 kcal/d; 95% CI: 182, 604 kcal/d; P < 0.001). Appendicular lean soft tissue (β: 46.72; 95% CI: 34.27, 59.17; P < 0.001) and tumor location (colon-β: 139.69; 95% CI: 19.44, 259.95; P = 0.023) independently predicted TEE when adjusted for sex. Error between measured TEE and energy requirements predicted by 25 kcal/kg (mean difference: 241 kcal/d; 95% CI: 76, 405 kcal/d; P = 0.010) or 30 kcal/kg (mean difference: 367 kcal/d; 95% CI: 163, 571 kcal/d; P < 0.001) was higher for patients with obesity, and proportional error was observed (25 kcal/kg: r = -0.587; P < 0.001; and 30 kcal/kg: r = -0.751; P < 0.001). TEE (mean difference: 25 kcal/kg; 95% CI: 24, 27 kcal/kg) was below predicted requirements using 30 kcal/kg (-430 ± 322 kcal/d; P < 0.001).

CONCLUSIONS

This is the largest study to assess TEE of patients with cancer using whole-room indirect calorimeter and highlights the need for improved assessment of energy requirements in this population. Energy requirements predicted using 30 kcal/kg overestimated TEE by 1.44 times in a controlled sedentary environment and TEE was outside of the predicted requirement range for most. Special considerations are warranted when determining TEE of patients with colorectal cancer, such as BMI, body composition, and tumor location. This is a baseline cross-sectional analysis from a clinical trial registered at clinicaltrials.gov as NCT02788955 (https://clinicaltrials.gov/ct2/show/NCT02788955).

How Can We Measure Alcohol Outlet Density Around Schools? A Comparison Between Two Buffer-Based Methods

Measuring the density of alcohol outlets around schools is a critical step towards understanding the drivers of drinking among adolescents. Different methodologies have been used in the literature for this purpose, but the implications of using one methodology or another have not been clearly assessed. Our aim was to compare different methods to measure alcohol outlet density and highlight under which characteristics of the environment might be best using each approach. We used Geographic Information Systems to geolocate schools (n = 576) and alcohol outlets (n = 21,732) in Madrid. We defined the density of alcohol outlets as the number of establishments within an area of 400 m around schools measured using two buffering methods: crow flies' and street network distances. We evaluated the agreement between both methods visually and through regression models, including street connectivity, population density, and density of recreational venues as predictors of disagreement. The density of alcohol outlets around schools was higher using crow flies' distances compared to street network distances. The differences between methodologies were wider in areas of higher density of outlets, especially in the downtown areas, where there are higher population density and street connectivity. Our results suggest that the spatial characteristics and morphology of the study area (e.g., street connectivity and population density) should be considered when deciding the methodology to be used to measure alcohol outlet density. Future studies should explore the implications of different exposure measures in their association with drinking prevalence and consumption patterns among different geographical contexts.

Simple assay for quantifying xanthine oxidase activity

This paper reports a sensitive method for assaying xanthine oxidase (XO) enzyme activity. XO produces hydrogen peroxide (H₂O₂) and superoxide anion radicals (O₂^•-), promoting the development of oxidative stress-related diseases, and is inhibited by various plant extracts. XO activity is quantified by incubating enzyme samples with an appropriate xanthine concentration as the substrate. The proposed method requires XO activity to be quantified based on H₂O₂ generation using a 3,3',5,5'-tetramethylbenzidine (TMB)-H₂O₂ system catalyzed by cupric ions. After a 30-minute incubation at 37 °C, sufficient cupric ion and TMB amounts are added. The assay produces optical signals that can be visually recognized or detected with a UV-visible spectrometer. A direct correlation was found between XO activity and the absorbance at 450 nm of the resulting di-imine (dication) yellow product. The proposed method uses sodium azide to prevent catalase enzyme interference. The new assay's function was confirmed using the TMB-XO assay and a Bland-Altman plot. The resulting correlation coefficient was 0.9976. The innovative assay was relatively precise and comparable to the comparison protocols. In conclusion, the presented method is very efficient at measuring XO activity.

Measurement of changes in uterine and fibroid volume during treatment of heavy menstrual bleeding (HMB)

STUDY QUESTION

Does application of an unbiased method for analysis of magnetic resonance (MR) images reveal any effect on uterine or fibroid volume from treatment of heavy menstrual bleeding (HMB) with three 12-week courses of the selective progesterone receptor modulator ulipristal acetate (SPRM-UPA)?

SUMMARY ANSWER

Application of an unbiased method for analysis of MR images showed that treatment of HMB with SPRM-UPA was not associated with a significant reduction in the volume of the uterus or in the volume of uterine fibroids.

WHAT IS KNOWN ALREADY

SPRM-UPA shows therapeutic efficacy for treating HMB. However, the mechanism of action (MoA) is not well understood and there have been mixed reports, using potentially biased methodology, regarding whether SPRM-UPA has an effect on the volume of the uterus and fibroids.

STUDY DESIGN SIZE DURATION

In a prospective clinical study (with no comparator), 19 women with HMB were treated over a period of 12 months with SPRM-UPA and uterine and fibroid size were assessed with high resolution structural MRI and stereology.

PARTICIPANTS/MATERIALS SETTING METHODS

A cohort of 19 women aged 38-52 years (8 with and 11 without fibroids) were treated with three 12-week courses of 5 mg SPRM-UPA given daily, with four weeks off medication in-between treatment courses. Unbiased estimates of the volume of uterus and total volume of fibroids were obtained at baseline, and after 6 and 12 months of treatment, by using the Cavalieri method of modern design-based stereology in combination with magnetic resonance imaging (MRI).

MAIN RESULTS AND THE ROLE OF CHANCE

Bland-Altman plots showed good intra-rater repeatability and good inter-rater reproducibility for measurement of the volume of both fibroids and the uterus. For the total patient cohort, two-way ANOVA did not show a significant reduction in the volume of the uterus after two or three treatment courses of SPRM-UPA (P = 0.51), which was also the case when the groups of women with and without fibroids were considered separately (P = 0.63). One-way ANOVA did not show a significant reduction in total fibroid volume in the eight patients with fibroids (P = 0.17).

LIMITATIONS REASONS FOR CAUTION

The study has been performed in a relatively small cohort of women and simulations that have subsequently been performed using the acquired data have shown that for three time points and a group size of up to 50, with alpha (Type I Error) and beta (Type II Error) set to 95% significance and 80% power, respectively, at least 35 patients would need to be recruited in order for the null hypothesis (that there is no significant reduction in total fibroid volume) to be potentially rejected.

WIDER IMPLICATIONS OF THE FINDINGS

The imaging protocol that we have developed represents a generic paradigm for measuring the volume of the uterus and uterine fibroids that can be readily incorporated in future studies of medical treatments of HMB. In the present study, SPRM-UPA failed to produce a significant reduction in the volume of the uterus or the total volume of fibroids (which were present in approximately half of the patients) after either two or three 12-week courses of treatment. This finding represents a new insight in respect of the management of HMB using treatment strategies that target hormone-dependence.

STUDY FUNDING/COMPETING INTERESTS

The UPA Versus Conventional Management of HMB (UCON) trial was funded by the EME Programme (Medical Research Council (MRC) and National Institutes of Health Research (NIHR)) (12/206/52). The views expressed in this publication are those of the authors and not necessarily those of the Medical Research Council, National Institute for Health Research, or Department of Health and Social Care.Medical Research Council (MRC) Centre grants to the Centre for Reproductive Health (CRH) (G1002033 and MR/N022556/1) are also gratefully acknowledged. H.C. has clinical research support for laboratory consumables and staff from Bayer AG and provides consultancy advice (All paid to Institution) for Bayer AG, PregLem SA, Gedeon Richter, Vifor Pharma UK Ltd, AbbVie Inc., and Myovant Sciences GmbH. H.C. has received royalties from UpToDate for an article on abnormal uterine bleeding. L.W. has received grant funding from Roche Diagnostics (Paid to Institution). All other authors have no conflicts to declare.

TRIAL REGISTRATION NUMBER

The study reported here is an embedded mechanism of action study (no comparator) within the UCON clinical trial (registration ISRCTN: 20426843).

Carotid flow as a surrogate of the left ventricular stroke volume

Transthoracic echocardiography (TTE) is a fundamental tool for hemodynamic monitoring in critical patients. It allows evaluating the left ventricle's stroke volume based on the measurement of the velocity-time integral (VTI) of the left ventricle outflow tract (LVOT). However, in the intensive care unit obtaining adequate echocardiographic views may present a challenge. We propose to measure, as a surrogate of the stroke volume, the carotid flow with a novel technique. This is an observational, prospective, and simple blind study, conducted in the intensive care unit of Sanatorio de los Arcos and Hospital Aleman, in Buenos Aires, Argentina. We measured the carotid systodiastolic flow (CSD) VTI and the carotid systolic flow (CS) VTI at the level of the left supraclavicular fossa and we compared it with the LVOT VTI obtained by TTE. We evaluated 43 subjects. Spearman's correlation coefficient between LVOT VTI and CS VTI was 0.81 (95% CI 0.67-0.89) and between LVOT VTI and CSD VTI was 0.89 (95% CI 0.81-0.94). The Bland-Altman method analysis of the 5-chamber apical window LVOT VTI compared to the CSD VTI showed a bias of - 0.2 (95% CI - 0.82 to 0.43), with a concordance interval between - 4.2 (95% CI - 5.2 to - 3.1) and 3.8 cm (95% CI 2.7 to 4.9). The percentage error was 37.9%. Almost 100% of the values fell within the concordance limits, and no trend was observed in bias across the spectrum of mean variables. Although the CSD VTI could not be interchangeable with the LVOT VTI, it could be considered as its surrogate.

Imagined Timed Up and Go test (iTUG) in people with Parkinson's Disease: test-retest reliability and validity

PURPOSE

To determine the test-retest reliability and validity of the Imagined Timed Up and Go Test (iTUG) as a Motor Imagery measure of temporal accuracy in people with Parkinson's Disease (PD).

MATERIALS AND METHODS

A descriptive study was conducted following the GRRAS recommendations. Thirty-two people with idiopathic, mild to moderate PD (Hoehn and Yahr I-III), without cognitive impairment (MMSE ≥ 24), were assessed twice (7-15 days apart) with the iTUG. The absolute unadjusted difference in seconds, and the absolute adjusted difference as percentage of estimation error, between real and imagined TUG times, were calculated as outcome measures. Test-retest reliability was assessed using a two-way mixed-effects model of the ICC. Construct validity was tested with the Imagined Box and Blocks Test (iBBT) and convergent validity with clinical characteristics of PD, using the Spearman's rank correlation coefficient.

RESULTS

The ICC for the unadjusted and adjusted measures of the iTUG was ICC = 0.61 and ICC = 0.55, respectively. Correlations between iTUG and iBBT were not statistically significant. The iTUG was partially correlated to clinical characteristics of PD.

CONCLUSIONS

Test-retest reliability of the iTUG was moderate. Construct validity between iTUG and iBBT was poor, so caution should be taken when using them concurrently to assess imagery's temporal accuracy.

Common carotid segmentation in 18 F-sodium fluoride PET/CT scans: Head-to-head comparison of artificial intelligence-based and manual method

BACKGROUND

Carotid atherosclerosis is a major cause of stroke, traditionally diagnosed late. Positron emission tomography/computed tomography (PET/CT) with ¹⁸ F-sodium fluoride (NaF) detects arterial wall micro-calcification long before macro-calcification becomes detectable by ultrasound, CT or magnetic resonance imaging. However, manual PET/CT processing is time-consuming and requires experience. We compared a convolutional neural network (CNN) approach with manual segmentation of the common carotids.

METHODS

Segmentation in NaF-PET/CT scans of 29 healthy volunteers and 20 angina pectoris patients were compared for segmented volume (Vol) and mean, maximal, and total standardized uptake values (SUVmean, SUVmax, and SUVtotal). SUVmean was the average of SUVmeans within the VOI, SUVmax the highest SUV in all voxels in the VOI, and SUVtotal the SUVmean multiplied by the Vol of the VOI. Intra and Interobserver variability with manual segmentation was examined in 25 randomly selected scans.

RESULTS

Bias for Vol, SUVmean, SUVmax, and SUVtotal were 1.33 ± 2.06, -0.01 ± 0.05, 0.09 ± 0.48, and 1.18 ± 1.99 in the left and 1.89 ± 1.5, -0.07 ± 0.12, 0.05 ± 0.47, and 1.61 ± 1.47, respectively, in the right common carotid artery. Manual segmentation lasted typically 20 min versus 1 min with the CNN-based approach. Mean Vol deviation at repeat manual segmentation was 14% and 27% in left and right common carotids.

CONCLUSIONS

CNN-based segmentation was much faster and provided SUVmean values virtually identical to manually obtained ones, suggesting CNN-based analysis as a promising substitute of slow and cumbersome manual processing.

Silicone Elastomeric-Based Materials of Soft Pneumatic Actuator for Lower-Limb Rehabilitation: Finite Element Modelling and Prototype Experimental Validation

This study describes the basic design, material selection, fabrication, and evaluation of soft pneumatic actuators (SPA) for lower-limb rehabilitation compression therapy. SPAs can be a promising technology in proactive pressure delivery, with a wide range of dosages for treating venous-related diseases. However, the most effective design and material selection of SPAs for dynamic pressure delivery have not been fully explored. Therefore, a SPA chamber with two elastomeric layers was developed for this study, with single-side inflation. The 3D deformation profiles of the SPA chamber using three different elastomeric rubbers were analyzed using the finite element method (FEM). The best SPA-compliant behavior was displayed by food-grade silicone A10 Shore with a maximum deformation value of 25.34 mm. Next, the SPA chamber was fabricated using A10 Shore silicone and experimentally validated. During the simulation in FEM, the air pressure was applied on the inner wall of the chamber (i.e., the affected area). This is to ensure the applied pressure was evenly distributed in the inner wall while the outer wall of the chamber remained undeformed for all compression levels. During the inflation process, pressure will be applied to the SPA chamber, causing exerted pressure on the skin which is then measured for comparison. The simulation and experimental results show an excellent agreement of pressure transmission on the skin for the pressure range of 0–120 mmHg, as depicted in the Bland–Altman plots. The findings exhibited promising results in the development of the SPA chamber using low-cost and biocompatible food-grade silicone.

Linear and Non-Linear Heart Rate Variability Indexes from Heart-Induced Mechanical Signals Recorded with a Skin-Interfaced IMU

Heart rate variability (HRV) indexes are becoming useful in various applications, from better diagnosis and prevention of diseases to predicting stress levels. Typically, HRV indexes are retrieved from the heart's electrical activity collected with an electrocardiographic signal (ECG). Heart-induced mechanical signals recorded from the body's surface can be utilized to record the mechanical activity of the heart and, in turn, extract HRV indexes from interbeat intervals (IBIs). Among others, accelerometers and gyroscopes can be used to register IBIs from precordial accelerations and chest wall angular velocities. However, unlike electrical signals, the morphology of mechanical ones is strongly affected by body posture. In this paper, we investigated the feasibility of estimating the most common linear and non-linear HRV indexes from accelerometer and gyroscope data collected with a wearable skin-interfaced Inertial Measurement Unit (IMU) positioned at the xiphoid level. Data were collected from 21 healthy volunteers assuming two common postures (i.e., seated and lying). Results show that using the gyroscope signal in the lying posture allows accurate results in estimating IBIs, thus allowing extracting of linear and non-linear HRV parameters that are not statistically significantly different from those extracted from reference ECG.

Hounsfield Units measured in low dose CT reliably assess vertebral trabecular bone density changes over two years in axial spondyloarthritis

OBJECTIVES

To describe low dose Computed Tomography (ldCT) Hounsfield Units (HU) two-year change-from-baseline values (expressing trabecular bone density changes) and analyse their inter-reader reliability per vertebra in radiographic axial spondyloarthritis (r-axSpA).

METHODS

We used 49 patients with r-axSpA from the multicentre two-year Sensitive Imaging in Ankylosing Spondylitis (SIAS) study. LdCT HU were independently measured by two trained readers at baseline and two years. Mean (standard deviation, SD) for the change-from-baseline HU values were provided per vertebra by reader. Intraclass correlation coefficients (ICC; absolute agreement, two-way random effect), Bland-Altman plots and smallest detectable change (SDC) were obtained. Percentages of vertebrae in which readers agreed on the direction of change and on change >|SDC| were computed.

RESULTS

Overall, 1,053 (98% of all possible) vertebrae were assessed by each reader both at baseline and two years. Over two years, HU mean change values varied from -23 to 28 and 29 for reader 1 and 2, respectively. Inter-reader reliability of the two-year change-from-baseline values per vertebra was excellent: ICC:0.91-0.99; SDC:6-10; Bland-Altman plots were homoscedastic, with negligible systematic error between readers. Readers agreed on the direction of change in 88-96% and on change >|SDC| in 58-94% of vertebrae, per vertebral level, from C3 to L5. Overall, similar results were obtained across all vertebrae.

CONCLUSION

LdCT measurement of HU is a reliable method to assess two-year changes in trabecular bone density at each vertebra from C3-L5. Being reliable across all vertebrae, this methodology can aid the study of trabecular bone density changes over time in r-axSpA, a disease affecting the whole spine.

An optimized method for estimating glutaminase activity in biological samples

Spectrophotometric methodologies have been used to assess glutaminase activity, for which coloured complexes have been developed that measure spectrophotometry across the visible spectrum using different reagents. The present paper describes a precise, simple and reliable procedure for quantifying glutaminase activity, which is a key enzyme in glutamine hydrolysis and also involved in glutamine metabolism regulation. The procedure presented here measures glutaminase activity by incubating glutaminase enzyme at 37 °C for 20 min with a glutamine substrate dissolved in a buffer (pH 8.6). The enzymatic reaction contains suitable activity of glutamate oxidase, which acts to convert glutamate to hydrogen peroxide and 2-oxoglutarate. To terminate the enzymatic activity, a working solution containing pyridine-2,6-dicarboxylic (PDA) acid and ammonium vanadate (AV) was added following incubation. Oxo-peroxo-pyridine-2,6-dicarboxylato-vanadate (OPDV), a stable orange-coloured chelate complex measuring 435 nm spectrophotometrically, was produced by the interaction between the generated hydrogen peroxide and the supplied reagent. Using the response surface methodology (RSM) as an indicator of the assay's accuracy, we employed the Box-Behnken design (BBD) to improve the method's design (the OPDV-Glutaminase assay). Improvement factors were the volume of working reagent solution (PDA/AV), volume of glutamate oxidase solution (GO), and incubation time. In matched samples, this novel method was verified against a Bland-Altman plot assessment of glutaminase activity using the indophenol methodology. A correlation value of 0.99 between the two methods' comparisons showed that the novel protocol was equally applicable to the reference method.

Body surface area equations for physically active men and women

OBJECTIVES

To improve predictive formulae for estimating body surface area (BSA) in healthy men and women using a modern three-dimensional scanner technology.

METHODS

Body surface areas were obtained from a convenience sample of 1267 US Marines (464 women and 803 men) using a whole body surface scanner (Size Stream SS20). The reliability of SS20 measures of total and regional BSA within participants was compared across triplicate scans. We then derived a series of formulae to estimate SS20-measured BSA using various combinations of sex, height, and mass. We also assessed relationships between percent body fat measured by dual-energy x-ray absorptiometry and sex-specific formulae errors in Marines.

RESULTS

Body surface areas recorded by the SS20 were highly reliable whether measured for the total body or by region (ICC ≥ .962). Formulae estimates of BSA from sex, height, and mass were precise (root-mean-square deviation, 0.031 m² ). Errors from the Marine Corps formulae were positively associated with percent body fat for men (p = .001) but not women (p = .843).

CONCLUSIONS

Clinicians, military leaders, and researchers can use the newly developed BSA formulae for precise estimates in healthy physically active men and women. Users should be aware that height- and mass-based BSA estimates are less accurate for individuals with extremely low or high percent body fat.

Reliability of bioreactance and pulse power analysis in measuring cardiac index during cytoreductive abdominal surgery with hyperthermic intraperitoneal chemotherapy (HIPEC)

PURPOSE

Various malignancies with peritoneal carcinomatosis are treated with cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (HIPEC). The hemodynamic instability resulting from fluid balance alterations during the procedure necessitates reliable hemodynamic monitoring. The aim of the study was to compare the accuracy, precision and trending ability of two less invasive hemodynamic monitors, bioreactance-based Starling SV and pulse power device LiDCOrapid with bolus thermodilution technique with pulmonary artery catheter in the setting of cytoreductive surgery with HIPEC.

METHODS

Thirty-one patients scheduled for cytoreductive surgery were recruited. Twenty-three of them proceeded to HIPEC and were included to the study. Altogether 439 and 430 intraoperative bolus thermodilution injections were compared to simultaneous cardiac index readings obtained with Starling SV and LiDCOrapid, respectively. Bland-Altman method, four-quadrant plots and error grids were used to assess the agreement of the devices.

RESULTS

Comparing Starling SV with bolus thermodilution, the bias was acceptable (0.13 l min^- 1 m^- 2, 95% CI 0.05 to 0.20), but the limits of agreement were wide (- 1.55 to 1.71 l min^- 1 m^- 2) and the percentage error was high (60.0%). Comparing LiDCOrapid with bolus thermodilution, the bias was acceptable (- 0.26 l min^- 1 m^- 2, 95% CI - 0.34 to - 0.18), but the limits of agreement were wide (- 1.99 to 1.39 l min^- 1 m^- 2) and the percentage error was high (57.1%). Trending ability was inadequate with both devices.

CONCLUSION

Starling SV and LiDCOrapid were not interchangeable with bolus thermodilution technique limiting their usefulness in the setting of cytoreductive surgery with HIPEC.

The accuracy of computerized biophotogrammetry in diagnosing changes in the cervical spine and its reliability for the cervical lordosis angle

BACKGROUND

Accuracy studies of biophotogrammetry protocols require standardization similar to radiography.

OBJECTIVE

To estimate the diagnostic accuracy of a biophotogrammetric assessment protocol for cervical hyperlordosis, compared to radiography, and its intra- and inter-examiner reliability for measuring the cervical lordosis angle.

METHODS

A study of diagnostic accuracy in women complaining of cervical pain. Two photos were taken using the CorelDraw biophotogrammetric protocol and one radiograph using the Cobb C1-C7 method. The Intra- and Inter-examiner reliability was calculated using the Kappa index and the intraclass correlation coefficient (ICC). The Bland-Altman plot and the ROC curve were presented.

RESULTS

The sample consisted of 19 women. The accuracy of biophotogrammetry was 94.73% and the reliability between biophotogrammetry and radiography presented an ICC of 0.84 and a Kappa of 0.87. The excellent intra (ICC = 0.94) and inter-examiner (ICC = 0.86) reliability of the biophotogrammetry was confirmed. The area under the ROC curve was 93.5%. The Bland-Altman plot indicated differences between the two instruments close to the mean (1.5∘).

CONCLUSION

The biophotogrammetric protocol proved to be accurate in diagnosing cervical hyperlordosis, with excellent reliability between the biophotogrammetric and radiographic assessments. It also demonstrated excellent intra- and inter-examiner reliability in measuring the cervical lordosis angle.

Inter-rater and intra-rater reliability of isotonic exercise monitoring device for measuring active knee extension

Background

The goal of this study was to assess the reliability of electromyography and range of motion measurements obtained using a knee exercise monitoring system. This device was developed to collect data on knee exercise activities.

Methods

Twenty healthy individuals performed isotonic quadriceps exercises in this study. The vastus medialis surface electromyography (sEMG) and range of motion (ROM) of the knee were recorded during the exercise using the isotonic knee exercise monitoring device, the Mobi6-6b, and a video camera system. Each subject underwent a second measuring session at least 24 h after the first session. To determine reliability, the intraclass correlation coefficients (ICCs) and standard error of measurement (SEM) at the 95% confidence interval were calculated, and a Bland-Altman analysis was performed.

Results

For inter-rater reliability, the ICCs of the mean absolute value (MAV) and root mean square (RMS) of sEMG were 0.73 (0.49, 0.86) and 0.79 (0.61, 0.89), respectively. ROM had an ICC of 0.93 (0.02, 0.98). The intra-rater reliability of the MAV of the sEMG was 0.89 (0.71, 0.96) and the intra-rater reliability of RMS of the sEMG was 0.88 (0.70, 0.95). The ROM between days had an intra-rater reliability of 0.82 (0.54, 0.93). The Bland-Altman analysis demonstrated no systematic bias in the MAV and RMS of sEMG, but revealed a small, systematic bias in ROM (-0.8311 degrees).

Conclusion

For sEMG and range of motion measures, the isotonic knee exercise monitoring equipment revealed moderate to excellent inter- and intra-rater agreement. However, the confidence interval of ROM inter-rater reliability was quite large, indicating a small agreement bias; hence, the isotonic knee exercise monitor may not be suitable for measuring ROM. This isotonic knee exercise monitor could detect and collect information on a patient's exercise activity for the benefit of healthcare providers.

Novice assessors demonstrate good intra-rater agreement and reliability when determining pressure pain thresholds; a cross-sectional study

Background

Experienced assessors show good intra-rater reproducibility (within-session and between-session agreement and reliability) when using an algometer to determine pressure pain thresholds (PPT). However, it is unknown whether novice assessors perform equally well. This study aimed to determine within and between-session agreement and reliability of PPT measurements performed by novice assessors and explored whether these parameters differed per assessor and algometer type.

Methods

Ten novice assessors measured PPTs over four test locations (tibialis anterior muscle, rectus femoris muscle, extensor carpi radialis brevis muscle and paraspinal muscles C5-C6) in 178 healthy participants, using either a Somedic Type II digital algometer (10 raters; 88 participants) or a Wagner Force Ten FDX 25 digital algometer (nine raters; 90 participants). Prior to the experiment, the novice assessors practiced PPTs for 3 h per algometer. Each assessor measured a different subsample of ~9 participants. For both the individual assessor and for all assessors combined (i.e., the group representing novice assessors), the standard error of measurement (SEM) and coefficient of variation (CV) were calculated to reflect within and between-session agreement. Reliability was assessed using intraclass correlation coefficients (ICC_1,1).

Results

Within-session agreement expressed as SEM ranged from 42 to 74 kPa, depending on the test location and device. Between-session agreement, expressed as SEM, ranged from 36 to 76 kPa and the CV ranged from 9-16% per body location. Individual assessors differed from the mean group results, ranging from -55 to +32 kPa or from -9.5 to +6.6 percentage points. Reliability was good to excellent (ICC_1,1: 0.87 to 0.95). Results were similar for both types of algometers.

Conclusions

Following 3 h of algometer practice, there were slight differences between assessors, but reproducibility in determining PPTs was overall good.

Test-Retest Reliability and Criterion Validity of the Spanish Version of Two Motor Imagery Questionnaires in People With Parkinson Disease

BACKGROUND AND PURPOSE

The Kinesthetic and Visual Imagery Questionnaire (KVIQ) and the Movement Imagery Questionnaire-Revised Second Version (MIQ-RS) are measurement instruments that assess motor imagery vividness. The aim of this study was to examine the validity and reliability of the Spanish KVIQ and MIQ-RS in people with Parkinson disease (PD).

METHODS

A longitudinal descriptive study was conducted following the COSMIN standards. Thirty-five people with idiopathic PD were evaluated twice (7-15 days apart) with the Spanish KVIQ and MIQ-RS. Structural validity, internal consistency, test-retest reliability (ICC), standard error of measurement (SEM), smallest detectable change (SDC), and criterion validity of the MIQ-RS and KVIQ long (KVIQ-20), short (KVIQ-10), and extended (KVIQ-34) versions and their subscales (if pertinent) were tested.

RESULTS

Factor analysis was satisfactory for the MIQ-RS, KVIQ-20, and KVIQ-10, providing evidence of their 2-dimensional structure. Evidence of the structural validity of the KVIQ-34 was not confirmed and thus was analyzed as an overall score. Revelle's ω > 0.9 showed excellent internal consistency. Test-retest reliability was moderate (ICC = 0.58-0.75) and higher for all visual subscales. SEM and SDC were up to 14.39% and 39.89% of the scores, respectively. Criterion validity between questionnaires and subscales was strong (Spearman's r > 0.7).

DISCUSSION AND CONCLUSIONS

The results provide evidence for the validity and reliability of the Spanish MIQ-RS, KVIQ-20, and KVIQ-10 to assess motor imagery vividness in people with PD, whereas the KVIQ-34 should only be interpreted as an overall score. Psychometric, procedural, and practical features of the questionnaires should be considered when applying into clinical practice.Video Abstract available for more insights from the authors (see the Video, Supplemental Digital Content 1, available at: http://links.lww.com/JNPT/A401).

Intra-individual comparison of liver stiffness measurements by magnetic resonance elastography and two-dimensional shear-wave elastography in 888 patients

PURPOSE

Quantitative elastography methods, such as ultrasound two-dimensional shear-wave elastography (2D-SWE) and magnetic resonance elastography (MRE), are used to diagnose liver fibrosis. The present study compared liver stiffness determined by 2D-SWE and MRE within individuals and analyzed the degree of agreement between the two techniques.

METHODS

In total, 888 patients who underwent 2D-SWE and MRE were analyzed. Bland-Altman analysis was performed after both types of measurements were log-transformed to a normal distribution and converted to a common set of units using linear regression analysis for differing scales. The expected limit of agreement (LoA) was defined as the square root of the sum of the squares of 2D-SWE and MRE precision. The percentage difference was expressed as (2D-SWEMRE)/ mean of the two methods×100.

RESULTS

A Bland-Altman plot showed that the bias and upper and lower LoAs (ULoA and LLoA) were 0.0002 (95% confidence interval [CI], -0.0057 to 0.0061), 0.1747 (95% CI, 0.1646 to 0.1847), and -0.1743 (95% CI, -0.1843 to -0.1642), respectively. In terms of percentage difference, the mean, ULoA, and LLoA were -0.5944%, 19.8950%, and -21.0838%, respectively. The calculated expected LoA was 17.1178% (95% CI, 16.6353% to 17.6002%), and 789 of 888 patients (88.9%) had a percentage difference within the expected LoA. The intraclass correlation coefficient of the two methods indicated an almost perfect correlation (0.8231; 95% CI, 0.8006 to 0.8432; P<0.001).

CONCLUSION

Bland-Altman analysis demonstrated that 2D-SWE and MRE were interchangeable within a clinically acceptable range.

Current Status of Measurement Accuracy for Total Hemoglobin Concentration in the Clinical Context

OBJECTIVE

The main objective of this investigation is to provide data about the accuracy of total hemoglobin concentration measurements with respect to clinical settings, and to devices within the categories of point-of-care and reference systems. In particular, tolerance of hemoglobin concentrations below 9 g/dL that have become common in clinical practice today determines the need to demonstrate the limits of measurement accuracy in patient care.

METHODS

Samples extracted from six units of heparinized human blood with total hemoglobin concentrations ranging from 3 to 18 g/dL were assigned to the test devices in a random order. The pool of test devices comprised blood gas analyzers, an automatic hematology analyzer, a laboratory reference method, and the point-of-care system HemoCue. To reduce the pre-analytic error, each sample was measured three times. Due to the characteristics of the tested devices and methods, we selected the mean values of the data from all these devices, measured at the corresponding total hemoglobin concentrations, as the reference.

MAIN RESULTS

The measurement results of the test devices overlap within strict limits (R² = 0.999). Only the detailed analysis provides information about minor but systematic deviations. In the group of clinically relevant devices, which are involved in patient blood management decisions, the relative differences were within the limit of +/- 5 % for values down to 3 g/dL.

CONCLUSIONS

A clinically relevant change of +/- 0.5 g/dL of total hemoglobin concentration can be detected with all selected devices and methods. Compliance with more stringent definitions-these are the relative differences of 5 % in relation to the corresponding reference values and the clinically adapted thresholds in the format of a tolerance level analysis-was achieved by the clinical devices assessed here.

Agreement between low-dose and ultra-low-dose chest CT for the diagnosis of viral pneumonia imaging patterns during the COVID-19 pandemic

Background

Chest CT scan has an important role in the diagnosis and management of COVID-19 infection. A major concern in radiologic assessment of the patients is the radiation dose. Research has been done to evaluate low-dose chest CT in the diagnosis of pulmonary lesions with promising findings. We decided to determine diagnostic performance of ultra-low-dose chest CT in comparison to low-dose CT for viral pneumonia during the COVID-19 pandemic.

Results

167 patients underwent both low-dose and ultra-low-dose chest CT scans. Two radiologists blinded to the diagnosis independently examined ultra-low-dose chest CT scans for findings consistent with COVID-19 pneumonia. In case of any disagreement, a third senior radiologist made the final diagnosis. Agreement between two CT protocols regarding ground-glass opacity, consolidation, reticulation, and nodular infiltration were recorded. On low-dose chest CT, 44 patients had findings consistent with COVID-19 infection. Ultra-low-dose chest CT had sensitivity and specificity values of 100% and 98.4%, respectively for diagnosis of viral pneumonia. Two patients were falsely categorized to have pneumonia on ultra-low-dose CT scan. Positive predictive value and negative predictive value of ultra-low-dose CT scan were respectively 95.7% and 100%. There was good agreement between low-dose and ultra-low-dose methods (kappa = 0.97; P < 0.001). Perfect agreement between low-dose and ultra-low-dose scans was found regarding diagnosis of ground-glass opacity (kappa = 0.83, P < 0.001), consolidation (kappa = 0.88, P < 0.001), reticulation (kappa = 0.82, P < 0.001), and nodular infiltration (kappa = 0.87, P < 0.001).

Conclusion

Ultra-low-dose chest CT scan is comparable to low-dose chest CT for detection of lung infiltration during the COVID-19 outbreak while maintaining less radiation dose. It can also be used instead of low-dose chest CT scan for patient triage in circumstances where rapid-abundant PCR tests are not available.

Determining reference ranges and sample sizes in parallel-group studies

BACKGROUND AND OBJECTIVES

Reference ranges are widely used to locate the major range of the target probability distribution. When future measurements fall outside the reference range, they are classified as atypical and require further investigation. The fundamental principles and statistical properties of reference ranges are closely related to those of tolerance interval procedures. Existing investigations of reference ranges and tolerance intervals mainly devoted to the primitive cases of one- and paired-sample designs. Although reference ranges hold considerable promise for parallel group designs, the corresponding methodological and computational issues for determining reference limits and sample sizes have not been adequately addressed.

METHODS

This paper describes a complete collection of one- and two-sided reference ranges for assessing measurement differences in parallel-group studies that assume variance homogeneity.

RESULTS

The problem of sample size determination for precise reference ranges is also examined under the expected half-width and assurance probability considerations. Unlike the current methods, the suggested sample size criteria explicitly accommodate desired interval width in precise interval estimation.

CONCLUSIONS

Theoretical examinations and empirical assessments are presented to validate the usefulness of the proposed reference range and sample size procedures. To enhance the usages of the recommended techniques in practical applications, computer programs are developed for efficient calculation and exact analysis. A real data example regarding tablet absorption rate and extent is presented to illustrate the suggested assessments between two drug formulations.

Assessing Agreement When Agreement Is Hard to Assess-The Agatston Score for Coronary Calcification

Method comparison studies comprised simple scatterplots of paired measurements, a 45-degree line as benchmark, and correlation coefficients up to the advent of Bland-Altman analysis in the 1980s. The Agatston score for coronary calcification is based on computed tomography of the heart, and it originated in 1990. A peculiarity of the Agatston score is the often-observed skewed distribution in screening populations. As the Agatston score has manifested itself in preventive cardiology, it is of interest to investigate how reproducibility of the Agatston score has been established. This review is based on literature findings indexed in MEDLINE/PubMed before 20 November 2021. Out of 503 identified articles, 49 papers were included in this review. Sample sizes were highly variable (10-9761), the main focus comprised intra- and interrater as well as intra- and interscanner variability assessments. Simple analysis tools such as scatterplots and correlation coefficients were successively supplemented by first difference, later Bland-Altman plots; however, only very few publications were capable of deriving Limits of Agreement that fit the observed data visually in a convincing way. Moreover, several attempts have been made in the recent past to improve the analysis and reporting of method comparison studies. These warrant increased attention in the future.

Digital versus radiographic accuracy evaluation of guided implant surgery: an in vitro study

Background

Cone-beam computed tomography (CBCT) is the most widely used method for postsurgical evaluation of the accuracy of guided implant surgery. However, the disadvantages of CBCT include radiation exposure, artifacts caused by metal implants, and high cost. Few studies have introduced a digital registration method to replace CBCT for evaluating the accuracy of guided surgery. The purpose of this study was to compare digital registration to conventional CBCT in terms of the capacity to evaluate the implant positioning accuracy of guided surgery.

Materials and methods

This in vitro study included 40 acrylic resin models with posterior single mandibular tooth loss. Guided surgery software was used to determine the optimal implant position; 40 tooth-supported fully guided drilling templates were designed and milled accordingly. After the guided surgery, the accuracies of the surgical templates were evaluated by conventional CBCT and digital registration. For evaluation by conventional CBCT, postsurgical CBCT scans of the resin models were performed. The CBCT data were reconstructed and superimposed on the implant planning data. For digital registration, we constructed a virtual registration unit that consisted of an implant replica and a scan body. Next, we obtained postsurgical optical scans of resin models with the scan body. The postsurgical implant position was identified by superimposition of the registration unit and optical scan data. The implant planning data and postsurgical implant position data were superimposed; deviations were reported in terms of distance for implant entry/apex point and in terms of angle for the implant axis. Interclass correlation coefficients (ICCs) and Bland–Altman plots were used to analyze the agreement between the two evaluation methods.

Results

The ICCs between the two methods were 0.986, 0.993, and 0.968 for the entry point, apex point, and angle, respectively; all were significantly greater than 0.75 (p < 0.001). Bland–Altman plots showed that the 95% limits of agreement of the differences were − 0.144 to + 0.081 mm, − 0.135 to + 0.147 mm, and − 0.451° to + 0.729° for the entry point, apex point, and angle, respectively; all values were within the maximum tolerated difference.

Conclusion

Conventional CBCT and digital registration showed good agreement in terms of evaluating the accuracy of implant positioning using tooth-supported surgical templates.

Characterizing Standardized Functional Data at Inpatient Rehabilitation Facilities

OBJECTIVE

The Improving Medicare Post-Acute Care Transformation Act of 2014 mandates using standardized patient functional data across post-acute settings. This study characterized similarities and differences in clinician-observed scores of self-care and transfer items for the standardized section GG functional domain and the functional independent measure (FIM) at inpatient rehabilitation facilities.

DESIGN

We conducted secondary analyses of 2017 Uniform Data System for Medical Rehabilitation national data. Patients were assessed by clinicians on both section GG and FIM at admission and discharge. We identified 7 self-care items and 6 transfer items in section GG conceptually equivalent with FIM. Clinician-assessed scores for each pair of items were examined using score distributions, Bland-Altman plot, correlation (Pearson coefficients), and agreement (kappa and weighted kappa) analyses.

SETTING AND PARTICIPANTS

In all, 408,491 patients were admitted to Uniform Data System for Medical Rehabilitation-affiliated inpatient rehabilitation facilities with one of the following impairments: stroke, brain dysfunction, neurologic condition, orthopedic disorders, and debility.

MEASURES

Section GG and FIM.

RESULTS

Patients were scored as more functionally independent in section GG compared with FIM, but change score distributions and score orders within impairment groups were similar. Total scores in section GG had strong positive correlations (self-care: r = 0.87 and 0.95; transfer: r = 0.82 and 0.90 at admission and discharge, respectively) with total FIM scores. Weak to moderate ranking agreements with total FIM scores were observed (self-care: kappa = 0.49 and 0.60; transfers: kappa = 0.43 and 0.52 at admission and discharge, respectively). Lower agreements were observed for less able patients at admission and for higher ability patients of their change scores.

CONCLUSIONS AND IMPLICATIONS

Overall, response patterns were similar in section GG and FIM across impairments. However, variations exist in score distributions and ranking agreement. Future research should examine the use of GG codes to maintain effective care, outcomes, and unbiased reimbursement across post-acute settings.

"Global" cardiac atherosclerotic burden assessed by artificial intelligence-based versus manual segmentation in 18F-sodium fluoride PET/CT scans: Head-to-head comparison

BACKGROUND

Artificial intelligence (AI) is known to provide effective means to accelerate and facilitate clinical and research processes. So in this study it was aimed to compare a AI-based method for cardiac segmentation in positron emission tomography/computed tomography (PET/CT) scans with manual segmentation to assess global cardiac atherosclerosis burden.

METHODS

A trained convolutional neural network (CNN) was used for cardiac segmentation in 18F-sodium fluoride PET/CT scans of 29 healthy volunteers and 20 angina pectoris patients and compared with manual segmentation. Parameters for segmented volume (Vol) and mean, maximal, and total standardized uptake values (SUVmean, SUVmax, SUVtotal) were analyzed by Bland-Altman Limits of Agreement. Repeatability with AI-based assessment of the same scans is 100%. Repeatability (same conditions, same operator) and reproducibility (same conditions, two different operators) of manual segmentation was examined by re-segmentation in 25 randomly selected scans.

RESULTS

Mean (± SD) values with manual vs. CNN-based segmentation were Vol 617.65 ± 154.99 mL vs 625.26 ± 153.55 mL (P = .21), SUVmean 0.69 ± 0.15 vs 0.69 ± 0.15 (P = .26), SUVmax 2.68 ± 0.86 vs 2.77 ± 1.05 (P = .34), and SUVtotal 425.51 ± 138.93 vs 427.91 ± 132.68 (P = .62). Limits of agreement were - 89.42 to 74.2, - 0.02 to 0.02, - 1.52 to 1.32, and - 68.02 to 63.21, respectively. Manual segmentation lasted typically 30 minutes vs about one minute with the CNN-based approach. The maximal deviation at manual re-segmentation was for the four parameters 0% to 0.5% with the same and 0% to 1% with different operators.

CONCLUSION

The CNN-based method was faster and provided values for Vol, SUVmean, SUVmax, and SUVtotal comparable to the manually obtained ones. This AI-based segmentation approach appears to offer a more reproducible and much faster substitute for slow and cumbersome manual segmentation of the heart.

Bland-Altman Plot: Agreement Between Ultrasound-measured Placenta Thickness and Other Biometric Parameters in the Determination of Gestational Age

Purpose

The aim of this article is to evaluate the agreement of placenta thickness (PT) with other foetal biometric parameters in the determination of gestational age (GA) in normal singleton foetuses.

Materials and Methods

The study was a cross-sectional descriptive study conducted among 406 consecutively recruited pregnant women with singleton foetuses at 15-40 weeks of gestation at the National Hospital, Abuja, Nigeria from October to December 2019. Biparietal diameter (BPD), femur length (FL), head circumference (HC), abdominal circumference (AC), and PT were measured using standard measurement protocols. Bland and Altman (BA) plots were used to compare PT and other foetal biometric parameters. The significant statistical level was determined at a critical value of P < 0.05.

Results

The mean age of study participants was 31.8 ± 4.8 years. The BA plot of PT and HC demonstrated a normal distribution; the mean difference was around zero (3.968) and 95% of the measurements fell within 2SD of the mean. The BA plot of HC and AC measurements also showed that the 95% limits of agreement for differences fell within 10% of the mean of the measurements (-4.236 to 15.987 with a mean difference of 5.876), indicating good agreement between the two pairs of variables. However, BA plots between PT and BPD as well as PT and FL showed no agreement.

Conclusion

This study indicates that there is good agreement or comparability between PT and HC measurements as well as between PT and AC measurements. Hence, either HC or AC measurements may be interchangeable with PT measurements in the ultrasound determination of GA. However, PT measurements did not agree well with BPD and FL measurements, respectively.

Optimized Solid-Phase Mesh-Enhanced Sorption from Headspace (SPMESH) for Rapid Sub-ng/kg Measurements of 3-Isobutyl-2-methoxypyrazine (IBMP) in Grapes

Parallel extraction of headspace volatiles from multiwell plates using sorbent sheets (HS-SPMESH) followed by direct analysis in real-time high-resolution mass spectrometry (DART-HRMS) can be used as a rapid alternative to solid-phase micro-extraction (SPME) gas-chromatography mass-spectrometry (GC-MS) for trace level volatile analyses. However, an earlier validation study of SPMESH-DART-MS using 3-isobutyl-2-methoxypyrazine (IBMP) in grape juice showed poor correlation between SPMESH-DART-MS and a gold standard SPME-GC-MS around the compound’s odor detection threshold (<10 ng/kg) in grape juice, and lacked sufficient sensitivity to detect IBMP at this concentration in grape homogenate. In this work, we report on the development and validation of an improved SPMESH extraction approach that lowers the limit of detection (LOD < 0.5 ng/kg), and regulates crosstalk between wells (<0.5%) over a calibration range of 0.5−100 ng/kg. The optimized SPMESH-DART-MS method was validated using Cabernet Sauvignon and Merlot grape samples harvested from commercial vineyards in the central valley of California (n = 302) and achieved good correlation and agreement with SPME-GC-MS (R2 = 0.84) over the native range of IBMP (<0.5−20 ng/kg). Coupling of SPMESH to a lower resolution triple quadrupole (QqQ)-MS via a new JumpShot-HTS DART source also achieved low ng/kg detection limits, and throughput was improved through positioning stage optimizations which reduced time spent on intra-well SPMESH areas.

Clinical Accuracy of Non-Contact Forehead Infrared Thermometer Measurement in Children: An Observational Study

We evaluated the clinical reliability and utility of temperature measurements using no-contact forehead infrared thermometers (NCFITs) by comparing their temperature measurements with those obtained using infrared tympanic thermometers (IRTTs) in children. In this observational, prospective, and cross-sectional study, we enrolled 255 children (aged 1 month to 18 years) from the pediatric surgery ward at a tertiary medical center in Korea. The mean age of the children was 9.05 ± 5.39 years, and 54.9% were boys. The incidence rate of fever, defined as an IRTT reading of ≥38.0 °C, was 15.7%. The ICC coefficient for the assessment of agreement between temperatures recorded by the NCFIT and IRTT was 0.87, and the κ-coefficient was 0.83. The bias and 95% limits of agreement were 0.15 °C (−0.43 to 0.73). For an accurate diagnosis of fever (≥38 °C), the false-negative rate was much lower, but the false-positive rate was higher, especially in 6-year-old children. Therefore, NCFITs can be used to screen children for fever. However, a secondary check is required using another thermometer when the child’s temperature is >38 °C. NCFITs are proposed for screening but not for measuring the temperature. For the latter, an accurate and reliable thermometer shall be used.

Agreement and Precision of Deuterium Dilution for Total Body Water and Multicompartment Body Composition Assessment in Collegiate Athletes

BACKGROUND

Deuterium oxide (D2O) dilution is the criterion method for total body water (TBW) measurement, but results may vary depending on the specimen type, analysis method, and analyzing laboratory. Bioelectrical impedance (BIA) estimates TBW, but results may vary by device make and model.

OBJECTIVES

We investigated the accuracy and precision of TBW estimates and how measurement conditions affected the accuracy of body composition using multicompartment body composition models.

METHODS

Eighty collegiate athletes received duplicate TBW measures acquired from 3 BIA devices (S10, SFB7, and SOZO) and from unique D2O combinations of specimen type (saliva, urine), analysis methodology [Fourier transform infrared spectrophotometry (FTIR), isotope-ratio mass spectrometry (IRMS)], and 3 different laboratories. TBW measures were substituted into 2-compartment (2C) and 5-compartment (5C) body composition models. Criterion measures were compared using Lin's concordance correlation coefficient cutoff of poor (<0.90), moderate (0.90-0.95), substantial (0.95-0.99), and almost perfect (>0.99).

RESULTS

Fifty-one participants (26 female) completed the protocol. Using IRMS saliva as the criterion TBW, all other measures produced a substantial or almost perfect agreement, except for SFB7 (poor) and SOZO (moderate). The 2C body composition measures using D2O and BIA produced poor agreement except for moderate agreement for lab 3 FTIR saliva. The 5C body composition measures using D2O produced a substantial agreement, whereas the BIA device S10 and SOZO had a moderate agreement, while the SFB7 had a poor agreement to the criterion. Test-retest precision varied between techniques from 0.3% to 1.2% for TBW.

CONCLUSIONS

Small differences in TBW measurement led to significant differences in 2C models. The 5C models partially mitigate differences seen in 2C models when different TBW measures are used. Interchanging TBW measures in multicompartment models can be problematic and should be performed with these considerations.

Intra-individual Comparisons of the Ultrasound-Guided Attenuation Parameter and the Magnetic Resonance Imaging-Based Proton Density Fat Fraction Using Bias and Precision Statistics

Ultrasound-based techniques using the attenuation coefficient, including the ultrasound-guided attenuation parameter (UGAP), have been developed for the quantification of hepatic steatosis. The magnetic resonance imaging-based proton density fat fraction (MRI-PDFF) is considered to be more accurate than liver biopsy for liver fat quantification. The aim of this study was to perform intra-individual comparisons of UGAP and MRI-PDFF for determining hepatic steatosis grade. The study enrolled 309 patients who underwent UGAP and MRI-PDFF measurements. Bland-Altman analysis was conducted after transforming MRI-PDFF values to a normal distribution and converted to a common set of units using linear regression analysis for differing scales. The expected limits of agreement (LOA) was defined as the square root of the sum of the squares of UGAP and MRI-PDFF precision. A Bland-Altman plot revealed that the bias and upper and lower LOAs (ULOA and LLOA) were -0.0047, 0.1160 and -0.1255, respectively. The percentage difference indicated that the mean, ULOA and LLOA were -1.1434%, 18.1723% and -20.4590%, respectively. The calculated expected LOA was 18.5449%, and 283 of 309 patients (91.6%) had a percentage difference within 18.5449%. Bland-Altman analysis revealed that UGAP and MRI-PDFF were interchangeable within a clinically acceptable range.

Aortic wall segmentation in 18F-sodium fluoride PET/CT scans: Head-to-head comparison of artificial intelligence-based versus manual segmentation

BACKGROUND

We aimed to establish and test an automated AI-based method for rapid segmentation of the aortic wall in positron emission tomography/computed tomography (PET/CT) scans.

METHODS

For segmentation of the wall in three sections: the arch, thoracic, and abdominal aorta, we developed a tool based on a convolutional neural network (CNN), available on the Research Consortium for Medical Image Analysis (RECOMIA) platform, capable of segmenting 100 different labels in CT images. It was tested on 18F-sodium fluoride PET/CT scans of 49 subjects (29 healthy controls and 20 angina pectoris patients) and compared to data obtained by manual segmentation. The following derived parameters were compared using Bland-Altman Limits of Agreement: segmented volume, and maximal, mean, and total standardized uptake values (SUVmax, SUVmean, SUVtotal). The repeatability of the manual method was examined in 25 randomly selected scans.

RESULTS

CNN-derived values for volume, SUVmax, and SUVtotal were all slightly, i.e., 13-17%, lower than the corresponding manually obtained ones, whereas SUVmean values for the three aortic sections were virtually identical for the two methods. Manual segmentation lasted typically 1-2 hours per scan compared to about one minute with the CNN-based approach. The maximal deviation at repeat manual segmentation was 6%.

CONCLUSIONS

The automated CNN-based approach was much faster and provided parameters that were about 15% lower than the manually obtained values, except for SUVmean values, which were comparable. AI-based segmentation of the aorta already now appears as a trustworthy and fast alternative to slow and cumbersome manual segmentation.

Utility and validity of the Brief Psychiatric Rating Scale (BPRS) as a transdiagnostic scale

The Brief Psychiatric Rating Scale (BPRS) was originally conceived to assess psychopathology in several psychiatric disorders, making it an appropriate candidate to be used as a transdiagnostic instrument. We analyzed the utility and validity of the BPRS in a diagnostically heterogeneous sample of 600 psychiatric inpatients. As a comparator, we chose the mini-ICF-APP, a scale used to measure functioning and impairment across the diagnostic spectrum. Both scales had good internal consistency. The BPRS and the mini-ICF-APP showed a moderate correlation, with good levels of agreement. We were able to identify general symptoms present across the diagnostic spectrum, influencing severity and a cluster of symptoms specific for each diagnosis. Our results show the utility and validity of the BPRS as a transdiagnostic assessment tool that could easily be introduced in routine clinical work.

Assessing the Utility of a Quality-of-Care Assessment Tool Used in Assessing Comprehensive Care Services Provided by Community Health Workers in South Africa

Background

Few studies exist on the tools for assessing quality-of-care of community health worker (CHW) who provide comprehensive care, and for available tools, evidence on the utility is scanty. We aimed to assess the utility components of a previously-reported quality-of-care assessment tool developed for summative assessment in South Africa.

Methods

In two provinces, we used ratings by 21 CHWs and three team leaders in two primary health care facilities per province regarding whether the tool covered everything that happens during their household visits and whether they were happy to be assessed using the tool (acceptability and face validity), to derive agreement index (≥85%, otherwise the tool had to be revised). A panel of six experts quantitatively validated 11 items of the tool (content validity). Content validity index (CVI), of individual items (I-CVI) or entire scale (S-CVI), should be >80% (excellent). For the inter-rater reliability (IRR), we determined agreement between paired observers' assigned quality-of-care messages and communication scores during 18 CHW household visits (nine households per site). Bland and Altman plots and multilevel model analysis, for clustered data, were used to assess IRR.

Results

In all four CHW and team leader sites, agreement index was ≥85%, except for whether they were happy to be assessed using the tool, where it was <85% in one facility. The I-CVI of the 11 items in the tool ranged between 0.83 and 1.00. For the S-CVI, all six experts agreed on relevancy (universal agreement) in eight of 11 items (0.72) whereas the average of I-CVIs, was 0.95. The Bland-Altman plot limit of agreements between paired observes were −0.18 to 0.44 and −0.30 to 0.44 (messages score); and −0.22 to 0.45 and −0.28 to 0.40 (communication score). Multilevel modeling revealed an estimated reliability of 0.77 (messages score) and 0.14 (communication score).

Conclusion

The quality-of-care assessment tool has a high face and content validity. IRR was substantial for quality-of-care messages but not for communication score. This suggests that the tool may only be useful in the formative assessment of CHWs. Such assessment can provide the basis for reflection and discussion on CHW performance and lead to change.