Purpose
The Cobb technique is the universally accepted method for measuring the severity of spinal deformities. Traditionally, Cobb angles have been measured using protractor and pencil on hardcopy ...radiographic films. The new generation of mobile ‘smartphones’ make accurate angle measurement possible using an integrated accelerometer, providing a potentially useful clinical tool for assessing Cobb angles. The purpose of this study was to compare Cobb angle measurements performed using a smartphone and traditional protractor in a series of 20 adolescent idiopathic scoliosis patients.
Methods
Seven observers measured major Cobb angles on 20 pre-operative postero-anterior radiographs of Adolescent Idiopathic Scoliosis patients with both a standard protractor and using an Apple iPhone. Five of the observers repeated the measurements at least a week after the original measurements.
Results
The mean absolute difference between pairs of smartphone/protractor measurements was 2.1°, with a small (1°) bias toward lower Cobb angles with the iPhone. 95% confidence intervals for intra-observer variability were ±3.3° for the protractor and ±3.9° for the iPhone. 95% confidence intervals for inter-observer variability were ±8.3° for the iPhone and ±7.1° for the protractor. Both of these confidence intervals were within the range of previously published Cobb measurement studies.
Conclusions
We conclude that the iPhone is an equivalent Cobb measurement tool to the manual protractor, and measurement times are about 15% less. The widespread availability of inclinometer-equipped mobile phones and the ability to store measurements in later versions of the angle measurement software may make these new technologies attractive for clinical measurement applications.
Background:
Skin autofluorescence has been used to assess longer term glycemic control and risk of complications. There is however no agreed site at which autofluorescence should be measured. This ...study evaluated the within- and between-site agreement in measurement of skin autofluorescence using a noninvasive advanced glycation end product (AGE) reader.
Methods:
Overall, 132 participants were included: 16 with diabetes-related foot ulcers (DFU), 63 with diabetes but without foot ulcers (DMC), 53 without diabetes or foot ulcers (HC). Skin autofluorescence was measured using the AGE Reader (DiagnOptics technologies BV, the Netherlands). Three consecutive skin autofluorescence measurements were each performed at six different body sites: the volar surfaces of both forearms (arms), dorsal surfaces of both calves (legs), and plantar surfaces of both feet (feet). Within- and between-site agreements were analyzed with concordance correlation coefficients (CCC) and 95% confidence intervals (95% CI), absolute mean differences (±standard deviation), and Bland-Altman limits of agreement.
Results:
The agreement between repeat assessments at the same site was almost perfect (CCC 95% CI ranging from 0.94 0.91-0.96 for assessments in the right foot to 0.99 0.99-0.99 for assessments in the left arm). The limits of agreement were narrow within ±0.5 arbitrary units for all sites. The between-site agreement in measurements was poor (CCC < 0.65) with large maximum absolute mean differences (±SD) in arbitrary units (DFU = 3.40 ±2.04; DMC = 3.15 ±2.45; HC = 2.72 ±1.83) and wide limits of agreement.
Conclusions:
Skin autofluorescence measurements can be repeated at the same site with adequate repeatability but measurements at different sites in the same patient have marked differences. The reason for this variation across sites and whether this has any role in diabetes-related complications needs further investigation.
BACKGROUND:The rib-vertebral angle (RVAD) differentiates between progressive and resolving infantile idiopathic scoliosis (IIS) curves. Those with a RVAD<20 degrees often resolve without treatment, ...whereas those >20 degrees often progress and require treatment. The mathematical magnitude of RVAD measurement variability has not been described, and was thus the purpose of this study. It is important to know the reliability of RVAD measurements so as to understand changes that can be attributed to observer error alone.
PURPOSE:The purpose of the study was to mathematically determine the intraobserver and interobserver measurement variability of the RVAD difference in IIS.
METHODS:A convenience sample of 50 patients with IIS was selected. The RVAD was measured twice by 7 different observers separated by a minimum of 3 weeks. The 7 different readers chosen to measure the RVAD were 2 orthopaedic residents, 1 pediatric radiologist, and 4 attending pediatric orthopaedic surgeons. The same goniometer was used for all measurements. Intraobserver and interobserver measurement variability was determined using 3 well known used statistical methods.
RESULTS:The 3 different methods used to determine intraobserver and interobserver variability using 95% prediction/confidence limits gave very similar results. Intraobserver variability was ∼24 degrees and the interobserver variability was ∼23 degrees.
DISCUSSION:The utility of the RVAD in medical decision-making and counseling of patients with IIS should be approached with caution when used in isolation due to the large measurement variability.
LEVEL OF EVIDENCE:Level 3.
On a daily basis, individuals between 12 and 25 years of age engage with their mobile devices for many hours. Social Media Use (SMU) has important implications for the social life of younger ...individuals in particular. However, measuring SMU and its effects often poses challenges to researchers. In this exploratory study, we focus on some of these challenges, by addressing how plurality in the measurement and age-specific characteristics of SMU can influence its relationship with measures of subjective mental health (MH). We conducted a survey among a nationally representative sample of Dutch adolescents and young adults (N = 3,669). Using these data, we show that measures of SMU show little similarity with each other, and that age-group differences underlie SMU. Similar to the small associations previously shown in social media-effects research, we also find some evidence that greater SMU associates to drops and to increases in MH. Albeit nuanced, associations between SMU and MH were found to be characterized by both linear and quadratic functions. These findings bear implications for the level of association between different measures of SMU and its theorized relationship with other dependent variables of interest in media-effects research.
Objective: To assess the intra-individual variation in carotid artery longitudinal wall motion (CALM) in healthy adults in order to determine the amount of data required to generate a representative ...measurement of CALM. Approach: We conducted an analysis of 27 healthy men to determine whether calculation of resting individual CALM outcomes is dependent on the number of averaged heart cycles. CALM was assessed at rest, 1-2 cm proximal to the right carotid bifurcation during a breath hold and was segmented into three motion displacements: systolic anterograde CALM, systolic retrograde CALM, and diastolic CALM. A 2D measure of total carotid artery motion (RALength) was also determined from the longitudinal and radial displacements. Outcomes were averaged discretely using two, three, four, five, and six consecutive heart cycles to assess the impact of additional data on intra-individual coefficients of variation (CV%) and intra-class correlations (ICC). Main results: Calculated means were similar between all heart cycle averaging for CALM displacements (all P > 0.05), though the two-heart cycle average of RALength (P = 0.06) was reduced in comparison to all other averages. Averaging data from four heart cycles was sufficient to generate a plateau in the variability in resting CALM displacements, such that within-subject ICC values all reached >0.90 and CV% were similar to previously reported day-to-day variability in healthy adults. Significance: There is variability in beat-to-beat measures of CALM that should be considered when designing protocols for data collection and analysis. We suggest that four consecutive heart cycles should be averaged to generate representative resting CALM outcomes in humans. While indices of variability were reduced when assessing outcomes generated from two to four heart cycles, no further improvements were observed when more heart cycles were included, indicating that averaging more than four heart cycles is likely not required.
Machine-learning (ML)-based automated measurement of echocardiography images emerges as an option to reduce observer variability. The objective of the study is to improve the accuracy of a ...pre-existing automated reading tool ('original detector') by federated ML-based re-training.
was based on the echocardiography images of
= 4965 participants of the population-based Characteristics and Course of Heart Failure Stages A-B and Determinants of Progression Cohort Study. We implemented federated ML: echocardiography images were read by the Academic Core Lab Ultrasound-based Cardiovascular Imaging at the University Hospital Würzburg (UKW). A random algorithm selected 3226 participants for re-training of the original detector. According to data protection rules, the generation of ground truth and ML training cycles took place within the UKW network. Only non-personal training weights were exchanged with the external cooperation partner for the refinement of ML algorithms. Both the original detectors as the re-trained detector were then applied to the echocardiograms of
= 563 participants not used for training. With regard to the human referent, the re-trained detector revealed (i) superior accuracy when contrasted with the original detector's performance as it arrived at significantly smaller mean differences in all but one parameter, and a (ii) smaller absolute difference between measurements when compared with a group of different human observers.
Population data-based ML in a federated ML set-up was feasible. The re-trained detector exhibited a much lower measurement variability than human readers. This gain in accuracy and precision strengthens the confidence in automated echocardiographic readings, which carries large potential for applications in various settings.
Background:
Advancements in the Digitial Image Correlation (DIC) technique over the past decade have greatly improved spatial resolution. However, many processes, such as plastic deformation, have a ...temporal component spanning from fractions of a second to minutes that has not yet been addressed in detail, particularly for DIC conducted in-situ in the scanning electron microscope (SEM).
Objective:
To develop a methodology for conducting time-resolved digital image correlation in the SEM for analysis of time-dependent mechanical deformation phenomena. Methods: Microscope and electron beam scanning parameters that influence the rate at which time-resolved DIC information is mapped are experimentally investigated, providing a guide for use over a range of timescales and resolutions.
Results:
Time-resolved DIC imaging is demonstrated on a Ti-7Al alloy, where slip band propagation is resolved with imaging dwell times of seconds. The limits of strain resolution and strain collection speeds are analyzed.
Conclusions:
The new developed methodology can be applied to a wide range of materials loaded in-situ to quantify time-dependent plastic deformation phenomena.
PURPOSE:To ensure optimal care of patients, cornea specialists measure corneal features, including epithelial defects (ED), with slit-lamp calipers. However, caliper measurements are subject to ...interphysician variability. We examined the extent of variability in ED measurements between cornea specialists and discuss the potential clinical impact.
METHODS:A total of 48 variably sized EDs were created in pig eyes. Three cornea specialists measured the maximum vertical and horizontal ED lengths to the nearest 10th of a millimeter using slit-lamp microscopy. An absolute difference in ED measurement between cornea specialists of 0.5 mm was chosen to be the a priori threshold for clinical significance and was evaluated by the Wilcoxon signed-rank test. Interrater reliability was assessed by intraclass correlation coefficients.
RESULTS:The average absolute difference in the vertical ED length between pairs of examiners ranged from 0.54 to 0.63 mm, and that of the horizontal ED length ranged from 0.44 to 0.46 mm. These differences in ED measurement were not significantly different from 0.5 mm (all P > 0.06). However, pairs of examiners differed in vertical ED length measurements by >0.5 mm in 44% to 52% of EDs and by >1.0 mm in 13% to 17% of EDs. Pairs of examiners differed in horizontal ED length measurements by >0.5 mm in 31% to 40% of EDs and by >1.0 mm in 10% to 15% of EDs. The intraclass correlation coefficient was 0.85 (95% confidence interval, 0.77–0.91) for vertical and 0.84 (95% confidence interval, 0.74–0.90) for horizontal ED measurements.
CONCLUSIONS:Cornea specialists showed good reliability in the measured EDs; however, depending on the threshold for clinical significance, a nontrivial percentage of cases have high interexaminer clinical variability.
The recent study by Hodi et al. published in the Journal of Clinical Oncology has evaluated unconventional response patterns during PD-1 inhibitor therapy using immune-related response criteria ...(irRC) in comparison with RECIST1.1, which constitutes an important step to further understand immune-related response phenomena. This commentary discusses the key observations in the study in terms of their implications and pitfalls, and describes unmet needs that remain to be addressed. The article also emphasizes the important role of tumor response criteria as a “common language” to describe the results of cancer treatment, and discusses future directions for further advances of the field of immuno-oncology.
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