Intraobserver Repeatability Research Articles

Pigment epithelial detachment composition indices (PEDCI) in neovascular age-related macular degeneration

We provide an automated analysis of the pigment epithelial detachments (PEDs) in neovascular age-related macular degeneration (nAMD) and estimate areas of serous, neovascular, and fibrous tissues within PEDs. A retrospective analysis of high-definition spectral-domain OCT B-scans from 43 eyes of 37 patients with nAMD with presence of fibrovascular PED was done. PEDs were manually segmented and then filtered using 2D kernels to classify pixels within the PED as serous, neovascular, or fibrous. A set of PED composition indices were calculated on a per-image basis using relative PED area of serous (PEDCI-S), neovascular (PEDCI-N), and fibrous (PEDCI-F) tissue. Accuracy of segmentation and classification within the PED were graded in masked fashion. Mean overall intra-observer repeatability and inter-observer reproducibility were 0.86 ± 0.07 and 0.86 ± 0.03 respectively using intraclass correlations. The mean graded scores were 96.99 ± 8.18, 92.12 ± 7.97, 91.48 ± 8.93, and 92.29 ± 8.97 for segmentation, serous, neovascular, and fibrous respectively. Mean (range) PEDCI-S, PEDCI-N, and PEDCI-F were 0.253 (0–0.952), 0.554 (0–1), and 0.193 (0–0.693). A kernel-based image processing approach demonstrates potential for approximating PED composition. Evaluating follow up changes during nAMD treatment with respect to PEDCI would be useful for further clinical applications.

Ultrasound-Based Grading System for Radiation-Induced Acute Breast Toxicity.

To introduce an ultrasound-based scoring system for radiation-induced breast toxicity and test its reliability. Breast ultrasound (BUS) was performed on 32 patients receiving breast radiotherapy (RT) to assess the radiation-induced acute toxicity. For each patient, both the untreated and irradiated breasts were scanned at five locations: 12:00, 3:00, 6:00, 9:00, and tumor bed to evaluate for heterogenous responses to radiation within the entire breast. In total, 314 images were analyzed. Based on ultrasound findings such as skin thickening, dermis boundary irregularity, and subcutaneous edema, a 4-level, Likert-like grading scheme is proposed: none (G0), mild (G1), moderate (G2), and severe (G3) toxicity. Two ultrasound experts graded the severity of breast toxicity independently and reported the inter- and intra-observer reliability of the grading system. Imaging findings were compared with standard clinical toxicity assessments using Common Terminology Criteria for Adverse Events (CTCAE). The inter-observer Pearson correlation coefficient (PCC) was 0.87 (95% CI: 0.83-0.90, P < .001). For intra-observer repeatability, the PCC of the repeated scores was 0.83 (95% CI: 0.78-0.87, P < .001). Imaging findings were compared with standard clinical toxicity assessments using CTCAE scales. The PCC between BUS scores and CTCAE results was 0.62 (95% CI: 0.35-0.80, P < .001). Among all locations, 6:00 and tumor bed showed significantly greater toxicity compared with 12:00 (P=.04). BUS can investigate the cutaneous and subcutaneous tissue changes after RT. This BUS-based grading system can complement subjective clinical assessments of radiation-induced breast toxicity with cutaneous and subcutaneous sonographic information.

Intra-individual comparison of two-dimensional shear wave elastography techniques using plane wave imaging and the multi-beam technique: are they interchangeable in measuring liver fibrosis?

This study compared two different two-dimensional shear wave elastography techniques-plane wave imaging (PWI) and multi-beam (MB) imaging-from the same vendor to evaluate liver fibrosis. In this prospective study, 42 patients with chronic liver disease who had recently undergone magnetic resonance elastography (<3 months) were enrolled, and their liver stiffness (LS) values were measured using PWI or MB. The LS values (kPa) were compared using the Wilcoxon rank-sum test. Inter-technique reproducibility and intra-observer repeatability were assessed using Bland-Altman analysis with 95% limits of agreement (LOA) and coefficients of variation (CVs). The cutoff values for predicting severe fibrosis (≥F3) were estimated using receiver operating characteristic curve (ROC) analysis, with magnetic resonance elastography as the reference standard. PWI exhibited technical failure in four patients. Therefore, 38 patients underwent both examinations. The LS values showed moderate agreement between PWI and MB (CV, 22.5%) and 95% LOA of -3.71 to 7.44 kPa. The MB technique showed good intra-observer agreement (CV, 8.1%), while PWI showed moderate agreement (CV, 11.0%). The cutoff values of PWI and MB for diagnosing ≥F3 were 12.3 kPa and 13.8 kPa, respectively, with areas under the ROC curve of 0.89 and 0.95 (sensitivity, 100% and 100%; specificity, 65.6% and 85.7%). The LS values significantly differed between PWI and MB, hindering their interchangeable use in longitudinal follow-up. Considering its low technical failure rate and better repeatability, the MB technique may be preferable for evaluating liver fibrosis in chronic liver disease patients.

851 REPEATABILITY OF BOLUS AND CONTINUOUS THERMODILUTION FOR ASSESSING CORONARY MICROVASCULAR FUNCTION

Abstract Introduction The bolus thermodilution-derived index of microcirculatory resistance (IMR) has emerged over years as the standard of reference to invasively define coronary microvascular dysfunction (CMD). However, the technique still presents some limitations, mainly related to the fact that manual injection of saline bolus accounts for some variance in the measurements. Continuous intracoronary thermodilution has been recently introduced as a tool to directly quantify absolute coronary flow and microvascular resistance both at rest and during hyperemia and has shown to be safe and operator independent. Microvascular resistance reserve (MRR), derived from continuous thermodilution, has been validated as novel index specific for microcirculation and independent from myocardial mass. Purpose To compare head-to-head the intra-observer repeatability of bolus and continuous thermodilution for assessing microvascular function. Methods Patients undergoing coronary angiography in the absence of obstructive coronary artery disease were prospectively enrolled. Bolus and continuous intracoronary thermodilution measurements were performed in duplicates in the left anterior descending artery (LAD). Patients were randomly assigned in a 1:1 ratio to undergo first bolus thermodilution or first continuous thermodilution assessment. Results A total of 102 patients were enrolled. Average FFR was 0.86±0.06. Coronary Flow Reserve (CFR) calculated with continuous thermodilution (CFRthermo) was significantly lower than bolus thermodilution-derived CFR (CFRbolus) (2.63±0.65 and 3.29±1.17, respectively, p&amp;lt;0.001). CFRthermo showed a lower variability and a higher agreement than CFRbolus (variability 12.74 ± 10.41% vs 31.26±24.85%, respectively, p&amp;lt;0.001; ICC= 0.78 (0.70-0.85) and 0.48 (0.32-0.62), respectively, p&amp;lt;0.001, Figure 1). Both MRR and IMR showed a good agreement (ICC 0.81 (0.74-0.87) and 0.80 (0.71-0.86)) but the variability of the MRR was significantly lower (12.44 ± 10.06% vs 24.24±19.27, respectively, p&amp;lt;0.001, figure 1). Reproducibility data of all indices derived from duplicated measurements of bolus and continuous thermodilution are reported in Figure 2. Conclusion Continuous intracoronary thermodilution has a higher repeatability than bolus thermodilution in the assessment of CMD.

A comparative assessment of intra- and inter- observer repeatability of three widely used software packages for the quantification of defect size in stress myocardial perfusion scintigraphy.

To assess the intra- and inter-observer repeatability of popular software packages for the quantitative determination of abnormality size in stress myocardial perfusion scintigraphy. A total of 182 tomographic stress myocardial perfusion scans were processed in duplicate by an experienced and trainee observer to assess SSSext (summed stress score multiplied by 100/68) and total defect extent (TDE), as % of the left ventricle, with 4 dimension-myocardial (4DM), emory cardiac toolbox (ECTb) and quantitative perfusion SPECT (QPS) packages. The Bland-Altman (B-A) analysis and Lin's concordance correlation coefficient (CCC) were used to assess agreement. In SSSext's intra-observer repeatability, CCC showed substantial agreement for 4DM and QPS, and moderate agreement for ECTb for both observers. In inter-observer repeatability, CCC revealed substantial agreement for 4DM and QPS, and poor agreement for ECTb. Regarding TDE, CCC showed substantial intra-observer repeatability for both operators using all packages, while the inter-observer repeatability was substantial for 4DM and QPS, and moderate for ECTb.In SSSext's intra-observer repeatability for 4DM, ECTb and QPS, the B-A analysis provided (mean±1.96SD of paired measurements) 0.0±4.3, 0.2±7.8, -0.6±7.6 for the experienced physician and 0.2±5.9, 0.0±7.5, -0.5±5.4 for the trainee, respectively; in inter-observer repeatability it provided 0.2±5.4, 0.1±9.6, 0.2±8.1, respectively. Regarding TDE, the B-A values for intra-observer repeatability were 0.1±5.2, 0.1±7.9, 0.1±2.8 for the experienced reader and 0.3±6.6, -0.1±6.4, -0.1±2.4 for the trainee, respectively; in inter-observer agreement the B-A provided 0.6±6.4, -0.2±10.3, -0.1±4.3, respectively. Considerable differences in intra- and inter- observer agreement were noted for the quantitative determination of defect size using widely employed software packages, suggesting limitations in the clinical use of these measurements. Quantitative perfusion SPECT appears preferable, but with no significant advantage over 4DM. There were no significant differences between the observers.

Repeatability and correlation of corneal biomechanical measurements obtained by Corvis ST in orthokeratology patients

PurposeTo evaluate the repeatability of the corneal biomechanical measurements obtained by Corvis ST in post-orthokeratology patients and analyze the correlation between the biomechanical and ocular parameters. MethodsFifty-one eyes of 51 myopic subjects were included in this study. The biomechanical parameters were assessed using Corvis ST. Repeatability was assessed using one-way ANOVA based on within-subject standard deviation (Sw), repeatability coefficient (RC), intraclass correlation coefficient (ICC) and correlation of variation (CoV). The correlation was evaluated using Pearson correlation analysis. ResultsAll parameters measured by Corvis ST, except length of flattened cornea at the first and second applanations (A1L and A2L), showed a good intraobserver repeatability after a 3-month follow-up period. The ICC values for A1L and A2L were 0.444 and 0.654, whereas the other parameters were higher than 0.8. Similar trends were obtained for CoV, wherein the CoV values for A1L and A2L were greater than 13 %. The corneal biomechanical parameters were correlated with age, refraction, axial length (AL), steep and flat keratometry before and after orthokeratology, and central corneal thickness (CCT). Following orthokeratology treatment, post-keratometry demonstrated a higher correlation with stiffness parameter at first applanation (SP-A1), velocity of corneal apex at the first applanation (A1V), and radius than pre-keratometry, which showed a weak correlation with SP-A1. ConclusionCorneal biomechanical parameters assessed using Corvis ST demonstrated a good repeatability, except A1L and A2L. The corneal biomechanical parameters were correlated with age, refraction, AL and pre- and post-keratometry. Thus, Corvis ST is a suitable device for investigating biomechanical parameter.

Variability, Validity and Operator Reliability of Three Ultrasound Systems for Measuring Tissue Stiffness: A Phantom Study

Introduction Ultrasound elastography is a method of measuring soft tissue stiffness to detect the presence of pathology. There are several ultrasound elastography devices on the market. The aim of this study was twofold. Firstly, to determine the validity of three different ultrasound systems used to measure tissue stiffness. Secondly, to determine the operator reliability and repeatability when using these three systems. Materials and methods Two observers undertook multiple stiffness measurements from a phantom model using three different ultrasound systems; the LOGIQ E9, the Aixplorer, and the Acuson S2000. The phantom model had four cylindrical-shaped inclusions (Type 1-4) of increasing stiffness values and diameter embedded within. The background phantom stiffness was fixed. The mean, standard deviation, and coefficient of variation (CV) were calculated from measured stiffness readings per diameter per inclusion. Intra-observer variability was assessed. The validity of the measured stiffness value was assessed by calculating the difference between the measured elasticities and actual phantom elasticities. Bland-Altman plots with limits of agreement were used to display the inter-observer agreement. The intraclass correlation coefficients (ICC) were used to measure intra-observer, inter-observer, and inter-system reliability. Results Each observer undertook 1020 measurements. All three systems generally underestimated the stiffness values for the inclusions; the higher the actual stiffness value, the more significant the underestimation. The percentage difference between measured stiffness and actual stiffness varied from -79.1% to 12.7%. The intra-observer variability was generally less than 5% for observers using the LOGIQ E9 and the Aixplorer systems but more than 10% over the stiffer inclusions (Types 3 and 4) for the Acuson system. There was 'almost perfect' intra-observer reliability and repeatability for both the LOGIQ E9 and the Aixplorer systems; this was 'moderate' for the Acuson system over specific inclusions. For all systems, there was 'almost perfect' inter-observer reliability and repeatability between Observer A and Observer B. The inter-system reliability and repeatability were 'almost perfect' between the LOGIQ E9 system and the Aixplorer system but 'poor' and 'moderate' when the Acuson system was matched with the LOGIQ E9 system and the Aixplorer system, respectively. Conclusion This study has demonstrated that the Acuson, LOGIQ E9, and Aixplorer ultrasound systems have low variability, high reproducibility, and good intra-observer and inter-observer reliability when used to measure tissue stiffness. However, they all underestimated the stiffness values during this in vitro study. This study also revealed that not all ultrasound systems are comparable when measuring tissue stiffness, with some having better inter-system reliability than others. Ongoing standardization of technology is required at the manufacturer level.

Repeatability and reproducibility of the interpretation of intradermal test results in dogs with atopic dermatitis.

Background - There is lack of studies evaluating the repeatability and reproducibility of the interpretation of intradermal testing in dogs with atopic dermatitis (AD). Objectives - To evaluate the repeatability and reproducibility of the interpretation of intradermal test results in dogs with AD. For comparison, the repeatability of allergen-specific immunoglobulin (Ig)E serology also was examined. Materials and methods - Twenty dogs with AD were used. Intradermal test included injections of known negative and positive controls, and of 25 masked injections of 10 allergens/controls, that were selected randomly and injected at random positions. Reactions to the 25 masked allergens/controls were scored (positive/negative) subjectively by three independent examiners followed by an objective assessment. Allergen-specific IgE serology was performed in blinded duplicate samples collected from all dogs for nine of 10 of the same allergens. Results - Kappa values of intraobserver repeatability (≥2 injections of the same allergen to different positions of the same dog) varied between -0.53 and 0.8 (subjective evaluations), and between 0.03 and 1 (objective evaluation). When the repeatability of the serological test was examined k= 0.91. Kappa values for the interobserver reproducibility (objective and three subjective evaluations of the same allergen injected at the same position of the same dog) varied between 0.6 and 0.74 (overall 0.67). Conclusions and clinical relevance - Intraobserver repeatability of the subjective and objective evaluation of IDT results varied from good to poor and depended on the number of times the same allergen was injected, whereas interobserver reproducibility varied from substantial to moderate. Further studies are needed to optimise the repeatability and reproducibility of IDT in dogs.

Immersion ultrasonography improves the repeatability of cephalic vein diameter measurements for inexperienced operators

Objective To reduce the empirical dependence of ultrasound measurement of the cephalic vein diameter, improve the repeatability of measurements for inexperienced operators, and provide a new method for inexperienced operators. Methods Operators without ultrasound experience used contact ultrasound and immersion ultrasound to measure the diameter of the cephalic vein. The intraobserver and interobserver repeatability of measurements obtained via the two methods were analyzed. Results The intraobserver and interobserver repeatability of the cephalic vein diameter measured via contact ultrasound by inexperienced operators were average, with intraclass correlation coefficients (ICCs) of 0.572 (95% CI: 0.239–0.759) and 0.405 (95% CI: −0.057–0.666), respectively. The intraobserver and interobserver reproducibility of the cephalic vein diameter measured by immersion ultrasound were very good, with ICCs of 0.955 (95% CI: 0.922–0.975) and 0.943 (95% CI: 0.900–0.967), respectively. In the Bland–Altman diagram of the intraobserver and interobserver agreement of the immersion ultrasound measurements of the cephalic vein diameter, 96% of the points fell within the 95% limits of agreement. Conclusion Immersion ultrasonography can be used to measure the cephalic vein diameter while reducing the dependence of the results on operator experience; inexperienced operators can achieve very good repeatability.

Repeatability of bolus and continuous thermodilution for assessing coronary microvasculatory function

Abstract Introduction The bolus thermodilution-derived index of microcirculatory resistance (IMR) has emerged over years as the standard of reference to invasively define coronary microvascular dysfunction (CMD). However, the technique still presents some limitations, mainly related to the fact that manual injection of saline bolus accounts for some variance in the measurements. Continuous intracoronary thermodilution has been recently introduced as a tool to directly quantify absolute coronary flow and microvascular resistance both at rest and during hyperemia and has shown to be safe and operator independent. Microvascular resistance reserve (MRR), derived from continuous thermodilution, has been validated as novel index specific for microcirculation and independent from myocardial mass. Purpose To compare head-to-head the intra-observer repeatability of bolus and continuous thermodilution for assessing microvascular function. Methods Patients undergoing coronary angiography in the absence of obstructive coronary artery disease were prospectively enrolled. Bolus and continuous intracoronary thermodilution measurements were performed in duplicates in the left anterior descending artery (LAD). Patients were randomly assigned in a 1:1 ratio to undergo first bolus thermodilution or first continuous thermodilution assessment. Results A total of 102 patients were enrolled. Average FFR was 0.86±0.06. Coronary Flow Reserve (CFR) calculated with continuous thermodilution (CFRthermo) was significantly lower than bolus thermodilution-derived CFR (CFRbolus) (2.63±0.65 and 3.29±1.17, respectively, p&amp;lt;0.001). CFRthermo showed a lower variability and a higher agreement than CFRbolus (variability 12.74±10.41% vs 31.26±24.85%, respectively, p&amp;lt;0.001; ICC= 0.78 (0.70–0.85) and 0.48 (0.32–0.62), respectively, p&amp;lt;0.001, Figure 1). Both MRR and IMR showed a good agreement (ICC 0.81 (0.74–0.87) and 0.80 (0.71–0.86)) but the variability of the MRR was significantly lower (12.44±10.06% vs 24.24±19.27, respectively, p&amp;lt;0.001, Figure 1). Reproducibility data of all indices derived from duplicated measurements of bolus and continuous thermodilution are reported in Table 2. Conclusion Continuous intracoronary thermodilution has a higher repeatability than bolus thermodilution in the assessment of CMD. Funding Acknowledgement Type of funding sources: None.

Results of using multiplanar reconstructed CT images for assessing elbow joint osteoarthritis in dogs are consistent with results of radiographic assessment.

To compare osteoarthritis scores assigned through radiographic evaluation of 18 anatomic regions in the elbow joint with scores assigned through evaluation of 3-D maximum intensity projection (MIP), 3-D surface rendering (TSR), and multiplanar reconstructed (MPR) CT images, and to evaluate intraobserver and interobserver agreement of radiographic and CT scoring. Radiographic and CT images of 39 elbow joints in 20 dogs. Images were anonymized and graded independently by 5 observers. One observer graded 12 elbow joints 3 times. Intraobserver consistency and repeatability, interobserver agreement, consistency among methods, and bias between methods were calculated. The most severe changes were observed at the proximal aspect of the anconeal process, and the medial and cranial aspects of the medial coronoid process. Intraobserver consistency was moderate or better for 11/16 regions with MIP images, 11/16 regions with TSR images, 17/18 regions with MPR images, and 14/18 regions with radiographic images. Interobserver agreement was moderate or better for 5/16 regions with MIP images, 9/16 regions with TSR images, 12/18 regions with MPR images, and 6/18 regions with radiographic images. Mean scores from CT-based methods were higher than mean radiographic scores. Assessments of osteoarthritis severity in the elbow joints of dogs obtained by examining radiographic images were generally consistent with assessments obtained by examining CT scans. MPR scores were more consistent and more comparable to radiographic scores than were MIP or TSR scores.

Inter-transducer variability of ultrasound image quality in obese adults: Qualitative and quantitative comparisons

PurposeAcquiring high-quality ultrasound images of deep abdominal organs and vasculatures in obese adults (BMI >30 kg/cm2) is considered challenging. The aim of the study was to assess the inter-transducer variability in B-mode and color Doppler image quality from four commercial ultrasound transducers through qualitative and quantitative analyses. MethodsFour curvilinear transducers on three ultrasound scanners were used to acquire B-mode and color Doppler images of deep abdominal structures in 15 obesity ≥ class II (BMI >35 kg/cm2) adults. Using visual-qualitative assessment and an offline image processing software, visual-qualitative score and quantitative mean pixel values of B-mode images, and color area ratios of color Doppler images were calculated. Differences in these values among the transducers were analyzed using one-way ANOVA. The intra- and inter-observer reliability of visual-qualitative assessment and offline image processing was tested using the intraclass correlation coefficient (ICC). ResultsDifferences in visual-qualitative score, mean pixel value of B-mode images, and color area ratio of color Doppler images among the four transducers were significant (p < 0.001). Transducer −4 produced the highest quality of B-mode (45–53% improvement) and color Doppler (22–73% improvement) images among the transducers. Intra-observer repeatability and inter-observer reproducibility were higher with performing offline image processing than visual-qualitative assessment (ICC: 0.97–0.99 versus ICC: 0.76–0.97). ConclusionThere was significant image quality variability between different transducers. Transducer −4, a transducer designed specifically for high BMI patients, had the highest quality B-mode and color Doppler images compared to the other transducers lending to improved ultrasonographic visualization in obese patients.

Clinical evaluation of the Multimapping technique for simultaneous myocardial T1 and T2 mapping.

The Multimapping technique was recently proposed for simultaneous myocardial T1 and T2 mapping. In this study, we evaluate its correlation with clinical reference mapping techniques in patients with a range of cardiovascular diseases (CVDs) and compare image quality and inter- and intra-observer repeatability. Multimapping consists of an ECG-triggered, 2D single-shot bSSFP readout with inversion recovery and T2 preparation modules, acquired across 10 cardiac cycles. The sequence was implemented at 1.5T and compared to clinical reference mapping techniques, modified Look-Locker inversion recovery (MOLLI) and T2 prepared bSSFP with four echo times (T2bSSFP), and compared in 47 patients with CVD (of which 44 were analyzed). In diseased myocardial segments (defined as the presence of late gadolinium enhancement), there was a high correlation between Multimapping and MOLLI for native myocardium T1 (r2 = 0.73), ECV (r2 = 0.91), and blood T1 (r2 = 0.88), and Multimapping and T2bSSFP for native myocardial T2 (r2 = 0.80). In healthy myocardial segments, a bias for native T1 (Multimapping = 1,116 ± 21 ms, MOLLI = 1,002 ± 21, P < 0.001), post-contrast T1 (Multimapping = 479 ± 31 ms, MOLLI = 426 ± 27 ms, 0.001), ECV (Multimapping = 21.5 ± 1.9%, MOLLI = 23.7 ± 2.3%, P = 0.001), and native T2 (Multimapping = 48.0 ± 3.0 ms, T2bSSFP = 53.9 ± 3.5 ms, P < 0.001) was observed. The image quality for Multimapping was scored as higher for all mapping techniques (native T1, post-contrast T1, ECV, and T2bSSFP) compared to the clinical reference techniques. The inter- and intra-observer agreements were excellent (intraclass correlation coefficient, ICC > 0.9) for most measurements, except for inter-observer repeatability of Multimapping native T1 (ICC = 0.87), post-contrast T1 (ICC = 0.73), and T2bSSFP native T2 (ICC = 0.88). Multimapping shows high correlations with clinical reference mapping techniques for T1, T2, and ECV in a diverse cohort of patients with different cardiovascular diseases. Multimapping enables simultaneous T1 and T2 mapping and can be performed in a short breath-hold, with image quality superior to that of the clinical reference techniques.

Intra- and interobserver assessments of intestinal wall thickness and segmentations from transverse sections of feline abdominal ultrasound images.

Measurements of intestinal wall thicknesses from ultrasound imaging (US) are routinely used to support diagnoses of intestinal disorders in cats, however published studies describing observer agreement are currently lacking. The aim of this retrospective, observer agreement study was to quantify inter- and intraobserver repeatability and agreement in the measurement of intestinal wall layer thicknesses and the segmentation of transverse sections of small intestines in US images of 20 cats. Intestinal wall layer thickness measurements of the mucosa, submucosa, muscularis, serosa layer, and total thickness of these layers were performed on five cats with small cell epitheliotropic lymphoma, five with inflammatory bowel disease, and 10 with other conditions. Thickness measurements and the segmentation encompassing the serosa layer were obtained from five observers four times non-sequentially. The average standard deviation in thickness measurements (95% confidence interval) in the mucosa, submucosa, muscularis, serosa, and total thickness were 0.35 (0.07-0.95), 0.24 (0.07-0.52), 0.22 (0.06-0.49), 0.20 (0.05-0.49), and 0.57 (0.11-1.60) mm, respectively. The average intraclass correlation coefficients, which estimates the degree of consistency in thickness measurements and segmentation areas for each observer, ranged from 0.355 to 0.870 and 0.850 to 0.993, respectively. The interclass correlation coefficient, which estimates the degree of consistency when measuring a thickness or segmentation area over all observers ranged from 0.115 to 0.753, and 0.811 to 0.902, respectively. The overall average Dice Coefficient, which estimates the extent of overlap of the segmentations for all observers was 0.957 (0.933 to 0.972). Our results suggest segmentations of small intestines have a higher interobserver agreement than measurements of intestinal wall thicknesses.

Repeatability of radiographic assessments for feline hip dysplasia suggest consensus scores in radiology are more uncertain than commonly assumed

Variation in the diagnostic interpretation of radiographs is a well-recognised problem in human and veterinary medicine. One common solution is to create a ‘consensus’ score based on a majority or unanimous decision from multiple observers. While consensus approaches are generally assumed to improve diagnostic repeatability, the extent to which consensus scores are themselves repeatable has rarely been examined. Here we use repeated assessments by three radiologists of 196 hip radiographs from 98 cats within a health-screening programme to examine intra-observer, inter-observer, majority-consensus and unanimous-consensus repeatability scores for feline hip dysplasia. In line with other studies, intra-observer and inter-observer repeatability was moderate (63–71%), and related to the reference assessment and time taken to reach a decision. Consensus scores did show reduced variation between assessments compared to individuals, but consensus repeatability was far from perfect. Only 75% of majority consensus scores were in agreement between assessments, and based on Bayesian multinomial modelling we estimate that unanimous consensus scores can have repeatabilities as low as 83%. These results clearly show that consensus scores in radiology can have large uncertainties, and that future studies in both human and veterinary medicine need to include consensus-uncertainty estimates if we are to properly interpret radiological diagnoses and the extent to which consensus scores improve diagnostic accuracy.

Three-dimensional macroscopical quantification of plaque accumulation on implant-supported fixed complete dental prostheses surfaces: A methodological pilot study

Statement of problemArea calculation is the primary method for quantitatively analyzing accumulated plaque on the intaglio surfaces of implant-supported fixed complete dental prostheses (IFCDPs). However, the classic calculation method for stained dental plaque is based on two-dimensional (2D) photographs, which could mislead the three-dimensional (3D) representation of an object’s actual morphology, especially when a surface is not flat. PurposeThis pilot in vitro study, used for methodological purposes, evaluated the repeatability and precision of a 3D area calculation method to analyze simulated accumulated biofilm on the intaglio surfaces of an IFCDP. Material and methodsThe titanium framework of an IFCDP with a smooth intaglio surface was prepared with 8 milled sites and scanned by microcomputed tomography. Out of these, 4 sites were cubic (set sides lengths=1, 2, 3, and 4 mm), and 4 sites were hemispherical (set diameters=1, 2, 3, and 4 mm). A green-colored aerosol was sprayed onto the carved-out intaglio sites. The framework intaglio surface was 3D-scanned (n=10) and 2D-photographed (n=10) at 10 different photo angles. Two raters twice measured the 3D and 2D data from the carved-out sites’ green-colored area one week apart. Intraobserver repeatability and interobserver reliability were evaluated with an independent t test. The deviation between the measurements and the microtomography values was calculated. Pearson’s correlation coefficient (r) evaluated the repeatability of multiple measurements. A standard level of significance was set at α=.05. ResultsThe differences between the 2D photographs and the microtomography values were statistically significant (P<.001), whereas the differences between the 3D scans and the microtomography values were not significant (P=.063). The overall differences between the microtomography values and the 3D measurements were smaller (2.15 ±2.30 mm2 vs. 18.91 ±22.78 mm2, P=.055) than the differences between the microtomography values and the 2D measurements. The percentage differences between the microtomography values and the 3D measurements were significantly smaller (10.41 ±8.33% vs. 65.66 ±19.22%, P<.001) than the microtomography differences values with the 2D measurements. The measurement differences between the microtomography value and the 3D measured hemispherical site data were significantly smaller than the measurement differences between the microtomography values and the 3D measured cubical site data (P=.026). The 2D method had “poor” repeatability among the 10 different shot angles (r=0.391, P<.001), whereas the 3D method had “good” repeatability among the 10 scans (r=0.999, P<.001). ConclusionsAn irregular intaglio surface of an IFCDP could accurately and repeatedly be recorded and analyzed by a 3D area calculation method. This color-matching assessment of the topological environment is expected to be adopted in future studies.

Feasibility of ultrasonographic hepatic parenchymal attenuation imaging in healthy Beagles.

To investigate the clinical feasibility of attenuation imaging of the hepatic parenchyma in healthy dogs, identify technical factors that influence measured attenuation coefficients, and determine intraobserver repeatability of measurements. 10 healthy Beagles. Attenuation coefficients were calculated for various measurement sites (left vs central division of the liver), scanning planes (transverse vs sagittal plane), scanning depths (10 to 20 mm vs 20 to 30 mm), scanning approaches (intercostal vs subcostal approach), and breathing conditions (free breathing vs breath holding at end expiration). Intraoperator intraday and interday reliability was assessed by computing intraclass correlation coefficients. Attenuation coefficients were not influenced significantly by scanning plane (P = .120 to 1.000), measurement site (P = .292 to .848), or breathing condition (P = .166). However, coefficients were significantly (P < .01) less with deeper scanning depths and significantly (P < .05) more for the subcostal approach than the intercostal approach. The intraday and interday intraclass correlation coefficients showed good repeatability (0.799 and 0.771, respectively), regardless of the scanning plane and measurement site. Scanning the central division of the liver with the right intercostal approach at a depth of 10 to 20 mm from the liver capsule yielded good reliability. Attenuation imaging was a feasible technique for evaluating the hepatic parenchyma in healthy dogs with good repeatability. Measured attenuation coefficients were not affected by the scanning plane, measurement site, or breathing condition.

SWEmean of Quadriceps, a Potential Index of Complication Evaluation to Patients with Chronic Obstructive Pulmonary Disease.

PurposeTo develop a potential quadriceps’ index of complication evaluation for patients with chronic obstructive pulmonary disease (COPD) which is simple, convenient, and quantifiable.Patients and MethodsWe conducted a prospective study of 59 patients with COPD and 56 healthy controls recruited by the Chengdu First People’s Hospital. Grayscale ultrasound (US) of the rectus femoris was performed to measure thickness (RFthick) and cross-sectional area (RFcsa). Shear wave elastography was used to determine the mean elasticity index (SWEmean) of the rectus femoris (SWERFmean), vastus lateralis (SWEVLmean) and vastus medialis (SWEVMmean). Clinical features included dyspnea index score (modified British Medical Research Council (MMRC) score), COPD Assessment Test (CAT), the Five-Repetition Sit-to-Stand Test (5STS) and the Six-Minute Walk Test (6MWT). We compared the differences between US parameters and SWEmean in healthy controls and COPD patients. We also described the correlation between US parameters, SWEmean and clinical features of patients with COPD.ResultsThe intra-observer repeatability for the performance of using SWE to measure quadriceps stiffness was excellent (intraclass correlation coefficient (ICC)>0.75, p < 0.001). There was a statistically significant difference in the SWEmean of the quadriceps (p < 0.001), but no significant difference in terms of RFthic and RFcsa (p > 0.05) between healthy controls and COPD patients. The SWERFmean was positively correlated with the 6MWT (r = 0.959, p < 0.001), and negatively related to the mMRC (r=−0.825, p < 0.001), CAT (r=−0.993, p < 0.001) and 5STS (r=−0.936, p < 0.001). However, the RFthic, RFcsa, SWEVLmean and SWEVMmean were not correlated with clinical features (p > 0.05).ConclusionAs a supplement to US, SWE reflects changes of stiffness in the quadriceps of COPD patients, and can expanding the dimension of US for assessing the quadriceps. Furthermore, SWEmean was associated with clinical features, and represents a potential index with which to reflect the clinical features of COPD patients.

The feasibility and safety of stepwise protocol in cardiopulmonary exercise testing-exercise stress echocardiography for subjects with heart failure.

Exercise stress testing using a ramp protocol has been favored for cardiopulmonary exercise testing (CPX) in patients with heart failure (HF). However, the stepwise protocol for CPX was preferred for its possible combination with exercise stress echocardiography (ESE). We, therefore, investigated the feasibility and safety of using a stepwise protocol for CPX-ESE in patients with HF. Ambulatory outpatients with chronic HF were enrolled for a symptom-limited stepwise bicycle exercise test in the semi-supine position on a cycle ergometer. The test was started at a workload of 30 W and increased by 15 W every 3 minutes until maximal exertion. The echocardiographic and respiratory variables and any complications during the exercise were recorded. Among a total of 36 participants (age 61.2 ± 12.4 years; 69.4% men), all subjects achieved anerobic threshold during CPX-ESE and reached 72.3% of the age-predicted peak heart rate. The peak oxygen consumption was 14.7 mL/kg/min, and the peak RER was 1.25. There were no severe adverse complications, and only two minor rhythmic events were reported: nonsustained supraventricular tachycardia and isolated ventricular premature beats. The echocardiographic images acquired at each stage were of good quality in 92.6% of all acquisitions, and the intra-observer and interobserver repeatability was >80%. The stepwise protocol, with an initial workload of 30 W, followed by 15 W increments every 3 minutes, was feasible and provided an adequate stress load for patients with HF. This exercise stress modality was safe and well-tolerated.

Transvaginal Two-Dimensional Ultrasound Evaluation as a Screening Tool for Levator ani Muscle Avulsion in Postpartum Women.

To evaluate the agreement between two-dimensional transvaginal ultrasound (2D-TVUS) and transperineal tomographic ultrasound imaging on three-dimensional (3D) volume in diagnosing levator ani muscle (LAM) avulsion of postpartum women. Furthermore, we tested the repeatability of the 2D-TVUS in measuring the LAM thickness. A retrospective study was performed using the data sets from postpartum women. One doctor measured the thickness of the LAM on the images at the attachment to the arcus tendinous levator ani and the middle part using the 2D-TVUS ultrasound data sets of postpartum women. These women were examined twice, at 42-56 days and 3-6 months postpartum. Intra-observer repeatability was expressed using intraclass correlation coefficients (ICCs). The other doctor judged whether there was avulsion in the LAM on the 2D-TVUS and transperineal tomography imaging on the 3D volume. The inter-method agreement was determined using Cohen's kappa coefficient (k). Thickness measurements of the middle part and attachment of the LAM by 2D-TVUS showed excellent and good intra-observer repeatability (ICC 0.84; 95% CI, 0.76-0.88, and ICC 0.74; 95% CI, 0.67-0.84, respectively). The overall agreement was 92% (Cohen's kappa was 0.79) between 2D-TVUS and transperineal tomographic imaging. Compared to transperineal tomographic imaging in the diagnosis of LAM avulsion, the diagnostic sensitivity of 2D-TVUS was 91.7%, the specificity was 92.1%. The 2D-TVUS technique, a simple and reproducible method for assessing LAM avulsion, may be helpful as a screening tool for LAM avulsion of postpartum women.