Reproducibility of semiautomated body composition segmentation of abdominal computed tomography: a multiobserver study

Background Segmentation of computed tomography (CT) images provides quantitative data on body tissue composition, which may greatly impact the development and progression of diseases such as type 2 diabetes mellitus and cancer. We aimed to evaluate the inter- and intraobserver variation of semiautomated segmentation, to assess whether multiple observers may interchangeably perform this task. Methods Anonymised, unenhanced, single mid-abdominal CT images were acquired from 132 subjects from two previous studies. Semiautomated segmentation was performed using a proprietary software package. Abdominal muscle compartment (AMC), inter- and intramuscular adipose tissue (IMAT), visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) were identified according to pre-established attenuation ranges. The segmentation was performed by four observers: an oncology resident with extensive training and three radiographers with a 2-week training programme. To assess interobserver variation, segmentation of each CT image was performed individually by two or more observers. To assess intraobserver variation, three of the observers did repeated segmentations of the images. The distribution of variation between subjects, observers and random noise was estimated by a mixed effects model. Inter- and intraobserver correlation was assessed by intraclass correlation coefficient (ICC). Results For all four tissue compartments, the observer variations were far lower than random noise by factors ranging from 1.6 to 3.6 and those between subjects by factors ranging from 7.3 to 186.1. All interobserver ICC was ≥ 0.938, and all intraobserver ICC was ≥ 0.996. Conclusions Body composition segmentation showed a very low level of operator dependability. Multiple observers may interchangeably perform this task with highly reproducible results.

Classification of Pediatric Supracondylar Fractures: Comparison between the Gartland and the Lagrange & Rigault Classifications

Background The supracondylar fracture of the humerus is one of the most common fractures in pediatric age. Many classifications were proposed, with Gartland being the most widely used one and Lagrange and Rigault (L&R) the most used in French-speaking countries. Objectives The goal of this study was to compare the Wilkins-modified Gartland classification with the L&R classification in terms of reproducibility. Methods Three observers with similar training levels classified 35 fractures according to both classifications twice to evaluate both intra and interobserver variation. Results The mean intraobserver variation was 0.78 and 0.77 for Gartland and L&R classifications, respectively, and the mean interobserver variation was 0.55 and 0.62 for Gartland and L&R classifications, respectively. Conclusions Both classifications reveal adequate to usage in clinical and investigational practices, which is consistent with the literature.

Variability Over Time of Normal-Sized Fetal Renal Pelvis During the Second Trimester Scan

Purpose To investigate the variability of the normal-sized fetal renal pelvis (≤5 mm) over time and to analyze repeatability of measurements. Materials and Methods 98 fetal renal pelvises and 49 fetal urinary bladders were analyzed at a gestational age of 17–20 weeks at St. Olavs Hospital, Trondheim, Norway. The anterior-posterior diameter (APD) of the fetal renal pelvis and two diameters of the fetal bladder were measured with an interval of at least 30 min. Intra- and interobserver variations and variations over time and in association with bladder size were investigated. Results The mean difference in renal pelvis size between the first and second measurements was 0.09 mm (95% CI, −0.09 to 0.26 mm). The variation over time was ≤1 mm in 85% of cases and the renal pelvis was ≤4 mm in both the first and second examinations in 92% of cases. The intraclass correlation coefficient (ICC) was 0.54 (95% CI: 0.31 to 0.69). We did not observe any association between variation of bladder size and variation of APD. The difference in fetal renal pelvis size was ≤1 mm in 70% of observations for the first examiner and 58% for the second examiner. The intraobserver ICCs were 0.71 (95% CI: 0.62–0.78) and 0.60 (95% CI: 0.50–0.70) for the two observers respectively. The interobserver difference was ≤1 mm in 72% of cases and the interobserver ICC was 0.56 (95% CI: 0.34–0.71). Conclusion The variation of the APD of the fetal renal pelvis over time was small in fetuses with the APD in the lower range and can mainly be explained by intraobserver variation.

Large observer variation of clinical assessment of dyspnoeic wheezing children

BackgroundIn children with acute dyspnoea, the assessment of severity of dyspnoea and response to treatment is often performed by different professionals, implying that knowledge of the interobserver variation of this clinical assessment is important.ObjectiveTo determine intraobserver and interobserver variation in clinical assessment of children with dyspnoea.MethodsFrom September 2009 to September 2010, we recorded a convenience sample of 27 acutely wheezing children (aged 3 months–7 years) in the emergency department of a general teaching hospital in the Netherlands, on video before and after treatment with inhaled bronchodilators. These video recordings were independently assessed by nine observers scoring wheeze, prolonged expiratory phase, retractions, nasal flaring and a general assessment of dyspnoea on a Likert scale (0–10). Assessment was repeated after 2 weeks to evaluate intraobserver variation.ResultsWe analysed 972 observations. Intraobserver reliability was the highest for supraclavicular retractions (κ 0.84) and moderate-to-substantial for other items (κ 0.49–0.65). Interobserver reliability was considerably worse, with κ<0.46 for all items. The smallest detectable change of the dyspnoea score (>3 points) was larger than the minimal important change (<1 point), meaning that in 69% of observations a clinically important change after treatment cannot be distinguished from measurement error.ConclusionsIntraobserver variation is modest, and interobserver variation is large for most clinical findings in children with dyspnoea. The measurement error induced by this variation is too large to distinguish potentially clinically relevant changes in dyspnoea after treatment in two-thirds of observations. The poor interobserver reliability of clinical dyspnoea assessment in children limits its usefulness in clinical practice and research, and highlights the need to use more objective measurements in these patients.

Assessment of Technetium-99m Labeled Macroaggregated Albumin Rhinoscintigraphy for the Measurement of Nasal Mucociliary Transport Rate: Intratest, Interobserver, and Intraobserver Reproducibility

Objectives.The measurement of mucociliary transport velocity by rhinoscintigraphy with Tc-99m-macroaggregated albumin (99mTc-MAA) is reliable measure of mucociliary clearance. The aim of this study is to assess the intratest, interobserver, and intraobserver reproducibility of nasal mucociliary transport rate (NMTR) measurement.Materials and Methods.Twenty-two subjects were evaluated to determine intratest reproducibility and a group of 35 subjects was examined to determine inter- and intraobserver reproducibility. Rhinoscintigraphy with99mTc-MAA was used to measure NMTR in all study subjects. Paired NMTR measurements were compared using a range of statistical methodologies. Intraclass correlation coefficients (ICC) and repeatability coefficients and Bland-Altman plots were applied to assess the degree of intratest, interobserver, and intraobserver variation.Results.Statistical analysis of test and retest experiments demonstrated the statistical equivalence of intratest NMTR measurements, interobserver NMTR measurements, and intraobserver NMTR measurements. The intratest ICC, interobserver ICC, and intraobserver ICC were 0.96, 0.83, and 0.91, respectively, indicating that intratest and intraobserver reproducibility are excellent and interobserver reproducibility is good.Conclusions.Rhinoscintigraphy using99mTc-MAA results in highly reproducible measurement of NMTR. The use of radionuclide imaging in measuring NMTR results in excellent intratest and intraobserver reproducibility and good interobserver reliability.