Inexperienced Observers Research Articles

A Novel ImageJ Macro for Automated Cell Death Quantitation in the Retina.

TUNEL assay is widely used to evaluate cell death. Quantification of TUNEL-positive (TUNEL+) cells in tissue sections is usually performed manually, ideally by two masked observers. This process is time consuming, prone to measurement errors, and not entirely reproducible. In this paper, we describe an automated quantification approach to address these difficulties. We developed an ImageJ macro to quantitate cell death by TUNEL assay in retinal cross-section images. The script was coded using IJ1 programming language. To validate this tool, we selected a dataset of TUNEL assay digital images, calculated layer area and cell count manually (done by two observers), and compared measurements between observers and macro results. The automated macro segmented outer nuclear layer (ONL) and inner nuclear layer (INL) successfully. Automated TUNEL+ cell counts were in-between counts of inexperienced and experienced observers. The intraobserver coefficient of variation (COV) ranged from 13.09% to 25.20%. The COV between both observers was 51.11 ± 25.83% for the ONL and 56.07 ± 24.03% for the INL. Comparing observers' results with macro results, COV was 23.37 ± 15.97% for the ONL and 23.44 ± 18.56% for the INL. We developed and validated an ImageJ macro that can be used as an accurate and precise quantitative tool for retina researchers to achieve repeatable, unbiased, fast, and accurate cell death quantitation. We believe that this standardized measurement tool could be advantageous to compare results across different research groups, as it is freely available as open source.

OP‐5 INTEROBSERVER VALIDITY OF THE REFLUX FINDING SCORE FOR INFANTS (RFS‐I) IN FLEXIBLE VERSUS RIGID LARYNGOSCOPY.

Background:The Reflux Finding Score for Infants (RFS‐I) was developed to objectively assess signs of laryngopharyngeal reflux (LPR). Based on review of flexible laryngoscopic videos, only moderate inter‐ and highly variable intraobserver reliability was found. We hypothesized that examination of the infant larynx with rigid laryngoscopy would provide better agreement. AIM: to assess the validity of the RFS‐I in the detection of LPR‐related findings using flexible versus rigid laryngoscopy.Methods:Thirty consecutive infants underwent flexible and rigid laryngoscopy. Based on the recorded videos, RFS‐I was scored by 4 otorhinolaryngologists, 2 otorhinolaryngology fellows, and 2 inexperienced observers. Videos were presented in a randomized order, blinded for clinical profile and findings during initial examination. Observers were provided an instruction sheet prior to evaluation. For categorical data, agreement was calculated using Cohen's kappa (2 observers) and Fleiss’ kappa (>2 observers). For ordinal data the intraclass correlation coefficient (ICC) was used.Results:Of 30 included patients (17 M; median age 7.5 (0–19.8) months), main reasons for referral were: stridor (n = 15,50%), ALTE/apneas (n = 7,23.3%), follow‐up of laryngeal abnormalities (n = 6,20%), aspiration (n = 5,16.7%), and other indications (n = 7,23.3%). Overall interobserver agreement of the RFS‐I was moderate for both flexible (ICC = 0.60, [95%CI 0.44–0.76]) and rigid (ICC = 0.42, [95%CI 0.26–0.62] laryngoscopy. There were no significant differences in agreement on overall RFS‐I scores and individual RFS‐I items for flexible versus rigid laryngoscopy. We did observe higher overall agreement amongst the 2 inexperienced observers for rigid (ICC = 0.40, [95%CI 0.03–0.67]), compared to flexible (ICC = 0.11, [95%CI 0.17–0.41]) laryngoscopy, albeit not significant. Comparing RFS‐I results for flexible versus rigid laryngoscopy per observer, agreement ranged from no to substantial agreement (k = ‐0.16–0.63, mean k = 0.22) and the observed agreement (not adjusted for chance) was 0.08–0.35%.Conclusions:Interobserver agreement of the RFS‐I was only moderate and did not differ between flexible and rigid laryngoscopy. This indicates that the RFS‐I should not be used with flexible, nor rigid laryngoscopy to detect signs of LPR.

Near‐infrared laparoscopic fluorescence to guide fascial plane identification in total mesorectal excision for rectal cancer: A Video Vignette

Fluorescence lymph node mapping in colorectal cancer has most often being examined for utility in its identification of specific nodes either within or without standard resection fields. Indeed, we have detailed is use elsewhere in this supplement for determination of potentially significant lymph node basins on the pelvic side wall 1 and also previously regarding mescolic node mapping for colon cancer 2. Others have suggested its incorporation alongside TEM resection 3 where the mesorectal nodes may be selectively targetted from within the rectum via the mural excision site. However it may also be of more elementary value in simply guiding the surgeon easily and efficently along embryological planes in order to ensure explicit intraoperative clarity of dissection in total mesorectal or complete mesocolic excision (TME or CME respectively). It may also guide the level of high arterial ligation to secure inclusion of the apex node within the resected specimen. The associated video demonstrates this. The concept is based on the fact that submucosal injection of 2–3 ml indocyanine green (ICG) at the tumor site will provide a depot of dye that continally and passively leaches into and through the lymphatics and nodal basin within the fascial compartment targeted with TME or CME surgery. While early laparoscopic assessment may allow identification of the first draining lymph node, re-examination of the same areas later in the operation will show additional and perhaps all of the lymph nodes within the fascial envelope being resected. This can help guide the surgeon or interested and especially perhaps inexperienced observers, trainees or students in understanding the embryological planes required for effective and efficient oncological surgery. This may be especially useful when the rectum and mesorectum are being mobilised and also for determining precisely the level of arterial ligation to ensure the highest node is included and specifically labelled with the specimen sent for pathological analysis. The authors have no conflicts of interest to declare. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.

Data Reduction with the MIKE Spectrometer

This manuscript describes the design, usage, and data-reduction pipeline developed for the Magellan Inamori Kyocera Echelle (MIKE) spectrometer used with the Magellan telescope at the Las Campanas Observatory. We summarize the basic characteristics of the instrument and discuss observational procedures recommended for calibrating the standard data products. We detail the design and implementation of an IDL-based data-reduction pipeline for MIKE data (since generalized to other echelle spectrometers, e.g., Keck/HIRES, VLT/UVES). This includes novel techniques for flat-fielding, wavelength calibration, and the extraction of echelle spectroscopy. Sufficient detail is provided in this manuscript to enable inexperienced observers to understand the strengths and weaknesses of the instrument and software package and an assessment of the related systematics.

Categorical facilitation with equally discriminable colors

This study investigates the impact of language on color perception. By categorical facilitation, we refer to an aspect of categorical perception, in which the linguistic distinction between categories affects color discrimination beyond the low-level, sensory sensitivity to color differences. According to this idea, discrimination performance for colors that cross a category border should be better than for colors that belong to the same category when controlling for low-level sensitivity. We controlled for sensitivity by using colors that were equally discriminable according to empirically measured discrimination thresholds. To test for categorical facilitation, we measured response times and error rates in a speeded discrimination task for suprathreshold stimuli. Robust categorical facilitation occurred for five out of six categories with a group of inexperienced observers, namely for pink, orange, yellow, green, and purple. Categorical facilitation was robust against individual variations of categories or the laterality of target presentation. However, contradictory effects occurred in the blue category, most probably reflecting the difficulty to control effects of sensory mechanisms at the green-blue boundary. Moreover, a group of observers who were highly familiar with the discrimination task did not show consistent categorical facilitation in the other five categories. This trained group had much faster response times than the inexperienced group without any speed-accuracy trade-off. Additional analyses suggest that categorical facilitation occurs when observers pay attention to the categorical distinction but not when they respond automatically based on sensory feed-forward information.

Posterior Probability Matching and Human Perceptual Decision Making.

Probability matching is a classic theory of decision making that was first developed in models of cognition. Posterior probability matching, a variant in which observers match their response probabilities to the posterior probability of each response being correct, is being used increasingly often in models of perception. However, little is known about whether posterior probability matching is consistent with the vast literature on vision and hearing that has developed within signal detection theory. Here we test posterior probability matching models using two tools from detection theory. First, we examine the models’ performance in a two-pass experiment, where each block of trials is presented twice, and we measure the proportion of times that the model gives the same response twice to repeated stimuli. We show that at low performance levels, posterior probability matching models give highly inconsistent responses across repeated presentations of identical trials. We find that practised human observers are more consistent across repeated trials than these models predict, and we find some evidence that less practised observers more consistent as well. Second, we compare the performance of posterior probability matching models on a discrimination task to the performance of a theoretical ideal observer that achieves the best possible performance. We find that posterior probability matching is very inefficient at low-to-moderate performance levels, and that human observers can be more efficient than is ever possible according to posterior probability matching models. These findings support classic signal detection models, and rule out a broad class of posterior probability matching models for expert performance on perceptual tasks that range in complexity from contrast discrimination to symmetry detection. However, our findings leave open the possibility that inexperienced observers may show posterior probability matching behaviour, and our methods provide new tools for testing for such a strategy.

Validation of a new t2* algorithm and its uncertainty value for cardiac and liver iron load determination from MRI magnitude images

PurposeTo validate an automatic algorithm for offline T2* measurements, providing robust, vendor‐independent T2*, and uncertainty estimates for iron load quantification in the heart and liver using clinically available imaging sequences.MethodsA T2* region of interest (ROI)‐based algorithm was developed for robustness in an offline setting. Phantom imaging was performed on a 1.5 Tesla system, with clinically available multiecho gradient‐recalled‐echo (GRE) sequences for cardiac and liver imaging. A T2* single‐echo GRE sequence was used as reference. Simulations were performed to assess accuracy and precision from 2000 measurements. Inter‐ and intraobserver variability was obtained in a patient study (n = 23).ResultsSimulations: Accuracy, in terms of the mean differences between the proposed method and true T2* ranged from 0–0.73 ms. Precision, in terms of confidence intervals of repeated measurements, was 0.06–4.74 ms showing agreement between the proposed uncertainty estimate and simulations. Phantom study: Bias and variability were 0.26 ± 4.23 ms (cardiac sequence) and −0.23 ± 1.69 ms (liver sequence). Patient study: Intraobserver variability was similar for experienced and inexperienced observers (0.03 ± 1.44 ms versus 0.16 ± 2.33 ms). Interobserver variability was 1.0 ± 3.77 ms for the heart and −0.52 ± 2.75 ms for the liver.ConclusionThe proposed algorithm was shown to provide robust T2* measurements and uncertainty estimates over the range of clinically relevant T2* values. Magn Reson Med, 2015. © 2015 The Authors. Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. Magn Reson Med 75:1717–1729, 2016. © 2015 The Authors. Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance.

Myocardial feature tracking reduces observer-dependence in low-dose dobutamine stress cardiovascular magnetic resonance.

ObjectivesTo determine whether quantitative wall motion assessment by CMR myocardial feature tracking (CMR-FT) would reduce the impact of observer experience as compared to visual analysis in patients with ischemic cardiomyopathy (ICM).Methods15 consecutive patients with ICM referred for assessment of hibernating myocardium were studied at 3 Tesla using SSFP cine images at rest and during low dose dobutamine stress (5 and 10 μg/kg/min of dobutamine). Conventional visual, qualitative analysis was performed independently and blinded by an experienced and an inexperienced reader, followed by post-processing of the same images by CMR-FT to quantify subendocardial and subepicardial circumferential (Eccendo and Eccepi) and radial (Err) strain. Receiver operator characteristics (ROC) were assessed for each strain parameter and operator to detect the presence of inotropic reserve as visually defined by the experienced observer.Results141 segments with wall motion abnormalities at rest were eligible for the analysis. Visual scoring of wall motion at rest and during dobutamine was significantly different between the experienced and the inexperienced observer (p<0.001). All strain values (Eccendo, Eccepi and Err) derived during dobutamine stress (5 and 10 μg/kg/min) showed similar diagnostic accuracy for the detection of contractile reserve for both operators with no differences in ROC (p>0.05). Eccendo was the most accurate (AUC of 0.76, 10 μg/kg/min of dobutamine) parameter. Diagnostic accuracy was worse for resting strain with differences between operators for Eccendo and Eccepi (p<0.05) but not Err (p>0.05).ConclusionWhilst visual analysis remains highly dependent on operator experience, quantitative CMR-FT analysis of myocardial wall mechanics during DS-CMR provides diagnostic accuracy for the detection of inotropic reserve regardless of operator experience and hence may improve diagnostic robustness of low-dose DS-CMR in clinical practice.

A new validated T2* analysis method with certainty estimates for cardiac and liver iron load determination

Background Accurate quantification of iron load is of importance in tailoring the therapy for patients with iron load disease. Magnetic resonance (MR) imaging is commonly used to assess iron load in different organs by calculating the T2* value. Estimation of precision and uncertainty of the obtained T2* value may be useful for determining changes in iron load between follow-up scans and for titration of treatment. Therefore, the purpose of this study was to develop and validate a new T2* analysis method, providing certainty estimates for quantification of iron load in heart and liver. Methods The proposed method is ar egion of interest (ROI)based algorithm which changes curve-fitting procedure based on the results from an initial T2* estimate using a 3-parameter, noise-corrected model. The certainty estimate, presented as the T2* value confidence interval, is derived from multiple sub-regions within the selected ROI. Except for ROI delineation, the proposed method does not require any user interaction. Phantom imaging was performed on a 1.5T system, with two clinically available multi-echo gradient-recalled echo sequences for cardiac and liver imaging. Phantoms were constructed to cover the clinically important range of T2*. A T2* single-echo gradient-echo sequence with TR set to 6 × T1 and a 50° flip angle was used as reference standard. Computer simulations were performed to assess accuracy and precision from 2 000 repetitions at SNR=15. Inter- and intra-observer variability was obtained in patients (n=22) by one experienced and one inexperienced observer.

Relationship between behavior and cardiac response to round pen training

The aim of this study was to assess the correlation between heart rate (HR) and heart rate variability (HRV) and the most expressive behaviors of horses during pretraining, based on the natural horsemanship method. The study involved 20 Arabian stallions and 20 thoroughbred stallions. The horses had not been previously trained. The study covered a 3-day training cycle aimed at horse acceptance of the rider. The training lasted for 15 minutes each day (three 5-minute intervals). HR and HRV parameters (root mean square of successive beat-to-beat differences, low frequency, high frequency, and low frequency/high frequency) were used as physiological indicators of stress. At the same time, 3 inexperienced observers noted the behavioral reactions of the horses. Further analysis involved only those behavioral reactions that were spotted by all the observers at the same time. These behavioral reactions were defecation, vocalization, high head position, oral behavior, and escape attempt. It was found that the assessment of horse behavior, based on the behavioral responses of the horses while using the natural horsemanship method of training, was not accurate. This was evidenced by the small number of significant correlations between the frequency of behavioral reactions and the HR and HRV parameters in thoroughbreds and the lack of correlation in Arabian horses. Escape attempt and frequency of vocalization should be considered as the most important behavioral responses in the assessment of thoroughbred horses. It is also important to carry out a proper assessment of the emotional reaction in the first 10 minutes of training, which are the most stressful.

A Novel Device to Exploit the Smartphone Camera for Fundus Photography.

Purpose. To construct an inexpensive, convenient, and portable attachment for smartphones for the acquisition of still and live retinal images. Methods. A small optical device based on the principle of direct ophthalmoscopy was designed to be magnetically attached to a smartphone. Representative images of normal and pathological fundi were taken with the device. Results. A field-of-view up to ~20° was captured at a clinical resolution for each fundus image. The cross-polarization technique adopted in the optical design dramatically diminished corneal Purkinje reflections, making it possible to screen patients even through undilated pupils. Light emission proved to be well within safety limits. Conclusions. This optical attachment is a promising, inexpensive, and valuable alternative to the direct ophthalmoscope, potentially eliminating problems of poor exam skills and inexperienced observer bias. Its portability, together with the wireless connectivity of smartphones, presents a promising platform for screening and telemedicine in nonhospital settings. Translational Relevance. Smartphones have the potential to acquire retinal imaging for a portable ophthalmoscopy.

Cervix assessment for the management of labor induction: reliability of cervical length and Bishop score determined by residents.

To evaluate the reliability of two techniques of cervical ripeness assessment at the beginning of labor induction, as assessed by inexperienced observers. A total of 120 women were prospectively studied at admission for labor induction. Two independent physicians examined consenting women successively but separately. One experienced consultant and one of the six first-year obstetrics residents composed the pairs of observers. The trainees had very limited prior experience with cervical ultrasound scan or evaluating Bishop score. Cervical length and Bishop score were evaluated according to standard methodology. Reliability was described by intraclass correlation coefficients (ICC) and coefficients of variation (COV). Ultrasound cervical length was plotted according to the Bland-Altman method. The median Bishop score and mean cervical length were similar for all observers. Ultrasound cervical length and Bishop score were highly reliable when evaluated by first-year residents. Ultrasound cervical length showed the highest interobserver agreement, with ICC values over 0.9 and COV values of approximately 10% or less for all trainees. The Bishop score was also reliable, but with lower ICC and higher COV values. Bishop score and ultrasound cervical length examination for the management of labor induction are accurate and easy to learn by inexperienced first-year residents. However, cervical length showed higher reliability than the Bishop score.

Measuring echogenicity and area of the puborectalis muscle: method and reliability.

To develop a semi-automated method to assess puborectalis muscle echogenicity on three-dimensional/four-dimensional (3D/4D) volume transperineal ultrasound images using 4D View and Matlab® software and evaluate its intra- and interobserver reliability. The data of 23 women in their first trimester were included. 3D/4D volume datasets were obtained at rest. Two inexperienced observers were trained by an experienced observer to construct tomographic ultrasound images (TUI) from the original data and to delineate all structures. Puborectalis muscle area (PMA) and the mean echogenicity of the puborectalis muscle (MEP) were calculated offline. Intra- and interobserver reliability were determined by intraclass correlation coefficients (ICC) and their 95% CIs. The development of a semi-automated method to calculate puborectalis area and echogenicity is described in detail. PMA and MEP measurements in pregnant women demonstrated almost perfect intraobserver reliability for both inexperienced observers, with ICC values ranging from 0.88 to 0.99. The interobserver reliability showed ICCs of 0.63 for PMA and almost perfect ICC values, of 0.96-0.98, for echogenicity. The majority of intraobserver mismatch between two delineations of PMA occurred near the borders. Matlab software can be used to provide reliable measurements of the area and echogenicity of the puborectalis muscle. As the latter can be used to assess structural changes in the puborectalis muscle, it appears a promising new tool for studying pelvic floor structural anatomy.

Learning curve and interobserver agreement of confocal laser endomicroscopy for detecting precancerous or early-stage esophageal squamous cancer.

BackgroundConfocal laser endomicroscopy (CLE) can provide in vivo subcellular resolution images of esophageal lesions. However, the learning curve in interpreting CLE images of precancerous or early-stage esophageal squamous cancer is unknown. The goal of this study is to evaluate the diagnostic accuracy and inter-observer agreement for differentiating esophageal lesions in CLE images among experienced and inexperienced observers and to assess the learning curve.MethodAfter a short training, 8 experienced and 14 inexperienced endoscopists evaluated in sequence 4 sets of high-quality CLE images. Their diagnoses were corrected and discussed after each set. For each image, the diagnostic results, confidence in diagnosis, quality and time to evaluate were recorded.ResultsOverall, diagnostic accuracy was greater for the second, third, fourth set of images as compared with the initial set (odds ratio [OR] 2.01, 95% CI 1.22–3.31; 7.95, 3.74–16.87; and 6.45, 3.14–13.27), respectively, with no difference between the third and fourth sets in accuracy (p = 0.67). Previous experience affected the diagnostic accuracy only in the first set of images (OR 3.70, 1.87–7.29, p<0.001). Inter-observer agreement was higher for experienced than inexperienced endoscopists (0.732 vs. 0.666, p<0.01)ConclusionCLE is a promising technology that can be quickly learned after a short training period; previous experience is associated with diagnostic accuracy only at the initial stage of learning.

Can an inexperienced observer accurately plot disc contours using Heidelberg retinal Tomograph?

ObjectiveTo examine the reliability of inexperienced observers in plotting optic disc contours on Heidelberg retinal tomography images before and after training. DesignObservational study. ParticipantsOne hundred eyes that were randomly selected from the Singapore Indian Eye Study. MethodsBoth eyes of subjects were imaged with Heidelberg Retina Tomograph 3 (HRT-3; Heidelberg Engineering, Heidelberg, Germany). Optic disc contours were plotted on the same images by 2 new observers on 2 separate occasions, before and after 2-hour standardized training on the skills and tools available to accurately identify and delineate optic disc contours. These plottings were compared with an experienced, trained glaucoma expert (gold standard). Agreement and variability were analyzed by interclass correlation tests and Bland–Altman plots. ResultsA total of 182 images (18 excluded because of poor quality) from 89 Indian subjects were included. The mean age was 53.27 ± 7.25 years and 54.8% were male. There was moderate-to-high agreement between pretraining (both new observers) and experienced observer’s results (interclass correlation values range, 0.76–0.99). The interclass correlation improved for all the HRT-3 parameters after the 2 new observers were adequately trained. Comparing the interclass correlation values before and after training, the differences for mean retinal nerve fibre layer thickness for Observer 1 and all the HRT-3 parameters for Observer 2 were statistically significant. ConclusionsThis study shows that it is easy to train a new inexperienced observer to plot optic disc contours on HRT images, which translates into improved and acceptable interobserver variability and agreement.

Accuracy of Visual Scoring and Semi-Quantification of Ultrasound Strain Elastography – A Phantom Study

PurposeThe aim of this study was to evaluate the performance of strain elastography in an elasticity phantom and to assess which factors influenced visual scoring, strain histograms and strain ratios. Furthermore this study aimed to evaluate the effect of observer experience on visual scorings.Materials and MethodsTwo operators examined 20 targets of various stiffness and size (16.7 to 2.5 mm) in an elasticity phantom at a depth of 3.5 cm with a 5–18 MHz transducer. Two pre-settings were used yielding 80 scans. Eight evaluators, four experienced, four inexperienced, performed visual scorings. Cut-offs for semi-quantitative methods were established for prediction of target stiffness. Data was pooled in two categories allowing calculations of sensitivity and specificity. Statistical tests chi-square test and linear regression as relevant.ResultsStrain ratios and strain histograms were superior to visual scorings of both experienced and inexperienced observers (p = 0.025, strain histograms vs. experienced observers, p<0.001, strain histograms vs. inexperienced observers, p = 0.044 strain ratios vs. experienced observers and p = 0.002 strain ratios vs. inexperienced observers). No significant difference in predicting target stiffness between strain ratios and strain histograms (p = 0.83) nor between experienced and inexperienced observers (p = 0.054) was shown when using four categories. When pooling data in two groups (80 kPa/45 kPa vs. 14/8 kPa) the difference between the observers became significant (p<0.001). Target size had a significant influence on strain ratios measurements (p = 0.017) and on visual scorings (p<0.001) but not on the strain histograms(p = 0.358). Observer experience had significant effect on visual scorings(p = 0.003).ConclusionStrain ratios and strain histograms are superior to visual scoring in assessing target stiffness in a phantom. Target size had a significant impact on strain ratios and visual scoring, but not on strain histograms. Experience influenced visual scorings but the difference between experienced and inexperienced observers was only significant when looking at two classes of target stiffness.

Incidental findings on cone beam computed tomographic images: a Pandora's box?

Incidental findings on cone beam computed tomographic images: a Pandora's box?

Monitoring Whooping Crane Abundance Using Aerial Surveys: Influences on Detectability.

The whooping crane (Grus americana), an endangered species, has been counted on its winter grounds in Texas, USA, since 1950 using fixed-wing aircraft. Many shortcomings of the traditional survey technique have been identified, calling into question its efficacy, defensibility, repeatability, and usefulness into the future. To improve and standardize monitoring effort, we began investigating new survey techniques. Here we focus on efficacy of line transect-based distance sampling during aerial surveys. We conducted a preliminary test of distance sampling during winter 2010–2011 while flying the traditional survey, which indicated that detectability within 500 m of transects was 0.558 (SE = 0.031). We then used an experimental decoy survey to evaluate impacts of observer experience, sun position, distance from transect, and group size on detectability. Our results indicated decoy detectability increased with group size and exhibited a quadratic relationship with distance likely due to pontoons on the aircraft. We found that detectability was 2.704 times greater when the sun was overhead and 3.912 times greater when the sun was at the observer's back than when it was in the observer's eyes. We found that an inexperienced observer misclassified non-target objects more often than an experienced observer. During the decoy experiment we used marks on the struts to categorize distances into intervals, but we found that observers misclassified distances 46.7% of the time (95% CI = 37.0–56.6%). Also, we found that detectability of individuals within detected groups was affected by group size and distance from transect. We discuss how these results inform design and implementation of future whooping crane monitoring efforts. Published 2013. This article is a U.S. Government work and is in the public domain in the USA.

Comparison of the “Real-life” Diagnostic Value of Two Recently Published Electrocardiogram Methods for the Differential Diagnosis of Wide QRS Complex Tachycardias

The diagnostic values of the aVR lead or "Vereckei algorithm," and the lead II R-wave peak time (RWPT) criterion, recently devised for the differential diagnosis of wide QRS complex tachycardias (WCTs), were compared. A total of 212 WCTs (142 ventricular tachycardias [VTs], 62 supraventricular tachycardias [SVT], and eight preexcitation SVTs) from 145 patients with proven electrophysiologic diagnoses were retrospectively analyzed by seven examiners blinded to the electrophysiologic diagnoses. The overall test accuracy of the Vereckei algorithm was superior to that of the RWPT criterion (84.3% vs. 79.6%; p = 0.0003). The sensitivity of the Vereckei algorithm for VT diagnosis was greater than that of RWPT criterion (92.4% vs. 79.1%; p < 0.0001). The negative predictive value (NPV) for the Vereckei algorithm was also greater (77.8%; 95% confidence interval [CI] = 73.6% to 82.1%) than that of the RWPT criterion (61.6%; 95% CI = 57.6% to 65.6%). The specificity of the Vereckei algorithm was lower than that of the RWPT criterion (64.7% vs. 80.9%; p < 0.0001). The positive predictive value (PPV) was also lower for the Vereckei algorithm (86.4%; 95% CI = 84.4% to 88.4%) than for the RWPT criterion (90.9%; 95% CI = 89.1% to 92.8%). Incorrect diagnoses made by the Vereckei algorithm were mainly due to misdiagnosis of SVT as VT (65.7% of cases), and those made by the RWPT criterion were due to the more dangerous misdiagnosis of VT as SVT (72.5% of cases). The Vereckei algorithm was superior in overall test accuracy, sensitivity, and NPV for VT diagnosis and inferior in specificity and PPV to the RWPT criterion. All of these parameters were lower in "real life" than those reported by the original authors for each of the particular electrocardiographic methods.

Reliability of pelvic floor measurements on three- and four-dimensional ultrasound during and after first pregnancy: implications for training

To evaluate the reliability of measurements of the levator hiatus and levator-urethra gap (LUG) using three/four-dimensional (3D/4D) transperineal ultrasound in women during their first pregnancy and 6 months postpartum, and to assess the learning process for these measurements. An inexperienced observer was taught to perform measurements of the levator hiatus and LUG by an experienced observer. After training, 3D/4D ultrasound volume datasets of 40 women in the first trimester were analyzed by these two observers. Another training session then took place and both observers repeated the analyses of the same volume datasets. Finally, analyses of 40 volume datasets of the women 6 months postpartum were performed by both observers. Intra- and interobserver reliability were determined by intraclass correlation coefficients (ICC) with 95% CIs. For levator hiatal measurements, in the women during their first pregnancy the interobserver reliability was substantial to almost perfect after both the first and second training session (ICC, 0.62-0.83 and 0.71-0.89, respectively, for anteroposterior diameter, transverse diameter and area at rest, on contraction and on Valsalva) and the intraobserver reliability was substantial to almost perfect for both observers. For these measurements performed once the women had delivered, interobserver reliability was moderate to almost perfect. For LUG measurements performed during pregnancy, interobserver reliability was slight to moderate after the first training session (ICC, 0.14-0.54), but improved after the second training session (ICC, 0.38-0.71), and intraobserver reliability was moderate to substantial for the experienced observer and slight to moderate for the inexperienced observer. For these measurements performed when the women had delivered, interobserver reliability was fair to moderate. The levator hiatus and LUG can be measured reliably using 3D/4D ultrasound in primigravid and primiparous women. The technique to measure dimensions of the levator hiatus requires limited teaching, but LUG measurements are more difficult and require more extensive training.