Intraobserver Differences Research Articles

Analysis of Measurement Accuracy for Craniovertebral Junction Pathology : Most Reliable Method for Cephalometric Analysis

ObjectiveThis study was designed to determine the most reliable cephalometric measurement technique in the normal population and patients with basilar invagination (BI).MethodsTwenty-two lateral radiographs of BI patients and 25 lateral cervical radiographs of the age, sex-matched normal population were selected and measured on two separate occasions by three spine surgeons using six different measurements. Statistical analysis including intraclass correlation coefficient (ICC) was carried out using the SPSS software (V. 12.0).ResultsRedlund-Johnell and Modified (M)-Ranawat had a highest ICC score in both the normal and BI groups in the inter-observer study. The M-Ranawat method (0.83) had a highest ICC score in the normal group, and the Redlund-Johenll method (0.80) had a highest ICC score in the BI group in the intra-observer test. The McGregor line had a lowest ICC score and a poor ICC grade in both groups in the intra-observer study. Generally, the measurement method using the odontoid process did not produce consistent results due to inter and intra-observer differences in determining the position of the odontoid tip. Opisthion and caudal point of the occipital midline curve are somewhat ambiguous landmarks, which induce variable ICC scores.ConclusionOn the contrary to other studies, Ranawat method had a lower ICC score in the inter-observer study. C2 end-plate and C1 arch can be the most reliable anatomical landmarks.

Reproducibility of computed tomography angiography data analysis using semiautomated plaque quantification software: implications for the design of longitudinal studies

Reproducibility of the quantitative assessment of atherosclerosis by computed tomography coronary angiography (CTCA) is paramount for the design of longitudinal studies. The purpose of this study was to assess the inter- and intra-observer reproducibility using semiautomated CT plaque analysis software in symptomatic individuals. CTCA was performed in 10 symptomatic patients after percutaneous treatment of the culprit lesions and was repeated after 3 years. The plaque quantitative analysis was performed in untreated vessels with mild-to-moderate atherosclerosis and included geometrical and compositional characteristics using semiautomated CT plaque analysis software. A total of 945 matched cross-sections from 21 segments were analyzed independently by a second reviewer to assess inter-observer variability; the first observer repeated all the analyses after 3 months to assess intra-observer variability. The observer variability was also compared to the absolute plaque changes detected over time. Agreement was evaluated by Bland-Altman analysis and concordance correlation coefficient. Inter-observer relative differences for lumen, vessel, plaque area and plaque burden were 1.2, 0.6, 2.2, 1.6% respectively. Intra-observer relative differences for lumen, vessel, plaque area and plaque burden were 1.0, 0.4, 0.2, 0.4% respectively. For the average plaque attenuation values the inter- and intra-observer variability was 5 and 2% respectively. For the % low-attenuation-plaque the inter- and intra-observer variability was 16 and 6% respectively. The absolute intra-observer variability for the plaque burden was 1.30 ± 1.09%, while the temporal plaque burden difference was 3.55 ± 3.02 % (p = 0.001). The present study shows that the geometrical assessment of coronary atherosclerosis by CTCA is highly reproducible within and between observers using semiautomated quantification software and that serial plaque changes can be detected beyond observer variability. The compositional measurements are more variable between observers than geometrical measurements.

Predicting neurodevelopmental outcomes for at-risk infants: reliability and predictive validity using a Chinese version of the INFANIB at 3, 7 and 10 months

BackgroundChinese primary care settings have a heavy patient load, shortage of physicians, limited medical resources and low medical literacy, making it difficult to screen for developmental disorders in infants. The Infant Neurological International Battery (INFANIB) for the assessment of neuromotor developmental disorders in infants aged 0 ~ 18 months is widely applied in community health service centers because of its simplicity, time-saving advantages and short learning curve. We aimed to develop and assess a Chinese version of the INFANIB.MethodsA Chinese version of the INFANIB was developed. Fifty-five preterm and 49 full-term infants with high risk of neurodevelopmental delays were assessed using the Chinese version of the INFANIB at 3, 7 and 10 months after birth. The Peabody Developmental Motor Scale (PDMS) was simultaneously used to assess the children with abnormalities and diagnose cerebral palsy. The sensitivity, specificity, positive predictive value and negative predictive value of the scale were calculated.ResultsAt birth, a higher proportion of full-term infants had asphyxia (p < 0.001), brain damage ( p = 0.003) and hyperbilirubinemia ( p = 0.022). The interclass correlation coefficient and intraclass correlation coefficient values for the INFANIB at 3, 7 and 10 months were >0.8, indicating excellent reliability with regard to inter- and intraobserver differences. The specificity, sensitivity, positive predictive value and negative predictive value were high for both high-risk premature infants and full-term infants at the age of 10 months. For premature infants at the age of 7 months or below, INFANIB had low validity for detecting abnormalities.ConclusionsThe Chinese version of the INFANIB can be useful for screening infants with high-risk for neuromotor abnormality in Chinese primary care settings.

Reliability Analysis of a Smartphone-aided Measurement Method for the Cobb Angle of Scoliosis

A comparison between the smartphone-aided measurement method and the manual measurement method for the Cobb angle in adolescent idiopathic scoliosis. To evaluate the reliability and measurement error for the smartphone-aided Cobb angle measurement method and compare its reliability and measurement error with those of the manual method. The development of smartphones has provided new opportunities that integrate mobile technology into daily clinical practice. Smartphone applications can provide quick assistance in the diagnosis and treatment of disease. Cobbmeter is a smartphone application designed for the measurement of Cobb angle on Apple iPhone smartphones. There is no study on the reliability and measurement error of this smartphone-aided measurement method. : Fifty-three posteroanterior radiographs of adolescent idiopathic scoliosis patients with thoracic scoliosis were used for the standard Cobb method of measurement (manual set) and the smartphone-aided Cobb method of measurement (smartphone set). Five spinal surgeons measured the Cobb angle with the use of both the manual method and the smartphone-aided method. The measurement time was recorded for every measurement. The frequency and the cumulative percent distribution for intraobserver differences were tabulated, both for the individual examiners and for the overall results for the 5 examiners. The intraclass correlation coefficient (ICC) 2-way mixed model on absolute agreement was used to analyze measurement reliability. Summary statistics from analyses of variance calculations were used to provide 95% prediction limits for the error in measurements. A paired t test was used to compare the time consumed for the measurement between both sets. The intraobserver and interobserver ICCs were excellent in the smartphone set and in the manual set. Both the intraobserver ICC and the interobserver ICC were better in the smartphone set than in the manual set. The mean Cobb angle of all measured x-rays was 29.3 degrees (range, 17-58 degrees) in the manual set and 29.1 degrees (range, 18-56 degrees) in the smartphone set. The mean time consumed was 13.7 seconds (range, 8.6-18.5 s) for the smartphone set, whereas it was 37.9 seconds (range, 30.1-46.9 s) for the manual set, and the mean time consumed for the smartphone set was significantly shorter than that of the manual set (P<0.05). Smartphone-aided measurement for Cobb angle showed excellent reliability and efficiency. It is suggested to popularize the use of this method in clinical practice.

005 Cardiac MRI: understanding myocardial motion to predict remodelling pre cardiac resynchronisation therapy

IntroductionA significant number of patients undergoing Cardiac Resynchronisation Therapy (CRT) do not remodel. Assessing global dyssynchrony has the potential to improve patient selection. We developed a framework for comparing measures...

Intra‐ and interobserver variability in fetal ultrasound measurements

To assess intra- and interobserver variability of fetal biometry measurements throughout pregnancy. A total of 175 scans (of 140 fetuses) were prospectively performed at 14-41 weeks of gestation ensuring an even distribution throughout gestation. From among three experienced sonographers, a pair of observers independently acquired a duplicate set of seven standard measurements for each fetus. Differences between and within observers were expressed in measurement units (mm), as a percentage of fetal dimensions and as gestational age-specific Z-scores. For all comparisons, Bland-Altman plots were used to quantify limits of agreement. When using measurement units (mm) to express differences, both intra- and interobserver variability increased with gestational age. However, when measurement of variability took into account the increasing fetal size and was expressed as a percentage or Z-score, it remained constant throughout gestation. When expressed as a percentage or Z-score, the 95% limits of agreement for intraobserver difference for head circumference (HC) were ± 3.0% or 0.67; they were ± 5.3% or 0.90 and ± 6.6% or 0.94 for abdominal circumference (AC) and femur length (FL), respectively. The corresponding values for interobserver differences were ± 4.9% or 0.99 for HC, ± 8.8% or 1.35 for AC and ± 11.1% or 1.43 for FL. Although intra- and interobserver variability increases with advancing gestation when expressed in millimeters, both are constant as a percentage of the fetal dimensions or when reported as a Z-score. Thus, measurement variability should be considered when interpreting fetal growth rates.

Evaluation of Dosimetric Consequences of Seroma Contour Variability in Accelerated Partial Breast Irradiation Using a Constructed Representative Seroma Contour

Contouring variability of the seroma can have important implications in the planning and delivery of accelerated partial breast irradiation (APBI). This study aimed to quantify the dosimetric impact of these interobserver and intraobserver contouring variations by construction of a representative seroma contour (RSC). Twenty-one patients with a seroma suitable for APBI underwent four computed tomography (CT) scans: one planning CT and three additional CTs on the first, third, and fifth days of treatment. Three radiation oncologists contoured the seroma on each CT scan. For 3 patients, oncologists repeated contouring twice to assess intraobserver variations. Seroma contour variability was quantified by construction of an RSC. In addition, the percent volume overlap (PVO) was calculated. Root-mean-square (RMS) differences in seroma volume, size, and center of mass position compared to those of the RSC were calculated. Treatment fields from the original plan were applied to the repeated CTs by using the same isocenter shifts as the original plan. The dosimetric impact of the contour variations was assessed using V(95) (volume receiving at least 95% of the prescribed dose) and equivalent uniform dose (EUD). Interobserver RMS volume differences were, on average, 5.6 times larger than intraobserver differences. The median interobserver RMS seroma volume difference was 1.48 cm(3). The median PVO was 51.6%. V(95) and EUD of the seroma contours were similar for all patients. Themedian RMS differences of the seroma V(95) and EUD were 0.01% (range, 0%-3.99%) and 0.05 Gy (range, 0-0.98 Gy). Construction of the RSC showed that interobserver variations were most responsible for contour variations of the seroma. Current planning margins provided adequate dose coverage of the seroma despite these contour variations.

Clinical significance of lymph vessel density in T3 colorectal carcinoma

The purpose of the present study is to characterise the lymphatic vessel density (LVD) in the T3 colorectal carcinoma and to correlate it with N status, grading and presence of tumour budding. A total of 56 cases of T3 colorectal carcinoma were retrieved from the pathology's archive of Klinikum Augsburg. All slides were stained immunohistochemically with D2-40 (lymphatic endothelium) and with pancytokeratin to assess the tumour budding. Tumour budding and lymph vessel density were investigated independently by BM and CC. The highest density of lymphatic vessels was counted both in tumour centre (ILVD) and at the periphery of the tumour (PLVD) within an area of 0.24mm(2). Due to the strong intra-observer (BM and CC) difference in ILVD and PLVD, all cases were re-evaluated establishing a consensus that has been used for the further analyses. There was a significant difference between PLVD and ILVD (12 ± 4 versus 6 ± 3; P < 0.001). Moreover, we found a non-significant trend towards high PLVD in the cases with nodal metastasis versus the negative one, 13 ± 5/hpf versus 11 ± 4 (P = 0.072). There was no association between tumour budding and ILVD and PLVD (P = 0.249 and 0.38). Colorectal carcinoma induces lymphangiogenesis. A higher PLVD could increase the capability of cancer cell to invade the lymphatic system. However, the obvious difficulties in immunohistochemical evaluation and the rather small differences between nodal positive and negative cases in T3 colorectal cancer seem to limit the clinical value of LVD evaluation.

Radiographic landmarks for measurement of cranial tibial subluxation in the canine cruciate ligament deficient stifle

The primary objective was to develop a repeatable radiographic technique for assessment of cranial tibial subluxation (CTS) and test the intra-observer and inter-observer repeatability of the chosen landmarks. A secondary objective was to determine the effects of digital radiographic magnification on CTS measurement repeatability. Twenty-three normal canine pelvic limbs were used to determine the magnitude of CTS before and after transection of the cranial cruciate ligament. Mediolateral radiographs were taken with and without fiduciary markers in place. Three investigators measured the CTS using radiographically visible anatomic landmarks at two different magnifications. The total observed variabilities were assessed by inter-observer and intra-observer differences. Paired t-tests were used to determine the effect of magnification and marker presence on CTS measures. Measurement of the CTS from the caudal margin of the intercondylar fossa on the femur to the intercondylar eminence was the most repeatable. Poor correlation between the anatomic landmarks and the fiduciary bone markers was observed. We found no effect of magnification or presence or absence of bone markers on measurement of CTS. Cranial tibial subluxation can be detected with the most repeatability by measuring between the caudal margin of the intercondylar fossa and the intercondylar eminence. Magnification of the digitized radiographic image had minimal effect on repeatability. This technique can be used for in vivo analysis of the canine cruciate ligament deficient stifle joint.

ビデオ観察法を用いて咀嚼行動を観察する際の観察者間および観察者内誤差の検討

The present study aimed to investigate inter- and intraobserver error in order to clarify whether mastication time and frequency can be accurately measured using video observation. Mastication time and frequency were measured from video camera footage of four subjects. Interobserver error was calculated based on differences in measurement values between two observers′ single observations of the four subjects and analyzed using intraclass correlation coefficient. Intraobserver error was calculated based on differences in measurement values from one observer′s observations of the four subjects repeated three times and analyzed using one-way analysis of variance and intraclass correlation coefficient. Intraclass correlation coefficient was ≥0. 9 for both inter- and intraobserver measurements of mastication time and frequency, demonstrating small inter- and intraobserver error. No significant differences in mean values were observed for intraobserver error with one-way analysis of variance. The present findings indicate that inter- and intraobserver differences in measurement values for mastication time and frequency based on video observation are small, suggesting that one measurement by one observer is likely to provide representative values for mastication time and frequency during video observation.

The Sensory Field and Repeatability of the Cutaneous Trunci Muscle Reflex of the Dog

To describe the cutaneous trunci muscle (CTM) reflex in dogs. Prospective descriptive study. Normal dogs (n = 155) and 10 dogs with thoracolumbar myelopathies. The CTM reflex caudal border was assessed from the ilial crests moving cranially until a CTM contraction was elicited. The lateral borders were evaluated at 4 levels and the distance from the midline to the lateral border was expressed asa percentage of the trunk hemicircumference. The caudal border was assessed in 10 dogs with myelopathies by 4 different observers and by 1 observer on 3 occasions;the inter- and intraobserver kappa coefficient was calculated. The CTM reflex was elicited in all dogs. Its caudal border was at L5 or L6 in 153 dogs and at L1 and L3 in 2 dogs. The lateral field of the reflex occupied>50%of the hemicircumference of the trunk at each level tested. The mean difference in measurement of the reflex caudal border was 0.55 cm between observers and 0.28 cm for the same observer. The inter- and intraobserver kappa coefficient was 0.67 and 0.87, respectively. The CTM reflex is elicited caudal to L5 in most normal dogs, and the lateral sensory field extends to 50% or more of the circumference of the trunk.Inter- and intraobserver differences in assessment of the caudal border are low.

Evaluation of oral mucosal diseases: inter‐ and intra‐observer analyses

Essential to the diagnosis and management of oral mucosal diseases are visual evaluation and monitoring of the oral cavity. Digital photography has recently become an important clinical tool. The aims of this study were to (i) evaluate inter- and intra-observer differences between oral medicine and other dental specialists when assessing changes in oral mucosal pathology and (ii) assess the influence of calibration labels incorporated into the clinical images on the reliability and consistency of evaluation. Ten oral medicine specialists (OM) and 10 other dental specialists (DS) participated in the study. Pairs of images captured with an intraoral camera at two time points from 17 cases of mucosal diseases were presented to the participants. Each pair of photographs was presented with a calibration label (showing length and white to black hues) and again without one. The participants were asked to respond to a questionnaire evaluating changes in size, color, location, and severity for each image pair. Oral medicine specialists had better absolute agreement and consistency than DS when evaluating the changes in the images; however, these parameters did not exceed 52% in either group. The incorporation of a calibration label in the images increased agreement and consistency of evaluations in both groups. Follow-up evaluations of oral mucosal lesions are performed better by oral medicine practitioners compared to other dental specialists. The incorporation of a calibration label in the clinical images seems to enhance evaluation.

Repeatability and Reproducibility of Quantitative Whole-lung Perfusion Magnetic Resonance Imaging

Magnetic resonance imaging (MRI) allows for quantitative evaluation of pulmonary perfusion and has shown high clinical usefulness for the evaluation and differentiation of different lung pathologies. The reproducibility of quantitative analysis of whole-lung perfusion has not been investigated previously. Our aim was to assess the intraobserver and interobserver repeatability and reproducibility of perfusion MRI to prove the concept that perfusion is suitable for therapy monitoring. The study was approved by the International Review Board. Fourteen healthy volunteers were examined using a time-resolved FLASH 3-dimensional perfusion sequence (1.5-T MRI, TREAT, GRAPPA 2, coronal orientation, voxel size 3.9×3.9×6.3 mm(3)). Perfusion was assessed initially and after 24 hours during an inspiratory and an expiratory breath hold. For each examination, 0.05 mmol/kg BW of Gd-DTPA was injected. Perfusion parameters such as pulmonary blood flow (PBF), pulmonary blood volume, and mean transit time were calculated. The evaluation was performed independently by 2 blinded observers. Intraobserver and interobserver differences were determined. The intraobserver differences between the initial and follow-up examinations for pulmonary blood volume, mean transit time, and time to peak were not significantly different for observers 1 and 2. PBF showed a significant difference for both observers only on inspiration (P<0.006 for observer 1 and P<0.009 for observer 2). For interobserver evaluation, all parameters, except inspiratory PBF, were significantly different (P<0.0001). Intraobserver quantitative perfusion MRI showed reproducible results. However, the evaluation is highly dependent on the observer. Therefore, quantitative analysis of the serial examinations should be performed by the same observer.

Direct measurement of acetabular radiographic version using an ordinary goniometer – a precision study

Objective: The acetabular version following total hip arthroplasty is an important prognostic factor. Computer navigation serves as a precise tool during hip arthroplasty, which requires precise measurement to verify the effect of the procedure. Wan and colleagues have reported an innovative method for measuring acetabular radiographic version with an ordinary goniometer. Our objective was to study the precision of this method.Methods: We derived the underlying mathematical principle of Wan's method and produced a correction formula and chart. Forty-eight computer-synthesized radiographs were used to study the method and its mathematical correction. Ten real radiographs were used to detect intra-observer difference. The paired t-test was used for statistical analysis.Results: There was a significant difference between synthetic acetabular radiographic version and the measurement obtained with Wan's method (p < 0.05), but there was no difference after mathematical correction (p = 0.15). For smaller radiographic version (<20o), there was no statistical difference using Wan's method (p = 0.054).Conclusions: The method of Wan and colleagues can be used when acetabular radiographic version is less than 20°. For larger radiographic versions, however, mathematical correction is necessary to obtain precise results.

Assessment of pulmonary artery stiffness using velocity-encoding magnetic resonance imaging: evaluation of techniques

The loss of pulmonary artery (PA) compliance has significant pathophysiological effect on the right ventricle. Noninvasive and reliable assessment of PA wall stiffness would be an essential determiner of right heart load and a clinically useful factor to assess cardiovascular risk. Two MRI techniques have been proposed for assessing PA stiffness by measuring pulse wave velocity (PWV): transit time (TT) and flow area (QA). However, no data are available that compares the two techniques and evaluates their performance, especially over a wide range of PWV values or at 3.0-T, which is the purpose of the present study. Thirty-three patients with different heart conditions were imaged using optimized high-temporal resolution and high-spatial resolution velocity-encoding MRI sequences. Statistical analysis was conducted to study intermethod, interobserver and intraobserver variabilities. The PWV measurements using TT and QA techniques showed good agreement ( P>0.1). The Bland–Altman analysis showed negligible differences between the two methods (mean±S.D.=0.11±0.35 m/s, correlation coefficient r=0.94). The repeated measurements showed low interobserver and intraobserver variabilities, although the S.D. of the differences was larger in the QA technique. The mean±S.D. of the TT/QA measurement differences were −0.05±0.2/0.0±0.36 m/s and 0.02±0.26/0.02±0.39 m/s for the interobserver and intraobserver differences, respectively. In conclusion, each technique has its own advantages and disadvantages. The two techniques result in similar measurements, although the QA method is more subjective due to its dependency on operator intervention.

Use of Multispectral MRI to Monitor Aneurysm Sac Contents After Endovascular Abdominal Aortic Aneurysm Repair

To validate a newly developed semi-automatic multispectral magnetic resonance imaging (MRI) tool for quantitatively monitoring aneurysm sac contents in patients after endovascular aneurysm repair (EVAR). MRI studies from 24 EVAR patients were retrospectively analyzed. The precontrast T₁-weighted and T₂-weighted and the postcontrast T₁-weighted images were displayed simultaneously. Two independent observers classified the aneurysm sac voxels into categories for endoleak, unorganized thrombus, or organized thrombus by interactively thresholding the multispectral images relative to the signal intensity of fat. Voxel classification was visualized as a color overlay on the MR images; when the observer changed the thresholds, the color overlay was updated immediately. The volumes of the voxels in each category were calculated and expressed in milliliters. The intra- and interobserver variability for measuring the volumes of endoleak and unorganized and organized thrombus were calculated; a Bland and Altman analysis was applied to determine the mean differences and the repeatability coefficient (RC). Mean aneurysm sac volume was 78 ± 42 mL. The intraobserver mean difference for the endoleak volume was 0.5 ± 1.9 mL with an RC of 3.7 mL; the interobserver mean difference was -0.8 ± 3.6 mL (RC 7.1 mL). The intraobserver mean difference for unorganized thrombus volume was -1.2 ± 4.4 mL (RC 8.6 mL); the interobserver mean difference was 0.3 ± 6.3 mL with an RC of 12.3 mL. The intraobserver mean difference for organized thrombus volume was 0.8 ± 5.0 mL (RC 9.7 mL); the interobserver mean difference was 0.4 ± 6.3 mL (RC 12.4 mL). Reproducible monitoring of aneurysm sac contents in EVAR patients is feasible with multispectral MRI in combination with our semi-automatic post-processing tool.

Reproducibility of coronary plaque detection and characterization using low radiation dose coronary computed tomographic angiography in patients with intermediate likelihood of coronary artery disease (ReSCAN study)

The purpose of this study is to evaluate the interscan, interobserver and intraobserver agreement for coronary plaque detection, and characterization using low radiation dose high-pitch spiral acquisition coronary CT angiography (CTA). Two experienced observers independently evaluated coronary CTA datasets from 50 consecutive patients undergoing two 128-slice dual source CT scans within 12 days. Mean (±SD) estimated radiation exposure was 1.5 ± 0.2 mSv per scan. Observers recorded the presence and characterization of coronary plaques as non-calcified or calcified. A "segment involvement score" (SIS) was computed by summing the numbers of segments with any coronary plaque per patient. Reproducibility was assessed using kappa (κ) statistics, paired t test and Bland-Altman analyses. Interscan, interobserver, and intraobserver agreement (κ-values) for detection of any or calcified plaques were 83-94% (κ-values 0.57-0.85), and 67-84% (0.31-0.67) for non-calcified plaques on a patient level. No significant difference was observed in mean interscan or interobserver SIS. Mean (95% CI) intraobserver SIS difference was -0.88 (-1.25; -0.51), P < 0.001, with limits of agreement from -4.7 to 2.9. Low radiation dose high-pitch coronary CTA permits detection of any or calcified plaques with high interscan, interobserver, intraobserver agreement. However, variability for the detection of non-calcified plaque is substantial.

Inter- and intra-observer variability in contouring of the prostate gland on planning computed tomography and cone beam computed tomography

Purpose. To investigate inter-/intra-observer variability in defining the prostate by use of planning computed tomography (PCT) and cone beam CT (CBCT) with magnetic resonance image (MRI) as guidance prior to the introduction of an adaptive radiotherapy for prostate cancer. Material and methods. We reviewed PCT and firstly acquired CBCT datasets of each ten patients with prostate cancer. Three physicians independently delineated the prostate based on PCT and CBCT with MRI as guidance, allowing determination of inter-physician variability. Two physicians repeated prostate contouring three times in total to investigate intra-physician variability. We compared delineated prostate volumes in terms of the generalized conformity index (CIgen), maximum variation ratio (MVR), and center of mass (COM). Results. There were no significant inter-/intra-observer differences in the estimation of prostate volume on both PCT and CBCT. For both inter- and intra-observer variability in contouring the prostate gland, there were no significant differences in MVR between PCT and CBCT. The CIgen for inter-observer variability was 0.74 by PCT and 0.69 by CBCT. The CIgen for intra-observer variability on PCT and CBCT was 0.84 and 0.81 for observer 2 and 0.76 and 0.73 for observer 3. COM analyses showed that the greatest inter-/intra-observer variability was in the measurement of the prostate apex and base. With respect to CIgen and COM analysis for the inter-observer variability, more precise delineation of the prostate was possible on PCT than CBCT. More precise contouring in terms of both CIgen and COM was demonstrated by observer 2 than observer 3. Conclusions. Despite some ambiguity in apex and base level, there was a good consistency in delineating the gland on CBCT plus MRI-guided modification both among/within observer(s), without any significant difference from the consistency in defining the prostate on PCT. This study provides a framework for future studies of CBCT imaging of the prostate.

Reproducibility of Shin’s method for necrotic core and calcium content in atherosclerotic coronary lesions treated with bioresorbable everolimus-eluting vascular scaffolds using volumetric intravascular ultrasound radiofrequency-based analysis

Although Virtual Histology intravascular ultrasound (VH-IVUS) is increasingly used in clinical research, the reproducibility of plaque composition remains unexplored in significant coronary artery and stented lesions. The purpose of this study was to assess the reproducibility of necrotic core and calcium content in atherosclerotic coronary lesions that were treated with a bioresorbable everolimus-eluting vascular scaffold (BVS) using a new measurement method (Shin's method) by VH-IVUS. Eight patients treated with a BVS (Abbott Vascular, Santa Clara, CA, USA) were analyzed with serial VH-IVUS assessments, i.e., pre- and post-stenting, and at 6 months and 2 years follow-up. A total of 32 coronary segments were imaged to evaluate the reproducibility of volumetric VH-IVUS measurements. In Shin's method, contours are drawn around the IVUS catheter (instead of the lumen) and vessel. Overall, in the imaged coronary segment, for necrotic core and dense calcium volumes, the relative intra-observer differences were 0.30 ± 0.22, 0.19 ± 0.16% for observer 1 and 0.45 ± 0.41, 0.36 ± 0.47% for observer 2, respectively. The inter-observer relative differences of necrotic core and dense calcium volumes were 0.51 ± 0.79 and 0.56 ± 1.01%, respectively. The present study demonstrates a good reproducibility for both, intra-observer and inter-observer measurements using Shin's method. This method is suitable for the measurement of necrotic core and dense calcium using VH-IVUS in longitudinal studies, especially studies on bioresorbable scaffolds, because the degradation process will be fully captured independently of the location of the struts and their greyscale appearance.

Inter-observer and intra-observer differences in measuring body length: a test in the common lizard, Zootoca vivipara

AbstractThe snout-vent length (SVL), a conventional measure of overall body size in lizards and snakes, is used in a wide variety of ecological, evolutionary, and taxonomical studies. Trends in SVL variation are often analysed using data from several researchers (observers), but possible confounding effects due to inter-observer differences in measurement protocols have never been appropriately examined. This study reports inter-observer biases between eleven herpetologists who measured the same specimens of the Eurasian common lizards (21 adult specimens were examined by eight observers and additional 192 specimens by two observers). Intra-observer bias over time (1.5-15 months between measuring sessions) was also estimated. In the vast majority of comparisons, mean difference between the first author and another observer varied from −1.0 to +0.8 mm, or from −1.9 to +1.6% if expressed as a percent of the specimen's SVL value. Some non-regular effects of sex and study sample on the studied bias were revealed, and their possible reasons are discussed. We are advising the researchers who intensively collect SVL and other morphometric data to consider testing intra-observer and inter-observer biases and to establish etalon samples available for re-examinations.