Interobserver Coefficient Of Variation Research Articles

Modified anteromedial and anterolateral elbow arthroscopy portals show superiority to standard portals in guiding arthroscopic radial head screw fixation.

Arthroscopic fixation of radial head radial head fractures is an appealing alternative to open reduction and internal fixation, which presents the advantage of minimal surgical trauma. The aim of this study was to evaluate if modifications to the standard anteromedial (AM) and anterolateral (AL) portals could allow screw placement for radial head fracture osteosynthesis closer to the plane of the radial head articular surface. Eight fresh-frozen specimens were prepared to mimic arthroscopic setting. Standard AL (ALst) and AM (AMst) and distal AL (ALdi) and AM (AMdi) portals were established. Eleven independent examiners were asked to indicate the optimal trajectory, when aiming to place a cannulated screw parallel to the radial head surface for radial head osteosynthesis. A three-dimensional digital protractor was used to measure the angle between the indicated position and a Kirschner wire placed parallel to the radial head articular surface (α). The Shapiro-Wilk normality test was used to evaluate the normal distribution of the samples. Means, standard deviations, and 95% confidence intervals (95% CI) were calculated for each portal. A coefficient of variation (CoV) was calculated to determine agreement among observers and intra-observer variability. Mean α angles were 25.1 ± 11.5° for AMst, 13.8 ± 4.8° for AMdi, 17.1 ± 13.4° for ALst, -2.6 ± 9.2° for ALdi. No overlapping in the 95% CI of ipsilateral standard and distal portals was observed, indicating that the difference between these means was statistically significant. The distal portals showed smaller inter-observer CoV as compared to the standard ones (AMst: 10.0%; AMdi: 4.6%; ALst: 12.5%; ALdi: 10.6%). Intra-observer CoV was similar for all portals (AMst: 5.5%; AMdi: 6.1%; ALst: 7.7%; ALdi: 7.1%). The use of distal AM and AL portals permits to obtain α angles closer to the radial head articular surface than standard AM and AL portals. This is expected to allow screw placement in a flatter trajectory, which should correlate with a superior biomechanical performance of fixation. Good reproducibility of Kirschner wire placement from distal portals was observer among different examiners. Modifications to the standard AM and AL elbow arthroscopy portals allow to place screws for radial head fracture osteosynthesis in a position which should guarantee superior biomechanical performance of fixation.

A System for the Acquisition and Analysis of Three-Dimensional Data Describing Dental Morphology

Accurate, reproducible three-dimensional (3D) data provide an important contribution to our ability to describe, compare and understand dental morphology but the existing technology is often expensive or has technical limitations. Recently available, inexpensive 3D profilometers interfaced with standard personal computers offer the potential to overcome some of these problems. This technical note describes a system that uses a 3D profilometer and purpose written software to analyse changes in dental morphology resulting from tooth wear. The validity of the derived data was determined by comparing data derived from scans of objects of known dimensions with calculated volumes. These differences were less than 10% from objects that were difficult to scan because of their geometry and were commonly less than 5%. The reproductibility, expressed as intra- and inter-observer coefficients of variation, was less than 1%. The potential applications of systems of this type are outlined.

Independent validation of metric optimized gating for fetal cardiovascular phase-contrast flow imaging.

PurposeTo validate metric optimized gating phase‐contrast MR (MOG PC‐MR) flow measurements for a range of fetal flow velocities in phantom experiments. 2) To investigate intra‐ and interobserver variability for fetal flow measurements at an imaging center other than the original site.MethodsMOG PC‐MR was compared to timer/beaker measurements in a pulsatile flow phantom using a heart rate (∼145 bpm), nozzle diameter (∼6 mm), and flow range (∼130–700 mL/min) similar to fetal imaging. Fifteen healthy fetuses were included for intra‐ and interobserver variability in the fetal descending aorta and umbilical vein.ResultsPhantom MOG PC‐MR flow bias and variability was 2% ± 23%. Accuracy of MOG PC‐MR was degraded for flow profiles with low velocity‐to‐noise ratio. Intra‐ and interobserver coefficients of variation were 6% and 19%, respectively, for fetal descending aorta; and 10% and 17%, respectively, for the umbilical vein.ConclusionPhantom validation showed good agreement between MOG and conventionally gated PC‐MR, except for cases with low velocity‐to‐noise ratio, which resulted in MOG misgating and underestimated peak velocities and warranted optimization of sequence parameters to individual fetal vessels. Inter‐ and intraobserver variability for fetal MOG PC‐MR imaging were comparable to previously reported values.

Identification and quantification of human microcirculatory leukocytes using handheld video microscopes at the bedside.

Leukocyte recruitment and adhesion to the endothelium are hallmarks of systemic inflammation that manifest in a wide range of diseases. At present, no method is available to directly measure leukocyte kinetics at the bedside. In this study, we validate a new method to identify and quantify microcirculatory leukocytes observed by handheld vital microscopy (HVM) using space-time diagram (STD) analysis. Video clips ( n = 59) containing one capillary-postcapillary venule unit where leukocytes could be observed emanating from a capillary into a venule in cardiac surgery patients ( n = 20) were included. STD analysis and manual counting were used to quantify the number of leukocytes (total, rolling, and nonrolling). Pearson's correlation and Bland-Altman analysis were used to determine agreement between the STDs and manual counting. For reproducibility, intra- and interobserver coefficients of variation (CVs) were assessed. Leukocyte (rolling and nonrolling) and red blood cell velocities were assessed. The STDs and manual counting procedures for the quantification of rolling leukocytes showed good agreement ( r = 0.8197, P < 0.0001), with a Bland-Altman analysis mean difference of -0.0 (-6.56; 6.56). The overall intraobserver CV for the STD method was 1.5%. The overall interobserver CVs for the STD and the manual method were 5.6% and 9.4%, respectively. The nonrolling velocity was significantly higher than the rolling velocity (812 ± 519 µm/s vs. 201 ± 149 µm/s, P = 0.001). STD results agreed with the manual counting procedure results, had a better reproducibility, and could assess the leukocyte velocity. STD analysis using bedside HVM imaging presented a new methodology for quantifying leukocyte kinetics and functions in the microcirculation. NEW & NOTEWORTHY In this study, we introduce space-time diagram analysis of sublingual microcirculation imaging using handheld vital microscopy to identify and quantify the presence and kinetics of human microcirculatory leukocytes. We validated the methodology by choosing anatomical units consisting of a capillary connected to a venule, which allowed precise identification of leukocytes.

Comparison of cardiac measurements by multi-detector computed tomography angiography and transthoracic echocardiography in English bulldogs

IntroductionTransthoracic echocardiography (TTE) is the primary tool for the assessment of cardiac structure and function in dogs but is challenging in English bulldogs due to dorsoventral compression of the thorax, obesity, and narrow intercostal spaces. Multi-detector computed tomography angiography (CTA) may overcome the conformational obstacles of cardiac imaging in this breed. AnimalsEleven client-owned English bulldogs. Materials and MethodsProspective clinical trial with paired analysis of TTE and CTA studies. ResultsEight of the 25 linear cardiac dimensional measurements were significantly different between TTE and CTA (p<0.033). Intraobserver agreement was strong with average coefficients of variation (CV) of 5.34% for TTE and 2.50% for CTA. Interobserver agreement CV averaged 6.5% for TTE and 8.75% CTA. Ejection fraction, stroke volume, and end-systolic volume were significantly different between modalities (all p<0.002). No significant difference was present between end-diastolic volume for TTE compared with CTA. DiscussionHigh-quality cardiac angiographic studies were accomplished using CTA without the use of general anesthesia in English bulldogs. Multi-detector computed tomography angiography and TTE are not interchangeable modalities in the clinical setting. ConclusionMulti-detector-CT ECG-gated cardiac angiography is possible in sedated, non-intubated English bulldogs. Differences were found between some cardiac dimensions as measured by TTE in the awake dog and compared with sedated CTA, indicating the two methodologies are not equivalent. Sedated, non-intubated CTA yielded high-quality imaging with strong intraobserver and interobserver measurement repeatability in English bulldogs.

Development and validation of a rapid and robust method to determine visceral adipose tissue volume using computed tomography images.

BackgroundVisceral adiposity is a risk factor for many chronic diseases. Existing methods to quantify visceral adipose tissue volume using computed tomographic (CT) images often use a single slice, are manual, and are time consuming, making them impractical for large population studies. We developed and validated a method to accurately, rapidly, and robustly measure visceral adipose tissue volume using CT images.MethodsIn-house software, Medical Executable for the Efficient and Robust Quantification of Adipose Tissue (MEERQAT), was developed to calculate visceral adipose tissue volume using a series of CT images within a manually identified region of interest. To distinguish visceral and subcutaneous adipose tissue, ellipses are drawn through the rectus abdominis and transverse abdominis using manual and automatic processes. Visceral and subcutaneous adipose tissue volumes are calculated by counting the numbers of voxels corresponding to adipose tissue in the region of interest. MEERQAT’s ellipse interpolation method was validated by comparing visceral adipose volume from 10 patients’ CT scans with corresponding results from manually delineated scans. Accuracy of visceral adipose quantification was tested using a phantom consisting of animal fat and tissues. Robustness of the method was tested by determining intra-observer and inter-observer coefficients of variation (CV).ResultsThe mean difference in visceral adipose tissue volume between manual and elliptical delineation methods was -0.54 ± 4.81%. In the phantom, our measurement differed from the known adipose volume by ≤ 7.5% for all scanning parameters. Mean inter-observer CV for visceral adipose tissue volume was 0.085, and mean intra-observer CV for visceral adipose tissue volume was 0.059.ConclusionsWe have developed and validated a robust method of accurately and quickly determining visceral adipose tissue volume in any defined region of interest using CT imaging.

The repeatability and characteristics of right ventricular longitudinal strain imaging by speckle-tracking echocardiography in healthy dogs

IntroductionTo assess the repeatability and characteristics of echocardiographic indices of the right ventricular (RV) function derived from speckle-tracking echocardiography. AnimalsFourteen laboratory Beagles and 103 privately owned dogs without cardiac disease were involved in this study. Materials and methodsRight ventricular longitudinal strain, strain rate, and a strain-related index for assessing RV dyssynchrony derived from speckle-tracking echocardiography were obtained by two different observers using five Beagles. Within-day, between-day, and interobserver coefficients of variation and the intraclass correlation coefficient of speckle-tracking echocardiography indices were determined. Both speckle-tracking echocardiography and conventional indices of RV function, including the peak velocity of systolic tricuspid annular motion, tricuspid annulus plane systolic excursion, fractional area change, and the Tei index, were obtained from 14 Beagles and 103 privately owned dogs. Relationships between echocardiographic indices and the body weight, heart rate, age, and sex were estimated by regression analysis. ResultsSpeckle-tracking echocardiographic indices showed good within-day repeatability, between-day and interobserver repeatability were moderate to good. In large dogs, RV longitudinal strain, strain rate, and fractional area change were significantly decreased, while the index of RV dyssynchrony, systolic tricuspid annular motion, tricuspid annulus plane systolic excursion, and the Tei index were increased. All speckle-tracking and conventional echocardiographic indices were correlated with the body weight. Discussion and conclusionsThe speckle-tracking echocardiography indices were highly repeatable and body weight affected speckle-tracking echocardiography indices in dogs. Further studies are needed to apply speckle-tracking echocardiography indices in dogs with cardiac disease.

Validation study of a new semi-automated software program for CT body composition analysis.

Computed tomography (CT) has been increasingly used to quantify abdominal muscle and fat in clinical research studies, and multiple studies have shown importance of body composition in predicting clinical outcome. The purpose of study is to compare newly developed semi-automated software (BodyCompSlicer) to commercially available validated software (Slice-O-Matic) for CT body composition analysis. CT scans of abdomen at L3 level in 30 patients were analyzed by two reviewers and using two softwares (BodyCompSlicer and Slice-O-Matic). Body composition analysis using BodyCompSlicer was semi-automated. The program automatically segmented subcutaneous fat (SF), skeletal muscle (SM), and visceral fat (VF) areas. Reviewers manually corrected the segmentation using computer-mouse interface as necessary. Body composition analysis using Slice-O-Matic was performed by manually segmenting each area using computer-mouse interface (brush tool). After segmentation, SM, SF, and VF areas were calculated using CT attenuation thresholds. Inter-observer and inter-software variability of measurements were analyzed using intraclass correlation coefficients (ICC) and coefficient of variation (COV). Inter-observer ICC and COV using BodyCompSlicer were 0.997 and 1.5% for SM, 1.000 and 0.8% for SF, and 1.000 and 1.0% for VF, whereas those using Slice-O-Matic were 0.993 and 2.5% for SM, 0.995 and 3.1% for SF, and 0.999 and 2.3% for VF. Inter-software ICCs and COV were 0.995-0.995 and 2.0-2.1% for SM, 0.991-0.994 and 3.4-3.9% for SF, and 0.998-0.998 and 2.8-3.3% for VF. Time to analyze 30 cases was 70-100min and 150-180min using BodyCompSlicer and Slice-O-Matic, respectively. BodyCompSlicer is comparable to Slice-O-Matic for CT body composition analysis.

Aortic Volumetry at Contrast-Enhanced Magnetic Resonance Angiography: Feasibility as a Sensitive Method for Monitoring Bicuspid Aortic Valve Aortopathy.

Bicuspid aortic valve patients can develop thoracic aortic aneurysms and therefore require serial imaging to monitor aortic growth. This study investigates the reliability of contrast-enhanced magnetic resonance angiography (CEMRA) volumetry compared with 2-dimensional diameter measurements to identify thoracic aortic aneurysm growth. A retrospective, institutional review board-approved, and Health Insurance Portability and Accountability Act-compliant study was conducted on 20 bicuspid aortic valve patients (45 ± 8.9 years, 20% women) who underwent serial CEMRA with a minimum imaging follow-up of 11 months. Magnetic resonance imaging was performed at 1.5 T with electrocardiogram-gated, time-resolved CEMRA. Independent observers measured the diameter at the sinuses of Valsalva (SOVs) and mid ascending aorta (MAA) as well as ascending aorta volume between the aortic valve annulus and innominate branch. Intraobserver/interobserver coefficient of variation (COV) and intraclass correlation coefficient (ICC) were computed to assess reliability. Growth rates were calculated and assessed by Student t test (P < 0.05, significant). The diameter of maximal growth (DMG), defined as the diameter at SOV or MAA with the faster growth rate, was recorded. The mean time of follow-up was 2.6 ± 0.82 years. The intraobserver COV was 0.01 for SOV, 0.02 for MAA, and 0.02 for volume (interobserver COV: 0.02, 0.03, 0.04, respectively). The ICC was 0.83 for SOV, 0.86 for MAA, 0.90 for DMG, and 0.95 for volume. Average aortic measurements at baseline and (follow-up) were 42 ± 3 mm (42 ± 3 mm, P = 0.11) at SOV, 46 ± 4 mm (47 ± 4 mm, P < 0.05) at MAA, and 130 ± 23 mL (144 ± 24 mL, P < 0.05). Average size changes were 0.2 ± 0.6 mm/y (1% ± 2%) at SOV, 0.5 ± 0.8 mm/y (1% ± 2%) at MAA, 0.7 ± 0.7 mm/y (2% ± 2%) at DMG, and 6 ± 3 mL/y (4% ± 3%) with volumetry. Three-dimensional CEMRA volumetry exhibited a larger effect when examining percentage growth, a better ICC, and a marginally lower COV. Volumetry may be more sensitive to growth and possibly less affected by error than diameter measurements.

Feasibility and reliability of carotid intima-media thickness measurements in nonsedated infants.

Carotid intima-media thickness (CIMT) is a surrogate marker for atherosclerosis. It is increased in adolescents and young adults at risk for future cardiovascular disease. However, it remains unclear if it can be considered as a surrogate marker for atherosclerosis in infancy as very few studies have been performed in infants. Our objective was to assess the feasibility and interobserver reproducibility of CIMT measurement in nonsedated infants. We measured CIMT in 81 infants less than 1 year of age. Repeated measurements were obtained by a second observer in 24 children. The analysis was performed with semiautomated edge detection software. Measurements with over 95% edge detection over a length of 1 cm were considered as valid. We further compared the measurements using the semiautomated method with measurements using the manual electronic caliper method in a subgroup of 10 infants. Carotid ultrasound recordings and intima-media thickness measurements were obtained in 79% of infants (n = 64). Mean CIMT of the 64 infants measured by the first observer was 0.44 mm (SD: 0.04). In the 24 participants with measurements by two observers, the mean interobserver difference was 0.001 mm (SD: 0.026). The interobserver coefficient of variation was 5.9%. CIMT measurements obtained with the manual method (mean: 0.35; range: 0.29-0.39) were slightly lower than measurements obtained with the semiautomated method (mean: 0.38; range: 0.32-0.44). Measurements with both methods were highly correlated (r: 0.87). Measurement of CIMT in nonsedated infants less than 1 year of age is feasible in the majority of infants with good interobserver variability.

Reliability of Pentacam HR Thickness Maps of the Entire Cornea in Normal, Post–Laser In Situ Keratomileusis, and Keratoconus Eyes

To measure the repeatability and reproducibility of Pentacam HR system thickness maps for the entire cornea in normal, post-laser insitu keratomileusis (post-LASIK), and keratoconus (KC) eyes. Reliability study. Sixty normal subjects (60 eyes), 30 post-LASIK subjects (60 eyes), and 14 KC patients (27 eyes) were imaged with the Pentacam HR system by 2 well-trained operators. For pachymetry the cornea was divided into 4 zones: a central zone (2-mm diameter) and concentric pericentral zone (2-5mm), transitional zone (5-7mm), and peripheral zone (7-10mm). The 3 concentric zones were subdivided into 8 sectors. Intraobserver repeatability and interobserver reproducibility of entire corneal thickness maps were tested by the repeatability and reproducibility coefficients, intraclass correlation coefficients, coefficient of variation, and 95% limits of agreement. From central to peripheral zones, the precision of corneal thickness measurements became gradually smaller. Central zone repeatability and reproducibility were the best in the normal, post-LASIK, and KC groups. The peripheral superior sectors showed poorer repeatability and reproducibility for all subjects. The intraobserver repeatability and interobserver reproducibility for all zones were ≤19.3μm, ≤22.1μm, and ≤20.7μm, in the normal, post-LASIK, and KC groups, respectively. The intraobserver and interobserver coefficients of variation for all zones were ≤1.3%, ≤1.6%, and ≤1.6% for all 3 groups. Pentacam HR system pachymetry of the entire cornea provided good precision in normal, post-LASIK, and KC corneas. Thickness measurements in the peripheral cornea should be interpreted with caution in abnormal corneas after surgery or with diseases.

Non-invasive volumetric assessment of aortic atheroma: a core laboratory validation using computed tomography angiography.

Aortic atherosclerosis has been linked with worse peri- and post-procedural outcomes following a range of aortic procedures. Yet, there are currently no standardized methods for non-invasive volumetric pan-aortic plaque assessment. We propose a novel means of more accurately assessing plaque volume across whole aortic segments using computed tomography angiography (CTA) imaging. Sixty patients who underwent CTA prior to trans-catheter aortic valve implantation were included in this analysis. Specialized software analysis (3mensio Vascular™, Pie Medical, Maastricht, Netherlands) was used to reconstruct images using a centerline approach, thus creating true cross-sectional aortic images, akin to those images produced with intravascular ultrasonography. Following aortic segmentation (from the aortic valve to the renal artery origin), atheroma areas were measured across multiple contiguous evenly spaced (10 mm) cross-sections. Percent atheroma volume (PAV), total atheroma volume (TAV) and calcium score were calculated. In our populations (age 79.9 ± 8.5 years, male 52 %, diabetes 27 %, CAD 84 %, PVD 20 %), mean ± SD number of cross sections measured for each patient was 35.1 ± 3.5 sections. Mean aortic PAV and TAV were 33.2 ± 2.51 % and 83,509 ± 17,078 mm(3), respectively. Median (IQR) calcium score was 1.5 (0.7-2.5). Mean (SD) inter-observer coefficient of variation and agreement for plaque area among 4 different analysts was 14.1 (5.4), and the mean (95 % CI) Lin's concordance correlation coefficient was 0.79 (0.62-0.89), effectively simulating a Core Laboratory scenario. We provide an initial validation of cross-sectional volumetric aortic atheroma assessment using CTA. This proposed methodology highlights the potential for utilizing non-invasive aortic plaque imaging for risk prediction across a range of clinical scenarios.

0333: Variability of right ventricular strain derived from speckle-tracking analysis using two different software solutions

Speckle tracking imaging is a recent technique that can be achieved using either vendor dependent or vendor-independent software. Right ventricular (RV) strain is increasingly used as a prognostic tool in both left and right ventricular diseases. Only little is known regarding the variability of vendor-dependent and - independent speckle-tracking imaging software in the assessment of RV free wall longitudinal strain (RLS). The aim of our study was to compare a vendor-dependent (Qlab 9.0, Philips Medical System, Andover, MA, USA) and - independent (Cardiac Performance Analysis, Tomtec Imaging Systems, Germany) software for RLS analysis. We prospectively enrolled 90 consecutive patients with pulmonary hypertension (mean age 55,8±19years) and 26 control patients (mean age 33,9±13years) who underwent a comprehensive echocardiogram including a RV focused 4-chamber view optimised for speckle-tracking analysis. DICOM data sets were stored and analysed by 2 different cardiologists using Qlab and TomTec, blindly to the context and each other. In the whole population, mean RLS was -17,3%±9 and -8,6% ±7,2 respectively using Qlab and Tomtec. Qlab and Tomtec intra-observer coefficients of variation (CV) were -13,19% and -9,56% and interobserver CVs were -22% and -15% respectively. The concordance correlation coefficient was 0,55, indicating poor agreement between the two methods. In the control population, Qlab CV was - 3,63%, whereas CV was -17,8% in RV disease patients. Despite an acceptable level of variability for both techniques, Tomtec appears less variable. Variability of Qlab is excellent in control patients but is highly influenced by RV morphology. The agreement between the two software products is low and should lead in clinical practice to the follow-up of patients with the same software and advocates for the development of dedicated RV speckle-tracking software products.

Quantitative oxygen extraction fraction from 7-Tesla MRI phase: reproducibility and application in multiple sclerosis.

Quantitative oxygen extraction fraction (OEF) in cortical veins was studied in patients with multiple sclerosis (MS) and healthy subjects via magnetic resonance imaging (MRI) phase images at 7 Tesla (7 T). Flow-compensated, three-dimensional gradient-echo scans were acquired for absolute OEF quantification in 23 patients with MS and 14 age-matched controls. In patients, we collected T2*-weighted images for characterization of white matter, deep gray matter, and cortical lesions, and also assessed cognitive function. Variability of OEF across readers and scan sessions was evaluated in a subset of volunteers. OEF was averaged from 2 to 3 pial veins in the sensorimotor, parietal, and prefrontal cortical regions for each subject (total of ~10 vessels). We observed good reproducibility of mean OEF, with intraobserver coefficient of variation (COV)=2.1%, interobserver COV=5.2%, and scan-rescan COV=5.9%. Patients exhibited a 3.4% reduction in cortical OEF relative to controls (P=0.0025), which was not different across brain regions. Although oxygenation did not relate with measures of structural tissue damage, mean OEF correlated with a global measure of information processing speed. These findings suggest that cortical OEF from 7-T MRI phase is a reproducible metabolic biomarker that may be sensitive to different pathologic processes than structural MRI in patients with MS.

130 Reproducibility of T1 and T2 Mapping in Health and Disease, and Assessment of T2 Variability Across the Normal Myocardium

BackgroundT1 and T2 mapping detect myocardial fibrosis and oedema respectively. T1 values show segmental variation in mid ventricular SAX slice, making the identification of regional pathology difficult.We tested the reproducibility...

Validation of a semiautomated spinal cord segmentation method

To validate semiautomated spinal cord segmentation in healthy subjects and patients with neurodegenerative diseases and trauma. Forty-nine healthy subjects, as well as 29 patients with amyotrophic lateral sclerosis, 19 with spinal muscular atrophy, and 14 with spinal cord injuries were studied. Cord area was measured from T2 -weighted 3D turbo spin echo images (cord levels from C2 to T9) using the semiautomated segmentation method of Losseff et al (Brain [1996] 119(Pt 3):701-708), compared with manual segmentation. Reproducibility was evaluated using the inter- and intraobserver coefficient of variation (CoV). Accuracy was assessed using the Dice similarity coefficient (DSC). Robustness to initialization was assessed by simulating modifications to the contours drawn manually prior to segmentation. Mean interobserver CoV was 4.00% for manual segmentation (1.90% for Losseff's method) in the cervical region and 5.62% (respectively 2.19%) in the thoracic region. Mean intraobserver CoV was 2.34% for manual segmentation (1.08% for Losseff's method) in the cervical region and 2.35% (respectively 1.34%) in the thoracic region. DSC was high (0.96) in both cervical and thoracic regions. DSC remained higher than 0.8 even when modifying initial contours by 50%. The semiautomated segmentation method showed high reproducibility and accuracy in measuring spinal cord area.

Excellent inter- and intra-observer reproducibility of microvascular tests using laser speckle contrast imaging

Post-occlusive reactive hyperaemia (PORH) and vasodilation induced by acetylcholine (ACh) iontophoresis are tests of endothelial function that can be studied with laser speckle contrast imaging (LSCI). LSCI has the advantage of having good temporal and spatial resolutions but can lead to a high amount of data when several minutes of recordings are needed. Parameters of PORH and ACh iontophoresis vasodilation are therefore often determined by several observers or by the same observer on different days. Nevertheless, inter- and intra-observer reproducibility for the determination of such parameters has not been studied yet. We analyzed inter-observer and intra-observer reproducibility of baseline, peak and plateau determination for the two microvascular tests. Ten recordings of both PORH and ACh iontophoresis have been analyzed by two blinded trained observers. For peak determination, inter-observer coefficient of variation (CV) was 4.7% and 3.0% for PORH and ACh respectively. Intra-observer reproducibility expressed in CV ranges from 2.4% to 5.4% for PORH-peak and ACh-peak. CVs for peak determination are better than for baseline or plateau determination for both microvascular tests. This suggests that when microvascular vasodilations are reported, the data segments measured have to be noted. Finally microvascular tests using LSCI have an excellent intra- and inter-observer reproducibility.

Diffusion-weighted magnetic resonance imaging for assessment of lung lesions: repeatability of the apparent diffusion coefficient measurement

To establish repeatability of apparent diffusion coefficients (ADCs) acquired from free-breathing diffusion-weighted magnetic resonance imaging (DW-MRI) in malignant lung lesions and investigate effects of lesion size, location and respiratory motion. Thirty-six malignant lung lesions (eight patients) were examined twice (1- to 5-h interval) using T1-weighted, T2-weighted and axial single-shot echo-planar DW-MRI (b = 100, 500, 800 s/mm(2)) during free-breathing. Regions of interest around target lesions on computed b = 800 s/mm(2) images by two independent observers yielded ADC values from maps (pixel-by-pixel fitting using all b values and a mono-exponential decay model). Intra- and inter-observer repeatability was assessed per lesion, per patient and by lesion size (> or <2 cm) or location. ADCs were similar between observers (mean ± SD, 1.15 ± 0.28 × 10(-3) mm(2)/s, observer 1; 1.15 ± 0.29 × 10(-3) mm(2)/s, observer 2). Intra-observer coefficients of variation of the mean [median] ADC per lesion and per patient were 11% [11.4%], 5.7% [5.7%] for observer 1 and 9.2% [9.5%], 3.9% [4.7%] for observer 2 respectively; inter-observer values were 8.9% [9.3%] (per lesion) and 3.0% [3.7%] (per patient). Inter-observer coefficient of variation (CoV) was greater for lesions <2 cm (n = 20) compared with >2 cm (n = 16) (10.8% vs 6.5% ADCmean, 11.3% vs 6.7% ADCmedian) and for mid (n = 14) vs apical (n = 9) or lower zone (n = 13) lesions (13.9%, 2.7%, 3.8% respectively ADCmean; 14.2%, 2.8%, 4.7% respectively ADCmedian). Free-breathing DW-MRI of whole lung achieves good intra- and inter-observer repeatability of ADC measurements in malignant lung tumours. • Diffusion-weighted MRI of the lung can be satisfactorily acquired during free-breathing • DW-MRI demonstrates high contrast between primary and metastatic lesions and normal lung • Apparent diffusion coefficient (ADC) measurements in lung tumours are repeatable and reliable • ADC offers potential in assessing response in lung metastases in clinical trials.

Intraobserver and interobserver agreement of computer software-assisted optic nerve head photoplanimetry

To report the reproducibility profile of optic nerve head parameters obtained by computer software-assisted fundus photoplanimetry. Fundus photographs obtained during a population-based health survey (Sakurae Study) were planimetrically analyzed using newly developed computer software, CDSketch. The parameters assessed included vertical and horizontal cup-to-disc (C/D) ratios, superior and inferior rim-to-disc (R/D) ratios, disc and cup vertical-to-horizontal (V/H) ratios, and disc-macular distance-to-disc diameter (DM/DD) ratio. For intraobserver and interobserver agreement assessments, we calculated the coefficients of variation (CVs) and intraclass correlation coefficients (ICCs) of the mean of three measurements obtained by one observer and a one-time measurement by three observers, respectively. The intraobserver CVs were between 2.4 % (DM/DD ratio) and 11.0 % (inferior R/D ratio), and the ICCs were between 0.868 (cup V/H ratio) and 0.976 (DM/DD ratio); all intraobserver ICCs had almost perfect agreement (>0.81). The interobserver CVs were between 2.6 % (disc V/H ratio) and 18.0 % (inferior R/D ratio), and the ICCs were between 0.762 (cup V/H ratio) and 0.930 (DM/DD ratio); the interobserver ICCs were categorized as substantial (0.61-0.80) for the inferior R/D and cup V/H ratios and as almost perfect for the other five parameters. The consistent profiles of the planimetric parameters suggest the suitability of software-assisted photoplanimetry for assessing optic disc characteristics in glaucoma clinical study and practice.

Impact of delineation uncertainties on dose to organs at risk in CT-guided intracavitary brachytherapy

This study quantifies the inter- and intraobserver variations in contouring the organs at risk (OARs) in CT-guided brachytherapy (BT) for the treatment of cervical carcinoma. The dosimetric consequences are reported in accordance with the current Gynecological Groupe Européen de Curiethérapie/European Society for Therapeutic Radiology and Oncology guidelines. A CT planning study of 8 consecutive patients undergoing image-guided BT was conducted. The bladder, rectum, and sigmoid were contoured by five blinded observers on two identical anonymized scans of each patient. This provided 80 data sets for analysis. Dosimetric parameters analyzed were D0.1 cc, D1 cc, and D2 cc. The mean volume of each OAR was calculated. These endpoints were compared between and within the observers. The CT image sets from all patients were evaluated qualitatively. The interobserver coefficient of variation for reported D2 cc was 13.2% for the bladder, 9% for the rectum, and 19.9% for the sigmoid colon. Unlike the variation seen in bladder and rectal contours, which differed largely in localization of the organ walls on individual slices, sigmoid colon contours demonstrated large differences in anatomic interpretation. Variation in recorded D2 cc to the bladder and rectum is comparable with the previous published results. Inter- and intraphysician variations in reported D2 cc is high for the sigmoid colon, reflecting varying interpretation of sigmoid colon anatomy. Variation in delineation of the OARs may influence treatment optimization and is a potential source of uncertainty in the image-guided BT planning and delivery process.