Interobserver Repeatability Research Articles

A practical tool for locomotion scoring in sheep: reliability when used by veterinary surgeons and sheep farmers

A four-point locomotion scoring tool for sheep was developed and tested on 10 general practice veterinary surgeons (VS) and 10 sheep farmers. Thirty-four video clips of sheep displaying different locomotion...

Exploring Noninvasive Tricuspid dP/dt as a Marker of Right Ventricular Function.

Right ventricular (RV) function assumes prognostic significance in various disease states, but RV geometry is not amenable to volumetric assessment by two-dimensional echocardiography. Intra-ventricular pressure rate of rise (dP/dt) predicts myocardial contractility and adjusting for the maximal regurgitant velocity (Vmax) corrects for preload. We examined the relationship of noninvasive tricuspid dP/dt and dP/dt/Vmax with RV ejection fraction (RVEF) by cardiac magnetic resonance imaging (CMR) as a measure of RV function. Fifty CMRs and echocardiograms performed within 30 days were included. Tricuspid regurgitation (TR) spectral Doppler trace was analyzed offline. TR dP/dt was calculated using simplified Bernoulli equation (dP/dt between 1 and 2 m/sec). dP/dt/Vmax was calculated as a ratio of dP/dt and TR Vmax . RV end-diastolic (EDV) and end-systolic volumes (ESV) were obtained from contouring of steady-state-free precession axial stack CMR images; RVEF was calculated as [(RVEDV - RVESV)/RVEDV] × 100. RVEF >42% was considered normal. Majority of studies were suitable for analysis. Median age was 48 years (IQR = 36-63); 56.4% were female (n = 22/39). There was correlation between dP/dt and RVEF (r(2) = 0.51, P < 0.01) which improved with dP/dt/Vmax (r(2) = 0.59, P < 0.01). dP/dt >400 mmHg/sec had a positive predictive value of 91%, sensitivity and specificity of 74% and 84% respectively for normal RVEF. Inter-observer agreement and repeatability analysis showed no significant difference. Tricuspid dP/dt correlates well with CMR RVEF. A dP/dt of more than 400 mmHg/sec strongly predicts normal RVEF. Adjusting for preload (dP/dt/Vmax) further improves this correlation.

Repeatability of the Oxford Foot Model for Kinematic Gait Analysis of the Foot and Ankle

Introduction: Kinematic gait analysis via the multi-segmental Oxford foot model (OFM) may be a valuable addition to the biomechanical examination of the foot and ankle. The aim of this study is to assess the repeatability of the OFM in healthy subjects. Methods: Nine healthy subjects, without a history of lower extremity injury, were recruited. Markers were placed according to the OFM requirements. Motion capture was conducted using the VICON NEXUS system on two separate test days, with two tests on each day conducted by two independent examiners. The range of motion (ROM) of the following inter-segments was selected for further analysis: forefoot-hindfoot, forefoot-tibia and hindfoottibia in frontal, sagittal and transverse planes. Each step was divided in two parts, a loading phase (from heel strike to midstance) and a push-off phase (from midstance to toe-off). The Intraclass correlation coefficient (ICC), standard error of the measurements with 90% confidence bounds (SEM90) and the Minimal Differences needed to be considered real (MD) with 95% confidence interval were calculated for inter-observer and intra-observer and effect of trial using SPSS. Results: There was a linear correlation between the number of trials and the ICC's (r2=0.49, p<0.001), with six trial leading to good ICC's. Inter-observer repeatability: In the loading phase almost all ICC's were good or excellent (0.53-0.97) with only one parameter below 0.60. In the push-off phase two parameters scored moderate agreement, where the other 7 parameters had well to excellent agreement. The SEM90 values were varying from 0.85° to 2.49° in the loading phase and from 0.92° to 4.40° in the push-off phase Intra-observer repeatability: In the loading phase all ICC's were good or excellent (0.71-0.97). In the push-off phase two parameters scored moderate agreement and the other 7 parameters had well to excellent agreement. The SEM90 ranged from 1.15° to 4.53° in the loading phase and in the push-off phase from 1.71° to 5.49°. The SEM90 values were varying from 0.85° to 2.49° in the loading phase and from 0.92° to 4.40° in the push-off phase. Intra-observer repeatability: In the loading phase all ICC's were good or excellent (0.71-0.97). In the push-off phase two parameters scored moderate agreement and the other 7 parameters had good to excellent agreement. Conclusion: The repeatability analysis presented in this study provide excellent basis for objective measurement of the ankle and foot biomechanics. Results for inter-observer and intra-observer repeatability showed moderate to excellent ICC's and acceptable SEM90. Best result were found in the sagittal plane (flexion/extension) followed by the frontal plane (abduction/adduction) and the transverse plane (inversion/eversion).

117 IN VIVO EVALUATION OF THE CERVICAL STIFFNESS EVOLUTION DURING INDUCED LABOR IN EWES USING ELASTOGRAPHY

Despite numerous advances and intensive research in perinatal medicine, spontaneous preterm birth (PTB) is the leading global cause of neonatal mortality and morbidity. On the other hand, labour has to be induced in ~23% of pregnancies worldwide. Both issues may be related to the distensibility of the cervical tissue. Quantitative and objective monitoring of the cervix ripening may provide a complementary method to identify cases at risk of PTB and assess the likelihood of successful induction of labour. Currently, however, no reliable clinical tools for such a quantitative and objective evaluation exist. Elastography aims at imaging tissue stiffness. All elastography techniques rely on the same basics: an external force is applied to the tissue and the resulting movements are then followed. Supersonic shear imaging (SSI) is a dynamic method that uses the propagation of mechanical waves to excite the tissue. Its speed is tracked then by ultrafast imaging, allowing characterisation of stiffness [Bercoff et al. 2004 IEEE Trans. Ultrason. Ferroelect. Freq. Contr. 51, 396–409]. Understanding the mechanisms that take place in normal pregnancy will allow a better comprehension of the cervical remodelling and lead to better methods of diagnosis of PTB and successful induction of labour. In this work, we propose a preliminary assessment of the evolution of stiffness during the cervical maturation process in the sheep. The main goal was to study the feasibility of elastography using SSI to quantify cervical stiffness during the maturation process and to assess the potential of this technique for diagnosis of preterm labour and for labour induction success. Cervical stiffness was quantified, by 2 different operators, in 9 pregnant ewes in vivo by using SSI. The cervical ripening was induced by a dexamethasone injection in 5 animals, and 4 animals constituted the control group. The stiffness of the second ring of the cervix was quantified over a circular region of interest of 5 mm of diameter during vaginal ultrasound examination. Images were acquired every 4 h during 24 h to monitor the cervical maturation induced by the dexamethasone injection. Cervical stiffness was found to decrease significantly throughout the cervical ripening (from 9.5 ± 0.9 kPa to 5.0 ± 0.8 kPa; P = 2.7e–5). The intraobserver and interobserver repeatability of measurements were assessed using Bland-Altman analysis with 95% CI. The principal findings of the study were that elastography measurements using SSI technique were highly reproducible in all cases. Second, stiffness of the uterine cervix decreases throughout the maturation process induced by the dexamethasone injection. Finally, it was possible to quantify the decrease of stiffness through the cervical maturation process. Elastography may be a valuable method to quantify objectively and noninvasively the cervical stiffness in vivo, and ultimately could be a useful tool for the diagnosis of PTB and the assessment of labour induction success.

Two-dimensional longitudinal strains and torsion analysis to assess the protective effects of ischemic postconditioning on myocardial function: A speckle tracking echocardiography study in rabbits

The reperfusion injury that occurs in the early reperfusion often results in myocardial dysfunction. This study evaluated global and regional left ventricular (LV) function using speckle tracking echocardiography (STE) in a rabbit ischemia–reperfusion (I/R) model with and without ischemic postconditioning (I-PostC). The aim is to investigate the potential benefit of I-PostC for myocardial function and validate whether regional longitudinal strain is an appropriate index to indicate myocardial dysfunction. Forty rabbits were divided into an ischemia–reperfusion group (group I) and an I-PostC group (group II). After the coronary arteries were ligated, LV systolic strain and twist parameters decreased, and absolute value of strain rate of isovolumetric relaxation period (SRivr) and post-systolic strain index (PSI) increased significantly in both groups (all p<0.05). After reperfusion, regional longitudinal systolic strain rate (SRsys), systolic strain (Ssys), LV twist and untwisting rate increased, and SRivr and PSI decreased in group II. These changes were not seen in group I. All STE parameters were correlated with area of necrosis (AN)/area at risk (AR) (all p<0.05). The correlations were morerelevant between SRsys and AN/AR (r=−0.673) and between Ssys and AN/AR (r=−0.777) (both p<0.001). The intra- and inter-observer repeatability of STE parameters were good with correlation coefficients (CCs) >0.8 or 0.6. The sensitivities of GSRsys, GSsys, SRsys, Ssys, and LV twist to detect the myocardial infarction were 81.3%, 62.5%, 87.5%, 93.8% and 81.3%, respectively. And the specificities of those parameters were 75.0%, 81.2%, 75.0%, 87.5% and 68.7%. These results indicate that STE is useful for quantitative detection on myocardial function improvement induced by I-PostC in a rabbit I/R model. The regional index—Ssys is an appropriate parameter to indicate myocardial dysfunction because of its sensitivity, specificity, and repeatability.

Influence of choroidal thickness on subfoveal choroidal thickness measurement repeatability using enhanced depth imaging optical coherence tomography

To determine the influence of choroidal thickness (CT) and image setting on repeatability of subfoveal choroidal thickness (SFCT) manual measurement using enhanced depth imaging optical coherence tomography (EDI-OCT). This retrospective study included 189 eyes from 189 adults. Two observers (A and B) measured the SFCT from 1 : 1 micron and 1 : 1 pixel images for evaluation of interobserver repeatability. Observer A performed a single additional measurement for intraobserver repeatability. The mean age was 45.1±11.1 years. The mean SFCT from 1 : 1 pixel and 1 : 1 micron images were 315.3±89.2 and 312.6±88.4 μm, respectively. The subjects were divided into three subgroups based on the mean CT from 1 : 1 pixel images: 26 eyes belonged to thin CT group, 111 eyes to intermediate CT group, and 52 eyes to thick CT group. Interclass coefficients (ICCs) exhibited high intraobserver repeatability. Interobserver ICCs were also high, except for thick CT group with 1 : 1 pixel image (ICC≤0.75). Intraobserver correlation coefficients were high regardless of CT. Interobserver correlation coefficients for 1 : 1 pixel images were 0.896 in thin CT group, 0.680 in intermediate CT group, and 0.624 in thick CT group, respectively (P<0.0001). The interobserver ICCs and correlation coefficients from 1 : 1 micron images were slightly higher than from 1 : 1 pixel images. The repeatability for the two observers was reduced in thick CT group despite high total repeatability. 1 : 1 Micron images provided slightly better repeatability in interobserver measurements. CT measurements should be interpreted cautiously, particularly for a thick choroid.

P15.13: Intraobserver and interobserver repeatability for the volume of intracranial structures using XI VOCAL

To assess intraobserver and interobserver repeatability for the volume of intracranial structures. It was considered the volume of the fetal head circumference (HC), the frontal lobe (FrL) and the cerebellum (Cereb), estimated by XI VOCAL (eXtended Imaging Virtual Organ Computer-aided Analysis) method in fetuses appropriate-for-gestational-age (AGA) and affected by fetal growth restriction (FGR). Transversal study of pregnant women between 24-34 weeks of gestation. The 3D-ultrasound exams were performed by 2 observers, using a V20 equipment (Medison, Seoul, Republic of Korea), provided with convex transducer (4-7 MHz). The scanning angle was set between 50-80° (according to gestational age), the quality of definition was “high” and velocity normal. The intraclass correlation coefficient (ICC) was used for statistical analysis, and also Bland-Altman charts. Twenty four patients were included for repeatability evaluation, 12 AGA and 12 affected by FGR. For intraobserver concordance, the HC ICC was 0,998 (0,994-0,999), the FrL ICC 0,997 (0,993-0,999) and the Cereb ICC 0,997 (0,992-0,999). For interobserver concordance, the HC ICC was 0,999 (0,997-0,999), the FrL ICC 0,997 (0,993-0,999) and the Cereb ICC 0,998 (0,995-0,999). The Bland-Altmand charts confirmed the excellent concordance. There is an excellent concordance for intraobserver and interobserver repeatability in XI VOCAL estimating volume of HC, FrL and Cereb. This tool can be used for evaluation of intracranial structures in both AGA and FGR affected fetuses.

Schlemm's canal expands after trabeculectomy in patients with primary angle-closure glaucoma.

To evaluate the in vivo changes in the Schlemm's canal (SC) in patients with primary angle-closure glaucoma (PACG) after trabeculectomy using spectral-domain optical coherence tomography (SD-OCT). Forty eyes of 40 patients with PACG who underwent trabeculectomy were included. All participants underwent SD-OCT. The diameter and area of SC were examined and measured before and within 1 month after trabeculectomy. All SD-OCT images were processed using adaptive compensation algorithm to improve contrast and image quality. Multivariate linear regression analysis was performed for predictors of percentage change in the mean SC diameter and area. The mean age of participants was 60.5 ± 14.6 years. Adaptive compensation significantly increased the percentage of sections in which SC was observable in the subjects studied from 52.5% (21/40) to 75.0% (30/40), which has acceptable intraobserver and interobserver repeatability. There was a significant increase in the SC diameter and area at the follow-up examination compared with the baseline value (SC diameter: 34.2 ± 6.2 μm vs. 28.4 ± 6.1 μm; SC area: 8117 ± 1942 μm(2) vs. 5200 ± 996 μm(2); all P < 0.001). After multivariate analysis, the only variable related to changes in SC was percentage change in IOP (SC diameter, P = 0.002; SC area, P < 0.001). In addition, the magnitude of the change in the SC area also correlated with angle opening distance at 750 μm from the scleral spur at baseline. Expansion of SC was observed after trabeculectomy in PACG patients. The degree of SC expansion was related to the extent of the IOP decrease.

Choroidal Thickness and Volume in Healthy Young White Adults and the Relationships between them and Axial Length, Ammetropy and Sex

To evaluate choroidal thickness in young adults using enhanced-depth imaging spectral-domain optical coherence tomography and to describe volume differences in all the areas defined in the Early Treatment Diabetic Retinopathy Study. Prospective clinical study. In 95 healthy young (23.8 ± 3.2 years) adult volunteers, 95 eyes were prospectively enrolled. Manual choroidal segmentation on a 25-raster horizontal scan protocol was performed. The measurements of the 9 subfields defined by the Early Treatment Diabetic Retinopathy Study were evaluated. Mean subfoveal choroidal thickness was 345.67 ± 81.80 μm and mean total choroidal volume was 8.99 ± 1.88 mm(3). Choroidal thickness and volume were higher in the superior and temporal areas than in the inferior and nasal sectors of the same diameter, respectively. Strong correlations between subfoveal choroidal thickness and axial length and myopic refractive error were obtained (r = -0.649, P < 0.001, and r = 0.473, P < 0.001, respectively). Emmetropic eyes tended to have thicker subfoveal choroidal thickness (381.94 ± 79.88 μm vs 307.04 ± 64.91 μm) and higher total choroidal volume than myopic eyes (9.80 ± 1.87 mm(3) vs 8.14 ± 1.48 mm(3)). The estimation of the variation in the subfoveal choroidal thickness in relationship to the axial length was -43.84 μm/mm. In the myopic group, the variation in the subfoveal choroidal thickness with the myopic refractive error was -10.45 μm per diopter. This study establishes for the first time a normal database for choroidal thickness and volume in young adults. Axial length, and myopic ammetropy are highly associated with choroidal parameters in healthy subjects. Enhanced-depth imaging spectral-domain optical coherence tomography exhibited a high degree of intraobserver and interobserver repeatability.

Repeatability of grading meibomian gland dropout using two infrared systems.

To determine the interobserver and intraobserver repeatability in using the OCULUS Keratograph 4 (K4) and 5M (K5M) to grade meibomian gland (MG) dropout using meibography grading scales. The inferior and superior eyelids of 40 participants (35 women, 5 men; mean age = 32 years) were imaged three times each on both instruments. The images were split into one training and two study sets; the latter were graded (four-point meibography scale) by two observers on two separate occasions (24 hours apart) to determine repeatability. Semiobjective quantification of percentage MG dropout was conducted using ImageJ on K4 and K5M images. A finer seven-point meibography scale was used to grade a separate set of K5M images. For the four-point scale, interobserver mean difference (MD) (±SD) was 0.08 (±0.55) on day 1 and 0.13 (±0.50) on day 2, and the concordance correlation coefficient (CCC) was 0.79 and 0.81 on days 1 and 2, respectively. Intraobserver MD (±SD) was 0.04 (±0.54), CCC = 0.79 for observer 1; intraobserver MD (±SD) was -0.09 (±0.60), CCC = 0.74 for observer 2. For the seven-point scale, interobserver MD (±SD) was 0.05 (±0.45), CCC = 0.89 on day 1, and interobserver MD (±SD) was 0.01 (±0.41), CCC = 0.91 on day 2. Intraobserver MD (±SD) was -0.10 (±0.35), CCC = 0.93 for observer 1, and intraobserver MD (±SD) was -0.06 (±0.30), CCC = 0.95 for observer 2. Percentage dropout measured between the K4 and K5M images showed lack of agreement, with 21.8% coefficient of repeatability. There was no significant correlation (r < 0.2; p > 0.05) between meibography score and clinical signs (corneal staining, gland expressibility, telangiectasia, vascularity, lash loss); however, there was a high correlation (r = 0.77; p < 0.05) between meibography score with percentage dropout. Observers graded from -1 to +1 grade units between and within themselves for a four-point scale, 95% of the time. Although the interobserver and intraobserver repeatability of the K4 and K5M were very similar, a high rate of disagreement in percentage dropout between K4 and K5M images suggests that the two instruments cannot be interchanged. Meibomian gland dropout scores did not correlate significantly with clinical signs. Using a finer scale may be beneficial for detecting change.

Accuracy of noninvasive, single-plane fluoroscopic analysis for measurement of three-dimensional femorotibial joint poses in dogs.

To compare accuracy of a noninvasive single-plane fluoroscopic technique with radiostereometric analysis (RSA) for determining 3-D femorotibial poses in a canine cadaver with normal stifle joints. Right pelvic limb from a 25-kg adult mixed-breed dog. A CT scan of the limb was obtained before and after metal beads were implanted into the right femur and tibia. Orthogonal fluoroscopic images of the right stifle joint were acquired to simulate a biplanar fluoroscopic acquisition setup. Images were obtained at 5 flexion angles from 110° to 150° to simulate a gait cycle; 5 cycles were completed. Joint poses were calculated from the biplanar images by use of RSA with CT-derived beaded bone models and compared with measurements obtained by use of CT-derived nonbeaded bone models matched to single-plane, lateral-view fluoroscopic images. Single-plane measurements were performed by 2 observers and repeated 3 times by the primary observer. Mean absolute differences between the single-plane fluoroscopic analysis and RSA measurements were 0.60, 1.28, and 0.64 mm for craniocaudal, proximodistal, and mediolateral translations, respectively, and 0.63°, 1.49°, and 1.58° for flexion-extension, abduction-adduction, and internal-external rotations, respectively. Intra- and interobserver repeatability was strong with maximum mean translational and rotational SDs of 0.52 mm and 1.36°, respectively. Results suggested that single-plane fluoroscopic analysis performed by use of CT-derived bone models is a valid, noninvasive technique for accurately measuring 3-D femorotibial poses in dogs.

Application of age estimation methods based on teeth eruption: how easy is Olze method to use?

The development of new methods for age estimation has become with time an urgent issue because of the increasing immigration, in order to estimate accurately the age of those subjects who lack valid identity documents. Methods of age estimation are divided in skeletal and dental ones, and among the latter, Olze's method is one of the most recent, since it was introduced in 2010 with the aim to identify the legal age of 18 and 21 years by evaluating the different stages of development of the periodontal ligament of the third molars with closed root apices. The present study aims at verifying the applicability of the method to the daily forensic practice, with special focus on the interobserver repeatability. Olze's method was applied by three different observers (two physicians and one dentist without a specific training in Olze's method) to 61 orthopantomograms from subjects of mixed ethnicity aged between 16 and 51 years. The analysis took into consideration the lower third molars. The results provided by the different observers were then compared in order to verify the interobserver error. Results showed that interobserver error varies between 43 and 57 % for the right lower third molar (M48) and between 23 and 49 % for the left lower third molar (M38). Chi-square test did not show significant differences according to the side of teeth and type of professional figure. The results prove that Olze's method is not easy to apply when used by not adequately trained personnel, because of an intrinsic interobserver error. Since it is however a crucial method in age determination, it should be used only by experienced observers after an intensive and specific training.

In vivo analysis of the iris thickness by spectral domain optical coherence tomography

PurposeTo assess the effectiveness of spectral domain optical coherence tomography (SD-OCT) in providing in vivo measurements of iris thickness in healthy and pathological subjects.Methods14 healthy volunteers and 14 patients with...

Reproducibility of manifest refraction between surgeons and optometrists in a clinical refractive surgery practice

To measure and compare the interobserver reproducibility of manifest refraction according to a standardized protocol for normal preoperative patients in a refractive surgery practice. Private clinic, London, United Kingdom. Retrospective case series. This retrospective study comprised patients attending 2 preoperative refractions before laser vision correction. The first manifest refraction was performed by 1 of 7 optometrists and the second manifest refraction by 1 of 2 surgeons, all trained using a standard manifest refraction protocol. Spherocylindrical data were converted into power vectors for analysis. The dioptric power differences between observers were calculated and analyzed. One thousand nine hundred twenty-two consecutive eyes were stratified into a myopia group and a hyperopia group and then further stratified by each surgeon-optometrist combination. The mean surgeon-optometrist dioptric power difference was 0.21 diopter (D) (range 0.15 to 0.32 D). The mean difference in spherical equivalent refraction was 0.03 D, with 95% of all refractions within ±0.44 D for all optometrist-surgeon combinations. The severity of myopic or hyperopic ametropia did not affect the interobserver reproducibility of the manifest refraction. There was close agreement in refraction between surgeons and optometrists using a standard manifest refraction protocol of less than 0.25 D. This degree of interobserver repeatability is similar to that in intraobserver repeatability studies published to date and may represent the value of training and the use of a standard manifest refraction protocol between refraction observers in a refractive surgery practice involving co-management between surgeons and optometrists.

Detection of cartilage damage in femoroacetabular impingement with standardized dGEMRIC at 3 T

This study aimed at identifying the optimal threshold value to detect cartilage lesions with Standardized delayed Gadolinium-Enhanced MRI of Cartilage (dGEMRIC) at 3 T and evaluate intra- and inter-observer repeatability. We retrospectively reviewed 20 hips in 20 patients. dGEMRIC maps were acquired at 3 T along radial imaging planes of the hip and standardized to remove the effects of patient's age, sex and diffusion of gadolinium contrast. Two observers separately evaluated 84 Standardized dGEMRIC maps, both by visual inspection and using an average index for a region of interest (ROI) in the acetabular cartilage. A radiologist evaluated the acetabular cartilage on morphologic MR images at exactly the same locations. Using intra-operative findings as reference, the optimal threshold to detect cartilage lesions with Standardized dGEMRIC was assessed and results were compared with the diagnostic performance of morphologic magnetic resonance imaging (MRI). Using z < -2 as threshold and visual inspection of the color-adjusted maps, sensitivity, specificity and accuracy for Observer 1 and Observer 2, were 83%, 60% and 75%, and 69%, 70% and 69%, respectively. Overall performance was 52%, 67% and 58%, when using an average z for the acetabular cartilage, compared to 37%, 90% and 56% for morphologic assessment. The kappa coefficient was 0.76 and 0.68 for intra- and inter-observer repeatability, respectively, indicating substantial agreement. Standardized dGEMRIC at 3 T is accurate in detecting cartilage damage and could improve preoperative assessment in femoroacetabular impingement (FAI). As cartilage lesions in FAI are localized, visual inspection of the Standardized dGEMRIC maps is more accurate than an average z for the acetabular cartilage.

Comparison between palpation and ultrasonography for evaluation of experimentally induced effusion in the distal interphalangeal joint of horses

To ultrasonographically quantify experimentally induced effusion of the distal interphalangeal (DIP) joint of horses and compare results with those obtained with palpation. 8 forelimbs from equine cadavers and forelimbs of 5 mares. Preliminary ex vivo experiments were performed to validate the methods. Then, the DIP joints of the forelimbs of standing horses were serially distended with saline (0.9% NaCl) solution (1, 4, and 10 mL) by injection through an intra-articular catheter. Two ultrasonographers measured distension of the dorsal recess of the DIP joint, and 2 surgeons, who were not aware of the volume injected, graded joint effusion by palpation. Intraobserver and interobserver repeatability was excellent for ultrasonographic measurements. Interobserver agreement for use of palpation to detect joint distension was moderate (κ = 0.45). There was an overall increase in the palpation distension grade with an increase in injected volume. Sensitivity for detection with palpation of larger volumes (4 and 10 mL) was high (92% and 100%, respectively). However, sensitivity was lower (57%) for detection with palpation of minimal distension (1 mL). Although palpation provided a reliable clinical assessment of DIP joint effusion for volumes of 4 to 10 mL, ultrasonographic measurements were easy to obtain, more accurate, and able to detect smaller amounts of distension. This may be clinically relevant for the assessment of effusion of the DIP joint that can arise in horses with early osteoarthritis or infectious arthritis with concomitant soft tissue swelling that precludes accurate assessment with palpation.

Comparison of the inter- and intra-observer repeatability of three gait-scoring scales for sows

Most gait-scoring scales for pigs have a limited number of categories, supposedly to improve repeatability. However, reducing the number of categories could lead to loss of information if the observers’ discriminative capacities are underused. With a recently estimated within-herd prevalence of sow lameness of 8.8% to 16.9% in the European Union and the associated losses, the availability of reliable tools for the timely detection of initial cases warrants attention. This study investigated the intra- and inter-observer repeatability (intra-OR and inter-OR) of three gait-scoring scales for sows: a continuous ‘tagged’ visual analogue scale (tVAS, measured in mm), a 5-point and a 2-point ordinal scale (5P and 2P), all with the same descriptors. Veterinary medicine students (n=108) were trained to use the scales and then asked to score 90 videos (30 per scale) of sows with normal and abnormal gait. Thirty-six videos were shown once and 18 were randomly shown three times, of which one mirrored horizontally. The students’ opinions on the scales were also collected. Intra- and inter-OR were higher with the tVAS than the 2P scale (inter-OR: 0.73 v. 0.60; P<0.05. Intra-OR: 0.80 v. 0.67; P<0.05). Intra-OR was higher with the 5P (0.81) than the 2P scale (0.67; P<0.05). For all three scales, repeatabilities were lower (P<0.05) for non-lame sows (gait score of ⩽45 mm on the tVAS) than for sows showing some signs of lameness (gait score>45 mm). Video order (first 45 v. last 45 clips), mirroring, users’ opinions on the scales, and previous declared experience in handling pigs or scoring lameness in other species had no effect on repeatabilities. Correlations between the students’ and experts’ scores were high (tVAS=0.92; 5P=0.91; 2P=0.88) but the association for the 2P was not linear and the frequency distribution showed lower correlations for a group of students. This study confirms recent evidence that it is possible to design high-resolution gait-scoring scales that do not reduce observer repeatability. Visual gait-scoring scales with fewer than five categories are likely to entail loss of information on lameness in individual sows.

Selection of the Sub-noise Gain Level for Acquisition of VOCAL Data Sets: A Reliability Study

This study was aimed at assessing the intra-observer and inter-observer repeatability of selecting the sub-noise gain (SNG) level when acquiring placental volumes with 3-D power Doppler for analysis using virtual organ computer-aided analysis (VOCAL). Sixty women with uncomplicated singleton pregnancies between 20 and 38 wk of gestation were recruited. Two women were excluded for flash artifact noted during image analysis. Two blinded observers independently adjusted gain to their perceived SNG level before acquiring a static 3-D volume of the placenta at the cord insertion; observers alternated after each acquisition until each had acquired two volumes. A single observer operated the probe at all times. During offline analysis, SNG levels were recorded and VOCAL indices were calculated. SNG exhibited excellent intra-observer and inter-observer reliability. Intra-observer intra-class correlation coefficients (95% confidence intervals) were 0.98 (0.97–0.99) and 0.98 (0.98–0.99) for observers 1 and 2, respectively. The inter-observer intra-class correlation coefficient was 0.96 (0.93–0.98). Despite its perceived inherent subjectivity, the excellent intra-class correlation coefficients obtained in this study support SNG as a promising tool for future research using 3-D power Doppler.

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.

Assessment of pulmonary artery pulse wave velocity in children: An MRI pilot study

PurposeTo assess the feasibility of measuring pulmonary artery (PA) pulse wave velocity (PWV) in children breathing ambient air and 12% oxygen. MethodsVelocity-encoded phase-contrast MR images of the PA were acquired in 15 children, aged 9–12years, without evidence of cardiac or pulmonary diseases. PWV was derived as the ratio of flow to area changes during early systole. Each child was scanned twice, in air and after at least 20minutes into inspiratory hypoxic challenge. Intra-observer and inter-observer variability and repeatability were also compared. ResultsPA PWV, which was successfully measured in all subjects, increased from 1.31±0.32m/s in air to 1.61±0.58m/s under hypoxic challenge (p=0.03). Intra- and inter-observer coefficients of variations were 9.0% and 15.6% respectively. Good correlation within and between observers of r=0.92 and r=0.72 respectively was noted for PA PWV measurements. Mean (95% limit of agreement) intra- and inter-observer agreement on Bland–Altman analysis were −0.02m/s (−0.41–0.38m/s) and -0.28m/s (−1.06–0.49m/s). ConclusionPA PWV measurement in children using velocity-encoded MRI is feasible, reproducible and sufficiently sensitive to detect differences in PA compliance between normoxia and hypoxia. This technique can be used to detect early changes of PA compliance and monitor PAH in children.