Interobserver Coefficient Of Repeatability Research Articles

Arithmetic hip knee angle measurement on long leg radiograph versus computed tomography—inter-observer and intra-observer reliability

BackgroundPre-operative alignment is important for knee procedures including total knee arthroplasty (TKA), especially when considering alternative alignments. The arithmetic Hip Knee Angle (aHKA) is a measure of coronal alignment calculated using the medial proximal tibial (MPTA) and lateral distal femoral angles (LDFA). Traditionally, aHKA is measured on long leg radiographs (LLR). This study assesses the reproducibility of aHKA measurement on LLR and robotic-assisted TKA planning CT.MethodsSixty-eight TKA patients with pre-operative LLR and planning CTs were included. Three observers measured the LDFA, MPTA and aHKA three times on each modality and intra-observer and inter-observer reliability was calculated. Statistical analysis was undertaken with Pearson’s r and the Bland–Altman test.ResultsMean intra-observer coefficient of repeatability (COR) for LLR vs. CT: MPTA 3.50° vs. 1.73°, LDFA 2.93° vs. 2.00° and aHKA 2.88° vs. 2.57° for CT. Inter-observer COR for LLR vs. CT: MPTA 2.74° vs. 1.28°, LDFA 2.31° vs. 1.92°, aHKA 3.56° vs. 2.00°. Mean intra-observer Pearson’s r for MPTA was 0.93 for LLR and 0.94 for CT, LDFA 0.90 for LLR and 0.91 for CT and aHKA 0.92 for LLR and 0.94 for CT. Inter-observer Pearson’s r for LLR compared to CT: MPTA 0.93 vs. 0.97, LDFA 0.91 vs. 0.90, aHKA 0.91 and 0.95.ConclusionWhen compared to LLR, CT measurements of MPTA, LDFA and aHKA are more reproducible and have a good correlation with LLR measurement. CT overcomes difficulties with positioning, rotation, habitus and contractures when assessing coronal plane alignment and may obviate the need for LLRs.

Children treated for developmental dysplasia of the hip at birth and with normal acetabular index at 1 year: How many had residual dysplasia at 5 years?

Purpose:The purpose of the study was to assess the effect of further follow-up for children treated for developmental dysplasia of the hip, with normal clinical and radiological findings at 1-year time point. The effect was quantified by the number of hips with a pathologic deterioration up to 5 years.Methods:Among 47,289 children born in Sør-Trøndelag county in Norway between 2003 and 2015, 265 children had developmental dysplasia of the hip. Of these, 164 children (239 hips) treated for developmental dysplasia of the hip with normal clinical findings and normal acetabular index at the 1-year time point were included in the study. The number of hips with pathologic acetabular index at the 5-year time point were reported. The diagnostic uncertainty related to radiological measurements was quantified together with the effect of introducing a second radiographic measurement, the center edge angle.Results:A total of 239 treated hips were normal at the 1-year time point. At 5-year time point, 10 (4.2%) hips had a pathologic acetabular index measurement and none classified to have developmental dysplasia of the hip caused by measurement inaccuracy. Eight (3.3%) hips had pathologic center edge angle measurement. Four hips had both pathologic acetabular index and center edge angle measurements, with three later treated with surgery. The intra- and interobserver repeatability coefficients were within 3.1°–6.6°.Conclusion:The repeatability coefficient of the acetabular index measurements was high and no hips could be classified to have developmental dysplasia of the hip at the 5-year time point when taking this repeatability into account. Hips classified as pathologic combining acetabular index and center edge angle measurements were likely to be treated with surgery for residual dysplasia. We recommend further follow-up for these children.Level of evidence:level II.

The quantitative measurements of choroidal thickness and volume in diabetic retinopathy using optical coherence tomography and optical coherence tomography angiography; correlation with vision and foveal avascular zone

BackgroundTo represent choroidal thickness (CT) and choroidal volume (CV) databases in diabetic retinopathy (DR) patients and healthy control participants using optical coherence tomography (OCT) and enhanced depth imaging OCT (EDI-OCT). No study had evaluated CT at all main stages of diabetic retinopathy in a single study.MethodsThe study included 176 eyes from 93 patients (39–80 years old; 42% females) who were divided into three groups based on DR severity and normal control group: 39 eyes no DR, 64 eyes NPDR, 33 eyes PDR, and 40 eyes normal control. The CT and CV were measured and statistically analyzed. Intra-observer and inter-observer coefficients of repeatability were calculated.ResultsSubfoveal CT showed persistent thinning from normal group (322.50 ± 69.24) to no-diabetic retinopathy (NDR, 308.33 ± 74.45) to nonproliferative diabetic retinopathy (NPDR, 283.45 ± 56.50) group and then thickening as the patient progressed to proliferative diabetic retinopathy (PDR, 295.17 ± 95.69) (P = 0.087). A significant difference was found between the control group and the NDR, NPDR, and PDR groups in nearly all CT and CV of Early Treatment Diabetic Retinopathy Study macular subfields. Fasting blood sugar (FBS = 189.08 ± 51.3 mg/dl) and diabetes mellitus (DM) duration (13.6 ± 6.5 years) had no noticeable effect on CT. In patients with diabetes, the best-corrected visual acuity (BCVA), diabetic macular edema (DME), and foveal avascular zone (FAZ) were not affected by CT and CV.ConclusionsThe choroidal thickness decreases from the early stages of diabetic retinopathy up to the NPDR stage, with a subsequent modest rise in CT during the PDR stage. There was no correlation between FBS, diabetes duration, BCVA, DME, and FAZ, and CT.

Comparison of parameter agreement for characterization of corneal subbasal nerve plexus in the whorl-like region and central cornea using in vivo confocal microscopy.

To compare the reliability of the whorl-like region with that of the central cornea for accurate assessment of corneal subbasal nerve plexus (SNP) by analyzing the parameter variability of these two anatomical regions in repeated measurements. Participants were scanned in the central cornea and whorl-like region with in vivo confocal microscopy on three occasions by two examiners within a time span of one week. Coefficients of repeatability (CoR), intra-class correlation coefficient (ICC), and Bland-Altman scatter plots with 95% limits of agreement (LOA) in the central cornea and whorl-like region were calculated, respectively, based on the nerve fiber length, then the inter-observer and intra-observer agreement were compared between these two anatomical regions. The inter-observer ICC was 0.945, the inter-observer CoR was 0.052, the intra-observer ICC was 0.936, and the inter-observer CoR was 0.046, with narrow 95% LOA within 1 standard deviation in the whorl-like region, whereas the inter-observer ICC was 0.600, the inter-observer CoR was 0.207, the intra-observer ICC was 0.206, and the intra-observer CoR was 0.253, with 95% LOA nearly threefold wider than the standard deviation in the central cornea. Nerve parameter in the whorl-like region showed higher inter-observer and intra-observer agreement than that of the central cornea. The whorl-like region is a more reliable site for accurate assessment of SNP.

Assessment of Bulbar Redness with a Newly Developed Keratograph

To determine the validity and reliability of the clinical assessment of bulbar redness (BR) using a newly developed corneal topographer. This is a cross-sectional diagnostic evaluation study. The BR scores [Oculus Index (OI)] from 30 eyes of 26 patients with different degrees of conjunctival hyperemia were assessed and scored automatically using a new method: a keratograph equipped with scanning and scoring software. The values obtained via this system were correlated with three image-based comparative subjective scales: the Institute for Eye Research (IER), the Efron, and the Validated Bulbar Redness (VBR) grading scales. The IER and Efron scores were interpolated to 0.1 unit, and the VBR scores were interpolated to 1 unit. We also evaluated the repeatability of each method and the level of agreement between the OI score and the scores achieved using the three other image-based methods. There was a significant correlation between the OI score and the scores obtained with the IER (r = 0.921, p < 0.001), Efron (r = 0.958, p < 0.001), and VBR (r = 0.965, p < 0.001) scales. The intraobserver intraclass correlation coefficients were 0.947, 0.874, 0.810, and 0.920 for the OI, IER, Efron, and VBR, respectively, and the intraobserver coefficients of repeatability were 13.924, 16.111, 17.684, and 16.900, respectively. Furthermore, the interobserver intraclass correlation coefficients were 0.889, 0.880, 0.884, and 0.881 for the OI, IER, Efron, and VBR, respectively, and the interobserver coefficients of repeatability were 15.934, 16.366, 22.059, and 21.373, respectively. The OI is an objective and reliable method for scoring BR. Its reproducibility was the highest of all the four modalities. The keratograph is recommended, therefore, as a suitable alternative for BR assessment.

Abdominal Aortic Aneurysm Imaging with 3-D Ultrasound: 3-D-Based Maximum Diameter Measurement and Volume Quantification

The clinical reliability of 3-D ultrasound imaging (3-DUS) in quantification of abdominal aortic aneurysm (AAA) was evaluated. B-mode and 3-DUS images of AAAs were acquired for 42 patients. AAAs were segmented. A 3-D-based maximum diameter (Max3-D) and partial volume (Vol30) were defined and quantified. Comparisons between 2-D (Max2-D) and 3-D diameters and between orthogonal acquisitions were performed. Intra- and inter-observer reproducibility was evaluated. Intra- and inter-observer coefficients of repeatability (CRs) were less than 5.18 mm for Max3-D. Intra-observer and inter-observer CRs were respectively less than 6.16 and 8.71 mL for Vol30. The mean of normalized errors of Vol30 was around 7%. Correlation between Max2-D and Max3-D was 0.988 (p < 0.0001). Max3-D and Vol30 were not influenced by a probe rotation of 90°. Use of 3-DUS to quantify AAA is a new approach in clinical practice. The present study proposed and evaluated dedicated parameters. Their reproducibility makes the technique clinically reliable.

Variability of subfoveal choroidal thickness measurements in patients with age-related macular degeneration and central serous chorioretinopathy

To evaluate the variability in subfoveal choroidal thickness measurements in patients with age-related macular degeneration (AMD) and central serous chorioretinopathy using enhanced depth imaging optical coherence tomography (EDI-OCT). One hundred and sixty eyes of 160 patients who were diagnosed with early AMD (N=40), exudative AMD (N=40), polypoidal choroidal vasculopathy (PCV, N=40), or central serous chorioretinopathy (CSC, N=40) were included in this retrospective observational study. In addition, we included 40 normal eyes of 40 subjects. Subfoveal choroidal thickness was measured manually by two masked observers based on EDI-OCT images. The correlation of choroidal thickness with the absolute value of the difference in the choroidal thickness measurement was estimated for all 200 eyes. Intraobserver and interobserver coefficients of repeatability (CRs) were calculated. There was a significant positive correlation between subfoveal choroidal thickness and both intraobserver (P<0.001) and interobserver (P<0.001) difference in choroidal thickness measurements. The mean intraobserver CRs in nonexudative AMD, exudative AMD, PCV, CSC, and normal eyes were ~15-21, 23-29, 24-35, 32-38, and 19-25 μm, respectively. The mean interobserver CRs were ~24-28, 30-36, 39-45, 46-57, and 26-35 μm, respectively. Relatively great measurement variability should be considered when investigating eyes with pathologic conditions related to a thick choroid, including PCV or CSC.

MACULAR AND PERIPAPILLARY CHOROIDAL THICKNESS IN DIABETIC PATIENTS

To investigate macular and peripapillary choroidal thickness (CT) in diabetic patients with and without diabetic retinopathy (DR). One hundred and fifty subjects were enrolled: 102 diabetic patients (102 eyes) and 48 normals, as controls. Exclusion criteria were previously treated DR, refractive error higher than ± 3 diopters, and treated or untreated glaucoma. All patients underwent full ophthalmic examination, stereoscopic color fundus photography, and spectral domain optical coherence tomography (RS-3000; Nidek). Spectral domain optical coherence tomography examination consisted of linear scans, 6 mm in length, centered onto the fovea, and circle scan positioned around the optic disk (3.46 mm in diameter). Choroidal thickness was measured manually at the fovea and at 1, 2, and 3 mm distance along all scans in the macula. Peripapillary CT was measured at eight points along the circle scan. All measurements were performed independently by 2 masked graders. Mean age was not significantly different between patients with diabetes and controls. In the macular area, CT was significantly lower in the nasal quadrant versus all other quadrants (P < 0.0001), in both groups. In the peripapillary area, CT was significantly lower in the inferior quadrant versus all other quadrants (P < 0.05), in both groups. Mean macular and peripapillary CT progressively and significantly decreased with increasing level of DR (nonproliferative and proliferative DR vs. controls, P < 0.05). No significant CT difference was found between controls and diabetic eyes without detectable DR. Diabetic macular edema did not influence CT. Interobserver coefficient of repeatability was 28.8 (95% confidence interval, 24.8-32.8) for foveal measurements and 13.0 (95% confidence interval, 11.2-14.8) for peripapillary measurements. Pearson correlation coefficient was 0.99, and P <0.0001 for all measurements. Choroidal thickness is reduced in diabetic eyes and parallels appearance and evolution of DR. Spectral domain optical coherence tomography clearly confirms in vivo previously reported histopathologic observations. The role of choroid in the pathophysiology of DR needs to be adequately investigated.

Main bronchial diameters in patients with very severe COPD

This retrospective study was performed in order to determine if patients with very severe chronic obstructive pulmonary disease (COPD) have larger main bronchi than patients with less severe disease. Charts of patients having had a spirometric evaluation of their COPD and a digitized thin-slice computed tomography (CT) scan between January 2004 and September 2007 were reviewed. Adequate CT scans of male patients [i.e., those allowing a multiplane reconstruction (MPR) of the upper tracheobronchial tree using a double orthogonal oblique method] were divided into two groups: group 1 [forced expiratory volume in 1 s (FEV(1)) ranging from 30% to 80%] and group 2 (FEV(1) < 30%). Intraobserver and interobserver coefficients of repeatability were 1.79 and 2.51 mm, respectively. Median values and interquartile ranges of minimum right main bronchial diameter were 11.0 (9.6-12.7) mm versus 12.7 (10.8-13.9) mm in groups 1 (27 patients) and 2 (10 patients), respectively (P = 0.048); values for the minimum left main bronchial diameter were 10.7 (8.9-11.9) mm versus 11.8 (11.2-12.4) mm in groups 1 and 2, respectively (P = 0.040). The difference between the groups in median values of the minimum right and left main bronchial diameters was 1.2 mm. Other values were similar in both groups. The difference in minimum main bronchial diameters between our two groups corresponded to a difference of two or three sizes of a double-lumen tube. This difference must be taken into account for tube selection for such patients. Further studies are needed to prove that CT scan MPR can improve patients' intraoperative care.

A method for calcium quantification by means of CT coronary angiography using 64-multidetector CT: very high correlation with agatston and volume scores

To find out whether calcium scoring of the coronary arteries (CAC scoring) could be carried out with a CT angiography of the coronary arteries (CTCA) in a single CT data acquisition. The Agatston and V130 scores for 113 patients were assessed. A calcium volume score (V600 score) was compiled from the CTCA data sets. Intra- and interobserver correlations were excellent (rho > 0.97). The intra- and interobserver repeatability coefficients were extremely low, increasing in magnitude from the V600 score to the V130 and Agatston scores. The V600 score underestimates the coronary calcium burden. However, it has a linear relation to the Agatston and V130 scores. Thus, they are predictable from the values of the V600 score. The V600 score shows a linear relation to the classic CAC scores. Due to its extremely high reliability, the score may be a feasible alternative for classic CAC scoring methods in order to reduce radiation dosages.

Multidimensional Characterization of Carotid Artery Stenosis Using CT Imaging: A Comparison with Ultrasound Grading and Peak Flow Measurement

Purpose Clinical decision making for carotid surgery depends largely upon stenosis grade. While digital subtraction angiography remains the gold standard for stenosis grading, many physicians use less invasive modalities. The purpose of this study was to compare the results of multidimensional Computed tomography (CTA) with ultrasound (US) grading and peak flow velocity (PSV). Methods 37 stenosed carotid arteries were studied retrospectively in 36 consecutive patients. US grading and PSV were compared to multidimensional CTA analysis (diameter, area and volumetric measurements), performed by a medical software company. Calculations of stenosis percentage on CTA were made using the NASCET and ECST methodology. Diameter measurements were also performed by a neuroradiologist. Results All CTA diameter, area and volume measurements had only modest correlation with PSV ( r < 0.5) and ultrasound grading ( p < 0.5). There was concordant classification of stenosis grades in only 40–60% of cases. CTA diameter, area and volume measurements had good correlation (0.69 < r < 0.87) with one another using ECST methodology. Using NASCET methodology on CTA, correlation between diameter and area was insignificant ( r = 0.32). CTA volumetric analysis with the NASCET method yielded 27 negative stenosis grades. Repeatability coefficient for selecting the normal distal ICA 20 mm more distally was 20% for diameter and 43% for area. CTA diameter interobserver repeatability coefficients were 22.9% (NASCET) and 17.8% (ECST) and 0.7 mm (lumen) and 1.9 mm (vessel). Conclusions All CTA measurements showed moderate correlation with both ultrasound grading and PSV. Selection of the level of the normal distal ICA influences the NASCET calculations and can produce discrepant stenosis grades. Multidimensional CTA analysis seems to have no additional value for stenosis grading, but provides other useful anatomic information.

Comparison of manual and automated quantification methods of 123I-ADAM

123I-ADAM is a novel radioligand for imaging of the brain serotonin transporters (SERTs). Traditionally, the analysis of brain receptor studies has been based on observer-dependent manual region of interest definitions and visual interpretation. Our aim was to create a template for automated image registrations and volume of interest (VOI) quantifications and to show that an automated quantification method of 123I-ADAM is more repeatable than the manual method. A template and a predefined VOI map was created from 123I-ADAM scans done for healthy volunteers (n = 15). Scans of another group of healthy persons (HS, n = 12) and patients with bulimia nervosa (BN, n = 10) were automatically fitted to the template and specific binding ratios (SBRs) were calculated by using the VOI map. Manual VOI definitions were done for the HS and BN groups by both one and two observers. The repeatability of the automated method was evaluated by using the BN group. For the manual method, the interobserver coefficient of repeatability was 0.61 for the HS group and 1.00 for the BN group. The introobserver coefficient of repeatability for the BN group was 0.70. For the automated method, the coefficient of repeatability was 0.13 for SBRs in midbrain. An automated quantification gives valuable information in addition to visual interpretation decreasing also the total image handling time and giving clear advantages for research work. An automated method for analysing 123I-ADAM binding to the brain SERT gives repeatable results for fitting the studies to the template and for calculating SBRs, and could therefore replace manual methods.

Intra- and interobserver repeatability of radiographic measurements in hallux surgery

To test the hypothesis that the repro-ducibility of radiographic measurements of the first metatarsophalangeal angle and the intermetatarsal angle I-II can be increased by exact guidelines, we calculated the intra- and interobserver reliability of both methods. 4 independent observers (2 senior residents and 2 orthopedic trainees) evaluated 50 pre- and 50 postoperative plain dorsoplantar radiographs with their method of preference and then with Mitchell et al.'s method (1958).The mean intraobserver coefficient of repeatability for the metatarsophalangeal angle improved from 5.9° to 4.2° and for the intermetatarsal angle I-II, from 4.4° to 2.8°. The interobserver coefficient of repeatability improved from 6.5° to 5.0° for the metatarsophalangeal angle, and from 4.9° to 3.6° for the intermetatarsal angle I-II. This improvement in measurement accuracy was more marked for postoperative measurements, due to deformation of the metatarsal after the osteotomy which made it more difficult to find the longitudinal axis of the metatarsal. The improvements in the accuracy of measurements were also greater in the two inexperienced observers, since their measurements differed more when they had no exact guidelines for their drawings.

Intra- and interobserver repeatability of radiographic measurements in hallux surgery: improvement and validation of a method.

To test the hypothesis that the reproducibility of radiographic measurements of the first metatarsophalangeal angle and the intermetatarsal angle I-II can be increased by exact guidelines, we calculated the intra- and interobserver reliability of both methods. 4 independent observers (2 senior residents and 2 orthopedic trainees) evaluated 50 pre- and 50 postoperative plain dorsoplantar radiographs with their method of preference and then with Mitchell et al.'s method (1958). The mean intraobserver coefficient of repeatability for the metatarsophalangeal angle improved from 5.9 degrees to 4.2 degrees and for the intermetatarsal angle I-II, from 4.4 degrees to 2.8 degrees. The interobserver coefficient of repeatability improved from 6.5 degrees to 5.0 degrees for the metatarsophalangeal angle, and from 4.9 degrees to 3.6 degrees for the intermetatarsal angle I-II. This improvement in measurement accuracy was more marked for postoperative measurements, due to deformation of the metatarsal after the osteotomy which made it more difficult to find the longitudinal axis of the metatarsal. The improvements in the accuracy of measurements were also greater in the two inexperienced observers, since their measurements differed more when they had no exact guidelines for their drawings.

Inter- and intraobserver variability of CT measurements obtained after endovascular repair of abdominal aortic aneurysms.

Important decisions are made on the basis of CT angiographic measurements of aneurysm size obtained after endovascular abdominal aortic aneurysm repair; however, little is known about the variability of these measurements. We evaluated the variability of CT angiographic measurements of aneurysm size obtained after endovascular abdominal aortic aneurysm repair. Thirty CT angiographic data sets were randomly chosen from 91 sets, including preoperative, postoperative, and follow-up CT images. All images were obtained according to a standardized acquisition protocol. On a workstation, three parameters were measured: maximum aneurysm diameter, maximum aneurysm cross-sectional area, and aneurysm volume. All data sets were measured twice by two investigators in a random order. The difference of each pair of measurements was plotted against the mean value. The mean difference and its standard deviation were calculated with a repeatability coefficient. The intraobserver repeatability coefficient for observer 1 was 3.8 mm for diameter, 201.7 mm(2) for cross-sectional area, and 5.6 mL for volume. For observer 2, these figures were 3.0 mm, 219.0 mm(2), and 8.1 mL, respectively. The interobserver repeatability coefficients were 3.9 mm, 236.2 mm(2), and 10.3 mL. Determination of the repeatability coefficient of aneurysm size measurements obtained after endovascular abdominal aortic aneurysm repair provides a good description of precision.

A New Ultrasonographic Method to Detect Disease Activity and Predict Response to immunosuppressive Treatment in Graves Ophthalmopathy

To determine whether the internal reflectivity of the eye muscles on A-mode ultrasonography serves as indicator for disease activity in Graves ophthalmopathy, thereby predicting response to immunosuppressive treatment. Eye muscle reflectivity, expressed as percentage of the initial scleral spike, was measured in the superior, medial, and lateral recti, and normal values were determined in 23 healthy controls. These were compared with values in 16 consecutive patients with untreated, moderately severe Graves ophthalmopathy. The accuracy of the measurement was assessed by calculating the intra- and interobserver coefficient of repeatability. Baseline eye muscle reflectivity in the 16 patients was correlated to the therapeutic outcome 24 weeks after start of immunosuppressive therapy. The response to treatment served as indicator for pretreatment disease activity. Eye muscle reflectivity could be measured reliably, with an intraobserver coefficient of repeatability of 8.2% in controls and 10.2% in patients. Patients had lower reflectivity than controls (54.6 +/- 17.4% versus 70.7 +/- 6.6%; P < 0.001). Reflectivity in eye muscles with the lowest echogenicity was lower in responders than in nonresponders (25.8 +/- 8.4% versus 40.6 +/- 13.6%; P = 0.02). From the individual data, a cut-off value of 40% was derived, which appeared as an accurate predictor of outcome (positive predictive value 73%; 95% confidence interval 39%-94%). Measuring eye muscle reflectivity in Graves ophthalmopathy appears to be a reliable new method to determine disease activity, with a promising accuracy in predicting therapeutic outcome of immunosuppressive treatment.