Interobserver Variability Of Measurements Research Articles

Interobserver Variability in Ultrasound-Based Liver Fat Quantification.

To assess interobserver variability in ultrasound-based quantitative liver fat content measurements and to determine how much time these quantitative ultrasound (QUS) techniques require. One hundred patients with known or suspected of having nonalcoholic fatty liver disease were included in this prospective study. Two observers who were blinded to each other measurements performed tissue attenuation imaging (TAI) and tissue scatter distribution imaging (TSI) techniques independently. Both observers assessed hepatic steatosis visually and obtained 5 measurements for each QUS technique and the median values of the measurements were recorded. Spearman's correlation test was used to assess the correlation between QUS measurements and visual hepatic stetaosis grades. Intraclass correlation coefficient (ICC) test was used to assess interobserver variability in QUS measurements. The median values of TAI measurements for the observers 1 and 2 were 0.75 and 0.74 dB/cm/MHz, respectively. The median values of TSI measurements for the observers 1 and 2 were 93.53 and 92.58, respectively. The interobserver agreement in TAI (ICC: 0.970) and TSI (ICC: 0.938) measurements were excellent. The mean of the required time period for TAI technique were 55.1 ± 7.8 and 59.9 ± 6.6 seconds for the observers 1 and 2, respectively. The mean of the required time period for TSI technique were 49.1 ± 5.8 and 54.1 ± 5.4 seconds for the observers 1 and 2, respectively. The current study revealed that both TAI and TSI techniques are highly reproducible and can be implemented into daily practice with little additional time requirement.

Skeletal Muscle Mass Measurement Using Cone-Beam Computed Tomography in Patients With Head and Neck Cancer.

Background and purposeHead and neck cancer (HNC) patients usually present with malnutrition during radiotherapy, leading to loss of skeletal muscle mass (SMM) and poor clinical outcomes. CT has been used in clinical practice for measuring SMM in cancer patients. However, its clinical application for monitoring SMM is limited by the expensive price and high radiation exposure. This study aimed to investigate the feasibility of cone-beam computed tomography (CBCT) for assessing SMM and its changes in HNC patients undergoing radiotherapy.Materials and methodsThis study was divided into two parts. In part 1 (n = 32), the cross-sectional of skeletal muscle area (SMA) at the third cervical vertebra (C3) based on CBCT and computed tomography (CT) was assessed. In part 2 (n = 30), CT and CBCT were performed, and patients’ weight was measured before and at four different time points during radiotherapy. SMAs at C3 were independently identified by three senior radiation oncologists. The interobserver agreement of SMA on CBCT (SMACBCT) findings was analyzed using the intraclass correlation coefficient (ICC). One-way analysis of variance was used to evaluate the interobserver variability and statistical significance for SMA measurements. CBCT and CT measurement differences and correlations were analyzed using paired sample t-test and Pearson correlation analysis, respectively. The Krouwer variant of the Bland–Altman plot was used to analyze the agreement of SMA measurements between CBCT and CT. A simple linear regression model was used to analyze the relationship of SMA measurements between the two imaging techniques, and the equation was established. A repeated-measures ANOVA was performed to evaluate the effects and interactions between weight loss, SMA loss, and time.ResultsSMACBCT demonstrated excellent interobserver reliability; no significant difference between SMACBCT and SMA on CT (SMACT) at C3 was observed in all patients. The SMACBCT and SMACT were highly correlated (r = 0.966; 95% confidence interval = 0.955–0.975; p < 0.001). Bland–Altman analysis revealed that SMACBCT was generally higher than SMACT. The predicted SMA value at C3 on CT using CBCT was similar to the actual value. Moreover, significant differences between SMA and weight loss (F =10.99, p = 0.002), groups (weight loss and SMA loss) and times (4 time points) (F = 3.93, p = 0.013), and mean percent loss over time (F = 7.618, p < 0.001) were noted.ConclusionCBCT may be used as an alternative for CT to measure SMA in HNC patients during radiotherapy.

Variability in Depth of Invasion Measurements in Carcinomas of the Oral Cavity and the Effect on Pathologic Tumor Staging.

Depth of invasion (DOI) was added to the staging criteria for carcinoma of the lip and oral cavity in the 8th edition of the American Joint Committee on Cancer Staging Manual (AJCC8). However, there are multiple practical challenges to obtaining an accurate DOI measurement with limited data regarding interobserver variability in DOI measurement. The aim of this study was to investigate interobserver variability in DOI measurement and its effect on tumor stage. We performed an electronic medical record search for excisions of squamous cell carcinoma of the oral cavity between January 1, 2010 and December 25, 2017. All slides containing significant tumor were selected for independent blinded DOI measurement by four head and neck pathologists per AJCC8 guidelines. Pathologic stage was assigned in conjunction with reported tumor greatest dimension. Observers recorded the slide used for measurement and potential issues limiting assessment of DOI. Results were compared for reproducibility in DOI and tumor stage using intraclass correlation coefficient (ICC) analysis. A total of 167 cases of oral squamous cell carcinoma with available slides were included. The ICC score for DOI between observers was 0.91339 (> 0.9 considered excellent). Only 7.2% of cases had uniform DOI amongst observers. Increasing overall tumor size and average DOI correlated with increasing range in DOI amongst observers. Differences in DOI resulted in differences in pathologic tumor staging (pT) for 15% of tumors. Use of different slides for DOI measurements was significantly associated with different pT staging. In contrast, ulceration and exophytic growth did not correlate with higher DOI or pT variability. Despite the excellent ICC score, differences in DOI measurement resulted in variable pT staging for a considerable number of cases. We therefore recommend consensus for DOI in at least some cases in which potential differences in DOI could alter pT stage assignment.

Exploring the Interobserver Agreement in Computer-Aided Radiologic Tumor Measurement and Evaluation of Tumor Response.

The accurate, objective, and reproducible evaluation of tumor response to therapy is indispensable in clinical trials. This study aimed at investigating the reliability and reproducibility of a computer-aided contouring (CAC) tool in tumor measurements and its impact on evaluation of tumor response in terms of RECIST 1.1 criteria. A total of 200 cancer patients were retrospectively collected in this study, which were randomly divided into two sets of 100 patients for experiential learning and testing. A total of 744 target lesions were identified by a senior radiologist in distinctive body parts, of which 278 lesions were in data set 1 (learning set) and 466 lesions were in data set 2 (testing set). Five image analysts were respectively instructed to measure lesion diameter using manual and CAC tools in data set 1 and subsequently tested in data set 2. The interobserver variability of tumor measurements was validated by using the coefficient of variance (CV), the Pearson correlation coefficient (PCC), and the interobserver correlation coefficient (ICC). We verified that the mean CV of manual measurement remained constant between the learning and testing data sets (0.33 vs. 0.32, p = 0.490), whereas it decreased for the CAC measurements after learning (0.24 vs. 0.19, p < 0.001). The interobserver measurements with good agreement (CV < 0.20) were 29.9% (manual) vs. 49.0% (CAC) in the learning set (p < 0.001) and 30.9% (manual) vs. 64.4% (CAC) in the testing set (p < 0.001). The mean PCCs were 0.56 ± 0.11 mm (manual) vs. 0.69 ± 0.10 mm (CAC) in the learning set (p = 0.013) and 0.73 ± 0.07 mm (manual) vs. 0.84 ± 0.03 mm (CAC) in the testing set (p < 0.001). ICCs were 0.633 (manual) vs. 0.698 (CAC) in the learning set (p < 0.001) and 0.716 (manual) vs. 0.824 (CAC) in the testing set (p < 0.001). The Fleiss’ kappa analysis revealed that the overall agreement was 58.7% (manual) vs. 58.9% (CAC) in the learning set and 62.9% (manual) vs. 74.5% (CAC) in the testing set. The 80% agreement of tumor response evaluation was 55.0% (manual) vs. 66.0% in the learning set and 60.6% (manual) vs. 79.7% (CAC) in the testing set. In conclusion, CAC can reduce the interobserver variability of radiological tumor measurements and thus improve the agreement of imaging evaluation of tumor response.

Comparison of volumetric and bidimensional measurement of the thymic gland to determine interobserver variability

Aim: Thymic measurements should be interpreted relative to normal measurement values according to age groups and gender. Thymic gland measurement may vary between radiologists. In our study we wanted to determine the interobserver variability of thymic size measurements on CT by comparing volumetric calculations to commonly used bidimensional measurements.&#x0D; Material and Method: The chest CT scans of 156 patients who had any oncological problems or disorders influencing the thymic size were retrospectively evaluated. The shape (quadrilateral or triangular), anteroposterior (AP) and transverse (TR) diameters, as well as the thickness of each lobe and thymus volume were measured independently by two radiologists. Interobserver variability was determined according to these parameters by Pearson correlation test.&#x0D; Results: The shape of the thymic gland was triangular in 72% (n:113) and quadrilateral in 28% (n: 43) of all subjects. According to the results of the correlation test, a moderate relationship in terms of AP length, a weak relationship in terms of TR length, a negligible relationship in terms of right lobe thickness and a weak relationship in terms of left lobe thickness were obtained, but a very strong relationship was found between the two radiologists for volumetric measurements.&#x0D; Conclusions: Volumetric measurements can be used as a basis for thymic imaging, reducing the differences among radiologists, and unnecessary and advanced examinations can be avoided.

Interobserver variability in MRI measurements of mesorectal invasion depth in rectal cancer.

To assess the interobserver variability in MRI measurements of mesorectal invasion depth (MID) in rectal adenocarcinomas primarily staged as T3, by determining the level of interobserver agreement in the differentiation of individual T3 substages and of T3a-b vs. T3c-d disease, between readers with different levels of expertise. A retrospective analysis of 60 patients classified by MRI as having T3 rectal cancers was performed. Each patient underwent MR examination in a 1.5T machine and the standard imaging protocol included a high-resolution axial T2-weighted sequence in which the measurements were determined by independent radiologists (readers A and B, with 15years and 1year of experience, respectively). The rectum was further divided into quadrants and each reader selected the quadrant where the measurement was taken. The patients were grouped according to the MID (T3a < 1mm; T3b 1-5mm; T3c > 5-15mm; T3d > 15mm) and the interobserver reliability was tested using Cohen's kappa. Population included 40 males and 20 females with a median age of 65.9years. Interobserver agreement on individual substage differentiation (T3 a, b, c and d) was moderate (K = 0.428) and in the quadrant evaluation the level of agreement was also moderate (K = 0.414). Nevertheless, the interobserver reliability for the differentiation between stages T3a-b vs. T3c-d was substantial (K = 0.697). There is no considerable interobserver variability when distinguishing T3a-b from T3c-d tumors, regardless of the quadrant where the MID is measured. Therefore, assessment of MID, for that purpose, is a reproducible MR parameter, irrespectively of the readers' experience.

Ovarian Cystadenomas: Growth Rate and Reliability of Imaging Measurements.

To evaluate the growth rate of benign ovarian cystadenomas and the degree of variability in ultrasound measurements. Two independent retrospective cohorts of women found to have benign cystadenomas at surgery were identified. To assess growth rate, ultrasounds on women in a community-based health system were reviewed and the growth rate was determined based on the maximum reported size dimension using a mixed effect model. To assess measurement variability, two radiologists independently measured presurgical adnexal imaging findings for women in a tertiary care referral setting. Interobserver, intra-observer, and intermodality (cine clip versus still images) variability in measurements was determined using correlation coefficients (CC) and Bland-Altman analysis, with the proportion of measurements varying by more than 1 cm calculated. For growth rate assessment, 405 women with 1412 ultrasound examinations were identified. The median growth rate was 0.65 cm/year with mucinous cystadenomas growing faster at 0.83 cm/year compared to 0.51 cm/year for serous cystadenomas (median test P < .0001). To evaluate measurement variability, 75 women were identified with 176 ultrasound studies. The within-subject standard deviations for ultrasound measurements were 0.74 cm for cine clip images and 0.41 cm for static images, with 11% of measurements overall differing by more than 1cm. Cystadenomas grow on average 0.65 cm/year, which is similar in magnitude to the inherent error observed in measurement on ultrasound, suggesting that repeat ultrasound at intervals of longer than a year will often be needed to accurately assess growth if a cyst represents a benign cystadenoma.

Intra- and Interobserver Variability in Magnetic Resonance Imaging Measurements in Rectal Cancer Patients.

Simple SummaryColorectal cancer is the second most common cancer and was the second most common cause of cancer-related death in Europe in 2018. Accurate lymph node staging in primary rectal cancer staging is essential for the selection of the proper treatment regimen. In 2018, The European Society of Gastrointestinal and Abdominal Radiology published consensus recommendations for primary rectal cancer staging, and suggested that lymph nodes be assessed by size, morphology, and location in- or outside the mesorectal fascia. Our study aimed to assess the inter- and intraobserver variability in size, apparent diffusion coefficient measurements, and morphological characterization among inexperienced and experienced radiologists. Our data indicate that subjective variables like morphological characteristics are less reproducible than numerical variables, regardless of the level of experience of the observers.Colorectal cancer is the second most common cancer in Europe, and accurate lymph node staging in rectal cancer patients is essential for the selection of their treatment. MRI lymph node staging is complex, and few studies have been published regarding its reproducibility. This study assesses the inter- and intraobserver variability in lymph node size, apparent diffusion coefficient (ADC) measurements, and morphological characterization among inexperienced and experienced radiologists. Four radiologists with different levels of experience in MRI rectal cancer staging analyzed 36 MRI scans of 36 patients with rectal adenocarcinoma. Inter- and intraobserver variation was calculated using interclass correlation coefficients and Cohens-kappa statistics, respectively. Inter- and intraobserver agreement for the length and width measurements was good to excellent, and for that of ADC it was fair to good. Interobserver agreement for the assessment of irregular border was moderate, heterogeneous signal was fair, round shape was fair to moderate, and extramesorectal lymph node location was moderate to almost perfect. Intraobserver agreement for the assessment of irregular border was fair to substantial, heterogeneous signal was fair to moderate, round shape was fair to moderate, and extramesorectal lymph node location was substantial to almost perfect. Our data indicate that subjective variables such as morphological characteristics are less reproducible than numerical variables, regardless of the level of experience of the observers.

Canine anal sac gland carcinoma with regional lymph node metastases treated with sacculectomy and lymphadenectomy: Outcome and possible prognostic factors.

The staging system commonly used in canine anal sac gland carcinoma (ASGC) is a revised Tumour-Node-Metastasis (TNM) system published in 2007. This staging system consists in four stages and, for dogs with nodal metastases, the size of the metastatic lymph node (mLN) defines the N stage. However, we hypothesise that (1) the mLN size has no prognostic significance when the mLN can be excised, (2) a high number of mLNs is associated with poorer prognosis and (3) the measurement of the mLN on imaging is not reproducible. To investigate these hypotheses, medical records and diagnostic images of dogs with ASGC and mLN, treated with sacculectomy and lymphadenectomy, with or without chemotherapy, were reviewed. Interobserver variability for mLN measurement was assessed. Prognostic factors including mLN size and number were investigated. Time to documented progression (TDP) and disease-specific survival (DSS) were evaluated. Progression-free interval (PFI) was analysed with interval-censored data analysis. Fifty-seven dogs were included. The median PFI, TDP and DSS were 110 (95%CI 61.5-185.5), 196 (95%CI 162-283) and 340 days (95%CI 321-471), respectively. For measurement of the largest mLN, interobserver agreement was excellent but limits of agreement reached 39.7%. Neither the size of the largest mLN nor the use of adjuvant chemotherapy were associated with outcome. The number of mLNs was associated with outcome and having more than four mLNs was associated with shorter PFI (p< .001), TDP (p= .004) and DSS (p< .001). While mLN size measurement was not consistently reproducible and did not influence outcome in our cohort, number of mLNs did. Further studies are required for development of a revised staging system.

Interobserver variability of ultrasound measurements for the differential diagnosis of uterine prolapse and cervical elongation without uterine prolapse

ObjectivesOur study aims to determine the interobserver variability of different ultrasound measurements (pubis-cervix distance, pubis-uterine fundus distance, and pubis-Douglascul-de-sac distance) previously analyzed for the ultrasound differential diagnosis of uterine prolapse (UP) and cervical elongation CE without UP.Materials and methodsWe conducted a prospective observational study with 40 patients scheduled to undergo surgical correction of UP and CE without UP. All patients underwent pelvic floor ultrasound examination by an examiner (E1) who acquired ultrasound images. Using these images, E1 measured the distances for the ultrasound differential diagnosis of UP and CE without UP, and these distances were compared with those measured by the other examiner (E2). Values were analyzed by calculating ICCs with 95% CIs.ResultsFor UP, excellent reliability was obtained for all measurements except the pubis-Douglascul-de-sac measurement at rest, which was moderate (ICC 0.596; p = 0.028) and for the difference between the pubis-Douglascul-de-sac measurement at rest and during the Valsalva maneuver, which was good (ICC 0.691; p < 0.0005). For CE without UP, interobserver reliability was excellent for all measurements analyzed except the pubis-cervix measurement during the Valsalva maneuver, which was moderate (ICC 0.535; p = 0.052) and for the pubis-Douglascul-de-sac measurement at rest, which was good (ICC 0.768; p < 0.0005).ConclusionsThere is excellent interobserver reliability in measurements of the difference in the distance from the pubic symphysis to the uterine fundus at rest and during the Valsalva maneuver for both UP and CE without UP, which are used for the ultrasound differential diagnosis of UP and CE without UP.

OP08.03: Intra‐ and interobserver variability of sonographic measurements of endometriotic nodules within the rectosigmoid colon

OP08.03: Intra‐ and interobserver variability of sonographic measurements of endometriotic nodules within the rectosigmoid colon

Ventricular size measurement methods in fetuses considered for prenatal closure of myelomeningocele.

Prenatal closure of myelomeningocele is associated with a reduced rate of hydrocephalus treatment. This need for hydrocephalus treatment is positively correlated with fetal ventricular width. When ventricular width is 15 mm or greater, the benefits of prenatal closure, as a method to decrease hydrocephalus treatment, are reduced. Thus, fetal ventricular size is an important factor when counseling families who are considering intrauterine surgery with mitigation of hydrocephalus as the primary goal. This study sought to determine whether imaging modality (ultrasound [US] vs MRI) and interobserver variability were factors in any ventricular size disparity seen on imaging studies. The imaging studies of 15 consecutive fetuses who underwent prenatal myelomeningocele repair at Children's Mercy Fetal Health Center, Kansas City, Missouri, were reviewed. All fetuses were imaged with US and fetal MRI; on average (range), procedures were performed 3.8 (0-20) days apart. Three comparisons were performed to analyze interobserver and intermodality variability in ventricular width measurements: 1) retrospective comparison of dictated ventricular widths measured with MRI and US by pediatric radiologists (PRs) and maternal-fetal medicine specialists (MFMs), respectively; 2) blinded measurements obtained with US by PRs versus initial US-based measurements by MFMs, and blinded measurements obtained with MRI by PRs versus initial MRI-based measurements by PRs; and 3) blinded measurements obtained with MRI by PRs versus those obtained with US. Retrospective comparison showed that measurements with MRI by PRs were on average 2.06 mm (95% CI 1.43-2.69, p < 0.001) larger than measurements with US by MFMs. Blinded measurements with US by PRs were on average larger than dictated measurements obtained with US by MFMs, but by only 0.6 mm (95% CI 0.31-0.84, p < 0.001). When PRs measured ventricular size in a blinded fashion with both US and MRI, the mean width determined with MRI was significantly larger by 2.0 mm (95% CI 1.26-2.67, p < 0.0001). The ventricular width of these fetuses was larger when measured with MRI than US by an amount that could impact recommendations for fetal surgery. Every center involved in counseling families about the risks and benefits of fetal intervention for spina bifida needs to be aware of these possible imaging-based disparities.

Repeatability of PDA diameter measurements on echocardiography.

Diameter of the patent ductus arteriosus (PDA) on transthoracic echocardiography (TTE) is used as a marker of haemodynamic significance. We aimed to assess the intra- and inter-observer variability in PDA diameter in babies born at ≤ 30weeks' gestation. TTEs for 56 infants were performed by a single neonatologist. Cineloops were stored without measurement annotations. PDAs were measured on 2-dimensional (2D) and Colour Doppler. A second, blinded neonatologist repeated measurements on the same cineloops. The scanning neonatologist repeated measurements at a later date, blinded to original measurements. Inter-observer results showed repeatability coefficients of 1.57 (2D) and 2.18 (Colour), and repeatability index of 73% (2D) and 91% (Colour). Intra-observer results showed repeatability coefficients of 0.99 (2D) and 1.32 (Colour), and repeatability index of 43% (2D) and 49% (Colour).Conclusion: There is significant inter- and intra-observer variability in measurements of PDA diameter, even on the same cineloops. We advise caution when using diameter alone as a marker of haemodynamic significance, and recommend using multiple parameters to determine haemodynamic significance of PDA. What is Known: • PDA is associated with numerous comorbidities such as bronchopulmonary dysplasia, necrotising enterocolitis, intraventricular haemorrhage and mortality. • PDA diameter is commonly measured on transthoracic echocardiography and used as a marker of haemodynamic significance. • A previous, smaller study has shown there may be poor repeatability of PDA diameter measurements in serial echocardiograms. What is New: • There is significant inter-observer variability in 2D and Colour Doppler measurements of PDA internal diameter on TTE in preterm infants. • There is moderate intra-observer correlation of repeated measurements on the same imaging in both 2D and Colour Doppler imaging.

Sonographic Assessment of Renal Volume in Normotensive Pregnant Women and Women With Pregnancy-Induced Hypertension in Enugu Metropolis

Objective: Renal volume (RV) assessment during obstetric sonography is rarely considered in our locality. Understanding the changes in RV in both normotensive pregnant (NP) and pregnancy-induced hypertensive (PIH) women is important in making correct diagnosis regarding pregnancy outcome. This study is aimed at determining the RV in NP and PIH women and correlating RV with fetal gestational age (FGA), body mass index (BMI), and parity in NP women. Materials and Methods: This cross-sectional study involved 450 patients recruited at a Tertiary Hospital. A pilot study was done to determine the interobserver variability in RV measurement. RV was calculated using the following formula: L × W × AP × 0.523. Parity, BMI, and blood pressure were documented, while FGA was calculated as an average of FGAs obtained from the measurements of fetal biometric parameters. Results: Mean RV of PIH women was significantly higher than that of NP women ( P &lt; .05). RV shows a positive significant relationship with BMI and FGA, while it shows a negative relationship with parity in NP ( P &lt; .05). Conclusion: Reference range values of RV were generated for clinical use in our locality, while there is statistically significant difference between RV in NP and PIH women.

Comparison of three two-dimensional echocardiographic methods of assessing left ventricular size in Doberman Pinschers

IntroductionCompare three methods of obtaining linear left ventricular dimensions within the same Doberman Pinscher (DP). AnimalsOne hundred and thirty-nine client-owned DP. Materials and MethodsLinear left ventricular dimensions were measured using two-dimensional short-axis (Sx-2D), motion-mode short-axis (Sx-MM), and motion-mode long-axis (Lx-MM) methods, then left ventricular volumes were obtained using monoplane Simpson's method of discs (SMOD). A Friedman test with Dunn's multiple comparisons was used to compare differences between methods. Bias and correlation were evaluated via Bland-Altman and Spearman's correlation. Sensitivity and specificity for diagnosing occult dilated cardiomyopathy (DCM) compared to SMOD were determined. Coefficients of variation (CVs) were calculated for intra- and inter-observer measurement variability. ResultsThere were significant differences between all linear dimensions in diastole and systole. Short-axis 2D measurements had significant bias compared with Sx-MM (diastole +1.19 mm, systole +1.65 mm) and Lx-MM (diastole +4.36 mm, systole +3.87 mm) as did Sx-MM compared with Lx-MM (diastole +3.17 mm, systole +2.22 mm). All linear dimensions had a moderate positive correlation with SMOD. The sensitivity and specificity of linear measurements to detect DCM were: Sx-2D (sensitivity 72.0%, specificity 88.5%), Sx-MM (sensitivity 52.0%, specificity 92.0%), and Lx-MM (sensitivity 37.5%, specificity 99.1%). All methods had acceptably low CV for intra- and inter-observer measurement variability. ConclusionsResults of this study suggest that linear measurements are repeatable and correlate with reference standard; however, there is a significant bias between measurements, and they should not be used interchangeably.

Three-Dimensional Sonographic Evaluation of the Position of the Fetal Conus Medullaris at First Trimester

Objective: The objective of this study was to assess the position of the conus medullaris (CM) at the first trimester 3D ultrasound in a cohort of structurally normal fetuses. Methods: This was a multicenter prospective study involving a consecutive series of structurally normal fetuses between 11 and 13 weeks of gestation (CRL between 45 and 84 mm). All fetuses were submitted to 3D transvaginal ultrasound using a sagittal view of the spine as the starting plane of acquisition. At offline analysis, the position of the CM was evaluated by 2 independent operators with a quantitative and a qualitative method: (1) the distance between the most caudal part of the CM and the distal end of the coccyx (CMCd) was measured; (2) a line perpendicular to the fetal spine joining the tip of the CM to the anterior abdominal wall was traced to determine the level of this line in relation to the umbilical cord insertion (conus to abdomen line, CAL). Interobserver agreement for the CCMd was evaluated. Linear regression analysis was used to determine the association between the CMCd and CRL, and a normal range was computed based on the best-fit model. The absence of congenital anomalies was confirmed in all cases after birth. Results: In the study period between December 2019 and March 2020, 143 fetuses were recruited. In 130 fetuses (90.9%), the visualization of the CM was feasible. The mean value of the CMCd was 1.09 ± 0.16 cm. The 95% limits of agreement for the interobserver variability in measurement of the CMCd were 0.24 and 0.26 cm. The interobserver variability based on the intra-class correlation coefficient (ICC) for the CCMd was good (ICC = 0.81). We found a positive linear relationship between the CCMd and CRL. In all these fetuses, the CAL encountered the abdominal wall at or above the level of the cord insertion. Conclusion: In normal fetuses, the assessment of the CM position is feasible at the first trimester 3D ultrasound with a good interobserver agreement. The CM level was never found below the fetal umbilical cord insertion, while the CMCd was noted to increase according to the gestational age, confirming the “ascension” of the CM during fetal life.

Inter-observer and Inter-vendor Variability in Strain Measurements in Patients with Single Right Ventricular Anatomy.

Myocardial strain offers new insights into ventricular performance, There are software packages from several different companies used to ascertain this, and little data is available in patients with single right ventricle (sRV) physiology. We aimed to compare the analysis of two strain software applications using a cohort of patients with sRV for both inter-vendor and inter-observer variability. Echocardiograms from 85 patients with sRV (122 separate studies) were prospectively evaluated. All had Glenn and/or Fontan palliation. Longitudinal 4-chamber (4LS), inflow/outflow (IO), circumferential, and radial strain were assessed using Velocity Vector Imaging (VVI, Seimens, Munich) and Automated Functional Imaging (AFI, General Electric, Boston) software. In a subset of 45 patients (61 separate studies), strain measurements were obtained by two sonographers so a paired "inter-observer" analysis could be performed. A moderate correlation between measurements made by the two systems was observed. Circumferential strain assessment had the highest R value (0.77) with all others having R values < 0.6. Both software packages showed modest inter-observer reproducibility for longitudinal and circumferential strain. VVI intraclass correlation coefficients (ICC) for 4LS and average circumferential strain (ACS) were 0.6 and 0.58, compared to 0.68 and 0.59 for AFI. Other than radial strain and VVI IO inferior strain, mean strain differences between AFI and VVI were ≤ 1%. Inter-observer variability is modest, however, mean differences are minimal suggesting reasonable clinical reliability. Inter-vendor variability is greater and not as clinically reliable. In patients with sRV, serial assessments with strain should be performed using the same software.

Interobserver reliability of canine urine specific gravity assessed by analog or digital refractometers.

Refractometry is utilized routinely to evaluate canine urine specific gravity (USG) in veterinary clinical settings. We aimed to determine if the magnitude of interobserver reliability when assessing canine USG via refractometry could impact clinical judgment. USG was determined in 38 dogs by 3 registered veterinary technicians (RVTs) using both an optical analog refractometer and a digital refractometer. Summary statistics were reported, interobserver reliability was assessed via intraclass correlation coefficient (ICC) analysis through a 2-way mixed-effects model, and agreement between RVT pairs was compared through Bland-Altman plots. The median analog refractometer USG measurement was 1.018 (range: 1.004-1.040) and for the digital refractometer was 1.0176 (1.0035-1.0357). The analog refractometer average measure ICC was 0.995 (95% CI: 0.992, 0.997; p < 0.001). The digital refractometer average measure ICC was 0.999 (95% CI: 0.999, 1.000; p < 0.001). Strong agreement between all pairs of RVTs was seen via Bland-Altman plots for both analog and digital refractometers, with 95% CIs spanning no more than 0.002 in either the positive or negative direction for all pairings. The interobserver variability in canine USG measurements by RVTs was trivial and did not impact clinical judgment and decision-making.

Intra- and Inter-Observer Variability in Sonographic Measurement of the Cervical Nerve Roots of Healthy Volunteers

Aim: The aim of our study is to determine the normal values of mean cervical (C) nerve root diameter in millimeters (mm) in healthy volunteers and to show its relationship to age, gender, height, weight, body mass index (BMI), and the dominant hand.Material and Method: Two observers measured the mean nerve root diameter of the bilateral C5, C6, and C7 nerve of all volunteers. Before the procedure, the age, sex, height, weight, BMI, and the dominant hand of all the participants were noted. Two measurements were taken by each of the two observers without one knowing about the other’s noted values. The intraclass correlation coefficient (ICC) test was used to analyze intra-and inter-observer reliability.Results: There was no statistically significant relationship between gender and dominant hand, and mean nerve root diameter. Moreover, when we compared the mean nerve root diameter for the nerves in the right and left sides of each participant, no significant statistical differences were identified. The mean diameter of the C6 nerve root was higher than that of C7, which was higher than that of C5 on both sides (p &amp;lt; 0.001). The ICC values for intra- and inter-observer were good or excellent for all diameter measurements (ICC &amp;gt; 0.8).Conclusions: The normal range of cervical nerve root diameters should be determined to distinguish pathological conditions. In our study, the measurement of mean nerve root diameters of C5, C6, and C7 nerves is highly reproducible with excellent intra-observer and inter-observer agreement. Therefore, the measurement of nerve root diameter can be confidently performed in daily clinical practice.

DIPG-49. BRAINSTEM AND PONTINE VOLUMETRIC ANALYSIS AS A SURROGATE MEASURE OF LOCAL DISEASE CONTROL IN CHILDREN WITH DIFFUSE INTRINSIC PONTINE GLIOMA (DIPG)

INTRODUCTIONResponse-assessment in pediatric neuro-oncology (RAPNO) criteria designed to describe treatment outcomes are poorly implemented in diffuse intrinsic pontine glioma (DIPG), due to inter-observer variability in measurement of tumor volume, lack of tumor enhancement, and undefined relationships between radiographic parameters and survival. Given these issues, this study assessed whether anatomically defined brainstem and pontine volumes can serve as surrogate measures of local disease burden and response to therapy in DIPG.METHODSThirty-two consecutive patients with newly diagnosed DIPG were treated with standard definitive radiation therapy (RT) between 2010 and 2016 at a single institution. MRI brain scans throughout treatment course were analyzed using iPlan® Flow software (Brainlab AG, Munich, Germany). Semi-automated 3D measurements of the brainstem and pons were calculated using a built-in knowledge-based segmentation approach and manually adjusted.RESULTSMean age at diagnosis was 6.5+/-0.5 years (range 2–12 years). Median follow up time was 317 days. Average brainstem volume at diagnosis (Vdiag) was 52.7+/-2.1mL with subsequent decrease at first post-RT MRI to 41.4+/-2.0mL (p < 0.0001). By time of last follow up, brainstem volume increased to 51.9+/-3.3, no longer significantly different as compared to Vdiag (p=0.61). The same relationships were found for pontine volume.CONCLUSIONSVolumetric changes in the brainstem and pons occur in response to treatment and correlate with local disease burden and response to therapy. This surrogate may be a useful standardized measure in ongoing and future trials involving localized delivery of therapeutics in DIPG that require evaluation of local-regional disease control in addition to survival.