ABSTRACT
ABSTRACT BACKGROUND: Investigation of alterations to retinal microvasculature may contribute towards understanding the role of such changes in the pathophysiology of several chronic non-communicable diseases. The objective here was to evaluate the validity and reproducibility of retinal arteriole and venule diameter measurements made by Brazilian Longitudinal Study of Adult Health (ELSA-Brasil) graders. DESIGN AND SETTING: Cross-sectional study at six teaching and research institutions. METHODS: To evaluate validity, each of 25 retinal images from the University of Wisconsin (gold standard) was measured by five ELSA-Brasil graders. To evaluate reproducibility, 105 images across the spectrum of vessel diameters were selected from 12,257 retinal images that had been obtained between 2010 and 2012, and each image was reexamined by the same grader and by an independent grader. All measurements were made using the Interactive Vessel Analysis (IVAN) software. Bland-Altman plots, paired t tests and intraclass correlation coefficients (ICCs) were analyzed. RESULTS: Mean differences between ELSA-Brasil and gold-standard readings were 0.16 µm (95% CI -0.17-0.50; P = 0.31) for central retinal artery equivalent (CRAE), -0.21 µm (95% CI -0.56-0.14; P = 0.22) for central retinal vein equivalent (CRVE) and 0.0005 (95% CI -0.008-0.009; P = 0.55) for arteriole/venule ratio (AVR). Intragrader ICCs were 0.77 (95% CI 0.67-0.86) for CRAE, 0.90 (95% CI 0.780.96) for CRVE and 0.70 (0.55-0.83) for AVR. Intergrader ICCs were 0.75 (95% CI 0.64-0.85) for CRAE, 0.90 (95% CI 0.79-0.96) for CRVE and 0.68 (95% CI 0.55-0.82) for AVR. CONCLUSIONS: Retinal microvascular diameter measurements are valid and present moderate to high intra and intergrader reproducibility in ELSA-Brasil.
Subject(s)
Humans , Male , Female , Adult , Middle Aged , Aged , Arterioles/anatomy & histology , Retinal Vessels/anatomy & histology , Venules/anatomy & histology , Image Interpretation, Computer-Assisted , Socioeconomic Factors , Cross-Sectional Studies , Reproducibility of Results , Longitudinal StudiesABSTRACT
Background: Echocardiography, though non-invasive and having relatively low-cost, presents issues of variability which can limit its use in epidemiological studies. Objective: To evaluate left ventricular mass reproducibility when assessed at acquisition (online) compared to when assessed at a reading center after electronic transmission (offline) and also when assessed by different readers at the reading center. Methods: Echocardiographers from the 6 ELSA-Brasil study investigation centers measured the left ventricular mass online during the acquisition from 124 studies before transmitting to the reading center, where studies were read according to the study protocol. Half of these studies were blindly read by a second reader in the reading center. Results: From the 124 echocardiograms, 5 (4%) were considered not measurable. Among the remaining 119, 72 (61%) were women, mean age was 50.2 ± 7.0 years and 2 had structural myocardial abnormalities. Images were considered to be optimal/ good by the reading center for 110 (92.4%) cases. No significant difference existed between online and offline measurements (1,29 g, CI 95% −3.60-6.19), and the intraclass correlation coefficient between them was 0.79 (CI 95% 0.71-0.85). For images read by two readers, the intraclass correlation coefficient was 0.86 (CI 95% 0.78-0.91). Conclusion: There were no significant drifts between online and offline left ventricular mass measurements, and reproducibility was similar to that described in previous studies. Central quantitative assessment of echocardiographic studies in reading centers, as performed in the ELSA-Brasil study, is feasible and useful in clinical and epidemiological studies performed in our setting. .
Fundamento: A ecocardiografia, apesar de não invasiva e de relativo baixo custo, tem na variabilidade de medidas repetidas um dos principais limitantes a sua utilização em estudos epidemiológicos. Objetivo: Avaliar a reprodutibilidade da massa ventricular esquerda obtida em centros de investigação (on-line) com aquela obtida em centro de leitura (off-line) e entre medidas realizadas por diferentes avaliadores no centro de leitura. Métodos: Ecocardiografistas dos seis centros de investigação do ELSA-Brasil mediram on-line a massa ventricular esquerda e outras medidas ecocardiográficas de 124 exames antes de enviá-los ao centro de leitura, onde foram lidos off-line de acordo com o protocolo do estudo. Metade desses exames foi medida de forma cega por um segundo leitor. Resultados: Dos 124 exames, cinco (4%) foram considerados não mensuráveis. Dos 119 restantes, 72 (61%) eram de mulheres, com idade média de 50,2 ± 7,0 anos, sendo apenas dois exames com alteração estrutural cardíaca. Em 110 (92,4%) dos exames, as imagens foram consideradas ótimas/boas pelo centro de leitura. Não foram observadas diferenças significativas entre as médias da massa ventricular esquerda obtidas on-line e off-line (1,29 g, IC 95% −3,60-6,19), sendo o coeficiente de correlação intraclasse de 0,79 (IC 95% 0,72-0,85). Para as medidas realizadas no centro de leitura, % 0,78-0,91). Conclusão: Não houve diferenças sistemáticas relevantes na medida da massa ventricular esquerda on-line versus off-line e a reprodutibilidade das medidas foi similar à de estudos anteriores. A realização das medidas em centros de leitura, como utilizado no ELSA-Brasil, é factível e útil em estudos clínico-epidemiológicos realizados em nosso meio. .