The image obtained by static ultrasonography (US), despite being a validated measure to identify muscle thickness (MT), has a visualization capacity limited by the size of the transducer. The extended field of view (EFOV) is a more recent technique of obtaining muscle images by the US, which allows observing MT over the entire length of the muscle. The purpose of the study was to determine the reliability and the intra- and inter-rater error of the MT measurement in the proximal, medial and distal portions of the vastus lateralis using the EFOV US. Twenty-five men (age = 24 ± 4 years) paid a visit to the laboratory. Two independent US technicians identified the anatomical landmarks and collected the images using EFOV US, with a 4 cm linear transducer, 10 MHz frequency and 6 cm image depth. After all collections, a third researcher codified the images, which were sent to two independent image raters. After a week, the images were shuffled, recoded and sent back to the same evaluators. The values ​​of the typical error of the measurement, coefficient of variation and intraclass correlation coefficient intra and inter-rater ranged between 0.01 and 0.03 cm, 0.47 and 2.32%, 0.990 and 0.998, respectively, for the two evaluators. The Bland-Altman analysis indicated high agreement and homoscedastic error of all comparisons. The high reliability and low errors observed, less than the increments typically found in training studies, reveal the great potential for EFOV US to determine MT in different portions of the vastus lateralis muscle.

Extended-field-of-view ultrasonography is a valid alternative to determine the dimensions of the skeletal striated muscle; however, some factors may influence the final measurement. The aim of this study was to determine the test-retest reliability and measurement error of vastus lateralis muscle architecture variables through internal anatomical landmarks and to compare three fixed determined points using extended-field-of-view ultrasonography. Twelve young (24 ± 6 years) adult university male students participated in the study. Images were obtained through extended-field-of-view ultrasonography of the vastus lateralis muscle. Measurements were made for muscle thickness (MT), fascicle length (FL), and fascicle pennation angle (FA) using a method that identifies internal anatomical landmarks. MT was also measured at predetermined distances of 2 cm proximal, 6 cm proximal, and 2 cm distal. One-way ANOVA with repeated measures did not identify any test-retest significant differences for all variables measured. Typical measurement error in centimeters (cm) or degrees (º), coefficient of variation in percentage (%) and intraclass correlation coefficient were MT = 0.07 cm, 2.93%, 0.964; FL = 0.31 cm, 2.89%, 0.947; FA = 0.92°, 4.08%, 0.942; MT 2 cm proximal = 0.10 cm, 3.77%, 0.910; MT 6 cm proximal = 0.27 cm, 9.66%, 0.576; MT 2 cm distal = 0.35 cm, 19.76%, 0.564. MT, FL and FA showed high reliability and low measurement error. Internal anatomical landmarks proved to be more reliable and presented smaller measurement errors when compared to the predetermined distances method.

Introdução: A ultrassonografia no modo B é limitada ao tamanho do transdutor, entretanto a técnica panorâmica permite mensurar o comprimento do fascículo sem a necessidade de utilizar equações de predição. Objetivo: Comparar o comprimento do fascículo do vasto lateral obtido pela ultrassonografia panorâmica e estimado por equações trigonométricas. Métodos: Participaram do estudo 15 homens com idades de 24 ± 6 anos. A pesquisa caracteriza-se como um estudo observacional comparativo de visita única. Foi realizada uma imagem de ultrassonografia panorâmica do vasto lateral através de um transdutor linear de 4 cm, com frequência de 10 MHz e 6 cm de profundidade de imagem, através de uma varredura de 13 cm. Após a coleta das imagens, foi comparado o comprimento do fascículo panorâmico e estimado por duas equações de predição diferentes. Resultados: A ANOVA de uma via não detectou diferença significativa (P = 0,093). As análises de diferença percentual, coeficiente de determinação, erro padrão da estimativa e coeficiente de correlação de Pearson entre a diferença e a média da medida panorâmica em comparação a equação 1 (Δ = 24,1%; R2 = 0,68; EPE = 0,9 cm; r = 0,796; p = 0,000) e equação 2 (Δ = 17,4%; R2 = 0,48; EPE = 1,1 cm; r = 0,695; p = 0,004) indicaram viés de proporção. Conclusão: Apesar de não ter sido observada diferença significativa entre as equações de predição e a medida panorâmica, as equações trigonométricas apresentaram uma superestimativa do comprimento do fascículo e uma baixa concordância com a medida de referência.