Superficial and deep lumbar multifidus layers of asymptomatic individuals: intraday and interday reliability of the echo intensity measurement.

INTRODUCTION: Ultrasonography has been used to understand the functional and biomechanical aspects of the lumbar multifidus muscle in vivo. To characterize the multifidus echogenicity, the peculiarities of their superficial and deep layers must be considered. PURPOSE: The present paper aimed to characterize the lumbar multifidus echo intensity (EI), in both superficial and deep layers, in ultrasonography images acquired in longitudinal and transversal orientations. METHODS: Evaluator obtained two images in each side of the lumbar of the volunteer, who was lying on prone position. Ultrasonography images were taken with probe in transversal and longitudinal orientations. EI was estimated by means average value of the grayscale distribution histogram, by extracting from region of interest of the superficial and deep layer. All participants returned for a second test day. Two-way MANOVA test was applied to compare EI measurements, considering layers and side factors. The reliability and variability were analyzed by the intraclass correlation coefficient and standard error measurements (SEM), respectively. Two-way MANOVA found significant difference between the layers in the transversal and longitudinal images, but not between the sides. RESULTS: Interdays reliability ranged of reasonable to excellent, and SEM values were lower than 17.08%. The superficial layer of the multifidus muscle showed higher EI values than the deeper one. CONCLUSIONS: These analyses can serve as a basis for future studies approaching multifidus of the people with low back pain.

ELASTOGRAPHIC ANALYSIS OF THE SUPRASPINATUS TENDON IN DIFFERENT AGE GROUPS.

OBJECTIVE: To compare the mechanical properties of the supraspinatus tendon in different age groups using Supersonic Shearwave Imaging (SSI) elastography. METHODS: We evaluated 38 healthy individuals of both genders, 20 being in the range of 20 to 35 years and 18 being over 60 years. The shear modulus of the supraspinatus tendon was measured by SSI elastography, always on the right side. Means between age groups were compared and statistically analyzed using the Shapiro-Wilk normality test followed by the student's t-test and were established as a statistically significant value of p ≤ 0.05. RESULTS: A statistically significant difference was observed when the mean values of the shear modulus of the supraspinatus tendon of young adults (23.98 ± 9.94 KpA) were compared with those of older adults (17.92 ± 6.17 KpA). CONCLUSION: We found a difference between the means of the shear modulus measured by the SSI elastography, showing a significant decrease of the shear modulus with the chronological age progression. Level of Evidence III, Diagnostic Studies - Investigating a Diagnostic Test.

OBJETIVO: Comparar as propriedades mecânicas do tendão supraespinal em diferentes grupos etários, utilizando a elastografia Supersonic Shearwave Imaging (SSI). MÉTODOS: Foram avaliados 38 indivíduos saudáveis de ambos os sexos, sendo 20 na faixa de 20 a 35 anos e 18 acima dos 60 anos de idade. Foi aferido o módulo de cisalhamento do tendão supraespinal por elastografia SSI, sempre do lado direito. As médias entre os grupos etários foram comparadas e analisadas estatisticamente, sendo utilizado o teste de normalidade Shapiro-Wilk seguido do student t-test e estabelecido como valor de significância estatística um p ≤ 0,05. RESULTADOS: Foi evidenciada diferença estatisticamente significativa quando comparadas as médias do módulo de cisalhamento do tendão supraespinal dos adultos jovens (23,98 ± 9,94 KpA) com a dos idosos (17,92 ± 6,17 KpA). CONCLUSÃO: Houve diferença entre as médias do módulo de cisalhamento medido pela elastografia com SSI, demonstrando diminuição significativa do módulo de cisalhamento com a progressão da idade cronológica. Nível de Evidência III, Estudos diagnósticos - Investigação de um exame para diagnóstico.