588 research outputs found

    Quantitative Ultrasound and B-mode Image Texture Features Correlate with Collagen and Myelin Content in Human Ulnar Nerve Fascicles

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    We investigate the usefulness of quantitative ultrasound (QUS) and B-mode texture features for characterization of ulnar nerve fascicles. Ultrasound data were acquired from cadaveric specimens using a nominal 30 MHz probe. Next, the nerves were extracted to prepare histology sections. 85 fascicles were matched between the B-mode images and the histology sections. For each fascicle image, we selected an intra-fascicular region of interest. We used histology sections to determine features related to the concentration of collagen and myelin, and ultrasound data to calculate backscatter coefficient (-24.89 dB ±\pm 8.31), attenuation coefficient (0.92 db/cm-MHz ±\pm 0.04), Nakagami parameter (1.01 ±\pm 0.18) and entropy (6.92 ±\pm 0.83), as well as B-mode texture features obtained via the gray level co-occurrence matrix algorithm. Significant Spearman's rank correlations between the combined collagen and myelin concentrations were obtained for the backscatter coefficient (R=-0.68), entropy (R=-0.51), and for several texture features. Our study demonstrates that QUS may potentially provide information on structural components of nerve fascicles

    Diffusion-tensor MRI methods to study and evaluate muscle architecture

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    The thesis describes the development of various approaches for measuring muscle architectural parameters using Diffusion Tensor MR Imaging (DTI). It also illustrates how to apply them to study changes in muscle architecture after an injury prevention program.In Chapter 2, because manual segmentation of muscles is cumbersome, we validated a semi-automatic framework for estimating DTI indices in upper leg muscles. This method reduced segmentation time by a factor of three in a cross-sectional study design and can be used fully automatically in a longitudinal assessment of changes in DTI indices.Chapter 3 was a feasibility study measuring fiber orientation changes with DTI in calf muscles and sub-compartments of the Soleus and Tibialis Anterior during plantarflexion and dorsiflexion. Differences in fiber orientations corresponded to the known agonist-antagonist function of the muscles. This shows that DTI can be utilized to assess changes in muscle orientation due to posture or training.In Chapter 4, we compared DTI fiber tractography for Vastus Lateralis fiber architecture assessment with 3D ultrasonography (3D-US). We discovered that both methods have their advantages and disadvantages, with the agreement between the two techniques being moderate.Finally, in Chapter 5, we examined the effects of a hamstring injury prevention exercise on the muscle architectural parameters of basketball players. DTI was employed to quantify changes in fiber orientation and length using tractography and fiber orientation maps. It was observed that the Semitendinosus fascicle length increased after the Nordics exercise, while the Biceps Femoris long head fiber orientation decreased following the Divers intervention

    Estimation of Muscle Fiber Orientation in Ultrasound Images Using Revoting Hough Transform (RVHT)

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    2008-2009 > Academic research: refereed > Publication in refereed journalAccepted ManuscriptPublishe

    Automatic thickness estimation for skeletal muscle in ultrasonography: evaluation of two enhancement methods

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    BACKGROUND: Ultrasonography is a convenient technique to investigate muscle properties and has been widely used to look into muscle functions since it is non-invasive and real-time. Muscle thickness, a quantification which can effectively reflect the muscle activities during muscle contraction, is an important measure for musculoskeletal studies using ultrasonography. The traditional manual operation to read muscle thickness is subjective and time-consuming, therefore a number of studies have focused on the automatic estimation of muscle fascicle orientation and muscle thickness, to which the speckle noises in ultrasound images could be the major obstacle. There have been two popular methods proposed to enhance the hyperechoic regions over the speckles in ultrasonography, namely Gabor Filtering and Multiscale Vessel Enhancement Filtering (MVEF). METHODS: A study on gastrocnemius muscle is conducted to quantitatively evaluate whether and how these two methods could help the automatic estimation of the muscle thickness based on Revoting Hough Transform (RVHT). The muscle thickness results obtained from each of the two methods are compared with the results from manual measurement, respectively. Data from an aged subject with cerebral infarction is also studied. RESULTS: It’s shown in the experiments that, Gabor Filtering and MVEF can both enable RVHT to generate comparable results of muscle thickness to those by manual drawing (mean ± SD, 1.45 ± 0.48 and 1.38 ± 0.56 mm respectively). However, the MVEF method requires much less computation than Gabor Filtering. CONCLUSIONS: Both methods, as preprocessing procedure can enable RVHT the automatic estimation of muscle thickness and MVEF is believed to be a better choice for real-time applications

    Comparison of sonographic techniques for the assessment of biceps femoris long head architecture

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    Objetivo: Avaliar a repetibilidade e a concordância entre três técnicas sonográficas usadas para quantificar a arquitetura da cabeça longa do bicípite femoral (BFlh): i) imagem estática; ii) extended field-of-view (EFOV) com o caminho da sonda de ultrassom de forma linear (EFOV linear); e iii) EFOV com o percurso da sonda de forma não linear (EFOV não linear) para seguir as complexas trajetórias dos fascículos. Método: Vinte sujeitos (24,4 ± 5,7 anos; 175 ± 0,8 cm; 73 ± 9,0 kg) sem historial de lesão nos isquiotibiais foram convidados a participar neste estudo. Foi utilizado um aparelho de ultrassom ligado a uma sonda linear de 6 cm, operando a uma frequência de 10 MHz para avaliar a arquitetura da BFlh em B mode. Resultados: A sonda de ultrassom foi posicionada a 52,0 ± 5,0% do comprimento do fêmur e 57,0 ± 6,0% do comprimento da BFlh. Encontramos uma repetibilidade aceitável ao avaliar o comprimento do fascículo da BFlh (ICC3,k = 0,86-0,95; SEM = 1,9-3,2 mm) e ângulo de penação (ICC3,k = 0,85-0,97; SEM = 0,8-1,1º) em todas as três técnicas sonográficas. No entanto, a técnica EFOV não linear mostrou maior repetibilidade (comprimento do fascículo ICC3,k = 0,95; ângulo de penação, ICC3,k = 0,97). A técnica de imagem estática superestimou o comprimento do fascículo (8-11%) e subestimou o ângulo de penação (8-9%) em comparação com as técnicas de EFOV. Além disso, a ordem de classificação dos sujeitos variou em cerca de 15% entre a imagem estática e o EFOV não linear.Conclusões: Embora todas as técnicas tenham apresentado boa repetibilidade, os erros absolutos foram observados com imagens estáticas (7,9 ± 6,1 mm para o comprimento do fascículo) e EFOV linear (3,7 ± 3,0 mm), provavelmente porque as complexas trajetórias dos fascículos não foram acompanhadas. A ordem de classificação dos indivíduos para o comprimento e ângulo de penação também foi diferente entre a imagem estática e o EFOV não linear. Desta forma, diferentes estimativas quanto ao risco de lesão e função muscular poderiam ter sido feitas ao usar essa técnica.Purpose: To assess the repeatability of, and measurement agreement between, three sonographic techniques used to quantify biceps femoris long head (BFlh) architecture: i) static-image; ii) extended field-of-view (EFOV) with linear ultrasound probe path (linear-EFOV); and iii) EFOV with nonlinear probe path (nonlinear-EFOV) to follow the complex fascicle trajectories. Methods: Twenty individuals (24.4±5.7 years; 175±0.8 cm; 73±9.0 kg) without history of hamstring strain injury were invited to participate in this study. An ultrasound scanner coupled with 6-cm linear probe operating at a 10-MHz frequency was used to assess BFlh architecture in B-mode. Results: The ultrasound probe was positioned at 52.0±5.0% of femur length and 57.0±6.0% of BFlh length. We found an acceptable repeatability when assessing BFlh fascicle length (ICC3,k = 0.86-0.95; SEM = 1.9-3.2 mm) and angle (ICC3,k = 0.85-0.97; SEM = 0.8-1.1o) using all three sonographic techniques. However, the nonlinear-EFOV technique showed the highest repeatability (fascicle length ICC3,k = 0.95; fascicle angle, ICC3,k = 0.97). The static-image technique overestimated fascicle length (8-11%) and underestimated fascicle angle (8-9%) compared to both EFOV techniques. Also, the rank order of individuals varied by ~15% between static-image and nonlinear-EFOV techniques when assessing the fascicle length. Conclusions: Although all techniques showed good repeatability, absolute errors were observed using static-image (7.9±6.1 mm for fascicle length) and linear-EFOV (3.7±3.0 mm), probably because the complex fascicle trajectories were not followed. The rank order of individuals for fascicle length and angle were also different between static-image and nonlinear-EFOV, so different muscle function and injury risk estimates could likely be made when using this technique
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