501 Changes of muscle fiber length in vivo during walking as revealed by ultrasound images

2008 ◽  
Vol 2007.20 (0) ◽  
pp. 165-166
Author(s):  
Naoto SASAGAWA ◽  
Tasuku MIYOSHI ◽  
Hiroyuki KOYAMA ◽  
Takashi KOMEDA ◽  
Shin-Ichiro YAMAMOTO
Keyword(s):  
Muscle Fiber ◽  
Fiber Length ◽  
Ultrasound Images

Transverse Strain of Aponeurosis in Human Tibialis Anterior Muscle at Rest and during Contraction at Different Joint Angles

2003 ◽  
Vol 19 (1) ◽  
pp. 39-48 ◽  
Author(s):  
Tetsuro Muraoka ◽  
Tadashi Muramatsu ◽  
Hiroaki Kanehisa ◽  
Tetsuo Fukunaga
Keyword(s):  
Muscle Fiber ◽  
Resting State ◽  
Tibialis Anterior ◽  
Fiber Length ◽  
Tibialis Anterior Muscle ◽  
Transverse Strain ◽  
Relative Width ◽  
Significant Difference ◽  
Human Tibialis Anterior Muscle

The aim of the present study was to determine the transverse strain of aponeuroses in human tibialis anterior muscle (TA) in vivo and to clarify the influence of muscle fiber length and state of contraction on the transverse strain. Sagittal and horizontal images of TA were taken in seven men and one woman at ankle angles of –20° (dorsiflexed direction), 0° (neutral anatomic position), and 45° (plantar-flexed direction) both at rest and during submaximal dorsiflexion contraction (20 Nm: 0° and 45°; 10 Nm: –20°) using B-mode ultrasonography. The width of the TA central aponeurosis changed from 21.7 ± 1.0 (mean ±SE) to 25.5 ± 1.1 mm when muscle fiber length changed from 91.0 ± 3.5 (45° in the resting state) to 55.1 ± 3.2 mm (–20° in the active state). The transverse strain of the TA central aponeurosis, which was change in relative width compared with the width at 45° in the resting state, increased when the muscle fiber length decreased. The transverse strain of the TA central aponeurosis was directly proportional to the muscle fiber length to the –1/2 power in both resting and active states (R= 0.81 and 0.74,p< 0.05 for both), and there was no significant difference (p< 0.05) between correlation coefficients and regression slopes for resting and active states. The findings suggest that the transverse strain of the TA central aponeurosis was closely related to muscle fiber length and that the transverse strain of the aponeurosis should be considered for accurate 3-D muscle modeling.

scholarly journals In vivo muscle force-length behavior during steady-speed hopping in tammar wallabies.

1998 ◽  
Vol 201 (11) ◽  
pp. 1681-1694 ◽  
Author(s):  
A A Biewener ◽  
D D Konieczynski ◽  
R V Baudinette
Keyword(s):  
Energy Expenditure ◽  
Muscle Fiber ◽  
Fiber Length ◽  
Strain Energy ◽  
Length Change ◽  
Metabolic Energy ◽  
Lateral Gastrocnemius ◽  
Length Changes ◽  
Tendon Force

Moderate to large macropodids can increase their speed while hopping with little or no increase in energy expenditure. This has been interpreted by some workers as resulting from elastic energy savings in their hindlimb tendons. For this to occur, the muscle fibers must transmit force to their tendons with little or no length change. To test whether this is the case, we made in vivo measurements of muscle fiber length change and tendon force in the lateral gastrocnemius (LG) and plantaris (PL) muscles of tammar wallabies Macropus eugenii as they hopped at different speeds on a treadmill. Muscle fiber length changes were less than +/-0.5 mm in the plantaris and +/-2.2 mm in the lateral gastrocnemius, representing less than 2 % of total fiber length in the plantaris and less than 6 % in the lateral gastrocnemius, with respect to resting length. The length changes of the plantaris fibers suggest that this occurred by means of elastic extension of attached cross-bridges. Much of the length change in the lateral gastrocnemius fibers occurred at low force early in the stance phase, with generally isometric behavior at higher forces. Fiber length changes did not vary significantly with increased hopping speed in either muscle (P&gt;0.05), despite a 1. 6-fold increase in muscle-tendon force between speeds of 2.5 and 6.0 m s-1. Length changes of the PL fibers were only 7+/-4 % and of the LG fibers 34+/-12 % (mean +/- S.D., N=170) of the stretch calculated for their tendons, resulting in little net work by either muscle (plantaris 0.01+/-0.03 J; gastrocnemius -0.04+/-0.30 J; mean +/- s.d. ). In contrast, elastic strain energy stored in the tendons increased with increasing speed and averaged 20-fold greater than the shortening work performed by the two muscles. These results show that an increasing amount of strain energy stored within the hindlimb tendons is usefully recovered at faster steady hopping speeds, without being dissipated by increased stretch of the muscles' fibers. This finding supports the view that tendon elastic saving of energy is an important mechanism by which this species is able to hop at faster speeds with little or no increase in metabolic energy expenditure.

scholarly journals Development of a semi-automated segmentation tool for high frequency ultrasound image analysis of mouse echocardiograms

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Kristi Powers ◽  
Raymond Chang ◽  
Justin Torello ◽  
Rhonda Silva ◽  
Yannick Cadoret ◽  
...  
Keyword(s):  
Image Analysis ◽  
Automated Analysis ◽  
Structure And Function ◽  
Ultrasound Images ◽  
Cardiac Structure ◽  
Short Axis ◽  
Pixel Intensity ◽  
Cardiac Structure And Function ◽  
And Function

AbstractEchocardiography is a widely used and clinically translatable imaging modality for the evaluation of cardiac structure and function in preclinical drug discovery and development. Echocardiograms are among the first in vivo diagnostic tools utilized to evaluate the heart due to its relatively low cost, high throughput acquisition, and non-invasive nature; however lengthy manual image analysis, intra- and inter-operator variability, and subjective image analysis presents a challenge for reproducible data generation in preclinical research. To combat the image-processing bottleneck and address both variability and reproducibly challenges, we developed a semi-automated analysis algorithm workflow to analyze long- and short-axis murine left ventricle (LV) ultrasound images. The long-axis B-mode algorithm executes a script protocol that is trained using a reference library of 322 manually segmented LV ultrasound images. The short-axis script was engineered to analyze M-mode ultrasound images in a semi-automated fashion using a pixel intensity evaluation approach, allowing analysts to place two seed-points to triangulate the local maxima of LV wall boundary annotations. Blinded operator evaluation of the semi-automated analysis tool was performed and compared to the current manual segmentation methodology for testing inter- and intra-operator reproducibility at baseline and after a pharmacologic challenge. Comparisons between manual and semi-automatic derivation of LV ejection fraction resulted in a relative difference of 1% for long-axis (B-mode) images and 2.7% for short-axis (M-mode) images. Our semi-automatic workflow approach reduces image analysis time and subjective bias, as well as decreases inter- and intra-operator variability, thereby enhancing throughput and improving data quality for pre-clinical in vivo studies that incorporate cardiac structure and function endpoints.

Adaptation of Cardinal Points Symmetry Landmarks Distribution Model to in-vivo B-Mode Ultrasound Images of Transverse Cross-section of Carotid Arteries

2021 ◽  
Vol 6 (7) ◽  
pp. 107-113
Author(s):  
Charles Nnamdi Udekwe ◽  
Akinlolu Adediran Ponnle
Keyword(s):  
Carotid Artery ◽  
Cross Section ◽  
Carotid Arteries ◽  
Region Of Interest ◽  
Transverse Cross Section ◽  
Transverse Plane ◽  
Distribution Model ◽  
Ultrasound Images ◽  
Symmetry Line

The geometry of the imaged transverse cross-section of carotid arteries in in-vivo B-mode ultrasound images are most times irregular, unsymmetrical, full of speckles and usually non-uniform. We had earlier developed a technique of cardinal point symmetry landmark distribution model (CPS-LDM) to completely characterize the Region of Interest (ROI) of the geometric shape of thick-walled simulated B-mode ultrasound images of carotid artery imaged in the transverse plane, but this was based on the symmetric property of the image. In this paper, this developed technique was applied to completely characterize the region of interest of the geometric shape of in-vivo B-mode ultrasound images of non-uniform carotid artery imaged in the transverse plane. In order to adapt the CPS-LD Model to the in-vivo carotid artery images, the single VS-VS vertical symmetry line common to the four ROIs of the symmetric image is replaced with each ROI having its own VS-VS vertical symmetry line. This adjustment enables the in-vivo carotid artery images possess symmetric properties, hence, ensuring that all mathematical operations of the CPS-LD Model are conveniently applied to them. This adaptability was observed to work well in segmenting the in-vivo carotid artery images. This paper shows the adaptive ability of the developed CPS-LD Model to successfully annotate and segment in-vivo B-mode ultrasound images of carotid arteries in the transverse cross-sectional plane either they are symmetrical or unsymmetrical.

scholarly journals Enhancing ultrasound texture differences for developing an in vivo 'virtual histology' approach to bovine ovarian imaging

2007 ◽  
Vol 19 (8) ◽  
pp. 910 ◽  
Author(s):  
Mark G. Eramian ◽  
Gregg P. Adams ◽  
Roger A. Pierson
Keyword(s):  
Image Processing ◽  
Ultrasound Image ◽  
Ultrasound Images ◽  
Virtual Histology ◽  
Form And Function ◽  
Non Invasive ◽  
Candidate Image ◽  
And Function ◽  
Processing Techniques

A ‘virtual histology’ can be thought of as the ‘staining’ of a digital ultrasound image via image processing techniques in order to enhance the visualisation of differences in the echotexture of different types of tissues. Several candidate image-processing algorithms for virtual histology using ultrasound images of the bovine ovary were studied. The candidate algorithms were evaluated qualitatively for the ability to enhance the visual differences in intra-ovarian structures and quantitatively, using standard texture description features, for the ability to increase statistical differences in the echotexture of different ovarian tissues. Certain algorithms were found to create textures that were representative of ovarian micro-anatomical structures that one would observe in actual histology. Quantitative analysis using standard texture description features showed that our algorithms increased the statistical differences in the echotexture of stroma regions and corpus luteum regions. This work represents a first step toward both a general algorithm for the virtual histology of ultrasound images and understanding dynamic changes in form and function of the ovary at the microscopic level in a safe, repeatable and non-invasive way.

Deconvolution of in-Vivo Ultrasound B-Mode Images

1993 ◽  
Vol 15 (2) ◽  
pp. 122-133 ◽  
Author(s):  
Jørgen Arendt Jensen ◽  
Jan Mathorne ◽  
Torben Gravesen ◽  
Bjarne Stage
Keyword(s):  
Portal Vein ◽  
Ultrasound Images ◽  
Medical Ultrasound ◽  
Axial Resolution ◽  
One Dimensional ◽  
Rf Signal ◽  
Ultrasound Pulse

An algorithm for deconvolution of medical ultrasound images is presented. The procedure involves estimation of the basic one-dimensional ultrasound pulse, determining the ratio of the covariance of the noise to the covariance of the reflection signal, and finally deconvolution of the rf signal from the transducer. Using pulse and covariance estimators makes the approach self-calibrating, as all parameters for the procedure are estimated from the patient under investigation. An example of use on a clinical, in-vivo image is given. A 2 × 2 cm region of the portal vein in a liver is deconvolved. An increase in axial resolution by a factor of 2.4 is obtained. The procedure can also be applied to whole images, when it is ensured that the rf signal is properly measured. A method for doing that is outlined.

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