Pulse-echo speed-of-sound imaging using convex probes.

Computed ultrasound tomography in echo mode (CUTE) is a new ultrasound (US)-based medical imaging modality with promise for diagnosing various types of disease based on the tissue's speed of sound (SoS). It is developed for conventional pulse-echo US using handheld probes and can thus be implemented in state-of-the-art medical US systems. One promising application is the quantification of the liver fat fraction in fatty liver disease. So far, CUTE was using linear array probes where the imaging depth is comparable to the aperture size. For liver imaging, however, convex probes are preferred since they provide a larger penetration depth and a wider view angle allowing to capture a large area of the liver. With the goal of liver imaging in mind, we adapt CUTE to convex probes, with a special focus on discussing strategies that make use of the convex geometry in order to make our implementation computationally efficient. We then demonstrate in an abdominal imaging phantom that accurate quantitative SoS using convex probes is feasible, in spite of the smaller aperture size in relation to the image area compared to linear arrays. A preliminary in vivo result of liver imaging confirms this outcome, but also indicates that deep quantitative imaging in the real liver can be more challenging, probably due to the increased complexity of the tissue compared to phantoms

In plane quantification of in vivo muscle elastic anisotropy factor by steered ultrasound pushing beams

Skeletal muscles are organized into distinct layers and exhibit anisotropic characteristics across various scales. Assessing the arrangement of skeletal muscles may provide valuable biomarkers for diagnosing muscle related pathologies and evaluating the efficacy of clinical interventions. In this study, we propose a novel ultrafast ultrasound sequence constituted of steered pushing beams was proposed for ultrasound elastography applications in transverse isotropic muscle. Based on the propagation of the shear wave vertical mode, it is possible to fit the experimental results to retrieve in the same imaging plane, the shear modulus parallel to fibers as well as the elastic anisotropy factor. The technique was demonstrated in vitro in phantoms and ex vivo in fusiform beef muscles. At last, the technique was applied in vivo on fusiform muscles (biceps braachi) and mono-penate muscles (gastrocnemius medialis) during stretching and contraction. This novel sequence provides access to new structural and mechanical biomarkers of muscle tissue, including the elastic anisotropy factor, within the same imaging plane. Additionally, it enables the investigation of multiples parameters during muscle active and passive length changes

Initial examples of the SOLUS multimodal potential

We present initial evidence of the SOLUS potential for the multimodal non-invasive diagnosis of breast cancer by describing the correlation between optical and standard radiological data and analyzing a case study

Resistivity Index Mapping in Kidney Based on Ultrasensitive Pulsed-Wave Doppler and Automatic Spectrogram Envelope Detection

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Imaging device with image acquisition rate optimization

<p> The disclosure includes a method of acquiring high-resolution ultrasound images using an array of transducers using successive transmission matrices. </p

Quantification of in vivo muscle elastic anisotropy factor by steered push beams

Through the past few years, ultrasound (US) elastography has been widely applied to quantify muscle anisotropy. Generally, it is performed with an acoustic radiation force push beam that generates shear waves followed by US imaging. Recently, Ngo et al. (2021) proposed to use a steering push beam to comprehensively assess the mechanical properties of transverse isotropic skeletal muscle tissue. Here, we integrate the equation of shear vertical wave mode to the steering push beam method which allows to retrieve the mechanical parameters of anisotropic muscle tissue. Ex vivo experiments showed a good agreement between the tensile anisotropy XE found by our method and by the mechanical tensile tests. In vivo experiments were conducted to evaluate the anisotropy ratio measured by steering push beam method during different isometric contraction intensities. We observed a growing trend of this ratio with the contraction intensity in both fusiform (Biceps brachii) and pennate muscles (Medial gastrocnemius) of two healthy volunteers. Despite this trend was different between the two types of muscle architecture across contractions intensities, the overall difference had about the same magnitude for both volunteers

Quantification of in vivo muscle elastic anisotropy factor by steered push beams

International audienceThrough the past few years, ultrasound (US) elastography has been widely applied to quantify muscle anisotropy. Generally, it is performed with an acoustic radiation force push beam that generates shear waves followed by US imaging. Recently, Ngo et al. (2021) proposed to use a steering push beam to comprehensively assess the mechanical properties of transverse isotropic skeletal muscle tissue. Here, we integrate the equation of shear vertical wave mode to the steering push beam method which allows to retrieve the mechanical parameters of anisotropic muscle tissue. Ex vivo experiments showed a good agreement between the tensile anisotropy χE found by our method and by the mechanical tensile tests. In vivo experiments were conducted to evaluate the anisotropy ratio measured by steering push beam method during different isometric contraction intensities. We observed a growing trend of this ratio with the contraction intensity in both fusiform (Biceps brachii) and pennate muscles (Medial gastrocnemius) of two healthy volunteers. Despite this trend was different between the two types of muscle architecture across contractions intensities, the overall difference had about the same magnitude for both volunteers

In plane quantification of in vivo muscle elastic anisotropy factor by steered ultrasound pushing beams

International audienceAbstract Objective: Skeletal muscles are organized into distinct layers and exhibit anisotropic characteristics across various scales. Assessing the arrangement of skeletal muscles may provide valuable biomarkers for diagnosing muscle-related pathologies and evaluating the efficacy of clinical interventions. Approach: In this study, we propose a novel ultrafast ultrasound sequence constituted of steered pushing beams was proposed for ultrasound elastography applications in transverse isotropic muscle. Based on the propagation of the shear wave vertical mode, it is possible to fit the experimental results to retrieve in the same imaging plane, the shear modulus parallel to fibers as well as the elastic anisotropy factor (ratio of Young’s moduli times the shear modulus perpendicular to fibers). Main results: The technique was demonstrated in vitro in phantoms and ex vivo in fusiform beef muscles. At last, the technique was applied in vivo on fusiform muscles (biceps brachii) and mono-pennate muscles (gastrocnemius medialis) during stretching and contraction. Significance: This novel sequence provides access to new structural and mechanical biomarkers of muscle tissue, including the elastic anisotropy factor, within the same imaging plane. Additionally, it enables the investigation of multiples parameters during muscle active and passive length changes