This paper is devoted to a method of extraction guided waves phase velocities from experimental signals. Measurements are performed using an axial transmission device consisting linear arrangement emitters and receivers placed on the surface inspected specimen. The technique takes benefit both multiple validated reference wave guide. mode obtained projection in singular vectors basis. determined by values decomposition (SVD) response matrix between two arrays frequency domain. enables...

This paper reports for the first time on inverse estimation of several bone properties from guided-wave measurements in human samples. Previously, related approaches have focused ultrasonic a single property at time. The method is based two steps: multi-Lamb mode response analyzed using singular value decomposition signal processing recently introduced field, then an identification procedure run to find thickness and anisotropic elastic considered specimen. Prior bone, validated cortical...

The 2-D Fourier transform analysis of multichannel signals is a straightforward method to extract the dispersion curves guided modes. Basically, time recorded at several positions along waveguide are converted wavenumber-frequency space, so that (i.e., frequency-dependent wavenumbers) modes can be extracted by detecting peaks energy trajectories. In order improve curve extraction low-amplitude propagating in cortical bone, multiemitter and multireceiver transducer array has been developed...

Recent bone quantitative ultrasound approaches exploit the multimode waveguide response of long bones for assessing properties such as cortical thickness and stiffness. Clinical applications remain, however, challenging, impact soft tissue on guided waves characteristics is not fully understood yet. In particular, it must be clarified whether incorporated in models needed to infer reliable properties. We hypothesize that an inverse procedure using a free plate model can applied retrieve...

ABSTRACT Recent ultrasound (US) axial transmission techniques exploit the multimode waveguide response of long bones to yield estimates cortical bone structure characteristics. This pilot cross-sectional study aimed evaluate performance at one-third distal radius a bidirectional technique (BDAT) discriminate between fractured and nonfractured postmenopausal women. Cortical thickness (Ct.Th) porosity (Ct.Po) were obtained for 201 women: 109 (62.6 ± 7.8 years), 92 with one or more nontraumatic...

Cortical bone loss is not fully assessed by the current X-ray methods, and there an unmet need in identifying women at risk of osteoporotic fracture, who should receive a treatment. The last decade has seen emergence ultrasound (US) axial transmission (AT) techniques to assess cortical bone. Recent AT exploit multimode waveguide response long bones such as radius. A recent ex vivo study our group evidenced that approach can yield simultaneous estimates thickness (Ct.Th) stiffness. aim this...

Recent progress in quantitative ultrasound has exploited the multimode waveguide response of long bones. Measurements guided modes, along with suitable modeling, have potential to infer strength-related factors such as stiffness (mainly determined by cortical porosity) and thickness. However, development model-based approaches is challenging, particular because multiparametric nature inverse problem. Current estimation methods bone field rely on a number assumptions for pairing incomplete...

Blood-mimicking fluids (BMFs) play a critical role in ultrasonic imaging and Doppler flow studies by replicating the physical acoustic properties of blood. This study introduces novel soybean oil-in-water emulsion as BMF with particle size deformability akin to red blood cells. Using millifluidic device, we cross-validated profiles through both velocimetry optical tracking, demonstrating compatibility theoretical Poiseuille models. The chip, fabricated via stereolithography, provided an...

Fragility fractures are still a worldwide health burden in the context of population aging. In particular, global number hip is expected to double between 2020 and 2050. Therefore, it essential detect patients at risk fragility fracture scale. The current golden standard dual X-ray absorptiometry (DXA), providing areal bone mineral density (aBMD). Ultrasonic devices, usually more portable cheaper than represent interesting DXA alternatives as screening tools. However, operator dependency...

A rigid 24-element source-receiver array in the 10-15 kHz frequency band, connected to a programmable electronic system, was deployed Bay of Brest during spring 2005. In this 10- 18-m-deep environment, backscattered data from submerged targets were recorded. Successful detection and focusing experiments very shallow water using decomposition time reversal operator (DORT method) are shown. The ability DORT method separate echo target reverberation as well two different at 250 m is An example...

Robust signal processing methods adapted to clinical measurements of guided modes are required assess bone properties such as cortical thickness and porosity. Recently, an approach based on the singular value decomposition (SVD) multidimensional signals recorded with axial transmission array emitters receivers has been proposed for materials negligible absorption, see Minonzio et al. [J. Acoust. Soc. Am. 127, 2913–2919 (2010)]. In presence ability extract mode degrades. The objective present...

Automatic fall detection is a very active research area, which has grown explosively since the 2010s, especially focused on elderly care. Rapid of falls favors early awareness from injured person, reducing series negative consequences in health elderly. Currently, there are several systems (FDSs), mostly based predictive and machine-learning approaches. These algorithms different data sources, such as wearable devices, ambient-based sensors, or vision/camera-based While devices like inertial...

Measuring guided waves in cortical bone arouses a growing interest to assess skeletal status. In most studies, model of waveguide is proposed assist the interpretation dispersion curves. all reported investigations, mimicked as with constant thickness, which only approximates irregular geometry bone. this study, mode propagation bone-mimicking wedged plates investigated aim document influence on measured curves varying thickness and propose method overcome measurement limitations induced by...

Dispersion results in the spreading and overlapping of wave-packets, which often limits capability signal interpretation; on other hand, such a phenomenon can also be used for structure or media evaluation. In this study, authors propose an original dispersive Radon transform (DRT), is formulated as integration along set dispersion curves. Multichannel signals each individual mode concentrated to well localized region DRT domain. The proposed establishes sparse projection components provides...

The immunohistochemical (IHC) evaluation of epidermal growth factor 2 (HER2) for the diagnosis breast cancer is still qualitative with a high degree inter-observer variability, and thus requires incorporation complementary techniques such as fluorescent in situ hybridization (FISH) to resolve diagnosis. Implementing automatic algorithms classify IHC biomarkers crucial typifying tumor deciding on therapy each patient better performance. present study aims demonstrate that, using an...

Human soft tissue is an important factor that influences the assessment of human long bones using quantitative ultrasound techniques. To investigate such influence, a series tissue–bone phantoms (a bone-mimicking plate coated with layer water, glycerol or silicon rubber) were ultrasonically investigated probe multi-emitter and multi-receiver arrays in axial transmission configuration. A singular value decomposition signal processing technique was applied to extract frequency-dependent...

Some pioneering studies have shown the clinical feasibility of long bones evaluation using ultrasonic guided waves. Such a strategy is typically designed to determine dispersion information modes infer elastic and structural characteristics cortical bone. However, there are still some challenges extract multimode curves due many practical limitations, e.g., high spectral density modes, limited resolution poor signal-to-noise ratio. Recently, two representative signal processing methods been...

The estimation of cortical thickness (Ct.Th) and porosity (Ct.Po) at the tibia using axial transmission ultrasound was successfully validated ex vivo against site-matched micro-computed tomography. assessment parameters based on full-spectrum guided-wave analysis might improve prediction bone fractures in a cost-effective radiation-free manner. Cortical are key for identification patients with fragile bones. main objective this study to validate measurement Ct.Po Ct.Th non-ionizing,...

Although classical imaging is limited by the Rayleigh criterion, it has been demonstrated that subwavelength of two point-like scatterers can be achieved with probing sensors arrays, even if are located in far field sensors.However, role noise crucial to determine resolution limit.This paper proposes a quantitative study influence on obtained DORT-MUSIC method.The DORT method, French acronym for decomposition time reversal operator, consists studying invariants operator.The method combined...

Measuringguided wave propagation in long bones is of interest to the medical community. When an inclination exists between probe and tested specimen surface, a bias introduced on guided mode wavenumbers. The aim this study was generalize bidirectional axial transmission technique initially developed for first arriving signal. Validation tests were performed academic materials such bone-mimicking plate covered with either silicon or fat-mimicking layer. For any inclination, wavenumbers...

A wide range of ultrasound methods has been proposed to assess the mechanical strength bone. The axial transmission technique, which consists measuring guided elastic modes through cortical shell long bones such as radius or tibia, recently emerged one most promising approaches all bone exploration methods. Determination dispersion curves waves is therefore prime interest because they provide a large set input data required perform inverse process, and hence evaluate properties (elastic...

The goal of this work was to show that a non-absorbing free plate model can predict with reasonable accuracy guided modes measured in bone-mimicking phantoms have circular cross-section. Experiments were carried out on uncoated and coated using clinical axial transmission setup. Adjustment the experimental data yielded estimates for waveguide characteristics (thickness, bulk wave velocities). Fair agreement achieved over frequency range 0.4 1.6 MHz. A lower observed thinnest caused by...

Bone fractures are caused by diseases or accidents and a widespread problem throughout the globe. Worldwide, 1.6 millions of hip occur every year expected to rise 6.3 in 2050. The current gold standard assess fracture risk is Dual-energy X-ray Absorptiometry (DXA), which provides projected image bone from areal mineral density extracted. Ultrasound techniques have been proposed as non invasive alternatives. Recently, estimates cortical thickness porosity, obtained Bi-Directional Axial...