In cancellous bone, longitudinal waves often separate into fast and slow depending on the alignment of bone trabeculae. This interesting phenomenon becomes an effective tool for diagnosis osteoporosis because wave propagation behavior depends structure. We have, therefore, simulated in such a complex medium by finite-difference time-domain (FDTD) method, using three-dimensional X-ray computer tomography (CT) model actual bone. this simulation, experimentally observed acoustic constants...

Previous studies have shown that interference between fast waves and slow can lead to observed negative dispersion in cancellous bone. In this study, the effects of overlapping on measurements apparent attenuation as a function propagation distance are investigated along with methods analysis used determine properties. Two applied simulated data were generated based experimentally acquired signals taken from bovine specimen. The first method uses time-domain approach was dictated by...

Ultrasound propagation in cancellous bone (porous media) under the condition of closed pore boundaries was investigated. A and two plate-like cortical bones obtained from a racehorse were prepared. water-immersion ultrasound technique MHz range three-dimensional elastic finite-difference time-domain (FDTD) method used to investigate waves. The experiments simulations showed clear separation incident longitudinal wave into fast slow findings advance evaluation based on two-wave phenomenon for...

Comparative study of longitudinal wave propagation in cancellous bone was performed. We simulated with the finite-difference time-domain (FDTD) method using a three-dimensional X-ray computer tomography (CT) model an actual bone. also experimentally measured waves that propagated identical specimen under similar conditions. The speeds fast and amplitudes slow at small ROIs (region interest) were examined. found good correlations speed between data. peak amplitude ratio two experimental...

Fast and slow longitudinal waves can propagate through cancellous bone in the direction of strong trabecular orientation. In vivo experiments, cortical layer surrounding is considered to affect fast wave propagations. this study, effects were investigated using stratified models bone. experimental simulated results, it was shown that boundary condition between regions affected both waves, particularly wave. The could be clearly observed for model with a distinct boundary, but amplitude...

An ultrasonic pulse propagating in cancellous bone can be separated into two waves depending on the condition of specimen. These waves, which are called fast wave and slow wave, provide important information for diagnosis osteoporosis. The present study proposes to utilize a signal processing method that extracts instantaneous frequency (IF) waveforms from multiple spectral channels. was expected able show detailed time-frequency properties being transmitted through bone. employed method,...

The two-wave phenomenon in a cancellous bone surrounded by cortical was investigated using the specimens obtained from large mammals. Measurements were performed laboratory-built poly(vinylidene fluoride) (PVDF) transducers excited one-cycle sinusoidal wave at 1 MHz. In addition to experimental ultrasonic measurements, finite-difference time-domain (FDTD) simulation X-ray micro computed tomography (micro-CT) images (resolution: 48 µm) of specimens. clear separation fast and slow waves not...

Fast and slow waves were detected in a bovine cancellous bone sample for thicknesses ranging from 7 to 12 mm using bandlimited deconvolution the modified least-squares Prony's method with curve fitting (MLSP + CF). Bandlimited consistently isolated two linear-with-frequency attenuation coefficients as evidenced by high correlation between coefficient frequency: 0.997 ± 0.002 (fast wave) 0.986 0.013 (slow (mean standard deviation). Average root-mean-squared (RMS) differences algorithms phase...

The received signal in through-transmission ultrasound measurements of cancellous bone consists two longitudinal waves, called the fast and slow waves. Analysis these waves may reveal characteristics that would be good indicators osteoporosis. Because often overlap, decomposition is an important problem characterization quality. This study proposes a accurate method based on frequency domain interferometry imaging with modified wave transfer function uses phase rotation parameter. proposed...

Ultrasound propagation in a heterogeneous cortical bone was studied. Using bovine radius, the longitudinal wave velocity distribution axial direction experimentally measured MHz range. The bilinear interpolation and piecewise cubic Hermite methods were applied to create three-dimensional (3D) precise model of using experimental data. By assuming uniaxial anisotropy bone, distributions all elastic moduli 3D estimated. finite-difference time-domain method used simulate ultrasonic propagation....

Ultrasonic waves targeted on cancellous bone separates into fast and slow according to the alignment of trabeculae. The characteristics specimen, however, can sometimes result in ambiguous wave separation. In this study, we proposed using wavelet transform as a new method analyzing ultrasonic waveforms. Using continuous transform, two components were separated by fitting two-dimensional Gaussian function scalogram. relationship between volume fraction peak amplitude lower- higher-frequency...

Conclusion: This study showed that it is possible to transmit language information using bone-conducted ultrasound (BCU) in normal-hearing subjects. Our results suggest the possibility of a difference speech recognition between BCU and air-conducted audible sound (ACAS). Objective: Ultrasound was when delivered by bone conduction. Some profoundly deaf subjects as well can discriminate whose amplitude modulated different sounds. These findings usefulness developing ultrasonic hearing aid...

An ultrasonic system is good for the evaluation of children because its noninvasiveness. The bone measurement LD-100 has been developed on basis principle fast and slow wave phenomenon in wrist bone. In small bones such as those children, there are some problems due to influences circumferential waves waves. When diameters focused transducers were small, appearance around cortical became late, it could avoid one

Echolocating bats exhibit sophisticated sonar behaviors using ultrasounds with actively adjusted acoustic characteristics (e.g., frequency and time-frequency structure) depending on the situation. In this study, utility of ultrasound in human echolocation was examined. By listening to ultrasonic echoes a shifted pitch be audible, participants (i.e., sighted novices) could discriminate three-dimensional (3D) roundness edge contours. This finding suggests that sounds suitable wavelengths...

Fast and slow longitudinal waves can propagate through cancellous bone in the direction of strong trabecular orientation. In vivo experiments, cortical layer surrounding is considered to affect fast wave propagations. this study, effects were investigated using stratified models bone. experimental simulated results, it was shown that boundary condition between regions affected both waves, particularly wave. The could be clearly observed for model with a distinct boundary, but amplitude...

Two longitudinal wave modes (called fast and slow modes) have been shown to propagate in cancellous bone. In this study, the effect of viscoelasticity on two-wave phenomenon was investigated using a 3-D finite-difference time-domain (FDTD) method accounting for viscoelastic phenomena. The results show that amplitude increases when bone increase, while opposite behavior obtained wave.

Abstract Audible sound with a low‐frequency vibration brings about hydrodynamic alignment of supramolecular nanofiber in solution. Design the nanoscale molecules and molecular assemblies, which can sense wide range frequencies audible wave high sensitivity, develops sound‐driven machines sound‐responsive nanomaterials, is also interesting for investigation unknown physical interactions between vibrations. In this study, it was found that nanofiber, composed an anthracene derivative AN , n...

A prototype for a bone-conducted ultrasonic hearing aid was developed the profoundly deaf. Previous studies using revealed intelligibility only with use of acoustic media in transmitting language information. In this study, we investigated effects visual information (lip-reading information) on ultrasound perception normal-hearing individuals. We found that lip-reading had clear perception, showing simultaneous presentation audio and improved to levels sufficient speech perception. Our...

Ultrasound signals that pass through cancellous bone may be considered to consist of two longitudinal waves, which are called fast and slow waves. Accurate decomposition these waves is highly beneficial in determination the characteristics bone. In present study, a method using wave transfer function with phase rotation parameter was applied received have passed bovine specimens various volume total (BV/TV) ratios simulation where elastic finite-difference time-domain used ultrasound...

The effect of the heterogeneity long cortical bone is an important factor when applying axial transmission technique. In this study, longitudinal wave velocity distributions in specimens from mid-shaft a bovine femur were measured, MHz range. Bilinear interpolation and piecewise cubic Hermite interpolating polynomial method used to construct three-dimensional (3D) models with resolution 40 μm. By assuming uniaxial anisotropy using results previous experimental studies [Yamato, Matsukawa,...