High-frequency ultrasound measurement using fiber grating laser hydrophone

2008 ◽  
Author(s):  
Li-Yang Shao ◽  
Sien-Ting Lau ◽  
Xinyong Dong ◽  
Yong-Jun Wang ◽  
Shun-Yee Liu ◽  
...  
Keyword(s):  
High Frequency ◽  
Ultrasound Measurement ◽  
Fiber Grating ◽  
High Frequency Ultrasound ◽  
Frequency Ultrasound

scholarly journals Influence of Microstructure on the High-Frequency Ultrasound Measurement of Peak Density

2018 ◽  
Vol 1 (4) ◽  
Author(s):  
Jeremy Stromer ◽  
Leila Ladani
Keyword(s):  
Cross Section ◽  
High Frequency ◽  
Scattering Cross Section ◽  
Ultrasound Measurement ◽  
Sphere Diameter ◽  
High Frequency Ultrasound ◽  
Total Scattering ◽  
Peak Density ◽  
Scattering Cross ◽  
Frequency Ultrasound

Peak density is an ultrasound measurement, which has been found to vary according to microstructure, and is defined as the number of local extrema within the resulting power spectrum of an ultrasound measurement. However, the physical factors which influence peak density are not fully understood. This work studies the microstructural characteristics which affect peak density through experimental, computationa,l and analytical means for high-frequency ultrasound of 22–41 MHz. Experiments are conducted using gelatin-based phantoms with glass microsphere scatterers with diameters of 5, 9, 34, and 69 μm and number densities of 1, 25, 50, 75, and 100 mm−3. The experiments show the peak density to vary according to the configuration. For example, for phantoms with a number density of 50 mm−3, the peak density has values of 3, 5, 9, and 12 for each sphere diameter. Finite element simulations are developed and analytical methods are discussed to investigate the underlying physics. Simulated results showed similar trends in the response to microstructure as the experiment. When comparing scattering cross section, peak density was found to vary similarly, implying a correlation between the total scattering and the peak density. Peak density and total scattering increased predominately with increased particle size but increased with scatterer number as well. Simulations comparing glass and polystyrene scatterers showed dependence on the material properties. Twenty-four of the 56 test cases showed peak density to be statistically different between the materials. These values behaved analogously to the scattering cross section.

Extraction of Mechanical Properties of Articular Cartilage From Osmotic Swelling Behavior Monitored Using High Frequency Ultrasound

2006 ◽  
Vol 129 (3) ◽  
pp. 413-422 ◽  
Author(s):  
Q. Wang ◽  
Y. P. Zheng ◽  
H. J. Niu ◽  
A. F. T. Mak
Keyword(s):  
Mechanical Properties ◽  
Articular Cartilage ◽  
High Frequency ◽  
Weight Bearing ◽  
Ultrasound Measurement ◽  
High Frequency Ultrasound ◽  
Water Fraction ◽  
Layer Interface ◽  
Osmotic Loading ◽  
Frequency Ultrasound

Articular cartilage is a biological weight-bearing tissue covering the bony ends of articulating joints. Negatively charged proteoglycan (PG) in articular cartilage is one of the main factors that govern its compressive mechanical behavior and swelling phenomenon. PG is nonuniformly distributed throughout the depth direction, and its amount or distribution may change in the degenerated articular cartilage such as osteoarthritis. In this paper, we used a 50MHz ultrasound system to study the depth-dependent strain of articular cartilage under the osmotic loading induced by the decrease of the bathing saline concentration. The swelling-induced strains under the osmotic loading were used to determine the layered material properties of articular cartilage based on a triphasic model of the free-swelling. Fourteen cylindrical cartilage-bone samples prepared from fresh normal bovine patellae were tested in situ in this study. A layered triphasic model was proposed to describe the depth distribution of the swelling strain for the cartilage and to determine its aggregate modulus Ha at two different layers, within which Ha was assumed to be linearly dependent on the depth. The results showed that Ha was 3.0±3.2, 7.0±7.4, 24.5±11.1MPa at the cartilage surface, layer interface, and deep region, respectively. They are significantly different (p<0.01). The layer interface located at 70%±20% of the overall thickness from the uncalcified-calcified cartilage interface. Parametric analysis demonstrated that the depth-dependent distribution of the water fraction had a significant effect on the modeling results but not the fixed charge density. This study showed that high-frequency ultrasound measurement together with triphasic modeling is practical for quantifying the layered mechanical properties of articular cartilage nondestructively and has the potential for providing useful information for the detection of the early signs of osteoarthritis.

High frequency ultrasound measurement of digital dermal thickness in systemic sclerosis

2009 ◽  
Vol 69 (6) ◽  
pp. 1140-1143 ◽  
Author(s):  
Olga Kaloudi ◽  
Francesca Bandinelli ◽  
Emilio Filippucci ◽  
Maria Letizia Conforti ◽  
Irene Miniati ◽  
...  
Keyword(s):  
Systemic Sclerosis ◽  
High Frequency ◽  
Interobserver Variability ◽  
Ultrasound Measurement ◽  
Skin Thickness ◽  
Intraobserver Variability ◽  
High Frequency Ultrasound ◽  
Dermal Thickness ◽  
Dermal Thickening ◽  
Frequency Ultrasound

BackgroundCurrently, assessment of dermal thickness in systemic sclerosis (SSc) is performed by palpation and assessment using the modified Rodnan skin score (mRSS).ObjectiveTo verify whether high frequency ultrasound (US) may be a reliable and a reproducible method to measure digital dermal thickness.MethodsIn 70 patients with SSc, skin thickness was evaluated with US by 2 observers at 2 different sites on the second digit of the dominant limb to determine the interobserver variability. Patients and controls were examined twice by the first observer for intraobserver variability. Patients were divided into three subgroups according to the phase of the disease (oedematous, fibrotic or atrophic).ResultsAt both examined areas, US showed a significant dermal thickening (p<0.001) in the whole group of patients with SSc. A low intraobserver and interobserver variability was found. A highly significant correlation between the global mRSS and the local dermal thickness at the two examined sites (p=0.032, p=0.021) was detected. Skin thickness was significantly higher in the oedematous than in the fibrotic group (p<0.001) and significantly higher in the fibrotic and the oedematous group (p<0.001) than in the atrophic group (p<0.002).ConclusionsUS is a reliable tool giving reproducible results, and is able to detect digital dermal thickening in SSc.

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