Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 19 of 19 for “"QUS"”.
-
Comparison of Two Bone Mineral Density Pre-Screening Tools: Qus and Ra, to the Dxa
… between BMD t-scores measured by the QUS and RA devices, compared to the DXA measurement, the gold standard. (2) Examine the agreement between osteoporosis classifications produced by the QUS and RA devices, compared to those produced by the DXA, the gold standard. Methods: 132 …
-
Quantitative ultrasonic characterization of diffuse scatterers in the presence of structures that produce coherent echoes
Quantitative ultrasound (QUS) techniques that parameterize the backscattered signal power spectrum have demonstrated significant promise for ultrasonic tissue characterization. Some QUS parameters, including the effective scatterer diameter (ESD) and the effective acoustic concentration (EAC) that …
-
Toward model-free and reference-free quantitative ultrasound
Current spectral-based quantitative ultrasound (QUS) techniques rely on a reference or a calibration signal to obtain system-independent ultrasonic scattering parameters. Adoption of QUS clinically has been hindered by (1) the need to limit clinical ultrasonic scanner settings to account for a …
-
Using quantitative ultrasound for epidemiological research : associations with risk factors for low bone mineral density in South African premenopausal women
Quantitative Ultrasound (QUS) measurement at the calcaneum is a convenient, cost effective and noninvasive method of determining bone strength well suited to community-based research in countries with limited resources. Although only moderately correlated with dual X-ray absorptiometry (DEXA) …
-
Quantitative Ultrasound Characterization and Monitoring of Locally Advanced Breast Cancer
… changes in quantitative ultrasound (QUS) parameters, including change in average acoustic concentration (AAC) and heterogeneity index, revealed a strong correlation to histologically determined cell death extent (r2=0.64). In the second study, radiofrequency (RF) ultrasound data were …
-
Quantitative ultrasound assessment of thermal therapy in liver
Quantitative ultrasound (QUS) is a promising technique for non-invasive tissue characterization. In this work, the potential of QUS to assess thermal therapy in liver tissue was examined. Specifically, the QUS parameters of attenuation slope, effective scatterer size (ESD), effective acoustic …
-
Retouching History
… day of a three-month archaeological survey near Quseir, Egypt, a small town on the Red Sea cost. This excerpt reports aspects from two different days. Chaper one is an historical flashback detailing a band of determined Jews on a remote Red Sea island in 550 B.C. who are plotting to take back …
-
Improving ultrasonic imaging using novel coded excitation techniques
… REC was combined with quantitative ultrasound (QUS) techniques to improve parametric images of estimated scatterer diameter. Larger bandwidths were observed to lead to a smaller variance in spectral estimates, thereby improving QUS image contrast. Finally, novel techniques for improving the …
-
Three-dimensional acoustic impedance map analysis of soft tissue
… were compared with quantitative ultrasound (QUS) techniques. A chemically fixed section of rabbit liver was scanned ultrasonically, then used to create 3DZMs. ESD estimates were made using the fluid-filled sphere form factor. Twenty-four 3DZMs of volume 300x300x300 cubic microns were …
-
Bone health and physical activity through the various life stages
… and demographic factors, on BMD and bone QUS parameters in the South African population. What sets this thesis apart is that we consider groups that are largely unstudied, groups undergoing demographic and epidemiological transitions, and even groups for whom physical activity may no …
-
Bone properties and skeletal maturity in adolescent males, as assessed by quantitative ultrasound
… in children. Recently, quantitative ultrasound (QUS) technologies have been developed to examine bone properties and skeletal maturity in a safe, noninvasive and cost-effective manner. Objective: The purpose of this study was to compare bone properties and skeletal maturity in competitive male …
-
Risk assessment for osteoporotic fractures among men and women from a prospective population study: the EPIC-Norfolk study
… (DXA) and quantitative ultrasound (QUS). We found that that the predictive power of QUS is comparable to, and independent of, predictive power of DXA. In summary, my studies have added to our knowledge about some novel and easy-to-use risk factors of osteoporosis and proposed a …
-
Bone speed of sound in overweight and normal-weight girls and adolescents
… accelerometry. Using quantitative ultrasound (QUS; Sunlight Omnisense™), bone SOS was measured at the distal radius and mid-tibia. No differences were found between groups in daily total energy, calcium or vitamin D intake. However, all groups were below the recommended daily calcium intake of …
-
A FPGA/DSP based ultrasound system for tumor detection
… The system utilizes Quantitative Ultrasound (QUS) which means sending an ultrasound signal from a transmitter and receiving it at multiple receivers. This received signal is analyzed for echogenic as well as echolucent tumors to differentiate between the two along with non-tumorous sample and …
-
Using two-dimensional impedance maps to study acoustic properties of tissue microstructure
Quantitative ultrasound (QUS) imaging represents a set of techniques for estimating acoustic properties of tissue microstructure that have confirmed potential for identifying disease and monitoring therapy. In one approach to QUS, the backscatter coefficient (BSC) from a tissue is utilized to …
-
Transparent Tissues and Porous Thin Films: A Brillouin Light Scattering Study
… (BLS) and quantitative ultrasound spectroscopy(QUS) that were complimented with low frequency (<5 Hz) dynamic mechanical analysis (DMA). Intact bovine eye globes were also studied with BLS at low power levels, allowing the stiffness of the transparent cornea and lens tissues to be mapped ex-vivo …
-
Characterization of the vaccinia virus ankyrin repeat protein K1 on NF-κB inhibition and its contributions to viral pathogenesis
… non-invasive quantitative ultrasound technology (QUS). Second, infiltrating immune cell populations were decreased in vΔK1L-infected ears. Third, cytokine and chemokine gene expression was decreased in vΔK1L-infected ears. While these results identified the biological basis for smaller lesions …
-
Exercise in Youth and Long-Term Effects on Bone and Joints
… tomography (pQCT) and quantitative ultrasound (QUS) at follow-up. The second study used DXA. Fracture incidence was evaluated in two retrospective cohort studies, one including 397 former male soccer players and 1368 age-matched controls and the second 709 former male athletes in a variety of …
-
Deep structure ultrasound imaging using fundamental and third harmonic coded excitation techniques
A novel coded excitation method, combining Golay coding with fundamental and third harmonic 1, 3 chirps with resolution enhancement compression (REC) and frequency compounding, increases the axial resolution, lateral resolution, penetration depth and the contrast-to-noise ratio (CNR) for an …